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Managing Soils in Agriculture The Impact of Soil Tillage Practices on Soil Fauna A report for the Rural Industries Research and Development Corporation by BC Longstaff, PJM Greenslade, M Colloff, I Reid, P Hart, and I Packer CSIRO Entomology March 1999 RIRDC Publication No 99/18 RIRDC Project No CSE-69a

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© 1999 Rural Industries Research and Development Corporation. All rights reserved. ISBN 0 642 67901 6 ISSN 1440-6845 Managing Soils in Agriculture - The impact of soil tillage practices on soil fauna Publication No. 99/18 Project no CSE-69A The views expressed and the conclusions reached in this publication are those of the author and not necessarily those of persons consulted. RIRDC shall not be responsible in any way whatsoever to any person who relies in whole or in part on the contents of this report. This publication is copyright. However, RIRDC encourages wide dissemination of its research, providing the Corporation is clearly acknowledged. For any other enquiries concerning reproduction, contact the Publications Manager on phone 02 6272 3186.

Researcher Contact Details Dr B C Longstaff CSIRO Entomology Clunies Ross Drive, ACTON ACT 2601 Phone: 02 6246 4181 Fax: 02 6246 4362 Email: [email protected]

RIRDC Contact Details Rural Industries Research and Development Corporation Level 1, AMA House 42 Macquarie Street BARTON ACT 2600 PO Box 4776 KINGSTON ACT 2604 Phone: 02 6272 4539 Fax: 02 6272 5877 Email: [email protected] Website: http://www.rirdc.gov.au Published in March 1999 Printed on environmentally friendly paper by Canprint

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Foreword Soils in Australia are ancient and tend to be shallow, heavily leached and poor in nutrients. Furthermore, climate is unpredictable over much of the arable land, and prone to degradation, especially by intensive, broad acre, arable agriculture. Ploughing and stubble burning are widely used on soils in the south-east of Australia but the effects of these practices remain incompletely understood. These practices result in declining soil organic matter, soil structural degradation, increased runoff and higher erosion. One method of countering these trends is through reducing tillage. Reduced tillage has been found to improve soil structure by increasing surface organic matter and structural stability. This report aims to increase understanding of soil processes and develop practical indicators of these processes by investigating the effects of contrasting tillage and stubble management practices on soil fauna at two sites in the wheat belt of south-east Australia. The results of statistical analyses of selected attributes of the data are presented. Possible implications of the results for management of soils in agriculture are discussed, and the potential for future research is considered. This report, the latest addition to our diverse range of over 250 research publications, forms part of our Resilient Agricultural Systems which aims to enable agricultural production systems that have sufficient diversity, flexibility and robustness to be resilient and respond to challenges and opportunities. This report and others, may be viewed or purchased online at www.rirdc.gov.au Peter Core Managing Director Rural Industries Research and Development Corporation

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Acknowledgments We thank Leslie McKenzie, Suellen Grosse (CSIRO Entomology) and Derek Smith (Australian Museum) for assistance with sorting the samples collected, and Dr John Kirkegaard and Mr Geoff Howe (CSIRO Plant Industry) for information on and maintenance of the Harden site. Elizabeth Straszincki also assisted with data processing.

Abbreviations (see Glossary and Table 1 for definitions) CC — Conventional Cultivation DD — Direct Drilling SI — Stubble Incorporation

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Contents Foreword III Acknowledgments IV Table Of Contents V Abbreviations IV Executive Summary VI

INTRODUCTION 1

OBJECTIVES 2 Study sites 3 Methods 3 Data analysis 6

RESULTS 7 General comments 7 Springtails 7 Mites 31 Other insects 47 Diversity and abundance 51 Soil ecology and management 51 Use as indicators 53

CONCLUSIONS 56

IMPLICATIONS 57

RECOMMENDATIONS 58

APPENDICES 59 Appendix 1 Details of activities on study sites at Cowra during the study period 59 Appendix 2. Springtail species found at the Cowra and Harden sites. 60 Appendix 3. Species and morphospecies of mites fromCowra (FG = functional group). 61

REFERENCES 62

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Executive Summary The first comprehensive survey of soil fauna from soils under wheat and different tillage practices is reported. Soil samples were taken from replicated plots under different tillage treatments at Cowra and Harden in the south-east wheat belt of NSW during spring and autumn in each of three years. A total of 33 species of springtail, 67 species of mites and numerous other arthropod taxa were identified. Mites and springtails were identified to species and allocated to trophic groups, where possible, and abundances of all taxa estimated. Taxa found included some species previously unknown in Australia and some new to science. The diversity of species found in these agricultural fields was comparable to highly productive agricultural systems elsewhere in the world. Abundance was generally high in spring and low in autumn and strongly affected by soil moisture. The data clearly show that springtails respond to the treatments imposed at these sites, although background variation, due to climatic conditions, was very large. Generally speaking, DD and SI plots had increased numbers in both pitfalls and soil cores. Even when springtail numbers are normally high, ie cooler, moister periods, this difference was still evident. The mite data show similar responses to the treatments. Whereas all springtail species showed low abundances under dry conditions, many mite groups were very abundant in Autumn ’96, a dry period. In all cases, the SI and particularly the DD treatments provided the highest abundances. In both of the major faunal groups studied, mites and springtails, the composition of the fauna changed with treatment, with the Direct Drill and Stubble Incorporation exhibiting proportionally higher levels of fungal feeding species. This trophic shift could have significant implications for energy and nutrient pathways in the soil, and the mobilisation of nutrients for plant growth. A number of species in both groups showed potential as indicators of change in soil conditions. One species of springtail (Folsomina onychiurina) and one oribatid mite (Tectocepheus velatus) showed particular promise and would merit further investigation. The ratio of oribatid mites to prostigmatid mites was also discussed as a useful indicator of soil health. The ecological processes underlying the observations on distribution of key soil arthropod groups and their interrelationships with the microbiota and other components of the soil system are discussed. Finally, an assessment of the implications of this research and recommendations for further investigations are presented.

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Introduction Soils in Australia are ancient and tend to be shallow, heavily leached and poor in nutrients. Furthermore, climate is unpredictable over much of the arable land, so much so that it is probable that, for one year in five, farmers will experience drought, making soils more susceptible to erosion by both wind and water. They are therefore prone to degradation, especially by intensive, broad acre, arable agriculture (CSIRO Division of Soils 1983). Ploughing and stubble burning are widely used on soils in the south-east of Australia but the effects of these practices remain incompletely understood. These practices result in declining soil organic matter (Haines & Uren 1990, Gupta et al. 1994, McIntyre 1955, Smith 1969, Steed et al. 1993), soil structural degradation (McIntyre 1955, Smith 1969, Steed et al. 1993, Tisdall & Adem 1986), increased runoff (Packer et al. 1992) and higher erosion (Greenland 1971, Stoneman 1962, Tisdall & Oades 1982). One method of countering these trends is through reducing tillage (Cornish & Pratley 1987). Reduced tillage has been found to improve soil structure by increasing surface organic matter and structural stability (Hamblin 1980, 1984, Packer et al. 1984, Stinner and House, 1990). Biological activity in the soil has been suggested as important in achieving these results (Greenland 1971, Kooistra et al. 1991, Lal 1991, Packer et al. 1992). Although reduced crop production, due to increased levels of fungal pathogens, may initially result from this change, it has been shown that, once land has been direct drilled for about eight years, mean production levels are similar to conventional systems (Neate, 1994). Moreover, DD soils are more resilient, in that they are capable of producing a crop, even in some drought conditions, unlike CC soils. A diverse range of studies around the world have shown that the soil biota is essential to soil health and thus productivity and sustainability of vegetation growing in the soil (Coleman & Crossley 1996, Hendrix et al.1990). This has led to an increasing interest in relationships between components of the soil biota, soil physical properties, soil chemistry and plant production (Anderson 1988, Klopatek et al. 1992, Verhoef & Brussard 1990). The ultimate aim of this research is to design agricultural systems in which soil biota are an integral part so that, rather than ignoring or at worst working against it, the soil biota “works for us” (Elliott & Coleman 1988). These, and other functions are likely to be affected by many agricultural practices, including cultivation, loss of organic material, use of agrochemicals, and “break” crops, such as canola, which produce biocidal compounds (Anderson 1988, Brussard 1994, Coleman & Crossley 1996, Hendrix et al. 1990). However, only basic information on effects of agricultural practices on soil fauna is available for most areas of the world (eg Crossley et al. 1989, Zwart et al. 1994). In data currently available, different effects of some practices have been observed in different locations (Coleman & Crossley 1996, Parmelee et al. 1989). Collecting data in Australia is thus very important. This report describes an investigation of the effects of contrasting tillage and stubble management practices on soil fauna at two sites in the wheat belt of south-east Australia over 3 years. A description of the major faunal groups present and their abundances during spring and autumn is presented, along with aggregated parameters such as diversity and trophic

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structure. The results of statistical analyses of selected attributes of the data are presented. Possible implications of the results for management of soils in agriculture are discussed, and the potential for future research is considered.

Objectives • To produce an account of the differences in the soil fauna and community structure at

two long-term wheat-producing sites, at a Department of Land and Water Conservation (formerly Conservation and Land Management) trial in Cowra and a CSIRO Plant Industry trial, outside Harden. Both trials are looking at the effects of different tillage and stubble-management practices;

• To assess the role of soil fauna in processes leading to changes in soil under reduced tillage.

• To develop further the potential of springtails and mites as bioindicators of soil condition.

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Materials & Methods

Study sites

Two sites in the south-eastern wheat belt at Cowra and Harden were used. Complete descriptions of these sites and the tillage treatments imposed experimentally are published elsewhere (Kirkegaard et al. 1994, 1995, Moran et al. 1988, Packer et al. 1992), so abbreviated information only is provided herein.

Cowra The Cowra site was at the NSW Department of Land and Water Conservation Research Centre (33° 51’S 148°42’E, elevation 384m). The soil is a red duplex type (Dr3.22/Dr3.23) with a hard setting sandy loam surface texture (Northcote 1979). The site is divided into 3 blocks, each 45m wide and 160 to 230m long, separated by uncultivated strips of about 15m width. The long axis of the site runs perpendicular to a slope facing almost due east, as does cultivation. Within each block, 3 tillage treatments were applied: Conventional Cultivation, Direct Drilling and Stubble Incorporation. The treatments were applied to randomly located strips of 15m width. All treatments within each block were sampled. A detailed plan of the site presented in Figure 1. Mean daily maximum temperatures ranged from 30.8°C in January to 12.8°C in July, while minima range from 16.3°C to 3.6°C in the same months. Mean annual precipitation is 645mm, distributed evenly throughout the year. Soil moisture generally restricts plant growth from November to March, when evapotranspiration is more than double precipitation. Monthly precipitation at Cowra over the study period, based on local data, is presented in Figure 2. Details of management activities are given in Appendix 1.

Harden The Harden site was at the CSIRO Tillage & Stubble Management Trial (34°30’S 148°17’E, elevation 497m). The soil is a red earth (Gn 2.14) with a sandy clay loam surface texture (Northcote 1979). The site is divided into 4 contiguous blocks of 42m width and 40m length, running perpendicular to a gentle 3% slope facing southeast. Within each block, 7 tillage treatments were applied to randomly located strips of 6m width, each strip and the line of cultivation running down the slope. Of these treatments, only those termed “Burn-Minimum till” and “Bash-Direct drill” by Kirkegaard et al. (1994, 1995) were sampled within each block. To simplify terminology, the same names are used in this report as for the equivalent treatment at Cowra. Thus “Burn-Minimum till” is referred to as “Conventional Cultivation”, and “Bash-Direct drill” is referred to as “Direct Drill”. A detailed plan of the Harden site presented in Figure 1. Mean daily temperatures, mean annual precipitation and rainfall distribution are similar to those at Cowra, as is soil moisture. Monthly precipitation at Harden over the period of the study, based on local data, is presented in Figure 2.

Methods Sampling for invertebrates was carried out over three years on the dates shown in Tables 1 and 2. The type and stage of crop is also given in the table and three different crops were planted in each of the years, as would be normal farming practice for the region. Two methods were used for sampling, funnel extraction of soil cores which collected mainly the microarthropods, and pitfall traps, which collected surface active mesofauna and macroinvertebrates. Two stainless steel cores of diameter 5 cm and 5 cm deep were inserted into the group, one vertically above the other so that two cores of soil, one of 0-5 cm and one of 5-10cm, could be removed. The soil was returned to the laboratory and placed in simple

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plastic funnels within 24 hours. The funnels were 22cm in diameter and 22cm deep having a perforated aluminium sieve inserted into the top about 3cm from the rim. Perforations were 0.5mm in diameter and the sample was pushed out of the stainless steel core. spread out and crumbled on the sieve. The soil was left for five days to extract and room temperature were gradually raised during the period from ambient to about 30oC. The timing of sampling was chosen to coincide with two different stages of the crop and field and two different seasons. One was in late summer after cultivation but before planting and the other in spring, when the crop was well grown but before harvesting. Cowra was sampled six times over three years and Harden sampled five times. In 1994 when sampling commenced, drought conditions prevailed but the drought had broken before the spring sampling in 1995. a. Cowra

b. Harden

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5 0 m5 0 m Figure 1. Maps of the experimental layout at the two study sites.

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Figure 2. Monthly rainfall at Cowra and Harden over the study period. The numbers

above each graph indicate the timing of sampling Pitfall sampling was carried out using Macartney bottles, of dimensions 1.8 cm diameter by 8.0 cm, three-quarters filled with a absolute alcohol and left in the ground for about 5 days. The method is described in detail in Greenslade and Greenslade (1971) and the number of samples and dates of collection given in Tables 1 and 2. Studies of the nematode fauna and microbial fauna and flora were conducted on these sites at the same time and will be published elsewhere. Only the springtails, mite and other invertebrate data will be reported here.

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Table 1 Sampling at Cowra Year 1994 1995 1995 1996 1996 1997 Date 17 October 27 April 4 Sept 23 April 25 September 13 May Crop Lupins Unplanted Wheat Unplanted Canola Unplanted Variety Gungaroo Dollarbird Oscar Stage of crop Seeding Date 17 -22 October 27 April-2 May 4 - 9 September 23-28 April 25-30 September 13 May No. of pitfalls 90 90 90 90 90 - Date 17 October 27 April 4 September 23 April 25 September 13 May No. of soil cores 90 at 0-5 cm90 at

5-10 cm 90 at 0-5 cm90 at 5-10 cm

90 at 0-5 cm90 at 5-10 cm

90 at 0-5 cm 90 at 5-10 cm

90 at 0-5 cm 90 at 5-10 cm

90 at 0-5 cm 90 at 5-10 cm

Table 2 Sampling at Harden

Year 1994 1995 1995 1996 1996 Date 17 October 27 April 4 September 24 April 25 September Crop Canola Lupins Wheat? Variety ? Stage of crop ? fallow fallow Date 17 -22 October 27 April-2 May 4 - 9 Sept 23-28 April 25-30 September No. of pitfalls 40 40 40 40 40 Date 17 October 27 April 4 Sept 24 April 25 September No. of soil cores

40 at 0-5 cm40 at 5-10 cm

40 at 0-5 cm40 at 5-10 cm

40 at 0-5 cm40 at 5-10 cm

40 at 0-5 cm40 at 5-10 cm

40 at 0-5 cm40 at 5-10 cm

Data analysis Data for which there were non-zero values for all sites, such as total abundance or number of species, were analysed statistically using ANOVA. Differences between site layouts at Harden and Cowra meant that different ANOVA designs were required. Harden data sets were analysed using a two-way ANOVA (2 treatments x 4 blocks) with replication, whilst Cowra data sets required a simple one-way design. All sets data analysed were checked for heteroscedasticity and conformity to the assumed distribution using plots of residuals versus fitted values, half-normal plots and frequency histograms. Data sets were transformed using an appropriate function if doing so made it conform more closely to the assumed distribution, as indicated in the results. Species diversity within communities can be summarised in an index. Many such indices exist, each having their own benefits and drawbacks. The diversity of these communities was assessed using the Simpson Index (Simpson, 1949), which is both simple to calculate and relatively unbiased (Lande, 1996). This is calculated as:

∑=

−=S

iipI

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where pi is the frequency of species I in the community and S is the total number of species in the community. The nearer the value of the index to 1, the higher the diversity.

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Results

General comments The samples from both soil cores and pitfall traps were sorted into springtails (Collembola), mites (Acari) and other insects. Of these, only the springtails and mites were identified further. The mite fauna proved to be very much more abundant and diverse than anticipated and, furthermore, included a very large proportion of previously undescribed species. This became a severe impediment to progress and, as a consequence, the mite fauna could not be completely analysed. For the purposes of this report, only the mite fauna collected from soil cores at Cowra will be described. The Harden material will be described in detail at a later date. Pitfall sampling also had some drawbacks, the most severe being the large variation in ability to trap different taxa. The catch size is an indication of population index of activity as well as a measure of population density. Another problem was the apparent attractiveness of the pitfall traps to large birds, such as Magpies and Currawongs, which frequently pulled the traps out of the ground, especially at Cowra. This meant that, on many occasions, numerous traps were lost, further reducing the value of this method. All pitfall catches were sorted to order but only the springtails were identified to species level. Because of the limitations mentioned previously, most of the pitfall data were not analysed statistically. What follows is therefore primarily a description and analysis of the data collected from the soil cores. The relative abundance of arthropod orders is shown in Table 3. The combined data from cores and pitfalls suggested that the Cowra site is slightly more diverse than the Harden site. This is primarily because springtails collected from pitfalls at Harden were almost 20 times as abundant than the next most common order, i.e. mites. The Cowra pitfall samples showed the same ranking but the ratio was only about 2 to 1. At both sites, the ranking was reversed in the soil core samples. All other taxonomic groups were at least an order of magnitude less frequent (Table 3). The pitfall data were probably somewhat aberrant, in that the springtails produced far higher numbers than expected and mites far lower. The former was probably due, in part, to the presence of sheep dung, as discussed below, which appeared to influence the populations of two springtail species. The low mite numbers collected from these pitfall samples could not be explained. The other notable issue from these data was the very high initial abundance of ants (Formicidae) collected from the Cowra pitfall traps. These data will be discussed later.

Springtails

Abundance and species diversity A total of 33 species of springtail were found over both sites during the study period (Appendix 2). Overall species abundance curves for the two sites revealed that the Cowra site was marginally more diverse than Harden (Table 4), which is reflected in the Simpson Index (0.74 vs 0.64). Breaking the data up into treatments, a more complex picture emerged for the Cowra site. Changing to conventional cultivation had a negative impact on diversity, particularly in the original SI treatment, whilst changing to stubble-incorporation had a significantly beneficial effect on the diversity of springtails in the CC treatment (Table 5). This was probably a result of increasing soil organic carbon content. The differences between treatments were much more obvious at Harden, where the CC treatment was noticeably less diverse than the DD treatment (0.49 vs 0.72). At all times,

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the density of springtails extracted from Cowra soil cores was lower than from Harden and, with the exception of 1997, autumn densities were always lower than those found in the Spring (Table 6). Dry conditions were evident in Spring ’94, Autumn ’95 and Autumn ’96 and more than 50% of the fauna was found in the lower sample. Differences in overall density of springtails at the two sites were greater during the drier periods (Table 6). Analyses of variance of the total springtails collected at the two sites failed to find any significant differences, largely because of climatic variability between sampling periods (Figure 3). However, except for Autumn ‘96, the total number of springtails recovered from DD soil cores at Harden was significantly greater than from CC cores (Figure 4).

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Figure 3. The abundance of springtails collected from cores in each treatment at Cowra. The white columns are the CC treatment, the striped columns the DD treatment and the black columns the SI treatment.

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Figure 4. Effect of treatment on the abundance of springtails collected from Harden soil cores. White columns are the CC treatment, striped columns the DD treatment.

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Table 3. Abundance of arthropod orders at the study sites over the study period COWRA HARDEN

Soil cores N Pitfalls N Soil cores N Pitfalls N Acari 37495 Collembola 38575 Acari 16778 Collembola 48691 Collembola 12045 Acari 16866 Collembola 13614 Acari 2568 Formicidae 550 Formicidae 11449 Larvae 481 Formicidae 1782 Larvae 482 Hemiptera 6297 Araneae 120 Diptera 635 Hemiptera 430 Thysanoptera 2066 Formicidae 69 Hemiptera 198 Pauropoda 213 Diptera 1227 Coleoptera 42 Coleoptera 96 Symphyla 208 Coleoptera 526 Hemiptera 34 Araneae 64 Thysanoptera 153 Hymenoptera 277 Symphyla 30 Larvae 55 Araneae 133 Larvae 259 Thysanoptera 26 Hymenoptera 38 Coleoptera 113 Araneae 133 Psocoptera 15 Thysanoptera 36 Psocoptera 64 Psocoptera 64 Hymenoptera 15 Dermaptera 19 Diptera 46 Lepidoptera 27 Chilopoda 12 Psocoptera 19 Isoptera 17 Chilopoda 27 Diptera 10 Chilopoda 4 Chilopoda 16 Neuroptera 15 Nematoda 9 Lepidoptera 2 Hymenoptera 11 Orthoptera 15 Pauropoda 5 Neuroptera 2 Diplopoda 1 Dermaptera 11 Neuroptera 1 Orthoptera 1 Diplopoda 4 Blattodea 2 Pauropoda 1

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Table 4. Relative abundance of springtails at the study sites over the study period. COWRA HARDEN

Soil cores N Pitfalls N Soil cores N Pitfalls N Brachystomella platensis

5037 Jeannenotia stachi 12757 Hypogastrura vernalis

6292 Hypogastrura vernalis

21255

Cryptopygus thermophilus

2891 Hypogastrura manubrialis

8122 Cryptopygus thermophilus

1667 Ceratophysella gibbosa

3642

Mesaphorura macrochaeta

803 Brachystomella platensis



3301

Folsomina onychiurina

603 Entomobrya unostrigata

1765 Ceratophysella gibbosa

957 Katianna australis

1404

Folsomides parvulus

450 Katianna australis 1670 Mesaphorura macrochaeta

301 Cryptopygus thermophilus

1402

Hypogastrura vernalis

392 Sphaeridia sp. 1612 Jeannenotia stachi 111 Entomobrya unostrigata

1091

Ceratophysella gibbosa

381 Sminthurinus elegans

1032 Entomobrya unostrigata

68 Jeannenotia stachi

1064

Jeannenotia stachi 311 Drepanura cinquilineata

959 Katianna australis 58 Entomobrya unostrigata

911

Sminthuridae imm 249 Ceratophysella gibbosa

812 Folsomina onychiurina

57 Sminthurinus mime

521

Sphaeridia sp. 242 Cryptopygus thermophilus

292 Sminthurinus sp. 3 47 Ascocyrtus sp. 509

Katianna australis 97 Lepidosira nigrocephala

187 Folsomides parvulus 43 Fasciosminthurus virgulatus

459

Sminthurinus sp. 3 71 Sminthurinus sp. 3 80 Ascocyrtus sp. 23 Sminthurinus elegans

48

Sminthurinus elegans

40 Drepanura coeruleopicta

73 Pseudosinella sp. 7 Sminthurinus sp. 3

20

Ascocyrtus sp. 31 Ascocyrtus sp. 69 Entomobrya multifasciata

6 Sminthurinus sp.4

17

Hypogastrura manubrialis

31 Entomobrya multifasciata

29 Isotomodes productus

6 Pseudosinella sp.

7

Isotomodes productus

26 Sinella sp. 20 Sinella sp. 5 Proisotoma filifera

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Megalothorax sp. 24 Proisotoma minuta 11 Sminthurinus mime 4 Entomobrya multifasciata

5

Entomobrya unostrigata

23 Mesaphorura macrochaeta

5 Fasciosminthurus virgulatus

2 Sphaeridia sp. 1

Drepanura coeruleopicta

22 Corynephoria reticulata

2 Sminthurinus sp.4 1 Folsomides parvulus

1

Drepanura cinquilineata

17 Folsomides parvulus

2 Entomobrya virgata 1 Sinella sp. 1

Sinella sp. 16 Megalothorax sp. 1 Folsomina onychiurina

1

Lepidosira nigrocephala

3 Sminthurinus elegans 1

Xenylla sp. 2 Sminthurinus sp. black

1

Entomobrya virgata

2

Xenylla greensladeae

2

Entomobrya multifasciata

2

Isotoma sp. 1

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Table 5. The effect of treatment on the Simpson Index for springtails at Cowra. Current Treatment

Original treatment CC DD SI DD (1) 0.72 0.75 0.70 SI (2) 0.63 0.74 0.82 CC (3) 0.59 0.59 0.81

Table 6 The abundance of springtails collected from soil cores over the study period. Spring 94 Autumn 95 Spring 95 Autumn 96 Spring 96 Autumn 97 Cowra Total nos 187 17 5030 484 2479 3820 Density/m2 1,058 96 28,464 2,739 14,028 21,619 % in top 2 18 85 45 87 83 No. of species 7 7 19 16 18 22 Harden Total nos 1063 893 3123 3226 5279 - Density/m2 13,500 11,363 39,740 41,050 67,244 - % in top 0 88 86 95 91 Nos of species 5 12 18 14 15 -

Trophic structure Species were classified into ecological groups on two different characteristics based on existings information on each species. The characteristics reflected their role in the ecosystem and their contribution to soil processes. The first characteristic was position in the soil profile, based on morphology (Petersen, 1982), which divided species into three groups. This also conforms to the heuristic model of Greenslade and Greenslade (1983) and used in the analysis of Australian grassland springtails by Greenslade and Greenslade (1989). The three groups were: • Epigaeic, above ground, species, • Surface active, hemiedaphic species, • Soil living, euedaphic species. The second characteristic was feeding type on mouthpart morphology and gut contents. The following groups were used: • Predators on nematodes, also bacterial feeders. • Fungal feeders, as evidenced by fungal hyphae and spores in gut, also grazers on dead

organic material including roots. • External digestors • Live plants including pollen • Omnivores/ scavengers. The matrix shown in Table 7 shows the key characteristics of the functional groups into which all species encountered could be inserted. The groups are not inflexible but are part of a continuum and some generalisations had to be made. Immature specimens were placed in a different group to adults if their microhabitat preferences warranted it. It would have been meaningless to make statistical comparisons between the two sites and so they will be discussed separately. Table 7. Functional groups of springtails. Those occurring at the Cowra and Harden sites are in the white cells. Letters indicate the name of the functional group, as used in the text from here on.

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Feeding type Vertical

distribution Predators on nematodes

and bacteria

Fungal feeders

External digesters

Herbivores Omnivores/ Scavengers

Epigaeic (Above ground) A F Hemiedaphic

(Surface) B C G E Euedaphic (Within soil) D

Cowra Over 70% of the springtails collected from Cowra soil cores during this study was accounted for by just two functional groups (Table 8). However, repeating this process for each sampling period yielded a somewhat different picture and it was clear that some functional groups were more adversely affected by dry conditions than others (Table 9). Functional groups B and E were noticeably under-represented or absent during Spring ’94, Autumn ’95 and Autumn ’96, when compared to the other sampling periods and to the overall picture. The data from the pitfall traps presented a very different picture, with group A being by far the most common group and group D the least common. Groups D and E were essential absent from the pitfall samples collected in the dry periods of Spring ’94, Spring ’95 and Autumn ’96 (Table 8). Table 8. Functional group composition (% of total abundance) of the springtail fauna collected from soil cores at Cowra. Soil cores Functional

group Overall Spring

‘94 Autumn

‘95 Spring

‘95 Autumn

‘96 Spring

‘96 Autumn

‘97 A 4 1 12 5 5 4 3B 42 0 0 46 1 39 46C 30 68 41 30 41 30 27D 16 29 47 6 53 23 19E 8 2 0 13 0 4 5

Pitfall traps Functional


‘94 Autumn

‘95 Spring

‘95 Autumn

‘96 Spring

‘96 A 48 36 76 51 54 32B 14 19 0 16 0 13C 14 45 23 9 46 15D 0 0 1 0 0 0E 24 0 0 24 0 40

Functional group A

14

Cores

0

25

50

75

100

125

Jeannenotia stachi Katianna australis Entomobryaunostrigata

Drepanuracoeruleopicta

Drepanuracinquilineata

Lepidosiranigrocephala

Entomobrya virgata

Abu

ndan

ce

Pitfalls

0

2500

5000

7500

10000

12500

Jeannenotia stachi Entomobryaunostrigata

Katianna australis Drepanuracinquilineata

Lepidosiranigrocephala

Drepanuracoeruleopicta

Entomobryamultifasciata

Corynephoriareticulata

Abu

ndan

ce

Figure 5. Species abundance within functional group A at Cowra.

Cores

0

50

100

150

200

250

Spring '94 Autumn 95 Spring '95 Autumn 96 Spring '96 Autumn 97

Abu

ndan

ce

Pitfalls

0

2500

5000

7500

10000

12500

Spring '94 Autumn '95 Spring '95 Autumn '96 Spring '96

Abu

ndan

ce

Figure 6 Abundance of functional group A in each sampling period at Cowra.

15

S pr ing 94

0

0.2

0.4

0.6

0.8

1

1.2

DDI S II C C I DDII S III C C II D D III S IIII CC III

Ab

unda

nce

Autum n 95

0

0.2

0.4

0.6

0.8

1

1.2

D DI S II CC I DD II S III CC II D D III S IIII C C III

Ab

unda

nce

S pr ing 95

0

10

20

30

40

50

60

D DI S II CC I DDII S III C C II D D III S IIII C C III

Abu

nda

nce

Autum n 96

0

2.5

5

7.5

D DI S II CC I D DII S III C C II DD III S IIII CC III

Abu

ndan

ce

S pr ing 96

0

10

20

30

40

50

60

D DI S II C C I D DII S III C C II D D III S IIII CC III

Abu

ndan

ce

Autum n 97

0

10

20

30

40

DDI S II CC I DD II S III CC II DD III S IIII CC III

Abu

ndan

ce

Figure 7. The abundance of springtails from functional group A from soil cores in each treatment at Cowra. This group comprised 9 species, the most common of which was Jeannenotia stachi, particularly in the pitfall traps (Figure 5). These species were essentially absent from soil cores from the first two sampling periods but were collected in low numbers from the pitfall traps (Figure 6). Analysis of variance on the complete soil core data set failed to show any significant effect of treatment (P=0.06) (Figure 7). Numbers were insufficient to allow analysis of any single species. J. stachi was present in particularly high numbers in Spring ’95, constituting 44% of all springtails collected from pitfalls in this period. There is no obvious explanation for this dramatic response. Virtually all of the Entomobrya unostrigata were collected from pitfall traps in Autumn ’94 and Spring ’95. In the latter period, this species comprised about 96% of the springtails collected in pitfall traps. Analysis of variance on the pitfall data failed to show any significant effect of treatment on this species. Functional group B

Cores

0

500

1000

1500

2000

2500

Spring 94 Autumn95 Spring 95 Autumn96 Spring 96 Autumn97

Abu

ndan

ce

Pitfalls

0

2500

5000

7500

10000

12500


Abu

ndan

ce

Figure 8. Abundance of functional group B in each sampling period at Cowra.

16

Spr ing 95

0

90

180

270

360

DDI S II CCI DDII S III CCII DDIII S IIII CCIII

Ab

unda

nce

Autumn 96

0

0.5

1


Abu

nda

nce

Spr ing 96

0

130

260

390

520


Abu

nda

nce

Autumn 97

0

200

400

600


Abu

ndan

ce

Figure 9. The abundance of springtails from functional group B from soil cores in each treatment at Cowra. This group was represented by a single species, Brachystomella platensis, which was only found in pitfall traps in Spring ’94 and was completely absent in Autumn ’95 and again in Autumn ’96 (Figure 8). Analysis of variance of the complete soil core data set failed to show any significant effects due to treatment in either core (P=0.6) or pitfall data (P>0.99). However, when the soil core data for each sampling period were analysed separately, there were significant differences in Spring ’96 (P=0.0024) and Autumn ’97 (P=0.00002). The analysis of differences, using Tukey’s Method, revealed that, for Spring ’96, the CC2 treatment had a significantly greater population of B. platensis than SI2, SI3 or CC3 (Figure 9). In Autumn ’97, it was the CC3 treatment that had a significantly greater population than any of the SI treatments or DD2 (Figure 9). Functional group C Whilst a total of 8 species were found, the composition of this functional group differed between the two sampling methods. In the soil core samples, composition was dominated by Cryptopygus thermophilus, whilst in the pitfall samples, it was immature E. unostrigata, which belong to a different functional group to the adults (Figure 10). Again, the first two sampling periods produced only very low numbers of springtails from this functional group (Figure 11). As with the previous group, ANOVA of the complete data set failed to show any significant effects due to treatment (P=0.14) but when each sampling period was analysed separately, there were significant differences in Spring ’95 (P<0.0004), Spring ’96 (P<<0.00001) and Autumn ’97 (P=0.0012). For Spring ’95, the DD1 treatment produced significantly more specimens, whilst for Spring ’96, it was DD2 and for Autumn ’97, it was CC3 (Figure 12).

17

Cores

0

500

1000

1500

2000

2500

3000

Cryptopygusthermophilus

Sminthuridae imm Sphaeridia sp. Sminthurinus sp. 3 Isotomidae imm Sminthurinuselegans

Ascocyrtus sp. Entomobryidae imm Xenyllagreensladeae

Abu

ndan

ce

Pitfalls

0

500

1000

1500

2000

2500

Entomobry idaeimm

Sphaeridia sp. Sm inthurinuselegans

Cryptopygusthermophilus

Sminthurinus sp. 3 Ascocyrtus sp. Sm inthuridae imm Isotomidae imm Proisotoma minuta

Abu

ndan

ce

Figure 10. Species abundance within functional group C at Cowra.

Cores

0

500

1000

1500

Spring '94 Autumn '95 Spring '95 Autumn '96 Spring '96 Autumn '97

Abu

ndan

ce

Pitfalls

0

700

1400

2100


Abu

ndan

ce

Figure 11. Abundance of functional group C in each sampling period at Cowra.

18

Spring 94

0

8

16

24

32

DDI SII CCI DDII SIII CCII DDIII SIIII CCIII

Abu

ndan

ceAutumn 95

0

1

2


Abu

ndan

ce

Spring 95

0

130

260

390

520


Abu

ndan

ce

Autumn 96

0

40

80

120


Abu

ndan

ce

Spring 96

0

110

220

330


Abu

ndan

ce

Autumn 97

0

80

160

240


Abu

ndan

ce

Figure 12. The abundance of springtails from functional group C from soil cores in each treatment at Cowra. Functional group D This group contained 8 species (Figure 13). The pattern of abundance differed somewhat from other groups in that numbers collected increased over time (Figure 14) and also produced very marked differences between treatments (P=0.0001). Pitfall samples yielded very low numbers (Figure 14). It is clear from Figure 15 that, except for the first two sampling periods, when drought conditions prevailed, continuous DD treatment (DD1) showed the highest levels of this group. The other two treatments from the block that was originally DD (SI1 and CC1) showed reduced levels, although SI1 is always higher than CC1. Looking at individual sampling periods, significant differences were found in Spring ’95 (P<0.0005), Spring ’96 (P=0.02) and Autumn ’97 (P<0.00001). In most cases, this significance was due to the very low levels found in two of the treatments from the original CC block (DD3 and CC3) (Figure 15). Interestingly, the other treatment from this block (SI3) showed substantial increases when compared to the other two treatments. Species in this functional group appeared to be responding quite quickly to increased levels of soil organic matter below the surface.

19

Cores

0

160

320

480

640

Mesaphoruramacrochaeta

Folsominaonychiurina

Folsomidesparvulus

Mesaphorura spp. Isotomodesproductus

Megalothorax sp. Sinella sp.

Abu

ndan

ce

Pitfalls

0

2000

4000

6000

8000

Hypogastrura manubrialis Ceratophysella gibbosa Hypogastrura imm

Abu

ndan

ce

Figure 13. Species abundance within functional group D at Cowra.

Cores

0

150

300

450

600

750


Abu

ndan

ce

Pitfalls

0

3

6

9


Abu

ndan

ce

Figure 14. Abundance of functional group D in each sampling period at Cowra

20

Spring 94

0

4

8

12


Abu

ndan

ceAutumn 95

0

1

2

3

4

5


Abu

ndan

ce

Spring 95

0

25

50

75


Abu

ndan

ce

Autumn 96

0

15

30

45


Abu

ndan

ce

Spring 96

0

50

100

150

200


Abu

ndan

ce

Autumn 97

0

50

100

150


Abu

ndan

ce

Figure 15. The abundance of springtails from functional group D from soil cores in each treatment at Cowra. Data for the three most common species within this functional group, Mesaphorura macrochaeta, Folsomina onychiurina and Folsomides panulus were analysed separately. The last of these showed no significant effects of treatment (P=0.08), whereas the other two species did (P=0.022 and 0.045, respectively). Relatively low numbers prevented statistical analysis of individual sampling periods but the basic effects can be seen from the curves shown in Figure 16. It is difficult to deduce much about the responses of either species on the treatments that were originally SI. However, F. onychiurina was able to respond positively to the enhanced soil organic levels in the SI treatment within the original DD, whereas M. macrochaeta was not and, in fact seemed to be disadvantaged by the limited tillage that took place. In sharp contrast, this species showed a rapid and large positive change in the SI treatment from the original CC treatment that was sustained over the last four sampling periods.

21

a)

0

0.2

0.4

0.6

0.8

1

1.2

1.4


Ave

rage

num

ber p

er tr

ap

d)

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2


Ave

rage

num

ber p

er tr

ap

b)

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8


Ave

rage

num

ber p

er tr

ap

e)

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7


Ave

rage

num

ber p

er tr

ap

c)

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1


Ave

rage

num

ber p

er tr

ap

f)

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45


Ave

rage

num

ber p

er tr

ap

Figure 16. Effect of treatment upon abundance of two key species of springtail at Cowra. Graphs a-c show Folsomina onychiurina and graphs d-e show Mesaphorura macrochaetae. The first row is for the original DD treatment; the second row for the original SI treatment and the third row for the original CC treatment. The solid line depicts the new DD treatments; the dashed line depicts the new CC treatments; the dotted line depicts the new SI treatments. Functional group E This group consisted of 3 species, Hypogastrura manubrialis, Hypogastrura vernalis, and Ceratophysella gibbosa (Figure 17). The first of these was only found in low numbers (Figure 18). The group was absent in Autumn ’95 and only in very low numbers in Spring ’94 and Autumn ’96. The highest numbers were found in Spring ’95 and one treatment (SI3 produced quite high numbers (Figure 19). This is probably a reflection of the clumped distribution of these species. Analysis of variance failed to show any significant effects due to treatment (P=0.19).

22

C o r es

0

100

200

300

400

H y pogas t ru ra ve rna lis C e ra tophy s e lla g ibbos a H y pogas tru ra im m C era tophy s e lla im m H y pogas t ru ra m anub ria lis

Abu

ndan

ce

Figure 17. Species abundance within functional group E at Cowra.

Cores

0

130

260

390

520

650


Abu

ndan

ce

Pitfalls

0

2000

4000

6000


Abu

ndan

ce

Figure 18. Abundance of functional group E in each sampling period at Cowra

Harden Over 60% of the springtails collected from Harden was accounted for by functional group E (Table 9). Considering each sampling period separately, Spring ‘94, Autumn ‘96 and Spring ‘96 showed basically the same picture, with group E constituting between 77 and 81% of specimens collected, but Autumn ’95 and Spring ’95 were quite different (Table 9). In Autumn ’95, 82% of specimens collected were from group B. Table 9 Functional group composition (% of total abundance) of the springtail fauna collected from soil cores at Harden Functional


‘94 Autumn

‘95 Spring

‘95 Autumn

‘96 Spring

‘96 Autumn

‘97 A 2 0 3 6 2 4 1B 14 0 82 28 3 39 3C 16 20 10 28 17 30 10D 4 3 3 8 1 23 3E 64 77 2 30 77 4 83

23

Spring 94

0

1

2


Abu

ndan

ceSpring 95

0

150

300

450


Abu

ndan

ce

Autumn 96

0

1

2


Abu

ndan

ce

Spring 96

0

5

10

15

20

25


Abu

ndan

ce

Autumn 97

0

25

50

75

100


Abu

ndan

ce

Figure 19. The abundance of springtails from functional group E in each treatment at Cowra. Functional group A This functional group comprised 5 species, the most common of which was again J. stachi (Figure 20). No specimens were found in the first sampling period and only modest numbers at other times (Figure 21). Highest numbers were found in Spring ’95 (Figure 22). Analysis of variance failed to detect any significant effect due to treatment (P=0.43).

Cores

0

40

80

120

Jeannenotia s tachiimm

Entomobryaunostrigata

Katianna australisimm

Katianna australis Entomobryamultifasciata

Jeannenotia s tachi Entomobrya virgata

Abu

ndan

ce

Figure 20. Species abundance within functional group A at Harden.

24

Cores

0

50

100

150

Spring 94 Autumn95 Spring 95 Autumn96 Spring 96

Abu

ndan

ce

Figure 21. Abundance of functional group A in each sampling period at Harden

Autumn 95

0

2

4

6

8

10

ICC

IICC

IIICC

IVCC

IDD

IIDD

IIIDD

IVDD

Abu

ndan

ce

Spring 95

0

10

20

30

40

50

ICC

IICC

IIICC

IVCC

IDD

IIDD

IIIDD

IVDD

Abu

ndan

ce

Autumn 96

0

5

10

15

20

25

ICC

IICC

IIICC

IVCC

IDD

IIDD

IIIDD

IVDD

Abu

ndan

ce

Spring 96

0

2

4

6

8

10

ICC

IICC

IIICC

IVCC

IDD

IIDD

IIIDD

IVDD

Abu

ndan

ce

Figure 22. The abundance of springtails from functional group A from each treatment at Harden.

Functional group B As at Cowra, this group was predominantly comprised of B. platensis, although two specimens of Fasciosminthurinus virgulatus were collected during the study. The species was absent in Spring ’94, appeared in quite high numbers in Autumn ’95 and showed a steady

25

decline thereafter (Figure 23). The Autumn ’95 sample was dominated by two replicates (Figure 24), which skewed the contribution of this group to the overall faunal composition for that sampling period. This reflects the somewhat clumped distribution shown by this species. Analysis of variance did show a significant effect of treatment over the entire study period (P=0.017), with higher numbers being found on the DD treatment. There was also a significant interaction between treatment and time (P=0.004), with the Autumn ’95 sample standing out (P=0.025).

C o res

0

210

420

630

840

S pring 94 A u tum n95 S pring 95 A u tum n96 S pring 96

Abu

ndan

ce

Figure 23. Abundance of functional group B in each sampling period at Harden

Autumn 95 Group B

0

140

280

420

ICC

IICC

IIICC

IVCC

IDD

IIDD

IIIDD

IVDD

Abu

ndan

ce

Spring 95 Group B

0

70

140

210

ICC

IICC

IIICC

IVCC

IDD

IIDD

IIIDD

IVDD

Abu

ndan

ce

Autumn 96 Group B

0

10

20

30

40

50

IC

C III CC I

DD III DD

Abu

ndan

ce

Spring 96 Group B

0

8

16

24

32

IC

C III CC I

DD III DD

Abu

ndan

ce

Figure 24. The abundance of springtails from functional group B from each treatment at Harden. Functional group C This group contained 8 species but was dominated by Cryptopygus thermophilus (Figure 25). As with the others groups, populations were quite small in the first two sampling periods, but much larger in the last three (Figure 26). Analysis of variance narrowly failed to show any overall effect of treatment (P=0.053), but when looked at individually, Spring ’95 (P=0.0017) and Spring ’96 (P=0.00007) showed significantly higher populations on the DD treatment

26

(Figure 27). For Spring ’95, there was also a significant degree of variability between the replicates (P=0.005), with replicate 2, in particular showing substantially higher populations.

Cores

0

300

600

900

1200

1500

1800C

rypt

opyg

usth

erm

ophi

lus

Smin

thur

idae

imm

Smin

thur

inus

sp.

3

Ento

mob

ryid

ae im

m

Asc

ocyr

tus

sp.

Isot

omid

ae im

m

Smin

thur

inus

mim

e

Smin

thur

inus

ele

gans

Smin

thur

inus

sp.

bla

ckim

m

Smin

thur

inus

sp.

4

Abu

ndan

ce

Figure 25. Species abundance within functional group C at Harden.

C ores

0

100

200

300

400

500

600

700

S pring 94 A utum n95 S pring 95 A utum n96 S pring 96

Abu

ndan

ce

Figure 26. Abundance of functional group C in each sampling period at Harden.

27

Spring 94

0

25

50

75

ICC

IICC

IIICC

IVCC

IDD

IIDD

IIIDD

IVDD

Abu

nda

nce

Autumn 95

0

20

40

60

80

ICC

IICC

IIICC

IVCC

IDD

IIDD

IIIDD

IVDD

Abu

nda

nce

Spring 95

0

90

180

270

ICC

IICC

IIICC

IVCC

IDD

IIDD

IIIDD

IVDD

Ab

und

ance

Autumn 96

0

80

160

240

ICC

IICC

IIICC

IVCC

IDD

IIDD

IIIDD

IVDD

Ab

und

ance

Spring 96

0

25

50

75

100

ICC

IICC

IIICC

IVCC

IDD

IIDD

IIIDD

IVDD

Abu

nda

nce

Figure 27. The abundance of springtails from functional group C from each treatment at Harden. Functional group D This group contained 7 species but was dominated by M. macrochaeta (Figure 28). This group was found in modest levels in the first two sampling periods, but increased subsequently (Figure 29). Analysis of variance suggested that there was a significant effect of treatment (P=0.017), with higher overall levels on the DD treatment (Figure 30). Data for the most common species within this functional group, M. macrochaeta, were analysed separately. The significance level rose slightly (P=0.015). Relatively low numbers prevented analysis of individual sampling periods.

C o r es

0

100

200

300

M es apho ru ram ac roc hae ta

F o ls om inaony c h iu rina

F o ls om idespa rvu lus

P s eudos ine llas p .

Is o tom odesp roduc tus

S ine lla s p . M ega lo tho raxs p .

Abu

ndan

ce

Figure 28. Species abundance within functional group D at Harden.

28

Cores

0

50

100

150

200

Spring 94 Autumn95 Spring 95 Autumn96 Spring 96

Abu

ndan

ce

Figure 29. Abundance of functional group D in each sampling period at Harden

Spring 94

0

10

20

30

ICC

IICC

IIICC

IVCC

IDD

IIDD

IIIDD

IVDD

Abu

ndan

ce

Autumn 95

0

5

10

15

ICC

IICC

IIICC

IVCC

IDD

IIDD

IIIDD

IVDD

Abu

ndan

ce

Spring 95

0

15

30

45

ICC

IICC

IIICC

IVCC

IDD

IIDD

IIIDD

IVDD

Abu

ndan

ce

Autumn 96

0

5

10

15

ICC

IICC

IIICC

IVCC

IDD

IIDD

IIIDD

IVDD

Abu

ndan

ce

Spring 96

0

20

40

60

ICC

IICC

IIICC

IVCC

IDD

IIDD

IIIDD

IVDD

Abu

ndan

ce

Figure 30. The abundance of springtails from functional group D from each treatment at Harden. Functional group E

29

This group consisted of 3 species, H . manubrialis, H. vernalis, and C. gibbosa. They were in low numbers in the first three sampling periods, but increased substantially subsequently. (Figure 31). Virtually none were found in Autumn ’95. In Autumn ’96, 69% of the collection consisted of H. vernalis from one replicate (CC4) and 98% from just two replicates (the other being CC3) (Figure 32). Analysis of variance failed to show any significant effects due to treatment (P=0.73). Looking at individual species, C. gibbosa showed no significant response to treatment overall but did show a significantly higher populations on DD treatments in Spring ’96 (P=0.01). , H. vernalis, on the other hand, showed a significantly higher population on DD in Spring ’95. The huge populations of found in Autumn ’96 proved not to be significantly different because of the enormous variability. As mentioned previously, the very high populations found on these two replicates were due to a recent sheep ‘camp’, which resulted in high levels of dung being present.

Cores

0

700

1400

2100

2800

3500

S pring 94 A utum n95 S pring 95 A utum n96 S pring 96

Abu

ndan

ce

Figure 31. Abundance of functional group E in each sampling period at Harden.

S pr ing 94

0

130

260

390

520

650

IC C

IIC C

IIIC C

IVC C

ID D

IID D

IIID D

IVD D

Abu

ndan

ce

A utum n 95

0

5

10

15

IC C

IIC C

IIIC C

IVC C

ID D

IID D

IIID D

IVD D

Abu

ndan

ce

S pr ing 95

0

50

100

150

IC C

IIC C

IIIC C

IVC C

ID D

IID D

IIID D

IVD D

Abu

ndan

ce

A utum n 96

0

500

1000

1500

2000

IC C

IIC C

IIIC C

IVC C

ID D

IID D

IIID D

IVD D

Abu

ndan

ce

S pr ing 96

0

140

280

420

560

700

IC C

IIC C

IIIC C

IVC C

ID D

IID D

IIID D

IVD D

Abu

ndan

ce

Figure 32. The abundance of springtails from functional group E from each treatment at Harden.

30

Summary The data clearly show that springtails respond to the treatments imposed at these sites, although background variation, due to climatic conditions, was very large. Generally speaking, DD and SI plots had increased numbers in both pitfalls and soil cores. Even when springtail numbers are normally high, i.e. cooler, moister periods, this difference was still evident (e.g. Figures 24, 27, 30). On such small plots, where there is considerable potential for immigration, and over such a short period, this differences were detectable. The greatest differences were shown by the poduromorph (e.g. B. platensis, H. vernalis)and isotomid (e.g. C. thermophilus, M. macrochaeta, F. onychiurina) groups and least (if any) by the entomobryids (e.g. E. unostrigata) and sminthurids (e.g. J. stachi). Generally, the first two groups are more strongly associated with soil-dwelling and the last two with surface living. It is more likely, however, that the last two groups are more tolerant generally of drier conditions and thus less dependent on high humidity. The genus Brachystomella, as a whole, is very sensitive to moisture and species are inactive when conditions are not moist (cf. Table 8). Differences between treatments may have been directly due to increased moisture holding capacity of DD soil. B. platensis is thought to be a bacterial and nematode feeder but, as 546 individuals were caught on CC and 1758 on DD, there was no evidence from this species of greater numbers of bacterial feeding springtails in CC. Although C. thermophilus is a fungal feeder, its primary response, in this situation, may have been to soil moisture. All species in the genus Mesaphorura are invariably soil-living and have grinding mouthparts, suggesting that they feed on fungi and possibly soil algae. They occur in humid soils, where they are often associated with roots. They are generally restricted to disturbed habitats. Under dry conditions, e.g. before autumn rains in April or in a drought, 80-nearly 100% of the fauna were found in the lower (0-5cm) layer of soil (Table 6). Under humid conditions the reverse distribution occured with up to 90% of the fauna found in the top (5-10cm) layer. The greatest proportion of fauna found in the top layers was under DD, as might be expected given the greater ground cover on this treatment. The greatest proportion of fauna found in the lower layer was on the SI plots. Again perhaps this is to be expected because of the higher amount of organic matter at the lower level. F. onychiurina was identified earlier as a potential indicator species (Figure 16). Folsomina is a small genus of currently 4 species but Greenslade (unpublished) revised the genus and described two new species. All species are parthenogenetic and occur in soil, often at depths of 10 cms or more. The genus has a pantropical distribution and is not normally found in cool temperate regions. Species are believed to feed on fungi, having well-developed grinding mandibular plates. F. onychiurina is currently considered native to Australia. Looking at the vertical distribution of this species at Cowra in Autumn ‘97 (Table 10), the data indicate that F. onychiurina • was adversely affected by ploughing, • occurred predominantly below 5cm but could occur higher in the soil profile if conditions

were suitable, and • appeared to be beneficially affected by increased organic matter at depth through stubble-

incorporation. The data suggest that this species could have some potential as an indicator of soil health.

31

Table 10. Effect of treatment on the vertical distribution of F. onychiurina specimens collected at Cowra (0-5cm/5-10cm). Current Treatment

Original treatment CC DD SI DD (1) 2/17 23/25 46/54 SI (2) 3/5 8/17 19/15 CC (3) 0/5 3/6 30/39

As mentioned earlier, the data for Feeding Group E demonstrate some of the problems that can be encountered in sampling soil fauna. The highly patchy distribution of hypogastrurids in Autumn ‘96 was clearly due to the presence of sheep dung on CC3 and CC4. Dung was almost certainly present in the four soil cores in which Hypogastrura were found in large numbers. However, this was not repeated in Spring ’96, although dung was certainly present on the same replicates. It is likely that the dung was generally more moist in Spring ’96, providing a good habitat for hypogasturids, whilst in Autumn ‘96, sampling took place during and after a much drier period and it is likely that dung moist enough to provide favourable habitat was rare and patchy. Other issues relating to these data on springtails will be discussed again later.

Mites

Abundance and Species Diversity A total of 67 species were identified from the Cowra site (Figure 39, Appendix 3). Whilst the overall value of the Simpson Index for the Cowra site was 0.89, it is worth pointing out that the most abundant species, Tyrophagus sp.,was more than three times as abundant as the next species (Tydeus sp.). When the treatments were split up, the Simpson Index showed considerable response to treatment, with the CC treatment being noticeably less diverse than the other two (Table 11). The lowest value was observed on CC1, which was originally DD. Interestingly, the two original CC treatments where management was changed (DD3 and SI3) showed substantial increases in diversity when compared to that which remained CC (Table 11). Those DD and SI treatments changed to CC showed reductions in the Simpson Index of a similar order.

32

1

10

100

1000

10000

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51 53 55 57 59 61 63 65 67

Species rank

Abu

ndan

ce

Figure 39. Species –abundance distributions for mites from Cowra. Table 11. Effect of treatment on the Simpson Index for mites at Cowra. Current Treatment


Looking at the total number of mites collected from soil cores in each treatment (Figures 40 and 41), it is readily apparent that the abundances from CC treatment at both sites are noticeably lower than for the other treatments. Analysis of variance confirms this (for Cowra, P=0.027; for Harden, P=0.003).

33

Originally Direct Drilled

0

500

1000

1500

2000

Spring94 Autumn95 Spring95 Autumn96 Spring96 Autumn97

Abu

ndan

ce

Originally Stubble-Incorporated

0

600

1200

1800

2400


Abu

ndan

ce

Originally Conventionally Cultivated

0

500

1000

1500

2000

2500


Abu

ndan

ce

Figure 40. Total number of mites collected from each treatment at Cowra at each sampling period. The white columns are the CC treatment, the striped columns the DD treatment and the black columns the SI treatment.

34

0

700

1400

2100

2800

3500


Tota

l col

lect

ed

Figure 41 Effect of treatment on the number of mites collected from Harden soil cores. White columns are the CC treatment, striped columns the DD treatment.

Trophic structure Species were classified into functional groups, based on existing information on the feeding biology of each species (after Luxton, 1972; Kethley, 1982; Walter, 1988). The classification reflected their role in the ecosystem and their contribution to soil processes. The classification differs from that of springtails in that no account is taken of the vertical distribution in the soil occupied by particular species. • Macrophytophage (T): feeding exclusively of higher plant material, although the majority

of species require their food to be somewhat softened and decayed by fungi. • Microphytophage (U): feeding on soil microflora of unknown specificity • Bacteriophage (V): feeding on predominantly on bacteria • Mycophage (W): feeding on predominantly on fungi • Panphytophage (X): feeding on all of the above and/or detritus • Predator (Y): feeding on living animal material • Parasite (Z) Dividing the mites collected from Cowra into these functional groups, there was a reasonably even spread amongst the functional groups, with the exception of the macrophytophages, which constituted only about 2% of the mites collected (Table 12). When these data were broken up by sampling period (Table 12), a slightly different picture emerged. The proportion of predators was fairly consistent over the six samples, as were the microphytophages and mycophages. In contrast, the panphytophages and bacteriophages showed two distinct patterns. During the dry periods (Spring ’94, Autumn ’95 and Autumn ’96) bacteriophages were the largest component of the mite fauna whereas in the moister periods, the panphytophages became dominant. Macrophytophages were really only apparent in the first two periods. Table 12. Functional composition (% of total) of the mite fauna from soil cores at Cowra

Functional group Overall Spring ‘94

Autumn ‘95

Spring ‘95

Autumn ‘96

Spring ‘96

Autumn ‘97

Microphytophage 25 16 14 31 17 27 27Predator 11 12 8 15 9 13 10

Mycophage 14 22 11 10 16 17 9Panphytophage 31 21 11 36 16 34 43

Macrophytophage 2 7 19 2 3 0 0Bacteriophage 17 22 37 6 39 9 11

35

Macrophytophage This group was comprised of 8 species, the most abundant of which was a species of Tetranychus (Prostigmata;) (Figure 43). With the exception of Autumn ’95, this group generally constituted less than3% of the mite community. Analysis of variance failed to show any significant effects of treatment (P=0.64).

0

60

120

180

Tetranychus sp. Halotydeus sp. Eriophyidae Tetranychidae sp. Ledermuelleriasp.

Halotydeusdestructor

Lorryia sp. Brevipalpus sp.

Abu

ndan

ce

Figure 42. Species abundance within macrophytophage mites at Cowra

0

60

120

180


Abu

ndan

ce

Figure 43. Abundance of macrophytophage mites in each sampling period at Cowra.

36

Spring 94

0

10

20

30

40


Ab

und

ance

Autumn 95

0

5

10

15

20

25

30

35


Ab

und

ance

Spring 95

0

10

20

30

40

50


Abu

nda

nce

Autumn 96

0

30

60

90


Abu

nda

nce

Spring 96

0

2

4

6

8

10


Abu

ndan

ce

Autumn 97

0

1

2

3

4

5


Abu

ndan

ce

Figure 44. The abundance of macrophytophage mites from each treatment at Cowra. Microphytophage This was a relatively diverse group of mites, with 14 species showing reasonable levels of abundance (Figure 45). Abundances generally increased during the study period (Figure 46). Overall, analysis of variance produced a very significant result (P=0.0004), with the CC1 treatment showing significantly lower levels of this group compared to all of the DD treatments and to SI3. The four most common species were looked at individually. These were: Oppiella nova, Eupodes sp., Tectocepheus velatus and Microppia minus. For O. nova, analysis of variance suggested that CC1 was significantly lower than either DD3 or SI3 (P=0.011). O. nova is a cosmopolitan species and one of the most common oribatid species in the world. It is probably the most abundant oribatid associated with cultivated soil. For the Eupodes sp., the significance level was 0.03, but no significant individual treatment differences could be found (Figure 47). With M. minus, the analysis of variance failed to show any significant difference (P=0.12). M. minus is a cosmopolitan species, though it usually occurs in far lower densities than O. nova. Very little is known about its biology, although it appears to exhibit a preference for mineral soils rather than litter layers (Luxton, 1981b). Finally, T. velatus was shown to be extremely responsive to the treatments (P=0.0004). Analysis of variance showed that DD1 had significantly higher populations than any of the

37

CC treatments and that DD3 was significantly higher than CC1 (Figure 47). This is another cosmopolitan species that appears to exhibit a preference for cultivated soils. In temperate, northern hemisphere habitats, two annual density peaks for this species have been reported, coinciding with the peaks of maximum rainfall (summarised by Luxton, 1981a) and it is usually confined to the top 0-3 cm of soil. It would appear that this species thrives in cool, damp conditions. Generation time is approximately 1 year depending on microclimate and food.

0

500

1000

1500

2000

Opp

iella

nov

a

Eup

odes

sp.

Tect

ocep

heus

vela

tus

Mic

ropp

ia m

inus

Ben

oiny

ssus

sp.

Mul

tiopp

ia s

p.

Tect

ocep

halu

sve

latu

s sp

.

Bra

chyc

htho

nius

sp.

Epi

lohm

anni

apa

llida

Suc

tobe

lba

nond

ivis

a

Gra

ptop

pia

sp.

Pro

tere

unet

es s

p.

Dis

copp

ia s

p.

Bra

scop

pia

sp.

Suc

tobe

lba

sp.

Vep

raca

rus

sp.

Opp

iidae

sp.

Tota

l col

lect

ed p

er s

peci

es

Figure 45. Species abundance within microphytophage mites at Cowra.

0

600

1200

1800


Abu

ndan

ce

Figure 46. Abundance of microphytophage mites in each sampling period at Cowra.

38

Spring 94

0

15

30

45


Ab

unda

nce

Autumn 95

0

5

10

15

20


Abu

ndan

ce

Spring 95

0

100

200

300

400


Abu

ndan

ce

Autumn 96

0

50

100

150

200


Abu

nda

nce

Spring 96

0

170

340

510


Abu

ndan

ce

Autumn 97

0

80

160

240

320


Abu

ndan

ce

Figure 47. The abundance of microphytophage mites from each treatment at Cowra. Plots of the relative abundance over time of the three species showing significant responses, for each of the treatments, revealed subtle differences in their responses to the treatments (Figure 48). Eupodes sp. failed to show any consistent pattern of response, although the DD2 treatment seemed to favour this species more than the other two original SI treatments. With O. nova, DD was generally more favourable than either of the other treatments and the CC was generally the worst. T. velatus showed by far the most consistent response, with the three DD treatments all showing rises over the study period. The CC treatments showed uniformly low numbers of this species.

39

Oppiella - Original DD

0

1

2

3

4

5

Spring'94

Autumn'95

Spring'95

Autumn'96

Spring'96

Autumn'97

Abundance

Oppiella - Original CC

0

5

10

15

Spring'94

Autumn'95

Spring'95

Autumn'96

Spring'96

Autumn'97

Abundance

Oppiella - Original SI

0

2

4

6

8

Spring'94

Autumn'95

Spring'95

Autumn'96

Spring'96

Autumn'97

Abundance

Eupodes - Original DD

0

1

1

2

2

Spring'94

Autumn'95

Spring'95

Autumn'96

Spring'96

Autumn'97

Abundance

Eupodes - Original SI

0

2

4

Spring'94

Autumn'95

Spring'95

Autumn'96

Spring'96

Autumn'97

Abundance

Eupodes - Original CC

0

2

4

Spring'94

Autumn'95

Spring'95

Autumn'96

Spring'96

Autumn'97

Abundance

Tectocepheus - Original DD

0

1

2

3

4

5

Spring'94

Autumn'95

Spring'95

Autumn'96

Spring'96

Autumn'97

Abundance

Tectocepheus - Original SI

0

1

2

3

4

Spring'94

Autumn'95

Spring'95

Autumn'96

Spring'96

Autumn'97

Abundance

Tectocepheus - Original CC

0

2

4

6

Spring'94

Autumn'95

Spring'95

Autumn'96

Spring'96

Autumn'97

Abundance

Figure 48. Effect of treatment upon the abundance of three key species of microphytophage mite at Cowra. The solid line depicts the new DD treatments; the dashed line depicts the new CC treatments; the dotted line depicts the new SI treatments.

40

Bacteriophage This group was represented by just 5 species, the most common of which were a Tydeus species and a Speleorchestes species (Figure 49). Abundance was generally moderate, with only Autumn ’96 showing substantial numbers (Figure 50). Analaysis of variance indicated that there were significant differences between treatments for the group as a whole (P=0.04), although no specific contrasts were apparent (Figure 51).

0

600

1200

1800

2400

Tydeus sp. Speleorchestes sp. Nanorchestes sp Coccotydeolus sp. Tydeidae sp.

Abu

ndan

ce

Figure 49. Species abundance within bacteriophage mites at Cowra.

0

600

1200

1800

2400


Abu

ndan

ce

Figure 50. Abundance of bacteriophage mites in each sampling period at Cowra.

41

Spring 94

0

25

50

75

100


Abu

ndan

ceAutumn 95

0

13

26

39

52


Abu

ndan

ce

Spring 95

0

30

60

90


Abu

ndan

ce

Autumn 96

0

175

350

525

700

DDI S II CCI DDII S III CCII DDIII S IIII CCIIIA

bund

ance

Spring 96

0

30

60

90

120


Abu

ndan

ce

Autumn 97

0

50

100

150


Abu

ndan

ce

Figure 51. The abundance of bacteriophage mites from each treatment at Cowra.

Original DD

0

10

20

30


Abu

ndan

ce

Original SI

0

3

6

9


Abu

ndan

ce

Original CC

0

2

4

6


Abu

ndan

ce

Figure 52. Effect of treatment upon the abundance of a Tydeus species of bacteriophage mite at Cowra. The solid line depicts the new DD treatments; the dashed line depicts the new CC treatments; the dotted line depicts the new SI treatments.

42

The two most common species were examined more closely and, whilst the Speleorchestes species failed to show any significant effect, the Tydeus species did (P=0.012). The DD1 treatment was shown to have significantly greater abundance of Tydeus than the CC2 and CC3 treatments. The most interesting aspect of the response of this species was the fact that the highest abundances were observed in the DD and SI treatments in Autumn ’96, when conditions were dry (Figure 52).

Mycophage This was a very diverse group containing 16 species, the most abundant of which were two species of Bakerdania (Figure 53). This group was generally present in modest numbers but was relatively common in Autumn ’96 and Spring ’96 (Figure 54). Analysis of variance failed to detect any significant effect of treatment (P=0.95) (Figure 55). Even when data for the two most common species were analysed, this pattern persisted (Bakerdania “Big”, P=0.76; Bakerdania “Small”, P=0.99).

0

300

600

900

1200

Bak

erda

nia

"Big

"

Bak

erda

nia

"Sm

all"

Tars

onem

us s

p.

Uro

podi

dae

sp.

Bak

erda

nia

"Elo

ngat

e"

Scu

taca

rus

sp.

Dol

icho

cybe

sp.

His

tiost

oma

sp.

Terp

naca

rus

sp.

Bak

erda

nia

"Squ

at"

Cal

volia

sp.

Aca

rus

sp.

Lepi

dogl

yphu

ssp

.

Lohm

aniid

ae s

p.

Aly

cosm

esis

sp.

Gly

cyph

agid

aesp

.

Abu

ndan

ce

Figure 53. Species abundance within mycophage mites at Cowra.

0

300

600

900

1200

S pring '94 A utum n '95 S pring '95 A utum n '96 S pring '96 A utum n '97

Abu

ndan

ce

Figure 54. Abundance of mycophage mites in each sampling period at Cowra.

43

S p r in g '94

0

3 0

6 0

9 0

D D I S II C C I D D II S III C C II D D III S IIII C C III

Abu

ndan

ce

Au tu m n '95

0

4

8

12

16


Abu

ndan

ce

S p r in g '95

0

4 0

8 0

1 2 0


Abu

ndan

ce

Au tu m n '96

0

1 0 0

2 0 0

3 0 0


Ab

unda

nce

S p r in g '96

0

9 0

18 0

27 0

36 0


Abu

nda

nce

Au tu m n '97

0

40

80

1 20


Abu

ndan

ce

Figure 55. The abundance of mycophage mites from each treatment at Cowra. Panphytophage This abundant group is comprised of nine species, but is dominated by Tyrophagus sp., a cosmopolitan genus of soil and stored products (Figure 56). The group shows an identical pattern to the springtails in Functional Group D (Figure 14), with abundance generally increasing with time (Figure 57). Analysis of variance failed to detect any significant effect due to treatment (P=0.2) (Figure 58). When analysed separately, Tyrophagus sp gave a similar result (P=0.53)

0

1600

3200

4800

6400

Tyrophagus sp. Antarctozetessp.

Zygoribatulacf.longispora

Ceratozetidaesp.

Galumna sp. Brasilozetessp.

Zygoribatula sp"gracile"

Oribatidae sp. Oripodidae sp.

Abu

ndan

ce

Figure 56. Species abundance within panphytophage mites at Cowra.

44

0

500

1000

1500

2000

2500


Abu

ndan

ce

Figure 57. Abundance of panphytophage mites in each sampling period at Cowra.

Spring '94

0

0.25

0.5

0.75


O /

P

Autumn '95

0

0.1

0.2

0.3


O /

P

Spring '95

0

0.5

1

1.5

2


O /

P

Autumn '96

0

0.15

0.3

0.45


O /

P

Spring '96

0

0.5

1

1.5

2


O /

P

Autumn '97

0

1

2

3

4


O /

P

Figure 58. The abundance of mycophage mites from each treatment at Cowra.

45

Predator This was by far the most diverse group at this site, containing 30 species. Many of these, however, were present in very low numbers and found only occasionally. Only 5 species were recorded regularly (Figure 59). The abundance data suggested that there might be a Spring/Autumn cycle over which the effects of climatic conditions were overlayed (Figure 60). More data are required to determine whether or not this is the case. Taken overall, the data for this group failed to show any significant response to treatment (P=0.42) (Figure 61). When considered separately, both Alicorhagia sp. (P=0.62) and Javieroppia cervus (P=0.08) also failed to achieve significance. Alicorhagia sp. was relatively abundant in all three of the more humid periods whilst J. cervus was only abundant in Spring ’95 and then only on DD1 and SI2, the original DD and SI treatments.

0

200

400

600

800

Alic

orha

gia

sp.

Mes

ostig

mat

id s

pp.

Javi

eopp

ia c

ervu

s

Asc

a sp

.

Mes

ostig

mat

id s

p.1

Arc

tose

is c

erat

us

Hyp

oasp

is s

p.

Lael

apid

ae s

p.D

Stig

mae

us s

p.

Cun

axoi

des

sp.

Vei

gaid

ae s

p.

Olo

gam

saus

sp.

Bde

llida

e sp

.

Neo

cuna

xoid

es s

p.

Bde

lla s

p.

Coc

corh

agid

ia s

p.

Rha

gidi

idae

sp.

Pro

toga

mas

ellu

ssp

.

Ery

thro

ccar

us

Cun

axid

ae s

p.

Stig

mae

idae

sp.

Cry

ptog

natu

sla

teop

unct

atus

Any

sttis

sp.

Aly

cus

sp.

Par

asiti

dae

sp.

Ery

thra

eida

e sp

.

Lael

aps

sp. 1

Rha

gidi

a sp

.

Per

gam

asus

sp.

Par

atyd

eus

sp.

Abu

ndan

ce

Figure 59. Species abundance within predatory mites at Cowra

0

210

420

630

840


Abu

ndan

ce

Figure 60. Abundance of predatory mites in each sampling period at Cowra.

46

Spring '94

0

8

16

24

32


Ab

und

ance

Autumn '95

0

6

12

18


Ab

unda

nce

Spring '95

0

100

200

300


Abu

nda

nce

Autumn '96

0

50

100

150


Ab

und

ance

Spring '96

0

50

100

150


Ab

und

acn

e

Autumn '97

0

35

70

105

140


Abu

ndan

ce

Figure 61. The abundance of predatory mites from each treatment at Cowra. Parasite Only 11 parasitic mites were collected over the entire 3-year period. Of these, 9 were a species of Leptus (Prostigmata). No further comment on this group is warranted. Summary The data clearly show that mites responded to the treatments imposed at these sites, although background variation, due to climatic conditions, was very large (Figures 40, 41). Generally speaking, DD and SI plots had increased abundance in both pitfalls and soil cores. Whereas all springtail species showed low abundances under dry conditions, many mite groups were very abundant in Autumn ’96, a dry period. This is highlighted in Figures 43/44, 50/51, 54/55 and 60/61. In all cases the SI and particularly the DD treatments provided the highest abundances. Further work is needed to understand the nature of this response.

47

T. velatus showed the most significant response to the treatments at Cowra (Figure 48). As mentioned previously, this is a cosmopolitan oribatid species that appears to exhibit a preference for cultivated soils. The data indicated that T. velatus, like F. onychiurina, • was adversely affected by ploughing, • appeared to be beneficially affected by increased organic matter at depth through stubble-

incorporation. The data suggested that this species could be a potential indicator of soil organic matter levels in soil. Other issues relating to these data on mites will be discussed later.

Other insects

Ants Ants were probably the most obvious group on the Cowra site and are remarkably prolific in Australia generally. They are very difficult to collect reliable population data on, due to their territoriality and pitfall trapping is a somewhat hit-and-miss activity because it assumes random movement by the organisms. Catches are also dependent upon activity, which may well be weather-driven. Nevertheless, the ant fauna (not split up into species groups) showed a very marked response over the duration of the study, declining steadily (Figure 62). Despite this, analysis of variance on the Cowra data failed to show any significant response to treatment (P=0.35) and it is not clear why this trend should have occurred. A somewhat different picture was found at Harden, where there appeared to be a Spring/Autumn cycle, but the differences were also not significant (P=0.24 (Figure 63). Populations were highest in the drier periods., contrary to all other groups and lowest in the moist Spring ‘96. Whatever the explanation, such a change in abundance of what is a very important predator could have had a significant effect upon a number of taxa, including the above-ground and surface-dwelling springtails. It is instructive to look at the distribution of two of the more common species of above-ground springtails, J. stachi and H. manubrialis, which were present at the Cowra site in very high numbers in Spring ’95 and more modest numbers in Spring ’96. They were only in low numbers in the very dry Spring ’94 (Table 13). From this, one can see that the treatment that had the highest catch of ants (DD1) also had the lowest catch of H. manubrialis and second lowest catch of J. stachi. The treatments with the lowest numbers of ants (CC1, CC2, and CC3) also showed the highest levels of these two species of springtail. Set against this, there was evidence, from another sampling period, of simultaneously high numbers of these springtails and ants. The explanation for this seemed to be that this coincided with high populations of aphids, which constituted a very obvious alternative prey. One must not make too much of the Spring ’95 observations because this was but one of the five sampling periods. The other sampling periods did not show such interesting patterns. Nevertheless, there is an indication of a complex relationship between weather, tillage and stubble-management practices and the relative abundances of a polyphagous predator and one or two species of prey. These relationships are worthy of further investigation.

48

0

40

80

120


Ave

rage

abu

ndan

ce p

er tr

ap p

er d

a

Figure 62. The abundance of ants collected in pitfall traps at Cowra.

0

2

4

6

Spring 94 Autumn 95 Spring 95 Autumn 96

Ave

rage

abu

ndan

ce p

er tr

ap p

er d

ay

Figure 63. The abundance of ants collected in pitfall traps at Harden. White columns are the CC treatment, striped columns the DD treatment.

Table 13. The numbers of Jeannenotia stachi, Hypogastrura manubrialis and ants collected in pitfall traps at Cowra in Spring ‘95. Treatment Sample DDI SII CCI DDII SIII CCII DDIII SIIII CCIIIJeannenotia stachi

302 1055 1018 1345 1143 3506 194 1184 976

Hypogastrura manubrialis

18 37 801 831 124 58 688 596 2719

Ants 331 103 40 91 181 61 164 73 65

Insect larvae The last group of fauna collected during the study was called “Insect larvae” and represented a mixture of various taxa but seemed to dominated by Diptera. The data from Cowra are quite variable (Figure 64) and analysis of variance did not detect any significant response to treatment

49

(P=0.27). The data collected from the soil cores at Harden, however, show a somewhat different picture (Figure 65) and analysis of variance showed that there were significantly more larvae collected from the DD treatment than from the CC treatment (P=0.03).

O r i g i nal l y D i r e c t D r i l l e d

0

30

60

90


Abu

ndan

ce

O r i g i nal l y Stubbl e -Inc o r po r ate d

0

5

10

15

20

25


Abu

ndan

ce

O r i g i nal l C o nve nti o nal l y C ul t i vate d

0

5

10

15

20

25


Abu

ndan

ce

Figure 64 The abundance of insect larvae collected from each treatment at Cowra. The white columns are the CC treatment, the striped columns the DD treatment and the black columns the SI treatment.

50

0

50

100

150

200

250


Tota

l col

lect

ed p

er tr

eatm

ent

Figure 65 The number of insect larvae collected from each treatment at Harden. The white columns are the CC treatment, the striped columns the DD treatment. As the taxonomic composition of this group is unknown and likely to be varied, no further analysis or discussion is warranted.

51

Discussion

Diversity and abundance This investigation clearly shows that the arthropod fauna present in agricultural soils in south-eastern Australia is abundant and diverse, both systematically and ecologically. The study at Cowra and Harden is the first comprehensive systematic survey, so it is not surprising that many new taxa were found. Many of the known taxa are cosmopolitan species, which are frequently found associated with arable agriculture and have probably been dispersed with crops. Many of the previously unknown mite taxa are probably native species, because the mite fauna of Australia is relatively poorly known. The large number of previously unknown, and possibly native, species demonstrate that caution is necessary when applying results from overseas to situations in Australia. This should be noted in reading the discussion that follows. The data presented above demonstrate that certain agricultural practices do affect the diversity and abundance of soil fauna. If one combines the species-level data for the two major groups studied, mites and springtails, the Simpson Indices show marked responses to treatment, with the CC treatment being noticeably less diverse than the other two (Table 14). The lowest value was observed on CC3, which was originally CC. Interestingly, the other two original CC treatments, where management was changed (DD3 and SI3), showed substantial increases in diversity when compared to that which remained CC (Table 14). Those DD and SI treatments changed to CC showed reductions in diversity of a similar order.

Table 14. Simpson’s Indices for the combined species –abundance data for springtails and mites from Cowra. Current Treatment


Changes in total abundance between sampling times were strongly related to soil moisture levels and, where this was high, treatment effects were often masked. Differences in total arthropod abundance between tillage treatments resemble results from other places. The results are generally consistent with observations that there is lower biological activity in soils that have been cultivated (Coleman & Crossley 1996, Didden et al. 1994, Werner & Dindal 1990).

Soil ecology and management The differences in diversity, abundance and trophic structure between soil depths, times of sampling, sites, and tillage treatments have major implications for soil processes. They influence interpretation of the effects of tillage treatments on the soil system as a whole. The differences in the arthropod fauna are both the result of changes in other components, and the cause of changes in other parts of the system. Data for such investigations is required from concurrent detailed studies by specialists in these other fields. Studies on soil properties and soil arthropod fauna at Cowra and Harden have been conducted but, as these studies will be completed subsequent to submission of this report, detailed discussion of the

52

relationships of the soil arthropods to these other components of the soil system is not possible at present. Nevertheless, it is valuable to consider some of their interim findings. The study that looked at the impact of tillage practices on the soil microbiota and soil properties (CSO 6A) found significant differences between the sites that may explain some of the differences in the soil fauna observed in the present study. The total carbon content of the soils at these sites were quite different and also between treatments at each site. The upper 5 cm of soil in the DD treatments at Cowra and Harden had values of 1.02 and 1.86%, respectively, whilst the 5-10cm level had 0.75 and 1.04%. The equivalent vlaues for the CC treatments were 0.58 and 1.51% for 0-5cm and 0.57 and 1.24% for 5-10cm. The SI treatment at Cowra was intermediate, with a value of 0.79% for both levels. Turning to the microbiota, this parallel study found that populations of all microorganisms, including root diseases, such as Pythium, were highest in the DD and SI treatments.In contrast,the Harden site showed higher levels of bacteria and actinomycetes in the CC treatment but higher levels of cellulose-decomposing microorganisms and fungi in the DD treatment. From this it can be concluded that stubble retention favours the build up of microbial populations, especially fungi and cellulose decomposers. Fungi are also encouraged by direct-drilling. Some interesting effects of change in tillage practice were found at Cowra. Changing from DD to SI resulted in a significant increase in microbial biomass and CO2-C respiration, presumably due to the increased availability of stubble residues to the soil microbiota. Changing from SI or TT to DD also increased both microbial biomass and CO2-C respiration. This suggests that there were two interacting parameters governing microbial activity, namely residue retention and tillage and it is becoming clear that reduced tillage with residue retention is conducive to the development of high microbial biomass and microbial activity. Another interesting observation is that these rapid changes brought about by changes in tillage practice occur more in the surface soil (0-5 cm) than at depth (5-10 cm). Shifts in abundances of functional groups were detectable but were not dramatic. There was a noticeable decline in fungi (including the root pathogen Pythium) in the DD and SI treatments that became CC treatments (CC1 and CC2) but there was also a small increase in the abundance of cellulolytic bacteria and fungi.This would have been due to the deeper incorporation of crop stubble as a result of tillage. In contrast, there is an increase in fungi in the CC treatments that became DD and SI. These shifts are not unexpected and arise from the response of the individual functional groups to the degree of soil disturbance. Generally, bacteria are favoured by increased disturbance whilst fungi benefit from reduced disturbance. Two processes are probably most important in evaluating the implications of observed differences in trophic structure. First, abundance of mycophagous and bacteriophagous species is critical because feeding on soil fungi and bacteria is very important for carbon and nutrient flows in soil (Anderson 1988, Brussard et al.1990, Hassink et al.1993). Even relatively small changes in the abundance or activity of this trophic group can cause large changes in carbon and nutrient fluxes, and hence availability to plants (Beare et al. 1989, Brussard 1994, Hunt et al. 1987, Wright et al.1989). Many studies have shown that it is turnover, rather than amount of biomass, which is most important in mobilizing nutrients and energy (Anderson 1988, Coleman & Crossley 1996, de Ruiter et al. 1994, Verhoef & Brussard 1990).

53

The second process important in evaluating the consequences of differences in arthropod trophic structure observed at Cowra and Harden is fungal immobilization of nutrients and energy. Fungal decomposition of organic materials is often slower than bacterial decomposition, resulting in immobilization (Doran 1980, Hendrix et al. 1986). However, consumption by mycophagous soil fauna will mobilize the materials in the fungal biomass. The results presented here suggest that movement of energy and nutrients through the bacterial pathway may be relatively greater under CC, and movement through the fungal pathway may be relatively greater under DD and SI. This is opposite to the conclusion reached in the parallel study that looked at the nematode fauna of these sites (CSE73A). This apparent anomaly highlights the need for studies to determine the flow of energy and nutrients through such agricultural systems. The difference in depth distribution between tillage treatments has important implications. Not only is total abundance lower under CC, but distribution is concentrated in the lower layers of soil. Under SI, total abundance was similar to DD, but arthropods were more concentrated near the surface. One effect of CC is to bury organic matter, where it undergoes decomposition by different organisms than when it is on the surface (Beare et al.1993, Neely et al. 1991). The proportion of decomposition attributable to fungi can be greater at depth than on the surface under some conditions (Beare et al. 1993), although this is not always so (Neely et al. 1991).

Use as indicators Low abundance of Oribatida compared with Prostigmata was first noted by Edwards and Lofty (1969) as characteristic of long-term cultivated soils, and has been confirmed by many subsequent authors. The phenomenon is associated with the amount of organic matter in the soil; oribatid mites being generally more abundant in soils of high organic matter and high cellulose decomposition rates. The ratios of oribatid to prostigmatid mites extracted from soil cores at Cowra are shown in Table 15. Analysis of variance of the overall performance of this ratio failed to show any significant response to treatment (P=0.07), although if the Spring ’96 data are removed, where CC2 is abnormally high, a significant difference can be demonstrated (P=0.03). There are several interesting points that emerge from these data: • The ratio is very low in the drier periods (Spring ’94, Autumn ’95 and Autumn ’96), confirming

the general point that oribatid mites do better in more humid environments. • The CC treatments, especially CC1, generally show the lowest values for this ratio, implying

that aspects of the conventional cultivation regime are detrimental to oribatid mites. • The DD treatments generally show the highest values for this ratio and, in Autumn ’97, show

the highest values observed during the study.

54

Table 15. The ratio of oribatid to prostigmatid mites at Cowra. Figures in bold indicate situations where oribatids outnumber prostigmatids. Figures in italics indicate situations where the ratio is between 0.5 and 1,0.

Treatment

Sample DD1 SI1 CC1 DD2 SI2 CC2 DD3 SI3 CC3 Spring '94 0.73 0.56 0.09 0.18 0.47 0.08 0.08 0.11 0.08 Autumn '95 0.29 0.14 0.00 0.08 0.04 0.17 0.27 0.18 0.12 Spring '95 0.79 0.40 0.09 0.85 1.63 0.52 1.98 0.90 0.77 Autumn '96 0.15 0.11 0.06 0.13 0.42 0.26 0.35 0.25 0.15 Spring '96 0.89 0.59 0.29 1.21 0.43 1.79 0.52 0.26 0.61 Autumn '97 2.14 0.38 0.07 2.00 1.61 0.43 3.80 0.99 0.72 In an effort to explain the cause of the dramatic changes in the value between the drier and more humid periods, it is instructive to look at the changes in numbers of the more common oribatid species. By far the most common species is O. nova (Figure 48). This is present in substantial numbers in all three of the more humid periods, but especially so in Spring ’95. In Spring ’96, M. minus is also present in substantial numbers. In Autumn ’97, both species are relatively abundant but it is T. velatus that is largely responsible for the very high values of the ratio (Figure 48). It is possible that the higher ratios may reflect a more active (fungal-driven) decomposition, although none of the above mentioned species are strictly mycophagous. The predatory oribatid, J. cervus, is an interesting species, first recorded from ploughed fields outside Madrid, Spain. All previous records are from Spain. It may well be introduced to Australia. Its nematophagous habit was determined from observations on gut contents during the course of this project. Whilst the analyses of variance failed to show any significant effects of treatment, the result was marginal and further sampling could show this species, as a predator of nematodes, to be a useful indicator of changes in the soil biota. From the data presented above, it is apparent that elements of the rich and diverse soil fauna do have the potential to serve as indicators of management-induced change in the soil. In particular, springtails from the functional group D, the euedaphic fungal feeders, and certain microphytophage mites showed marked responses to treatment. The most promising species would seem to be F. onychiurina and T. velatus, which showed marked and reasonably consistent responses. The indicators suggested by the present study require testing on independent data sets, preferably in a range of different soil types, climates and geographic locations. Such data are essential for the development of robust measures of soil biological properties. Several general results from Cowra and Harden are relevant to the practicalities of using key groups of soil arthropods as indicators of soil processes. First, there are large numbers of species, genera and higher taxa present, meaning that correct identification is a critical step in using any indicator taxa. Tools for this are currently lacking, but the taxonomic knowledge gained during this study constitutes a valuable resource for identification that should be consolidated and put into an accessible format if possible. This is referred to again in the Recommendations section. The second important result is the speed with which responses to changes in tillage practices were detected in the arthropod community. Changed tillage treatments at Cowra were applied just before

55

sampling started, yet the differences in some components of the arthropod fauna, especially F. onychiurina and T. velatus, were detectable after just 18 months.

56

Conclusions The objectives of this investigation have been met in the following ways. 1. A total of 33 springtails and 67 mite taxa were identified, mostly to species. Many new and

undescribed species were found, as well as new records for Australia. The taxa were allocated to ecological functional groups, based on existing knowledge. The abundances of all the taxa were assessed. Possible relationships between abundance of each trophic group and soil biological processes were discussed.

2. Differences between CC, DD, and SI tillage treatments in the diversity and/or abundance of

most trophic groups were found. Together, these differences showed a trophic shift toward fungal-feeding under the DD and SI treatments. The number of species present was comparable to the numbers found in highly productive agricultural systems elsewhere in the world.

3. Different characteristics of arthropod community were related to soil properties and so were

useful as indicators in different ways. The ecological processes underlying the observations on arthropod distribution and the interrelationships with other components of the soil system were discussed. Finally, an assessment of the implications of this research and recommendations for further investigations are presented.

57

Implications This study makes a valuable contribution to the issue of sustainable agriculture by highlighting the potential of this important component of the soil biota to indicate change within the soil ecosystem. It is the first comprehensive study of the major groups of soil arthropod fauna of an Australian agricultural soil to species level and, as such, raises many new questions and suggests several avenues for further research. Studies to fully confirm the present results and expand their generality to other situations are required. Notwithstanding the provisos on interpretation, this study has three major implications. First, there can be substantial differences in the major components of the arthropod fauna under different tillage practices, which probably reflect other components of the soil biota as well. These differences, plus those between different locations, suggest that the potential exists to manage the soil fauna in agricultural systems in Australia. The system parameters to be aimed for, in terms of diversity, abundance, trophic structure and species composition, may be unclear as yet, but there are now basic data indicating that such research is feasible, and indications of potentially profitable directions to explore. Second, inputs of carbon and nutrients to the soil, as residues and stubble, should be matched with likely decomposition pathways and depth profiles under different tillage practices. Such matching is likely to increase energy and nutrient turnover rates in soil and increase productivity, particularly under DD. More detailed information on most parts of the decomposition pathways in soil are required to facilitate this. Third, studies on soil arthropods can add a great deal to investigations of soil biological processes. With the wider availability of appropriate identification tools, several different groups of soil arthropods have the potential for use as biological indicators of change in soils.

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Recommendations 1. Further analyses This study has produced a large amount of data, some of which could not be analysed or included in this report, due to time constraints. In particular, the complexity of the mite fauna found in the cores from Cowra prevented a full analysis being carried out on the Harden data. This will be completed before publication of the results. Also remaining to be analysed are the correlations between soil arthropods and other biotic and abiotic factors in the soil system. When the data from the parallel studies become available, interrelationships among the various taxa or ecological groupings, and between the taxa or groups and soil parameters can be analysed. 2. Interactions of soil arthropods with other biota and soil It is essential to develop an understanding of the feeding relationships between and within the various functional faunal groups and how these vary with season, weather and management. Current methods of determining such feeding relationships include gut content analysis (using immunology, microscopy, radiology, or electrophoresis), direct observation of feeding, or inference from morphology of mouth parts. However, these methods are variously slow, laborious and/or potentially misleading and often cover only a limited range of potential "food taxa”. DNA probe technology has the potential to address all of these problems and provide a quantum leap in the ability to identify the feeding interactions between the invertebrate fauna within the soil. A proposal to pursue this research is in preparation. The development of such food webs would further advance the prospect of managing the cycling of nutrients within soil ecosystems for maximum productivity, sustainability and suppression of pests. 3. Consolidation and dissemination of systematic knowledge All of the above extensions of research in this area depend on accurate application of systematic knowledge. The specimens and systematic knowledge gathered as an essential part of the studies at Cowra and Harden are an important basic resource for this. We propose the development of a user-friendly, interactive, multimedia computer identification system for the major groups of soil organisms, which would include detailed information on the biology of the organisms, as well as illustrations and video images, where applicable. This will allow non-specialists to identify and retrieve information about major indicator groups of the soil fauna. We will provide additional information on topics such as biodiversity assessment, techniques for collection, preservation and identification. The system will provide a comprehensive guide to the fauna of Australian soils that will be suitable for users at various levels of expertise including farmers, extension workers, consultants, government agencies, Landcare groups, biologists, and importantly, schools and colleges, in order to target the next generation of farmers. By so doing, we seek to promote and encourage the development of soil biology for utilisation in sustainable agriculture. Funding is being sought for such a proposal to deliver the system in both CD-ROM and handbook formats.

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Appendices

Appendix 1 Details of activities on study sites at Cowra during the study period Date Conventional Cultivation Direct Drill Stubble Incorporation 1995 April worked with o/s discs May Sprayed 2.1 I / ha sprayseed Sprayed 1l roundup, 20grams

Glean 500mls 24D ester / ha Sprayed 1l roundup, 20grams Glean 500mls 24D ester / ha

Sprayed 1l roundup, 20grams Glean 500mls 24D ester / ha

sown wheat 42kg Dollarbird 100kg DAP Full Disturbance sowing

sown wheat 42kg Dollarbird 100kg DAP

sown wheat 42kg Dollarbird 100kg DAP Full Disturbance sowing

December harvest harvest harvest 1996

March sprayed 1l roundup, 1l surpass(24D) / ha

sprayed 1l roundup, 1l surpass(24D) / ha

sprayed 1l roundup, 1l surpass(24D) / ha

burnt stubble May spread 300 kg/ha Gypsum spread 300 kg/ha Gypsum spread 300 kg/ha Gypsum worked with scarifer and

harrows stubble incorporate o/s discs

rolled cambridge roller sprayed 1l/ha Sprayseed rolled cambridge roller sprayed 2.5l treflan, 1l

roundup, spread 100kg urea and sowed 4kg Oscar Canola & 125kg DAP fertiliser / ha

sprayed 2.5l treflan, 1l roundup, spread 100kg urea and sowed 4kg Oscar Canola & 125kg DAP fertiliser / ha

sprayed 2.5l treflan, 1l roundup, spread 100kg urea and sowed 4kg Oscar Canola & 125kg DAP fertiliser / ha

June sprayed 250 ml Fusilade and 100 mls Lemat /ha

sprayed 250 ml Fusilade and 100 mls Lemat /ha

sprayed 250 ml Fusilade and 100 mls Lemat /ha

August sprayed 250 ml Select and applied 100kg urea /ha

sprayed 250 ml Select and applied 100kg urea /ha

sprayed 250 ml Select and applied 100kg urea /ha

December harvest harvest harvest 1997

February sprayed 1.2l roundup, 2l Surpass

sprayed 1.2l roundup, 2l Surpass

sprayed 1.2l roundup, 2l Surpass

March worked o/s discs worked o/s discs April coolamon harrow Canola

stubble

worked o/s discs worked with o/s discs sprayed 1l roundup, 20 gms

Glean sprayed 1l roundup, 20 gms Glean

sprayed 1l roundup, 20 gms Glean

sowed 75 kg Dollarbird wheat and 125 kg DAP / ha



60

Appendix 2. Springtail species found at the Cowra and Harden sites. Biogeographical origin is indicated by N (native), E (exotic) and ? (unknown). Functional group (FG) is defined in text. Immature stages appear in brackets, where they are deemed to belong to a different functional group to adults.

Cowra Harden Origin FG Cores Pitfalls Cores PitfallsBrachystomella platensis Najt and Massoud, 1974 N? B * * * * Ceratophysella gibbosa (Bagnall, 1940) E E * * * * Corynephoria reticulata Salmon, 1963 N C * Cryptopygus thermophilus (Axelson, 1900) E C * * * * Drepanura cinquilineata Womersley, 1934 N A * Drepanura coeruleopicta (Schott, 1917) N A * * Entomobrya multifasciata (Tullberg, 1871) E A (C) * * * * Entomobrya virgata Schott, 1917 N A (C) * * Entomobrya unostrigata Stach, 1930 E A (C) * * * * Fasciosminthurus virgulatus Skorikow, 1899 E B * * Folsomides parvulus Stach, 1922 N D * * * * Folsomina onychiurina Denis, 1931 N D * * * Hypogastrura manubrialis (Tullberg, 1869) E E * * Hypogastrura vernalis (Carl, 1901) E E * * * Isotoma sp. N C * * Isotomodes productus (Axelson, 1906) N D * * Jeannenotia stachi (Jeannenot, 1955) E A * * * * Katianna australis Womersley, 1932 N A * * * * Lepidocyrtus kuakea Christiansen and Bellinger, 1992 N? C * * * * Lepidosira nigrocephala (Womersley, 1936) N A * * Mesaphorura macrochaeta Rusek, 1976 E D * * * Megalothorax sp. ? D * * Proisotoma minuta (Tullberg, 1871) E C * Proisotoma filifera Denis, 1931 E C * Pseudosinella sp. ? D * * Sinella sp. ? D * * * * Sminthurinus elegans Fitch, 1863 E C * * * * Sminthurinus mime Borner, 1907 E C * * Sminthurinus sp.3 N C * * * * Sminthurinus sp.4 N C * * Sphaeridia sp. E C * * * Xenylla greensladeae Gama, 1974 N C * Xenylla sp. N C *

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Appendix 3. Species and morphospecies of mites fromCowra (FG = functional group).

Name Suborder FG Name Suborder FG

Acarus sp. ASTIGMATA W Indet. Oribatidae sp. ORIBATIDA X

Alicorhagidia sp. PROSTIGMATA Y Indet. Oripodidae sp. ORIBATIDA X

Alycosmesis sp. PROSTIGMATA W Indet. Tetranychidae sp. PROSTIGMATA T

Alycus sp. ASTIGMATA Y Javieroppia cervus ORIBATIDA Y

Antarctozetes sp. ORIBATIDA X Laelapidae sp. MESOSTIGMATA Y

Anystis sp. PROSTIGMATA Y Laelaps sp. "large leg II" sp. MESOSTIGMATA Y

Arctoseius cetratus MESOSTIGMATA Y Ledermuelleria sp. PROSTIGMATA T

Asca sp. MESOSTIGMATA Y Lepidoglyphus sp. ASTIGMATA W

Bakerdania "big" sp. PROSTIGMATA W Leptus sp. PROSTIGMATA Z

Bakerdania "elongate" sp. PROSTIGMATA W Lohmaniidae sp. ORIBATIDA W

Bakerdania "small" sp. PROSTIGMATA W Lorryia sp. PROSTIGMATA T

Bakerdania "squat" sp. PROSTIGMATA W Mesostigmata "elongate" sp. MESOSTIGMATA Y

Bdella sp. ASTIGMATA Y Microppia minus ORIBATIDA U

Bdellidae sp. PROSTIGMATA Y Multioppia sp. ORIBATIDA U

Benoinyssus sp. ASTIGMATA U Nanorchestes sp. PROSTIGMATA V

Brachychthonius sp. ORIBATIDA U Neocunaxoides sp. PROSTIGMATA Y

Brasilozetes sp. ORIBATIDA X Ologamasus sp. MESOSTIGMATA Y

Brassoppia sp. ORIBATIDA U Oppiella nova ORIBATIDA U

Brevipalpus sp. PROSTIGMATA T Parasitidae sp. MESOSTIGMATA Y

Calvolia sp. ASTIGMATA W Paratydeus sp. PROSTIGMATA Y

Coccorhagidia sp. PROSTIGMATA Y Pergamasus crassipes MESOSTIGMATA Y

Coccotydeolus sp. PROSTIGMATA V Prostigmata sp. PROSTIGMATA ?

Cryptognathus lateropunctatus PROSTIGMATA Y Protereunetes sp. PROSTIGMATA U

Cunaxidae sp. PROSTIGMATA Y Protogamasellus sp. MESOSTIGMATA Y

Cunaxoides sp. PROSTIGMATA Y Rhagidia sp. PROSTIGMATA Y

Discoppia sp. ORIBATIDA U Rhagidiidae sp. PROSTIGMATA Y

Dolichocybe sp. PROSTIGMATA W Scutacarus sp. PROSTIGMATA W

Endeostigmata sp. PROSTIGMATA ? Speleorchestes sp. PROSTIGMATA V

Epilohmannia pallida ORIBATIDA U Stigmaeidae sp. PROSTIGMATA Y

Eriophyidae sp. PROSTIGMATA T Stigmaeus sp. PROSTIGMATA Y

Erythracarus sp. PROSTIGMATA Y Suctobelba nondivisa ORIBATIDA U

Erythraeidae sp. PROSTIGMATA Y Suctobelbella sp. ORIBATIDA U

Eupodes sp. PROSTIGMATA U Tarsonemus sp. PROSTIGMATA W

Galumna sp. ORIBATIDA X Tectocepheus velatus ORIBATIDA U

Glycyphagidae sp. ASTIGMATA W Terpnacarus sp. PROSTIGMATA W

Graptoppia sp. ORIBATIDA U Tetranychus sp. PROSTIGMATA T

Halotydeus destructor PROSTIGMATA T Tydeidae sp. PROSTIGMATA V

Halotydeus sp. PROSTIGMATA T Tydeus sp. PROSTIGMATA V

Histiostoma sp. ASTIGMATA W Tyrophagus sp. ASTIGMATA X

Hypoaspis sp. MESOSTIGMATA Y Uropodidae sp. MESOSTIGMATA W

Indet. Ceratozetidae sp. ORIBATIDA X Veigaiidae sp. MESOSTIGMATA Y

Indet. hypopus ASTIGMATA W Vepracarus sp. ORIBATIDA U

Indet. Mesostigmata sp. MESOSTIGMATA Y Zygoribatula cf. longisporosa ORIBATIDA X

Indet. Oppiidae sp. ORIBATIDA U Zygoribatula sp. "gracile" ORIBATIDA X

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