Smart grassland systems - ucd.ie relationship between sward diversity... · G ra s &L egum 7 0:3 H...
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Biodiversity for production Smart grass This research has been funded by the Research Stimulus Fund, Department of Agriculture, Food and the Marine: Grant No. 11/S/147 Smart grassland systems: The relationship between sward diversity and invertebrate communities in experimental grasslands www.smartgrass.ie Samples were preserved in 70% ethanol prior to sorting and identification. Parasitic Hymenoptera and Coleoptera individuals were counted from eight suction samples taken during August 2014. These eight samples represent a subset of the SmartGrass plots; they each receive an input of 90 kg N ha -1 yr -1 , and range from one to three functional groups, which are present in varying ratios (there is a minimum of 40% grass in all plots for agronomic reasons). Statistical analysis was performed using MINITAB. Multiple regression analysis was used to investigate if there was a relationship between the abundance of parasitic Hymenoptera and Coleoptera and the presence/abundance of plant functional groups. Results/Discussion Parasitic Hymenoptera and Coleoptera were most abundant in plots with a mixture of legume, herb and grass (Figure 1). These results indicate that multi-species swards support a greater abundance of parasitic Hymenoptera and Coleoptera. A comprehensive study has shown that the abundance of parasitic Hymenoptera can be used effectively to predict overall arthropod taxon richness in agro-ecosystems (Anderson et al ., 2011). Multi-species swards have huge potential for transforming agricultural grassland ecosystems in Ireland from those supporting small, non-diverse populations of invertebrates to those supporting a more diverse community, which may lead to enhanced ecosystem functioning and improved provision of ecosystem services. References Anderson, A. et al. (2011) The potential of parasitoid Hymenoptera as bioindicators of arthropod diversity in agricultural grasslands. Journal of Applied Ecology, 48, 382-390. Cardinale, B.J. et al. (2007) Impacts of plant diversity on biomass production increase through time because of species complementarity. Proceedings of the National Academy of Sciences of the United States of America, 104, 18123-18128. Cornell, J.A. (2002) Experiments with Mixtures: Designs, Models, and the Analysis of Mixture Data, 3rd edition. Wiley, Chichester. Introduction Terrestrial arthropods represent a significant component of functional biodiversity within agricultural ecosystems. They contribute to the overall sustainability of these systems through their involvement in a range of ecosystem processes, i.e. nutrient cycling and pest biocontrol. Ecological theory states that multi-species plant communities should support a greater diversity of invertebrates relative to a monoculture crop; this is due to the wider range of potential niches they provide (Cardinale et al ., 2007). This study focused on populations of parasitic Hymenoptera and Coleoptera. It was hypothesised that these invertebrate groups would be more abundant in the multi-species swards compared to the monocultures due to the presence of more plant functional groups. Materials & methods The experiment, established in the summer of 2013, uses a constrained simplex-centroid design (Cornell, 2002) with nine plant species representing three functional groups (grasses, legumes and herbs). Grazing was simulated by cutting to a height of 4cm eight times during the growing season. Invertebrates were sampled using a Vortis suction sampler (Burkard Manufacturing Ltd.) in June and August 2014, two weeks after the previous harvest, i.e. at the midpoint of growth. Samples consisted of 10 randomly positioned suction samples each of 10 sec. duration (covering a total area of 2 m 2 per plot). Heather Cuddy * , Rochelle Fritch & Helen Sheridan UCD School of Agriculture & Food Science, *Corresponding author: [email protected] R Figure 1. Contour plots from multiple regression analysis, interaction effects of legumes & herbs for: (a) parasitic Hymenoptera ( p=0.08, r 2 = 94.4%) (b) Coleoptera (p=0.02, r 2 = 97.76%), n=8. Abundance of parasitic Hymenoptera > – – – – – – < 20 20 25 25 30 30 35 35 40 40 45 45 50 50 Grass 100:0:0 Grass & Legume 70:30:0 Grass & Herb 70:0:30 Ratios are grass : legume : herb Abundance of Coleoptera Grass 100:0:0 Grass & Legume 70:30:0 Grass & Herb 70:0:30 Legume & Herb 40:30:30 Legume 40:60:0 Herb 40:0:60 > – – – – < 20 20 24 24 28 28 32 32 36 36 Legume & Herb 40:30:30 Legume 40:60:0 Herb 40:0:60 (a) (b)
Transcript of Smart grassland systems - ucd.ie relationship between sward diversity... · G ra s &L egum 7 0:3 H...
Biodiversity for productionSmart grass
This research has been funded by the Research Stimulus Fund, Department of Agriculture, Food and
the Marine: Grant No. 11/S/147
Smart grassland systems: The relationship between sward diversity and invertebrate
communities in experimental grasslands
www.smartgrass.ie
Samples were preserved in 70% ethanol prior to sorting and identi�cation. Parasitic
Hymenoptera and Coleoptera individuals were counted from eight suction samples taken
during August 2014. These eight samples represent a subset of the SmartGrass plots; they each
receive an input of 90 kg N ha-1 yr-1, and range from one to three functional groups, which are
present in varying ratios (there is a minimum of 40% grass in all plots for agronomic reasons).
Statistical analysis was performed using MINITAB. Multiple regression analysis was used to
investigate if there was a relationship between the abundance of parasitic Hymenoptera and
Coleoptera and the presence/abundance of plant functional groups.
Results/DiscussionParasitic Hymenoptera and Coleoptera were most abundant in plots with a mixture of legume, herb and grass (Figure 1). These results indicate that multi-species swards support a greater abundance of parasitic Hymenoptera and Coleoptera. A comprehensive study has shown that the abundance of parasitic Hymenoptera can be used e�ectively to predict overall arthropod taxon richness in agro-ecosystems (Anderson et al., 2011). Multi-species swards have huge potential for transforming agricultural grassland ecosystems in Ireland from those supporting small, non-diverse populations of invertebrates to those supporting a more diverse community, which may lead to enhanced ecosystem functioning and improved provision of ecosystem services.
ReferencesAnderson, A. et al. (2011) The potential of parasitoid Hymenoptera as bioindicators of arthropod diversity in agricultural grasslands. Journal of Applied Ecology, 48, 382-390.
Cardinale, B.J. et al. (2007) Impacts of plant diversity on biomass production increase through time because of species complementarity. Proceedings of the National Academy of Sciences of the United States of America, 104, 18123-18128.
Cornell, J.A. (2002) Experiments with Mixtures: Designs, Models, and the Analysis of Mixture Data, 3rd edition. Wiley, Chichester.
IntroductionTerrestrial arthropods represent a signi�cant component of functional biodiversity within agricultural ecosystems. They contribute to the overall sustainability of these systems through their involvement in a range of ecosystem processes, i.e. nutrient cycling and pest biocontrol. Ecological theory states that multi-species plant communities should support a greater diversity of invertebrates relative to a monoculture crop; this is due to the wider range of potential niches they provide (Cardinale et al., 2007). This study focused on populations of parasitic Hymenoptera and Coleoptera. It was hypothesised that these invertebrate groups would be more abundant in the multi-species swards compared to the monocultures due to the presence of more plant functional groups.
Materials & methodsThe experiment, established in the summer of 2013, uses a constrained simplex-centroid design (Cornell, 2002) with nine plant species representing three functional groups (grasses, legumes and herbs). Grazing was simulated by cutting to a height of 4cm eight times during the growing season.
Invertebrates were sampled using a Vortis suction sampler (Burkard Manufacturing Ltd.) in June and August 2014, two weeks after the previous harvest, i.e. at the midpoint of growth. Samples consisted of 10 randomly positioned suction samples each of 10 sec. duration (covering a total area of 2 m2
per plot).
Heather Cuddy
*, Rochelle Fritch & Helen Sheridan
UCD School of Agriculture & Food Science,
*Corresponding author: [email protected]
Grass 100:0:0
Legume40:60:0
Herb40:0:60
Grass & Herb70:0:30Grass & Legume
70:30:0
Centroid mixtures60:20:20
Legume & Herb40:30:30
Agronomic mixtures55:35:10
Ratios aregrass : legume : herb
R
Abundance of Parasitoid wasps
> – – – – – – < 20
20 2525 3030 3535 4040 4545 50
50
Grass 100:0:0
Grass & Legume70:30:0
Grass & Herb70:0:30
Legume & Herb40:30:30
Legume40:60:0
Herb40:0:60
Ratios aregrass : legume : herb
Abundance of Parasitoid wasps
> – – – – – – < 20
20 2525 3030 3535 4040 4545 50
50
Grass 100:0:0
Grass & Legume70:30:0
Grass & Herb70:0:30
Legume & Herb40:30:30
Legume40:60:0
Herb40:0:60
Ratios aregrass : legume : herb
Figure 1. Contour plots from multiple regression analysis, interaction e�ects of legumes & herbs for: (a) parasitic Hymenoptera ( p=0.08, r 2 = 94.4%) (b) Coleoptera (p=0.02, r 2 = 97.76%), n=8.
Abundance of ColeopteraGrass
100:0:0
Grass & Legume70:30:0
Grass & Herb70:0:30
Legume & Herb40:30:30
Legume40:60:0
Herb40:0:60
> – – – – < 20
20 2424 2828 3232 36
36
Abundance of parasitoid wasps
Abundance of Parasitoid wasps
> – – – – – – < 20
20 2525 3030 3535 4040 4545 50
50
Grass 100:0:0
Grass & Legume70:30:0
Grass & Herb70:0:30
Ratios aregrass : legume : herb
Abundance of ColeopteraGrass
100:0:0
Grass & Legume70:30:0
Grass & Herb70:0:30
Legume & Herb40:30:30
Legume40:60:0
Herb40:0:60
> – – – – < 20
20 2424 2828 3232 36
36
Legume & Herb40:30:30
Legume40:60:0
Herb40:0:60
Abundance of Parasitoid wasps
> – – – – – – < 20
20 2525 3030 3535 4040 4545 50
50
Grass 100:0:0
Grass & Legume70:30:0
Grass & Herb70:0:30
Ratios aregrass : legume : herb
Abundance of ColeopteraGrass
100:0:0
Grass & Legume70:30:0
Grass & Herb70:0:30
Legume & Herb40:30:30
Legume40:60:0
Herb40:0:60
> – – – – < 20
20 2424 2828 3232 36
36
Legume & Herb40:30:30
Legume40:60:0
Herb40:0:60
Abundance of parasitic Hymenoptera
> – – – – – – < 20
20 2525 3030 3535 4040 4545 50
50
Grass 100:0:0
Grass & Legume70:30:0
Grass & Herb70:0:30
Ratios aregrass : legume : herb
Abundance of ColeopteraGrass
100:0:0
Grass & Legume70:30:0
Grass & Herb70:0:30
Legume & Herb40:30:30
Legume40:60:0
Herb40:0:60
> – – – – < 20
20 2424 2828 3232 36
36
Legume & Herb40:30:30
Legume40:60:0
Herb40:0:60
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0.6
0.8
1.0
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(a) (b)
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