Managing Ludwigia peruviana (L.) Hara & Ludwigia ...
Transcript of Managing Ludwigia peruviana (L.) Hara & Ludwigia ...
9th Ecology and Management of Alien Plant Invasions Conference, Perth, Australia 17-21 September 2007
Dr. Nimal ChandrasenaDr. Nimal ChandrasenaGHD Pty LtdGHD Pty Ltd
Managing Managing LLudwigiaudwigia peruvianaperuviana (L.) H(L.) Haraara & & LLudwigiaudwigia longifolialongifolia (DC) H(DC) Haraara infestations in NSW: infestations in NSW:
Progress and ProspectsProgress and Prospects
id2905171 pdfMachine by Broadgun Software - a great PDF writer! - a great PDF creator! - http://www.pdfmachine.com http://www.broadgun.com
OUTLINEOUTLINE
1.1. The Invaders in Sydney and NSW, Australia The Invaders in Sydney and NSW, Australia
2.2. Magnitude of infestationsMagnitude of infestations
3.3. Focus on managementFocus on management-- Case studies Case studies
4.4. Spread across NSWSpread across NSW
5.5. Conclusions Conclusions �� What we have learntWhat we have learnt
9th Ecology and Management of Alien Plant Invasions Conference, Perth, Australia 17-21 September 2007
Sydney BasinSydney Basin
Hawksberry-Nepean River
Botany Wetland
Sydney Airport
Introducing the InvadersIntroducing the Invaders
Ludwigia peruvianaLudwigia peruviana (L.) Hara (Primrose Willow) (= (L.) Hara (Primrose Willow) (= JussiaeaJussiaea
peruviana, J. peruviana, J. grandifloragrandiflora, J. , J. suffruticosasuffruticosa))
Ludwigia longifoliaLudwigia longifolia (DC.) Hara ((DC.) Hara (LongLong--leaf Willow Primrose)leaf Willow Primrose)
ONAGRACEAEONAGRACEAE
Native areaNative area-- Central AmericaCentral America
PanPan--tropical, 0tropical, 0--1450 m altitude (Indonesia, Sri Lanka)1450 m altitude (Indonesia, Sri Lanka)
In the Sydney basinIn the Sydney basin-- (30(3000 South latitude)South latitude)
L. peruvianaL. peruviana-- in 1971 (escape from Botanic Gardens)in 1971 (escape from Botanic Gardens)
L. longifoliaL. longifolia-- In 1991 (escape from Nurseries ?)In 1991 (escape from Nurseries ?)
9th Ecology and Management of Alien Plant Invasions Conference, Perth, Australia 17-21 September 2007
� Water supply, Sydney 1850-1866
� 59 Ha wetlands, 11 ponds + land
� 4 Km, eastern suburbs, open to the Botany bay
� Flood-mitigation system
� Largest freshwater lakes
� Water supply, Sydney 1850-1866
� 59 Ha wetlands, 11 ponds + land
� 4 Km, eastern suburbs, open to the Botany bay
� Flood-mitigation system
� Largest freshwater lakes
Botany WetlandsBotany Wetlands-- SydneySydney
9th Ecology and Management of Alien Plant Invasions Conference, Perth, Australia 17-21 September 2007
Botany WetlandsBotany Wetlands-- SydneySydney
o Highly valued (native vegetation, wildlife habitats, aesthetic)
o Degraded by aquatic weeds (Ludwigia peruviana, Alligator Weed, Salvinia, Water Hyacinth) and Invasive trees (Willows, Coral trees)
1996
9th Ecology and Management of Alien Plant Invasions Conference, Perth, Australia 17-21 September 2007
� Pond 3 (75% cover of L.p)
� Invasive Willows, Coral trees
� Pond 3 (75% cover of L.p)
� Invasive Willows, Coral trees
P 3
P 5
Botany WetlandsBotany Wetlands-- Pond 3Pond 3
9th Ecology and Management of Alien Plant Invasions Conference, Perth, Australia 17-21 September 2007
Ludwigia peruvianaLudwigia peruviana in Sydneyin Sydney
2.5 m
9th Ecology and Management of Alien Plant Invasions Conference, Perth, Australia 17-21 September 2007
� Pond 1 (90% cover of L.p)
� Invasive Willows, Coral trees
� Pond 1 (90% cover of L.p)
� Invasive Willows, Coral trees
Botany WetlandsBotany Wetlands-- Pond 1Pond 1
P 1
P 2
9th Ecology and Management of Alien Plant Invasions Conference, Perth, Australia 17-21 September 2007
� Pond 1A (90% cover of L.p)
� Invasive Willows
� Pond 1A (90% cover of L.p)
� Invasive Willows
Botany WetlandsBotany Wetlands-- Pond 1APond 1A
Willow groveWillow grove
9th Ecology and Management of Alien Plant Invasions Conference, Perth, Australia 17-21 September 2007
Ludwigia peruvianaLudwigia peruviana-- potential distributionpotential distribution
9th Ecology and Management of Alien Plant Invasions Conference, Perth, Australia 17-21 September 2007
Integrated Weed ManagementIntegrated Weed Management
9th Ecology and Management of Alien Plant Invasions Conference, Perth, Australia 17-21 September 2007
Integrated Weed ManagementIntegrated Weed Management
RevegetationRevegetation--�� Assisted regenerationAssisted regeneration�� Purposeful planting of native speciesPurposeful planting of native species�� TansplantingTansplanting macrophytesmacrophytes�� Bush regenerationBush regeneration�� Habitat creationHabitat creation-- logs, snagslogs, snags
9th Ecology and Management of Alien Plant Invasions Conference, Perth, Australia 17-21 September 2007
Before (up to 1996) Before (up to 1996) After (2006)After (2006)
� Serious noxious weeds
� Poor water quality, murky water
� Stagnant water due to choking
� Toxic algal blooms annually,
� Feral fish (European Carp)
� Poor diversity of native plants
� Less noxious weeds, invasive trees
� better water quality, water clarity (>3.0 m)
� Vastly improved flow
� No algal blooms, reduced feral fish
� Native plants- greater diversity
Botany Wetlands, SydneyBotany Wetlands, Sydney
9th Ecology and Management of Alien Plant Invasions Conference, Perth, Australia 17-21 September 2007
Pond 1A
Before (up to 1996) Before (up to 1996)
Botany Wetlands, Botany Wetlands, SydneySydney
After (2006) After (2006)
9th Ecology and Management of Alien Plant Invasions Conference, Perth, Australia 17-21 September 2007
� 1 frog species; 99 bird species (1991)
� 6 frog species; 164 bird species (2004)
Botany Wetlands, SydneyBotany Wetlands, Sydney
9th Ecology and Management of Alien Plant Invasions Conference, Perth, Australia 17-21 September 2007
Vegetation Changes- Botany Wetlands
0
10
20
30
40
50
60
70
80
1996 1998 2000 2002 2005
% A
rea
Ludw igia
Undesirable Vegetation
Native Vegetation
Open Water� L. peruviana- negligible
� Native vegetation (Typha orientalis, three Baumea sp., Phragmites australis, Juncussp., Cyperus sp., Schoenoplectus sp., Elaeocharissp. + many others)
Botany WetlandsBotany Wetlands-- Annual costs of implementing IWM and Annual costs of implementing IWM and monitoring Ecological Healthmonitoring Ecological Health
Annual Monitoring- WQ, Macroinvertebrates, Frogs, Reptiles, AusrivasSIGNAL Index, Vegetation
Birds- once in 5 years
Annual Costs of Implementing IWM- Botany Wetlands
0
50
100
150
200
250
300
350
400
1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006
Au
s $
'000
Total costs
IWM- on ground costs
Management costs
9th Ecology and Management of Alien Plant Invasions Conference, Perth, Australia 17-21 September 2007
Monitoring Review
New POM
Ludwigia longifoliaLudwigia longifolia-- north of Sydney (Newcastle)north of Sydney (Newcastle)
� Location of Mambo Wetlands (175 ha), Salamander Bay, Port Stephens,
� Largest infestations of L. longifolia- first found
� Note closeness to the port city Newcastle, north of Sydney.
� Other infestations, thus far are small and sporadic in occurrence.
9th Ecology and Management of Alien Plant Invasions Conference, Perth, Australia 17-21 September 2007
Ludwigia longifoliaLudwigia longifolia
L. l found in Botany Wetlands in 1991, 2002, L. l found in Botany Wetlands in 1991, 2002, 2005; Just upstream of drain is a nursery2005; Just upstream of drain is a nursery
Controlled with herbicides + manual removalControlled with herbicides + manual removal
Persistent seedsPersistent seeds
9th Ecology and Management of Alien Plant Invasions Conference, Perth, Australia 17-21 September 2007
L. peruvianaL. peruviana has has spread widely over spread widely over the past 12 years, the past 12 years, despite despite implementation of implementation of Regional WMPRegional WMP
L. longifolia has L. longifolia has appeared in a few appeared in a few locations, sporadic locations, sporadic patchespatches
Lessons learntLessons learnt-- Focus of managementFocus of managementUnderstand biological attributes of the invader, which make themUnderstand biological attributes of the invader, which make theminvasives (seed production, vegetative reproduction etc.); invasives (seed production, vegetative reproduction etc.); Understand why such species have invadedUnderstand why such species have invaded
Coordinated management captured by one NSW DPI Regional Coordinated management captured by one NSW DPI Regional WMP for both species; WMP for both species; Plan for the entire catchment (watershed) Plan for the entire catchment (watershed) and regionand region
Eradication vs containment ? Relatively easy to treat (if there Eradication vs containment ? Relatively easy to treat (if there is is Commitment)Commitment)
Integrated Weed Management (Early detection, prevention of Integrated Weed Management (Early detection, prevention of spread, herbicides, mechanical removal, burning, cultural controspread, herbicides, mechanical removal, burning, cultural control) l)
no biono bio--control agent yet; not an option in early 1990s because of control agent yet; not an option in early 1990s because of limited resources and need for more urgent actionlimited resources and need for more urgent action
9th Ecology and Management of Alien Plant Invasions Conference, Perth, Australia 17-21 September 2007
Eradication strategy is workable, so long has the invader has noEradication strategy is workable, so long has the invader has not t spread too muchspread too much
Improved reporting and sharing of informationImproved reporting and sharing of information
Improved Contract specs & contract management; Improved Contract specs & contract management; Training (weed Training (weed contractors)contractors)
Improved project implementation can bring about successImproved project implementation can bring about success--
oo Eradication should be a goal with these two speciesEradication should be a goal with these two species
oo Learning from successful projects Learning from successful projects
oo Set performance targets (i.e. reduce local infestations by 50% iSet performance targets (i.e. reduce local infestations by 50% in n next 12 monthsnext 12 months��.).)
oo Monitor costs, achievement, reportMonitor costs, achievement, report
Lessons learntLessons learnt-- Focus on managementFocus on management
9th Ecology and Management of Alien Plant Invasions Conference, Perth, Australia 17-21 September 2007
ConclusionsConclusions
Some invasive species are moving with human disturbancesSome invasive species are moving with human disturbances
These species are only doing what they are meant to doThese species are only doing what they are meant to do-- i.e. exploit i.e. exploit vacant vacant ��nichesniches�� created by disturbances, maintain fecundity (rcreated by disturbances, maintain fecundity (r--strategists)strategists)
Spread caused by and sustained by Spread caused by and sustained by urbanisationurbanisation impactsimpacts
Aggressive Aggressive ��maintenance controlmaintenance control�� until comprehensive until comprehensive WMPsWMPs for for areas, regions are producedareas, regions are produced
Stronger insistence on interStronger insistence on inter--agency cooperation & information agency cooperation & information sharingsharing
Keep a watch on other Ludwigias (Keep a watch on other Ludwigias (L. L. hyssopifoliahyssopifolia, L. , L. decurrensdecurrens, L. , L. octovalvisoctovalvis) )
Immigrants to Invaders !!Immigrants to Invaders !!
9th Ecology and Management of Alien Plant Invasions Conference, Perth, Australia 17-21 September 2007
Thank youThank you