Available at http://planet.uwc.ac.za/nisl/Eco_people/Presentations/
The Biology and Dynamics of The Biology and Dynamics of Biological invasionsBiological invasions
Megan Van Der Bank2401402
Department of Biodiversity and Conservation Biology, University
of the Western Cape
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IndexIndex
Introduction Invasive Argentinean ants in the Fynbos Biome Weeds in Australian rangelands The Black striped mussel in Australia Acacia mearnsii in South Africa The Cane Toad (Bufo marinus) in Australia The invasive Red deer (Cervus elaphus)
The Chinese Mitten Crab (Eriocheir sinensis) Invasive Red mangroves and pickleweed in Hawaiian wetlands The local and global effects of invasive species on biodiversity References
Presently, alien species are one of the biggest threats to biodiversity, only second to habitat destruction
Globalization has increase mobility of biota
Intentional introductions (McNeely. 2001)
Accidental introduction (Chapin et al. 2000)
Alien species become naturalized
Outcompete native species for natural resources (Chapin et al. 2000) and prey on indigenous species
These invasive species lack natural enemies, which gives them a competitive edge
Many become pests
IntroductionIntroduction
Invasive Argentinean ants in the Fynbos BiomeInvasive Argentinean ants in the Fynbos Biome
Invasive Iridomyrmex humilis displace native ants Slower to discover seeds of myrmecochorous Mimetes
cucullatus; seeds are moved shorter distances; fail to store seeds below soil
Exposure to competitors, predators and fire Affects seedling growth which competes with parent plant
(Bond and Slingsby. 1984)
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Weeds in Australian rangelandsWeeds in Australian rangelands
Australian rangelands constitute 70 % of the Australian continent Rate of naturalization is 10 species per year Weeds are able to reach high densities and biomass-dominating
the stratum Weeds sequester resources otherwise available to native plant
species Landscape dysfunction- ramifications for food web Effect on specialist herbivores; decomposers Alter fire regimes Native plant species richness decease; native animal species may
respond positively or negatively (Grice. 2004)
Native to tropical and sub-tropical waters of the Western Atlantic (Columbia to the Gulf of Mexico) [1]
Detected in Darwin Harbour (1999) in Australia’s Northern Territory
Introduction via vessel hull fouling; fouling of aquaculture; ballast
Bivalves able to form dense monospecific mats
Reduction in biodiversity, fouling of wharves, seawater systems and marine farms [1]
Treatment with copper sulphate and sodium hypochlorite [4]
Total cost of $ 2.2 million per annum (excluding personnel costs) [1]
The Black striped mussel in AustraliaThe Black striped mussel in Australia
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Native to Australia and was introduced into South Africa about 150 years ago as a source of bark products [2]
Invasive in South Africa and other countries such as China, Japan, New Zealand, France, United States [3]
S. mearnsii able to produce copious amounts of long lived seeds [2][3]
Forms monospecific crowns which shades other vegetation [2]
Competes with grazing grasses resulting in decreased grass cover
Taps into South Africa’s already dwindling water supply (577 million cubic meters annually) [2]
Increased fuel loads affects fire intensity (Ehrenfeld. 2006)
Nitrogen enrichment (due to nitrogen fixation) makes habitat unsuitable for growth of indigenous species, and more susceptible to invasion by other exotics (Ehrenfeld. 2006)
Infested areas shows decreased species richness of birds and ground plant cover [2]
Acacia mearnsiiAcacia mearnsii in South Africa in South Africa
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Indigenous to South America, Central America, Mexico, Southern United States
Deliberately introduced into Australia as a biological control agent to prevent French’s Cane Beetle from destroying sugar cane in Northern Queensland [4]
Very fecund (females produce 8000-35 000 eggs, usually twice a year [4]
Adaptable: able to loose 50 % of its body water, tolerate salinities up to 15 % [4]
Competes with native amphibians for breeding ground and food
Toxic at all life stages and causes death of indigenous animals
Current research for control: biological control from a native amphibian virus (gene manipulation) [4]
The Cane Toad (The Cane Toad (Bufo marinusBufo marinus) in Australia) in Australia
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The invasive Red deer (The invasive Red deer (Cervus elaphusCervus elaphus))
Native to parts of Europe and was introduced into Australia, New Zealand, North America and South America [5]
Invades natural and planted forests, rangelands, grasslands, shrublands, tundra
Prevents regeneration of preferred plant species (may cause canopy collapse in woodland and forest settings) [5]
Change structure and composition of native ecosystems Competes with native deer species such as (Hippocamelus
bisulcus) in Chile [5]
Loss of heather cover in the highlands of Scotland
(Clutton-Brock et al. 2004)
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The Chinese Mitten Crab (The Chinese Mitten Crab (Eriocheir sinensisEriocheir sinensis)) Recognized as one of the world’s top 100 invaders by the ISSG
(Invasive species specialist group) [7]
Native to the coastal rivers and estuaries of the Yellow Sea (West China, Korea) [7][8]
Has spread widely in the US (Great Lakes, California, Pacific Northwest, Louisiana, mouth of the Mississippi River) and become established in Northern Europe
Introduction via live seafood trade, ballast, ship hull fouling Success of E. sinensis is due to tolerance to a varying hydrological
conditions and high female fecundity [7]
Pest: consume young rice shoots, commercial fishing, human health concern [6]
Affects landscape and biodiversity in infested areas : degrade estuarine and freshwater food webs; compete directly with indigenous invertebrates; successive burrowing causes landscape instability [6]
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Invasive Red mangroves and pickleweed in Hawaiian Invasive Red mangroves and pickleweed in Hawaiian wetlandswetlands
Alien red mangroves (Rhizophora mangle) and pickleweed (Batis maritima) are major invasive plants in Hawaiian wetlands
Nu’upia fish pond complex home to 10 % of Hawaii’s endangered black-necked stilts (Himantopus mexicanus knudseni)
Pickleweed introduced from South America in 1859 Excludes shorebirds and waterbirds from foraging and nesting on
mudflats (Rauzon and Drigot. 2001) Mangroves introduced from Florida in 1902 to mitigate erosion Decrease water circulation, increases algal production, anoxia,
increases temperature, salinity and acidity of water Stilts more vulnerable to predation by egrets and herons Control measures include: Amphibious Assault Vehicles (pickleweed
control); manual cutting down of trees; possible biological control (Rauzon and Drigot. 2001)
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The local and global effects of invasive species on The local and global effects of invasive species on biodiversitybiodiversity
As a biodiversity issue, it is not always possible to say that invasive species are inherently bad (McNeely. 2001)
Globalization causes homogenization Homogenization not synonymous to low diversity at a local scale Dramatic increase in species numbers at a local level, is at expense of
native species Loss of rate native species, leads to global species and genetic
diversity loss (McNeely. 2001) Consensus dependant partly on scale (McNeely. 2001)
References Davis M (2003) Biotic Globalization: Does Competition from introduced
species Threaten Biodiversity? BioScience 53: 481-488 Bond W, Slingsby P (1984) Collapse of an ant-plant mutualism: The Argentine
ant (Iridomyrmex humilis) and myrmecochorous Proteaceae. Ecology 65:1031-1037
Chapin F, Zavaleta E, Eviner V, Naylor R, Vitousek P, Reynolds H, Hooper D, Lavorel S, Sala O, Hobbie S, Mack M, Diaz S (2000) Consequences of changing biodiversity. Nature 405: 234-242
Clutton- Brock T, Coulson T,Milner J (2004) Red deer stocks in the Highlands of Scotland. Nature 429:261
Ehrenfeld J (2006) A potential novel source of information of screening and monitoring the impact of exotic plants on ecosystems. Biological Invasions 8: 1511-1521
Grice A (2004) Weeds and the monitoring of biodiversity in Australian rangelands. Austral Ecology 29: 51-58
McNeely J (2001) Invasive species: a costly catastrophe for native biodiversity. Land Use and Water Resources Research 1: 1-19
Rauzon M, Drigot D (2001) Turning the tide: the eradication of invasive species. IUCN SSC Invasive Species Specialist Group, Cambridge p240-248
12. http://www.biodiv.org/doc/case-studies/ais/cs-ais-au-black-mussel-en.pdf 13. http://www.issg.org/database/species/impact_info.asp?si=51&fr=1&sts= 14. http://www.hear.org/species/acacia_mearnsii/ 15. http://www.aph.gov.au/senate/committee/ecita_ctte/invasive_species/report/c04.
pdf 16. http://www.fao.org/docrep/008/j6854e/J6854E12.htm 17. http://www.wsg.washington.edu/outreach/mas/nis/leastwanted.pdf
18. http://cswgcin.nbii.gov/portal/server.pt?open=512&objID=798&&PageID=2259&mode=2&in_hi_userid=2&cached=true
19. http://cars.er.usgs.gov/posters/Nonindigenous/Nonindigenous_Crustaceans/nonindigenous_crustaceans.html
20. http://en.wikipedia.org/wiki/Invasion_biology_terminology