Invasive Species “An alien species whose introduction does or is likely to cause economic or environmental harm or harm to human health…” “ „Alien species‟ means, with respect to a particular ecosystem, any species that is not native to that ecosystem.”
Disease Invasive species bring diseases not native to the ecosystem Detrimental to native species with no immunity Example: Asian chestnut blight fungus 180 million acres of forest destroyed Moth species living in chestnuts became extinct
Predators Reduce population sizes No evolved defenses Extinction Example: Brown Tree Snake Introduced to Guam through ship cargo Eliminated 10 of 11 species of bird species
Competition Invasivespecies are more efficient Native species are not as well adapted Example: North American gray squirrels Introduced to Great Britain and Italy Driving native red squirrels to extinction Forage for nuts more efficiently
Hybridization Members of two different species mate and successfully reproduce Invasive species is more abundant Genes “flood” the native species Forces extinction Genotype of native species phased out No selection for reproductive isolating mechanisms
Habitat Alteration Introduced species alter the ecological make up Cause harm to native species Example: Zebra Mussels
Zebra Mussels Brought to U.S. (Great Lakes) from Russia in ballast of ships Filter large amounts of water Reduce densities of planktonic organisms Settle in dense masses over expansive areas 30 freshwater mussel species threatened with extinction by competition
Deforestation The Tropical Rainforests Contain 50% of all 10 million species of plants, animals, and insects 50,000 disappear annually due to deforestation “Lungs of our planet”
Deforestation The Amazon Rainforest If destroyed, U.S. greenhouse gas emissions would increase 50 fold 90 indigenous tribes destroyed Loss of… Medicinal knowledge of plants, trees, and other species Great economic value if sustained
We suffer We pose a threat to future generations We have negative effect on them, but they have no effect on us Must maintain the earth for the future We are the greatest threats to ourselves
In Conclusion… Invasive species are a danger to many different ecosystems Humans are the most invasive species What must be done? Maintenance Education Reforms Protection of ecosystems
Sources"FARM: Farm Animal Rights Movement." The Cost of Disappearing Rainforests. Google Blogger, 14 Oct 2010. Web. 21 Nov. 2011.Hogan, C Michael. ”Causes of Extinction." Encyclopedia of Earth. 2010. Web. 21 Nov 2011. <http:// www.eoearth.org/article/Causes_of_extinction? topic=58074>.Hogan, C Michael. “Deforestation.” Encyclopedia of Earth. 2010. Web. 21 Nov 2011. http://www.eoearth.org/ article/Deforestation?topic=58071McGinley, Mark. "Invasive species". Encyclopedia of Earth. 2010. Web. 21 Nov 2011. http://www.eoearth.org/article/ Invasive_species?topic=49513.
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