36 bio 3115 universit dottawa university of ottawa

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Unformatted text preview: Conservation Biology Urchin density (Shemya) Urchin density (Amchitka) Kelp coverage (Shemya) Kelp coverage (Amchitka) 150 100 50 Amchitka Sea urchin density (no./.25 m2 ) Kelp coverage (%) Dramatic reductions in Sea Otter populations at Shemya resulted in increased sea urchin densities, especially in shallow water, and dramatically reduced kelp beds, which in turn resulted in severely reduced mollusc populations due to habitat loss. c. 1945 c. 1970 200 Sheyma 120 100 80 60 40 20 0 0 5 10 15 20 25 Depth (m) M7.37 BIO 3115 Université d’Ottawa / University of Ottawa 2012 Exploitation and cumulative risks While a certain level of exploitation may be sustainable in the absence of other risk factors, if such other factors exists, extinction risk may increase dramatically beyond the summed (additive) effects of each factor. Extinction risk Sea otter density (no./10 km2) The effects of sea otter exploitation Exploitation Habitat loss Both M7.38 BIO 3115 Université d’Ottawa / University of Ottawa 2012 M7.19 BIO 3115 Conservation Biology...
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This document was uploaded on 03/11/2014 for the course BIO 3115 at University of Ottawa.

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