3 Rarity

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Unformatted text preview: rsité d’Ottawa / University of Ottawa Rarity and extinction risk: Habitat specificity Species that have highly specialized habitat requirements are at higher risk because if this habitat is lost or degraded, there is no possibility of colonizing other habitats. Species 1 Species 2 Habitat B Habitat C Extinction risk Habitat A Species 1 Species 2 M3.20 BIO 3115 Université d’Ottawa / University of Ottawa M3 2009-2010.10 Rarity and extinction risk: Local population size Species with small populations are more likely to go extinct because at any given time, they are “closer” to the extinction threshold. Species 2 Species 1 Time Extinction risk Population size BIO 3115 Conservation Biology Species 1 Species 2 M3.21 BIO 3115 Université d’Ottawa / University of Ottawa Seven forms of rarity Geographic range Habitat specificity Large Broad Small Narrow Broad Narrow Locally abundant in several habitats but restricted geographically Uniformly sparse and geographically restricted in several habitats Locally abundant in a specific habitat but restricted geographically Uniformly sparse and geographically restricted in a specific habitat Local N: Somewhere large Common Locally abundant over a large range in a specific habitat Local N: Everywhere small Uniformly sparse over a large range and in several habitats Uniformly sparse in a specific habitat but over a large range M3.22 BIO 3115 Université d’Ottawa / University of Ottawa M3 2009-2010.11 BIO 3115 Conservation Biology M3.23 BIO 3115 Université d’Ottawa / University of Ottawa 2010-2011 Which species are more vulnerable to extinction extinction? Large species with a low reproductive potential Species with a high economic value Species at the top of long food chains (top predators) Species restricted to local, insular habitats Species that have a high degree of specialization for resources that are relatively rare Some migratory species, which are vulnerable to habitat disruption in both breeding and wintering areas. M3.24 BIO 3115 Université d’Ottawa / University of Ottawa M3 2009-2010.12 BIO 3115 Conservation Bi...
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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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