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作者 Simandle, Eric T
書名 Population structure and conservation of two rare toad species (Bufo exsul and Bufo nelsoni) in the Great Basin, United States of America
國際標準書號 9780542756276
book jacket
說明 110 p
附註 Source: Dissertation Abstracts International, Volume: 67-06, Section: B, page: 2936
Adviser: C. Richard Tracy
Thesis (Ph.D.)--University of Nevada, Reno, 2006
In the Great Basin of the western United States, two rare species of anurans, black toads (Bufo exsul) and Amargosa toads ( Bufo nelsoni) may be particularly at risk for extinction. These toads live in isolated areas and have among the smallest geographic ranges of any North American anuran amphibians. This research integrates several measures of population dynamics to determine the status of these species and to examine the extent to which metapopulation structure exists within the black toad and the Amargosa toad. I take a rigorous approach, in that I evaluate the evidence for each of four characteristics of metapopulations, which are often mentioned in the context of metapopulation research but rarely thoroughly tested in any taxa. These four defining characteristics of metapopulation dynamics are: (1) that distinct breeding subpopulations exist, (2) that extinction and recolonization among subpopulations occur, (3) extinctions in subpopulations are primarily due to stochastic processes in otherwise suitable habitat, and (4) that there is limited dispersal among subpopulations. Both direct measures (mark-recapture, historical records, and observations) and indirect methods (i.e. genetic analyses) were used to evaluate the evidence for these four criteria. These analyses show that black toads exist as a metapopulation of at least three subpopulations. Amargosa toads exist as a metapopulation of at least five subpopulations. These findings have profound implications for our understanding of the species and the appropriate strategies for their conservation. For example, some important realizations in the metapopulation context include the expectations that some subpopulations may demonstrate a natural extinction-recolonization dynamic, that unoccupied but suitable habitat must be conserved as they represent areas that may be recolonized in the future, and that activities that increase patch isolation, or decrease patch size are detrimental to the persistence of the metapopulation. These results and conclusions should serve as a guide to science-based conservation and to the development of future research
School code: 0139
Host Item Dissertation Abstracts International 67-06B
主題 Biology, Ecology
Biology, Zoology
Environmental Sciences
Alt Author University of Nevada, Reno
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