Species threatened with extinction are the focus of mounting conservation concerns throughout the world. Thirty-seven years after passage of the U.S. Endangered Species Act in 1973, we conclude that the Act's underlying assumption-that once the recovery goals for a species are met it will no longer require continuing management-is false. Even when management actions succeed in achieving biological recovery goals, maintenance of viable populations of many species will require continuing, species-specific intervention. Such species are "conservation reliant." To assess the scope of this problem, we reviewed all recovery plans for species listed as endangered or threatened under the Act. Our analysis indicates that 84% of the species listed under the Act are conservation reliant. These species will require continuing, long-term management investments. If these listed species are representative of the larger number of species thought to be imperiled in the United States and elsewhere, the challenge facing conservation managers will be logistically, economically, and politically overwhelming. Conservation policies will need to be adapted to include ways of prioritizing actions, implementing innovative management approaches, and involving a broader spectrum of society.
Survival and cause-specific mortality estimates are needed to develop effective conservation strategies for the endangered ocelot (Leopardus pardalis) in the United States. We radiomonitored 80 ocelots (36 F, 44 M) from 1983 to 2002 and analyzed survival and cause-specific mortality rates. Pooled estimates of annual survival rates differed between resident (Ŝ = 0.87) and transient (Ŝ = 0.57) ocelots (P = 0.02); therefore, survival and cause-specific mortality analyses were partitioned for resident and transient ocelots. Sex-specific annual survival was similar between resident ocelots (M = 0.92, F = 0.83, P = 0.16) and transient ocelots (M = 0.53, F = 0.63, P = 0.75). Most mortalities were from human (e.g., ocelot-vehicle collisions; M = 45%) and natural (e.g., animal attack, disease; M = 35%) sources. Transient ocelots had higher natural mortality rates (disease, intraspecific mortality; M = 0.26) than resident ocelots (M = 0.04, P = 0.03). Other sources of mortality did not differ (P ≥ 0.10) between resident or transient ocelots or male and female resident or transient ocelots (P ≥ 0.08). Human population expansion within the Lower Rio Grande Valley of southern Texas, USA, will increase transportation-related problems and decrease the quantity of ocelot habitat, leading to increased ocelot-vehicle collisions and possibly cause more transient behavior, thus significantly lowering ocelot survival. Research and development of ocelot road underpasses should be conducted to mitigate ocelot-vehicle collisions.
JOURNAL OF WILDLIFE MANAGEMENT 69(1):255-263; 2005
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