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Full-Text Articles in Aquaculture and Fisheries
Wetland Hydrodynamics And Long-Term Use Of Spring Migration Areas By Lesser Scaup In Eastern South Dakota, Sharon N. Kahara, Steven R. Chipps
Wetland Hydrodynamics And Long-Term Use Of Spring Migration Areas By Lesser Scaup In Eastern South Dakota, Sharon N. Kahara, Steven R. Chipps
Great Plains Research: A Journal of Natural and Social Sciences
Lesser scaup (Aythya affinis [Eyton]) populations remain below their long-term average despite improved habitat conditions along spring migration routes and at breeding grounds. Scaup are typically associated with large, semipermanent wetlands and exhibit regional preferences along migration routes. Identifying consistently used habitats for conservation and restoration is complicated by irregular wetland availability due to the dynamic climate. We modeled long-term wetland use by lesser scaup in eastern South Dakota based on surveys conducted during below-average (1987-1989) and above-average (1993-2002) water condition years. Wetland permanence, longitude, and physiographic region were all significant determinants of use (P < 0.01). Long-term use was best described by a quadratic equation including wetland surface area variability, an index of wetland hydrodynamics that is linked to productivity, biodiversity, and value to waterfowl. Contrary to previous findings, our study shows that over the long term, lesser scaup are more than twice as likely to use permanent wetlands as they are semipermanent wetlands. The northern region of South Dakota's Prairie Coteau, which holds the highest density of hydrologically dynamic permanent wetlands, should be considered an area of conservation concern for lesser scaup. The criteria we identified may be used to identify important lesser scaup habitats in other regions of the Prairie Pothole Region.
Diversity And Distribution Of Mongolian Fish: Recent State, Trends And Studies, Yuri Dgebuadze, Bud Mendsaikhan, Ayurin Dulmaa
Diversity And Distribution Of Mongolian Fish: Recent State, Trends And Studies, Yuri Dgebuadze, Bud Mendsaikhan, Ayurin Dulmaa
Erforschung biologischer Ressourcen der Mongolei / Exploration into the Biological Resources of Mongolia, ISSN 0440-1298
The studies in recent years (2000-2011) have allowed to make more precise the list and ranges of Mongolian fish. This is connected with new findings as well as the continuing process of invasion of alien species. Climate change and increase of human impact transformed ranges and local distribution of fish during last 30 years. Bias on ratio of ecological guilds, number of pathological findings are increasing, and declining of local diversity, rate of growth and fecundity of many species of fish are observed. In the course of long-term observation was confirmed periodically drying of waters of the Central Asian Lake …