Simultaneous decline in Steppe Eagle (Aquila nipalensis) populations and Levant Sparrowhawk (Accipiter brevipes) reproductive success: coincidence or a hernobyl legacy?
| Autor: | Reuven Yosef, Lorenzo Fornasari |
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| Jazyk: | angličtina |
| Rok vydání: | 2004 |
| Předmět: | |
| Zdroj: | Ostrich: Journal of African Ornithology; Vol 75, No 1 (2004); 20-24 |
| ISSN: | 0030-6525 1727-947X |
| Popis: | Visual migration surveys, especially at bottlenecks, can be a vital tool to evaluate population fluctuations in environmentally sensitive species. Raptors are considered to be important bioindicators that can help identify environmental catastrophes. Substantial proportions of the global population of Steppe Eagles (Aquila nipalensis) and Levant Sparrowhawk (Accipiter brevipes) concentrate at Eilat, Israel, during the spring and autumn migrations, but counts from seven autumn and seven spring migration surveys indicate a constant decline in Steppe Eagle numbers. Further, the number of juveniles observed in these counts dropped steadily from 30% in the early 1980s, to 1.4% in 2000. The numbers observed at Eilat are well below the range of the numerical fluctuations observed in previous surveys. In Levant Sparrowhawks, no decline in total numbers is evident, but a significant change in the adult to juvenile age ratio was noted between the population trapped in the 1980s and that sampled in the late 1990s. The cumulative evidence of the decrease in the total numbers of Steppe Eagles, the decreasing proportion of subadults within the population, and the decrease in adult:young ratio in the Levant Sparrowhawk population trapped leads us to suggest that the Chernobyl accident on 26 April 1986 may have negatively affected wildlife populations, not only to the west with the spread of the radio-active plume, but farther east than previously assumed.Ostrich 2004, 75(1&2): 20–24 |
| Databáze: | OpenAIRE |
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