Habitat loss and raptor predation: disentangling long– and short–term causes of red grouse declines
Habitat loss and raptor predation: disentangling long– and short–term causes of red grouse declines
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栖息地丧失和猛禽捕食：解开红松鸡数量下降的长期和短期原因
DOI：
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发表时间：
2000
期刊：
影响因子：
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通讯作者：
P. Hudson
中科院分区：
文献类型：
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作者：
S. Thirgood;S. Redpath;D. Haydon;P. Rothery;I. Newton;P. Hudson
世纪，在英国射杀的红松鸡（Lagopus lagopus scoticus）数量下降了50%。这一下降与适宜栖息地面积的减少和一些鸟类捕食者种群的恢复相吻合。在这里，我们使用长期记录的射击袋和大规模的猛禽密度的操纵解开栖息地丧失和猛禽捕食松鸡种群的影响。在苏格兰南部的朗霍尔姆摩尔的埃斯克代尔一半上收获的松鸡数量在1913年至1990年期间显著下降，而从1950年至1990年整个摩尔的松鸡袋呈现出几乎相同但不显著的趋势。母鸡harriers（马戏团cyaneus）和游隼（隼peregrinus）缺席或在低密度繁殖在这片摩尔在此期间，但石楠占主导地位的植被下降了48%，1948年至1988年。1990年，朗霍尔姆摩尔保护区内的鹞和游隼繁殖数量达到了很高的水平，而松鸡密度和松鸡袋数逐年下降，直到1998年放弃拍摄。1996年根据1950-1990年期间袋的模式预测朗霍尔姆沼泽上的松鸡袋的峰值得到了1997年附近两个沼泽上观察到的峰值的支持，这两个沼泽以前与朗霍尔姆摩尔同步循环。这项研究表明，虽然松鸡袋的长期下降最有可能是由于栖息地的丧失，高水平的猛禽捕食随后限制了松鸡种群，并抑制了一个周期。因此，这项研究提供了支持的理论模型预测，通才捕食者可能会抑制猎物种群的周期。
The number of red grouse (Lagopus lagopus scoticus) shot in the UK has declined by 50% during the 20th century. This decline has coincided with reductions in the area of suitable habitat and recoveries in the populations of some avian predators. Here we use long–term records of shooting bags and a large–scale manipulation of raptor density to disentangle the effects of habitat loss and raptor predation on grouse populations. The numbers of grouse harvested on the Eskdale half of Langholm Moor in southern Scotland declined significantly during 1913–1990 and grouse bags from the whole moor from 1950 to 1990 exhibited an almost identical but non–significant trend. Hen harriers (Circus cyaneus) and peregrine falcons (Falco peregrinus) were absent or bred at low densities on this moor throughout this period but heather–dominant vegetation declined by 48% between 1948 and 1988. Harrier and peregrine breeding numbers on Langholm Moor increased to high levels following protection in 1990 whilst grouse density and grouse bags declined year after year until shooting was abandoned in 1998. The prediction of a peak in grouse bags on Langholm Moor in 1996 based on the patterns of bags during 1950–1990 was supported by the observed peaks in 1997 on two nearby moors with few raptors which formerly cycled in synchrony with Langholm Moor. This study demonstrates that, whilst long–term declines in grouse bags were most probably due to habitat loss, high levels of raptor predation subsequently limited the grouse population and suppressed a cycle. This study thus offers support to theoretical models which predict that generalist predators may suppress cycles in prey populations.