Winners and losers in human-made habitats: interspecific competition outcomes in two Neotropical vultures
Winners and losers in human-made habitats: interspecific competition outcomes in two Neotropical vultures
复制标题
DOI：
10.1111/j.1469-1795.2010.00352.x
复制
发表时间：
2010-08-01
影响因子：
3.4
通讯作者：
Donazar, J. A.
中科院分区：
文献类型：
--
作者：
Carrete, M.;Lambertucci, S. A.;Donazar, J. A.
了解物种共存的潜在因素是群落生态学的一个主要焦点。在处理本地物种和外来物种之间的竞争时，对“较弱”物种的竞争性排斥可能会对生物多样性保护产生影响。我们研究了种间的相互作用，在阿根廷南部的黑秃鹫Coragyps atratus和安第斯秃鹰秃鹫gryphus觅食。以前的研究表明，促进他们之间的相互作用。然而，在它们分布范围的大部分地区，这些物种直到最近才共存，当时黑秃鹫随着人类的发展扩大了它们的地理范围。因此，促进进程或隔离模式无法得到足够的微调，使其能够共存。我们的假设是，黑秃鹫和安第斯神鹰竞争食物资源，这种竞争的情况可以根据当地物种丰度和栖息地的人性化而改变。我们实验性地将绵羊尸体放置在两个不同程度的人类化栖息地中，以研究这些物种的觅食模式。这两个物种利用尸体具有相似的时间模式。然而，第一个到达的物种和优势种在两个栖息地不同，根据他们的丰度。虽然黑秃鹫并不能完全阻止安第斯神鹫的到来，但它们是进食的严重障碍。因此，虽然在尸体的优势等级可能与身体大小，尸体的消费是由物种丰度。我们的研究结果支持了这一假设，即一个“获胜”的物种的扩张可能会引发种间竞争与其他“失败者”的物种，对人类活动的负面反应时，他们变得丰富。虽然结果不是决定性的，但入侵和灭绝过程可能正在发生，它们可能对新世界清道夫行会的多样性（即丰富性和均匀性）产生严重后果。
Understanding the factors underlying species coexistence is a major focus in community ecology. When dealing with competition between native and exotic species, the competitive exclusion of the 'weaker' species can have consequences for biodiversity conservation. We examined interspecific interactions during foraging between black vultures Coragyps atratus and Andean condors Vultur gryphus in Southern Argentina. Previous studies suggest facilitatory interactions between them. However, in most parts of their distribution ranges, these species did not coexist until recently, when black vultures expanded their geographic range following human development. Thus, facilitatory processes or segregation patterns could not be fine-tuned enough to allow their coexistence. Our hypothesis is that black vultures and Andean condors compete for food resources, and that this competitive scenario can change depending on local species abundances and habitat humanization. We experimentally placed sheep carcasses in two habitats differing in degrees of humanization to study the foraging patterns in these species. Both species exploited carcasses with similar temporal patterns. However, the first to arrive and the dominant species were different in both habitats, according to their abundances. Although black vultures do not completely prevent the arrival of Andean condors to carcasses, they represent serious obstacles for feeding. Thus, while dominance hierarchy at carcasses could be related to body size, carcass consumption was determined by species abundance. Our results support the hypothesis that the expansion of a 'winning' species may trigger interspecific competition with other 'loser' species, with negative responses towards human activities when they became abundant. Although the results are not conclusive, invasion and extinction processes could be occurring and they can have serious consequences for the diversity (i.e. richness and evenness) of the New World scavenger guilds.