Global amphibian declines: sorting the hypotheses
Global amphibian declines: sorting the hypotheses
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DOI：
10.1046/j.1472-4642.2003.00012.x
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发表时间：
2003-03-01
影响因子：
4.6
通讯作者：
Storfer, A
中科院分区：
文献类型：
--
作者：
Collins, JP;Storfer, A
关于畸形两栖动物和全球两栖动物减少的报道引起了公众的关注，特别是因为两栖动物被认为是整体环境健康的指标物种。这个话题也引起了科学界的关注，因为对于什么导致两栖动物减少的问题没有明显的简单答案。几种人为因素的复杂相互作用可能在起作用，因此，了解两栖动物的下降可能作为一个模型，了解物种的下降一般。虽然我们得到的答案比我们希望的要少，但有六个主要的假设，我们可以分为两类。对于第一类假说，外来物种，过度开发和土地利用的变化，我们有一个很好的理解的生态机制下降的基础上，这些原因对两栖动物种群产生了负面影响超过世纪。然而，随着科学家们开始注意到全球两栖动物的减少，这些负面影响的程度是否在20世纪80年代有所增加，这一问题仍然存在。此外，这些问题的补救措施并不简单。对于第二类假设，全球变化（包括紫外线辐射和全球气候变化），污染物和新出现的传染病，我们有一个穷人，但提高了解如何每一个可能导致下降。第二类因素涉及复杂和微妙的机械基础，多个生态和进化变量之间可能的相互作用。它们也可能与第一类假说相互作用。与II类假说相关的可疑机制是相对较新的，至少可以追溯到世纪中期。这些原因是独立地起作用，还是与预先存在的第一类假设的消极力量共同作用，使两栖动物的下降速度增加到引起全球关注的水平？我们需要更多的研究，将这两类假设的潜在机制与两栖动物种群规模和物种数量的定量变化联系起来。在这一任务中向前迈出的重要一步是澄清各种原因单独或共同起作用的假设和条件。
Reports of malformed amphibians and global amphibian declines have led to public concern, particularly because amphibians are thought to be indicator species of overall environmental health. The topic also draws scientific attention because there is no obvious, simple answer to the question of what is causing amphibian declines? Complex interactions of several anthropogenic factors are probably at work, and understanding amphibian declines may thus serve as a model for understanding species declines in general. While we have fewer answers than we would like, there are six leading hypotheses that we sort into two classes. For class I hypotheses, alien species, over-exploitation and land use change, we have a good understanding of the ecological mechanisms underlying declines; these causes have affected amphibian populations negatively for more than a century. However, the question remains as to whether the magnitude of these negative effects increased in the 1980s, as scientists began to notice a global decline of amphibians. Further, remedies for these problems are not simple. For class II hypotheses, global change (including UV radiation and global climate change), contaminants and emerging infectious diseases we have a poor, but improving understanding of how each might cause declines. Class II factors involve complex and subtle mechanistic underpinnings, with probable interactions among multiple ecological and evolutionary variables. They may also interact with class I hypotheses. Suspected mechanisms associated with class II hypotheses are relatively recent, dating from at least the middle of the 20th century. Did these causes act independently or in concert with pre-existing negative forces of class I hypotheses to increase the rate of amphibian declines to a level that drew global attention? We need more studies that connect the suspected mechanisms underlying both classes of hypotheses with quantitative changes in amphibian population sizes and species numbers. An important step forward in this task is clarifying the hypotheses and conditions under which the various causes operate alone or together.