Changes in species interactions across a 2.5 km elevation gradient: effects on plant migration in response to climate change
Changes in species interactions across a 2.5 km elevation gradient: effects on plant migration in response to climate change
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DOI：
10.1111/j.1365-2486.2010.02268.x
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发表时间：
2010-12-01
影响因子：
11.6
通讯作者：
Silman, Miles R.
中科院分区：
文献类型：
--
作者：
Hillyer, Rachel;Silman, Miles R.
预计安第斯山脉的气候变化将要求植物物种向山坡上迁移以避免灭绝。预测物种对气候变化的反应的核心是了解物种沿着环境梯度的分布。环境梯度经常被模拟为非生物的，但生物的相互作用可以发挥重要作用，在设置物种分布，丰度和生活史特征。生物相互作用也有可能影响物种对气候变化的反应，但它们大多仍然没有量化。在热带森林中长期研究的一个重要的相互作用是扩散后的种子捕食，已被证明会影响种群动态，群落结构和植物物种的多样性在时间和空间上。本文提出了一个比较种子捕食研究的24种热带树木在2.5公里的海拔梯度在秘鲁安第斯山脉和量化种子捕食变化的海拔梯度。然后，我们使用人口模型，以评估所观察到的种子捕食的变化对人口增长率的影响，在该地区观察到的温度升高。我们发现显着的物种之间的变化，在总种子捕食的主要种子捕食者的物种和一致的变化，种子捕食整个梯度。有一个显着的增加，种子存活率随着海拔的增加，这一趋势似乎是由调节种子捕食者通过自上而下的力量在低地让位于自下而上（生产力）的调节中，高海拔地区，导致在高海拔地区的树木的有效繁殖力增加了9倍。种子作物大小的这种潜在增加强烈影响了模拟的植物种群增长和种子传播距离，增加了气候变化下的种群迁移潜力。这些结果也表明，物种间的相互作用可以有与气候在物种对全球变化的反应。
Predicted climate change in the Andes will require plant species to migrate upslope to avoid extinction. Central to predictions of species responses to climate change is an understanding of species distributions along environmental gradients. Environmental gradients are frequently modelled as abiotic, but biotic interactions can play important roles in setting species distributions, abundances, and life history traits. Biotic interactions also have the potential to influence species responses to climate change, yet they remain mostly unquantified. An important interaction long studied in tropical forests is postdispersal seed predation which has been shown to affect the population dynamics, community structure, and diversity of plant species in time and space. This paper presents a comparative seed predation study of 24 species of tropical trees across a 2.5 km elevation gradient in the Peruvian Andes and quantifies seed predation variation across the elevational gradient. We then use demographic modelling to assess effects of the observed variation in seed predation on population growth rates in response to observed increasing temperatures in the area. We found marked variation among species in total seed predation depending on the major seed predator of the species and consistent changes in seed predation across the gradient. There was a significant increase in seed survival with increasing elevation, a trend that appears to be driven by regulation of seed predators via top-down forces in the lowlands giving way to bottom-up (productivity) regulation at mid- to high elevations, resulting in a ninefold increase in effective fecundity for trees at high elevations. This potential increase in seed crop size strongly affects modelled plant population growth and seed dispersal distances, increasing population migration potential in the face of climate change. These results also indicate that species interactions can have effects on par with climate in species responses to global change.