Center for Conservation Biology, Department of Biology, Stanford University, Stanford, CA 94305, USA.
Proc Natl Acad Sci U S A. 2011 Dec 27;108(52):21134-9. doi: 10.1073/pnas.1118276108. Epub 2011 Dec 12.
The consequences of biodiversity decline in intensified agricultural landscapes hinge on surviving biotic assemblages. Maintaining crucial ecosystem processes and services requires resilience to natural and anthropogenic disturbances. However, the resilience and stability of surviving biological communities remain poorly quantified. From a 10-y dataset comprising 2,880 bird censuses across a land-use gradient, we present three key findings concerning the resilience and stability of Costa Rican bird communities. First, seed dispersing, insect eating, and pollinating guilds were more resilient to low-intensity land use than high-intensity land use. Compared with forest assemblages, bird abundance, species richness, and diversity were all ~15% lower in low-intensity land use and ~50% lower in high-intensity land use. Second, patterns in species richness generally correlated with patterns in stability: guilds exhibited less variation in abundance in low-intensity land use than in high-intensity land use. Finally, interspecific differences in reaction to environmental change (response diversity) and possibly the portfolio effect, but not negative covariance of species abundances, conferred resilience and stability. These findings point to the changes needed in agricultural production practices in the tropics to better sustain bird communities and, possibly, the functional and service roles that they play.
在集约化农业景观中，生物多样性减少的后果取决于幸存的生物组合。维持关键的生态系统过程和服务需要对自然和人为干扰具有弹性。然而，幸存的生物群落的弹性和稳定性仍未得到充分量化。从一个包含 10 年数据的数据集，其中包括在土地利用梯度上进行的 2880 次鸟类普查，我们提出了关于哥斯达黎加鸟类群落的弹性和稳定性的三个关键发现。首先，种子传播、食虫和授粉类群比高强度土地利用更能适应低强度土地利用。与森林组合相比，低强度土地利用中的鸟类数量、物种丰富度和多样性都低了约 15%，而高强度土地利用中的鸟类数量、物种丰富度和多样性则低了约 50%。其次，物种丰富度的模式通常与稳定性的模式相关：在低强度土地利用中，类群的丰度变化比高强度土地利用中要小。最后，种间对环境变化的反应差异（反应多样性）以及可能的投资组合效应，而不是物种丰度的负协方差，赋予了弹性和稳定性。这些发现指出了热带地区农业生产实践需要进行的改变，以更好地维持鸟类群落，并可能维持它们所扮演的功能和服务角色。
