Odum School of Ecology, University of Georgia, Athens, Georgia, United States of America.
PLoS One. 2013 Sep 18;8(9):e65101. doi: 10.1371/journal.pone.0065101. eCollection 2013.
Coffee agroforestry systems and secondary forests have been shown to support similar bird communities but comparing these habitat types are challenged by potential biases due to differences in detectability between habitats. Furthermore, seasonal dynamics may influence bird communities differently in different habitat types and therefore seasonal effects should be considered in comparisons. To address these issues, we incorporated seasonal effects and factors potentially affecting bird detectability into models to compare avian community composition and dynamics between coffee agroforests and secondary forest fragments. In particular, we modeled community composition and community dynamics of bird functional groups based on habitat type (coffee agroforest vs. secondary forest) and season while accounting for variation in capture probability (i.e. detectability). The models we used estimated capture probability to be similar between habitat types for each dietary guild, but omnivores had a lower capture probability than frugivores and insectivores. Although apparent species richness was higher in coffee agroforest than secondary forest, model results indicated that omnivores and insectivores were more common in secondary forest when accounting for heterogeneity in capture probability. Our results largely support the notion that shade-coffee can serve as a surrogate habitat for secondary forest with respect to avian communities. Small coffee agroforests embedded within the typical tropical countryside matrix of secondary forest patches and small-scale agriculture, therefore, may host avian communities that resemble those of surrounding secondary forest, and may serve as viable corridors linking patches of forest within these landscapes. This information is an important step toward effective landscape-scale conservation in Neotropical agricultural landscapes.
咖啡农林业系统和次生林已被证明支持相似的鸟类群落,但由于栖息地之间的可检测性差异,比较这些栖息地类型具有挑战性。此外,季节性动态可能会以不同的方式影响不同栖息地类型的鸟类群落,因此在比较时应考虑季节性影响。为了解决这些问题,我们将季节性影响和可能影响鸟类可检测性的因素纳入模型中,以比较咖啡农林业和次生林片段中的鸟类群落组成和动态。特别是,我们基于栖息地类型(咖啡农林业与次生林)和季节,对鸟类功能组的群落组成和群落动态进行建模,同时考虑了捕获概率(即可检测性)的变化。我们使用的模型估计每个食性群体的栖息地类型之间的捕获概率相似,但杂食动物的捕获概率低于食果动物和食虫动物。尽管咖啡农林业中的明显物种丰富度高于次生林,但在考虑捕获概率的异质性时,模型结果表明,杂食动物和食虫动物在次生林中更为常见。我们的结果在很大程度上支持了这样一种观点,即遮荫咖啡可以作为次生林的替代栖息地,就鸟类群落而言。因此,小的咖啡农林业嵌入在典型的热带乡村次生林斑块和小规模农业的矩阵中,可能会容纳类似于周围次生林的鸟类群落,并可能成为这些景观中森林斑块之间的可行走廊。这些信息是实现新热带农业景观有效景观尺度保护的重要一步。