The conversion of tropical habitats has dramatic implications on biodiversity and represents one of the greatest conservation challenges of our time. Seasonally Dry Tropical Forests (SDTF), which are disjointly distributed throughout the Neotropics, are especially susceptible to human activities. The Caatinga Dry Forest, located in the semi-arid interior of northeastern Brazil, represents not only the largest and most biologically diverse nucleus of SDTF, but also the world’s most densely populated semi-arid region, with ever-growing pressure on its natural resources. To prevent illegal logging, conservation agencies looked at forest management, where an area is divided in smaller stands which are gradually logged and allowed to regrow for a period of time, when a new cutting cycle should reinitiate. The impacts of these management schemes on biodiversity, however, remain largely untested. We conducted standardized avian surveys to evaluate the effects of forest management on the avian community at a 1,670 ha privately-owned property located on the Chapada do Araripe, northeastern Brazil. This area was divided in 22 forest stands, half of which had already been logged at the time of our sampling, creating a gradient of logged and natural forests and an 11-yr chrono-sequence of forest regeneration. Our results show that logged areas present fewer individuals, fewer species, and different avian assemblages than unlogged forests. Such differences are mostly driven by forest-dependent species, which were overwhelmingly affected by forest management. Our results show that although logged forests tend to recover its height after a decade, they do not recover the originally forest cover, measured by the Normalized Difference Vegetation Index. Likewise, decade-long recovering stands continue to show lower species richness, lower bird abundance, and different avian composition than unlogged forests. We identified a set of bird species that are more affected by forest management (ecological losers) and a group of birds that apparently benefit from the referred changes in land use (ecological winners). We conclude that completely managing an entire area may cause the extirpation of several forest-dependent species. We therefore suggest keeping logged and unlogged plots intermingled, to avoid local extinctions and the complete modification of the original avifauna.

中文翻译：

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森林管理对巴西旱林鸟类的影响

热带栖息地的转变对生物多样性具有重大影响，是我们这个时代最大的保护挑战之一。季节性干旱热带森林 (SDTF) 不连续分布在整个新热带地区，特别容易受到人类活动的影响。卡廷加干林位于巴西东北部半干旱内陆，不仅是 SDTF 最大、生物多样性最丰富的核心，也是世界上人口最稠密的半干旱地区，其自然资源压力不断增加. 为了防止非法采伐，保护机构研究了森林管理，将一个区域划分为较小的林分，这些林分逐渐被砍伐并允许重新生长一段时间，当新的砍伐周期应该重新开始时。然而，这些管理计划对生物多样性的影响在很大程度上仍未得到检验。我们在位于巴西东北部 Chapada do Araripe 的 1,670 公顷私有财产中进行了标准化的鸟类调查，以评估森林管理对鸟类社区的影响。该地区被划分为 22 个林分，其中一半在我们采样时已经被采伐，形成了一个采伐和天然林的梯度以及一个 11 年的森林更新年代序列。我们的结果表明，与未砍伐的森林相比，砍伐地区的个体、物种和不同的鸟类组合更少。这种差异主要是由依赖森林的物种造成的，而这些物种在很大程度上受到森林管理的影响。我们的结果表明，虽然砍伐的森林在十年后往往会恢复其高度，它们不会恢复原始森林覆盖率，由归一化差异植被指数衡量。同样，与未砍伐的森林相比，长达十年的恢复林继续显示出较低的物种丰富度、较低的鸟类数量和不同的鸟类组成。我们确定了一组受森林管理影响较大的鸟类（生态失败者）和一组明显受益于所提及的土地利用变化的鸟类（生态赢家）。我们得出结论，完全管理整个地区可能会导致几种依赖森林的物种灭绝。因此，我们建议将记录和未记录的地块混合在一起，以避免局部灭绝和原始鸟类的完全改变。与未砍伐的森林相比，长达十年的恢复林继续显示出较低的物种丰富度、较低的鸟类数量和不同的鸟类组成。我们确定了一组受森林管理影响较大的鸟类（生态失败者）和一组明显受益于所提及的土地利用变化的鸟类（生态赢家）。我们得出结论，完全管理整个地区可能会导致几种依赖森林的物种灭绝。因此，我们建议将记录和未记录的地块混合在一起，以避免局部灭绝和原始鸟类的完全改变。与未砍伐的森林相比，长达十年的恢复林继续显示出较低的物种丰富度、较低的鸟类数量和不同的鸟类组成。我们确定了一组受森林管理影响较大的鸟类（生态失败者）和一组明显受益于所提及的土地利用变化的鸟类（生态赢家）。我们得出结论，完全管理整个地区可能会导致几种依赖森林的物种灭绝。因此，我们建议将记录和未记录的地块混合在一起，以避免局部灭绝和原始鸟类的完全改变。我们确定了一组受森林管理影响较大的鸟类（生态失败者）和一组明显受益于所提及的土地利用变化的鸟类（生态赢家）。我们得出结论，完全管理整个地区可能会导致几种依赖森林的物种灭绝。因此，我们建议将记录和未记录的地块混合在一起，以避免局部灭绝和原始鸟类的完全改变。我们确定了一组受森林管理影响较大的鸟类（生态失败者）和一组明显受益于所提及的土地利用变化的鸟类（生态赢家）。我们得出结论，完全管理整个地区可能会导致几种依赖森林的物种灭绝。因此，我们建议将记录和未记录的地块混合在一起，以避免局部灭绝和原始鸟类的完全改变。