Newmark William D
Utah Museum of Natural History, University of Utah, 1390 E. Presidents Circle, Salt Lake City, UT 84112, USA.
Conserv Biol. 2006 Feb;20(1):122-34. doi: 10.1111/j.1523-1739.2005.00273.x.
I compared understory bird community structure and composition among primary, slightly disturbed, and moderately disturbed forest in the East Usambara Mountains in Tanzania. Comparisons were conducted at two spatiotemporal scales: short term, conducted in 1999 and 2000, in which treatments (disturbance levels) were replicated, and long term, conducted from 1989-2004 along the same disturbance gradient of a subset of the short-term sites. I used capture-recapture models to assess the probability of detection and estimate species richness and population growth rates. The probability of detection of species did not vary significantly among disturbance levels but did vary significantly among species. Over the short- and long-term surveys, estimated species richness did not vary significantly among disturbance levels. Temporal variability in estimated species richness and the relative abundance of guilds did vary significantly among disturbance levels yet was contingent on survey length. The coefficient of variation in species richness over the short-term survey was <5% across all disturbance levels, whereas over the long-term survey it was 35% in slightly disturbed forest, 11% in moderately disturbed forest, and 0% in primary forest. In the short-term survey, zero of seven feeding guilds varied significantly in relative abundance among disturbance levels, whereas over the long-term survey four of seven (57%) feeding guilds did so. Terrestrial insectivores were most adversely affected by forest disturbance. Population growth rates (lamda) between 1989 and 2004 for the more common species of terrestrial insectivores did not vary significantly among disturbance levels and for these species were significantly < or = 1.00, indicating the recovery time for terrestrial insectivores in slightly and moderately disturbed forest is very long. These results illustrate the importance of long-term studies in assessing ecological impacts of forest disturbance and the importance of protecting primary forest in the Eastern Arc Mountains.
我比较了坦桑尼亚东乌桑巴拉山脉中原始森林、轻度干扰森林和中度干扰森林林下鸟类群落的结构和组成。比较在两个时空尺度上进行：短期比较于1999年和2000年开展，其中各处理（干扰水平）进行了重复；长期比较于1989年至2004年沿着短期研究地点子集的相同干扰梯度进行。我使用捕获再捕获模型来评估检测概率，并估计物种丰富度和种群增长率。物种的检测概率在不同干扰水平之间没有显著差异，但在不同物种之间存在显著差异。在短期和长期调查中，估计的物种丰富度在不同干扰水平之间没有显著差异。估计的物种丰富度和鸟类功能类群相对丰度的时间变异性在不同干扰水平之间确实存在显著差异，但取决于调查长度。在短期调查中，所有干扰水平下物种丰富度的变异系数均<5%，而在长期调查中，轻度干扰森林中的变异系数为35%，中度干扰森林中为11%，原始森林中为0%。在短期调查中，七个取食功能类群中没有一个在不同干扰水平下的相对丰度有显著变化，而在长期调查中，七个取食功能类群中有四个（57%）出现了这种情况。陆生食虫鸟类受森林干扰的影响最为严重。1989年至2004年期间，较常见的陆生食虫鸟类物种的种群增长率（λ）在不同干扰水平之间没有显著差异，且这些物种的λ显著<或=1.00，这表明轻度和中度干扰森林中陆生食虫鸟类的恢复时间非常长。这些结果说明了长期研究在评估森林干扰的生态影响方面的重要性，以及保护东弧山脉原始森林的重要性。
