Debinski Diane M, Vannimwegen Ron E, Jakubauskas Mark E
Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, Iowa 50011 USA.
Ecol Appl. 2006 Feb;16(1):380-93. doi: 10.1890/04-1896.
Quantifying the manner in which ecological communities respond during a time of decreasing precipitation is a first step in understanding how they will respond to longer-term climate change. Here we coupled analysis of interannual variability in remotely sensed data with analyses of bird and butterfly community changes in montane meadow communities of the Greater Yellowstone Ecosystem. Landsat satellite imagery was used to classify these meadows into six types along a hydrological gradient. The northern portion of the ecosystem, or Gallatin region, has smaller mean patch sizes separated by ridges of mountains, whereas the southern portion of the ecosystem, or Teton region, has much larger patches within the Jackson Hole valley. Both support a similar suite of butterfly and bird species. The Gallatin region showed more overall among-year variation in the normalized difference vegetation index (NDVI) when meadow types were pooled within regions, perhaps because the patch sizes are smaller on average. Bird and butterfly communities showed significant relationships relative to meadow type and NDVI. We identified several key species that are tightly associated with specific meadow types along the hydrological gradient. Comparing taxonomic groups, fewer birds showed specific habitat affinities than butterflies, perhaps because birds are responding to differences in habitat structure among meadow types and using the landscape at a coarser scale than the butterflies. Comparing regions, the Teton region showed higher predictability of community assemblages as compared to the Gallatin region. The Gallatin region exhibited more significant temporal trends with respect to butterflies. Butterfly communities in wet meadows showed a distinctive shift along the hydrological gradient during a drought period (1997-2000). These results imply that the larger Teton meadows will show more predictable (i.e., static) species-habitat associations over the long term, but that the smaller Gallatin meadows may be an area that will exhibit the effects of global climate change faster.
量化生态群落降水减少期间的响应方式，是理解它们如何应对长期气候变化的第一步。在此，我们将遥感数据的年际变化分析与大黄石生态系统山地草甸群落中鸟类和蝴蝶群落变化分析相结合。利用陆地卫星图像，沿着水文梯度将这些草甸分为六种类型。生态系统的北部，即加勒廷地区，平均斑块面积较小，被山脉分隔，而生态系统的南部，即提顿地区，在杰克逊霍尔山谷内有大得多的斑块。两者都支持相似的蝴蝶和鸟类物种组合。当按区域汇总草甸类型时，加勒廷地区的归一化植被指数（NDVI）总体年际变化更大，这可能是因为平均斑块面积较小。鸟类和蝴蝶群落与草甸类型和NDVI显示出显著关系。我们确定了几种与沿水文梯度的特定草甸类型紧密相关的关键物种。比较分类群，与蝴蝶相比，表现出特定栖息地偏好的鸟类较少，这可能是因为鸟类对草甸类型间栖息地结构的差异做出反应，且利用景观的尺度比蝴蝶更粗。比较不同区域，提顿地区的群落组合预测性高于加勒廷地区。加勒廷地区的蝴蝶表现出更显著的时间趋势。在干旱期（1997 - 2000年），湿草甸中的蝴蝶群落在水文梯度上呈现出明显变化。这些结果表明，从长期来看，面积较大的提顿草甸将表现出更可预测（即稳定）的物种 - 栖息地关联，但面积较小的加勒廷草甸可能是一个更快展现全球气候变化影响的区域。
