State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Beijing, People's Republic of China.
PLoS One. 2011;6(8):e23115. doi: 10.1371/journal.pone.0023115. Epub 2011 Aug 24.
Predicting species range shifts in response to climatic change is a central aspect of global change studies. An ever growing number of species have been modeled using a variety of species distribution models (SDMs). However, quantitative studies of the characteristics of range shifts are rare, predictions of range changes are hard to interpret, analyze and summarize, and comparisons between the various models are difficult to make when the number of species modeled is large. Maxent was used to model the distribution of 12 Abies spp. in China under current and possible future climate conditions. Two fuzzy set defined indices, range increment index (I) and range overlapping index (O), were used to quantify range shifts of the chosen species. Correlation analyses were used to test the relationships between these indices and species distribution characteristics. Our results show that Abies spp. range increments (I) were highly correlated with longitude, latitude, and mean roughness of their current distributions. Species overlapping (O) was moderately, or not, correlated with these parameters. Neither range increments nor overlapping showed any correlation with species prevalence. These fuzzy sets defined indices provide ideal measures of species range shifts because they are stable and threshold-free. They are reliable indices that allow large numbers of species to be described, modeled, and compared on a variety of taxonomic levels.
预测物种对气候变化的范围转移是全球变化研究的一个核心方面。越来越多的物种已经使用各种物种分布模型（SDM）进行了建模。然而，对范围转移特征的定量研究很少，范围变化的预测难以解释、分析和总结，并且当建模的物种数量很大时，很难对各种模型进行比较。Maxent 用于模拟中国 12 种冷杉属物种在当前和未来可能的气候条件下的分布。使用两个模糊集定义的指数，范围增量指数（I）和范围重叠指数（O），来量化所选物种的范围转移。相关性分析用于检验这些指数与物种分布特征之间的关系。我们的结果表明，冷杉属物种的范围增量（I）与经度、纬度和当前分布的平均粗糙度高度相关。物种重叠（O）与这些参数中度相关，或者不相关。范围增量和重叠都与物种流行度没有任何相关性。这些模糊集定义的指数提供了物种范围转移的理想衡量标准，因为它们是稳定的且没有阈值。它们是可靠的指数，可以在各种分类学水平上描述、建模和比较大量的物种。
