Rapid latitudinal range expansion at cold limits unlikely for temperate understory forest plants
Rapid latitudinal range expansion at cold limits unlikely for temperate understory forest plants
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温带林下森林植物不太可能在寒冷极限下快速扩展纬度范围
DOI：
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发表时间：
2016
期刊：
影响因子：
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通讯作者：
S. Blois
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作者：
Frieda Beauregard;S. Blois
我们询问气候变暖是否可能引发北美东北部温带-寒带森林交错带林下植物的范围迅速向北扩张。我们通过详细分析寒冷地区边缘的当代居住模式并寻找与气候或其他环境（例如土壤）限制一致的模式来回答这个问题。我们首先确定每个物种已实现的生长度日生态位，以在该生态位的中央、尾部或边缘之外的样本区域进行采样。我们基于 11 个非气候变量对每个物种的栖息地适宜性进行建模，并比较不同区域中合适地点的可用性和占用率，假设气候限制可能导致其他合适地点的占用率或丰富度减少至范围限制。我们还检查了范围限制内向温暖小气候条件转变的证据，作为气候限制的潜在指示。根据我们的栖息地模型，我们发现对于大多数物种来说，这三个区域中合适地点的可用性下降，而范围边缘合适地点的占用率增加，并且丰度没有显着变化。一些物种迁移到了小气候条件温暖的地区；其中一些也大量下降，表明气候限制。然而，我们的结论是，对于大多数研究的物种来说，合适的地点似乎决定了分布的北部边缘，因此，变暖可能不一定会导致近期范围的扩大。
We ask whether climate warming will be likely to trigger rapid northward range expansion for understory plants in the northeastern forests of North America at the temperate–boreal forest ecotone. We answer this question through a detailed analysis of contemporary occupancy patterns at cold range edges and by looking for patterns consistent with climate or other environmental (e.g., edaphic) limitations. We first identify each species' realized growing degree-day niche to sample zones central, at the tail, or beyond the edge of this niche. We model habitat suitability, based on 11 nonclimate variables, for each species, and compare the availability of, and occupancy on, suitable sites across zones, with the assumption that a limiting climate is likely to result in decreased occupancy or abundance on otherwise suitable sites toward the range limit. We also check for evidence of shifts to warm microclimate conditions at the range limit as a potential indication of climate limitations. Based on our habitat models, we find that the availability of suitable sites declines across these three zones for most species, while occupancy increases on suitable sites at range edge, and abundance does not vary significantly. Some species shifted to sites with warm microclimate conditions; of these, several also declined in abundance suggesting climate limitations. We conclude, however, that for most species studied, suitable site availability appears to determine the northern edges of distribution and, consequently, warming may not necessarily lead to near-term range expansions.