The influence of aquatic and riparian habitats on the composition of the local herpetofauna has not been studied extensively. We used redundancy analysis and multivariate ordination methods to evaluate the occurrence of semi-aquatic reptiles in south-eastern France, the Iberian Peninsula, and Morocco where the climate transitions from humid temperate to subtropical desert. All the semi-aquatic reptile species present in this region were studied, including two native turtles (Emys orbicularis and Mauremys leprosa), three native snakes (Natrix astreptophora, N. helvetica, and N. maura), and one introduced turtle (Trachemys scripta). We hypothesized that these species will vary in their responses to differences in the composition of riparian habitats (vegetative community and relative proportion of trees, shrubs, grasses, water and bare ground surface) along the aridity gradient in the region. We found that the habitat niche marginality and niche breadth varied widely across species and climatic regions, although most of the species display a greater habitat niche breadth in the transitional semi-arid belt. Mauremys leprosa and N. maura were the more generalist species, occupying a wide range of freshwater habitats, including streams associated with impoverished vegetation communities, characteristic of the arid southern Mediterranean region.

中文翻译：

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地中海西部干旱梯度上半水生爬行动物的栖息地占有率

水生和河岸栖息地对当地爬行动物组成的影响尚未得到广泛研究。我们使用冗余分析和多变量排序方法来评估半水生爬行动物在法国东南部、伊比利亚半岛和摩洛哥的发生，这些地区的气候从潮湿的温带过渡到亚热带沙漠。研究了该地区存在的所有半水生爬行动物物种，包括两种本地龟（Emys orbicularis和Mauremys leprosa）、三种本地蛇（Natrix asstreptophora、N. helvetica和N. maura）和一种引入龟（Trachemys scripta））。我们假设这些物种对沿该地区干旱梯度的河岸栖息地组成（植物群落和树木、灌木、草、水和裸露地表的相对比例）的差异的反应会有所不同。我们发现栖息地生态位边缘和生态位宽度在物种和气候区域之间差异很大，尽管大多数物种在过渡半干旱带中表现出更大的栖息地生态位宽度。Mauremys leprosa和N. maura是更普遍的物种，占据了广泛的淡水栖息地，包括与贫瘠植被群落相关的溪流，这是干旱的地中海南部地区的特征。