Data from: City slickers: poor performance does not deter Anolis lizards from using artificial substrates in human-modified habitats

1. As animals move through their environments they encounter a variety of substrates, which have important effects on their locomotor performance. Habitat modification can alter the types of substrates available for locomotion. In particular, many types of artificial substrates have been added to urban areas, but effects of these novel surfaces on animal locomotion are little-known. 2. In this study, we assessed locomotor performance of two Anolis lizard species (A. cristatellus and A. stratulus) on substrates that varied in inclination and surface roughness. Rough substrates represented the tree trunks and branches typically used in natural forest habitats, whereas smooth, vertical substrates captured the qualities of artificial surfaces, such as posts and walls, available in human-modified habitats. We then observed habitat use to test the habitat constraint hypothesis — that lizards should more frequently occupy portions of the habitat in which they perform better. 3. Increased inclination and decreased surface roughness caused lizards to run slower. Both A. cristatellus and A. stratulus ran slowest on the smooth, vertical surface, and A. cristatellus often slipped and fell on this surface. In contrast to predictions, both species frequently used smooth, vertical substrates in the wild. Anolis cristatellus occupied artificial substrates 73% of the time in human-modified habitats despite performing worse than A. stratulus on the smooth, vertical track. We therefore rejected the habitat constraint hypothesis for anoles in these human-modified habitats. 4. Despite overall poor performance on the smooth, vertical track, A. cristatellus had a significant morphology-performance relationship that supports the prediction that selection should favor smaller lizards with relatively longer limbs in human-modified habitats. The smaller-bodied A. stratulus performed better than A. cristatellus on smooth, vertical substrates and therefore may not be exposed to the same selective pressures. 5. We contend that habitat modification by humans may alter morphology-performance-habitat use relationships found in natural habitats. This may lead to changes in selective pressures for some species, which may influence their ability to occupy human-modified habitats such as cities.1. 动物在环境中移动时会接触到多种基质（substrates），这些基质对其运动表现（locomotor performance）具有关键影响。生境改造可改变可供动物进行运动的基质类型。当前已有多种人工基质被引入城市区域，但这类新型地表对动物运动的影响仍知之甚少。 2. 本研究针对安乐蜥属（Anolis）的两个物种——冠安乐蜥（A. cristatellus）与横纹安乐蜥（A. stratulus），在倾斜度与表面粗糙度（surface roughness）各异的基质上开展了运动表现评估。粗糙基质模拟了天然森林生境中典型的树干与枝条，而光滑垂直基质则复刻了人为改造生境中立柱、墙体等人工地表的特性。随后我们通过观察蜥蜴的生境利用情况，对生境约束假说（habitat constraint hypothesis）进行检验：该假说预测蜥蜴会更频繁地占据自身运动表现更优的生境区域。 3. 基质倾斜度升高与表面粗糙度降低均会导致蜥蜴运动速度下降。冠安乐蜥与横纹安乐蜥均在光滑垂直基质上运动速度最慢，且冠安乐蜥在该基质上常出现打滑与摔倒现象。与假说预测相悖的是，两个物种在野外均频繁使用光滑垂直基质。尽管冠安乐蜥在光滑垂直跑道上的运动表现差于横纹安乐蜥，但其在人为改造生境中仍有73%的时间占据人工基质。因此我们拒绝了该类安乐蜥在人为改造生境中的生境约束假说。 4. 尽管冠安乐蜥在光滑垂直跑道上的整体运动表现不佳，但其仍存在显著的形态-性能关联（morphology-performance relationship），这支持了“人为改造生境中自然选择应青睐肢体相对更长的小型蜥蜴”这一预测。体型更小的横纹安乐蜥在光滑垂直基质上的运动表现优于冠安乐蜥，因此其可能未承受同等的选择压力（selective pressures）。 5. 我们认为，人类的生境改造活动可能会改变天然生境中存在的形态-性能-生境利用三者间的关联。这可能会导致部分物种面临的选择压力发生改变，进而影响它们在城市等人为改造生境中的生存与定居能力。