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（substrate），这些基质对其运动表现（locomotor performance）具有重要影响。生境改造（habitat modification）可改变可供动物运动的基质类型。具体而言，城市区域新增了诸多人工基质，但这类新型地表对动物运动的影响却鲜有研究。
2. 本研究针对安乐蜥属（Anolis）的两个物种（A. cristatellus与A. stratulus），在倾斜度与表面粗糙度各异的基质上评估其运动表现。粗糙基质模拟了天然森林生境中典型的树干与树枝，而光滑垂直基质则还原了人为改造生境中人工地表（如立柱、墙体）的特性。随后我们通过观察蜥蜴的生境利用行为，检验生境限制假说（habitat constraint hypothesis）：即蜥蜴应更频繁地占据其运动表现更佳的生境区域。
3. 基质倾斜度升高、表面粗糙度降低均会导致蜥蜴运动速度下降。A. cristatellus与A. stratulus均在光滑垂直基质上运动速度最慢，其中A. cristatellus在该基质上频繁打滑、跌落。与假说预测相悖的是，两种安乐蜥在野外均频繁使用光滑垂直基质。尽管A. cristatellus在光滑垂直测试跑道上的表现不如A. stratulus，但其在人为改造生境中仍有73%的时间占据人工基质。因此我们判定，针对该类人为改造生境中的安乐蜥，生境限制假说并不成立。
4. 尽管A. cristatellus在光滑垂直测试跑道上的整体表现不佳，但其存在显著的形态-运动表现关联（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A. stratulus在光滑垂直基质上的表现优于A. cristatellus，因此可能并未面临相同的选择压力（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固有的形态-运动表现-生境利用关联。这或许会引发部分物种种群选择压力的变化，进而影响它们在城市等人为改造生境中的定居与存续能力。