Data from: Movement propensity and ability correlate with ecological specialisation in European land snails: comparative analysis of a dispersal syndrome

Intra- and inter-specific differences in movement behaviour play an important role in the ecology and evolution of animals, particularly in fragmented landscapes. As a consequence of rarer and generally more fragmented habitat, and because dispersal tends to disrupt benefits brought by local adaptation, theory predicts that mobility and dispersal should be counter-selected in specialists. Using experimental data and phylogenetic comparative tools, we analysed movement propensity and capacity, as well as dispersal-related phenotypic traits, in controlled conditions in 20 species of European land snails from the Helicoidea superfamily. Costs of movement in terrestrial gastropods are among the highest in animals, which make them a potentially powerful model to test these predictions. Habitat specialists were indeed less likely to cross a boundary between a familiar and an unfamiliar substrate than generalists. They also had smaller feet, after accounting for size. Furthermore, exploring specialists were slower than generalists, and had more tortuous trajectories, leading them to stay closer to the familiar patch. Movement traits were generally evolutionary labile, but some were constrained by body size, a phylogenetically conserved trait. High specialisation and low dispersal ability are two traits often considered to increase species vulnerability to fragmentation, climate changes and extinction. This study confirms they should not be considered separately, due to their integration in a dispersal syndrome. Therefore, specialist species face double penalty under habitat loss and other environmental changes, making them more vulnerable to extinction and contributing to the biotic homogenization of communities.

动物运动行为的种内与种间差异，在动物生态学与演化进程中扮演着关键角色，在生境破碎化景观中这一作用尤为显著。鉴于生境愈发稀缺且普遍更为破碎，加之扩散往往会削弱局部适应所带来的收益，理论预测生境特化类群的运动能力与扩散能力将受到负向选择。本研究依托实验数据与系统发育比较分析工具，在可控实验条件下，对隶属于旋蜗牛总科（Helicoidea）的20种欧洲陆生蜗牛的运动倾向、运动能力，以及与扩散相关的表型性状开展了分析。陆生腹足类的运动代价位居动物界前列，这使其成为验证上述理论预测的极具潜力的模型类群。研究结果显示，生境特化种跨越熟悉与陌生基质间边界的概率确实低于广适种；在校正体型大小后，特化种的腹足尺寸也更小。此外，探索过程中的特化种移动速度慢于广适种，且运动轨迹更为曲折，使其更倾向于停留在熟悉的生境斑块内。运动性状整体上演化可塑性较高，但部分性状受体型这一系统发育保守性状的约束。高特化程度与低扩散能力这两类性状，通常被认为会提升物种对生境破碎化、气候变化以及灭绝事件的脆弱性。本研究证实，由于二者共同整合于扩散综合征之中，不应将这两类性状割裂看待。因此，在生境丧失与其他环境变化的影响下，特化物种面临双重代价，这使其灭绝风险进一步升高，并加剧了群落的生物均质化过程。