Upper thermal limits predict herpetofauna responses to forest edge and cover

Amphibians and reptiles are sensitive to changes in the thermal environment, which varies considerably in human-modified landscapes. Although it is known that thermal traits of species influence their distribution in modified landscapes, how herpetofauna respond specifically to shifts in ambient temperature along forest edges remains unclear. This may be because most studies focus on local-scale metrics of edge exposure, which only account for a single edge or habitat patch. We predicted that accounting for the combined effect of multiple habitat edges in a landscape would best explain herpetofaunal response to thermally-mediated edge effects. We (1) surveyed herpetofauna at two lowland, fragmented forest sites in central Colombia, (2) measured the critical thermal maximum (CTmax) of the species sampled, (3) measured their edge exposure at both local and landscape scales, and (4) created a thermal profile of the landscape itself. We found that species with low CTmax occurred both furthe..., Animal data (included here) were collected in the field and lab. Landscape data were derived from the vegetation density map (inlcuded here) either directly (tree cover) or using the BioFrag edge response software, available on GitHub., Summary data may be viewed in Excel and R, whereas spatial data may be viewed in R or GIS software such as ArcMap or QGIS.

两栖类与爬行类对热环境变化极为敏感，而在受人类活动改造的景观中，热环境的变化幅度往往较大。尽管已有研究证实物种的热性状会影响其在人为改造景观中的分布格局，但两栖爬行动物区系（herpetofauna）沿林缘的环境温度变化具体作出何种响应，目前仍不明确。这一认知缺口的成因，可能在于多数现有研究仅关注局域尺度的边缘暴露度指标，且仅考虑单一林缘或生境斑块。我们推测，若将景观内多个生境边缘的联合效应纳入考量，将能更精准地解释两栖爬行动物区系对热介导边缘效应的响应。本研究通过以下四项工作展开探究：(1) 在哥伦比亚中部两处低地碎片化森林样地中开展两栖爬行动物区系调查；(2) 测定所采样物种的临界热最大值（critical thermal maximum, CTmax）；(3) 从局域与景观两个尺度测定其边缘暴露度；(4) 构建研究区域的热环境剖面。研究发现，临界热最大值较低的物种多分布于…… 本研究的动物数据采集自野外与实验室；景观数据则直接源自植被密度图（已附于此）中的林冠覆盖率信息，或通过GitHub平台开源的BioFrag边缘响应软件获取。汇总数据可通过Excel与R语言查看，空间数据则可通过R语言或ArcMap、QGIS等地理信息系统（GIS）软件查看。