Programa de Pós-Graduação Em Ecologia E Conservação, Universidade Federal de Sergipe - UFS, São Cristóvão, Sergipe, 49100-000, Brazil.
Programa de Capacitação Institucional, Instituto Nacional de Pesquisas da Amazônia - INPA, Manaus, Amazonas, 69067-375, Brazil.
Sci Rep. 2021 Aug 17;11(1):16670. doi: 10.1038/s41598-021-96216-8.
Predator-prey dynamics are some of the most important species' interactions in the natural structuring of communities, and are among the more complex ecological processes studied by ecologists. We measured predation risk using artificial lizard replicas to test two competing hypotheses regarding predation pressure in semi-arid environments: (1) predation risk is dependent on the habitat structural complexity; and (2) predation risk is dependent on seasonality. We placed 960 lizard replicas along three sites with different physical structures and in both dry and rainy seasons for seven consecutive days in a caatinga area in northeastern Brazil at Grota do Angico Natural Monument (GANM). Birds were responsible for the majority of attacks and more frequently on artificial lizards placed in trees. Attacks focused on the most vulnerable areas of the body (head and torso), proving that were perceived by predators as true prey items. We found that predation risk is not dependent on the habitat structural complexity, but rather dependent on the caatinga seasonality, with the overall attack rate being 19% higher in the dry season. Our study suggests that potential predation risk is highly context-dependent and that seasonality consistently drives of trophic interactions strength in the caatinga, an important ecological finding that could contribute to better understanding the complex evolution of predator-prey interactions within communities of animals living in different habitats.
捕食者-猎物动态是自然界中群落结构中最重要的物种相互作用之一，也是生态学家研究的较为复杂的生态过程之一。我们使用人工蜥蜴复制品来衡量捕食风险，以检验两个关于半干旱环境中捕食压力的竞争假设：（1）捕食风险取决于栖息地结构的复杂性；（2）捕食风险取决于季节性。我们在巴西东北部的加图安哥自然纪念碑（GANM）的三个具有不同物理结构的地点，并在旱季和雨季连续七天放置了 960 个蜥蜴复制品。鸟类是大多数攻击的罪魁祸首，并且更频繁地攻击放置在树上的人工蜥蜴。攻击集中在身体最脆弱的部位（头部和躯干），这证明了捕食者将其视为真正的猎物。我们发现，捕食风险不取决于栖息地结构的复杂性，而是取决于卡廷加的季节性，在旱季的总攻击率高出 19%。我们的研究表明，潜在的捕食风险高度依赖于环境，并且季节性始终是推动卡廷加中营养相互作用强度的因素，这是一个重要的生态发现，有助于更好地理解生活在不同栖息地的动物群落中捕食者-猎物相互作用的复杂演变。
