Calcareous defense structures of prey mediate the effects of predation and biotic resistance towards the tropics

Aims The importance of biotic interactions in creating and maintaining diversity is expected to increase toward low latitudes. However, the way in which predation affects diversity, can depend on how predators mediate competitive interactions and also on defensive traits of prey. Here we assessed the role of physical defences of prey to escape predation and how the importance of predation on community structure and diversity changes across latitude. Location Six sites, in three regions distributed across 45 degrees of latitude in the Atlantic Ocean: a tropical region in Angola, a subtropical region in Brazil and a temperate region in Wales-UK. Methods We manipulated predation on marine sessile communities, using exclusion cages and assessed community parameters, including their susceptibility to biological invasion during early and advanced succession. Results Predation was more intense in the tropics and in advanced communities suggesting that predation effects inc...研究目的 生物相互作用（biotic interactions）在构建并维持生物多样性过程中的重要性随纬度降低而愈发凸显。然而，捕食作用（predation）对生物多样性的影响，既取决于捕食者如何介导种间竞争相互作用，也与猎物的防御性状（defensive traits）密切相关。本研究旨在评估猎物的物理防御（physical defences）在逃避捕食中的作用，以及捕食作用对群落结构与多样性的重要性如何随纬度梯度发生变化。 研究区域 本研究在大西洋海域沿45度纬度梯度设置了3个区域共6个采样点：分别为安哥拉的热带海域、巴西的亚热带海域以及英国威尔士的温带海域。 研究方法 本研究通过捕食排除笼（exclusion cage）操控海洋固着群落（marine sessile communities）的捕食压力，并评估了群落的多项参数，包括其在早期演替与顶级演替阶段对生物入侵的易感性。 研究结果 热带海域与顶级演替群落中的捕食作用更为强烈，表明捕食效应的……