A meta‐analysis of insularity effects on herbivory and plant defences

Aim: Plants on islands are often subjected to lower levels of herbivory relative to those at mainland sites. As a consequence, island plants are predicted to exhibit lower levels of physical and chemical defences, which renders them more susceptible to introduced herbivores. Yet, instances of high pressure by superabundant herbivores native to islands have been reported in many insular systems, which presumably would result in heightened plant defences. To date, no quantitative review has been conducted to determine how common these contrasting patterns are and their implications for the evolution of plant defences.

Location: Islands worldwide

Taxon: Plants, insects, mammals

Methods: We conducted a meta-analysis of insularity effects on herbivory and plant defences by including studies that conducted island-mainland comparisons of the same plant species in both environments (90% of cases), or insular endemics vs. mainland congeners (10% of cases). We tested for differences betw...

研究目标：相较于大陆生境的植物，岛屿植物通常面临更低的植食压力。据此，学界通常推测岛屿植物的物理与化学防御水平会更低，这使其更易遭受外来植食动物的侵害。然而，诸多岛屿生态系统中已有本土植食动物种群过剩、形成高强度植食压力的案例被报道，这类情况按理应当会促使植物防御水平提升。截至目前，尚无定量综述研究阐明这类对立模式的普遍性，以及其对植物防御演化的启示。
研究区域：全球范围内的岛屿
研究类群：植物、昆虫、哺乳动物
研究方法：本研究针对岛屿效应在植食压力与植物防御中的作用开展元分析（meta-analysis），纳入的研究包含两类：一是在岛屿与大陆生境中对同一植物物种进行对比的研究（占总案例的90%），二是岛屿特有种与大陆近缘种的对比研究（占总案例的10%）。本研究旨在检验……