Impacts of insect herbivores on rare plant populations

摘要: Population-level impacts of insect herbivory on rare and endangered plants are poorly understood, being frequently suggested but seldom quantified. We compiled 37 studies from the primary literature encompassing 35 plant species at least 63 herbivore species, assessed patterns in effects herbivores populations vital rates. Only three directly quantified population size or growth rate, with vast majority instead extrapolating rates to size. Few (eight) studied experimentally, feeding guilds other than seed predators have been relatively neglected. Estimates population-level vary extremely widely, for many cause major reductions survivorship fecundity can even drive local extinctions. Four documented positive (plant-) density dependence attack, suggesting that may a stabilizing influence thus play role regulating Most reported oligophagous polyphagous, monophagous do exist, there was no detectable difference impact among specialization classes. Attack by escaped biocontrol agents sometimes significant effects, such cases appear uncommon. Because strongly suppress rates, we need know much more about what ecological evolutionary factors determine herbivores. suggest several ways which results research could inform conservation practices – example, possibility different management regimes under attack monophagous, oligophagous, polyphagous