Counteracting effects of a non-native prey on demography of a native predator culminate in positive population growth

Identifying impacts of non-native species on native populations is central to conservation and ecology. While effects of non-native predators on native prey populations have recently received much attention, impacts of introduced prey on native predator populations are less understood. Non-native prey can influence predator behavior and demography through direct and indirect pathways, yet quantitative assessments of the relative impacts of multiple, potentially counteracting, effects on native predator population growth remain scarce. Using ≈20 years of range-wide monitoring data, we tested for effects of a recently-introduced, rapidly-spreading non-native prey species (Pomacea maculata) on the behavior and demography of the endangered snail kite (Rostrhamus sociabilis). Previous studies found that food-handling difficulties caused by the large size of P. maculata (relative to the native P. paludosa) can lead to energetic deficiencies in juvenile kites, suggesting the potential for evol...探明外来物种对本土种群的影响，是保护生物学与生态学研究的核心议题。尽管近期外来捕食者对本土猎物种群的影响已受到广泛关注，但引入猎物对本土捕食者种群的影响却较少被深入阐释。外来猎物可通过直接与间接途径影响捕食者的行为与种群动态，但针对多种潜在相互抵消的效应如何共同作用于本土捕食者种群增长的定量评估仍较为匮乏。本研究依托近20年的全分布区监测数据，探究了近期被引入且快速扩散的外来猎物物种福寿螺（Pomacea maculata）对濒危螺鸢（Rostrhamus sociabilis）行为与种群动态的影响。已有研究表明，相较于本土的平扁蜷（Pomacea paludosa），福寿螺体型更大，会导致幼鸢在取食处理时遭遇困难，进而引发能量摄入不足，这提示其存在演化层面的潜在影响（原文语句未完整）。