Species Diversity and Abundance in Insular Systems

摘要96-15151岛状系统中舍纳物种的多样性和丰富性这是一项对巴哈马群岛食物网的长期实验和观测研究。食物链中的特定物种可能通过捕食直接影响其他物种的丰度(捕食者减少猎物，相应地，捕食者增加捕食者)，或间接通过其他物种(例如，捕食者可能通过捕食草食动物间接帮助植物)。之前的实验通过操纵较小的捕食者来确定它们的直接和间接影响。拟议中的两个实验操控了更大的捕食者。首先，大型蜥蜴将被引入到有较小蜥蜴的地方。其次，鸟类和较小的蜥蜴将被排除在交叉设计之外。这两种较大的捕食者在它们的影响上应该有根本的不同，特别是对植物：前者吃较小的捕食者，而鸟类也吃较小的捕食者的猎物，特别是草食性昆虫。此外，将监测100多个岛屿上的移民(自然“引入”)和灭绝(自然“迁移”)，以确定其频率和长期影响。

ABSTRACT 96-15151 Schoener Species Diversity and Abundance in Insular Systems This is a long-term experimental and observational study of food webs in islands of the Bahamas. A particular species in a food web may affect other species' abundances directly, via predation (predators reduce prey and, correspondingly, prey increase predators) or indirectly, via other species (e.g. predators may help plants indirectly by eating their herbivores). Previous experiments manipulated smaller predators to determine their direct and indirect effects. The proposed two experiments manipulate larger predators. First, large lizards will be introduced to places having smaller lizards. Second, birds and smaller lizards will be excluded in a crossed design. The two types of larger predators should differ fundamentally in their effects, particularly on plants: the former eat smaller predators, whereas birds also eat prey of the smaller predators, especially herbivorous insects. Additionally, immigrations (natural "introductions") and extinctions (natural "removals") on over 100 islands will be monitored to determine their frequency and long-term effects.