Yanoviak Stephen P
Department of Zoology, University of Oklahoma, 73019, Norman, OK, USA.
Oecologia. 2001 Jan;126(1):125-133. doi: 10.1007/s004420000493. Epub 2001 Jan 1.
Predation and resource availability influence community structure in many aquatic ecosystems. Predators (odonates) and resources (leaf litter) were manipulated to determine their independent effects on macroorganism species richness, abundance, and composition in water-filled tree holes of Barro Colorado Island, Panama. Interactive effects of these factors were also investigated in artificial tree holes. Large odonates reduced species richness in natural tree holes, but did not significantly reduce macroorganism abundance. The presence of larvae of the mosquito Culex urichii and the ceratopogonid midge Bezzia snowi were negatively associated with the presence of large odonate larvae. In natural tree holes, leaf litter addition and removal respectively increased and decreased richness by c. 1 species relative to controls, and macroorganism abundance was greater in litter addition holes than in litter removal holes. Independent effects of predation showed similar patterns in artificial holes, but there was no predator×resource interaction, partly due to the short duration of the experiment. Predators grew faster when litter was abundant, and indirectly reduced litter degradation rates when resources were scarce in artificial holes. Both resource availability and predation influence species richness in water-filled tree holes, but act at different time scales; richness follows productivity (litter quantity) over a period of weeks, whereas effects of predation may span several months.
捕食和资源可利用性会影响许多水生生态系统的群落结构。对捕食者（蜻蜓目昆虫）和资源（落叶）进行了操控，以确定它们对巴拿马巴罗科罗拉多岛充满水的树洞中大型生物的物种丰富度、丰度和组成的独立影响。还在人工树洞中研究了这些因素的交互作用。大型蜻蜓目昆虫降低了天然树洞中的物种丰富度，但并未显著降低大型生物的丰度。库蚊和雪氏铗蠓的幼虫的存在与大型蜻蜓目昆虫幼虫的存在呈负相关。在天然树洞中，添加落叶和去除落叶相对于对照分别使丰富度增加和减少了约1个物种，并且添加落叶的树洞中的大型生物丰度高于去除落叶的树洞。捕食的独立影响在人工树洞中呈现出类似的模式，但不存在捕食者×资源的交互作用，部分原因是实验持续时间较短。在人工树洞中，当落叶丰富时捕食者生长更快，而当资源稀缺时会间接降低落叶的降解速率。资源可利用性和捕食都会影响充满水的树洞中物种的丰富度，但作用于不同的时间尺度；丰富度在数周的时间内随生产力（落叶数量）变化，而捕食的影响可能会持续数月。
