Effects of small-scale habitat fragmentation on predator–prey interactions in a temperate sea grass system
Effects of small-scale habitat fragmentation on predator–prey interactions in a temperate sea grass system
复制标题
小规模栖息地破碎化对温带海草系统捕食者-猎物相互作用的影响
DOI：
--
复制
发表时间：
2013
期刊：
影响因子：
--
通讯作者：
A. Persson
中科院分区：
文献类型：
--
作者：
P. Ljungberg;Thomas B. Hasper;P. A. Nilsson;A. Persson
在过去的几十年里，碎片化已成为生态研究中的一个重要问题。栖息地破碎化在从斑块到景观的几个量级的空间尺度上进行。我们关注与动物觅食决策相关的小规模碎片化效应，最终可能产生分布模式。在受控实验环境中，我们测试了人工海草的小规模破碎对幼鳕鱼（Gadus morhua）摄食行为的影响。此外，我们还研究了碎片化对幼年鳕鱼主要猎物资源之一草虾（Palaemon elegans）分布的影响，以及鳕鱼提供的三个风险级别（无鳕鱼、鳕鱼化学线索和积极觅食鳕鱼）。在破碎的景观中，鳕鱼在海草中停留的时间较短，但虾的总消耗量并未受到影响。虾在分段处理与主动捕食相结合的情况下更大程度地利用植被。我们建议虾根据鳕鱼栖息地特定的觅食能力在沙地和植被栖息地之间进行选择，以最大限度地减少捕食风险，而鳕鱼的目标是最大限度地提高猎物依赖性的觅食率，从而在捕食者和猎物之间产生栖息地选择博弈。此外，草虾的聚集行为仅在积极捕食的处理中被发现。因此，我们认为聚集和植被利用都是虾采用的反捕食者防御策略。因此，我们强调在评估栖息地破碎化对沿海环境营养过程的影响时考虑小规模行为机制的重要性。
During the last decades, fragmentation has become an important issue in ecological research. Habitat fragmentation operates on spatial scales ranging over several magnitudes from patches to landscapes. We focus on small-scale fragmentation effects relevant to animal foraging decision making that could ultimately generate distribution patterns. In a controlled experimental environment, we tested small-scale fragmentation effects in artificial sea grass on the feeding behaviour of juvenile cod (Gadus morhua). Moreover, we examined the influence of fragmentation on the distribution of one of the juvenile cod’s main prey resources, the grass shrimp (Palaemon elegans), in association with three levels of risk provided by cod (no cod, cod chemical cues and actively foraging cod). Time spent by cod within sea grass was lower in fragmented landscapes, but total shrimp consumption was not affected. Shrimp utilised vegetation to a greater extent in fragmented treatments in combination with active predation. We suggest that shrimp choose between sand and vegetation habitats to minimize risk of predation according to cod habitat-specific foraging capacities, while cod aim to maximize prey-dependent foraging rates, generating a habitat-choice game between predator and prey. Moreover, aggregating behaviour in grass shrimp was only found in treatments with active predation. Hence, we argue that both aggregation and vegetation use are anti-predator defence strategies applied by shrimp. We therefore stress the importance of considering small-scale behavioural mechanisms when evaluating consequences from habitat fragmentation on trophic processes in coastal environments.