Gotceitas Vytenis, Colgan Patrick
Department of Biology, Queen's University, K7L 3N6, Kingston, Ontario, Canada.
Oecologia. 1989 Aug;80(2):158-166. doi: 10.1007/BF00380145.
Numerous studies have demonstrated a negative relationship between increasing habitat complexity and predator foraging success. Results from many of these studies suggest a non-linear relationship, and it has been hypothesised that some "threshold level" of complexity is required before foraging success is reduced significantly. We examined this hypothesis using largemouth bass (Micropterus salmoides) foraging on juvenile bluegill sunfish (Lepomis macrochirus) in various densities of artificial vegetation. Largemouth foraging success differed significantly among the densities of vegetation tested. Regression analysis revealed a non-linear relationship between increasing plant stem density and predator foraging success. Logistic analysis demonstrated a significant fit of our data to a logistic model, from which was calculated the threshold level of plant stem desity necessary to reduce predator foraging success. Studies with various prey species have shown selection by prey for more complex habitats as a refuge from predation. In this stydy, we also examined the effects of increasing habitat complexity (i.e. plant stem density) on choice of habitat by juvenile bluegills while avoiding predation. Plant stem density significantly effected choice of habitat as a refuge. The relationship between increasing habitat complexity and prey choice of habitat was found to be positive and non-linear. As with predator foraging success, logistic analysis demonstrated a significant fit of our data to a logistic model. Using this model we calculated the "threshold" level of habitat complexity required before prey select a habitat as a refuge. This density of vegetation proved to be considerably higher than that necessary to significantly reduce predator foraging success, indicating that bluegill select habitats safe from predation.Implications of these results and various factors which may affect the relationships described are discussed.
众多研究表明，栖息地复杂性增加与捕食者觅食成功率之间存在负相关关系。许多此类研究的结果表明存在非线性关系，并且据推测，在觅食成功率显著降低之前，需要一定的复杂性“阈值水平”。我们以大口黑鲈（Micropterus salmoides）捕食不同密度人工植被中的蓝鳃太阳鱼幼鱼（Lepomis macrochirus）为研究对象，检验了这一假设。在测试的不同植被密度下，大口黑鲈的觅食成功率存在显著差异。回归分析显示，植物茎密度增加与捕食者觅食成功率之间存在非线性关系。逻辑分析表明我们的数据与逻辑模型拟合良好，据此计算出降低捕食者觅食成功率所需的植物茎密度阈值水平。对各种猎物物种的研究表明，猎物会选择更复杂的栖息地作为躲避捕食的场所。在本研究中，我们还研究了栖息地复杂性增加（即植物茎密度）对蓝鳃太阳鱼幼鱼在躲避捕食时栖息地选择的影响。植物茎密度显著影响作为避难所的栖息地选择。发现栖息地复杂性增加与猎物栖息地选择之间的关系是正相关且非线性的。与捕食者觅食成功率一样，逻辑分析表明我们的数据与逻辑模型拟合良好。利用该模型，我们计算出猎物选择栖息地作为避难所之前所需的栖息地复杂性“阈值”水平。事实证明，这种植被密度远高于显著降低捕食者觅食成功率所需的密度，这表明蓝鳃太阳鱼会选择免受捕食的安全栖息地。本文讨论了这些结果的意义以及可能影响所述关系的各种因素。
