HABITAT SELECTION UNDER PREDATION HAZARD - TEST OF A MODEL WITH FORAGING MINNOWS
HABITAT SELECTION UNDER PREDATION HAZARD - TEST OF A MODEL WITH FORAGING MINNOWS
复制标题
DOI：
10.2307/1939877
复制
发表时间：
1987-12-01
期刊：
影响因子：
4.8
通讯作者：
FRASER, DF
中科院分区：
文献类型：
--
作者：
GILLIAM, JF;FRASER, DF
动物通常会选择在觅食回报和死亡风险方面都不同的栖息地。然而，没有实验研究试图预测资源的增加水平，或死亡率的降低，这将导致觅食者从一个更安全的觅食区域转移到一个更危险（但更丰富）的觅食区域。在这里，我们提出并测试一个模型，指定觅食区（“栖息地”）的选择，将最大限度地减少总死亡率的风险，同时允许收集一些任意的净能量增益。我们测试了该模型与少年溪chubs（Semotilus atromaculatus）在实验场流中，觅食者可以利用无食物的避难所，并选择两个觅食区，不同的实验操纵的资源密度（Tubifex spp.）。沉积物中的蠕虫）和死亡风险（成年溪中的鱼）。对于测试的情况，模型指定了一个简单的规则：“使用避难所加上死亡率（μ）比率最低的地点。总觅食率（f），”即，“最小化μ/ f”。独立的死亡率危险（作为捕食者密度的函数）和总觅食率（作为资源密度的函数）的测量使我们能够预测的资源水平在更危险的觅食网站，应该引起从更安全的转移到更危险的网站。在随后的选择实验中，胖子的偏好与理论预测吻合得很好。“最小化μ/ f”规则（每单位能量的死亡数），也许是经过修改的形式，提供了一个简单的替代“最大化f”（每单位时间的能量）标准，适用于长期率最大化时，捕食危险没有不同的选择。
Animals commonly choose among habitats that differ both in foraging return and mortality hazard. However, no experimental study has attempted to predict the level of increase in resources, or the decrease in mortality hazard, which will induce a forager to shift from a safer to a more hazardous (but richer) foraging area. Here we present and test a model that specifies the choice of foraging areas ("habitats") that would minimize total mortality risk while allowing collection of some arbitrary net energy gain. We tested the model with juvenile creek chubs (Semotilus atromaculatus) in an experimental field stream in which the foragers could utilize a foodless refuge and choose between two foraging areas that differed in experimentally manipulated resource densities (Tubifex spp. worms in sediments) and mortality hazard (adult creek chubs). For the case tested, the model specified a simple rule: "use the refuge plus the site with the lowest ratio of mortality rate (.mu.) to gross foraging rate (f)," i.e., "minimize .mu./f". Independent prior measurements of mortality hazard (as a function of predator density) and gross foraging rate (as a function of resource density) allowed us to predict the resource level in the more hazardous foraging site that should induce a shift from the safer to the more hazardous site. The chubs'' preferences in subsequent choice experiments agreed well with the theoretical predictions. The "minimize .mu./f" rule (deaths per unit energy), perhaps in modified form, provides a simple alternative to the "mazimize f" (energy per unit time) criterion that applies to long-term rate maximization when predation hazard does not differ among choices.