Using predator-prey theory to predict outcomes of broad-scale experiments to reduce apparent competition

Apparent competition is an important process influencing many ecological communities. We used predator-prey theory to predict outcomes of ecosystem experiments aimed at mitigating apparent competition by reducing primary prey. Simulations predicted declines in secondary prey following reductions in primary prey because predators consumed more secondary prey until predator numbers responded to reduced prey densities. Losses were exacerbated by a higher carrying capacity of primary prey and a longer lag time of the predator’s numerical response, but a gradual reduction in primary prey was less detrimental to the secondary prey. We compared predictions against two field experiments where endangered woodland caribou (Rangifer tarandus caribou) were victims of apparent competition. First, when deer (Odocoileus sp.) declined suddenly following a severe winter, cougar (Puma concolor) declined with a 1–2-year lag, yet in the interim more caribou were killed by cougars, and caribou populations d...表观竞争（apparent competition）是影响众多生态群落的关键过程。本研究借助捕食者-猎物理论，对旨在通过削减基础猎物以缓解表观竞争的生态系统实验结果进行预测。模拟结果显示，削减基础猎物后次级猎物种群数量会出现下降——这是由于捕食者在种群数量响应猎物密度降低之前，会更多地捕食次级猎物。基础猎物的环境容纳量越高、捕食者的数值响应时滞越长，次级猎物的种群损失就越严重；而逐步削减基础猎物则对次级猎物的负面影响更小。我们将上述预测结果与两项野外实验数据进行对比，这两项实验中的濒危林地驯鹿（Rangifer tarandus caribou）均为表观竞争的受害者。第一项实验中，当鹿属（Odocoileus sp.）种群在严冬过后突然下降时，美洲狮（Puma concolor）种群会经历1~2年的时滞后才出现衰减，但在此期间美洲狮捕食的驯鹿数量增多，驯鹿种群……