Dept of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ 85721, USA.
Trends Ecol Evol. 1994 Jun;9(6):214-7. doi: 10.1016/0169-5347(94)90246-1.
Interspecific interactions are traditionally displayed in a grid in which each interaction is placed according to its outcome (positive, negative or neutral) for each partner. However, recent field studies consistently find the costs and benefits that determine net effects to vary greatly in both space and time, inevitably causing outcomes within most interactions to vary as well. Interactions show 'conditionality' when costs and benefits, and thus outcomes, are affected in predictable ways by current ecological conditions. The full range of natural outcomes of a given association may reveal far more about its ecological and evolutionary dynamics than does the average outcome at a given place and time.
种间相互作用传统上以网格形式呈现，其中每个相互作用根据其对每个伙伴的结果（正、负或中性）放置。然而，最近的实地研究一致发现，决定净效应的成本和收益在空间和时间上都有很大差异，不可避免地导致大多数相互作用中的结果也发生变化。当成本和收益（因此结果）以可预测的方式受到当前生态条件的影响时，相互作用就表现出“条件性”。给定关联的自然结果的全部范围可能比给定地点和时间的平均结果更能揭示其生态和进化动态。
