Which of the following is NOT an attribute of ecological communities?
Community attributes describe collective composition and organization, including species-abundance distributions, food-web structure and stability, and patterns created by coexistence constraints such as limiting similarity. A log-series distribution summarizes how individuals are apportioned among many species, while responses of food webs to disturbance concern community-level organization. Limits to similarity address how competing species partition niches sufficiently to coexist. Local extinction caused by demographic stochasticity is primarily a population-level process: random variation in births and deaths can eliminate a small population even without environmental change. Although such extinctions influence communities over time, the process itself is not conventionally listed as an intrinsic community attribute. Ecological categories are simplified models, yet they remain valuable when their assumptions are stated. The selected description captures the dominant net effect, while real systems may vary with density, habitat, life stage, and environmental conditions. This reasoning connects organismal behavior with broader ecological consequences. A mechanism that changes encounter rates, resource use, or reproductive success can scale up to alter population trajectories and the structure of species interactions.
Ref: Ecology: From Individuals to Ecosystems, Begon et al., 5th Ed., Ch. 8-13