Population biology and rarity: on the complexity of density dependence in insect—plant interactions

摘要: The subject of density dependence has been a central obsession population ecologists for at least 60 years (e.g. Nicholson, 1933; Varley, 1947; Lack, 1954; Ricker, Orians, 1962; McLaren, 1971; Antonovics and Levin, 1980; Sinclair, 1989), with good reason. If we could understand how the ‘vital rates’ (the rates reproduction survivorship) change as it grows or shrinks, predict population’s dynamics. We should be able to calculate whether will reach some stable equilibrium value, collapse extinction, even exhibit cyclical chaotic Yet past work on remarkably one-sided. study concerns consequences being (at locally) rare common, yet vast majority research date dealt only half this question. Almost all attention centred behaviour populations high density, they approach surpass carrying capacity their environments, focused processes that prevent species from becoming infinitely abundant. This is, course, an important question, but does not exhaust density-dependent effects. There are many interesting issues studied opposite end spectrum, concerning local extinction.