Multiple environmental changes interact to modify species dynamics and invasion rates

摘要: Multiple aspects of the environment often change at same time, influencing populations directly by modifying their physiology, but also indirectly other interacting species. The impacts each environmental upon population dynamics are usually assumed be independent state environment, despite evidence individual level indicating that combined non-additive. importance indirect effects mediated through community interactions has high uncertainty. We used experimental microcosms to determine whether factors interact affect species and relative direct on dynamics. We factorially manipulated three (temperature, food availability salinity) examined reciprocal invasions competing protist under environment. Experimental observations were parameterize a dynamic model system. Using this novel variance decomposition method, we mechanisms which changes altered invasion rates. The interacted when growth rates, intra- interspecific competition, causing impact depend crucially Indirect in abundance resident competitor its competitive ability main cause driven variation whilst intrinsic rates relatively unimportant. This indicates that, understand ultimately predict responses multiple changes, should consider joint they modify key ecological processes such as competition.