The Adaptive Capacity of Aquatic Food Webs

Aquatic food webs are size-structured with organisms eating across a range of size. As such they are webs with extremely generalized feeding strategies. The scale of movement of aquatic organisms also generally increases with size/trophic position, suggesting that spatial coupling of these webs often increases, on average, with increasing trophic level. These webs thus tend to have relatively distinct pathways that are increasingly coupled by mobile generalist foragers as one goes up in trophic position.  Here, we argue that this food web architecture makes for a complex ecosystem that is inherently “flexible” or “adaptive” in that lower level changes are mediated by adaptive responses of higher level species. We argue that empirical, theoretical and applied research needs to embrace this inherently flexible architecture.  Towards this goal, we review and synthesize empirical patterns in aquatic food web structure and argue that recent work has begun to suggest that aquatic food webs often change “consistently” with changing environmental conditions. We then show empirical examples of how understanding the mechanisms that drive this flexible architecture allow us insights into how human-driven impacts, like climate change and fisheries influence food web structure and function.