Does foraging adaptation create the positive complexity-stability relationship in realistic food-web structure?

Area of Science:

• Ecology
• Theoretical Ecology
• Food Web Dynamics

Background:

• The adaptive food-web hypothesis proposes that adaptive foraging stabilizes complex ecosystems, contrasting with traditional negative complexity-stability relationships.
• This hypothesis's validity in natural settings is debated, as niche models, a standard ecological benchmark, do not show this stabilizing effect.
• A key challenge is understanding why niche models fail to support the adaptive food-web hypothesis.

Purpose of the Study:

• To investigate the role of basal species fraction in masking the positive complexity-stability relationship in niche models.
• To determine if adaptive foraging can stabilize food webs within a niche model framework.
• To identify the conditions under which the adaptive food-web hypothesis is robust and applicable.

Main Methods:

• Utilized a niche model, a benchmark for food-web dynamics, to simulate ecosystem complexity.
• Analyzed the influence of increasing connectance on the fraction of basal species.
• Performed model analysis to isolate and eliminate confounding effects of basal species on system stability.

Main Results:

• Increasing connectance in niche models was found to increase the fraction of basal species, leading to system destabilization.
• This destabilizing effect of basal species fraction masked the positive complexity-stability relationship predicted by adaptive foraging.
• When this confounding effect was controlled, niche models demonstrated that populations are more likely to persist in more complex food webs.

Conclusions:

• The adaptive food-web hypothesis is robust and applicable even within realistic niche models.
• The fraction of basal species is a critical factor that can obscure the stabilizing effects of adaptive foraging in complex food webs.
• Future research should focus on testing the adaptive food-web hypothesis under conditions where the influence of basal species is accounted for.