Data from: Regime shifts in marine communities: a complex systems perspective on food web dynamics

Species composition and habitats are changing at unprecedented rates in
the world’s oceans, potentially causing entire food webs to shift to
structurally and functionally different regimes. Despite the severity of
these regime shifts, elucidating the precise nature of their underlying
processes has remained difficult. We address this challenge with a new
analytic approach to detect and assess the relative strength of different
driving processes in food webs. Our study draws on complexity theory, and
integrates the network-centric Exponential Random Graph Modeling (ERGM)
framework developed within the social sciences with community ecology. In
contrast to previous research, this approach makes clear assumptions of
direction of causality and accommodates a dynamic perspective on the
emergence of food webs. We apply our approach in analysing food webs of
the Baltic Sea before and after a previously reported regime shift. Our
results show that the dominant food web processes have remained largely
the same, although we detect changes in their magnitudes. The results
indicate that the reported regime shift may not be a system-wide shift,
but instead involve a limited number of species. Our study emphasizes the
importance of community-wide analysis on marine regime shifts and
introduces a novel approach to examine food webs.