2 research outputs found
Immanent conditions determine imminent collapses: nutrient regimes define the resilience of macroalgal communities
Este artĂculo contiene 9 páginas, 5 figuras.Predicting where state-changing thresholds lie can be inherently complex in
ecosystems characterized by nonlinear dynamics. Unpacking the mechanisms
underlying these transitions can help considerably reduce this unpredictability.
We used empirical observations, field and laboratory experiments, and
mathematical models to examine how differences in nutrient regimes mediate
the capacity of macrophyte communities to sustain sea urchin grazing. In relatively
nutrient-rich conditions, macrophyte systems were more resilient to
grazing, shifting to barrens beyond 1 800 g m22 (urchin biomass), more than
twice the threshold of nutrient-poor conditions. The mechanisms driving
these differences are linked to how nutrients mediate urchin foraging and
algal growth: controlled experiments showed that low-nutrient regimes trigger
compensatory feeding and reduce plant growth, mechanisms supported by
our consumer–resource model. These mechanisms act together to halve
macrophyte community resilience. Our study demonstrates that by mediating
the underlying drivers, inherent conditions can strongly influence the buffer
capacity of nonlinear systems.The Spanish Ministry of Science and Innovation funded
this research (projects CMT2010-22273-C02-01-02 and CMT2013-
48027-C03-R) and supported J.B. (scholarship BES-2011-043630) and
D.A. (Ramon y Cajal fellowship). The Spanish National Research
Council supported R.A.’s visitorship (CSIC-201330E062).Peer reviewe