Ecosystem stability under environment change

Abstract

Changing climatic conditions is one of the biggest challenges to species persistence and biodiversity maintenance. Numerous biodiversity hotspots are expected to fear unprecedented rises in temperatures in the near future. There is now ample evidence that interaction between large taxa of species is sensitive to temperature. Concerns about rising temperatures have spurred a series of experimental and theoretical investigations to elucidate how warming a ects species abundance and performance. Nonetheless, the impact of climate warming on ecological interactions that can ripple from a minuscule level to vast-scale implications needs more exploration. Climate warming is also manifested as variability in thermal conditions across space and time. Furthermore, the rate at which our planet is heating up is a crucial determinant of ecosystem functioning and stability. In this thesis, we made an attempt to bridge the gap between climate theory, in situ, climate warming, and ecosystem functioning. In this direction, a temperature-dependent consumer-resource model has emerged as one of the vital elements of investigation. The model is characterised by the thermal dependence of species' physiological and behavioural traits, classi ed as rate-controlled and regulatory processes. Relying on a similar framework, we contribute to a comprehensive understanding of how increasing complexity, in terms of species richness and connectance determines the impact of warming on the stability and persistence of species. Further, we study heterogeneity in thermal conditions across space as a mechanism for species to relocate themselves to a feasible habitat, particularly, thermal refugia. Since refugia are proclaimed as key to species survival during outrageous climatic conditions, policymakers emphasise the restoration of such habitats. However, the utility of such retreating habitats in the era of currently changing warming scenarios is still lacking.We map reported climate warming projections: typical seasonal uctuations, warmer-than-average winters, hotter-than-average summers, and periods of sudden heat waves onto a consumer-resource interaction capable to relocate to a thermal refugium.We nd that refugia may not always be crucial to bu er the impact of warming on species persistence. We investigate the occurrence of sudden transitions in a consumer-resource system due to rapid warming.We highlight ecological mechanisms backed up with analytical calculations that lead to rate-induced transitions, and determine the critical rates of warming that can result in abrupt changes in the state of an ecological system. Altogether, our outcomes feature that forestalling or, at the base, obstructing the passing of transition thresholds for most ecosystems requires decreasing the rate at which the current temperature is evolving. Finally, we evaluate the e ect of changing environmental conditions, particularly climate reddening, upon the predictability of sudden transitions in ecosystems.We examine how the temporally correlated environmental uctuations and data sampling impact the early warning signals (EWSs) ability to forewarn both catastrophic and non-catastrophic transitions.