CORREDORAS: Stability and resilience of plant communities on long-term scales: assessing co-occurrence ecological networks from palaeoenvironmental records.
One of the most pressing questions for modern society is how to tackle the multifaceted problem of global change, where human actions are provoking cascading, possibly irreversible, impacts in several domains of the Earth systems. In parallel, one of ecology’s major endeavours is to understand what the mechanisms supporting the apparent stability of natural systems are. Our society needs that answer as an urgent imperative to understand how ecosystems will react to current global change, from regional to global spatio-temporal scales. In particular, research on ecosystem stability is progressively focusing on how to measure it as well as on how to explain species coexistence in ecological communities. Ecology needs to identify and understand the mechanisms driving community assembly, and the drivers underlying ecological stability and coexistence. Ecological network research has emerged as a paramount tool in ecology to address those goals as it has proven extremely helpful to define how ecosystems function and has been translated to the services that ecosystems may provide.While theory on how and why ecological interactions vary in space and time is progressively growing in maturity there is comparatively less empirical evidence for that variation in time. And this variability across time is even more acute in longer temporal scales. Temporal dynamics, however, is one of the major axes to assess community stability on global change research, as many stability properties operate differently across temporal scales. Any serious to produce useful recommendations on managing endangered ecosystems implies tracing baseline conditions of ecosystem complexity prior to the impacts of current global change, in long-term, transient dynamics-based scenarios. CORREDORAS will pioneer the use of the palaeoecological record to measure ecological network properties and their changes under different disturbance regimes over centennial to millennial time scales in continuous time series. Therefore, our proposal will foster critical insights in ecological knowledge by exploring ecological network stability over time. In CORREDORAS we will focus on the entire set of significant taxa co-occurrence associations in different time periods for the last 11 000 years (11ka BP, the Holocene), where disturbances can be accurately quantified and early human impact can be clearly traced. Our starting hypothesis is that co-occurrence ecological networks will reveal major structural changes that are coeval with perturbations, natural and human-made, and with climate changes that occurred during the last 11000 years in the central Pyrenees, resulting in stability changes. In this regard, CORREDORAS truly is at the frontier of knowledge as we pose a pioneering hypothesis in an unexplored domain. We will use innovative analytical methods to test it including:1) Molecular techniques to infer as complete as possible past community compositions by using sedimentary ancient DNA -sedaDNA-, 2) Biomarker techniques to reconstruct past hydrological variability, and 3) Quantitative techniques rarely used in long-term studies, such as those for measuring variability in co-occurrence networks or stability in ecological systems.