98-14 CHALLENGES AND LIMITATIONS IN THE ASSESSMENT OF PALEOCOMMUNITY AND FOOD WEB ROBUSTNESS

Session: Linking Biodiversity Loss to Environmental Stressors Through Integrated Approaches

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Abstract:

Ecological robustness is the resistance and resilience of an ecological system to disturbance, where disturbance is any change of the state of the system that is not caused by pre-existing relationships among components within the system. Robustness is of primary concern to paleontologists as a key to understanding how communities and ecosystems have responded to perturbations in the past, e.g. evolutionary innovations, biotic interchanges, disruptions to biogeochemical cycles, climate change, and even those of extraterrestrial origin. Ideally, measuring robustness requires observations on ecological timescales that lie mostly below the resolution of the geological record. Consequently, an increasing number of models are being developed to permit the analysis of paleoecological robustness. However, whereas the reconstruction of paleoecological systems, notably paleo-food webs, has received considerable conceptual and methodological attention, the measurement of robustness, often equated to stability, has proceeded at a similar pace but without sufficient conceptual consideration. 

Here, we will address concepts essential to modeling paleoecological robustness, including: the necessity of including uncertainty and variance during system reconstruction; how perturbations are modeled; and recognition that ecological networks are not static structures, but instead are representations of dynamic systems with hierarchical organization, feedbacks, nonlinear relationships, and emergent properties. Several paleoecological examples will be used, including Panthalassic Permian-Triassic marine communities. The SimEcosys model will be introduced to demonstrate the necessity of incorporating those features, and show that several frequently used measures and network models, 1) chronically overestimate the relevance of common network metrics, 2) underestimate measures of resistance to secondary extinction, and 3) do not measure resilience, thereby misrepresenting robustness. SimEcosys also highlights the significant informational challenges to overcoming these limitations.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-8446

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