Biology subjects

Dunne, J. A.

Publications and source records attributed to Dunne, J. A..

3 recordsLinked to original sources

bioRxiv2026

Temporal resolution reshapes dynamics of inferred community structure and extinction selectivity across the Permian-Triassic mass extinction

The Permian-Triassic mass extinction fundamentally restructured ecosystems, yet it remains unresolved whether ecological collapse unfolded gradually or in discrete steps, and how extinction selectivity varied with environmental change. Here, we analyse marine food webs from Meishan (China) at high temporal resolution. We show that trophic structure destabilised prior to peak biodiversity loss, followed by a structural tipping point during the extinction interval when the community became less robust to secondary extinctions. Extinction selectivity shifted substantially across the study interval. During the extinction interval, extinction was concentrated at lower trophic levels, propagating upwards from benthic herbivores to higher-level consumers. Although coarse resolution preserves temporal trends in trophic structure and extinction selectivity, it obscures abrupt transitions, sequential extinction dynamics, and critical shifts in ecological organisation. We demonstrate that temporal resolution governs inference of extinction dynamics, with important implications for reconstructing past ecological crises and interpreting ecosystem responses to rapid environmental change.

paleontology↗

bioRxiv2026

No global collapse of food webs across the Permian-Triassic Mass Extinction

The Permian-Triassic mass extinction (PTME), the Earths most severe biotic crisis associated with extreme environmental perturbations, eliminated >80% of marine species1. However, whether it triggered a globally pervasive top-down collapse of marine food webs, and whether recovery proceeded through bottom-up reassembly, remain unresolved2-4. Here we reconstruct spatially explicit metacommunity food webs from seven regions spanning equatorial to high latitudes to test how extinction dynamics and ecosystem reorganization varied geographically. By integrating estimates of community structure and species interactions, we provide direct inference on trophic disruption across the PTME. Despite catastrophic species loss and flattening of the latitudinal diversity gradient5, trophic collapse was not globally uniform, and higher trophic levels were not globally truncated. Instead, extinction selectivity was spatially heterogenous and tracked environmental severity. Benthic, low-motility herbivores with limited respiratory capacity were disproportionately lost, consistent with intensified warming, deoxygenation and disruption of primary productivity under elevated pCO2. Mid-to high-latitude communities became top-heavy and structurally complex, whereas tropical systems remained bottom-heavy and less robust to secondary extinction. These results demonstrate that trophic disruption and recovery were geographically structured, mediated by environmental forcing, species traits and pre-extinction food-web architecture, with implications for predicting marine ecosystem responses to ongoing climate change.

paleontology↗

bioRxiv2024

A framework for reconstructing ancient food webs using functional trait data

O_LIFood webs provide quantitative insights into the structure and dynamics of ecological communities. Previous work has shown their utility in understanding community responses to modern and ancient perturbations, including anthropogenic change and mass extinctions. However, few ancient food webs have been reconstructed due to difficulties assessing trophic interactions amongst extinct species derived from an incomplete fossil record. C_LIO_LIWe present and assess the Paleo Food web Inference Model (PFIM). PFIM uses functional trait data--predictive of interactions in modern ecosystems and commonly available for fossil organisms--to reconstruct ancient food webs. We test the model by (i) applying it to four modern ecosystems with empirical constrained food webs to directly compare PFIM-constructed networks to their empirical counterparts, (ii) by carefully comparing discrepancies between PFIM-inferred and empirical webs in one of those systems, and (iii) by comparing networks describing feasible trophic interactions ("feasible webs") with networks to which we superimpose characteristic interaction distributions derived from modern theory ("realized webs"). As a proof of concept, we then apply the method to faunal data from two Cambrian fossil deposits to reconstruct ancient trophic systems. C_LIO_LIPFIM-inferred feasible food webs successfully predict [~]70% of trophic interactions across four modern systems. Furthermore, inferred food webs with enforced interaction distributions (i.e., realized webs) accurately predict [~]90% of interactions. Comparisons with a global database of trophic interactions and other food web models, suggest that under sampling of empirical webs accounts for up to 21% of the remaining differences between PFIM and empirical food webs. C_LIO_LIFood webs can be reasonably approximated by inferring trophic interactions based upon life habit traits. This study provides the foundation to use trait-based inference models across the fossil record to examine ancient food webs and community evolution. C_LI

paleontology↗