176-13 Fossil Samples Archive Invertebrate Functional Diversity in Marine Ecosystems: An Empirical Test from Coastal North Carolina

Session: Laws of the Grave: Advances in Taphonomy Across the Paleontologic Record

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Abstract:

The fossil record of functional diversity is increasingly used to study ecosystem evolution, extinction recovery, and factors affecting long-term trends in biodiversity. In addition, the fossil record can provide a historical framework for conservation and restoration and insights into the natural range of functional variability of ecosystems. If fossils yield reasonable estimates of functional diversity, paleontological data could provide information on ecological attributes and trophic structure in past ecosystems allowing for temporally scalable assessments of ecological and evolutionary processes. 

To assess how well fossils preserve functional diversity across multiple types of marine invertebrates with varying preservation potential, we compared the live benthos (135 species from 6 phyla) with sympatric skeletal accumulations (150 species) and the predicted fossil record (112 species) for 51 coastal sites in North Carolina (USA). We found that functional fidelity was high between the live, dead, and fossil assemblages, and nearly all trophic groups were represented in similar proportions in death assemblages and the fossil record. High functional fidelity was also supported by congruence in quantitative functional diversity indices (e.g., functional richness, redundancy, over-redundancy, and vulnerability), overlap in multidimensional functional space, and species distributions among functional groups (rho > 0.85, p << 0.001). Within habitats, functional diversity was somewhat elevated in the DA and FA. While in the entire study region, the DA only had 16 more species than the LA, that disparity increased to as much as 46 in back-barrier, 30 in offshore, and 29 nearshore settings. However, functional diversity nearshore and offshore was very similar, suggesting that functional diversity is less sensitive to water depth and distance from the shoreline than taxon based diversity measures.

Although the generalizability of a single case study should be viewed cautiously, a literature review revealed that the faunal assemblages in this study system are comparable to those documented in other regions and habitat types. Thus, these results are likely applicable to many other types of benthic assemblages. The high functional fidelity reported here suggests that, despite differential preservation and time-averaging, functional estimates based on fossils may allow for historical assessments of ecological and evolutionary processes, including short-term community responses to human impacts as well as long-term macroevolutionary dynamics of marine ecosystems.

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

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