292-1 The Impact of Logistical Sampling Constraints on the Identification of Palaeoecological Signals

Session: Life and Environments Through Time and Space: Multi-Record Approaches to Stratigraphic Paleobiology, Part II

Presenting Author:

Alexander Baxter

Authors:

Baxter, Alexander G.¹, Morley, Nathaniel E. D.², Cleary, Willow H.³, Harrington, Kendra L.⁴, Juurlink, J. Zachary⁵, Trujillo, Juan J.⁶, Tremaine, Galadriel⁷, Leighton, Lindsey R.⁸

(1) University of Alberta, Earth & Atmospheric Sciences, Edmonton, AB, Canada, (2) University of Alberta, Earth & Atmospheric Sciences, Edmonton, AB, Canada, (3) University of Alberta, Earth & Atmospheric Sciences, Edmonton, AB, Canada, (4) University of Alberta, Earth & Atmospheric Sciences, Edmonton, AB, Canada, (5) University of Alberta, Earth & Atmospheric Sciences, Edmonton, AB, Canada, (6) University of Alberta, Campus Saint-Jean, Edmonton, AB, Canada, (7) University of Alberta, Earth & Atmospheric Sciences, Edmonton, AB, Canada, (8) University of Alberta, Earth & Atmospheric Sciences, Edmonton, AB, Canada,

Abstract:

When palaeoecologists consider the scope of a novel project or research question, logistical constraints surrounding specimen acquisition are often a primary limiting factor. Length of field season, resource availability, and access to (or even the existence of) field localities all impose limits on potential sampling efforts. To explore the impact of logistical sampling restrictions, we used an exceptional dataset of 116,896 fossil brachiopods from 255 samples across central Nevada spanning from the beginning of the Early Devonian to the end of the Middle Devonian (J. G. Johnson, 1990; Journal of Paleontology). Specifically, we tested whether palaeoecological signals (as represented in an NMDS ordination plot), and the processes that drive them, may be identified despite simulated reductions in spatiotemporal resolution and scope. We created two different resampling protocols in order to perform these reductions. The first protocol simulated limitations on the absolute number of samples collected by randomly culling samples from the dataset and retesting for the original signal. The second protocol simulated the inability to travel to, and collect from, geographically separated regions by organizing the data into time-bins and then comparing the basin-wide NMDS signal to the signal obtained from a single region within the study area for each bin. The primary palaeoecological signal identified in NMDS ordination plots of the entire dataset (a separation of two data clouds based on temporal interval) was identifiable > 98% of the time with as few as 26 randomly selected samples, and NMDS ordinations of geographically restricted subsamples representing temporal intervals of ≥5 Myr were found to contain signals consistent with those of the entire study area. Thus, it was possible to capture the primary signals corresponding to biodiversity shifts on broad scales with limited sampling power, and without extensively sampling outside of a single geographical region.

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

doi: 10.1130/abs/2025AM-5944

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