META-ANALYSIS OF FIELD-BASED FOSSIL COLLECTION METHODS

Different methods of fossil collection (e.g., point counting from slabs, bulk sediment collection) require different levels of effort and may yield different results. Here, we conduct a meta-analysis to determine what factors influence choice of collection method. We examined articles from Palaios, Paleobiology (Pb), and Palaeogeography, Palaeoecology, Palaeoclimatology (P3). In Palaios and Pb, we examined research articles in all volumes dating since 2014. For P3, we covered only paleontology research articles from all 2018 volumes, to obtain data from approximately the same number of articles from each journal.

We focused on articles that 1) used aquatic macroinvertebrates (i.e., not terrestrial, vertebrate, plant, microbe, or microfossils); and 2) were based on fossil material (i.e., not death assemblages, living organisms, or simulations) that 3) was field-collected by the authors for the study at hand (i.e., not museum collections, databases, or literature). The topics were categorized as community paleoecology, biotic interactions, taphonomy/preservation, and “other” topics. Fossil collection method was categorized as “pickup” (hand-picked from ground or outcrop surface), slab/section (methodically counted on hard surfaces or stratigraphic sections), or bulk sediment (from volumes of disaggregated sediment).

We tabulated 703 articles, 93 of which used field-collected, fossil aquatic macroinvertebrates. Slab/section was the most common method (33%), followed by pickup (25%), then bulk sediment (23%). Some articles used more than one method. In 30% of articles, the method was not clearly described. When these “uncertain” articles were assigned a method (from context clues), the distribution changed: pickup 43%, slab/section 47%, bulk 25%.

By topic, 50% of community paleoecology papers used slab/section, followed by pickup (36%) and bulk (32%). Taphonomy/preservation was similar, with 52% slab/section, 36% pickup, but fewer bulk (24%). In biotic interactions, 50% used pickup, 36% bulk, and only 14% slab/section. “Other” papers used more slab/section (56%) and pickup (50%), with only 16% bulk.