Ecological periodic tables for nekton and benthic macrofaunal community usage of estuarine habitats

Background/Question/Methods

The chemical periodic table, the Linnaean system of classification, and the Hertzsprung-Russell diagram are iconic information organizing systems because they are simple, easy to understand, exceptionally useful, and they foster the expansion of scientific understanding and inquiry. Ecological periodic tables are information organizing systems founded on the ecological tenet that the biophysical environment, that is, habitats, structure biotic communities. Their elements are operationally defined habitat types. Their attributes are recurring (periodic) properties of a biotic community. To address the question “Can ecological periodic tables be constructed for nekton and benthic macrofaunal communities in estuarine habitats?,” we conducted replicate, estuary-wide, stratified-by-habitat, quantitative field studies and tested for periodic habitat usage patterns in species composition (Bray–Curtis similarity; ANOSIM) and community structure (species richness, abundance, biomass, and diversity; ANOVA). For nekton, four habitat types (intertidal eelgrass [Zostera marina], burrowing mud shrimp [Upogebia pugentensis], burrowing ghost shrimp [Neotrypaea californiensis], and bare sand) were investigated for periodic patterns of community usage; for benthic macrofauna, those four habitat types and up to five others (intertidal dwarf eelgrass [Zostera japonica], bare mud, oyster, shell, and subtidal) were investigated.

Results/Conclusions

Nekton Bray–Curtis similarity was significantly different across all habitats. Nekton species richness, abundance and biomass were, respectively, on average, 8×, 25×, and 25× greater in eelgrass, 4×, 6×, and 5× greater in burrowing mud shrimp, and 2×, 3×, and 2× greater in burrowing ghost shrimp than in sand habitat. Benthic macrofaunal Bray–Curtis similarity was significantly different across all the habitats except eelgrass and oyster. Thus, eelgrass and oyster habitat are habitat isotopes, from the Greek iso (same) and topos (place), in the sense that they should occupy the same place in a benthic macrofaunal ecological periodic table because their usage of those two habitats is essentially the same. Periodic patterns of differences in habitat usage by benthic macrofauna were observed for the other habitats investigated. We propose the convention that elements (habitats) in ecological periodic tables be arranged in rows reflecting their rank order by measures of community structure. Periodic patterns of habitat usage by biotic communities are probably ubiquitous. Like the aforementioned iconic information organizing systems, ecological periodic tables are simple, easy to understand, exceptionally useful and they foster the expansion of scientific understanding and inquiry.