Conserving alpha- and beta-diversity in wood production landscapes

Authors: JONES, GAVIN - Us Forest Service (FS); FROSI, BERRY - Emory University; EVANS, JASON - Stetson University; GOTTLIEB, ISABEL G.W. - University Of Florida; LOX, XINGWEN - Emory University; NUNEZ-REGUEIRO, MAURICIO - University Of Florida; OBER, HOLLY - University Of Florida; PIENAAR, ELIZABETH - University Of Georgia; PILLAY, RAJEEV - University Of Florida; Pisarello, Kathryn; SMITH, LORA - Jones Ecological Resesearch Center; FLETCHER, ROBERT - University Of Florida

Submitted to: Conservation Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/25/2021
Publication Date: 12/2/2021
Citation: Jones, G.M., Frosi, B., Evans, J.M., Gottlieb, I., Lox, X., Nunez-Regueiro, M.M., Ober, H.K., Pienaar, E., Pillay, R., Pisarello, K., Smith, L.L., Fletcher, R.J. 2021. Conserving alpha- and beta-diversity in wood production landscapes. Conservation Biology. https://doi.org/10.1111/cobi.13872.
DOI: https://doi.org/10.1111/cobi.13872

Interpretive Summary: Human-induced land cover changes are increasing as agricultural demands both intensify and evolve. The sustainable energy market, including bioenergy derived from pine plantations, is impacting the agricultural landscape as demands for biofuel production increase. These land cover changes will have presently unknown impacts on ecosystem services, including biodiversity. Here, we empirically examined the potential impact pine plantation management strategies will have on 1) species richness (alpha-diversity) and 2) species composition dependent on pine plantation management strategies (beta-diversity) across four taxa (bats, bees, birds, and reptiles) in the southeastern United States. It should be noted that although landscapes with no bioenergy-type harvests resulted in highest cumulative alpha-diversity, no scenario allowed for the full representation of observed species in the system. Based on data collected within multiple sites and during multiple years, it was found that both alpha- and beta-diversity were reduced under pine plantation management practices characterized by short-rotation and residue removal after clearcuts, while alpha- and beta-diversity increased under the mid-rotation pine thinning scenario. Additionally, the response of beta-diversity to management strategies was more predictable than alpha-diversity across all four taxa. Therefore, we concluded that different species live in the various habitats generated by wood extraction and that beta-diversity may be a better indicator than alpha-diversity in measuring species response to land cover change.

Technical Abstract: International demand for wood and other forest products continues to grow rapidly, and uncertainties remain about how animal communities will respond to intensifying resource extraction associated with woody bioenergy production. We examined changes in alpha- and beta-diversity of four taxonomic groups (bats, bees, birds, reptiles) across a large portion of wood production landscapes in the southeastern United States, a biodiversity hotspot that is one of the principal suppliers of woody biomass globally. We sampled across a spatial gradient of paired forest land-uses that allowed us to evaluate biological community changes resulting from biomass harvests: residue removal following clearcuts, mid-rotation thinning, and reduced stand age from short-rotation practices, respectively. Short-rotation practices and residue removal following clearcuts were associated with reduced alpha-diversity (-14.1 and -13.9 species, respectively) and lower beta-diversity (i.e., Jaccard dissimilarity) between land-use pairs (0.46 and 0.50, respectively), whereas mid-rotation thinning increased alpha- (+3.5 species) and beta-diversity (0.59). We found that over the course of a stand rotation in a single location, biomass harvesting generally led to less biodiversity. Cross-taxa responses to resource extraction were poorly predicted by alpha-diversity: correlations in responses between taxonomic groups were highly variable in direction (-0.2 to 0.4) with large uncertainties. In contrast, beta-diversity patterns were highly consistent and predictable across taxa, where correlations in responses between taxonomic groups were all positive (0.05 to 0.4) with more narrow uncertainties. Beta-diversity may therefore be a more reliable and information-rich indicator than alpha-diversity in understanding animal community response to landscape change. Patterns in betadiversity were primarily driven by turnover instead of simple species loss or gain, indicating that wood extraction is generating habitats that support different biological communities. Our work provides an unprecedented empirical analysis of the effects of alternative energy development on biodiversity and insights into the critical role of betadiversity in biodiversity monitoring.