Understory dynamics in North Carolina longleaf pine savannas: Biodiversity, dominance, and biomass

UNCG Author/Contributor (non-UNCG co-authors, if there are any, appear on document)
Sally E. Koerner, Assistant Professor (Creator)
The University of North Carolina at Greensboro (UNCG )
Web Site: http://library.uncg.edu/

Abstract: Questions Restoration of ecosystems is complex, with multiple targets that can work in concert orconflict with each other, such as biodiversity, species dominance and biomass. When properlymanaged, longleaf pine (LLP) savannas are among the most biologically diverse habitats in theworld. However, anthropogenic influences, such as fire suppression, have decimated thisecosystem and its biodiversity, making restoration a priority. Here, we describe the biodiversityand community dynamics seen in the understory layer across xeric LLP savannas in North Carolinaand then answer the following questions: What are the predictors of (1) biodiversity, (2) dominanceand (3) biomass at multiple spatial scales?Location Fifteen observational study sites in North Carolina spanning from the Sandhills to theCoastal Plain.Methods At each of the 15 sites, 25 sampling plots were established where above-groundherbaceous biomass, species presence and abundance, soil characteristics and light availabilitywere measured along with numerous other environmental variables.Results Considerable variation exists across study plots within and across sites, with plant speciesrichness ranging from 1 to 17 per m2. The relative cover of the dominant grass species, Aristidastricta (wiregrass), also varied greatly within and across sites, with a median of ca. 30% relativecover per plot. Wiregrass was a significant predictor of biomass and biodiversity at small scales.With increasing wiregrass abundance, richness decreases, with 25% relative wiregrass coverleading to the highest levels of biodiversity. Likewise, because wiregrass abundance is one of thestronger predictors of above-ground biomass, we also found a unimodal richness–biomassrelationship.Conclusions Our results indicate that at lower ends of the productivity and richness gradients, landmanagers can increase all three restoration targets in the understory at the same time; however, atmore diverse and productive sites, restoration practitioners may need to prioritize one target orfind a balance between all three.

Additional Information

Journal of Vegetation Science, 33
Language: English
Date: 2022
above-ground biomass, Aristida stricta, biodiversity, dominant species, ground layer, productivity, richness, understory restoration, wiregrass

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