Agricultural land-use history does not reduce woodland understory herb establishment
Agricultural land use is a leading cause of habitat degradation, leaving a legacy of ecological impacts long after agriculture has ceased. Yet the mechanisms for legacy effects, such as altered plant community composition, are not well understood. In particular, whether plant community recovery is limited by an inability of populations to establish within post-agricultural areas, owing to altered environmental conditions within these areas, remains poorly known. We evaluated this hypothesis of post-agricultural establishment limitation through a field experiment within longleaf pine woodlands in South Carolina (USA) and a greenhouse experiment using field-collected soils from these sites. In the field, we sowed seeds of 12 understory plant species associated with remnants (no known history of agriculture) into 27 paired remnant and post-agricultural woodlands. We found that post-agricultural woodlands supported higher establishment, resulting in greater species richness of sown species. These results were context dependent, however, with higher establishment in post-agricultural woodlands only when sites were frequently burned, had less leaf litter, or had less sandy soils. In the greenhouse, we found that agricultural history had no impact on plant growth or survival, suggesting that establishment limitation is unlikely driven by differences in soils associated with agricultural history when environmental conditions are not stressful. Rather, the potential for establishment in post-agricultural habitats can be higher than in remnant habitats, with the strength of this effect determined by fire frequency and soil characteristics.
KeywordsAgricultural legacy Establishment limitation Longleaf pine woodland Fire Soil legacy
We thank Chelsea Blake, John Blake, Katie Biggert, Joey Bukowski, Chris Habeck, Emily Heald, Bridget Johnson, Skylar Johnson, Clay Lovelace, Ed Olson, Emily Reed, Chris Shaw, Zachary Smith, Jeannie Williams, and Kim Wright, for their roles in creating and maintaining this experiment and collecting data. This work was supported by funds provided to the Department of Agriculture, Forest Service, Savannah River, under Interagency Agreement DE-EM0003622 with the Department of Energy, Aiken, SC; JLO was supported by a UW Vilas Associates Fellowship during a portion of this work.
Author contribution statement
LAB, JLO, and NET conceived and designed the experiments. JAL, NET, and CAB performed the experiments. NET analyzed the data. All the authors wrote the manuscript.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
- Bartoń K (2016) MuMIn: multi-model inference. R package version 1.15.6. https://CRAN.R-project.org/package=MuMIn. Accessed 8 Mar 2018
- Clark CJ, Poulsen JR, Levey DJ, Osenberg CW (2007) Are plant populations seed limited? A critique and meta-analysis of seed addition experiments. Am Nat 170:128–142Google Scholar
- de la Peña E, Baeten L, Steel H, Viaene N, De Sutter N, De Schrijver A, Verheyen K (2016) Beyond plant-soil feedbacks: mechanisms driving plant community shifts due to land-use legacies in post-agricultural forests. Funct Ecol 30:1073–1085. https://doi.org/10.1111/1365-2435.12672 CrossRefGoogle Scholar
- Jaeger B (2017) r2glmm: computes R squared for mixed (multilevel) models. R package version 0.1.2. https://CRAN.R-project.org/package=r2glmm Accessed 8 Mar 2018.
- Kilgo JC, Blake JI (2005) Ecology and management of a forested landscape: fifty years on the Savannah River Site. Island Press, WashingtonGoogle Scholar
- Suding KN (2011) Toward an era of restoration in ecology: successes, failures, and opportunities ahead. Annu Rev Ecol Evol Syst 42:465–487. https://doi.org/10.1146/annurev-ecolsys-102710-145115 CrossRefGoogle Scholar