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Article
Vegetation Dynamics and Mesophication in Response to Conifer Encroachment Within an Ultramafic System
Australian Journal of Botany (2015)
  • Jerry Burgess, Johns Hopkins University
  • Katalin Szlavecz, Johns Hopkins University
  • Nishanta Rajakaruna, College of the Atlantic
  • Steven Lev, Towson University
  • Christopher Swan, University of Maryland - Baltimore County
Abstract
The biological, ecological, and evolutionary significance of serpentine habitats has long been recognised. We used an integrated physiochemical dataset combining plot spatial data with temporal data from tree cores to evaluate changes in soils and vegetation. Data suggest that this unique habitat is undergoing a transition, endangering local biodiversity and endemic plant species. The objective of this work was to analyse the vegetation dynamics of a xeric serpentine savanna located in the Mid-Atlantic, USA. We employed vegetation surveys of 32 10 × 15 m quadrats to obtain woody species composition, density, basal area, and developed a spatial physiochemical dataset of substrate geochemistry to independently summarise the data using regression and ordination techniques. This information was interpreted alongside historical, dendrochronologic and soil stable carbon isotopic data to evaluate successional dynamics. Comparisons among geologic, pedologic and vegetation environmental drivers indicated broad correlations across an environmental gradient, corresponding to a grassland to forest transition. The woodland communities appear to be part of a complex soil moisture and chemistry gradient that affects the extent, density, basal area and species composition of these communities. Over the gradient, there is an increase in α diversity, a decrease in the density of xeric and invasive species, and an increase in stem density of more mesic species. Dendrochronology suggests poor recruitment of xeric species and concomitant increase in more mesic species. The data indicated that former C4-dominated grasslands were initially invaded by conifers and are now experiencing mesophication, with growing dominance by AcerNyssa and more mesic Quercus and Fagus species.
Keywords
  • edaphic,
  • plant–soil relations,
  • serpentine,
  • succession
Disciplines
Publication Date
2015
DOI
10.1071/BT14241
Citation Information
Jerry Burgess, Katalin Szlavecz, Nishanta Rajakaruna, Steven Lev, et al.. "Vegetation Dynamics and Mesophication in Response to Conifer Encroachment Within an Ultramafic System" Australian Journal of Botany Vol. 63 Iss. 4 (2015) p. 292 - 307 ISSN: 0067-1926
Available at: http://works.bepress.com/nishanta_rajakaruna/35/