The response of ammophila breviligulata and spartina patens (poaceae) to graxing by feral horses on a dynamic mid-atlantic barrier island
Seliskar DM. 2003. The response of ammophila breviligulata and spartina patens (poaceae) to graxing by feral horses on a dynamic mid-atlantic barrier island. American Journal of Botany. 90(7):1038-1044
Ammophila breviliglliata, American beachgrass, and Spartina patens, salt meadow hay, have been grazed by feral horses on the dunes of Assateague Island for hundreds of years; however, because of a significant increase in the horse population since the I960s, overgrazing and dune erosion have become problems. Grazing was assessed on foredunes of four different morphologies along a 2 Jkm stretch of the Maryland portion of the island using 17 exclosure plot pairs. In addition to decreased cover and biomass of the two species, plant structure was significantly affected by grazing. Leaf length and width, stem diameter, and stem density of A. breviliglliata and stem diameter of S. patens were reduced in the grazed plots. Especially sensitive to grazing were reproductive characteristics. Percentage of plants in flower, height of flowering stems, and inflorescence length were all significantly reduced by grazing (nongrazedindividuals measured). Species composition was not affected by horse accessibility.
- Type
- Journal Article
- Authors
- Seliskar, Denise
- Units
- ASIS
- Keywords
- AMMOPHlLA BREVILIGULATA, Assateague Island, Barrier Island, feral horses, Spartina patens