Patterns of herbaceous and woody vegetation recruitment in a recently restored tidal and non-tidal freshwater wetland

Background/Question/Methods

This study examines the natural ecological restoration of a human-disturbed habitat and the recruitment of Taxodium distichum Rich. within the site. We have defined the term “natural ecological restoration” as the re-establishment of an ecosystem exclusive of anthropogenic inputs such as vegetative or hydrologic alterations. The presence of T. distichum was quantitatively assessed as it is a model organism for the regeneration of destroyed forested wetlands due to its ability to survive in permanently or semi-permanently flooded conditions. Objectives for this study were: (1) to show geospatial relations of recruitment patterns among colonizing species, (2) to determine if recruitment of T. distichum occurs, and if so (3) to identify areas viable for natural restoration and restorative planting of T. distichum. The research site was a recently emerged freshwater marsh at Kimages Creek along the tidal James River in the Coastal Plain of Virginia. The creek was dammed for recreational purposes in the 1920’s to form Lake Charles; later drained in the fall of 2006 by a natural breech in the berm. For this study, the former lake basin was divided into three research sections: tidal Kimages Creek, non-tidal Kimages Creek, and an unnamed tributary of Kimages Creek.

Results/Conclusions

Colonizing vegetation accounted for approximately 194,012 m² of the study site. The first and second highest percentage area totals for plant composition were Typha angustifolia L. (46.458%, 90,134 m²) and Leersia oryzoides L. (27.141%, 52,656 m²), respectively. The first and second smallest percentage area totals were an unidentified cutgrass and Microstegium vimineum Trin., respectively. Overall, 146 individuals of T. distichum were mapped. It was found that 75% of the T. distichum individuals were approximately 4 years or less in age. It was also observed that Typha angustifolia L., Murdannia keisak Hassk., and Heteranthera reniformis Ruiz & Pav. were the most dominant species in the tidal portions of the basin.  In the non-tidal Kimages Creek, cutgrasses (an unidentified species and Leersia oryzoides L.) tended to be more dominant. The non-tidal portions of Kimages Creek were populated by native species whereas the tidal portions were populated by invasive species (both exotic and native). A map and a usable GIS environment regarding wetland plant communities within the basin can be used for future studies. The data illustrates a trend of T. distichum recruitment. The greatest number of T. distichum individuals was found in the tributary of Kimages Creek.