Abstract Detail

Ecology

McCartha, Grace [1], Sims, Caity [2], Kosnik, Brendan [3], Mathew, Jones [4], Abbott, J. Richard [5], Benton, Ben [6], Mangan, Scott [1], Marsico, Travis D. [7].

Plant community patterns and a flora of six Lower Mississippi River islands.

The Lower Mississippi River (LMR) contains unique islands that are isolated from the mainland for all or most of the year. These islands experience intense flood regimes that result in a constant supply of organic materials from upstream, such as sediment and seeds. Moreover, the islands are some of the last remaining floodplain habitats in the Delta region, and surveying their botanical biodiversity is the first step to learning more about plant community structure and ecosystem function in the Mississippi River. From June 2020 through December 2021, we conducted a flora of six LMR islands from Helena-West Helena, Arkansas, to south of Greenville, Mississippi. More than 2,000 plant specimens were collected for a total of 492 species across all six islands. We found 13 species that are putative state records (never before recorded in the state) in Arkansas and three in Mississippi. The six islands span four counties and of the three Arkansas counties, approximately 106 species were found that are county records. From mid-July to late-August 2021, we surveyed plant community composition in 59 100-m2 plots on these six islands following Carolina Vegetation Survey protocol. These plots were established across a range of elevations and habitat types (e.g., sand dunes, swamps, mesic forests) and 276 species were recorded in the plots with species richness ranging from 3 to 80 species per plot. Woody species with the highest percent cover were Celtis laevigata, Forestiera acuminata, and Nekemias arborea, whereas high cover herbaceous species included Cynodon dactylon, Ipomoea lacunosa, and Triplasis purpurea. How abiotic factors (elevation, soil, proximity to tributary confluences, island size, island age, latitude) relate to plant communities on LMR islands will be discussed.

1 - Arkansas State University, Biological Sciences, PO Box 599, State University, AR, 72467, United States
2 - 1515 Aggie Rd, Apt C15, Jonesboro, AR, 72401, United States
3 - 1515 Aggie Rd, Apt C4, Jonesboro, AR, 72401, United States
4 - Arkansas State University, Biological Sciences, PO Box 599, State University, AR, 72467, USA
5 - University of Arkansas at Monticello, Biology, P.O. Box 3480, Monticello, AR, 71656, USA
6 - Arkansas State University, 12 Sethstone Dr, Greenbrier, AR, 72058, United States
7 - Arkansas State University, Department Of Biological Sciences, PO Box 599, State University, AR, 72467, United States

Keywords:
flooding
Biodiversity
Mississippi River
Community composition
flora.

Presentation Type: Oral Paper
Number: EC03002
Abstract ID:468
Candidate for Awards:Ecological Section Best Graduate Student Paper