Location: Crop Genetics and Breeding ResearchTitle: Seed sourcing for longleaf pine herbaceous understory restoration: little bluestem (Schizachyrium scoparium) and hairy lespedeza (Lespedeza hirta) restoration genetics
|GUSTAFSON, DANNY - The Citadel|
|GUSTAFSON, PARKER - The Citadel|
|GIENCKE, LISA - Jones Ecological Resesearch Center|
|DENHOF, R. CAROL - The Longleaf Alliance|
|KIRKMAN, L. KATHERINE - Jones Ecological Resesearch Center|
Submitted to: Natural Areas Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/17/2018
Publication Date: 10/22/2018
Citation: Gustafson, D.J., Harris-Shultz, K.R., Gustafson, P.E., Giencke, L.M., Denhof, R., Kirkman, L. 2018. Seed sourcing for longleaf pine herbaceous understory restoration: little bluestem (Schizachyrium scoparium) and hairy lespedeza (Lespedeza hirta) restoration genetics. Natural Areas Journal. 38(5):380-392.
Interpretive Summary: The longleaf pine ecosystem once occupied approximately 92 million acres and extended from southeastern Virginia to eastern Texas and from the Florida peninsula to northern portions of Alabama and Georgia. This ecosystem had widely spaced longleaf pine trees of varying ages and an understory that included a rich variety of herbs and grasses dominated by wiregrass and bluestem. Due to fire suppression, logging, conversion of the land to agriculture, and urbanization the longleaf pine ecosystem is now reduced by 96%. The remaining areas harbor nearly 200 types of birds and hundreds of other animal species and mature longleaf pine ecosystems contain some of the most diverse plant communities worldwide. Restoration of the longleaf pine ecosystem has been a priority for many public and private organizations yet ecologically appropriate seed of native understory plants is often difficult to obtain. Many of the seed that is commercially available for restoration projects is sourced from the Midwestern U.S. and thus the success of these seed for the Southeastern U.S. is unknown. In this study, seeds of little bluestem and hairy lespedeza, two co-occurring species of the herbaceous understory, were collected from five seed transfer zones (areas) within the historical range of the longleaf pine ecosystem as well as a commercial seed source originating from outside of this range. The genetic structure and diversity of the collected plants was determined using genetic markers. For both species, plants within the seed transfer zones were genetically different than the commercial source. For both species, plants collected from each zone was genetically distinct except for two zones which suggests these two zones can be merged to form one seed zone. For the remaining seed zones, genetic similarity among plants decreased as geographic distance increased. Our results suggest for restoration projects using little bluestem and hairy lespedeza, that use of seed from the closest available source may be most beneficial.
Technical Abstract: Restoration of the herbaceous understory community of the longleaf pine ecosystem is limited by the availability of appropriate seeds. To understand the relationship of seed transfer zones and genetic composition of two co-occurring species of the herbaceous understory, seeds of little bluestem (Schizachyrium scoparium) and hairy lespedeza (Lespedeza hirta) were collected from five provisional seed transfer zones across the historical range of the longleaf pine ecosystem in the North American Coastal Plain as well as a commercially available seed source originating from outside this range. To determine the genetic structure and diversity of these plants within the seed transfer zones and the commercial source, microsatellite and inter-simple sequence repeats (ISSR) markers were used for little bluestem and hairy lespedeza, respectively. For both species, plants from within the five seed transfer zones were genetically distinct from the commercial source from Kentucky. Little bluestem and hairy lespedeza plants from two provisional seed transfer zones were more genetically similar to each other than they were to other seed zones, which could justify merging these two zones. The genetic relationships among the remaining seed zones, including the commercial source from Kentucky, roughly follow geographic proximity, with genetic similarity decreasing as a function of geographic distance. Most of the genetic variation was partitioned within and less among seed zones, despite documenting significant differences among seed zones. The results of this study support the sub-The Nature Conservancy ecoregion seed transfer zones while acknowledging species-specific differences among seed transfer zones for the longleaf pine ecosystem.