Setting Recovery Targets for Southeast Ecosystems
Sustainable use of military land and water resources is essential to the Department of Defense’s (DoD) continuing ability to train and test military personnel and equipment while meeting its stewardship responsibilities. In 2007, SERDP and the DoD Legacy Resource Management Program sponsored a Workshop on Southeast Region Threatened, Endangered, and At-Risk Species. As a result of this workshop, SERDP issued a Statement of Need for Fiscal Year 2009 that focused on improving our understanding of how historical land use in the Southeast United States had altered ecosystems, how to determine appropriate reference conditions (or recovery targets) for upland and aquatics systems, and how to develop frameworks for assessing the status of extant ecosystems on DoD lands and waters. Years of prior agriculture, commercial forestry, and other land uses and the introductions of non-native invasive species (NIS) had altered these ecosystems to the point they could not be restored to pre-settlement conditions (even if that was desired). In the midst of listed species recovery requirements and a management objective to manage at-risk species so as to preclude future listings, a lack of appropriate target conditions for managing the ecosystems on which these species depended created significant challenges for DoD resource managers to manage these dynamic ecosystems to support both mission and stewardship needs.
As a result, SERDP funded three research projects in 2009 to develop ecological reference models and assessment frameworks for ecological recovery in the southeastern United States. These research projects in combination considered the various constraints on the region, such as land use, regional climate shifts, presence of NIS, and extirpations of native species. Key overall findings from the three projects highlighted below are that although in many instances ecosystems on DoD lands have been altered, they are in reasonable condition overall relative to their surroundings, appropriate use of prescribed fire has aided recovery, and in many cases the extant ecosystems have achievable recovery targets where they have deviated from appropriate reference conditions. The understanding generated by the three projects should assist managers in better understanding realizable and meaningful management endpoints that support ecosystem recovery.
Programs designed to promote the recovery of degraded ecosystems require well defined indicators to clearly show the process of recovery and approach to a desired end state. These end states are embodied in reference models that specify ecosystem characteristics under relatively undisturbed conditions. Led by Dr. Michael Paller of the Savannah River National Laboratory under SERDP project RC-1694, the project team developed reference models for blackwater streams on the southeastern coastal plain. The project team sampled the least disturbed streams remaining in the region, with a focus on fish and macroinvertebrate communities as well as on stream habitat conditions. The models provided the basis for assessment frameworks based on key biological and hydrogeological characteristics that can be used to monitor the ecological health of streams in the regions and assess their progress towards recovery.
Under SERDP project RC-1695, Dr. John Orrock from the University of Wisconsin led a team that developed a set of guidelines to assist recovery of understory plant communities in longleaf pine (Pinus palustris) forests of the southeastern United States. These ecosystems support some of the most diverse plant communities in the world, but are widely degraded by factors such as past agricultural land use, reduced fire frequency, and non-ecologically based timber management. To guide recovery this research team combined large-scale surveys of intact and degraded longleaf pine forests with field experiments on DoD and Department of Energy sites in Georgia, North Carolina, and South Carolina. This approach enabled the team to quantify the impacts of various degrading factors, develop a model to guide recovery decision-making, and test the efficacy of particular management techniques for recovery of these communities across the Southeast.
Measuring success of recovery of ecosystems in response to management requires identification of target benchmark conditions. Too often such targets are themselves rare on the landscape and are seen as a static benchmark for recovery. SERDP project RC-1696 was led by Dr. Bob Mitchell from the Joseph W. Jones Ecological Research Center (JWJERC) and then by Dr. Kay Kirkman from JWJERC and Mr. J. Kevin Hiers from Sewanee: The University of the South after the passing of Dr. Mitchell. The project team presents a new conceptualization of measuring success in ecosystem management and recovery based on the temporal and spatial dynamics of reference conditions to document a fuller understanding of the range of variation that defines success. This "dynamic reference concept" offers a critical and quantitative tool to managers in defining the "possible" targets of recovery in light of rapid ecological changes and climate uncertainty. The project linked this dynamism to long-term ecological dynamics of longleaf pine forests at Eglin Air Force Base in Florida, and it demonstrated the practical application to recovery over 15 years of ecological response to hardwood removal treatments. Furthermore, the findings were incorporated into linked models of habitat and population dynamics of the endangered red-cockaded woodpecker (Picoides borealis).
For more information on these projects, including to view their Final Reports, visit SERDP and ESTCP’s Natural Resources web page.