William Conner, Ph.D. - Research & Projects

Ecology and Management of Forested Wetland Ecosystems of the Southern United States

Summary

Forested wetlands have been an influential component of the economy and culture of the southern United States since the earliest settlements. These ecosystems have been used for transportation, food and fiber, flood control, wildlife habitat, recreation, and all too often, a fertile site for conversion to agriculture. The importance of wetlands to the southern economy and concern over their decreasing extent has lead to a surge of research activity as well as litigation and discord over competing wetland uses. Hydrology is one of the most important driving forces in forested wetlands, and the length, depth, and timing of flooding determines the diversity and productivity of these systems. Changes in normal hydrology patterns due to stream channelization or construction of roads, canals, levees, or dams affect the establishment and growth of forest species. Another aspect of hydrology that needs consideration, especially in coastal areas, is eustatic sea level rise and subsidence. The long-term impacts of disturbance is a major area of research in Dr. Conner’s program.  Only long-term research can consider both the short- and long-term fluctuations of key driving forces. In addition, Dr. Conner is examining processes across the entire southern United States to determine if all wetlands function similarly.

 

Projects

Hydrologic and Biological Study of Four Hole Swamp Fringe Area (2009-2011), National Audubon Society Funding
William Conner (Clemson University) & Dan Tufford (University of South Carolina)

A three-year baseline data study on hydrologic and biological conditions is being conducted to evaluate the effects of mitigation proposed by Holcim Quarry to compensate for loss of wetlands and streams in conjunction with a proposed quarry expansion. The baseline data will address forest productivity, vegetation community structure, shallow subsurface hydrology, water table response to precipitation, water table water quality, seasonal and interannual variability, and trends in these metrics. Dr. Conner’s research includes field inventories of the various forest types (cypress/tupelo slough to upland pine/hardwood stands) to evaluate the structure and composition of permanent plots to establish patterns of tree density, stature, size-class relations, crown condition, and viability status in forest sites. In addition, aboveground net primary productivity of the forests is being measured though tree growth and litterfall studies.

Enhancement of Suppressed Baldcypress (Taxodium distichum) Growth on the Roanoke River National Wildlife Refuge, North Carolina (2007-2011), USGS Funding, William Conner (Clemson University)

The floodplain forests along the Roanoke River in North Carolina were extensively logged for baldcypress during the late 19th-early 20th century. The result of past logging activities can be seen today in swamp forests that are now dominated by thick stands of water tupelo with relatively few baldcypress trees present. However, scattered throughout the floodplain are small pockets of 3-4 meter tall baldcypress trees shaded by the towering water tupelo trees. The purpose of this project is to reduce the canopy cover of water tupelo around the pockets of suppressed baldcypress trees in an effort to provide the necessary light and space to allow the trees to reach canopy height. The specific objective of this project is to assess impacts of canopy opening on growth dynamics of tagged and banded baldcypress trees to develop and improve habitat restoration techniques.

Climate Change and Tidally Influenced Freshwater Forested Wetlands of the Southeast: Understanding Functional Ecological Attributes of Forest Transitions to Marsh (2009-2013), USGS – GCC funding, William Conner (Clemson University)

Tidal freshwater forested wetlands are unique ecosystems that provide an opportunity for understanding the unique structuring of freshwater forests along hydroperiod, salinity, and microtopographical gradients. The goal of this project is to take a regional approach in studying community dynamics of tidal freshwater forested wetlands to understand the ecology and potential effects of sea-level rise on this ecosystem. Study plots were established in a previous GCC project (Dieback and Restoration of Coastal Forests of the Southeast Under Changing Climate; Interactive Effects of Drought Severity, Hurricanes, Sea-Level Rise and Coastal Management) in tidal freshwater swamps with varying tidal influence in riverine and non-riverine watersheds in coastal South Carolina. Plots extended from healthy to stressed cypress-tupelo communities and consisted of cypress stands located along a transect gradient from fresh to brackish environments. Monthly field trips are made to the sites to collect tree growth, litterfall, water level, and soil salinity data. Further, additional data regarding microhabitat use and availability will be collected, and distinct strategies of species preference for microsite will be elucidated through dedicated whole-tree eco-physiological studies. This study will increase our understanding of tidal freshwater forested wetlands at the regional level, thereby providing a better base of knowledge from which future management goals can draw. A broad understanding of community composition, their associations with soil and hydrology, and usage of microtopography will help direct future restoration and mitigation efforts. Learning the physiology associated with water transport in trees under differing environmental conditions will allow us to understand the specific physiological requirements of trees at different microtopographic and landscape positions. This knowledge, in turn, will help balance municipal river-water use with environmental responses to flow management. These advancements will increase our ability to sustain ecosystem health, conserve and preserve wildlife, and minimize relative sea-level rise by enhancing long-term carbon sequestration.

 

Program of Integrated Study for Coastal Environmental Sustainability (PISCES), William Conner (Clemson University)

PISCES is a unique program designed to address environmental sustainability issues that can accompany coastal development. Instead of reacting to mitigate environmental issues after developments are finished, researchers will establish monitoring projects before construction begins in an attempt to better understand how to manage sensitive coastal systems. The developers of Bannockburn Plantation are partnering with scientists from Clemson University's Baruch Institute of Coastal Ecology and Forest Science in a continuing effort to understand and minimize the impacts of development on the environment. PISCES scientists will study water quality, wetlands, forests, hydrology, wildlife, and historical ecology on the property before, during, and after construction to document how these natural aspects change as development progresses.

 

Page maintained by: Dawn White, dawnw@clemson.edu