Ecosystem Vulnerability to Climate Change in the 

Southeastern United States

Two recent investigations of climate-change vulnerability for 19 terrestrial, aquatic, riparian, and coastal 

ecosystems of the southeastern United States have identified a number of important considerations, including 

potential for changes in hydrology, disturbance regimes, and interspecies interactions. Complementary approaches 

using geospatial analysis and literature synthesis integrated information on ecosystem biogeography and 

biodiversity, climate projections, vegetation dynamics, soil and water characteristics, anthropogenic threats, 

conservation status, sea-level rise, and coastal flooding impacts. Across a diverse set of ecosystems—ranging in 

size from dozens of square meters to thousands of square kilometers—quantitative and qualitative assessments 

identified types of climate-change exposure, evaluated sensitivity, and explored potential adaptive capacity. These 

analyses highlighted key gaps in scientific understanding and suggested priorities for future research. Together, 

these studies help create a foundation for ecosystem-level analysis of climate-change vulnerability to support 

effective biodiversity conservation in the southeastern United States.

Examples of ecosystems that were analyzed to assess climate-change vulnerability included, A, montane grass and heath balds, B, granite outcrops, 

C, longleaf pine savannas, and D, flood-scoured riparian areas. 

All photographs by Alan Cressler, U.S. Geological Survey.

A

C

B

D

U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2016–3052

August 2016
Introduction

Assessments of climate-change vulnerability (bold

terms can be found in the glossary) are becoming increasingly 

important to the conservation of biodiversity. Increasing regional 

temperatures and changing precipitation patterns are already 

affecting many plant and animal species, and these effects are 

expected to become more pronounced in the decades ahead. 

Ecological effects of climate change have been documented 

around the world, ranging from changes in species phenology

to shifts in plant and animal distributions to altered wildfire 

dynamics. To target conservation strategies effectively, natural 

resource managers need timely and comprehensive information 

concerning climate-change effects on natural communities, 

including current assessments and future projections. This 

is especially true in regions that are rich in plant and animal 

biodiversity, such as the southeastern United States.

Although climate-change vulnerability assessments for 

individual species are common and important conservation tools, 

assessments for whole ecosystems offer a number of important 

advantages. Ecosystem-level assessments allow for more 

comprehensive and holistic views of ecological processes and 

drivers of change than do species-level assessments, for example 

by incorporating climate-induced changes in disturbance

dynamics, hydrologic conditions, and geomorphic processes. 

In addition, ecosystem-level assessments can readily incorporate 

interspecies interactions, including food webs, competition, pest 

and pathogen dynamics, and exotic species invasions.

Two recent U.S. Geological Survey reports (Cartwright 

and Wolfe, 2016; Costanza and others, 2016) collectively 

address climate-change vulnerability for 19 terrestrial, aquatic, 

riparian, and coastal ecosystems across the diverse landscapes 

of the southeastern United States. Ranging from Appalachian 

mountain tops to Texas canyons to Caribbean mangroves, these 

ecosystems were assessed by integrating current scientific 

knowledge on a broad range of factors, including

• Ecosystem biogeography and distribution

• Ecological processes and habitat characteristics

• Plant community types and vegetation dynamics

• Abiotic stress factors such as hydrologic variability, soil 

and water chemistry, topography, and temperature ranges

• Disturbance regimes including wildfire and riparian 

flood scouring

• Biodiversity, including plant and animal species of 

conservation concern

• Human threats, such as resource extraction and 

land-use change

• Conservation strategies and options

• Knowledge gaps and research priorities

Complementary Approaches: A Question of Scale 

and Biogeography

Investigations by Costanza and others (2016) and Cartwright

and Wolfe (2016) represent a unified effort to develop preliminary

frameworks for ecosystem-level climate-change vulnerability 

assessment across the southeastern United States; however, the 

two studies necessarily employed different and complementary 

approaches. In large part, these approaches were determined by 

considerations of geographic scale, biogeography, data resolution,

and availability of published literature for each ecosystem. 

Geospatial Analysis Across Broad Geographic Extents

Costanza and others (2016) assessed exposure, sensitivity, 

and adaptive capacity to climate change using geospatial 

analysis for several ecosystems such as wet pine savannas and 

hardwood forests. Geospatial datasets used in the assessment 

included climate projections, current and projected land use, 

elevation, ecosystem fragmentation, protection status, sea-level 

rise and coastal flooding impacts, and models of vegetation 

dynamics. This approach is well-suited to ecosystems with broad 

geographic extent, for which such datasets can be obtained 

and models can be run at appropriate spatial resolution. Where 

geospatial data to address aspects of climate-change exposure, 

sensitivity, or adaptive capacity were lacking, Costanza and 

others (2016) used publications to fill gaps in the analysis.

Exposure Sensitivity

Climate-change

vulnerability

Potential

impact

Adaptive

capacity

Ecosystem-level analyses by Costanza and others (2016) 

were based on a climate-change vulnerability framework 

incorporating exposure, sensitivity, and adaptive capacity.

Literature Synthesis for Ecological Islands

Cartwright and Wolfe (2016) focused on a set of 

“insular” ecosystems, characterized by small land area, 

geographic discreteness (spatially isolated like islands in a 

sea of contrasting ecosystems), sharply defined boundaries, 

and biogeographic distributions strongly linked to specific 

geologic, geomorphic, and soil characteristics. These 

ecosystems included rock outcrops, insular prairies and 

barrens, geographically isolated wetlands, and flood-scoured 

riparian zones. For these systems, existing geospatial data 

were generally of insufficient spatial resolution to support 

robust geospatial analysis. Numerous localized, site-specific 

investigations in these ecosystems over several decades have 

yielded valuable botanical and ecological information, but 

this literature has generally remained disconnected and has 

rarely addressed climate change. Therefore, Cartwright and 

Wolfe (2016) performed a comprehensive synthesis of the 

literature for selected insular ecosystems to lay the necessary 

groundwork for future explorations of climate-change effects 

on ecosystem function.
Collectively, the analyses by Costanza and others (2016) 

and Cartwright and Wolfe (2016) incorporate both quantitative 

and qualitative approaches, draw from a diverse array of data and 

information sources, and focus on ecosystems ranging in size 

from dozens of square meters to thousands of square kilometers 

across the diverse ecoregions of the southeastern United States.

Components and Consequences of Ecosystem 

Response to Climate Change

Although the analyses by Cartwright and Wolfe (2016) and 

Costanza and others (2016) employed different approaches and 

largely addressed different ecosystems, several key findings are 

common to both studies:

• Climate-change effects on ecosystems are likely to be driven by 

interactions of multiple processes at local to landscape scales. 

In addition to regional temperature increases and precipitation 

change, these processes may include local alterations of 

disturbance regimes, urbanization, contaminant release, local or 

regional hydrologic change, and altered interspecies interactions.

• Ecosystem responses to climate change have the potential to 

adversely affect species of conservation concern, especially 

rare and range-restricted species such as herbaceous plants 

endemic to insular ecosystems (see photos below).

• Ecosystem fragmentation—whether naturally occurring as 

in the case of ecological islands or an outcome of land-use 

change—is likely to degrade the adaptive capacities of 

ecosystems in response to climate stressors. Fragmentation 

increases the dispersal distances required for species 

migrations to newly suitable habitats in response to 

changing climate conditions and increases the potential for 

edge effects, such as encroachment by competitors and loss 

of core habitat for sensitive species.

• In many cases, current estimates of ecosystem exposure, 

sensitivity, and adaptive capacity to climate change 

are subject to high levels of uncertainty. In particular, 

differences in projected precipitation patterns across 

downscaled climate forecasts—combined with knowledge 

gaps concerning key hydrologic processes such as 

evapotranspiration and groundwater-surface water 

interaction—complicate efforts to predict ecosystem-level 

hydrologic change. In addition, information is lacking for 

many ecosystems on the relations between climate drivers 

and key interspecies interactions, such as pollination, food 

webs, and competition.

• Associations between biodiversity and particular landforms, 

such as rock outcrops and depression wetlands, highlight the 

value of conserving geodiversity.

A number of range-restricted species of conservation concern are endemic to the ecosystems analyzed by Cartwright 

and Wolfe (2016) and Costanza and others (2016), including, A, Pyne’s ground plum (limestone cedar glades), B, Millboro 

leatherflower (mid-Appalachian shale barrens), C, Spreading avens (high-elevation outcrops of the southern Appalachian 

mountains), and D, Cumberland false rosemary (riverscour ecosystems on the Cumberland Plateau).

Photographs A and C by Alan Cressler, U.S. Geological Survey. Photograph B by Irvine Wilson, Virginia Department of Conservation and Recreation. Photograph D by Nora Murdock, National Park Service.

A

C

B

D
Research Priorities for Future Investigations

To effectively conserve biodiversity in the face of climate

change, natural resource managers require timely and 

accurate predictions of ecological response at the level of 

whole ecosystems, not just individual species. To improve 

these predictions, Cartwright and Wolfe (2016) and Costanza 

and others (2016) proposed a set of research priorities to 

guide future investigations. In particular, hypothesis-driven 

empirical investigations are needed concerning (1) effects of 

hydrologic change on ecosystem function, (2) interactions 

between multiple types of biotic and abiotic change, for 

example increased soil temperature combined with increased 

drought frequency, (3) climatic determinants of interspecies 

interactions including potential for phenological mismatch, 

(4) climate-change effects on adaptive management options, 

for example changes in availability of suitable weather 

conditions for prescribed burning, and (5) effects of scale 

and spatial resolution on modeled forecasts of ecosystem 

change. Efforts to address these research priorities will ideally 

incorporate a variety of methods and approaches, including 

geospatial analysis, climate and vegetation modeling, 

literature synthesis, and expert opinion.

References Cited 

Cartwright, J.M., and Wolfe, W.J., 2016, Insular ecosystems 

of the southeastern United States—A regional synthesis to 

support biodiversity conservation in a changing climate: 

U.S. Geological Survey Professional Paper 1828, 162 p., 

http://dx.doi.org/10.3133/pp1828.

Costanza, Jennifer, Beck, Scott, Pyne, Milo, Terando, Adam, 

Rubino, Matthew, White, Rickie, and Collazo, Jaime, 

2016, Assessing climate-sensitive ecosystems in the 

southeastern United States: U.S. Geological Survey 

Open-File Report 2016 –1073, 278 p., http://dx.doi.org/

10.3133/ofr20161073.

Glossary

adaptive capacity The ability of species or populations to cope with climate change, such as through 

physiological changes, migration, or exploitation of 

new microhabitats.

climate-change vulnerability The susceptibility of

an ecosystem to negative effects from changing 

climate conditions.

dispersal The movement of individual plants or 

animals or their reproductive structures from one 

geographic area to another. 

distribution The spatial arrangement of a plant or 

animal species across a geographic area.

disturbance An event or series of events—such 

as fires or floods—producing intense environmental 

stress over a relatively short period of time.

endemic Primarily restricted to a particular ecosystem.

exposure The magnitude and rate of change in climate 

variables or sea level experienced by an ecosystem in 

the future.

fragmentation The degree to which an ecosystem is 

spatially divided into a greater number of small, isolated 

patches rather than one large, continuous habitat.

geodiversity diversity of landforms, topography, soil, 

and bedrock 

phenological mismatch A disruption in an interspecies 

interaction, such as pollination, resulting from changes 

in phenology.

phenology The seasonal timing of life-cycle events, 

such as bud-burst or nesting.

sensitivity The degree to which the ecological integrity 

of an ecosystem depends upon climate conditions. 

Authors:

Jennifer M. Cartwright

U.S. Geological Survey

Lower Mississippi-Gulf Water Science Center

jmcart@usgs.gov

Jennifer Costanza

Department of Forestry and Environmental Resources

North Carolina State University

jkcostan@ncsu.edu

For additional information contact:

U.S. Department of the Interior

Southeast Climate Science Center

North Carolina State University

127 David Clark Labs

Campus Box 7617

Raleigh, NC 27695

https://globalchange.ncsu.edu/secsc/

Wildfires and controlled burns are forms of disturbance that are vital to a 

number of ecosystems of the southeastern United States. The influence 

of climate change on disturbance dynamics is an important frontier 

of research. 

Photograph by Alan Cressler, U.S. Geological Survey.

ISSN 2327-6916 (print)

ISSN 2327-6932 (online)

http://dx.doi.org/10.3133/fs20163052