Baldcypress Swamp Management and 

Climate Change

Open-File Report 2006-1269

U.S. Department of the Interior

U.S. Geological Survey
Baldcypress Swamp Management and Climate 

Change 

By Beth A. Middleton 

Open-File Report 2006–1269 

U.S. Department of the Interior 

U.S. Geological Survey
U.S. Department of the Interior 

DIRK KEMPTHORNE, Secretary 

U.S. Geological Survey 

P. Patrick Leahy, Acting Director 

U.S. Geological Survey, Reston, Virginia 2006 

For product and ordering information: 

World Wide Web: http://www.usgs.gov/pubprod 

Telephone: 1-888-ASK-USGS 

For more information on the USGS—the Federal source for science about the Earth, 

its natural and living resources, natural hazards, and the environment: 

World Wide Web: http://www.usgs.gov 

Telephone: 1-888-ASK-USGS 

Suggested citation: 

Middleton, B.A., 2006, Baldcypress swamp management and climate change: U.S. Geological 

Survey Open-File Report 2006-1269, 3 p. 

Any use of trade, product, or firm names is for descriptive purposes only and does not imply 

endorsement by the U.S. Government. 

ii 
Contents 

Baldcypress Swamp Management and Climate Change ........................................................................................... 1 

References Cited................................................................................................................................................................ 3

Figures 

1. Total litterfall rates in baldcypress (Taxodium distichum ) swamps at various latitudes................................. 1 

2. Overcup oak (Quercus lyrata) dispersing in the water.. ......................................................................................... 3

iii 
Baldcypress Swamp Management and Climate 

Change 

By Beth A. Middleton1

 In the future, climates may become warmer and drier in the southeastern United States; as 

a result, the range of baldcypress (Taxodium distichum) swamps may shrink. Managers of 

baldcypress swamps at the southern edge of the range may face special challenges in attempting 

to preserve these swamp habitats in the future if climates become warmer and drier. Climate 

warming and drying would likely result in the loss of some southern populations of baldcypress 

swamps, and the populations most vulnerable are in Texas (Middleton and McKee, 2004) and 

south Florida (Crumpacker and others, 2001). Near the edge of the range of baldcypress 

swamps, leaf litter production is lower (fig. 1; Middleton and McKee, 2004), and tree 

regeneration is poorer (Middleton, unpublished data), indicating stressed growing conditions. 

Figure 1. Total litterfall rates measured in baldcypress (Taxodium distichum) swamps at various latitudes. Swamps 

with natural (•) and impaired (•) hydrology are plotted separately (Middleton and McKee, 2004). A second-order 

polynomial curve was fitted to the data (SAS JMP, 2003). Reprinted by permission of Global Ecology and 

Biogeography. 

 

1

U.S. Geological Survey, National Wetlands Research Center, 700 Cajundome Boulevard, Lafayette, LA 70506
A modest climate change of 20 percent to 30 percent climate drying by 2030 and 2060, 

respectively in the southeastern United States, is predicted by the GCMI model (Hengeveld, 

2000), and climate drying would have negative effects on the ability of swamp species to 

regenerate themselves. 

Climate change may have severe effects on the ability of baldcypress swamp species to 

regenerate themselves. At the present time, many more viable seeds of baldcypress trees are 

found in the seed banks from the northern part of the range, either because seed production rates 

are higher or because seeds may be stored for somewhat longer periods of time in Tennessee and 

northward (e.g., Cache River, Ill., and Reelfoot Lake, Tenn; Middleton unpublished data). A 

reduction in precipitation may reduce the seed bank density of important herbaceous swamp 

species including Aster sp., Cyperus erythrorhizos, Eupatorium sp., Fimbristylis miliacea, 

Hottonia inflata, Mitreola petiolata, and Phyla lanceolata to unsustainable levels (Middleton 

unpublished data). Recruitment of many species is dependent on moisture conditions in the soil 

(Middleton, 1999, 2003), and seed density in the seed bank is an important component of the 

regeneration process. Changes in climate patterns could have a big impact on the process of 

swamp forest regeneration. 

The effects of climate drying may cause problems for managers, particularly because 

certain rare species may become less common and certain undesirable species may become more 

common in the seed bank. For example, H. inflata is a rare species in the northern part of its 

swamp range and a State-listed species in many localities, and climate drying reduces its seed 

density in the soil. Of special concern is that climate drying may increase the seed bank density 

of buttonbush (Cephalanthus occidentalis), a native but undesirable species among wildlife and 

fisheries managers. Climate change will shift management priorities for managers. 

Managers of baldcypress swamps at the southern extreme of their range are likely to face 

the loss of biodiversity in these swamps as species become unable to deal with predicted hotter 

and drier conditions through regional habitat reduction and invasive species intrusion. Coastal 

saltwater intrusion is likely in coastal swamps if sea levels rise, and this situation poses particular 

problems to managers. Managers in the middle of the baldcypress swamp range may face a 

partial loss of habitat via declining production and loss of biodiversity. 

Managers should be prepared for potential changes caused by climate change in refuges 

so that they can proactively address the situation. If climates become warmer and drier in the 

Southeast in the future, species may not be able to move northward fast enough to avoid local 

extirpation because aquatic seeds disperse southward on rivers (fig. 2; Middleton, 2003). 

Managers involved in restoration projects outside of the current range of baldcypress swamps 

might want to reconsider which species they use, depending on which species are best suited for 

the climate. In regions at the edge of the baldcypress swamp range, species from just outside of 

the current range might grow better in restoration plots. For example, managers in south-central 

Illinois could try planting some plots with species from baldcypress swamps, which are outside 

of the range currently considered. Similarly, managers in Texas might plant species from farther 

southwest. The idea of using species for restoration that are best suited to the climate is not 

tested in the field; however, theoretical studies support such practices (Middleton and McKee 

2004). If climate change is a reality, then the situation should become apparent via changing 

patterns of production, regeneration, and species distribution. 

2 
 

Figure 2. Overcup oak (Quercus lyrata) dispersing in water. Seed dispersal and germination may be hampered by 

climate drying. 

References Cited 

Crumpacker, D.W., Box, E.O., and Hardin, E.D., 2001, Temperate-subtropical transition areas 

for native woody plant species in Florida, U.S.A.: present locations, predicted changes 

under climatic warming, and implications for conservation: Natural Areas Journal, v. 21, 

p. 136 - 148. 

Hengeveld, H., 2000, Projections for Canada's climate future. Climate change digest CCD 00-01: 

Downsview, Ontario, Environment Canada, Meteorological Service of Canada, 27 p. 

Middleton, B.A., 1999, Wetland restoration, flood pulsing and disturbance dynamics: New York, 

New York, John Wiley and Sons, 400 p. 

Middleton, B.A., 2003, Soil seed banks and the potential restoration of forested wetlands after 

farming: Journal of Applied Ecology, v. 40, p. 1025 - 1034. 

Middleton, B.A., and McKee, K.L., 2004, Use of a latitudinal gradient in bald cypress 

production to examine physiological controls on biotic boundaries and potential 

responses to environmental change: Global Ecology and Biogeography, v. 13, p. 247 - 

258. 

SAS JMP, 2003, JMP statistics and graphics guide. Version 5.0.1: Cary, N.C., Statistical 

Analysis System, 634 p. 

3