Tennessee: Plants and Wildlife
Changing climate is expected to stress forest ecosystems, and is predicted to cause northward shifts in the geographic distribution of species, community composition, and productivity. With warmer, drier conditions, it is expected that much of the forested land in Tennessee could convert to grassland; increases in warm, moist conditions could alternately cause encroachment of pine and oak species.Populations of Appalachian Spruce in Tennessee are already at high risk due to the effects of acid rain and ground-level ozone, both of which are expected to increase with climate changes. These stands are also impacted by Hemlock Woolly Adelgids, an exotic pest, which is expected to increase in number with lengthened growing season and more mild winters. Under warmer and drier climate regime, conditions required to support Red Spruce and Fraser fir disappear from the landscape in Tennessee. Declines in forestry resources 5%-15% are expected in response to increased thermal stress and decreases in available soil moisture. It is also expected that these effects will increase wildfire occurrence across the southeast region. Changes in forest tree composition and conditions are likely to affect the abundance and diversity of local wildlife. It is possible that the geographic range of wildlife will shift, causing populations to relocate or even causing local extinctions, and allowing invasion of exotic species to the area. Increase in flooding is expected to increase spread of invasive species.
Tennessee freshwater ecosystems support a high diversity of aquatic species. Effects of climate change include decreased diversity, and are expected to be greatest on the species found in the mountainous Cumberland Plateau and Eastern Tennessee, also the locations where the largest number of endemic rare species are found. Increases in surface water temperatures cause a decrease in available dissolved oxygen for aquatic biota. Low levels of dissolved oxygen in freshwater systems have been responsible for fish kills, and are expected to cause loss of aquatic species diversity via local—and possibly global—extinctions in streams, ponds and wetlands. In the drier months of the summer, stream flows may become intermittent, favoring plants and animals favoring ephemeral conditions and eliminating those with long-lasting life cycles. Increases in water temperature will decrease coldwater fish populations as well, such as trout, striped bass, and walleye by limiting range of habitat. Warm-water fish populations are also expected to reduce due to hotter temperatures. Cold-water fisheries at the base of hydropower dams could be impaired by the release of warm water from low-level reservoirs.
Bird species reliant on Tennessee wetlands for habitat and breeding resources are at risk due to changes projected in response to climate change. Game fowl and songbirds are expected to have altered ranges, and some species are expected to disappear entirely. Increased water temperatures are expected to increase the likelihood of invasion of exotic amphibians and reptiles, displacing native species. Range expansions and contractions of several frog species are projected with warmer temperatures, including the Bird-Voiced Treefrog, the Green Treefrog and the Wood Frog. Rare salamander species reliant on cool, humid conditions, such as the Junaluska Salamander and the Pygmy Salamander, are also at risk.