Discussion and Conclusions

Based on listings from the U.S. Department of Interior (2000), every Southern State contains species that are under Federal protection (figure. 5.7 and figure 5.8). The endangered category refers to species that are in danger of extinction in the foreseeable future throughout significant portions of their range. The threatened designation is assigned to species likely to become endangered in the future. Status determinations are based on modification or restriction of habitat, commercial overutilization, disease or predation pressure, the inadequacy of existing regulations, and other factors affecting continued existence.

There are a number of different explanations for the number of listed species in a State. A State may support many unique habitats with high species richness. Texas is the largest State in the South in both area and species richness. The wide range of environmental conditions and diverse habitats that occur in Texas also support the second highest level of protected species. Larger areas on average support a greater diversity of habitats and a wider variety of species, listed or otherwise.

A species that has been extirpated from adjacent States may persist in areas that support the last remnants of suitable habitat. For example, the red wolf formerly ranged from Texas to the Atlantic Coast. It presently occurs in North Carolina, Tennessee, and Florida, where it has been reintroduced. The Florida panther, another far-ranging mammal, once occurred throughout the region. This species presently is found solely in isolated areas in Florida.

A high number of listed species may also reflect an inherently fragile fauna, such as that in the high-elevation habitats of the Southern Appalachians. It also may reflect a high level of endemic species, such as those associated with scrub habitats of central Florida. Finally, the number of listed species in a State may reflect deteriorating environmental conditions and modification of natural ecosystems, such as longleaf pine forests. Each of these factors contributes to the number of federally protected species in a State. Each reason has bearing on how habitat is managed and protected.

Various natural and human-caused factors contribute to a species imperilment. Some species occur in a very localized geographic area or in a few isolated areas of suitable habitat. These narrowly restricted species tend to be vulnerable to local disturbances that would have little effect on species with wide ranges. The summits and the bogs of the Southern Appalachian Mountains support some highly vulnerable species, such as the northern flying squirrel and the water shrew.

Scattered populations in fragmented habitat can be at risk. They become demographically isolated because they have little or no interaction with other populations. These isolated populations are prone to inbreeding depression and genetic drift, which inhibit viability. Localized populations are also vulnerable to catastrophic events such as floods, droughts, and fires.

Many species have declined because of habitat alteration stemming from human activities. These species are unable to adapt due to changes in habitat features such as vegetative composition and structure and water quality.

Several factors repeatedly surface as threats to terrestrial vertebrates. The most prevalent factor is human development for urban, industrial, and agricultural land uses. Environmental contamination is a second prominent threat, especially in the Southern Appalachians and along the gulf coast. Coastal development contributes to endangerment on both the gulf and Atlantic Coasts. Exploitation occurs primarily on shorelines and in coastal wetlands. Other factors contributing to species endangerment include fire suppression, introduction of exotic species, and the loss of aquatic and wetland habitats.

Habitat loss affects all species, including migrating birds, wide-ranging mammals, and species like the gopher tortoise, which cannot disperse over long distances. Imperiling factors influence species unequally. Turtles are especially vulnerable to human exploitation for food and pets. Bats and snakes are heavily impacted by human disturbance. Beavers and river otters are imperiled by channel modification and impoundments. Environmental contaminants impact the spruce-fir forests used by the northern flying squirrel and the high-elevation mountain streams occupied by a diversity of salamanders. The use of agricultural pesticides affects gamebirds, bats, and amphibians. Wetland alteration affects the Mississippi sandhill crane, mink, and several species of frogs and toads. Lastly, coastal development negatively influences the habitat of the southeastern beach mice, wood storks, marine turtles, and Key deer.

Often, it is difficult to identify a specific factor responsible for the changes observed in a species population. For example, many migratory birds that breed in the South are also dependent on wintering habitats outside of the country. Neotropical migrants are influenced by the loss of wintering habitat in the tropics, while wintering mallard populations are affected by breeding habitat in the prairie pothole region. Therefore, it is vital to understand the temporal and spatial context in which a species occurs. Local changes in the population of species may be a result of dramatic changes in habitat occurring elsewhere.

Maintaining viable populations of southern vertebrate species requires the protection of critical habitat as well as the proactive management of other habitat. Public lands have a key role in species conservation (chapter 1). In some instances, protecting sensitive habitats from further alteration is the best management action. In other instances, active enhancement may be the most appropriate action. For example, treatments may be needed to increase understory growth, create multiple seral stages, restore unique habitats, and control exotic species. Professional foresters, resource managers, and conservationists play an important role in this regard.

There have been notable success stories in managing southern vertebrates. Restrictions on pesticides have improved the status of bald eagles. Red-cockaded woodpeckers have benefited from the management of mature pine forests, provision of artificial cavities, and translocation efforts. River otters and beavers have been restored to areas they formerly inhabited. Alligator populations have rebounded because of management of harvest levels and the protection of wetlands. Many of these species have proven far more resilient and adaptable than once thought.

However, additional efforts are necessary to restore and enhance ecosystem integrity and resiliency on the southern landscape. Management plans should consider the assemblage of reptiles, amphibians, birds, and mammals. Herpetofauna have traditionally received less management attention than other vertebrates. Wetland buffers, travel corridors, and forest composition are important for their viability. Many species are long-lived and late maturing, and have restricted geographic ranges; their management requires different strategies than those used for birds and mammals. Management remains somewhat hindered, however, by the limited knowledge about the status of terrestrial vertebrates and their habitat relationships.

Land ownership patterns associated with the occurrence of southern species have management implications. Approximately 90 percent of the land in the South is privately owned. The protection and management of species habitats can no longer be relegated solely to public land. To be successful, comprehensive conservation strategies require the cooperation of private landowners. Cooperative forestry programs and county extension services are two sources of expertise that contribute to the management of private lands.

In the past few decades, residential and industrial areas have grown rapidly to serve an expanding southern population. Although the extent of southern forests has remained relatively stable in recent years, human and wildlife interactions have increased, and they will continue to do so. Public perceptions about particular species can hinder or foster conservation efforts, highlighting the role of environmental education.

One role for wildlife professionals in the South is to identity the species that face imperilment, determine the actions necessary to eliminate those threats, and then take the necessary actions. Another role is to provide and manage habitat for several game species. The many species inhabiting the southern landscape have a wide variety of habitat requirements; an understanding of these requirements can lead to management plans that promote viable populations and habitat enhancement.