Introduction

The purpose of this guide is to supplement the Project Wild (PW) curriculum with natural history information specific to Georgia.  One of the strengths of the PW curriculum is the breadth of its scope, dealing with issues from around the United States.  This general approach can also be a frustration however, if one is trying to tailor the PW curriculum to local habitats and species that students may encounter in Georgia.

This guide seeks to provide a basic introduction to key habitats and wildlife for each physiographic region within Georgia, and provide references for further study and field trip sites.  Throughout, we have suggested links to local topics and PW activities that could be adjusted to add local information and flavor.  We have accepted the prevailing scientific view of geologic time, though we are aware that other opinions exist regarding the dates of geologic events.  We hope that those who disagree will still find this guide helpful.

We hope this guide helps to generate a greater knowledge and appreciation of Georgias diverse and increasingly threatened habitats.  It is only a deep concern and commitment to these wild places that will ensure their existence for future generations to enjoy.

GEORGIA OVERVIEW
Georgia is the largest state east of the Mississippi River, with a land area of 37 million acres, and is home to over 8 million people (2000 census). This number is expected to increase by 37% over the next 25 years.  The state of Georgia is also home to a remarkably diverse collection of plants and animals. The term biodiversity may inspire images of Australian Coral Reefs and Brazilian Rain Forests, but for certain taxa, the southeastern United States ranks high in the world, and certainly within the United States for sheer number of species.  Georgia is home to 975 vertebrates (ranks 2nd in the nation), of which 63 are found only in Georgia (endemic species).  Georgia ranks among the highest of all states for amphibian, freshwater fishes, and crayfish diversity, and is in the top 10 for reptile and vascular plant diversity (3,600 native plant species).

Many excellent field guides are available that provide detailed information on the identification and life history of our plants and animals.  This guide seeks to introduce you to some of the important plants and animals, not to replace existing guides.
 
CHANGING HABITATS
Walking through a cove forest in the mountains, floating down the Altamaha River by canoe, or wandering the Spanish-moss draped hammock forests on Sapelo Island, one may get a sense of permanence and stability.  This sense is largely an illusion however, as every habitat experiences subtle and sometimes more obvious changes through time.  These change result from internal and external processes.

Internal processes such as plant growth, death, and replacement (called natural succession), are constantly at work, subtly changing every habitat, whether a rock outcrop or a mature forest.  Habitats often progress towards a theoretical "climax" stage, where the species composition remains relatively stable over long periods of time.  If you walk into a forest and the under-story saplings are the same species as the dominant canopy trees, you are witnessing a forest in its climax stage.

External disturbances such as hurricanes, droughts, lightning strikes and fires can interfere with plant succession, setting back the successional clock.  In some habitats, external disturbances occur with sufficient frequency that the climax stage is never reached.  For example, the Longleaf pine forests of the coastal plain are fire-maintained ecosystems, which are rapidly replaced by hardwoods if fire is suppressed.

On a much broader time scale, Georgia's habitats are also changing due to hemispheric and global climate changes.  The most obvious example is the oscillating climate associated with the Ice Ages over the last 2 million years.

PREHISTORIC GEORGIA
Georgias landscape at the peak of the last major Ice Age (20,000 years ago) would be unrecognizable to a modern observer.  Ice ages have occurred about every 100,000 years for the last 2 million years in the northern hemisphere.  A combination of three distinct cycles in the earth's rotation and orbit seem to cause these predictable climatic fluctuations.  Whatever the cause, ice ages dramatically changed the face of North America well beyond the actual extent of ice, which reached only as far south as New York State.

During the ice ages a northern forest of Jack Pine (Pinus sylvestris), Red Pine (Pinus resinosa) and spruce (Picea sp.) found refuge in the southern Appalachians, pushed from its northern range by vast sheets of ice that in places reached 2 miles thick.  Between 14,000 and 11,000 years ago as the climate moderated, the landscape changed, becoming closer in appearance to modern Georgia.

A close look however would reveal a remarkably different fauna. Mastodons (Mammut sp.) grazed in Pine grasslands and spruce forests along the Atlantic coasts, with 4 ton Shasta giant ground-sloths (Nothrotheriops shastensis), and Giant Beaver (Castoroides ohioensis) the size of Black Bear.  Predators such as the Dire Wolf (Canis dirus), American Lions (Panthera leo), American Cheetahs (Miracinonyx sp.), and Saber-toothed Cats (Smilodon fatalis) prowled the landscape as well. In a relatively short period of time between 12,000-9,000 years ago, 35 - 40 species of large mammals went extinct.  The cause of this wave of extinction is still debated today. However, the arrival of Paleo-Indian hunters, approximately 12,000 years ago, probably played a major role in their extinction.

Parallel tales can be told of early human arrival on other continents, such as South America and Australia, where waves of large mammal extinctions followed close on the heels of human hunters.

RECENT HABITAT LOSS
Recent challenges to wildlife are easier to see and understand than prehistoric climate change and Paleo-Indian hunting.  Rapidly expanding human populations exert increasing pressure on wildlife habitat throughout the state. This growing pressure raises concern for the survival of plants and animals that are dependant on the varied natural landscapes of the Southeast.

Habitat provides vital services for wildlife including space, food, water, and shelter. Changes in natural habitats may render them unsuitable for wildlife.  For example, impounding rivers to make lakes alters natural water flow, temperature, and sediment levels, destroying habitat for many of our freshwater species.  Wetland draining has already destroyed about 50% of North Americas wetlands (about 23% of Georgias), threatening the habitat of about 70% of our endangered species.  Water pollution in the form of sediment and chemical pollutants also threaten our native species.

One of our most damaged habitats must be the bottomland hardwood forest. 77% of our bottomland hardwood forests have been cleared over the last 2 centuries, leading to the recent extinction of 3 of 5 bird species that depend exclusively on this habitat.  North Americas largest woodpecker (Ivory-billed Campephilus principalis), North Americas only native parrot (Carolina parakeet Conuropsis carolinensis), and the Bachmans Warbler (Vermivora bachmanii) have all become extinct.  The brilliant Prothonotary Warbler (Prothonotaria citrea) and skulking Swainsons Warbler (Lymnothlypis swainsonii) remain, although both are species of concern due to habitat loss. 

GEORGIAS PHYSIOGRAPHIC REGIONS
From the southern terminus of the Appalachian Mountains to the barrier islands, Georgia includes a wide range of habitats and landscapes.  This diversity supports the vast array of plants and animals that make our state unique. This guide divides Georgia into six regions, including three mountain regions, the piedmont, coastal plain, and barrier islands.  Each region is defined by its underlying geology, soil types and topography.  These physical factors in conjunction with climate (long term weather patterns) and local disturbances (storms, fires and floods), determine the types of habitats that develop in each region. The central role of soils, climate and natural disturbance will be revisited again and again, as these three factors determine what plants and animals can become established in any given habitat.

This guide starts in the mountains and moves to the coast, as if one were hiking from the mountains of northwest Georgia to the sea.  This cross-section of Georgia would be wedge shaped, with the high tumbled rocks of the mountains gradually softening to the rolling piedmont, and then dropping to the essentially flat coastal plain and ocean.