The Alapaha River Corridor: a high priority wildlife landscape feature

Interesting find by Heather in the State Wildlife Action Plan, July 31, 2015, Georgia Department of Natural Resources, Wildlife Resources Division, featuring the newly-scientifically-recognized Suwannee River alligator snapping turtle. Maybe we’ll see one on the WWALS outing this Sunday from Sasser Landing to Jennings Bluff, and you can preview some of the vegetation mentioned in Julie Bowland’s pictures.

Alapaha River Corridor

The Alapaha River is a nonalluvial (blackwater) river in the Gulf Coastal Plain of Georgia. The Alapaha River corridor includes significant upland habitats associated with sandhill environments. This system includes longleaf pine-scrub oak woodlands, old-growth dwarf pondcypress swamps, mesic hardwood bluffs, and depression ponds. High priority species associated with these habitats include striped newt, gopher frog, gopher tortoise, spotted turtle, eastern indigo snake, eastern diamondbacked rattlesnake, tiger salamander, silky camellia, and pondspice. The Alapaha River is inhabited by the Suwannee River alligator snapping turtle, a distinct, newly described species that is rarer in Georgia than the species found in other drainages. (Note: this conservation landscape spans the Southeastern Plains and Southern Coastal Plain.

Fortunately, the Alapaha River has no dams, but it is vulnerable to groundwater withdrawals and nutrient loadings and susceptible to increased flooding due to drainage ditches, as well as unmanaged recreational uses such as ATVs affecting stream banks. Here’s the context immediately before the above passage.

While invasive exotic species remain rare on the Alapaha, they are already a problem on the Little River and the Withlacoochee River. Similarly for commercial and residential development: the paper calls out Valdosta and Tifton by name. And there are a few suburbs and other developments even on the Alapaha.

Throughout WWALS watersheds, past conversions of forests to row crops and planted pine plantations have affected wildlife diversity and everything else.

On the plus side, Grand Bay is used as the prime example of a wetland well-managed by prescribed fire and water levels. And the Alapaha River remains among the most unaffected areas.

Problems Affecting Wildlife Diversity

Past conversion of forest and woodland habitats to agricultural uses has resulted in the loss of much of the natural upland vegetation in this area. In particular, the more mesic subtypes of longleaf pine-dominated forest/savanna, a predominant vegetation type in pre-settlement times, have been greatly reduced in the landscape. Remaining examples can be found in the Tallahassee Hills region and a few sites elsewhere in the region (e.g., Ichauway Plantation in the Dougherty Plain). More xeric sites (e.g., Fall Line sandhills and xeric aeolian dunes) that are generally unsuitable for agricultural uses still contain intact examples of longleaf pine-scrub oak woodlands and associated habitats. Wetland habitats adjacent to or surrounded by cultivated fields may be impacted by encroachment of soil-disturbing activities or by construction of drainage ditches. Other habitat types impacted by conversion to agricultural uses include forested depression wetlands, canebrakes, and beech-magnolia slope forests.

The uplands of this region are currently employed for a wide variety of agricultural uses, including row crops, orchards, pastures, and hayfields. In some watersheds, particularly in the Dougherty Plain, vegetated stream buffers are often too narrow to provide adequate erosion control. In other areas, intermittent or seasonal headwater streams and seeps have been impacted by encroachment of soil-disturbing practices. These activities result in a general degradation of water quality and habitat for aquatic and wetland species. Expanding vegetated stream buffers and protecting headwater streams would provide significant benefits to some of Georgia’s most imperiled aquatic species as well as species associated with streamside bogs and seeps.

Conversion of upland pine and pine-hardwood forests to pine plantations has also resulted in impacts to wildlife diversity. In some cases, this conversion has resulted in re placement of the original longleaf pine canopy with slash or loblolly pine, while the groundlayer vegetation retains much of the original diversity due to frequent prescribed burns and less intensive site preparation techniques. Where intensive site preparation techniques have been utilized and/or burning has been eliminated as a management tool, much of this native groundlayer diversity has been lost, and habitat suitability for many high priority animals (e.g., red-cockaded woodpecker, Bachman’s sparrow, northern bobwhite quail, gopher tortoise, indigo snake, flatwoods salamander) has been greatly reduced.

Although many landowners within this ecoregion utilize prescribed fire as a management tool, there are some areas in which altered fire regimes constitute a significant problem for wildlife. Expansion of residential and commercial development from urban centers into surrounding suburbs has resulted in many fire-dependent habitats being surrounded by highways, subdivisions, or retail centers. In these areas, concerns about smoke management, air quality, and damage to structures make it difficult to implement prescribed burn plans. In other areas, existing agricultural fields, roads, or utility corridors may isolate fire-dependent wetland communities from forested upland areas that would normally serve as fire source areas.

Extensive peat-bottomed wetland habitats that are difficult to burn are often excluded from prescribed burn plans. Historically, fires in the larger Carolina bays occurred at approximately 25-year intervals. Today, fire exclusion and altered hydrologic conditions have greatly reduced the variety of habitat types represented within depression wetlands. Grand Bay, one of the most extensive wetlands in the state, is maintained primarily by fluctuating water levels along with periodic prescribed fires. This type of management is critical for maintenance of freshwater marsh habitat for the Florida water rat, Florida sandhill crane, and other associated species.

Groundwater and surface water withdrawals for agricultural uses represent significant impacts to wetlands, streams and sensitive karst environments, particularly in the Dougherty Plain. These withdrawals are capable of greatly reducing the hydroperiod of depression wetlands and reducing flows substantially in streams, affecting habitat for a wide variety of rare or declining birds, mussels, fishes, amphibians, reptiles, and plants. In addition, these withdrawals can remove water that would normally from sensitive environments such as caves, springs, and underground streams.

While less prevalent than in other ecoregions, residential and commercial development has resulted in loss of habitats on the periphery of metropolitan areas and along major highways. This is most noticeable in metropolitan areas of Columbus, Albany, Tifton, Valdosta, Warner-Robins, Statesboro, and Augusta. Development pressures have resulted in the loss or fragmentation of a number of upland habitats, alteration of fire regimes, increased sedimentation of streams, and filling or draining of isolated wetlands.

Invasive exotic species pose significant problems to habitats and species in this region. Notable examples include feral hogs, Chinese privet, hydrilla, Japanese climbing fern, cogon grass, and Asian clam. Feral hogs are particularly damaging to understory vegetation in mesic upland hardwood forests, where they feed on roots, tubers, and fruits of a wide variety of herbs, including rare species such as relict trillium. They are also capable of impacting a wide variety of plant species associated with wet pine savannas and herb bogs. Hydrilla is a noxious aquatic weed that has infested shallow water habitats in Lake Seminole, reducing aquatic habitat quality. Japanese climbing fern, a well-known pest in Florida, has gained a foothold in this ecoregion, and cogon grass, a very serious exotic pest plant has recently been documented.

For some high priority species and habitats, unmanaged recreational use represents a serious problem. For example, ATV use in and adjacent to the Ohoopee River may represent a threat to populations of rare mussels such as the Altamaha spinymussel. The potential impacts from this type of recreational use include destabilization of streambanks, excessive sedimentation, pollution from fuel spills, and direct mortality from vehicular impacts. Unmanaged vehicular traffic on xeric aeolian dunes, sandhills, and rock outcrops (e.g., Altamaha Grit) results in damage to the sparse xerophytic vegetation, destabilization of substrates, and direct mortality to rare or declining species such as the gopher tortoise, indigo snake, and eastern diamondback rattlesnake.

Construction of dams or other structures altering stream flow represents a significant problem for high priority species and habitats in this region. Most of the major river impoundments affecting streams and associated wetlands in this area are in the Piedmont (e.g., Lake Sinclair, Lake Oconee, Lake Jackson, West Point Lake, Lake Lanier, Clarks Hill Lake, Jackson Lake), but the regulation of flows on these alluvial river systems results in altered hydroperiods and sediment transport regimes for riverine swamps and bottomland hardwood forests, which in turn affects species composition, structure, and function of these ecosystems. Woodruff Dam at Lake Seminole serves as a barrier for passage of species such as the gulf sturgeon.

Nonalluvial (blackwater) rivers and streams are particularly vulnerable to nutrient loadings and hydrologic disruptions from groundwater and surface water withdrawals, draining of adjacent wetlands, insufficient stream buffers, and other factors. Impacts on these nonalluvial systems include increased flow variability, low dissolved oxygen conditions, increased silt loadings, and resulting stresses to aquatic organisms.

Throughout this ecoregion, depressional wetlands have been impacted by construction of impoundments or drainage ditches. These alterations of natural hydrologic conditions, along with the elimination of fire as a management tool, result in a decline in the number and variety of depression wetland communities.

High Priority Sites and Landscape Features

The current assessment and previous conservation planning efforts have identified a number of ecologically important sites and landscape features in this region of the state. An assessment of the East Gulf Coastal Plain conducted by The Nature Conservancy in cooperation with state natural heritage programs in Alabama, Georgia, Florida, Mississippi, and Louisiana identified 15 high priority areas of conservation interest in Georgia (The Nature Conservancy, 1999). A similar assessment conducted for the South Atlantic Coastal Plain in cooperation with state natural heritage programs in Georgia, Florida, and South Carolina identified 38 high priority conservation areas in Georgia (The Nature Conservancy, 2002). Field surveys conducted by Georgia DNR staff and others have brought additional areas of conservation interest to light in recent years (Edwards et al. 2013). The following list includes examples of significant sites and landscape features in the Southeastern Plains ecoregion.

And the Withlacoochee River gets mentioned once, under “Highest Priority Conservation Actions”:

  • Survey mussels in poorly sampled stream reaches in the Ochlockonee, Withlacoochee and Suwanee basins. Species of interest include Suwanee Moccasinshell, Ochlockonee Mocassinshell, Suwanee Pigtoe, Oval Pigtoe, and Shinyrayed Pocketbook.

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