We developed a multifactor ecological classification system (ECS) for the National Forests and adjacent lands of Texas and Louisiana. The ECS classifies lands into ecosystem types: repeating combinations of potential natural vegetation, soils, and physiography. This paper uses results of a portion of this effort from the northern part of Louisiana's Kisatchie National Forest as an example. Forest stands were sampled across a range of soil and topographic situations. Non-metric multidimensional scaling ordinations and TWINSPAN classification of the samples based on ground-layer vegetation corresponded to gradients of topographic position, fire frequency, disturbance, and soil nutrients. A separate ordination of only upland stands clarified relationships between upland vegetation and soil texture. Ordination and TWINSPAN results formed the basis for a final classification of the sample stands and for descriptions and dichotomous keys for seven “land-type phases”—local ecosystem types that share soil and topographic attributes, natural plant communities, and responses to management or disturbance. ECS provides an ecologically relevant way to stratify the landscape for inventory, conservation, research, or management and gives the Forest Service and other professionals a valuable tool to aid in making ecologically informed decisions. Future goals include mapping ecological units on National Forest lands and expansion of the area covered.

In 1998, we conducted a radio-telemetry study of Coluber constrictor etheridgei (Tan Racer) in the Angelina National Forest in eastern Texas. Individuals were located once daily from 12 June to 14 August. We determined home-range size, movement distances, movement frequency, and habitat use for this short-term study. We also determined food habits of this population by examination of fecal samples. We compared these parameters to other Racer taxa in Utah (C. c. mormon [Western Yellow-bellied Racer]), Kansas (C. c. flaviventris [Eastern Yellow-bellied Racer]), and South Carolina (C. c. priapus [Southern Black Racer]). Compared to these populations, Texas Racers exhibited larger home ranges and greater movement frequency and distances during the summer than Utah or Kansas populations, but approximately equal to those of the South Carolina population. Available data on food habits suggests that all populations are consumers of invertebrate and vertebrate prey. We hypothesize that the basic diet of C. constrictor is composed of invertebrates captured by active foraging in areas of abundant herbaceous vegetation, that differences in home-range size and movement distances result from variations in patchiness of suitable foraging habitat across populations, and that the proportion of vertebrate prey in the diet of Coluber populations increases as home-range size and movement distances increase due to increasing patchiness of foraging habitat, resulting in increasing encounters with vertebrate prey.

Elaphe spp. (ratsnakes) are frequent predators on cavity-nesting birds and other vertebrates, including Glaucomys volons (Southern Flying Squirrels). They are known predators of Picoides borealis (Red-cockaded Woodpeckers), especially during the nestling phase. Picoides borealis cavities are frequently occupied by Southern Flying Squirrels, often several squirrels per cavity. Behavioral aspects of ratsnake predation on flying squirrels in woodpecker cavities is an important component required for a full understanding of the potentially complex interaction between Red-cockaded Woodpeckers, Southern Flying Squirrels, and ratsnakes. We induced previously captured Elaphe obsoleta (Texas Ratsnake) to climb boles of pine trees and gain access to Red-cockaded Woodpecker cavities known to contain Southern Flying Squirrels, and observed the resulting predatory interactions. Eight of nine ratsnakes successfully captured 14 of 22 Southern Flying Squirrels present in the cavities.

During winter, aerial surveys are used to estimate densities of ducks that occupy open-water habitats. However, such surveys are ineffective for sampling forest-dwelling species, especially Aix sponsa (Wood Ducks), Anas platyrhynchos (Mallards), and Lophodytes cucullatus (Hooded Mergansers). We evaluated fixed-radius plot (FRP) and Reynolds and Goodrum variable-radius plot (VRP) methods for estimating waterfowl densities in a flooded hardwood bottomland. We constructed 15 elevated blinds on the Angelina River flood plain in eastern Texas and established a 1-ha FRP around each blind; color-coded markers were placed at fixed intervals from each blind. Observers surveyed waterfowl from blinds for 21 mornings during January–March, 1990. For FRPs, species, sex, and time a bird entered and exited the plot were recorded. For VRPs, similar data and estimated observer-to-bird distance were recorded. Data were arranged in a randomized block design and tested using 1-way analyses of variances. Wood Ducks, Mallards, and Hooded Mergansers comprised 68, 18, and 10% of the birds recorded, respectively. Wood Duck density estimates (per ha) for FRP, Reynolds VRP, and Goodrum VRP methods were 0.65, 0.49, and 1.00 (P < 0.001), respectively; for Mallards, estimates were 0.27, 0.20, and 0.33 (P < 0.001), respectively; and estimates were 0.09, 0.13, and 0.15 (P = 0.003) for Hooded Mergansers, respectively. Based on ease of implementation, complexity of data analyses, and precision of density estimates, the FRP and Goodrum VRP methods are recommended for sampling waterfowl in flooded forests.

We initiated a mark-recapture study to determine the effects of shrub density on Anolis carolinensis (Green Anole) populations. Green Anole perch site, shrub species, and shrub volume preferences were also examined. We established two study plots of different shrub densities in open pine forests on the Angelina National Forest in eastern Texas. In late spring, the Green Anole population at the higher shrub-density plot was estimated to be 16 times greater than the population at the lower shrub-density plot. Green Anoles most commonly perched on live shrubs, but exhibited very little preference or avoidance of any particular species of live shrub or shrub-level vine. However, shrubs used by Green Anoles were 4–6 times greater in volume than plot averages.

Ants of the tribe Dacetini are especially diverse in Southeastern North America, with 40 known species, all in the genera Pyramica and Strumigenys. The 30 native Pyramica may represent a remnant Arctotertiary forest ant fauna. The 9 introduced species of Pyramica and Strumigenys come from both Old and New World tropics. Surveys of the southeastern fauna appear incomplete, and there may be additional undescribed species. All species are predatory, capturing small arthropods, especially Collembola, by means of a specialized jaw-snapping mechanism. The notable diversity in mandibular structure among species is unexplained in a functional sense. Arrays of specialized clypeal hairs, usually species-specific, may possibly lure prey. Specialized “spongiform bodies” in the petiolar area may be defensive. Local populations may be threatened by habitat loss, invasive exotic species, and climate change.

Maps of wild or roadless areas in North America show that most lie west of the Mississippi River. The Everglades is one exception. Yet there are others. Using existing data, I draw attention to four large areas in the southeast that are worthy of national as well as regional attention. These four (Eglin: 187,000 ha; Apalachicola: 228,000 ha; Okefenokee-Oceola: 289,000 ha; De Soto: 200,000 ha) have nearby lands that offer the potential to expand the total protected territory for each area to well beyond 500,000 ha. From the North American perspective, these areas are essential elements of a national conservation plan. These areas urgently need (1) land acquisition to link with nearby protected lands and establish ecologically meaningful boundaries, (2) restoration of natural forces (particularly flooding and fire), and (3) forestry practices focused upon restoration.

The limits of species ranges can be determined by a number of biotic and abiotic interactions, and in areas where closely related species overlap, some degree of reproductive isolation must exist in order for them to remain distinct. Understanding these interactions is essential for understanding what limits species distributions or causes hybridization. Fundulus heteroclitus (Mummichog) and Fundulus grandis (Gulf Killifish) are two closely related species with similar morphologies and ecological niches. Both species have widespread distributions that overlap in northeastern Florida. In the present study, two highly divergent loci (one nuclear and one mitochondrial) were utilized to distinguish these fundulid species in order to identify their ranges and to detect hybrids. Analysis of specimens collected along a north to south gradient in northeastern Florida salt marshes established that a relatively sharp transition (≈38 km) from relatively pure Mummichog populations to relatively pure F. grandis populations existed south of Jacksonville, FL, centered near Flagler Beach, FL. Putative hybrid genotypes were detected at moderate frequencies within the contact zone, suggesting that successful hybridization is likely occurring between the two species, but is relatively uncommon. These results provide a stepping stone to investigate the types of reproductive barriers that are involved in maintaining species distinctions in this system and their effects on the species' ranges and ecological interactions.

Ptychobranchus jonesi (Southern Kidneyshell) is one of the most imperiled freshwater mussels in North America. It is endemic to eastern Gulf of Mexico drainages from the Escambia to the Choctawhatchee River basins. Numerous recent surveys considered it restricted to a single population in the West Fork Choctawhatchee River in southeastern Alabama. We conducted comprehensive (9–15 hr per site) mussel searches in three high-quality reaches of the Pea River, a Choctawhatchee River tributary, to assess microhabitat associations for the Southern Kidneyshell. Habitat features were later used to identify subsequent search localities. We found undetected Southern Kidneyshell populations at a total of seven localities in the Choctawhatchee River Basin, AL. Although widely-distributed, the Southern Kidneyshell is extremely rare (n = 13) and comprised <0.3% of all mussels encountered. Prior surveys may have underestimated the distribution of the Southern Kidneyshell because they were broadly focused and thus did not expend the necessary effort to detect this rare mussel. Targeted searches in preferred microhabitats greatly increased Southern Kidneyshell catch rates and were used to detect four of the seven new populations. These results suggest that extensive searches within high-quality habitats are critical to detecting rare mussels in patchy habitats.

Water column turbidity, chlorophyll-a content, and dissolved inorganic macronutrients were measured in Ross Barnett Reservoir, a turbid, artificial water body located in central Mississippi. Measurements indicated that abundant nutrients were present, whereas levels of chlorophyll-a were substantially below expectation. Significant inorganic turbidity and the resulting low transparency suggested rapid extinction of light within the water column. Sediment settling in an experimental microcosm led to rapid increase in chlorophyll-a, consistent with the notion that algal biomass abundance was limited by light, rather than nutrients. Based on our results, an antagonistic relationship between the inorganic turbidity and inorganic nutrients exists in the reservoir, the former modulating effects of the latter and thus limiting the potential for algal blooms. Should suspended sediment be removed without addressing nutrients at the same time, algal biomass is expected to increase dramatically. Likewise, high levels of dissolved inorganic nutrients, together with limited competition from the planktonic algae create an ideal set of conditions for floating macrophyte mats to develop.

In 2002 and 2006, we conducted a survey of historical collection localities for Enneacanthus chaetodon (Blackbanded Sunfish) in Maryland. Blackbanded Sunfish were detected at only one of six historical localities. This locality consisted of 17 quarry ponds, but the Blackbanded Sunfish was collected in only three of these. These ponds were characterized by low pH (<4.9), dense submerged and overhanging vegetation, and the absence or low abundance of non-native piscivores. The acidic nature of these ponds may provide refuge from predation for Blackbanded Sunfish by limiting numbers of non-native piscivores such as Micropterus salmoides (Largemouth Bass) and Pomoxis nigromaculatus (Black Crappie). As a result of the surveys described herein, the Blackbanded Sunfish state status in Maryland was elevated from Threatened to Endangered.

Point-count surveys targeting Ixobrychus exilis (Least Bittern), Laterallus jamaicensis (Black Rail), Rallus longirostris (Clapper Rail), Rallus elegans (King Rail), Porphyrio martinica (Purple Gallinule), and Gallinula chloropus (Common Moorhen) were performed using a standardized marsh-bird monitoring protocol along tidally influenced emergent marshes of coastal Alabama during the 2004 breeding season. We compared the number of target species detected during an initial passive-listening period to those detected during a subsequent multiple-species call-broadcast period to evaluate the effectiveness of the call-broadcast period for increasing detections. Additionally, we examined the number of responses of each target species to conspecific and heterospecific calls to determine how marsh birds respond to multiple species call-broadcast sequences. Numbers of new individuals detected during call-broadcast periods were significantly greater (P < 0.05) than those detected during the initial passive-listening period for Clapper Rail, King Rail, and Purple Gallinule, but not for Least Bittern and Common Moorhen. Black Rails were not detected during this study. Conspecific calls were more effective at eliciting responses than heterospecific calls for each of the target species except Least Bittern. Although the calls of Clapper Rail and King Rail are very similar, our data indicate that the advertisement calls of both species should be incorporated within multiple species call-broadcast sequences where populations are sympatric. We also recommend that Purple Gallinule call-broadcasts be applied to marsh-bird inventories or monitoring programs throughout this species' range as a result of its effectiveness, which was previously uncertain.

Baccharis halimifolia (Eastern Baccharis, Silverling, Groundsel-bush, or Salt-bush) (Asteraceae), a weedy shrub native to the US Gulf and Atlantic Coastal Plains, is believed to be expanding its distribution throughout much of its native range and in other regions of the globe to which it has been introduced (e.g., Australia and Mediterranean Europe). The present survey represents an effort to document the current distribution of this species across a portion of its apparent interior range limit in the south-central United States and to record habitat associations of B. halimifolia within this region. Data support previous research suggesting that B. halimifolia associates with various forms of canopy-removing anthropogenic disturbance, and that the limit of this species' present distribution in the mid-South lies primarily along the southern half of counties in Tennessee. However, habitat associations did not appear to vary across the study area, suggesting potential for further expansion into human-altered habitats throughout Tennessee and possibly further northward.

In stream ecosystems, bryophytes greatly increase substrate heterogeneity and support a high density and diversity of lotic primary producers, such as epiphytic algae. However, there is little information about how the spatial distribution and density of epiphytic diatoms varies with respect to bryophyte morphology. This study examined epiphytic diatom communities from the contrasting bryophyte morphologies of mosses and liverworts. We predicted that mosses, with morphologies that create more crevices, would have a higher density of epiphytic diatoms than liverworts, with leaves highly exposed to the turbulence of the stream current. Six species of bryophytes (two mosses and four liverworts) were collected from streams in the Great Smoky Mountains National Park, and 37 species of epiphytic diatoms were identified on these bryophytes. Diatom density was significantly higher on the adaxial leaf surface of mosses compared to the abaxial leaf area (ANOVA, df = 29, P < 0.001). There was no difference in diatom density on either the adaxial or abaxial leaf surfaces of liverworts, and these diatom densities were statistically identical to the density observed on the abaxial surface of moss leaves. The findings of our study support our hypothesis that the morphology of mosses, comprised of leafy whorls, provides a greater level of protection from disturbance than the open, flat nature of leafy liverworts. These findings emphasize that differences in microscale habitats can result in varying diatom distribution and density that may be critical to food-web interactions, such as grazing.

During the period of 1998 to 2004, surveys for dictyostelids (cellular slime molds) and myxomycetes (plasmodial slime molds or myxogastrids) were carried out at numerous study sites throughout the Great Smoky Mountains National Park as one component of the All Taxa Biodiversity Inventory (ATBI) project. As a result of these surveys, some general patterns have emerged relating to the occurrence and distribution of these two groups of organisms in the Park. Since the surveys began, the number of dictyostelids known from the Park has increased from 12 to at least 30, the highest total known for any comparable region outside of the tropics. Ten of the 30 species were described as new to science from material collected in the Park. Many of these are “small” species (<2 mm total height) that seem to be confined to marginal habitats at high elevations. The number of myxomycetes known from the Park has increased from 88 to approximately 220, but there are likely to be many additional records as the surveys continue. A number of myxomycetes appear to be restricted largely or exclusively to the Picea rubens (Red Spruce)—Abies fraseri (Fraser Fir) forests found at the very highest elevations in the Park. These forests are currently under considerable environmental stress as the result of industrial pollution and possible global climate change.

Field observations indicate an invasion by the non-native, Asian earthworm species Amynthas agrestis (Goto and Hatai 1899) in the Great Smoky Mountains National Park (GSMNP). The aim of this study was to determine if A. agrestis was capable of surviving in the ridge-top soil along an invasion front in a mesic—xeric habitat gradient in GSMNP. Additionally, this study sought to determine optimum and tolerance conditions for A. agrestis within a range of soil moistures and temperatures. Investigating soil temperature and moisture as parameters of earthworm survivability will allow for more predictive power when investigating the GSNMP invasion. Although A. agrestis invasions are widespread in eastern North America, few studies have addressed factors that may influence their distribution and their potential impacts on ecosystem processes. Using incubators and PVC tube microcosms, it was determined that A. agrestis was able to survive in the GSMNP ridge-top soil at temperatures of 12 °C and 25 °C. No survival was observed at temperatures of-5, 5, or 35 °C at any soil moisture level. No survival occurred in 25 °C dry (8% gravimetric water) treatments. Of the conditions tested, maximum survival plus fresh-weight maintenace occured at 12 °C and mid-moisture (24% gravimetric water), but highest activity and effects on litter and soil structure occurred at 25 °C and high soil moisture (57% gravimetric water; field capacity). Soil moisture contributed to the success of A. agrestis at higher temperatures within the tolerance conditions; more moisture increased the survival rate and decreased weight-loss.

We studied the wet-season food habits of adult Terrapene carolina bauri (Florida Box Turtles) on National Key Deer Wildlife Refuge, Big Pine Key, FL. Feces were collected from 112 Box Turtles (64 females, 48 males) and analyzed to determine diet. Based on percent occurrence (number of samples in which a particular dietary item occurs divided by the sample size), terrestrial gastropods and fleshy fruits were the principal foods consumed. Lesser amounts of leafy vegetation were recovered, whereas insects and other invertebrates, vertebrates (most likely consumed as carrion), and fungi composed a minor portion of the diet. The occurrence of deer feces in a single scat constitutes the first report of coprophagy by box turtles. Our fecal analysis provided little evidence of dietary specialization by either sex, which is consistent with earlier descriptions of box turtles as generalist omnivores. Male Florida Box Turtles were significantly larger than females, but there was no indication that larger body size in males provides access to an expanded resource base; the near-complete dietary overlap between the sexes suggests they consume the same foods.

In southern Louisiana, high population densities of exotic Myocastor coypus (Nutria) have been implicated in causing significant coastal marsh damage through extensive herbivory. Wildlife officials instituted a Nutria removal program in 2002 to reduce this marsh loss. Because Alligator mississippiensis (American Alligator) frequently consume Nutria, concern arose regarding the program's impacts on alligator food habits. Therefore, we conducted our study to determine if the Nutria removal program affected the frequency of occurrence of Nutria remains in alligator stomachs collected from five parishes in southern Louisiana. Three parishes had high Nutria densities and removal programs; two parishes had low Nutria densities and no Nutria removal. We collected >550 alligator stomachs during three September trapping seasons and examined the contents of each. We used logistic regression to model effects of year (1 year prior to the removal program compared to two years during removal) and parish (three with Nutria removal programs compared to two without) on the probability that an alligator stomach contained Nutria remains. Overall, about one-third of the alligator stomachs contained Nutria remains. Nutria removal appeared to have no effect on the probability of a stomach containing Nutria remains even after two years of Nutria removal. In addition, the probability that an alligator stomach contained Nutria remains was similar among all parishes regardless of whether Nutria removal occurred or not. We recommend that continuance of the Nutria removal program be based on its effectiveness in reducing marsh damage and not on perceived impacts to alligator food habits.

Myotis septentrionalis (Northern Long-eared Bat) is a small, insectivorous bat found in the eastern United States and Canada. Along the east coast, its range is thought to extend as far south as the Great Dismal Swamp in coastal Virginia. We captured six M. septentrionalis in the northern coastal plain region of North Carolina. Field identification was based on characters of ear and tragus length and confirmed with mitochondrial cytochrome c oxidase subunit I sequences. These captures signify the presence of a resident population of M. septentrionalis in the northern coastal plain of North Carolina. Future work is needed to document range limits and hibernation behavior of this species in the piedmont and coastal plain of North Carolina.

We examined site characteristics and prey abundances where wintering Aythya affinis (Lesser Scaup; hereafter scaup) foraged within three regions of the Indian River Lagoon system in central Florida. We observed that scaup concentrated in the Indian and Banana rivers; however, density of prey items did not differ between foraging sites and random sites. We also found that site characteristics were similar between foraging and random sites. Differences in site characteristics between random points across all three regions did not explain the distribution of foraging scaup (no scaup foraged in the Mosquito Lagoon); however, prey densities were approximately 3 times lower in the Mosquito Lagoon region. Our study suggests that current habitat conditions within the northern Indian River Lagoon system meet the overwintering requirements of scaup; however, prey densities in the Mosquito Lagoon may have been too low to be profitable for foraging scaup during the period of our study.