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Periodic quantitative surveys to monitor populations of freshwater mussels (Unionidae) were conducted at eight sites in the Verdigris River, KS during 1991, 1997, and 2003. Twenty-two species were collected including several on the Kansas rare-species list. Overall mussel abundance increased from 1991–2003. Abundance of 10 species (Cyprogenia aberti, Fusconaia flava, Lasmigona complanata, Pleurobema sintoxia, Ptychobranchus occidentalis, Quadrula metanevra, Quadrula nodulata, Quadrula pustulosa, Tritogonia verrucosa, and Truncilla donaciformis) increased significantly while only Lampsilis teres decreased. This positive trend in unionid abundance could be due to various factors that have improved habitat quality of this reach of river.
We examined relationships between catchment-scale disturbance from military training and two dominant fish species, Pteronotropis euryzonus (broadstripe shiner) and Semotilus thoreauianus (Dixie chub) in headwater streams at the Fort Benning Military Installation (FBMI), GA. Disturbance was estimated as the percent of the catchment that was bare ground and unpaved road cover. Relative abundance of broadstripe shiners and Dixie chubs were negatively and positively related to disturbance, respectively. This complementarity likely resulted from contrasting life histories, feeding behaviors, and habitat preferences between the two species. Absolute abundance of broadstripe shiners increased, whereas relative abundance of Dixie chubs decreased, with stream discharge, suggesting that both species were affected by local habitat conditions. Additionally, the average body size of both species was lower in high-disturbance streams, signifying that both species were affected by disturbance. Results also suggest a disturbance threshold, where streams with disturbance levels of ≈ 5–8.1% of the catchment had broadstripe shiner proportions below those in low-disturbance streams. About 71–88% of second-order catchments on FBMI lie below this threshold level, suggesting that many streams on FBMI are potentially suitable for the broadstripe shiner.
Etheostoma scotti (Cherokee darter) is a member of the subgenus Ulocentra and a federally threatened endemic to the Etowah River system, GA. Field observations of spawning behavior of the Cherokee darter were made at five stream sites to identify spawning season and habitat over two field seasons. Cherokee darters primarily spawn in pool habitats between mid-March and early June, at temperatures between 11 and 18 °C. Egg deposition was typically on large gravel substrate, but ranged from gravel to bedrock in size and included woody debris. Spawning occurred in a variety of depths (0.09–0.59 m) and velocities (0–0.68 m/s).
We examined the relationship between seven wall-microhabitat features and the occurrence of the nonindigenous Hemidactylus turcicus (Mediterranean Gecko) in north-central Florida using a repeatable technique. We characterized 160 one-story walls by age of the building, cardinal orientation, color, length, presence or absence of a light source, building material, and vegetation level, and recorded the presence or absence of H. turcicus for each wall during two separate nocturnal visits. The occurrence of H. turcicus was only dependent on wall surface color and length. Both the lack of significance of the majority of the microhabitat variables investigated and the fact that H. turcicus was found on all wall types suggest that this gecko is capable of inhabiting a wide variety of wall environments. This habitat flexibility may be a key factor in the prolific expansion of this gecko's nonnative range.
Monthly surveys were conducted in Gregorys Cave, Great Smoky Mountains National Park, for one year using systematic, repeatable methods to quantify the distribution and abundance of the salamanders Eurycea longicauda and Plethodon glutinosus. Information was gathered regarding larval development of E. longicauda in cave pools, as well as the occurrence of young P. glutinosus. Salamanders were most commonly encountered during spring and late summer from the entrance gate to 50 m inside the cave. Both species were found deepest in the cave during late summer–early fall and late winter–early spring. Young P. glutinosus and recently transformed E. longicauda were observed during late winter and early spring between 50 and 80 m inside the cave. Additional study is required to further understand the timing and frequency of metamorphosis of larval E. longicauda in cave pools.
Food habits of 109 Macrochelys temminckii (Alligator Snapping Turtles) collected from Arkansas and Louisiana were studied by examination of stomach and intestinal tract contents from harvested turtles. There was a positive correlation between the turtle carcass mass and the gastrointestinal tract content mass (r = 0.39106, p < 0.0001). The most commonly occurring prey item was fish, followed by Procambarus clarkii (crawfish), molluscs, turtles, insects, and Myocastor coypus (nutria). Other mammalian species occurred infrequently, as did snakes, birds, and crabs. Several species (Dasypus novemcinctus [armadillo], Didelphis virginiana [opossum], Sciurus sp. [squirrel], and Sus scrofa [hogs]) that have not previously been reported as prey items for Alligator Snapping Turtles were noted. Some prey items were recovered in intestinal tracts that were not observed in stomachs, illustrating the importance of examination of the entire gastrointestinal tract when evaluating food habits in this species. The results suggest Alligator Snapping Turtles are opportunistic scavengers able to consume a wide variety of prey species.
We analyzed a 15-year (1989–2003) dataset of spatial nesting locations for Loggerhead and Green Turtles along a 40.5-km stretch of beach encompassing the Archie Carr National Wildlife Refuge along the Atlantic coast of Florida. To assess whether there are differences in spatial distribution influenced by temporal site-selection cues, we divided each season into quartiles and analyzed the autocorrelative patterns of the nest distributions within each time frame. Fundamentally, intraspecific differences in nest spatial patterns from the beginning to the end of the nesting season were minor. Though the temporal grain of the analyses may not be able to discern affects of fine-scale fluctuations (e.g., high- and low-tide events), these results suggest that environmental variables that change over the nesting season (e.g., ocean temperatures, daylength, and existing human activities) are not significantly influencing where these sea turtles place their nests.
Extensive trapping surveys across the historical range of Pituophis ruthveni (Louisiana Pine Snake) suggest that extant populations are extremely small and limited to remnant patches of suitable habitat in a highly fragmented landscape. Evaluation of habitat at all known historical localities of P. ruthveni documents the widespread degradation of the fire-maintained pine ecosystem throughout the historical range of the species. The primary factors leading to degradation of P. ruthveni habitat are intensive pine silviculture and alteration of the pre-European fire regime. Habitat restoration on public lands is feasible and could potentially restore populations of this critically rare species.
We studied the presence and distribution of 19 species at risk in northeastern Florida at the Camp Blanding Training Site (CBTS) during 2000–2001, seven years after the first major baseline surveys of CBTS were conducted. Much of the training conducted at CBTS deals with light infantry exercises, but the site is also used for mining, silviculture, hunting, fishing, emergency logistical support, and entertainment purposes. CBTS contains more than 2000 species of plants and animals in 14 natural communities, each impacted to various degrees by past and current land management. Adaptive management plans for species may be ineffective without continual feedback and the flexibility for change. Here we summarize and discuss the results of our surveys, compare these results with those of past surveys, identify differences between the surveys, and discuss the importance of systematic protocols and study design for CBTS environmental managers.
I conducted a vegetative survey of the wetland habitats at Jean Lafitte National Historical Park and Preserve (JLNHPP) - Barataria Unit. Although wetland habitats make up over 65% of the total park area, there has never been a thorough vegetative survey of this portion of the preserve. Three main habitats were identified: freshwater floating marsh, spoil banks, and waterways. The floating-marsh habitat was further divided into three different community types: thick mat, thin mat, and wax-myrtle thicket. The thick-mat community encompasses four vegetative associations characterized by their dominant species. These are the Sagittaria lancifolia, Typha spp., Schoenoplectus americanus, and Spartina spp. associations. Overall, I identified 168 species in 113 genera in 60 families. Of these, 47 species had never been recorded in the area now encompassed by JLNHPP, and 27 species had not previously been recorded in Jefferson Parish, LA. The three most prevalent families were Cyperaceae (29 species), Poaceae (24 species) and Asteraceae (16 species).
Helenium virginicum (Virginia sneezeweed) is a federally listed threatened herb found at unshaded sites in seasonally inundated ponds in the Shenandoah Valley of Virginia and in the Ozark Highlands of Missouri. In the Ozarks, one population of H. virginicum was discovered in the 1950s, though it was thought to be a hybrid of Helenium flexuosum and Helenium autumnale until genetics work resolved its identity in 2000. Since that time, it was the only known population outside of Virginia. In this study, we systematically identified potential H. virginicum habitat in the Ozarks by using topographic maps and aerial photographs and surveyed these areas for H. virginicum. Our objectives were to locate new populations of the plant and to better define its ecology in Missouri. By the end of the growing season of 2004, we had located 42 new populations of H. virginicum in the lower Missouri Ozarks—more populations than are currently known in the state of Virginia. The results of this study greatly expand the known range of H. virginicum in Missouri and provide important information regarding its ecology.
The recent invasion of Dasypus novemcinctus (nine-banded armadillo) into the southeastern United States has brought it into contact with a native burrowing chelonian, Gopherus polyphemus (Gopher Tortoise), whose burrows it usurps. Because the Gopher Tortoise is listed as vulnerable by IUCN (1996), baseline data on burrows of armadillos might improve our understanding of the impact of this introduced mammal on this reptile. Armadillo burrows were counted in a stratified random sample of 4 major habitats at Avon Park Air Force Range, FL. Data on spatial distributions of the burrows in all habitats fit the negative binomial distribution, indicating clumping. Burrow density in pine habitats was more than twice that of oak hammock, sand pine, or oak scrub. Likelihood-ratio tests combined with Akaike's Information Criteria showed that the best model was one in which the dispersion parameter (k) did not vary but the parameter for the arithmetic mean (m) did.
Based on microhistological examinations of feces, Cervus elaphus (elk) from a reintroduced herd on the Cumberland Plateau in southeastern Kentucky exhibited an annual diet of grasses (24%), forbs (27%), and browse (32%). Diets shifted seasonally, possibly in response to availability and palatability. Forbs dominated the summer diet (34%), whereas grasses, forbs, and woody browse accounted for approximately equal portions of the fall diet. Grasses (40%), and browse (46%) dominated the diet during winter and spring, respectively. Grasses were eaten less during spring (10%) than during any other month. Nutritional quality does not appear to be limiting in this growing population.
We studied the breeding biology of two Agelaius phoeniceus (Red-winged Blackbird) populations in south Florida. Red-winged Blackbirds in our study bred at low relative abundance in a wide variety of habitats, were rarely socially polygynous, and were highly aggressive toward intruders. The breeding season extended from March through August and coincided with the rainy season. Nesting periods were similar to those reported for other subspecies of Red-winged Blackbirds, but clutch sizes were small, with 2- and 3-egg clutches predominating. Nesting success varied from 28% on Sanibel Island to 63% on the Florida Keys. Both populations accepted a majority of artificial eggs into their nests, although cowbird parasitism has been rarely reported in south Florida.
Broadcast vocalizations have been used to augment winter point counts. We investigated the effects of time and Strix varia (Barred Owl) playback on woodpecker detection. Habitats were classified as upland pine, bottomland hardwood, and mixed pine-hardwood stands. Ten unlimited-radius, silent point counts of 3-min and 10-min duration were conducted in each habitat type on alternating weeks. During alternate weeks, silent counts followed by Barred Owl playback and post-playback counts were conducted. Detection was significantly greater during 10-min silent counts than during 3-min silent counts. We detected more woodpeckers after Barred Owl playback than during 3-min silent counts prior to playback. Species diversity was highest in mixed pine-hardwood stands, although abundance was lower than in hardwood stands. Mixed stands may not be able to support high woodpecker densities as well as bottomland hardwood forests.
A marked decline in the Picoides borealis (Red-cockaded Woodpecker [RCW]) population at Noxubee National Wildlife Refuge, MS, was observed in 2002. Demographic changes—including absence of hatch-year birds, decreases in size of known groups, and loss of known groups—were identified during annual fall surveys and are uncharacteristic of RCW populations. In 2003, a serosurvey of 28 adult RCWs was conducted to investigate the presence of West Nile virus (WNV) exposure in the population, possibly providing insight into whether WNV may have been responsible for this decline. Blood smears were also examined from these birds for blood parasites. We found no evidence of West Nile virus exposure or blood parasites in any of the RCWs sampled. Further monitoring of the RCW population and WNV activity in other species at Noxubee NWR is recommended to further evaluate the potential role of WNV and blood parasites in their decline.