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USGS2009

Site characteristics and prey abundance at foraging sites used by Lesser Scaup ( Aythya affinis ) wintering in Florida

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.

Florida↗

USGS2011

Population densities of painted buntings in the southeastern United States

The eastern population trend of Passerina ciris (Painted Bunting) declined 3.5% annually during the first 30 yrs of the Breeding Bird Survey (BBS, 1966–1996). Recently, the US Fish and Wildlife Service listed Painted Buntings as a focal species. Surveys for this focal species for the next 10 yrs (BBS, 1997–2007), however, are too low (<1 bird per 50 stops) for determining trend estimates. Also, to monitor densities adequately, surveys should account for incomplete detections. I surveyed singing Painted Buntings from 13 May to 26 June 2003 at 582 point counts (50 randomly selected transects) within blocks (64 × 64 km) in coastal and river areas from Florida to North Carolina. I compared densities of Painted Buntings for major habitats. Painted Buntings were detected at 33.5% of points surveyed for 5 min. Densities varied from 9 singing males per km 2 in young pine plantations to 42 per km 2 in maritime shrub. Effective detection radii for habitats varied from 64 to 90 m and were slightly higher in developed than in undeveloped habitats. Distance sampling is recommended to determine densities of Painted Buntings; however, large sample sizes (70–100 detections/habitat type) are required to monitor Painted Bunting densities in most habitats in the Atlantic coastal region of the southeastern United States. Special attention should be given to maritime shrub habitats, which may be important to maintaining the Painted Bunting population in the southeastern US.

Florida, Georgia, North Carolina, South Carolina↗

USGS2006

Survey and monitoring of species at risk at Camp Blanding Training Site, northeastern Florida

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.

Southeastern Naturalist↗

USGS2005

Further evidence for the invasion and establishment of Pterois volitans (Teleostei: Scorpaenidae) along the Atlantic Coast of the United States

We document the continued population expansion of red lionfish, Pterois volitans, the first documented successful introduction of an invasive marine fish species from the western Pacific to Atlantic coastal waters of the United States. Red lionfish are indigenous to the Indo-Pacific and have apparently established one or more breeding populations on reefs off the southeastern United States. Fifty-nine specimens, most presumably adult red lionfish, were documented or collected on live-bottom reefs off North Carolina, South Carolina, and Florida, and on a manmade structure off Georgia. Observation/collection depths and bottom water temperatures for these fish ranged from 40-99 m and 13.8-24.4??C, respectively. Eleven juvenile lionfish, believed to be expatriated from southeastern waters, were collected in estuaries along the coast of Long Island, NY, at depths of 0-5 m and water temperatures ranging from 13.8-16.5??C. Twelve of the total 70 specimens collected or observed were positively identified as red lionfish. Based on histological assessment of gonad tissue, two reproductively-active males and one immature female were collected. The life history of red lionfish, especially their reproductive biology and food habits, should be investigated along the east coast of the US to determine the potential impacts of this species on ecosystems they have invaded.

Southeastern Naturalist↗

USGS2024

Using camera traps to estimate site occupancy of invasive Argentine Black and White Tegus (Salvator merianae) in South Florida

The introduction of nonnative species is a leading cause of biodiversity loss. Many invasive species are cryptic or elusive in nature and therefore often evade detection, complicating their management. Occupancy modeling can reveal the presence and spread of invasive species over time and therefore has important management implications. Camera traps can be used to estimate occupancy, or the proportion of sites that are occupied by a target species. During a 4-year study (2016–2020), we used camera traps both with and without lures to detect the presence of invasive Salvator merianae (Argentine Black and White Tegu) at sites in Miami-Dade County, FL. Our results from a multi-season occupancy model revealed that a quadratic effect of ordinal day was the best predictor of detection, with a peak in June, while occupancy was correlated with distance to landscape features that may facilitate tegu movement. We did not detect any large-scale changes in occupancy over the course of our study. We also discovered that the use of lures with camera traps did not impact detection, indicating fewer resources would be required from invasive species managers for effective monitoring. Understanding the factors that impact occupancy and detection probabilities can inform surveillance and removal efforts, leading to more efficient management strategies.

Florida↗

USGS2002

Taxonomic assessment of the black bear (Ursus americanus) in the eastern United States

The subspecific status of the Louisiana black bear ( Ursus americanus luteolus ) and Florida black bear ( U. a. floridanus ) were assessed using morphologic features to determine their distinctness in relation to one another and to the black bear ( U. a. americanus ). Forty-four dimensions were recorded from skulls of 125 male and 127 female adult (4.5 years or older) bears. Results showed skulls of U. a. luteolus, U. a. floridanus , and U. a. americanus to be similar in morphology. However, features of U. a. luteolus , and U. a. floridanus tended, in general, to be larger and shaped differently than those of U. a. americanus . Differences between measurements of U. a. luteolus and U. a. floridanus were less apparent than those between either of these taxa and U. a. americanus . For U. a. luteolus and U. a. floridanus , means of most characters differed only slightly, and ranges of all measurements overlapped to some degree. Yet, small numbers of characters that reflected molar tooth measurements or features relating to dentition, height of frontal region, and skull length and width appeared to correctly classify these taxa in most cases. Results were interpreted to support the subspecific recognition of U. a. luteolus, U. a. floridanus , and U. a. americanus .

Southwestern Naturalist↗

USGS2009

Vegetation effects on fish distribution in impounded salt marshes

We compared the density and biomass of resident fish in vegetated and unvegetated flooded habitats of impounded salt marshes in the northern Indian River Lagoon (IRL) Estuary of east-central Florida. A 1 -m 2 throw trap was used to sample fish in randomly located, paired sample plots ( n = 198 pairs) over 5 seasons in 7 impoundments. We collected a total of 15 fish taxa, and 88% of the fishes we identified from the samples belonged to three species: Cyprinodon variegatus (Sheepshead Minnow), Gambusia holbrooki (Eastern Mosquitofish), and Poecilia latipinna (Sailfin Molly). Vegetated habitat usually had higher density and biomass of fish. Mean fish density (and 95% confidence interval) for vegetated and unvegetated sites were 8.2 (6.7–9.9) and 2.0 (1.6–2.4) individuals m -2 , respectively; mean biomass (and 95%) confidence interval) for vegetated and unvegetated sites were 3.0 (2.5–3.7) and 1.1 (0.9–1.4) g m -2 , respectively. We confirmed previous findings that impounded salt marshes of the northern IRL Estuary produce a high standing stock of resident fishes. Seasonal patterns of abundance were consistent with fish moving between vegetated and unvegetated habitat as water levels changed in the estuary. Differences in density, mean size, and species composition of resident fishes between vegetated and unvegetated habitats have important implications for movement of biomass and nutrients out of salt marsh by piscivores (e.g., wading birds and fishes) via a trophic relay.

Florida↗

USGS2002

Life history of the striped newt at a north-central Florida breeding pond

I studied the life history of Striped Newts (Notophthalmus perstriatus) at a breeding pond in north-central Florida. Newts were captured in pitfall traps at a drift-fence as they migrated into and out of the pond basin. During the 2-year study, I recorded 10,290 captures (8,127 individuals) of newts at the drift-fence. Newts were active during each month of the study, but there were four peak activity periods, each of which included immigration and emigration events. Immigration events were almost exclusively comprised of adults, whereas emigration events were comprised of adults and recently transformed larvae. I documented 5,296 recently transformed, immature larvae (efts) and 435 recently transformed mature larvae (paedomorphs) during four distinct periods of emigration. Efts matured in the uplands before returning to the pond to breed. In the uplands, male efts (n = 16) grew 0.0183 mm/day on average, whereas average female (n = 24) growth was 0.0167 mm/day. Immigrating adults of both sexes were significantly smaller than emigrating adults. Emigrating efts were smallest, followed by emigrating paedomorphs, immigrating adults, then emigrating adults. The overall adult sex ratio was 1:1.25 (m:f). Sex ratio of emigrating paedomorphs was highly skewed towards females, with one male for every 4.43 females. Newts tended to move during wetter periods, and captures were significantly correlated with rainfall, but rainfall was a poor predictor of the magnitude of newt movements.

Southeastern Naturalist↗

USGS2017

New distributional records of the stygobitic crayfish Cambarus cryptodytes (Decapoda: Cambaridae) in the Floridan Aquifer System of southwestern Georgia

Cambarus cryptodytes (Dougherty Plain Cave Crayfish) is an obligate inhabitant of groundwater habitats (i.e., a stygobiont) with troglomorphic adaptations in the Floridan aquifer system of southwestern Georgia and adjacent Florida panhandle, particularly in the Dougherty Plain and Marianna Lowlands. Documented occurrences of Dougherty Plain Cave Crayfish are spatially distributed as 2 primary clusters separated by a region where few caves and springs have been documented; however, the paucity of humanly accessible karst features in this intermediate region has inhibited investigation of the species' distribution. To work around this constraint, we employed bottle traps to sample for Dougherty Plain Cave Crayfish and other groundwater fauna in 18 groundwater-monitoring wells that access the Floridan aquifer system in 10 counties in southwestern Georgia. We captured 32 Dougherty Plain Cave Crayfish in 9 wells in 8 counties between September 2014 and August 2015. We detected crayfish at depths ranging from 17.9 m to 40.6 m, and established new county records for Early, Miller, Mitchell, and Seminole counties in Georgia, increasing the number of occurrences in Georgia from 8 to 17 sites. In addition, a new US Geological Survey (USGS) Hydrologic Unit Code 8 (HUC8) watershed record was established for the Spring Creek watershed. These new records fill in the distribution gap between the 2 previously known clusters in Georgia and Jackson County, FL. Furthermore, this study demonstrates that deployment of bottle traps in groundwater-monitoring wells can be an effective approach to presence—absence surveys of stygobionts, especially in areas where surface access to groundwater is limited.

Geogia↗

USGS2020

Evidence for an established population of tegu lizards Salvator merianae in southeastern Georgia, USA

Documenting emergence of invasive species in new areas is vital to understanding spatiotemporal patterns of invasions, propagule pressure, and the risk of establishment. Salvator merianae (Argentine Giant Tegu) has established multiple unconnected populations in southern and Central Florida, and additional sightings have been reported elsewhere in the state. In 2018, land managers in Georgia received >20 reports of this species in the wild. To evaluate the probability of establishment, we assembled verified records of the non-native Argentine Giant Tegu in Georgia over the past nine years. We report on 47 tegu observations throughout Georgia, with a concentration of sightings (n = 38) in Toombs and Tattnall counties. In 2019, we used modified Havahart traps and captured adult male and female tegus at one of our three locations during 3085 corrected trap nights. While we did not find evidence of a well-established population (i.e., varied size structure of tegus captured) with our limited trapping effort, we suspect tegus are breeding in Toombs and Tattnall counties due to the concentration of captures and reports of adult males and females, the consistent reports of adults across years, the confirmed presence of tegus in 2018, 2019 and 2020, and the reproductive capacity (i.e., turgid testes and secondary follicles) of tegus captured. Ongoing tegu introductions from captivity are likely to maintain high propagule pressure in the southeastern United States. Effective early detection, funded rapid response networks, and public outreach to solicit reports of tegu sightings are critical to prevent establishment and associated ecological impacts of this invasive species elsewhere in the southeastern US.

Southeastern Naturalist↗

USGS2013

Diet of the eastern mudminnow (Umbra pygmaea DeKay) from two geographically distinct populations within the North American native range

Umbra pygmaea (Eastern Mudminnow) is a freshwater species common in Atlantic slope coastal lowlands from southern New York to northern Florida and is typical of slow-moving, mud-bottomed, and highly vegetated streams, swamps, and small ponds. We examined its seasonal food habits at the Great Swamp National Wildlife Refuge (NWR), NJ and at the Croatan National Forest, NC. A total of 147 Eastern Mudminnow from 35–112 mm TL and 190 Eastern Mudminnow from 22–89 mm TL were examined from these sites, respectively. At both locations, we found it to be a bottom-feeding generalist that consumes cladocerans, ostracods, chironomid larvae, coleopteran larvae, and other insects and crustaceans. Ostracods were most common in the diet at the Great Swamp NWR and occurred in 62% ± 2.5% of the stomachs with food. At Croatan National Forest, chironomid larvae were most common and occurred in 66.7% ± 15.8% of the stomachs. There were no statistically significant differences in diet composition between the sites during the winter, summer, and fall. However, when compared on an annual basis, Jaccard’s Index (θ J = 0.636, P = 0.05) suggested that the diet at the two study sites was significantly different. While we identified the same major food groups at both locations, the utilization of these food groups varied seasonally. Detritus was a major stomach content at both locations throughout the year. We also documented cannibalism during the summer season at both locations. The seasonal diet of the Eastern Mudminnow was similar to that of Umbra limi (Central Mudminnow) and Umbra krameri (European Mudminnow). Our findings here are the first quantitative examinations of seasonal differences in the diet of the Eastern Mudminnow within its native North American range.

Northeastern Naturalist↗