118 research outputs found

    Temporal Trends in Florida Panther Food Habits

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    Once on the brink of extinction, the Florida panther (Puma concolor coryi) has reoccupied parts of its extirpated range in southern Florida, USA over the past 20 years, which has largely been attributed to genetic restoration efforts initiated in 1995 to combat inbreeding depression and subsequent deleterious traits. Concurrent to the resurgence, an increase in documented livestock depredation events has heightened concern over human– panther conflicts. We examined 312 stomach content, scat, and feces (large intestine contents) samples collected 1989 to 2014 across the endemic range in southern Florida. We compared frequency of occurrence of prey items in samples by temporal (pre- and post-genetic restoration), geographic (north and south of 26° 10.017′ latitude), and demographic (age and sex) categories. We observed an apparent temporal shift in prey item occurrence in scats, where raccoon (Procyon lotor) occurrence increased while wild hog (Sus scrofa) occurrence decreased, whereas white-tailed deer (Odocoileus virginianus) occurrence appeared constant. Post-genetic restoration, we observed a geographic difference in panther prey, where white-tailed deer and raccoons were consumed more commonly in the southern part of the study area (characterized by lower soil quality and higher hydrological fluctuations), while wild hogs were consumed more frequently in the northern part of the study area. Neither sex nor age appeared to affect frequency of prey occurrence. Pets and livestock were not frequently found in the samples we examined. Overall, our results show shifts in panther diets both temporally and geographically; however, no notable changes in frequency of livestock found in panther diets were observed

    Habitat Selection by Critically Endangered Florida Panthers across the Diel Period: Implications for Land Management and Conservation

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    Decisions regarding landscape management, restoration, and land acquisition typically depend on land managers’ interpretation of how wildlife selects habitat. Such assessments are particularly important for umbrella species like the endangered Florida panther (Puma concolor coryi), whose survival requires vast wildlands. Some interpretations of habitat selection by panthers have been criticized for using only morning locations in defining habitat use. We assessed habitat selection using a Euclidean distance analysis (EDA) and location data collected throughout the diel period from GPS collars deployed on 20 independent Florida panthers. We corroborated aspects of earlier analyses by demonstrating selection of forested habitats by panthers. We also confirmed selection of open habitats (i.e., marsh–shrub–swamps, prairie–grasslands), a novel result. Habitat selection did not vary by sex or season but varied by time of day. Panthers were located closer to wetland forests in the daytime and used prairie–grasslands more at night. Our assessment of the effect of patch size on selection of forest habitat revealed that panthers were not solely reliant on large patches (\u3e 500 ha) but utilized patches of all sizes (≤ 1 ha, \u3e 5–10 ha, \u3e 1000 ha, etc.). Our results emphasize the importance of collecting panther location data throughout the diel period when assessing habitat selection. Conservation strategies for panthers should consider a mosaic of habitats, a methodology that will protect other sensitive flora and fauna in South Florida

    Parasite Component Community of Smalltooth Sawfish Off Florida: Diversity, Conservation Concerns, and Research Applications

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    Compared with that of other charismatic elasmobranchs, the component community of metazoan parasites infecting endangered smalltooth sawfish Pristis pectinata is exceedingly poorly characterized: adults of Dermophthirioides pristidis and Neoheterocotyle inpristi (ectoparasitic flatworms of skin and gill, respectively) were the only confirmed parasites prior to the description, based on specimens reported herein, of Mycteronastes caalusi. Our opportune and directed parasitological examinations of 290 smalltooth sawfish (277 live inspections; 13 necropsies; 671 to 2640 mm stretch total length) in south Florida coastal waters revealed at least 8 species of Platyhelminthes, 9 of Arthropoda, 4 of Annelida, and 1 of Nematoda. This collection includes representatives of an undescribed species of Aporocotylidae (Digenea) and myriad new host records, considerably updating and advancing our understanding of smalltooth sawfish symbionts. We also confirm that D. pristidis and N. inpristi are extant and propose D. pristidis as a reliable biological tag. Some of these parasites are evidently highly host-specific and so vulnerable to extinction

    Systematic assessment of training-induced changes in corticospinal output to hand using frameless stereotaxic transcranial magnetic stimulation.

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    Measuring changes in the characteristics of corticospinal output has become a critical part of assessing the impact of motor experience on cortical organization in both the intact and injured human brain. In this protocol we describe a method for systematically assessing training-induced changes in corticospinal output that integrates volumetric anatomical MRI with transcranial magnetic stimulation (TMS). A TMS coil is sited to a target grid superimposed onto a 3D MRI of cortex using a stereotaxic neuronavigation system. Subjects are then required to exercise the first dorsal interosseus (FDI) muscle on two different tasks for a total of 30 min. The protocol allows for reliably and repeatedly detecting changes in corticospinal output to FDI muscle in response to brief periods of motor training

    Assessment of Maturity in the Eastern Gulf of Mexico Florida Stone Crab \u3cem\u3eMenippe mercenaria\u3c/em\u3e Fishery

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    The Florida stone crab Menippe mercenaria supports one of Florida\u27s most valuable commercial fisheries. Sustained fishing pressure and overexploitation, despite negative trends in landings, have facilitated the need to transition from stock assessments based on effort and landings toward more sophisticated methods. This requires accurate knowledge of life history parameters, such as size at sexual maturity. The physiological, behavioral, and functional maturity of female Florida stone crabs and the physiological maturity of male crabs were assessed in individuals collected throughout the geographically fished range of the population between 2013 and 2014. Morphological maturity of both sexes was assessed in individuals collected from the same locations in 2005–2016. Histology was used to determine oocyte maturity, presence of spermatophores, and presence of postovulatory follicles in females and the production of spermatophores (present in the anterior vas deferens) in males. Decision tree analysis determined that 50% of females were mature at 43 mm carapace width (CW) based on an indicator of physiological and behavioral sexual maturity. In males, physiological maturity occurred at a CW of 34.75 mm. Sexual maturity estimated using morphological maturity occurred at 66.3 mm CW in females and 63.1 mm CW in males. Differences in estimated size at sexual maturity between morphological maturity and physiological, behavioral, and functional maturity indicate that the relative growth of body parts is not reliable for estimating sexual maturity in Florida stone crabs. Smaller females may be contributing more to the spawning population than had been previously estimated. Large, morphometrically mature males may be more successful in mating encounters, but during times of flux in population size structure (i.e., fewer large males), morphologically immature but physiologically mature males have increased mating opportunities. Results indicate that male and female Florida stone crabs can contribute to the reproductive population multiple times before they become vulnerable to the fishery

    Dynamics of Stony Coral and Octocoral Juvenile Assemblages Following Disturbance on Patch Reefs of the Florida Reef Tract

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    In January 2010, reefs in the Upper and Middle Florida Keys experienced prolonged exposure to extremely cold water temperatures, below lethal thresholds for many reef organisms including corals. We examined post-disturbance juvenile assemblages of stony corals and octocorals on eight patch reefs, four of which were categorized as high impact and four as low impact, based on declines in stony-coral cover following disturbance. We established permanent quadrats to conduct field surveys in spring and fall of 2012 and 2013. Overall, juvenile abundances of both stony corals and octocorals were greater on low-impact sites, suggesting that those sites had higher recruitment and juvenile survival than high-impact sites. Juvenile assemblages also showed a regional pattern, with more stony corals on Middle Keys sites and more octocorals on Upper Keys sites. The stony-coral juvenile assemblage was dominated by Siderastrea siderea (46%) and Porites astreoides (19%), whereas previously abundant species such as Orbicella annularis were nearly absent (\u3c3%). Octocoral juveniles were dominated by Antillogorgia spp. (25%), Gorgonia spp. (21%), Eunicea spp. (19%) and Erythropodium caribaeorum (14%). Overall, post-disturbance juvenile assemblages displayed a wide range of octocoral genera, but only a few select stony-coral species, which exhibited either opportunistic or hardy life-history characteristics
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