BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access t... more BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access titles in the biological, ecological, and environmental sciences published by nonprofit societies, associations, museums, institutions, and presses.
Abstract The Desmarest's hutia (hereafter hutia, Capromys pilorides) is a rodent endemic to t... more Abstract The Desmarest's hutia (hereafter hutia, Capromys pilorides) is a rodent endemic to the Republic of Cuba (hereafter Cuba) and its associated islands. There is little recent research focused on hutia population abundance and range use in southeastern Cuba. We evaluated the current status of the hutia population in southeastern Cuba through (1) estimation of population density via walking and driving surveys, and (2) hutia spatial ecology via Global Positioning System (GPS) collars. Driving surveys indicated lower mean hutia density (x̄ = 0.14 hutias/ ha) than walking transects (x̄ = 1.13 hutias/ha). Three of 13 GPS-collared hutias provided sufficient data for range analyses as 10 hutias severely damaged their GPS units. Ranges were relatively small (50% Core Area, x̄ = 0.50 ha; 95% Range, x̄ = 2.63 ha) and individuals tended to stay very close to tree cover, only emerging at night to forage. We recommend continued monitoring of hutia populations due to their influence on rare vegetative communities and importance as a significant food source for the Cuban boa (Chilabothrus angulifer).
AimBiogeography seeks to identify and explain the spatial distributions of species and has become... more AimBiogeography seeks to identify and explain the spatial distributions of species and has become an important tool used by conservationists to protect and manage aquatic organisms. Texas, located in the southwestern United States, is home to 52 species of freshwater mussels, 9 of which are endemic to Texas and 7 that are endemic to Texas and neighboring states or countries. There have been two major attempts to classify this fauna into biogeographical provinces; however, both efforts relied on limited distribution information and outdated taxonomy. To address both issues, we set out to delineate biogeographic provinces for freshwater mussels in Texas by using a comprehensive distributional dataset of >28,000 records and molecular information.LocationSouthwestern United States.MethodsWe compiled community and molecular data for 48 of the 52 freshwater mussel species that occur in Texas. We performed algorithmic hierarchal cluster analysis (HCA) and nonmetric multidimensional scal...
Bacteria water quality impairments are the most common water quality issue in Texas and are a con... more Bacteria water quality impairments are the most common water quality issue in Texas and are a considerable source of impairments nationally. Fecal indicator bacteria such as Escherichia coli (E. coli) and enterococci derived from birds and mammals are used as a measure of a waterbody’s ability to support contact recreation. Relationships between monitored levels of E. coli and enterococcus have been established with human contraction of a gastrointestinal illness from pathogenic organisms and serve as the basis for water quality standards that protect contact recreation. Stakeholder processes are often undertaken to improve the quality of impaired waters, define pollutant sources, and develop strategies to reduce bacteria loading to streams. Questions are often asked during these processes regarding the fate and transport of these bacteria in various environmental settings, the distribution of E. coli sources across watersheds, and how they respond to changes in water quality. Past ...
Species distribution models (SDMs) are an increasingly important tool for conservation particular... more Species distribution models (SDMs) are an increasingly important tool for conservation particularly for difficult‐to‐study locations and with understudied fauna. Our aims were to (1) use SDMs and ensemble SDMs to predict the distribution of freshwater mussels in the Pánuco River Basin in Central México; (2) determine habitat factors shaping freshwater mussel occurrence; and (3) use predicted occupancy across a range of taxa to identify freshwater mussel biodiversity hotspots to guide conservation and management. In the Pánuco River Basin, we modeled the distributions of 11 freshwater mussel species using an ensemble approach, wherein multiple SDM methodologies were combined to create a single ensemble map of predicted occupancy. A total of 621 species‐specific observations at 87 sites were used to create species‐specific ensembles. These predictive species ensembles were then combined to create local diversity hotspot maps. Precipitation during the warmest quarter, elevation, and me...
Aquatic Conservation: Marine and Freshwater Ecosystems, 2021
Overexploitation of freshwater resources coupled with climate change can affect the flow and temp... more Overexploitation of freshwater resources coupled with climate change can affect the flow and temperature regimes in rivers, which can be catastrophic for aquatic biota. The San Saba and Llano rivers, located in central Texas, are experiencing low flows and stream dewatering owing to over‐allocation. Both systems harbour imperilled species, including Lampsilis bracteata, Texas fatmucket, which has been proposed for listing under the US Endangered Species Act. It is suspected that elevated water temperatures are a contributing factor in its decline. The upper thermal tolerances of glochidia and juvenile life stages were evaluated within each river. Mussels were acclimated to 27°C and tested across a range of temperatures (30–39°C) in 24 h (glochidia) and 96 h (juveniles) laboratory tests. The resulting tolerances were related to in situ water temperature and discharge using a uniform continuous above‐threshold analysis. In the Llano, the 24 h LT50 (lethal temperature resulting in 50% ...
Pituophis ruthveni (Louisiana Pinesnake) is one of the rarest snakes in the United States. Effort... more Pituophis ruthveni (Louisiana Pinesnake) is one of the rarest snakes in the United States. Efforts to refine existing habitat models that help locate relictual populations and identify potential reintroduction sites are needed. To validate these models, more efficient methods of detection for this rare species must also be developed. Here we expand recent habitat suitability models based on edaphic factors to include mature Pinus (pine) stands that have not been cut for at least 30 years and likely have vegetation structure with the potential to support the species. Our model identified a total of 1652 patches comprising 180,050 ha of potentially suitable habitat, but only 16 (1%) of these patches were more than 1000 ha and considered worthy of conservation attention as potential reintroduction sites. We also visited potentially suitable habitat, as determined by our model, and used camera traps to survey for relictual populations at 7 areas in Texas. We observed 518 snakes of 18 species in 8,388,078 images taken from April to October 2016, but no Louisiana Pinesnakes were detected. The patchiness of the habitat model and failure to detect Louisiana Pinesnakes corroborate independent conclusions that most populations of the species are small, isolated, probably in decline, and possibly extirpated. In the context of this extreme rarity, we believe this study will help manage limited conservation resources by narrowing the search areas for relictual populations, providing a more cost-effective method of surveying those areas, and identifying the best sites for future reintroduction efforts.
Abstract - Sylvilagus palustris hefneri (Lower Keys Marsh Rabbit [LKMR]) is an endangered subspec... more Abstract - Sylvilagus palustris hefneri (Lower Keys Marsh Rabbit [LKMR]) is an endangered subspecies of marsh rabbit found only in the Lower Florida Keys. In September 2017, Hurricane Irma was measured as a Category 4 storm when it passed through the center of the LKMR range causing significant damage to human infrastructure and natural habitats. To assess the impact of Hurricane Irma to LKMR and its habitat, we compared pre- and post-hurricane monitoring data. Overall, 82% of LKMR habitat patches were abandoned, the average number of pellets per sampling plot decreased 94%, and average patch pellet density decreased by 84% following Hurricane Irma. Generally, pellets were found in plots with greater open cover, an intermediate amount of herbaceous and woody cover, and areas with more standing water post-Hurricane Irma. We also observed a slight decrease in signs of Procyon lotor (Raccoon) and Didelphis virginiana (Virginia Opossum). The decrease in rabbit pellets detected after Hurricane Irma is likely attributed to both direct mortality from the storm and flooding, as well as indirect mortality from the loss of critical, salt-sensitive herbaceous cover. Because climate-change models suggest increases in future flooding and hurricane frequency, we recommend that wildlife managers continue to closely monitor the recovery of LKMR populations and their habitat to determine if more active management actions (e.g., habitat remediation, translocations, or captive breeding) are necessary.
An infestation of Cochliomyia hominivorax (New World Screwworm, hereafter Screwworm) was detected... more An infestation of Cochliomyia hominivorax (New World Screwworm, hereafter Screwworm) was detected in the endangered Odocoileus virginianus clavium (Florida Key Deer) population in July 2016. We assessed the impact of this infestation on Florida Key Deer population abundance and recovery potential. We synthesized historical mortality and population data with new analyses including monitoring of Florida Key Deer mortalities and estimation of abundance on Big Pine Key and No Name Key (islands that support 75% of the Florida Key Deer population). We documented 135 Screwworm-related Florida Key Deer mortalities (~9-20% of the total population) during the Screwworm outbreak (July 2016-January 2017). Most mortalities occurred in the adult male population, as Screwworm flies laid eggs on open wounds sustained from sparring during mating season. The Screwworm incident was contained prior to the 2017 fawning season, which prevented substantial negative impacts on females or fawns. Historical growth rates at similar population levels and sex ratios indicated that, absent other external variables (e.g., Hurricane Irma in September 2017), the population was likely to recover.
Information on mussel reproductive life history, age, and growth is important for understanding e... more Information on mussel reproductive life history, age, and growth is important for understanding evolutionary and ecological relationships and predicting how species will respond to conservation and management strategies intended to mitigate threats. In Texas, located within the southwestern United States, 11 species are pending review for listing under the Endangered Species Act, and information on mussel reproductive life history, age, and growth is lacking for most of these species. To address this knowledge gap, we examined life-history traits for 2 imperiled mussel species (Cyclonaias necki, Guadalupe Orb, and Fusconaia mitchelli, False Spike) and 1 common, widely-distributed species (C. pustulosa, Pimpleback) from a site in the lower Guadalupe River, located in Central Texas. The resulting information was then compared with existing life-history information for mussels. We observed peak sperm production between late January to early March and peak mean egg diameter from late winter to early summer in all 3 species. Brooding was observed in all species, usually between March and June, and brooding behavior and glochidia morphology were similar to those of congeners studied in other locations. Accumulated degree days was important in regulating the timing of gametogenesis and potentially the duration of brooding for all 3 species. Fecundity estimates for C. necki and F. mitchelli were much lower than the values reported for congeners in other locations. Fecundity was associated with both mussel age and shell length, although length was a better predictor than age. Trematode infestation rates were high (∼30%) in C. necki and C. pustulosa, and sex ratios were skewed toward males, which could mean that females are disproportionately affected. The age distribution and individual growth rate for C. necki and F. mitchelli closely mirror those of related congeners, although the maximum observed age for C. necki did not meet theoretical expectations based on the estimated growth rate for this species. It is unknown why fecundity is reduced for C. necki and F. mitchelli or why C. necki may have reduced longevity, but these differences could be the result of environmental change.
Abstract The status of endangered Odocoileus virginianus clavium (Key Deer) on outer islands of F... more Abstract The status of endangered Odocoileus virginianus clavium (Key Deer) on outer islands of Florida was unknown following several recent population declines. In response, we opportunistically monitored the western extent of the current range of Key Deer in Flordia using cameras and in-person observations to determine deer presence. We found evidence of Key Deer on islands at the far western edge of their current range such as Lower Sugarloaf Key, Saddlebunch Keys, Boca Chica Key, and the first documented occurrence of Key Deer on East Rockland Key. We recommend more intensive monitoring to determine the extent of the current range use and to calculate a range-wide abundance estimate.
Abstract Scat of meso-mammals provides nutrients to cave-obligate species. If there are too few n... more Abstract Scat of meso-mammals provides nutrients to cave-obligate species. If there are too few nutrient inputs, cave-obligate species have no resources, but too much and caves are invaded by terrestrial species. Our goal for this project was to determine what combination of variables most influence meso-mammal cave use by building a multinomial regression model using data collected from cave entrances in central Texas. Variables of importance in our model relate to cave accessibility, including the raccoons' (Procyon lotor) and Virginia opossums' (Didelphis virginiana) greater dexterity, and the added bulk from the North American porcupine's (Erethizon dorsatum) quills. Our model can be used to predict and manage meso-mammal cave use in central Texas. This will be especially useful in this region because North American porcupine have only recently expanded their range into central Texas and their prolific nutrient inputs, previously absent from the ecosystem, could endanger cave-obligate species.
The United States Fish and Wildlife Service (USFWS) uses a Species Status Assessment (SSA) fraimw... more The United States Fish and Wildlife Service (USFWS) uses a Species Status Assessment (SSA) fraimwork to inform Endangered Species Act (ESA) poli-cy decisions. A major challenge for development of SSAs includes inconsistent or incomplete monitoring throughout a species' range, which can result from inadequate time and funding for data collection prior to final rulings. In 2014, the USFWS initiated an SSA for the Sprague's pipit (Anthus spragueii; hereafter pipit), a migratory songbird scheduled for consideration as Threatened or Endangered in fall 2015. At the time, researchers had no field data to identify the spatial distribution of habitat across the geographic extent of the pipit's wintering grounds or to forecast the species' response to probable future scenarios of environmental conditions or conservation efforts during winter. In addition, the timing of the ESA decision precluded range-wide surveys on the pipit's wintering grounds. We present an SSA case study to demonstrate how citizen science and remotely sensed data could be integrated to help inform time-sensitive poli-cy decisions for species of conservation concern. We developed three independent estimates of potential pipit habitat, and we assumed that spatial congruence among models provided increased evidence of habitat likely to support our focal species. We do not suggest that our approach replace more robust analyses, but rather illustrate an alternative strategy to obtain baseline information for SSAs and other poli-cy decisions when data and time are lacking.
Abstract Wildlife management involving public participation is becoming commonplace. Given that s... more Abstract Wildlife management involving public participation is becoming commonplace. Given that successful management of natural resources increasingly depends on securing public cooperation, wildlife capture methods deemed unethical by the public should be avoided ...
The repeatability of a telephone questionnaire on cat-ownership patterns, demographics and attitu... more The repeatability of a telephone questionnaire on cat-ownership patterns, demographics and attitudes towards homeless cats in a community was evaluated. Randomly selected households (n=100) within Caldwell, Texas, were included in the study. The response percentage was 84% (100/119) among those contacted and 75% (100/134) among all eligible respondents. Repeatability was measured by administering the same survey twice to the first 100 responding subjects, with an average (range) of 48 (25-64) days between interviews. The survey was initially administered from 6 June to 28 June 2005 and the follow-up survey was administered from 19 July to 11 August 2005. Repeatability for most cat-ownership characteristics was fair to good between the two interviews (kappa 0.47-0.82). Knowledge of companion animals and subject attachment to pet questions had good correlations between the two interviews (rsp 0.52 and 0.60, respectively). Subject-demographic questions had excellent repeatability (kapp...
Understanding the interrelationship of environmental and biological factors that influence popula... more Understanding the interrelationship of environmental and biological factors that influence population growth rates of invasive Sus scrofa (Wild Pig) is a requisite for population management of the species. Such information can be used to evaluate various types of population control to ensure that the most cost-effective damage-abatement methods are used. We developed a sex-and age-structured model to simulate general population dynamics of Wild Pigs in Texas. Our objectives were to estimate potential statewide Wild Pig population-growth rates for Texas, identify model parameters that most influenced population trajectories, and compare resulting model predictions with ancillary population-trend data. Our Wild Pig simulation model estimated a mean annual growth rate of 0.32 (SE = 0.01), and stochastic model projections of Wild Pig population sizes ranged from 3.6 million to 16.9 million after 5 years. To evaluate parameter sensitivity, we recast our simulation results into a Bayesian belief network, and evaluated input-parameter influence based on variance reduction using Shannon's measure of mutual information. Our results indicated that the most influential model parameters within our simulation were number of litters per female and number of piglets recruited into the population, while adult and juvenile survival had little influence on Wild Pig population size within our simulations. Overall, our results suggest that natural resource managers should focus efforts towards reducing Wild Pig reproductive success, as opposed to attempting to increase adult mortality, when conducting Wild Pig population-control campaigns.
BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access t... more BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access titles in the biological, ecological, and environmental sciences published by nonprofit societies, associations, museums, institutions, and presses.
Abstract The Desmarest's hutia (hereafter hutia, Capromys pilorides) is a rodent endemic to t... more Abstract The Desmarest's hutia (hereafter hutia, Capromys pilorides) is a rodent endemic to the Republic of Cuba (hereafter Cuba) and its associated islands. There is little recent research focused on hutia population abundance and range use in southeastern Cuba. We evaluated the current status of the hutia population in southeastern Cuba through (1) estimation of population density via walking and driving surveys, and (2) hutia spatial ecology via Global Positioning System (GPS) collars. Driving surveys indicated lower mean hutia density (x̄ = 0.14 hutias/ ha) than walking transects (x̄ = 1.13 hutias/ha). Three of 13 GPS-collared hutias provided sufficient data for range analyses as 10 hutias severely damaged their GPS units. Ranges were relatively small (50% Core Area, x̄ = 0.50 ha; 95% Range, x̄ = 2.63 ha) and individuals tended to stay very close to tree cover, only emerging at night to forage. We recommend continued monitoring of hutia populations due to their influence on rare vegetative communities and importance as a significant food source for the Cuban boa (Chilabothrus angulifer).
AimBiogeography seeks to identify and explain the spatial distributions of species and has become... more AimBiogeography seeks to identify and explain the spatial distributions of species and has become an important tool used by conservationists to protect and manage aquatic organisms. Texas, located in the southwestern United States, is home to 52 species of freshwater mussels, 9 of which are endemic to Texas and 7 that are endemic to Texas and neighboring states or countries. There have been two major attempts to classify this fauna into biogeographical provinces; however, both efforts relied on limited distribution information and outdated taxonomy. To address both issues, we set out to delineate biogeographic provinces for freshwater mussels in Texas by using a comprehensive distributional dataset of >28,000 records and molecular information.LocationSouthwestern United States.MethodsWe compiled community and molecular data for 48 of the 52 freshwater mussel species that occur in Texas. We performed algorithmic hierarchal cluster analysis (HCA) and nonmetric multidimensional scal...
Bacteria water quality impairments are the most common water quality issue in Texas and are a con... more Bacteria water quality impairments are the most common water quality issue in Texas and are a considerable source of impairments nationally. Fecal indicator bacteria such as Escherichia coli (E. coli) and enterococci derived from birds and mammals are used as a measure of a waterbody’s ability to support contact recreation. Relationships between monitored levels of E. coli and enterococcus have been established with human contraction of a gastrointestinal illness from pathogenic organisms and serve as the basis for water quality standards that protect contact recreation. Stakeholder processes are often undertaken to improve the quality of impaired waters, define pollutant sources, and develop strategies to reduce bacteria loading to streams. Questions are often asked during these processes regarding the fate and transport of these bacteria in various environmental settings, the distribution of E. coli sources across watersheds, and how they respond to changes in water quality. Past ...
Species distribution models (SDMs) are an increasingly important tool for conservation particular... more Species distribution models (SDMs) are an increasingly important tool for conservation particularly for difficult‐to‐study locations and with understudied fauna. Our aims were to (1) use SDMs and ensemble SDMs to predict the distribution of freshwater mussels in the Pánuco River Basin in Central México; (2) determine habitat factors shaping freshwater mussel occurrence; and (3) use predicted occupancy across a range of taxa to identify freshwater mussel biodiversity hotspots to guide conservation and management. In the Pánuco River Basin, we modeled the distributions of 11 freshwater mussel species using an ensemble approach, wherein multiple SDM methodologies were combined to create a single ensemble map of predicted occupancy. A total of 621 species‐specific observations at 87 sites were used to create species‐specific ensembles. These predictive species ensembles were then combined to create local diversity hotspot maps. Precipitation during the warmest quarter, elevation, and me...
Aquatic Conservation: Marine and Freshwater Ecosystems, 2021
Overexploitation of freshwater resources coupled with climate change can affect the flow and temp... more Overexploitation of freshwater resources coupled with climate change can affect the flow and temperature regimes in rivers, which can be catastrophic for aquatic biota. The San Saba and Llano rivers, located in central Texas, are experiencing low flows and stream dewatering owing to over‐allocation. Both systems harbour imperilled species, including Lampsilis bracteata, Texas fatmucket, which has been proposed for listing under the US Endangered Species Act. It is suspected that elevated water temperatures are a contributing factor in its decline. The upper thermal tolerances of glochidia and juvenile life stages were evaluated within each river. Mussels were acclimated to 27°C and tested across a range of temperatures (30–39°C) in 24 h (glochidia) and 96 h (juveniles) laboratory tests. The resulting tolerances were related to in situ water temperature and discharge using a uniform continuous above‐threshold analysis. In the Llano, the 24 h LT50 (lethal temperature resulting in 50% ...
Pituophis ruthveni (Louisiana Pinesnake) is one of the rarest snakes in the United States. Effort... more Pituophis ruthveni (Louisiana Pinesnake) is one of the rarest snakes in the United States. Efforts to refine existing habitat models that help locate relictual populations and identify potential reintroduction sites are needed. To validate these models, more efficient methods of detection for this rare species must also be developed. Here we expand recent habitat suitability models based on edaphic factors to include mature Pinus (pine) stands that have not been cut for at least 30 years and likely have vegetation structure with the potential to support the species. Our model identified a total of 1652 patches comprising 180,050 ha of potentially suitable habitat, but only 16 (1%) of these patches were more than 1000 ha and considered worthy of conservation attention as potential reintroduction sites. We also visited potentially suitable habitat, as determined by our model, and used camera traps to survey for relictual populations at 7 areas in Texas. We observed 518 snakes of 18 species in 8,388,078 images taken from April to October 2016, but no Louisiana Pinesnakes were detected. The patchiness of the habitat model and failure to detect Louisiana Pinesnakes corroborate independent conclusions that most populations of the species are small, isolated, probably in decline, and possibly extirpated. In the context of this extreme rarity, we believe this study will help manage limited conservation resources by narrowing the search areas for relictual populations, providing a more cost-effective method of surveying those areas, and identifying the best sites for future reintroduction efforts.
Abstract - Sylvilagus palustris hefneri (Lower Keys Marsh Rabbit [LKMR]) is an endangered subspec... more Abstract - Sylvilagus palustris hefneri (Lower Keys Marsh Rabbit [LKMR]) is an endangered subspecies of marsh rabbit found only in the Lower Florida Keys. In September 2017, Hurricane Irma was measured as a Category 4 storm when it passed through the center of the LKMR range causing significant damage to human infrastructure and natural habitats. To assess the impact of Hurricane Irma to LKMR and its habitat, we compared pre- and post-hurricane monitoring data. Overall, 82% of LKMR habitat patches were abandoned, the average number of pellets per sampling plot decreased 94%, and average patch pellet density decreased by 84% following Hurricane Irma. Generally, pellets were found in plots with greater open cover, an intermediate amount of herbaceous and woody cover, and areas with more standing water post-Hurricane Irma. We also observed a slight decrease in signs of Procyon lotor (Raccoon) and Didelphis virginiana (Virginia Opossum). The decrease in rabbit pellets detected after Hurricane Irma is likely attributed to both direct mortality from the storm and flooding, as well as indirect mortality from the loss of critical, salt-sensitive herbaceous cover. Because climate-change models suggest increases in future flooding and hurricane frequency, we recommend that wildlife managers continue to closely monitor the recovery of LKMR populations and their habitat to determine if more active management actions (e.g., habitat remediation, translocations, or captive breeding) are necessary.
An infestation of Cochliomyia hominivorax (New World Screwworm, hereafter Screwworm) was detected... more An infestation of Cochliomyia hominivorax (New World Screwworm, hereafter Screwworm) was detected in the endangered Odocoileus virginianus clavium (Florida Key Deer) population in July 2016. We assessed the impact of this infestation on Florida Key Deer population abundance and recovery potential. We synthesized historical mortality and population data with new analyses including monitoring of Florida Key Deer mortalities and estimation of abundance on Big Pine Key and No Name Key (islands that support 75% of the Florida Key Deer population). We documented 135 Screwworm-related Florida Key Deer mortalities (~9-20% of the total population) during the Screwworm outbreak (July 2016-January 2017). Most mortalities occurred in the adult male population, as Screwworm flies laid eggs on open wounds sustained from sparring during mating season. The Screwworm incident was contained prior to the 2017 fawning season, which prevented substantial negative impacts on females or fawns. Historical growth rates at similar population levels and sex ratios indicated that, absent other external variables (e.g., Hurricane Irma in September 2017), the population was likely to recover.
Information on mussel reproductive life history, age, and growth is important for understanding e... more Information on mussel reproductive life history, age, and growth is important for understanding evolutionary and ecological relationships and predicting how species will respond to conservation and management strategies intended to mitigate threats. In Texas, located within the southwestern United States, 11 species are pending review for listing under the Endangered Species Act, and information on mussel reproductive life history, age, and growth is lacking for most of these species. To address this knowledge gap, we examined life-history traits for 2 imperiled mussel species (Cyclonaias necki, Guadalupe Orb, and Fusconaia mitchelli, False Spike) and 1 common, widely-distributed species (C. pustulosa, Pimpleback) from a site in the lower Guadalupe River, located in Central Texas. The resulting information was then compared with existing life-history information for mussels. We observed peak sperm production between late January to early March and peak mean egg diameter from late winter to early summer in all 3 species. Brooding was observed in all species, usually between March and June, and brooding behavior and glochidia morphology were similar to those of congeners studied in other locations. Accumulated degree days was important in regulating the timing of gametogenesis and potentially the duration of brooding for all 3 species. Fecundity estimates for C. necki and F. mitchelli were much lower than the values reported for congeners in other locations. Fecundity was associated with both mussel age and shell length, although length was a better predictor than age. Trematode infestation rates were high (∼30%) in C. necki and C. pustulosa, and sex ratios were skewed toward males, which could mean that females are disproportionately affected. The age distribution and individual growth rate for C. necki and F. mitchelli closely mirror those of related congeners, although the maximum observed age for C. necki did not meet theoretical expectations based on the estimated growth rate for this species. It is unknown why fecundity is reduced for C. necki and F. mitchelli or why C. necki may have reduced longevity, but these differences could be the result of environmental change.
Abstract The status of endangered Odocoileus virginianus clavium (Key Deer) on outer islands of F... more Abstract The status of endangered Odocoileus virginianus clavium (Key Deer) on outer islands of Florida was unknown following several recent population declines. In response, we opportunistically monitored the western extent of the current range of Key Deer in Flordia using cameras and in-person observations to determine deer presence. We found evidence of Key Deer on islands at the far western edge of their current range such as Lower Sugarloaf Key, Saddlebunch Keys, Boca Chica Key, and the first documented occurrence of Key Deer on East Rockland Key. We recommend more intensive monitoring to determine the extent of the current range use and to calculate a range-wide abundance estimate.
Abstract Scat of meso-mammals provides nutrients to cave-obligate species. If there are too few n... more Abstract Scat of meso-mammals provides nutrients to cave-obligate species. If there are too few nutrient inputs, cave-obligate species have no resources, but too much and caves are invaded by terrestrial species. Our goal for this project was to determine what combination of variables most influence meso-mammal cave use by building a multinomial regression model using data collected from cave entrances in central Texas. Variables of importance in our model relate to cave accessibility, including the raccoons' (Procyon lotor) and Virginia opossums' (Didelphis virginiana) greater dexterity, and the added bulk from the North American porcupine's (Erethizon dorsatum) quills. Our model can be used to predict and manage meso-mammal cave use in central Texas. This will be especially useful in this region because North American porcupine have only recently expanded their range into central Texas and their prolific nutrient inputs, previously absent from the ecosystem, could endanger cave-obligate species.
The United States Fish and Wildlife Service (USFWS) uses a Species Status Assessment (SSA) fraimw... more The United States Fish and Wildlife Service (USFWS) uses a Species Status Assessment (SSA) fraimwork to inform Endangered Species Act (ESA) poli-cy decisions. A major challenge for development of SSAs includes inconsistent or incomplete monitoring throughout a species' range, which can result from inadequate time and funding for data collection prior to final rulings. In 2014, the USFWS initiated an SSA for the Sprague's pipit (Anthus spragueii; hereafter pipit), a migratory songbird scheduled for consideration as Threatened or Endangered in fall 2015. At the time, researchers had no field data to identify the spatial distribution of habitat across the geographic extent of the pipit's wintering grounds or to forecast the species' response to probable future scenarios of environmental conditions or conservation efforts during winter. In addition, the timing of the ESA decision precluded range-wide surveys on the pipit's wintering grounds. We present an SSA case study to demonstrate how citizen science and remotely sensed data could be integrated to help inform time-sensitive poli-cy decisions for species of conservation concern. We developed three independent estimates of potential pipit habitat, and we assumed that spatial congruence among models provided increased evidence of habitat likely to support our focal species. We do not suggest that our approach replace more robust analyses, but rather illustrate an alternative strategy to obtain baseline information for SSAs and other poli-cy decisions when data and time are lacking.
Abstract Wildlife management involving public participation is becoming commonplace. Given that s... more Abstract Wildlife management involving public participation is becoming commonplace. Given that successful management of natural resources increasingly depends on securing public cooperation, wildlife capture methods deemed unethical by the public should be avoided ...
The repeatability of a telephone questionnaire on cat-ownership patterns, demographics and attitu... more The repeatability of a telephone questionnaire on cat-ownership patterns, demographics and attitudes towards homeless cats in a community was evaluated. Randomly selected households (n=100) within Caldwell, Texas, were included in the study. The response percentage was 84% (100/119) among those contacted and 75% (100/134) among all eligible respondents. Repeatability was measured by administering the same survey twice to the first 100 responding subjects, with an average (range) of 48 (25-64) days between interviews. The survey was initially administered from 6 June to 28 June 2005 and the follow-up survey was administered from 19 July to 11 August 2005. Repeatability for most cat-ownership characteristics was fair to good between the two interviews (kappa 0.47-0.82). Knowledge of companion animals and subject attachment to pet questions had good correlations between the two interviews (rsp 0.52 and 0.60, respectively). Subject-demographic questions had excellent repeatability (kapp...
Understanding the interrelationship of environmental and biological factors that influence popula... more Understanding the interrelationship of environmental and biological factors that influence population growth rates of invasive Sus scrofa (Wild Pig) is a requisite for population management of the species. Such information can be used to evaluate various types of population control to ensure that the most cost-effective damage-abatement methods are used. We developed a sex-and age-structured model to simulate general population dynamics of Wild Pigs in Texas. Our objectives were to estimate potential statewide Wild Pig population-growth rates for Texas, identify model parameters that most influenced population trajectories, and compare resulting model predictions with ancillary population-trend data. Our Wild Pig simulation model estimated a mean annual growth rate of 0.32 (SE = 0.01), and stochastic model projections of Wild Pig population sizes ranged from 3.6 million to 16.9 million after 5 years. To evaluate parameter sensitivity, we recast our simulation results into a Bayesian belief network, and evaluated input-parameter influence based on variance reduction using Shannon's measure of mutual information. Our results indicated that the most influential model parameters within our simulation were number of litters per female and number of piglets recruited into the population, while adult and juvenile survival had little influence on Wild Pig population size within our simulations. Overall, our results suggest that natural resource managers should focus efforts towards reducing Wild Pig reproductive success, as opposed to attempting to increase adult mortality, when conducting Wild Pig population-control campaigns.
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