Florida scrub habitat is a naturally fire maintained habitat that is highly endangered because of... more Florida scrub habitat is a naturally fire maintained habitat that is highly endangered because of great demand for land for agriculture and real estate. Maintenance of remaining patches ofFlorida scrub habitat requires active management. We experimentally investigated the effects of clearcutting and burning on sand skink populations in three patches of sand pine scrub. Each patch included a clearcut plot, a burned plot, and an undisturbed plot. Treatment plot boundaries were drawn in 1995 such that each plot was no different from any other plot in sand skink densities. The responses of sand skink and other herpetofauna populations were monitored over the following five-year period (1996-2000) immediately following clearcutting and burning. Initially, sand skink captures in the burned and clearcut plots were lower than in the undisturbed plots. Over the five-year period, sand skink captures significantly increased in the clearcut plots. No clear trend occurred in the burned plots, although fluctuations from year to year were significant. After treatment, number of sand skink captures differed among treatment plots within each site. The treatments also did not affect sand skink distributions within the sites in the same way among the sites. The distribution of sand skinks within the three sites appeared to be influenced by an interaction between treatment plot and microhabitat characteristics. Sand skink presence has been related previously to low soil compaction, large soil particle size, low soil moisture, low soil temperature, large amounts of loose sand and bare ground, and low average understory vegetation. The treatment plot in which the sand skinks were found in the greatest numbers may have been more a function of the microhabitat characteristics rather than the treatment. Analysis o f the distribution of individuals also indicated that sand skink distribution was clumped, especially near the centers of the three sites. Analysis of herpetofaunal data from the experimental sites indicated that toward the end of the study, the number of species captured appeared to be converging among the undisturbed, clearcut, and burned plots. Diversity estimates, however, which incorporate number of individuals as well as number of species, indicated that the burned and undisturbed plots had greater herpetofaunal diversity than the clearcut plots. Comparisons were made with other studies performed in north central Florida (Ocala National Forest) and southern Florida
Numerous biotic and abiotic agents of disturbance operating at different scales influence the div... more Numerous biotic and abiotic agents of disturbance operating at different scales influence the diversity, composition, architecture, spatial patterning, and productivity of a variety of community types (e.g., Loucks, 1970; Dayton, 1971; Grubb, 1977; Connell, 1978; Greig-Smith, 1979; White, 1979; Pickett, 1980; Paine and Levin, 1981; Runkle, 1981; Bazzaz, 1984). Disturbance can play a significant role as an agent of selection (Pickett, 1976). Specific characteristics of disturbance which influence community ecology include frequency, time, intensity, and spatial context of disturbance agents (e.g., Sousa, 1979; Abugov, 1982; Miller, 1982; Bazzaz, 1984). Fire is a significant abiotic agent of disturbance that influences the structure of many communities around the world and the evolution of species’ strategies.
Conservation translocations are occurring at ever-increasing rates (Seddon, Armstrong & Malon... more Conservation translocations are occurring at ever-increasing rates (Seddon, Armstrong & Maloney, 2007). These include reintroduction, reinforcement and more recently, ecological replacement and assisted colonization (Seddon et al., 2014). Additionally, over the past two decades, there has also been an increase in the movements of animals as minimization or mitigation for human development (Miller, Bell & Germano, 2014; Germano et al., 2014; Sullivan, Nowak & Kwiatkowski, 2014). Alongside the overall increase in the number of conservation translocations occurring worldwide, there has also been a shift in how these releases are carried out. While many early translocations occurred as isolated management projects, there has been a move to better monitoring and research that tests a priori questions and theories. This helps add to our knowledge base and ability to carry out more effective releases (Ewen et al., 2012). It is critical that the literature reflects advances made in conservation translocations so that solutions are shared across the growing application of this conservation management tool and its use as a valid technique for mitigation or minimization during development. Despite the need by conservation practitioners for knowledge that can be applied to a broad range of circumstances, past studies have shown a marked taxonomic bias both within conservation translocation projects being carried out (Seddon, Soorae & Launay, 2005) and within those translocations that make it to the published literature (Bajomi et al., 2010). In both of these cases, the bias has been towards vertebrates with a further overrepresentation of mammals and birds within the vertebrate groups (Seddon et al., 2005; Bajomi et al., 2010). This special issue has two aims: first, to present a collection of articles covering recent advances in conservation translocation, and, second, to do so by highlighting translocations from one under-represented taxonomic group, herpetofauna. We hope that this will provide a valuable resource to the translocation community and help guide amphibian and reptile translocations in the future. One of the common concerns discussed in this collection of papers and in the literature is the need for well defined criteria for success as part of any translocation initiative (Seddon, 1999; Miller et al., 2014). Ideally, these criteria should be compatible with the biology of the target species and the socio-economic context in which the translocation is developed. Ewen et al. (2014) present an analysis of the range of both biological and non-biological objectives set by translocation practitioners to assess the success of herpetofauna translocations and what aspects are being judged as affecting the outcomes of these translocations. Their study calls for a more rigorous development of translocation objectives and a clearer distinction between required technical improvements as means of moving towards more fundamental project goals such as population establishment. Once criteria for success are clearly stated, the next important step is to find ways to improve the chances of success by careful planning. Much of this planning depends upon knowledge of the biological, ecological and behavioural needs of the target species. McCoy et al. (2014) experimentally explore the complex interactions of environmental conditions and their relationship to translocation success of the threatened Florida sand skink (Plestiodon reynoldsi). Their study highlights the importance of habitat heterogeneity, available micro-habitats at recipient sites and the behavioural choices of the species for initial survival and reproduction. Aiello et al.’s (2014) study reinforces the need to consider behaviour more prominently in translocation efforts with a particular focus on the interactions of behaviour and disease risks. They offer a caution about use of translocations to either top-up remnant populations, follow-up on previous translocations or otherwise release animals at sites where there are conspecifics. Their study presents a model of disease dynamics with altered transmission rates through changes in contact networks following translocation of host animals. Preliminary modelling of a case study, the Mojave desert tortoise (Gopherus agassizii) bs_bs_banner
The striped mud turtle, Kinosternon baurii, is a common small aquatic turtle easily recognized by... more The striped mud turtle, Kinosternon baurii, is a common small aquatic turtle easily recognized by three light longitudinal stripes on a darker shell. It ranges from the lower Florida Keys to southern Virginia. Although this species is known to occupy a wide range of aquatic habitats, few data exist on its precise habitat requirements in Florida. Both males and females tend to spend a considerable amount of time on land and these movements are positively correlated with precipitation. Adult females nest in the spring and fall months with the majority of nesting events recorded in September through November. This species is known to have a remarkable developmental pattern that in some cases includes two separate periods of diapause (when development temporarily shuts down). Because eggs are deposited in a relatively shallow nest, vegetative cover around the nest has been shown to be important to protect developing offspring from thermal extremes. Much of the basic population biology of this species remains poorly known. No single population has been followed for a period long enough to monitor patterns of survivorship, fecundity, or growth rates. In addition, most research on this species has focused on adult females with a paucity of data on males or juveniles. Although striped mud turtles appear relatively abundant north of the Florida Keys, populations in the lower Keys are listed as endangered by the Florida Fish and Wildlife Conservation Commission. The main threat in the lower Florida Keys appears to be intensive development of their habitat, most of which is privately owned
Numbers of gopher tortoises are declining throughout the southeastern United States, largely beca... more Numbers of gopher tortoises are declining throughout the southeastern United States, largely because of loss of habitat. Widespread monitoring of population sizes for gopher tortoises usually is done indirectly, by examining the burrows that tortoises construct. Indirect monitoring requires use of a correction factor, to relate numbers of burrows to numbers of tortoises. We demonstrate that the standard correction factor overestimates the number of tortoises in 22 of the 26 cases in our sample and that the relationship between numbers of burrows and numbers of tortoises differs among types of habitats. Using both published data and data from our own studies, we suggest that an accurate assessment of active burrows is a reliable way to relate numbers of burrows to numbers of tortoises.
The southeastern five-lined skink, Eumeces inexpectatus, occurs in a wide range of habitats throu... more The southeastern five-lined skink, Eumeces inexpectatus, occurs in a wide range of habitats throughout Florida, but it is most abundant in scrub and sandhill (high pine) habitats. Both the scrub and sandhill habitats are fire maintained, and resident animals respond to the frequency of burning. During 7 yr of study, adult males were trapped most often in March and April and adult females most often after nesting and hatching of young, from late June to mid- July. As judged by the number of individuals captured, I determined that plots of sandhill protected from fire for about two decades or burned on 5 or 7 yr cycles support more individuals than plots burned on either 1 or 2 yr cycles. Differences in the number of skinks found in plots subjected to the three burn frequencies likely reflect the structure of the habitat. Frequent burning reduces the amount of litter and tree canopy, produces patches of open ground, and promotes the growth of herbaceous plants. Plots protected from fire have thick layers of litter which provide shelter and foraging habitat for southeastern five-lined skinks. Plots burned on 5 or 7 yr cycles have sufficient time to accumulate litter between fires to provide good quality habitat for this species.
... and Christman (1982) stated that amphibian and reptile faunas of Florida sandhills were not d... more ... and Christman (1982) stated that amphibian and reptile faunas of Florida sandhills were not determined by a particular plant association, but rather by the physical characteristics of the habitat. They found higher species diversity and greater abun-dance of individuals in young ...
A recent study showed that populations of the threatened Florida Sand Skink had limited loss of g... more A recent study showed that populations of the threatened Florida Sand Skink had limited loss of genetic diversity over the past 60 yr as a consequence of anthropogenic fragmentation. This study assumed that 60 yr represents 3037 generations for the Florida Sand Skink, but a ...
Abstract The threatened Bluetail Mole Skink (Plestiodon egregius lividus) is limited to the xeric... more Abstract The threatened Bluetail Mole Skink (Plestiodon egregius lividus) is limited to the xeric habitats of the southern Lake Wales Ridge in central Florida. To generate important data for conserving this species, we characterized genetic variation at the mitochondrial cytochrome-b gene and seven microsatellite loci among multiple populations. We compared the Bluetail Mole Skink's pattern of genetic diversity and differentiation to those of two other lizards with similar geographic and habitat distributions—the Florida Sand Skink (Plestiodon reynoldsi) and the Florida Scrub Lizard (Sceloporus woodi). The Bluetail Mole Skink was highly variable at the genetic markers, and significant genetic differentiation occurred among scrub patches. Patches can be divided into central and southern Lake Wales Ridge groups. Our results also suggest that each sampled habitat patch should be treated as a population and reintroductions should minimize the distance between recipient and source locations to limit altering the potential long-term pattern of genetic differentiation among Bluetail Mole Skinks on the Lake Wales Ridge. The Bluetail Mole Skink and the Florida Sand Skink had similar genetic diversity, and all three lizards had comparable patterns of genetic differentiation. The concordance of genetic differentiation among these species is further evidence suggesting that similar conservation issues face the three species, namely, preserving the remaining xeric habitat. It is likely, therefore, that conservation efforts directed at the more common Florida Sand Skink and Florida Scrub Lizard would benefit the Bluetail Mole Skink.
Florida scrub habitat is a naturally fire maintained habitat that is highly endangered because of... more Florida scrub habitat is a naturally fire maintained habitat that is highly endangered because of great demand for land for agriculture and real estate. Maintenance of remaining patches ofFlorida scrub habitat requires active management. We experimentally investigated the effects of clearcutting and burning on sand skink populations in three patches of sand pine scrub. Each patch included a clearcut plot, a burned plot, and an undisturbed plot. Treatment plot boundaries were drawn in 1995 such that each plot was no different from any other plot in sand skink densities. The responses of sand skink and other herpetofauna populations were monitored over the following five-year period (1996-2000) immediately following clearcutting and burning. Initially, sand skink captures in the burned and clearcut plots were lower than in the undisturbed plots. Over the five-year period, sand skink captures significantly increased in the clearcut plots. No clear trend occurred in the burned plots, although fluctuations from year to year were significant. After treatment, number of sand skink captures differed among treatment plots within each site. The treatments also did not affect sand skink distributions within the sites in the same way among the sites. The distribution of sand skinks within the three sites appeared to be influenced by an interaction between treatment plot and microhabitat characteristics. Sand skink presence has been related previously to low soil compaction, large soil particle size, low soil moisture, low soil temperature, large amounts of loose sand and bare ground, and low average understory vegetation. The treatment plot in which the sand skinks were found in the greatest numbers may have been more a function of the microhabitat characteristics rather than the treatment. Analysis o f the distribution of individuals also indicated that sand skink distribution was clumped, especially near the centers of the three sites. Analysis of herpetofaunal data from the experimental sites indicated that toward the end of the study, the number of species captured appeared to be converging among the undisturbed, clearcut, and burned plots. Diversity estimates, however, which incorporate number of individuals as well as number of species, indicated that the burned and undisturbed plots had greater herpetofaunal diversity than the clearcut plots. Comparisons were made with other studies performed in north central Florida (Ocala National Forest) and southern Florida
Numerous biotic and abiotic agents of disturbance operating at different scales influence the div... more Numerous biotic and abiotic agents of disturbance operating at different scales influence the diversity, composition, architecture, spatial patterning, and productivity of a variety of community types (e.g., Loucks, 1970; Dayton, 1971; Grubb, 1977; Connell, 1978; Greig-Smith, 1979; White, 1979; Pickett, 1980; Paine and Levin, 1981; Runkle, 1981; Bazzaz, 1984). Disturbance can play a significant role as an agent of selection (Pickett, 1976). Specific characteristics of disturbance which influence community ecology include frequency, time, intensity, and spatial context of disturbance agents (e.g., Sousa, 1979; Abugov, 1982; Miller, 1982; Bazzaz, 1984). Fire is a significant abiotic agent of disturbance that influences the structure of many communities around the world and the evolution of species’ strategies.
Conservation translocations are occurring at ever-increasing rates (Seddon, Armstrong & Malon... more Conservation translocations are occurring at ever-increasing rates (Seddon, Armstrong & Maloney, 2007). These include reintroduction, reinforcement and more recently, ecological replacement and assisted colonization (Seddon et al., 2014). Additionally, over the past two decades, there has also been an increase in the movements of animals as minimization or mitigation for human development (Miller, Bell & Germano, 2014; Germano et al., 2014; Sullivan, Nowak & Kwiatkowski, 2014). Alongside the overall increase in the number of conservation translocations occurring worldwide, there has also been a shift in how these releases are carried out. While many early translocations occurred as isolated management projects, there has been a move to better monitoring and research that tests a priori questions and theories. This helps add to our knowledge base and ability to carry out more effective releases (Ewen et al., 2012). It is critical that the literature reflects advances made in conservation translocations so that solutions are shared across the growing application of this conservation management tool and its use as a valid technique for mitigation or minimization during development. Despite the need by conservation practitioners for knowledge that can be applied to a broad range of circumstances, past studies have shown a marked taxonomic bias both within conservation translocation projects being carried out (Seddon, Soorae & Launay, 2005) and within those translocations that make it to the published literature (Bajomi et al., 2010). In both of these cases, the bias has been towards vertebrates with a further overrepresentation of mammals and birds within the vertebrate groups (Seddon et al., 2005; Bajomi et al., 2010). This special issue has two aims: first, to present a collection of articles covering recent advances in conservation translocation, and, second, to do so by highlighting translocations from one under-represented taxonomic group, herpetofauna. We hope that this will provide a valuable resource to the translocation community and help guide amphibian and reptile translocations in the future. One of the common concerns discussed in this collection of papers and in the literature is the need for well defined criteria for success as part of any translocation initiative (Seddon, 1999; Miller et al., 2014). Ideally, these criteria should be compatible with the biology of the target species and the socio-economic context in which the translocation is developed. Ewen et al. (2014) present an analysis of the range of both biological and non-biological objectives set by translocation practitioners to assess the success of herpetofauna translocations and what aspects are being judged as affecting the outcomes of these translocations. Their study calls for a more rigorous development of translocation objectives and a clearer distinction between required technical improvements as means of moving towards more fundamental project goals such as population establishment. Once criteria for success are clearly stated, the next important step is to find ways to improve the chances of success by careful planning. Much of this planning depends upon knowledge of the biological, ecological and behavioural needs of the target species. McCoy et al. (2014) experimentally explore the complex interactions of environmental conditions and their relationship to translocation success of the threatened Florida sand skink (Plestiodon reynoldsi). Their study highlights the importance of habitat heterogeneity, available micro-habitats at recipient sites and the behavioural choices of the species for initial survival and reproduction. Aiello et al.’s (2014) study reinforces the need to consider behaviour more prominently in translocation efforts with a particular focus on the interactions of behaviour and disease risks. They offer a caution about use of translocations to either top-up remnant populations, follow-up on previous translocations or otherwise release animals at sites where there are conspecifics. Their study presents a model of disease dynamics with altered transmission rates through changes in contact networks following translocation of host animals. Preliminary modelling of a case study, the Mojave desert tortoise (Gopherus agassizii) bs_bs_banner
The striped mud turtle, Kinosternon baurii, is a common small aquatic turtle easily recognized by... more The striped mud turtle, Kinosternon baurii, is a common small aquatic turtle easily recognized by three light longitudinal stripes on a darker shell. It ranges from the lower Florida Keys to southern Virginia. Although this species is known to occupy a wide range of aquatic habitats, few data exist on its precise habitat requirements in Florida. Both males and females tend to spend a considerable amount of time on land and these movements are positively correlated with precipitation. Adult females nest in the spring and fall months with the majority of nesting events recorded in September through November. This species is known to have a remarkable developmental pattern that in some cases includes two separate periods of diapause (when development temporarily shuts down). Because eggs are deposited in a relatively shallow nest, vegetative cover around the nest has been shown to be important to protect developing offspring from thermal extremes. Much of the basic population biology of this species remains poorly known. No single population has been followed for a period long enough to monitor patterns of survivorship, fecundity, or growth rates. In addition, most research on this species has focused on adult females with a paucity of data on males or juveniles. Although striped mud turtles appear relatively abundant north of the Florida Keys, populations in the lower Keys are listed as endangered by the Florida Fish and Wildlife Conservation Commission. The main threat in the lower Florida Keys appears to be intensive development of their habitat, most of which is privately owned
Numbers of gopher tortoises are declining throughout the southeastern United States, largely beca... more Numbers of gopher tortoises are declining throughout the southeastern United States, largely because of loss of habitat. Widespread monitoring of population sizes for gopher tortoises usually is done indirectly, by examining the burrows that tortoises construct. Indirect monitoring requires use of a correction factor, to relate numbers of burrows to numbers of tortoises. We demonstrate that the standard correction factor overestimates the number of tortoises in 22 of the 26 cases in our sample and that the relationship between numbers of burrows and numbers of tortoises differs among types of habitats. Using both published data and data from our own studies, we suggest that an accurate assessment of active burrows is a reliable way to relate numbers of burrows to numbers of tortoises.
The southeastern five-lined skink, Eumeces inexpectatus, occurs in a wide range of habitats throu... more The southeastern five-lined skink, Eumeces inexpectatus, occurs in a wide range of habitats throughout Florida, but it is most abundant in scrub and sandhill (high pine) habitats. Both the scrub and sandhill habitats are fire maintained, and resident animals respond to the frequency of burning. During 7 yr of study, adult males were trapped most often in March and April and adult females most often after nesting and hatching of young, from late June to mid- July. As judged by the number of individuals captured, I determined that plots of sandhill protected from fire for about two decades or burned on 5 or 7 yr cycles support more individuals than plots burned on either 1 or 2 yr cycles. Differences in the number of skinks found in plots subjected to the three burn frequencies likely reflect the structure of the habitat. Frequent burning reduces the amount of litter and tree canopy, produces patches of open ground, and promotes the growth of herbaceous plants. Plots protected from fire have thick layers of litter which provide shelter and foraging habitat for southeastern five-lined skinks. Plots burned on 5 or 7 yr cycles have sufficient time to accumulate litter between fires to provide good quality habitat for this species.
... and Christman (1982) stated that amphibian and reptile faunas of Florida sandhills were not d... more ... and Christman (1982) stated that amphibian and reptile faunas of Florida sandhills were not determined by a particular plant association, but rather by the physical characteristics of the habitat. They found higher species diversity and greater abun-dance of individuals in young ...
A recent study showed that populations of the threatened Florida Sand Skink had limited loss of g... more A recent study showed that populations of the threatened Florida Sand Skink had limited loss of genetic diversity over the past 60 yr as a consequence of anthropogenic fragmentation. This study assumed that 60 yr represents 3037 generations for the Florida Sand Skink, but a ...
Abstract The threatened Bluetail Mole Skink (Plestiodon egregius lividus) is limited to the xeric... more Abstract The threatened Bluetail Mole Skink (Plestiodon egregius lividus) is limited to the xeric habitats of the southern Lake Wales Ridge in central Florida. To generate important data for conserving this species, we characterized genetic variation at the mitochondrial cytochrome-b gene and seven microsatellite loci among multiple populations. We compared the Bluetail Mole Skink's pattern of genetic diversity and differentiation to those of two other lizards with similar geographic and habitat distributions—the Florida Sand Skink (Plestiodon reynoldsi) and the Florida Scrub Lizard (Sceloporus woodi). The Bluetail Mole Skink was highly variable at the genetic markers, and significant genetic differentiation occurred among scrub patches. Patches can be divided into central and southern Lake Wales Ridge groups. Our results also suggest that each sampled habitat patch should be treated as a population and reintroductions should minimize the distance between recipient and source locations to limit altering the potential long-term pattern of genetic differentiation among Bluetail Mole Skinks on the Lake Wales Ridge. The Bluetail Mole Skink and the Florida Sand Skink had similar genetic diversity, and all three lizards had comparable patterns of genetic differentiation. The concordance of genetic differentiation among these species is further evidence suggesting that similar conservation issues face the three species, namely, preserving the remaining xeric habitat. It is likely, therefore, that conservation efforts directed at the more common Florida Sand Skink and Florida Scrub Lizard would benefit the Bluetail Mole Skink.
Uploads