Species Of Special Concern Research Articles

Genetic Characterization of the Savannah and Pee Dee River Populations of Robust Redhorse (Moxostoma robustum) with Conservation Implications

Robust Redhorse (Moxostoma robustum) is a deep-dwelling catostomid that lives in southeastern rivers of the United States. After being lost to science for about 100 years, M. robustum was rediscovered in the 1980s by the Georgia DNR and is a federal species of special concern. Our goal was to genetically characterize populations of M. robustum in the Savannah and Pee Dee rivers based on genetic diversity and population structure using a suite of ten microsatellites. Substantial levels of population structure were detected between rivers (RST = 0.308), with high genetic diversity (0.81–0.87) and low inbreeding in both systems. Long-term estimates of effective population sizes were very high for both systems, but contemporary estimates were substantially lower, with the Pee Dee River estimate being of concern from a conservation standpoint. Their long life span and overlapping generations result in a high potential for across-year-class spawning and are likely contributing to the maintenance of high genet...

Nocturnal field use by fall migrating American woodcock in the Delta of Arkansas

ABSTRACTThe American woodcock (Scolopax minor) population has declined since the late 1960s across its range and is now considered a species of special concern. Research on woodcock habitat use during migration and migratory routes through the Central Flyway has been limited. We assessed woodcock phenology, estimated density, and nocturnal habitat use in fields on public lands in the lower Mississippi Alluvial Valley portion of Arkansas during November and December of 2010 and 2011. We used all‐terrain vehicles to survey woodcock along transects in 67 fields of 8 field types. We analyzed data using hierarchical distance sampling. We detected woodcock from the first week in November through the third week in December but in low numbers. We did not detect woodcock in millet or rice fields, whereas woodcock had the highest estimated densities in unharvested soybeans. All other crop type–post‐harvest management combinations had low woodcock densities. We did not detect woodcock in fields <8 ha or >40 ha. Woodcock in the lower Mississippi Alluvial Valley may benefit from management for unharvested soybean fields of moderate size (approx. 8–40 ha). © 2014 The Wildlife Society.

A protected area influences genotype‐specific survival and the structure of a Canis hybrid zone

It is widely recognized that protected areas can strongly influence ecological systems and that hybridization is an important conservation issue. However, previous studies have not explicitly considered the influence of protected areas on hybridization dynamics. Eastern wolves are a species of special concern and their distribution is largely restricted to a protected population in Algonquin Provincial Park (APP), Ontario, Canada, where they are the numerically dominant canid. We studied intrinsic and extrinsic factors influencing survival and cause-specific mortality of hybrid and parental canids in the three-species hybrid zone between eastern wolves, eastern coyotes, and gray wolves in and adjacent to APP. Mortality risk for eastern wolves in areas adjacent to APP was significantly higher than for other sympatric Canis types outside of APP, and for eastern wolves and other canids within APP. Outside of APP, the annual mortality rate of all canids by harvest (24%) was higher than for other causes of death (4-7%). Furthermore, eastern wolves (hazard ratio = 3.5) and nonresidents (transients and dispersing animals, hazard ratio = 2.7) were more likely to die from harvest relative to other Canis types and residents, respectively. Thus, eastern wolves dispersing from APP were especially vulnerable to harvest mortality. For residents, eastern wolf survival was more negatively influenced by increased road density than for other Canis types, further highlighting the sensitivity of eastern wolves to human disturbance. A cycle of dispersal from APP followed by high rates of mortality and hybridization appears to maintain eastern wolves at low density adjacent to APP, limiting the potential for expansion beyond the protected area. However, high survival and numerical dominance of eastern wolves within APP suggest that protected areas can allow rare hybridizing species to persist even if their demographic performance is compromised and barriers to hybridization are largely absent in the adjacent matrix.

Less specific recovery strategy targets for threatened and non-charismatic species at risk in Canada

AbstractRecovery strategies for species at risk have been criticized for a lack of specificity (i.e. measurable and quantifiable criteria) as well as for taxonomic biases, both of which may ultimately affect species’ recovery. However, it is unknown whether the clarity and specificity of written statements within recovery strategies can also influence recovery efforts for certain species at risk. To assess this we examined the variation in semantic uncertainty in the target statements of recovery strategies for Canadian species at risk at the federal and provincial levels. We quantified the lexical density and readability of recovery target statements and examined them for differences according to taxonomic grouping, jurisdiction and degree of endangerment. Recovery statements for the category threatened species had greater semantic uncertainty than those for higher (endangered) and lower (special concern) categories, which is likely to be a function of the fact that threatened species are less abundant than special concern species but are subject to greater errors in population estimates than endangered species. We also found that recovery statements for non-charismatic species (e.g. plants and invertebrates) had greater semantic uncertainty than those for other taxa, which may be related to the resources available for studying and conserving them. Our results suggest a need for greater specificity in recovery targets for threatened and non-charismatic species, and that more focused data collection on these species’ populations is warranted.

Hibernacula Characteristics of Townsend's Big-eared Bats in Southeastern Idaho

ABSTRACT: Townsend's big-eared bat (Corynorhinus townsendii) is a widespread species of special concern that hibernates in large numbers in the lava-tube caves of southeastern Idaho. We measured 24 habitat variables describing landscape-level, physical, and microclimate characteristics of 13 caves and identified at least three that were useful for predicting winter occupancy by C. townsendii. In univariate analyses, distance to ephemeral water was the only variable that significantly predicted occupancy. Temperature and dewpoint were non-significantly higher in occupied than unoccupied caves. Our index of human disturbance was not associated with winter occupancy as observed in other studies. A multivariate (discriminant) analysis identified three characteristics that significantly and best predicted occupancy by big-eared bats in our sample of caves: (1) greater distance to ephemeral water, (2) the presence of a collapse or constriction, and (3) lower mean height. Although not included in our most-predic...

The Role of an Urban Tallgrass Prairie Remnant in Conservation: A Case Study in Central Iowa (USA)

Although more than 85% of Iowa (USA) was covered by tallgrass prairie at the time of settlement by Europeans in the early 19th century, less than 0.1% remains. The Richard W. Pohl State Preserve at Ames (IA) High School, surrounded on three sides by structures, roads, and other development, protects 4 ha of tallgrass prairie. The preserve, commonly referred to as Ames High Prairie (AHP), was grazed but never plowed under private ownership until its acquisition by the Ames School District in 1959. Although considered for development as a parking lot or football field in the 1960s, the residents of Ames voted in 1970 to award The Nature Conservancy (TNC) a 49-year lease to the property (until 2019). This preserve, almost completely open in the 1930s, has been subject to numerous threats, including encroachment by woody plants, entry of non-native and invasive plant species associated with human activity, and erosion associated with storm water runoff, sewer line repair, foot and bike traffic, and major flood events. Recent management activities at AHP, conducted by volunteer land stewards, high school and college students, TNC summer interns, and private contractors, has consisted of controlled burns, cutting and herbicide treatment of encroaching woody plants, manual removal and herbicide treatment of invasive herbaceous plants, and sowing of seeds (collected on site) into reopened areas. Three vascular plant inventories of the 8.9 ha preserve (1966, 1995, current study) have documented the occurrence of 465 taxa (329 native) at AHP, including 5 Iowa special concern species. This flora includes 147 native prairie plant taxa, which ranks 8th in comparison with the 26 other (and mostly larger) prairies protected as state preserves in Iowa. As a vegetation remnant, AHP protects tallgrass prairie taxa and their gene pools, maintains an example of historically abundant (but now scarce) tallgrass prairie vegetation, and provides citizens an opportunity to experience prairie.

Odonata species of special concern for Oklahoma, USA

Assessment of conservation status is a necessary step before management plans can be formulated. Historically such assessments have a strong bias toward vertebrates, particularly endothermic terrestrial vertebrates (i.e. birds and mammals). Invertebrates, by contrast, tend to be ignored, and many insect groups, despite being species rich and reasonably well studied, such as the Odonata (damselflies and dragonflies), have not been assessed or have been assessed only at a broad geographic level (e.g. internationally or continentally). Assessment at a state level recognizes that states often are at the front of regional and local conservation and management planning and implementation. On the basis of our extensive surveys across the Great Plains state of Oklahoma in the central USA, as well as our compilation of thousands of museum specimens dating back to 1877, we were able to discern the status and distribution of each of the 161 species of odonates recorded in the state. In doing so we were able to assess a conservation rank, using NatureServe criteria, for each species. We conclude that nine species are critically imperiled (S1) in the state. These species require immediate conservation attention, initially at the level of intensive surveys to delineate the full extent of the geographic range in the state and to determine the population size and habitat needs. We categorized an additional 13 species as imperiled (S2) and placed 18 species on a “watch list” (S3). Species on these two lists will require field surveys as well, and regions of high occurrence of listed species ought to be targeted for such efforts and considered as set-asides for preservation of key members of the odonate fauna in the state.

Conservation Reliance among California’s at-Risk Birds

Conservation-reliant species require continuing management to ensure their long-term persistence. We qualitatively assessed the extent of conservation reliance for 92 California bird taxa listed under federal or California endangered species acts or recognized as California bird species of special concern. Habitat loss and fragmentation are the major threats for over 90% of these taxa, whereas interactions with predators or brood parasites threaten less than half, and human actions imperil roughly 40%. Some form of habitat enhancement is proposed to reduce the threats for most taxa, reinforcing the value of habitat-conservation strategies. Protecting habitat for wetland taxa and restoring habitat for island taxa appear to be particularly costly actions. Importantly, the species of special concern are every bit as conservation reliant as are taxa listed as endangered or threatened; management of these yet-unlisted taxa may be especially effective in preventing them from slipping into a more precarious status. Consideration of the magnitude of threats together with the degree of conservation reliance may help in prioritizing taxa for conservation. The philosophy and practice of conservation and resource management must recognize that continuing actions will be required to maintain the viability of populations of a great many species.

Genetic and environmental influences on pup mortality risk for wolves and coyotes within a Canis hybrid zone

Eastern wolves (Canis lycaon) are a species of special concern federally in Canada that have hybridized extensively with coyotes (Canis latrans) and gray wolves (Canis lupus) in and adjacent to Algonquin Provincial Park (APP), Ontario. A comprehensive understanding of eastern wolf demography and wolf-coyote hybridization dynamics is needed for informed management, yet no studies have investigated the influence of genetic ancestry and environmental heterogeneity on survival of wolf, coyote, and hybrid pups. We used telemetry, genetic, and environmental data to model and estimate genotype-specific survival and cause-specific mortality of Canis pups (n=159) in eastern and western APP (2002–2011) and the adjacent Wildlife Management Unit 49 (WMU49; 2008–2011). Pup survival was higher in eastern APP (ŝ=0.75) and WMU49 (ŝ=0.61) than in western APP (ŝ=0.25). In APP, mortality risk of pups was primarily influenced by prey availability as lower beaver density in western APP negatively influenced survival and increased starvation risk. Genetic ancestry only influenced pup mortality risk outside of APP with eastern wolf×coyote hybrids surviving poorly relative to other Canis types in WMU49. Poor survival of pups in western APP reduces dispersal from the protected area and decreases the likelihood of expansion of this genetically distinct eastern wolf population beyond APP. Our results advance understanding of wolf and coyote demography as no previous studies have investigated genetic and environmental factors influencing mortality of wolf and coyote pups <4–5months of age with telemetry data.

Bat conservation in China: should protection of subterranean habitats be a priority?

AbstractSubterranean environments are essential for the survival of many bat species and other cave fauna but these places are subject to increasing human disturbance. To examine the significance of subterranean habitats for the conservation of bats in China we surveyed bat species in 225 underground sites during 2003–2011. Our results show that 77% of bat species in China, including 30 nationally Endangered or Vulnerable species and nine endemic species, roost in caves and other subterranean habitats. The number of species in occupied roosts was 1–15. Almost 90% of the roosts surveyed contained signs of human disturbance, most of which was from recreational activities. One hundred and twenty-one roosts merit special concern because they harbour ≥ 6 species or &gt; 1,000 individuals, or species of special concern (threatened or endemic species). Generally, larger roosts support more species and a greater abundance of bats than smaller roosts but there is no direct correlation between the presence of species of special concern and roost size. Disused tourist caves have significantly more bat species than other types of roosts. Our data demonstrate that roost disturbance by recreational activities has pronounced detrimental effects on the number of bat species and the presence of species of special concern. We discuss the social, economic and political issues that could adversely affect bat conservation in caves in China, and we recommend that protection of subterranean habitats should be a high priority for bat conservation.

Use of Genetic Markers to Verify the Distribution of Northern Leopard Frogs (Lithobates pipiens) and Southern Leopard Frogs (Lithobates sphenocephalus) in Kentucky

Understanding species distributions is important for determining whether conservation efforts are necessary. In central Kentucky, an area of potential range overlap occurs between northern leopard frogs (Lithobates pipiens), which is a species of special concern, and southern leopard frogs (L. sphenocephalus). Their distributions are not completely delineated because of their low abundance in central Kentucky and similarity in morphology. Thus, use of genetic markers is necessary for identification. We surveyed for new, and sampled known, populations with a focus on the area of overlap in central Kentucky. We sequenced a portion of the mitochondrial 16S rRNA gene for 55 individuals from 16 populations. Maximum parsimony analysis separated individuals into two completely unresolved lineages representing the two species. Species were distributed as predicted, and no areas of fine-scale overlap were detected, although we did find a population of southern leopard frogs 10 km north-northwest of a northern leopard frog population. It was difficult to find L. pipiens at historically recorded populations, but we documented them in two counties where identification was previously unknown because morphology was intermediate between the species. Although genetic data reliably distinguished the species, they were inconclusive about whether hybridization occurs; future work is necessary to address this question.

Status of northern mountain caribou (Rangifer tarandus caribou) in Yukon, Canada

Caribou (Rangifer tarandus) are an important ecological, cultural and economic resource in Yukon, Canada. Three caribou ecotypes occur within Yukon: Grant’s (R. t. granti), northern mountain (R. t. caribou), and boreal (R. t. caribou). Northern mountain caribou are classified as a species of special concern under Canada’s Species at Risk Act, and a national management plan for northern mountain caribou was recently completed. Twenty-six northern mountain caribou herds occur at least partially within Yukon, representing approximately 30,000 – 35,000 animals. Active monitoring of Yukon’s northern mountain caribou began in earnest in the early 1980s. To date, over 200 fall composition surveys have been carried out, over 1000 animals have been fitted with radio-collars, and nearly 40 formal population estimates have been completed. Disease and contaminant monitoring of these caribou has indicated relatively low disease prevalence and contaminant loading. Northern mountain caribou are harvested in Yukon, with an average of 230 caribou harvested per year by licensed hunters (1995 – 2012) and an unknown number by First Nation hunters. Future challenges related to caribou management and conservation in Yukon include increasing levels of industrial development primarily through mineral exploration and development, ensuring harvest of these herds is conducted sustainably given the absence of total harvest information, inter-jurisdictional management of shared herds, existing uncertainty surrounding herd distribution and delineation, and dealing with vehicle-related mortality of caribou for certain herds. Overall, the population status (i.e., trend) of eight herds is known, with two increasing, two decreasing, and four stable.

The ‘dirty dozen’: socio‐economic factors amplify the invasion potential of 12 high‐risk aquatic invasive species in Great Britain and Ireland

Summary Aquatic invasive species are a growing concern to environmental managers because of their diverse impacts on aquatic biodiversity and high eradication costs, necessitating effective management policies. In this study, we evaluate the ability of environmental and socio‐economic factors to predict the risk of invasion in Great Britain and Ireland of 12 potential aquatic invaders covering all major aquatic groups. Despite their potential to inform risk assessments, this is the first time socio‐economic factors related to propagule pressure have been specifically integrated in distribution modelling. Species distribution models (SDM, MaxEnt algorithm) were calibrated with a set of environmental factors (e.g. bioclimatic, geographical and geological) and integrated with socio‐economic (e.g. human influence index, population density, closeness to ports) predictors. The inclusion of socio‐economic factors in SDM did not affect accuracy scores (AUC already &gt;0·90), but their effects were more pronounced in spatial predictions, resulting in up to a sixfold amplification of the area predicted suitable for each species. Despite the inclusion of potential surrogates of water chemistry (e.g. geology) and propagule pressure (e.g. population density), temperature‐related variables were most important predictors of aquatic species' distributions. According to SDM, the environmental suitability for a suite of invaders belonging to different taxonomic groups and regions of origin is greatest in east and south‐east England and decreases towards the north and west. Multiple invasions in this region are of special concern, as species are known to modify their habitat facilitating subsequent invasions, thereby potentially exacerbating their impacts. Major management regions to be prioritized in monitoring programmes include the Humber, Thames and Anglian River Basin Districts. Species of special concern include a mysid (Hemimysis anomala), a gammarid (Dikerogammarus villosus), a plant (Ludwigia grandiflora) and two crayfishes (Procambarus clarkii and P. fallax). Synthesis and Applications. The inclusion of socio‐economic factors in species distribution models has the potential to improve predictions of areas under a highest risk of multiple invasions and to help disentangle the complex interplay between biological invasions and global environmental and socio‐economic processes. Such understanding is pivotal to prioritize limited resources for the optimum prevention and control of biological invasions.

Establishment of the PalearcticHeterogaster urticae(F.) (Hemiptera: Lygaeoidea: Heterogastridae) in North America, with New British Columbia Records of the NativeH. Behrensii(Uhler)

Abstract. Stinging nettle (Urtica dioica L.; Urticaceae), a Holarctic perennial herb, is a host plant of two lygaeoids of the family Heterogastridae: Heterogaster urticae (F.) in the Palearctic and H. behrensii (Uhler) in the Nearctic Region. We give the first published North American records (other than port-of-entry interceptions) of H. urticae, based on fieldwork in British Columbia in 2010 and 2011. We also give new distribution records for H. behrensii, a species of special concern in the province; it previously was known in Canada only from one site in British Columbia. Morphological characters are provided to distinguish the species. Both heterogastrids were collected from stinging nettle in British Columbia's Lower Fraser Valley and on Vancouver Island; H. urticae also was taken in the Vancouver Metro Area. The species were syntopic in two nettle colonies. We suggest that the heterogastrids'syntopy provides an opportunity to determine whether the adventive H. urticae might adversely affect the nat...

Fish Assemblages in Borrow‐Pit Lakes of the Lower Mississippi River

AbstractBorrow‐pit lakes encompass about a third of the lentic water habitats (by area) in the active floodplain of the Lower Mississippi River, yet little is known about their fish assemblages. We investigated whether fish assemblages supported by borrow‐pit lakes resembled those in oxbow lakes to help place the ecological relevance of borrow‐pit lakes in context with that of natural floodplain lakes. In all, we collected 75 fish species, including 65 species in eight borrow‐pit lakes, 52 species in four riverside oxbow lakes, and 44 species in eight landside oxbow lakes. Significant differences in several species richness metrics were evident between borrow‐pit lakes and landside oxbow lakes but not between borrow‐pit lakes and riverside oxbow lakes. All three lake types differed in fish assemblage composition. Borrow‐pit lakes and riverside oxbow lakes tended to include a greater representation of fish species that require access to diverse environments, including lentic, lotic, and palustrine habitats; fish assemblages in landside oxbow lakes included a higher representation of lacustrine species. None of the fish species collected in borrow‐pit lakes was federally listed as threatened or endangered, but several were listed as species of special concern by state governments in the region, suggesting that borrow‐pit lakes provide habitat for sensitive riverine and wetland fish species. Differences in fish assemblages among borrow‐pit lakes were linked to engineered morphologic features, suggesting that diversity in engineering can contribute to diversity in fish assemblages; however, more research is needed to match engineering designs with fish assemblage structures that best meet conservation needs.

Ecology and Status of the Redbreast Sunfish,Lepomis auritus, in Yoho Lake, New Brunswick

In Canada, Lepomis auritus (Redbreast Sunfish) is only found in southwestern New Brunswick, which is the northern limit for the species. In 1989, The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) listed it as a species of special concern due to its limited distribution, and changed the status to data deficient in 2008. The purpose of our study is to begin to build a database of ecological information for the Redbreast Sunfish in New Brunswick. The most northern population occurs in Yoho Lake. Population estimates averaged 386 from 2005 to 2007. The average total length and weight were 12.5 ± 3.1 cm and 42.6 ± 27.3 g, respectively. The length-frequency distributions were consistent over the years, suggesting a stable population structure. Most adult and juvenile sunfish were observed in areas of dense vegetation and large woody debris. Snorkeling surveys were conducted from late June to early July 2005–2007 to assess timing and habitat preference of spawning Redbreast Sunfish. The nests averaged 52.4 ± 10.1 cm in diameter and were 43.9 ± 12.2 cm deep. Nest substrate was sandy with small gravel, and only 33% of the nests were associated with a physical structure in the water column. Overall, the population of Redbreast Sunfish in Yoho Lake appears to be healthy and stable.

Spatial genetic and morphologic structure of wolves and coyotes in relation to environmental heterogeneity in a Canis hybrid zone

Eastern wolves have hybridized extensively with coyotes and gray wolves and are listed as a 'species of special concern' in Canada. However, a distinct population of eastern wolves has been identified in Algonquin Provincial Park (APP) in Ontario. Previous studies of the diverse Canis hybrid zone adjacent to APP have not linked genetic analysis with field data to investigate genotype-specific morphology or determine how resident animals of different ancestry are distributed across the landscape in relation to heterogeneous environmental conditions. Accordingly, we studied resident wolves and coyotes in and adjacent to APP to identify distinct Canis types, clarify the extent of the APP eastern wolf population beyond the park boundaries and investigate fine-scale spatial genetic structure and landscape-genotype associations in the hybrid zone. We documented three genetically distinct Canis types within the APP region that also differed morphologically, corresponding to putative gray wolves, eastern wolves and coyotes. We also documented a substantial number of hybrid individuals (36%) that were admixed between 2 or 3 of the Canis types. Breeding eastern wolves were less common outside of APP, but occurred in some unprotected areas where they were sympatric with a diverse combination of coyotes, gray wolves and hybrids. We found significant spatial genetic structure and identified a steep cline extending west from APP where the dominant genotype shifted abruptly from eastern wolves to coyotes and hybrids. The genotypic pattern to the south and northwest was a more complex mosaic of alternating genotypes. We modelled genetic ancestry in response to prey availability and human disturbance and found that individuals with greater wolf ancestry occupied areas of higher moose density and fewer roads. Our results clarify the structure of the Canis hybrid zone adjacent to APP and provide unique insight into environmental conditions influencing hybridization dynamics between wolves and coyotes.

Dispatches

Dispatches

Acoustical monitoring of resource conditions in U.S. National Parks

Several laws and derived policy direct the National Park Service to conserve and restore acoustic resources unimpaired for the enjoyment of future generations. The Natural Sounds and Night Skies Division has collected acoustical and related meteorological data at more than 300 sites in over 60 park units spanning the coterminous U. S., with additional sites in Alaska, Hawaii, and American Samoa. Analyses of these data reveal that background sound levels in many park units approach or fall below the human threshold of hearing, and that noise intrusions are ubiquitous. An emergent challenge is to develop efficient tools to reprocess these data to document bioacoustical activity. Generic indices of wildlife activity would be useful for examining responses to climate change, other anthropogenic disturbance, and changes in park unit management. Documentation of individual species occupancy and calling density would inform identification of habitat characteristics and management of species of special concern.

Pathogen and Rodenticide Exposure in American Badgers (Taxidea taxus) in California

Urban and agricultural land use may increase the risk of disease transmission among wildlife, domestic animals, and humans as we share ever-shrinking and fragmented habitat. American badgers (Taxidae taxus), a species of special concern in California, USA, live in proximity to urban development and often share habitat with livestock and small peridomestic mammals. As such, they may be susceptible to pathogens commonly transmitted at this interface and to anticoagulant rodenticides used to control nuisance wildlife on agricultural lands. We evaluated free-ranging badgers in California for exposure to pathogens and anticoagulant rodenticides that pose a risk to wildlife, domestic animals, or public health. We found serologic evidence of badger exposure to Francisella tularensis, Toxoplasma gondii, Anaplasma phagocytophilum, canine distemper virus, and three Bartonella species: B. henselae, B. clarridgeiae, and B. vinsonii subsp. berkhoffii. Badger tissues contained anticoagulant rodenticides brodifacoum and bromadiolone, commonly used to control periurban rodent pests. These data provide a preliminary investigation of pathogen and toxicant exposure in the wild badger population.