bluuebunny/crossref_metadata_2025_split huggingface dataset:
The need for pre‐release health screening in animal translocations: a case study of the Cuban iguana (Cyclura nubila)
Authors: Alberts Allison C. , Oliva Marcie L. , Worley Michael B. , Telford Sam R. , Morris Patrick J. , Janssen Donald L. 
Published: February 2006

AbstractA serious concern with the increasing use of translocation and reintroduction in animal conservation programs is the potential for disease transmission between captive and free‐ranging populations. As part of an experimental headstarting program, 45 juvenile Cuban iguanas, Cyclura nubila, were artificially incubated, maintained in captivity for six to 18 months, and subsequently released into natural areas on the US Naval Base at Guantánamo Bay, Cuba. Prior to release, all animals underwent physical examinations, hematological analyses, plasma biochemical determinations, and blood and fecal parasite screening. Comparable data were collected from free‐ranging juveniles to establish normal baseline values. Although all hematological parameters were within expected ranges for healthy reptiles, captive juveniles exhibited higher total leukocyte counts and percent lymphocytes, but lower percent heterophils, than free‐ranging juveniles. All biochemical values other than lactate dehydrogenase and creatine phosphokinase were within normal ranges. Although higher than reported in other species, these enzymes did not differ in captive and free‐ranging juveniles. Free‐ranging juveniles significantly exceeded captive juveniles in levels of potassium, alkaline phosphatase, lactate dehydrogenase, total protein, cholesterol and triglycerides, whereas the reverse was true for carbon dioxide and glucose. Although free‐ranging juveniles exhibited oxyurids and coccidian oocysts in their feces, captive juveniles were negative for the presence of these parasites. Electron microscopy confirmed that a high percentage of both captive and free‐ranging juveniles possessed erythrocytes infected with the piroplasm Sauroplasma. Implications of these results for successful repatriation of captive‐reared iguanas are discussed.
Female preferences and effective population size
Authors: Blumstein Daniel T. 
Published: February 2006

AbstractAs effective population size (Ne) decreases, genetic factors may become relatively important to a population's or species' persistence. Conservation biologists should be aware of anything that can potentially cause a sudden reduction in Ne. I used simple models to illustrate how certain types of female mating preferences combined with certain types of male traits may lead to a sudden and substantial decrease in Ne. Specifically, if and when there is a sudden ‘downward’ shift in the expression of condition‐dependent male traits, females using fixed‐threshold mate choice criteria might find fewer acceptable males. While mechanisms of female choice remain elusive, a variety of sexually selected traits may be condition dependent. Because the expression of condition‐dependent traits is likely to be impacted by natural or human‐induced environmental changes, behavioral and conservation biologists should pay special attention to them around the mating season. Armed with knowledge of condition‐dependent male traits, it may be possible to minimize the impact on condition‐dependent traits while planning translocations or reintroductions.
Variation in annual estimates of effective population size for San Joaquin kit foxes
Authors: Otten Mark R. M. , Cypher Brian L. 
Published: February 2006

AbstractWe used a demographic model to calculate a series of annual Ne/Nestimates ((Ne/N)S) for a population of the endangered San Joaquin kit fox (Vulpes macrotis mutica) and to identify the demographic parameters explaining significant portions of the variation in (Ne/N)S estimates. Demographic data were collected between 1981 and 1995 from adult kit foxes located on the Naval Petroleum Reserves in California. Demographic parameters were estimated by determining the sex of captured adult foxes and monitoring the survival and reproduction of adult foxes fitted with radiocollars. Individual demographic parameters explaining significant portions (P < 0.10) of the variation in (Ne/N)S estimates was determined using forward stepwise multiple regression. Estimates of (Ne/N)S were highly variable, ranging from 0.22 to 1.15, (
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= 0.67, sem= 0.07, n= 14), with a harmonic mean of 0.55. Forward stepwise multiple regression analysis indicated that mean annual female survival (P= 0.002) and mean annual female reproductive success (P= 0.004) explained significant portions of the variation in estimates of (Ne/N)S, while mean annual sex ratio (P = 0.159), mean annual litter size (P= 0.406) and mean annual male survival (P= 0.922) did not. Long‐term kit fox conservation strategies will probably have to account for wide variation in (Ne/N)S ratios and focus on maintaining or expanding the size and connectivity of populations.
Ecological characteristics of a threatened snake species, Hoplocephalus bungaroides (Serpentes, Elapidae)
Authors: Webb Jonathan K. , Shine Richard 
Published: February 2006

AbstractSpecies with ecological (habitat, dietary) specialization and low reproductive output may be at particular risk from anthropogenic habitat disturbance. We studied growth, reproduction and diet of the threatened broad‐headed snake (Hoplocephalus bungaroides), a small nocturnal elapid from sandstone habitats in south‐eastern Australia. Our data suggest that the life‐history traits and diets of broad‐headed snakes contribute to their vulnerability. Rather than searching actively for prey (like most sympatric elapids), broad‐headed snakes wait under rocks to ambush prey. In consequence, these snakes feed infrequently, grow slowly, mature late and reproduce infrequently (compared with other sympatric snake species). Because of an ontogenetic shift in food habits, populations of broad‐headed snakes require access to high densities of velvet geckos (in rock outcrops) as well as small mammals (in adjacent woodland). The specialized diet, reliance upon two distinctive habitats, low rate of growth, delayed maturation and low reproductive output may have exacerbated the vulnerability of broad‐headed snakes to habitat destruction. All of these traits may be due to the species' reliance upon ambush predation rather than active foraging. A broader analysis supports the hypothesis that foraging mode may contribute to endangerment: a disproportionate number of ‘threatened’ species of Australian elapid snakes rely on ambush predation.
Influence of population isolation on genetic variation and demography in Seychelles warblers: a field experiment
Authors: Komdeur Jan , Kappe Anique , van de Zande Louis 
Published: February 2006

AbstractBetween 1959 and 1968 the entire world population of Seychelles warblers (Acrocephalus sechellensis) comprised only 26–29 individuals entirely confined to Cousin Island (26 ha). Through conservation actions the island population has reached a carrying capacity of ca 320 birds since 1982. The warbler population has significantly lower levels of genetic variation, as determined by multilocus DNA fingerprinting, compared with its mainland relative, the Australian warbler (Acrocephalus australis) and other outbred natural bird populations (mean band sharing coefficients are 0.50, 0.22 and 0.21, respectively), and has a very low annual reproductive rate of 0.28 yearlings per breeding pair. Therefore some degree of inbreeding may have occurred in this population.The relatively low level of genetic variation is not directly responsible for this low reproductive output since breeding pairs that were transferred to the islands of Aride (68 ha) and Cousine (29 ha) with similar vegetation and climate, but with higher year‐round insect food abundance, had significantly higher fecundity and survival. In contrast, no difference in reproductive success was observed between incestuous breeding pairs and non‐incestuous breeding pairs.In addition, annual production of yearlings by pairs on Aride was on average 44 times higher than that by the same pairs on Cousin before the transfer. Annual production of yearlings by pairs on Cousine, that were as inbred as those on Aride, was on average five times higher than that by the same pairs on Cousin before the transfer. Eight years after translocation, the Aride population had grown to over 1000 birds, and six years after translocation, the Cousine population had grown to 186 birds.The experiments, controlled for group size, breeding partner, breeder age and experience, showed that the differences in reproductive success by warblers on the three islands cannot be due to genetic differences because of similar band‐sharing similarities, but seem entirely accounted for by differences in food supply. Although the amount of genetic variation in the Seychelles warblers is relatively low, the demographic parameters do not indicate apparent signs of inbreeding depression in these populations.
Use of simulation models to plan species reintroductions: the case of the bearded vulture in southern Spain
Authors: Bustamante Javier 
Published: February 2006

AbstractI used VORTEX to make a prior evaluation of the planned reintroduction project of the endangered bearded vulture (Gypaetus barbatus) in the mountains of southern Spain. The minimum size of a captive population needed to ensure the release of two bearded vulture fledglings per year is 30 individuals. If breeding success was improved, this minimum captive population could be reduced to 10 individuals. As the cost of the project is proportional to the size of the captive population, some research effort should be devoted to improving breeding success in captivity. The current size of the captive population — four individuals — is not enough to start the releases, even if the vultures were already breeding. The first step for the project should be to increase the size of the captive population. If on average one individual per year was added to the captive population, it would take 15 years to reach 30 individuals. If breeding in captivity was improved, it would take only three to seven years to reach the minimum captive population of 10 individuals. Once releases were started, the project would need on average 20 years to reach a goal of 15 adult pairs in the Cazorla mountains. Both the success of the project and the time necessary to reach this stated goal are very sensitive to the mortality rates in the wild. There is little known about these rates, and better estimates are urgently needed to improve the predictions of the models.
Pairing in mallards and American black ducks: a new view on population decline in American black ducks
Authors: Morton Eugene S. 
Published: February 2006

AbstractData on mating systems suggest that mate choice and dominance advantages by mallard (Anas platyrhynchos) males are not sufficient to explain declines in American black ducks (Anas rubripes). Courtship and pairing of mallards and American black ducks overwintering at a site on the Chesapeake Bay were studied from 1976–1993, during October–March. Mallards declined relative to American black ducks during this period at the study site. Courtship groups and pairs (one exception) consisted of conspecific individuals. Mallards and American black ducks segregated when courting but not when resting. Hybrid males joined courting groups of either species but did not pair successfully with either parental species. Handraised American black ducks hatched from eggs, imprinted on humans, and fledged at the study site, paired with American black ducks even though they were initially the rarer species. Handraised American black ducks avoided pairing with siblings. American black ducks and mallards pair assortatively and hybrids are selected against on the Chesapeake Bay. American black ducks may be declining due to human disturbance rather than due to direct interactions with mallards. Mallards may be increasing because they tolerate human disturbance and through direct release by humans into the American black duck's breeding range.
Unsupervised recognition of individual tigers and snow leopards from their footprints
Authors: Riordan P. 
Published: February 2006

AbstractThis study presents the testing of two unsupervised classification methods for their ability to accurately identify unknown individual tigers, Panthera tigris, and snow leopards, Panthera uncia, from their footprints. A neural‐network based method, the Kohonen self‐organizing map (SOM), and a Bayesian method, AutoClass, were assessed using hind footprints taken from captive animals under standardized conditions. AutoClass successfully discriminated individuals of both species from their footprints. Classification accuracy was greatest for tigers, with more misclassification of individuals occurring for snow leopards. Examination of variable influence on class formations failed to identify consistently influential measurements for either species. The self‐organizing map did not provide accurate classification of individuals for either species. Results were not substantially improved by altering map dimensions nor by using principal components derived from the original data. The interpretation of resulting classifications and the importance of using such techniques in the study of wild animal populations are discussed. The need for further testing in the field is highlighted.
Can artificial brood reduction assist the conservation of yellow‐eyed penguins (Megadyptes antipodes)?
Authors: Efford Murray G. , Edge Kerri‐Anne 
Published: February 2006

AbstractThe yellow‐eyed penguin is a threatened species endemic to New Zealand and its subantarctic islands. Survival and fledging success vary from year to year partly in response to changing food availability. Mortality in ‘poor food’ years may potentially be reduced if adults are allowed to rear only one of their two chicks. Conservation managers have therefore deliberately reduced broods to one in some recent breeding seasons, but the merits of this policy are controversial. We investigated, by simulation modelling, the conditions under which a policy of artificial brood reduction would enhance population growth. Food supply may be difficult to predict from early‐season indicators so we also considered the effect of forecasting errors. Artificial brood reduction can increase the population growth rate, even in the presence of moderate forecasting errors, given a large enough cost of breeding. However, field studies suggest that the required cost of breeding is unrealistically large and the policy is unlikely to be a useful management tool for yellow‐eyed penguins.
Disease as a threat to endangered species: Ethiopian wolves, domestic dogs and canine pathogens
Authors: Laurenson Karen , Sillero‐Zubiri Claudio , Thompson Hal , Shiferaw Fekadu , Thirgood Simon , Malcolm James 
Published: February 2006

AbstractWith increasing awareness of disease as an endangering process, an assessment of which pathogens might pose a problem and their patterns of infection in natural hosts is necessary. This paper examines the exposure of sympatric Ethiopian wolves (Canis simensis) and domestic dogs to canine distemper virus (CDV), canine adenovirus (CAV) and canine parvovirus (CPV) in the Bale region, Ethiopia and then relates these data to population trends of wolves. Wolves (n= 30) sampled between 1989 and 1992 had been exposed to CDV, CAV and CPV, but only CAV might be able to persist in this wolf population. Anecdotal and serological evidence suggested that an epidemic of CDV occurred in the dog population of the Bale Mountains National Park (BMNP) in 1992–93. All park dogs born since this time were seronegative to CDV, although some young dogs in the nearby urban population were seropositive. Despite evidence of CAV infection in wolves, none of the dogs sampled in the park were CAV seropositive, although this virus appeared highly seroprevalent and endemic in urban dogs. All dogs tested for CPV antibodies were seropositive. The BMNP wolf population declined in the late 1980s and early 1990s, with rabies responsible for a dramatic population reduction between 1990 and 1992. Although the population declined further up until 1995, it is not possible to assess whether the concurrent canine distemper epidemic in park dogs also affected wolves. Nevertheless, with evidence of rabies, CDV, CAV and CPV infections in sympatric domestic dogs and Ethiopian wolves, canid diseases clearly pose a significant threat to the future persistence of this Ethiopian wolf population.
Review of DNA‐based census and effective population size estimators
Authors: Schwartz Michael K. , Tallmon David A. , Luikart Gordon 
Published: February 2006

AbstractThe detection of reductions in effective population size (Ne) or census size (Nc) is essential for conservation. Recent developments allow wildlife researchers to obtain genetic material via non‐invasive sampling techniques that may provide the large sample sizes necessary for precise estimates of Ne and Nc. Population genetic theory provides several methods to estimate Ne from allele frequency data: including temporal change in allele frequencies, gametic disequilibrium and heterozygote excess methods. Modification of capture–mark–recapture methods for use with multi‐locus genotype data provides new means for estimating Nc. The combination of new DNA sampling techniques, polymerase chain reaction‐based DNA markers and analytical methods may provide unprecedented power to detect reductions in Ne and Nc of endangered populations. However, these genetic methods are largely untested in the field. We review some relatively unexplored, but promising ways that multi‐locus genetic data can be used to provide important genetic and demographic information and suggest avenues for further research in this area.
Six ecological factors that may limit African wild dogs, Lycaon pictus
Authors: Creel Scott , Creel Nancy Marusha 
Published: February 2006

AbstractAfrican wild dogs (Lycaon pictus) always live at low population densities relative to sympatric large carnivores. This suggests that there are basic ecological reasons for the wild dog's endangered status. We examined the effects of intraspecific and interspecific competition, infectious diseases, foraging success, genetics and human activities on wild dogs. We present data from wild dogs in the Selous Game Reserve, and make comparisons with other populations to identify the limiting factors that are broadly important. The high density of wild dogs in Selous (40 adults/1000 km2) is associated with weak competition from lions and spotted hyenas. Across ecosystems, population density is negatively related to the intensity of interference competition with larger carnivores. Predation by lions and hyenas accounted for 13% of known‐cause deaths in Selous and 33–50% in other populations. Intraspecific competition caused 69% of known‐cause deaths in Selous, through infanticide and fights between packs, although most of the victims were juveniles with low reproductive value. Infectious diseases had little apparent impact in Selous (4% of deaths) or Kruger National Park (5%), but did play a role in the extinction of a small population in Serengeti. Infectious diseases and competition will generally interact because competitors harbor and transmit the diseases that affect wild dogs. Human activities caused 12% of deaths in Selous, even though it is large (43 000 km2) and does not border large human or livestock populations. Humans were the major agent of mortality in some populations. Foraging success varied little across ecosystems and was not apparently limiting. Mitochondrial DNA (mtDNA) genotypes revealed clinal variation between Selous and distant populations (rather than geographically isolated subspecies, as previously suggested). All wild dog populations have a genetically effective size (Ne) less than 500, so gene flow is necessary to maintain genetic diversity within populations.
Population dynamics of the endangered Cape Sable seaside‐sparrow
Authors: Curnutt John L. , Mayer Audrey L. , Brooks Thomas M. , Manne Lisa , Bass Oron L. , Fleming D. Martin , Nott M. Philip , Pimm Stuart L. 
Published: February 2006

AbstractThe Cape Sable seaside‐sparrow (Ammodramus maritimus mirabilis) has disappeared from its only known breeding areas episodically since its discovery early this century. Systematic surveys across its range in the southern Everglades find the sparrow's range to be fragmented into six subpopulations. The sparrow population decreased by 58% between 1992 and 1995, with the near extinction of the western half of the population and the temporary local extinction of some eastern populations. Other similar grassland sparrows have populations that vary considerably from year to year. Yet the decline in the western subpopulation and the local extinction of some of the peripheral populations cannot be explained by natural variability alone. Hurricane Andrew passed over several subpopulations prior to the particularly poor year of 1993. However, the geographical and temporal patterns of subpopulation decline are not consistent with what would be expected following a hurricane. Frequent fires prevent successful breeding as does flooding during the breeding season. Better management can prevent frequent fires and episodic flooding. However, the long‐term survival of the sparrow depends on managing the unanticipated risks that attend its small, fragmented population.
Water levels, rapid vegetational changes, and the endangered Cape Sable seaside‐sparrow
Authors: Nott M. Philip , Bass Oron L. , Fleming D. Martin , Killeffer Stephen E. , Fraley Nancy , Manne Lisa , Curnutt John L. , Brooks Thomas M. , Powell Robert , Pimm Stuart L. 
Published: February 2006

AbstractThe legally endangered Cape Sable seaside‐sparrow (Ammodramus maritimus mirabilis) is restricted to short‐hydroperiod, marl prairies within Florida's Everglades National Park and Big Cypress National Preserve. Marl prairies are typified by dense, mixed stands of graminoid species usually below 1 m in height, naturally inundated by freshwater for 3–7 months annually. Water levels affect the birds directly, by flooding their nests, and indirectly by altering the habitat on which they depend. Managed redistribution of water flows flooded nearly half of the sparrow's geographical range during several consecutive breeding seasons starting in 1993. Furthermore, these high water levels rapidly changed plant communities, so jeopardizing the sparrow's survival by reducing the availability of nesting habitat.
Osteological corroboration of pathological stress in a population of endangered Florida pumas (Puma concolor coryi)
Authors: Duckler Geordie L. , Van Valkenburgh Blaire 
Published: February 2006

AbstractThe Florida panther, Puma concolor coryi, is a subspecies on the verge of extinction. Recent field studies have shown the dwindling population to be suffering from numerous physical problems manifest in their soft tissues. Here we explore the skulls and skeletons of more than 50 P. concolor coryi for corroborative evidence of poor condition such as tooth fracture, arthritis, infection, trauma, and lines of arrested growth (Harris lines). Results are compared with those for an osteological collection of presumed healthy pumas from outside Florida. Although the two samples did not differ significantly in the relative prevalence of most of the pathologies, the Florida cats fractured their teeth more often and exhibited significantly more lines of arrested growth in their long bones. The greater number of teeth broken in life is associated with heavier tooth wear among Florida panthers and a diet depauperate in large prey. The elevated incidence of Harris lines is probably a result of more regular episodes of poor nutrition in the Florida population. Our results demonstrate that the study of osteopathologies is a new tool for the conservation biologist and highlight the value of preserving entire skeletons, as has been done for P. concolor coryi.