bluuebunny/crossref_metadata_2025_split huggingface dataset:
Estimating the demographic effective population size of the Saimaa ringed seal (Phoca hispida saimensis Nordq.)
Authors: Kokko Hanna , Lindström Jan , Ranta Esa , Sipilä Tero , Koskela Jouni 
Published: February 2006

AbstractA common ‘rule of thumb' in conservation biology is that populations of more than 100 individuals are not threatened by demographic stochasticity alone. However, the effect of demographic stochasticity on population survival may be strengthened if the population has a non‐homogeneous demography. A recently developed measure, the demographic effective population size ND, scales population size by taking the differential contribution of individuals into account. We exemplify the estimation of ND with the current population of the Saimaa ringed seal, comprising about 200 individuals. The estimate of ND is shown to be dependent on how independently individuals can be assumed to reproduce. Completely independent reproduction leads to ND∼ 250, suggesting a safe future for the population. However, when acknowledging the potential of breeding failure due to habitat limitation and difficulties of dispersal among the different subareas of Lake Saimaa, ND lies in an alarming range from six to 30 individuals. The effective means to increase the ND value are limited. Although subdivision itself decreases the value of ND, improving dispersal of individuals is shown to be of limited aid. Instead, the most effective way to enhance future prospects of the Saimaa seal population is to improve pup survival to maturity.
Description of Muntiacus truongsonensis, a new species of muntjac (Artiodactyla: Muntiacidae) from Central Vietnam, and implications for conservation
Authors: Giao P. M. , Tuoc D. , Dung V. V. , Wikramanayake E. D. , Amato G. , Arctander P. , MacKinnon J. R. 
Published: February 2006

AbstractA small blackish muntjac has been discovered in the west Quang Nam province of Vietnam. DNA sequencing of six individuals showed that this is a distinct species. A description is given. The new find is the third new ungulate species to be discovered in Vietnam in five years. The paper predicts that more species remain to be found in the Annamite mountain range and includes DNA analysis from two more undescribed species. The DNA analysis indicates that there has been a radiation of several related muntjac species in the Annamite mountains, also that the new truongson muntjac shows high intraspecific genetic diversity indicative of a large effective population size. The paper discusses the significance of these finds from an evolutionary and conservation viewpoint. The authors urge conservation authorities in the IndoChinese countries to devote special measures to protect this site of dynamic evolution which retains a combination of relict endemics (e.g. Pseudoryx) as well as on‐going speciation.
A new species of muntjac, Muntiacus putaoensis (Artiodactyla: Cervidae) from northern Myanmar
Authors: Amato George , Egan Mary G. , Rabinowitz Alan 
Published: February 2006

AbstractA new species of barking deer (Muntiacus spp.) is described from northern Myanmar. Diagnostic DNA character data are presented along with preliminary information on morphology, distribution, and phylogenetic relationships. This discovery contributes significantly to our knowledge of this poorly studied group and highlights the importance of continued field surveys in remote regions. Similar studies have resulted in a significant increase in conservation efforts in other parts of South‐east Asia, and argue for additional conservation efforts for this region.
Male‐producing thermal ecology of a southern loggerhead turtle nesting beach in Brazil: implications for conservation
Authors: Baptistotte Cecília , Scalfoni Juarez T. , Mrosovsky N. 
Published: February 2006

AbstractThe major nesting areas for loggerhead turtles in Brazil are estimated to produce about 90% female hatchlings on account of their warm temperatures. In the present study, sand temperatures were monitored at the southern cooler end of the nesting range (Comboios, Espiríto Santo): the temperatures were cool enough to produce a far greater proportion of males than at the major beaches further north. Particular beaches may be thermally suited for the production of a particular sex. Protection of rookeries that appear minor in terms of numbers of turtles nesting could be important for the health of a larger population by insuring that there is an appropriate sex ratio. Temperatures were also monitored in a central guarded hatchery, set back from high seas. The hatchery was thermally similar to zones on the beach where turtles commonly lay, indicating that this conservation practice is unlikely to introduce any large distortions of sex ratio on this beach.
Comparison of the population viability analysis packages GAPPS, INMAT, RAMAS and VORTEX for the whooping crane (Grus americana)
Authors: Brook Barry W. , Cannon John R. , Lacy Robert C. , Mirande Claire , Frankham Richard 
Published: February 2006

AbstractPopulation viability analysis (PVA) is widely used in conservation biology to compare management strategies and predict probabilities of extinction for endangered species. However, it remains unclear whether the available range of generic PVA programs produce similar predictions when applied to common data sets. A comparative analysis was carried out using six commonly applied PVA packages (GAPPS, INMAT, RAMAS Age, RAMAS Metapop, RAMAS Stage and VORTEX), based on the extensive population data available for the endangered whooping crane, Grus americana. Significant differences were found between the projections of the PVA packages. In particular, the introduction of stochastic variation in breeding structure led to large differences between some packages. Surprisingly, two versions of VORTEX produced very different predictions due to a subtle difference in the way monogamous breeding was modelled. The pattern of similarities and differences among the projections of the packages differ depending on the species examined. In contrast to the predictions of comprehensive (realistic) models, simplified (standardized) models were found to be relatively congruent, which probably reflects similarities in the fundamental biological processes being modelled by the PVA packages. The implications for conservation are clear; caution must be exercised when interpreting the projections of a model built using any one PVA package since, due to seemingly subtle differences in what biological assumptions and threatening processes are included in the models, the predictions among PVA packages (or versions of the same program) are not necessarily concordant.
Microsatellites identify introduced New Zealand tammar wallabies (Macropus eugenii) as an ‘extinct’ taxon
Authors: Taylor A. C. , Cooper D. W. 
Published: February 2006

AbstractThe range of the tammar wallaby (Macropus eugenii) has decreased substantially in Australia in recent times. Because two introduced populations in New Zealand may have descended from a now‐extinct Australian population(s), we investigated their origins using a novel approach. We combined data from seven highly polymorphic microsatellite markers with simulation modelling to infer the history and conservation value of the New Zealand populations. The microsatellite alleles in one New Zealand population (Rotorua) are merely a subset of those in the other (Kawau Is.), suggesting Rotorua had no immigrants from an independent source. However, in the Kawau Is. population (sample size 33–37), 37 alleles were absent that were present in the Kangaroo Is. (South Australia) population at frequencies ranging from 1–40%. The probability of those alleles being lost during a founding event from Kangaroo Is. was investigated using a program that simulates the genetic consequences of population size bottlenecks. Use of realistic bottleneck parameters resulted in probabilities approaching zero that the observed allele deficiencies in the Kawau population could have occurred randomly, identifying the New Zealand tammar wallabies as descendants of a distinct taxon that is no longer extant in Australia.
Identification of domestic cattle hybrids in wild cattle and bison species: a general approach using mtDNA markers and the parametric bootstrap
Authors: Ward Todd J. , Bielawski Joseph P. , Davis Scott K. , Templeton Joe W. , Derr James N. 
Published: February 2006

AbstractMany species are currently undergoing reductions in population size due to widespread habitat loss and expanding human activities. Because interspecific hybridization is often a consequence of population decline and fragmentation, identification of individuals or populations with hybrid ancestry is an increasingly important issue in conservation biology. In many wild cattle and bison species, the problem of natural hybridization has been compounded by indiscriminate crossbreeding with domestic cattle for the purpose of improving domesticated stocks. Therefore, a genetic test using the polymerase chain reaction was developed so that wild cattle and bison with domestic cattle mitochondrial DNA (mtDNA) haplotypes could be rapidly identified. Using this genetic test, domestic cattle mtDNA haplotypes were detected in Bos grunniens (yak), Bison bonasus (European bison), and 6 out of the 15 (40%) Bison bison (North American bison) populations tested. In total, 30 out of the 572 (5.2%) North American bison tested, were found to have domestic cattle mtDNA. The hybrid origin of these mtDNA haplotypes was verified in a phylogenetic analysis using the parametric bootstrap. These results are discussed in terms of their implications for the conservation status and future management of wild cattle and bison species.
Biological and technical considerations of carnivore translocation: a review
Authors: Miller Brian , Ralls Katherine , Reading Richard P. , Scott J. Michael , Estes James 
Published: February 2006

AbstractCarnivore translocations are usually risky and expensive, and a number of biological and non‐biological factors can influence success. Biological considerations include knowledge of genetics, demographics, behavior, disease, and habitat requirements. This information is critical for determining if the translocation should be attempted, if it could be successful, and how it could be implemented in an efficient and effective manner. We stress that individual species will vary in their responses, and ideas should be tested scientifically. The technical considerations of translocation are closely related to the biological questions. They include legal framework, fiscal and intellectual resources, monitoring capacity, goals of the translocation, logistic challenges, and organizational structure of decision‐making. We do not discuss socio‐economic aspects of translocation because those challenges require detailed discussion in a separate paper. We suggest that because large carnivores often play key roles in regulating ecological interactions between trophic levels, restoring them is more than a single‐species activity. By restoring carnivores in viable numbers, we can take a large step toward recovering ecological integrity of geographically extensive landscapes.
Belding's yellowthroat: current status, habitat preferences and threats in oases of Baja California, Mexico
Authors: Rodríguez‐Estrella Ricardo , Delgado Laura Rubio , de Bonilla Esteban Pineda Diez , Blanco Guillermo 
Published: February 2006

AbstractThe Belding's yellowthroat (Geothlypis beldingi) is an endemic species of Baja California Sur confined to the edge vegetation of freshwater at several oases. Information on its current status, distribution and habitat selection, and an analysis of the human‐related threats that the species faces at 10 oases are given here. Belding's yellowthroats have disappeared from three historical sites, Santiago, Miraflores and El Triunfo, where they were recorded in the early 1900s. Belding's yellowthroats forage mainly in reed grass and cattails in all oases and were never recorded > 50 m outside the edge vegetation of the water. The main threats we detected to their habitat were cutting of reed grass for rural home construction, burning vegetation, opening trails to the water for cattle, overgrazing of reed grass by horses and burros, and using up the water for agricultural and tourism purposes. Although local populations of the species seem to be common, they are vulnerable because the distribution of the species in southern Baja California is patchy. Populations are in general small and isolated, the bird has habitat‐specific requirements, and human‐related activity is putting pressure on the habitat of this endemic species. A Multidimensional Scaling Analysis showed that southern populations are likely to be more severely affected than northern ones.
Microsatellite heterozygosity, fitness and demography in natterjack toads Bufo calamita
Authors: Rowe G. , Beebee T. J. C. , Burke T. 
Published: February 2006

AbstractRelationships between mean individual fitness and genetic heterozygosity remain controversial because multiple studies over many years have yielded inconsistent results. However, molecular measurements of genetic variation have mostly been based on allozyme markers, which may have substantial limitations due to their relative insensitivity and occasionally also to the effects of natural selection. We investigated variation in the number of tandem dinucleotide repeats at eight polymorphic microsatellite loci in 38 natterjack toad, Bufo calamita, populations that varied in census size, degree of isolation and distance from the distributional range edge. We also measured fitness attributes, notably larval survival and growth rates, under standardized conditions using samples from six of these populations. The results indicated that larval growth rates were positively and strongly correlated with expected heterozygosity (He) across the microsatellite loci. He was in turn highest in large populations with minimal isolation, but low near the biogeographical range edge irrespective of population size. Larvae from the smallest and most isolated natterjack population exhibited particularly low fitness and heterozygosity. Our results suggest that microsatellite loci may provide a valuable new approach in studies of links between fitness and heterozygosity.
Protected areas and the conservation of grouse, partridges and pheasants in east Asia
Authors: McGowan Philip , Chang‐qing Ding , Kaul Rahul 
Published: February 2006

AbstractGrouse, partridges and pheasants belong to the highly threatened avian order Galliformes. We collected together existing data on the distribution of these species in east Asia (China and Pakistan south and east to the Lesser Sundas in Indonesia and Palawan in the Philippines) from published and unpublished sources. From this we extracted 1068 records of 101 east Asian endemics (plus three other species that have been found in east Asian protected areas) in 369 protected areas. One species was found in 108 protected areas and a further two in 39 and 38 protected areas: six species were not known from any. Of the threatened endemics, 84% were recorded in 10 or fewer protected areas compared with 50% of endemic species that are non‐threatened. A near‐minimum network designed to include each species in three protected areas wherever possible comprised 49 irreplaceable sites and 33 others. Comparison with other studies should indicate which of these protected areas are also important for other groups of organisms, such as plants and swallowtail butterflies. There is a need for improvement in knowledge of occurrence in protected areas. This should be provided from further collation of existing information and from undertaking targeted surveys. There is also a need to consider which protected areas are suitable for inclusion in a network and how many such areas are required to ensure that each species is adequately represented.
Translocations and rapid evolutionary responses in recently established populations of western mosquitofish (Gambusia affinis)
Authors: Stockwell Craig A. , Weeks Stephen C. 
Published: February 2006

AbstractThe response of quantitative traits in translocated populations has not been well explored. Evolutionary shifts in quantitative traits, such as life history characteristics, are of particular interest because of their obvious association with fitness. In a recent survey, Stockwell (1995) examined life history variation of four populations of western mosquitofish (Gambusia affinis) that were derived from a common ancestral population 55–58 years earlier. Three life history traits differed considerably among the four sites and appeared to be correlated with local environmental conditions. To test whether these differences were due to plasticity or rapid evolution, fish from the four sites were maintained under common‐garden conditions for two generations. After two generations a genetic basis was inferred for two of the three traits (size at maturity and fat content), but not for the third trait (offspring size). Thus, rapid evolution had occurred for two life history traits in these recently established populations. This case of rapid life history evolution may be due to genetic drift and/or natural selection. These data suggest that translocations may lead to rapid evolutionary responses of targeted taxa. Rapid evolutionary responses are of special concern for ‘refuge’ populations that are maintained as a hedge against extinction.
Modelling the distribution of red squirrels (Sciurus vulgaris) on the Isle of Wight
Authors: Rushton S. P. , Lurz P. W. W. , South A. B. , Mitchell‐Jones A. 
Published: February 2006

AbstractWe investigated the distribution of red squirrel (Sciurus vulgaris) populations on the Isle of Wight using Generalized Linear Models (GLMs) and a spatially explicit population dynamics model (SEPM) with the aim of identifying management options for red squirrel conservation. The presence/absence of red squirrels in habitat blocks in the landscape was used as the dependent variable and the size and separation of habitat blocks as independent variables in the GLM analysis. Red squirrel presence within a woodland was significantly related to woodland size and the distance to the nearest wood known to contain squirrels. The SEPM‐generated predictions on population viability were closest to the field data when a low dispersal distance of 1 km was used. This suggests that squirrel dispersal on the Isle of Wight is restricted. Our results suggest that some large interconnected woodlands should be maintained if red squirrels are to be conserved for the future.
Testing for inbreeding and outbreeding depression in the endangered Gila topminnow
Authors: Sheffer Ruby J. , Hedrick Philip W. , Velasco Anthony L. 
Published: February 2006

AbstractThe extent of inbreeding and outbreeding depression is thought to be a fundamental factor influencing the long term persistence of an endangered species. However, there have been no comprehensive examinations of either factor in an endangered species, except for a mouse species. Here we examined both the extent of inbreeding and outbreeding depression for five traits related to fitness in populations from the four watersheds in which the endangered Gila topminnow (Poeciliopsis o. occidentalis) still exists in the USA by making experimental matings with replicate samples and simultaneous controls. There was generally high survival, similar body size, and little bilateral asymmetry for all the inbred and outbred matings for all populations, i.e. there was no evidence of either inbreeding or outbreeding depression for these traits. Similarly there was no evidence of inbreeding or outbreeding effects for fecundity or sex ratio except for the sample from Monkey Spring, which had highly skewed (female‐biased) sex ratios after one generation of inbreeding. In addition, brood sizes for Sharp Spring declined over time in inbred lines maintained by full‐sib mating. These results further support the suggestion, based on molecular genetic analysis and considerations of habitat differences, that Monkey Spring be considered an evolutionarily significant unit, distinct from the remainder of existing populations. Potential explanations for the results and their implications for conservation are discussed.
Detecting inbreeding depression is difficult in captive endangered species
Authors: Kalinowski Steven T. , Hedrick Philip W. 
Published: February 2006

AbstractDuring the past two decades, pedigree analysis has documented inbreeding depression in many captive populations. This and subsequent research has led to a recognition that inbreeding depression is a potentially important determinate of small population fitness, in both captivity and the wild. Modern captive‐breeding programmes now universally avoid inbreeding. We use simulation to investigate how much traditional pedigree analysis will reveal about the effect of inbreeding in such populations. We find that pedigrees typical of breeding programmes designed to avoid inbreeding have low statistical power to detect inbreeding depression.
How many to dehorn? A model for decision‐making by rhino managers
Authors: Milner‐Gulland E. J. 
Published: February 2006

AbstractA stochastic dynamic programming model is presented for decision‐making by the manager of a small rhino reserve facing a poaching threat, with the objective of maximizing the rhino population size in the long term. The manager decides annually what proportion of the budget to spend on dehorning as opposed to law enforcement. Poacher incentives depend on revenues from illegal horn sales, which are related to the manager's decisions through the mean horn size of the rhino population (affected by spending on dehorning). Poacher incentives also depend on hunting costs, which are related to the manager's decisions through the risk of capture and punishment (affected by spending on law enforcement). The results suggest that, at realistic parameter values, the optimal strategy is to dehorn as many rhinos as possible annually except at very low rhino population sizes, budgets or mean horn sizes. The simple strategy of dehorning annually regardless of population size or mean horn size gives very similar results to the optimal strategy. Other potential strategies (such as dehorning only half the rhinos each year) performed badly. Selling horns and reinvesting the proceeds in rhino conservation did not provide enough revenue to significantly increase rhino population sizes.
Retention of reproductive barriers and ecological differences between two introduced sympatricMacropusspp. in New Zealand
Authors: Taylor A. C. , Sunnucks P. , Cooper D. W. 
Published: February 2006

AbstractIn their native Australia, tammar (Macropus eugenii) and parma (M. parma) wallabies are allopatric and differ markedly in habitat use, social structure and degree of reproductive synchrony. They occur sympatrically only on Kawau Is., New Zealand, as a result of introductions last century. Reproductive data collected from wallabies on Kawau Is. in April 1996 show thatM. eugeniimaintains high reproductive synchrony whileM. parmaremains asynchronous. Both species show sexual dimorphism and differences in habitat use as seen in Australia. In additionM. parmais more solitary, and is frequently found in closed‐canopy woodland, whileM. eugeniitends to aggregate in open grassy clearings. Thus the species maintain broad reproductive and biological distinctions, despite enforced sympatry in a novel environment. Highly‐resolving genetic (microsatellite) data reveal no evidence for hybridization. This is essential information given the known (M. eugenii) or likely (M. parma) high conservation value of New Zealand stocks. Kawau Is. is the only predator‐free site withM. parma, a species whose persistence in Australia is threatened by fox predation. Finally, we use data on mitochondrial cytochromebsequence divergence amongst severalMacropustaxa to demonstrate close agreement with degree of reproductive isolation.