bluuebunny/crossref_metadata_2025 huggingface dataset:
Biological and logistical explanations of variation in wolf population density
Authors: Fuller T. K. , Murray D. L.
Published: February 2006

In a study correlating carnivore density with study area size, Smallwood & Schonewald (1996) suggested that for larger areas, biologists extrapolate from small, high‐density study sites to many unstudied low density sites, but that this approach is invalid because of heterogeneous distribution of animals across the landscape. For wolves (Canis lupus), however, size of study areas may also be a consequence of density. Linear regression of data from 18 recent field studies of wolves indicates that study area size is correlated less strongly to mean numbers of wolves counted in an area (r2=0·24) than to wolf density (r2=0·85). When parameters representing biological features of each study area (average wolf pack territory size, ungulate biomass density index and predominant ungulate species), as well as logistical constraints of the study (number of packs), were made available for inclusion through a stepwise procedure, mean numbers of wolves counted were related (r2=0·94) to number of packs, ungulate biomass and deer, while density was related to both study area size and number of wolves counted (r2=0·91). Study area size was found to be strongly predicted (r2=0·96) by ungulate biomass, wolf territory size and wolf numbers. These results clearly reinforce the idea that biological parameters play an essential role in determining animal numbers and density. It also follows, as emphasized by Smallwood & Schonewald (1996, in press), that extrapolation of census or survey information to larger areas needs to be done carefully to account for actual variation in animal density.
Bats and insects over two Scottish rivers with contrasting nitrate status
Authors: Racey Paul R. , Swift Susan M. , Rydell Jens , Brodie Laura
Published: February 2006

The abundance of foraging bats (Pipistrellus pipistrellus and Myotis daubentonii) and flying insects over two rivers in north‐east Scotland (Dee and Ythan), differing eightfold in nitrate levels, were compared by paired samples over three periods in summer 1995, during each of which 10 nights' sampling was undertaken using ultrasonic detectors and insect suction traps. Thirteen out of the 18 pairwise comparisons of bat passes, insect numbers, biomass and diversity were not significantly different. The oligotrophic Dee supported higher numbers of bats than the eutrophic Ythan in June, but this was attributed to an effect of adverse weather conditions affecting the Ythan. In July and August–September, neither bat abundances nor the abundance of Chironomidae and Trichoptera, the main food of the bats, differed significantly between the two rivers, although the Ythan showed higher total insect biomass than the Dee. The Ythan also showed a much higher abundance of small Diptera, mainly Psychodidae and Cecidomyiidae, associated with elevated nitrogen levels in the intensively farmed river valley. Thus a small eutrophic river can support as many bats and as high an insect density as a large oligotrophic one.
Genetic evidence for two evolutionarily significant units of White Sands pupfish
Authors: Stockwell Craig A. , Mulvey Margaret , Jones Adam G.
Published: February 2006

White Sands pupfish (Cyprinodon tularosa) are endemic to southern New Mexico and occur in only four localities: Malpais Spring, Salt Creek, Mound Spring and Lost River. Recently reported historical accounts indicate that the latter two populations were derived from translocations. Their limited distribution and complicated history suggest that knowledge of population genetic structure would be useful for the development of a sound conservation strategy. Mitochondrial DNA (mtDNA) sequences for a segment of the control region showed little variation. Variation was observed for microsatellite and allozyme loci with 37% attributable to divergence among populations. The mean genetic distance between Malpais Spring and the other three populations was high (allozymes: Darc= 0.541; microsatellites: Rst= 0.684) compared with the mean distance among the other three populations (Darc=0.161, Rst=−0.016). There were fixed or nearly fixed differences in allele frequency between the Malpais Spring population and the other three populations at one allozyme locus (hexokinase) and two microsatellite loci (WSP‐02 and WSP‐11). We suggest the recognition of two evolutionarily significant units (ESUs) for the White Sands pupfish: Malpais Spring and Salt Creek. Our data indicate that the Lost River and Mound Spring populations descended from translocations from the Salt Creek population. Therefore, conservation efforts should focus on the Malpais Spring population.
A long‐term systematic approach to planning reintroductions: the Persian fallow deer and the Arabian oryx in Israel
Authors: Saltz David
Published: February 2006

A long‐term systematic approach to planning the reintroduction of Persian fallow deer (Dama dama mesopotamica) and Arabian oryx (Oryx leucoryx) in Israel is presented. The reintroductions rely on local breeding‐cores that are at their holding capacity of 150 deer and 80 oryx. The approach is based on three elements: (1) maximizing the number of animals that can be withdrawn from a permanent breeding core for the purpose of reintroduction using ‘maximum sustained yield’ (MSY) techniques; (2) determining a priori, using rules‐of‐thumb (such as IUCN Red List Categories), preliminary criteria for project completion; and (3) estimating the time it would take the reintroduced populations to meet the criteria for project completion. I used Monte Carlo Leslie matrix growth models to determine MSY and to project the growth of the reintroduced population. Based on these simulations, the MSY for the fallow deer breeding‐core is 15 adult females in the first year and 12 adult females/year thereafter. The oryx breeding‐core can yield 12 adult females during the first year and 16 adult females every third year thereafter. Project completion was preliminarily set to a wild population of 250 adult deer and 100 adult oryx. The simulations predict that it will take 8–11 years to complete the fallow deer reintroduction and 6–10 years to complete the oryx reintroduction. Post‐release monitoring will help improve the data used in the model and permit re‐assessment of the criteria for project completion.
Impact of poaching on an Asian elephant population in Periyar, southern India: a model of demography and tusk harvest
Authors: Sukumar R. , Ramakrishnan Uma , Santosh J. A.
Published: February 2006

Ivory poaching has been a serious problem in Asian elephant (Elephas maximus) populations. Reliable records of elephants killed and ivory harvested are generally unavailable. We have used a simulation modelling approach to estimate the numbers of male elephants killed and the quantities of ivory harvested over a 20 year period (1974–94) in the Periyar Reserve of southern India. The age‐structured Leslie matrix projection model was modified for this purpose by considering three segments (female, tusked male and tuskless male), relating fecundity to adult sex ratio and iteratively simulating tusked male mortality rates so as to match the observed elephant population structure at Periyar. Four different scenarios of poaching all gave very similar results. We estimate conservatively that 336–388 tuskers have been poached and 3256–3334 kg of ivory harvested by poachers over the 20 year period. The maximum harvest came from the 10–20 year age class. Trends in various demographic parameters such as population numbers, tusked male to tuskless male ratios and female fecundity are described. The implications of ivory poaching and the extremely skewed sex ratios for the conservation and management of the elephant population at Periyar are discussed.
Behavioural ecology in managed reserves: gender‐based asymmetries in interspecific dominance in African elephants and rhinos
Authors: Berger Joel , Cunningham Carol
Published: February 2006

As large‐bodied mammals become restricted to progressively smaller fragments of former habitat, competitive interactions and interspecies aggression are likely to intensify. Data on the outcomes of 159 encounters between endangered African pachyderms revealed that: (1) female elephants (Loxodonta africana) dominated both sexes of black rhinos (Diceros bicornis); and (2) rhino males but not females displaced elephant bulls. The results of an additional 127 interactions involving pachyderms and 12 additional mammals ranging in size from cheetahs (Acinonyx jubatus) to giraffe (Giraffa camelopardalis) indicates that females of either pachyderm deny immediate access to limited resources. Although the evolution of gender‐specific asymmetries in interspecific dominance has received little formal study, it may best be explained by understanding patterns of parental investment; however, from a conservation perspective, one consequence of size‐related dominance is that with continued containment of elephants and rhinos in managed reserves, the most handicapped species are likely to be the smaller ones.
Phylogeographic uniformity in mitochondrial DNA of the snapping turtle (Chelydra serpentina)
Authors: Walker DeEtte , Moler Paul E. , Buhlmann Kurt A. , Avise John C.
Published: February 2006

Previous studies have revealed considerable genetic variation, geographic localization, and genealogical depth for mitochondrial DNA (mtDNA) haplotypes within each of several species of freshwater turtles in the south‐eastern United States of America. Here we report a notable exception to such phylogeographic patterns. In control‐region sequences of 66 snapping turtles (Chelydra serpentina) collected from 10 south‐eastern states, a single mtDNA haplotype predominated and the two rare variants detected were nearly identical to the common genotype. This pattern of low mtDNA variation and a lack of appreciable geographic population structure is extremely unusual for a widely distributed animal species. For purposes of taxonomy and conservation, these findings suggest the presence of only one ‘evolutionarily significant unit' for C. serpentina in this otherwise phylogeographically rich region of the country. Possible explanations for this phylogeographic pattern in the snapping turtle are considered.
How large must populations be to retain evolutionary potential?
Authors: Franklin I. R. , Frankham R.
Published: February 2006

Maintaining genetic variation for future evolutionary change is an important issue for conservation biology. However, there is controversy over the effective population size (Ne) required for endangered species to retain their evolutionary potential, with proposed sizes ranging from 500 to 5000. The highest estimate is based on the assumption that 90% of mutations are deleterious. We review the arguments for an effective size of 5000 and conclude that it assumes effective mutation rates that are too low, and heritabilities that are, in general, very high. We conclude that an Ne of 500–1000 is appropriate at this time.
Population differentiation and conservation of endemic races: the butterfly, Plebejus argus
Authors: Thomas C. D. , Glen S. W. T. , Lewis O. T. , Hill J. K. , Blakeley D. S.
Published: February 2006

Five races of the Eurasian silver‐studded blue butterfly, Plebejus argus, are restricted to different habitats in north Wales and north‐west England. One of these races is extinct, and others are threatened. The four extant forms differ in morphology, habitat, host plant choice, performance on different host plant species and species of associated ant. Some of these differences are maintained in captivity, suggesting evolutionary divergence. Different races with different habitat requirements require different practical conservation management to maintain existing populations and metapopulations. Between‐population, or racial, variation is an important consideration in the development of conservation programmes for this and other threatened species. Racial differentiation in P. argus suggests relatively long periods of isolation in particular habitats; the same areas contain other rare species and races. Many countries support the principle of conserving genetic variation within species, but practical methods do not exist for recognizing key areas to prioritize. We suggest that the existence of local races of well‐known taxa may be used to indicate biodiversity hotspots, at a taxonomic level below that of full species. These may represent key locations for the conservation of genetic bio‐diversity.
Identification of evolutionary significant units in the Spanish wild goat, Capra pyrenaica (Mammalia, Artiodactyla)
Authors: Manceau Valérie , Crampe Jean‐Paul , Boursot Pierre , Taberlet Pierre
Published: February 2006

The Pyrenean population of Spanish wild goat (Capra pyrenaica pyrenaica) is nearly extinct. To find the most appropriate source of individuals for supplementing the Pyrenean population, we identified Evolutionary Significant Units (ESUs) among populations of the Capra pyrenaica species. We have examined sequence variability of portions of the mitochondrial DNA (mtDNA) control region and cytochrome b (cyt b) gene. Samples were from seven populations of Spanish wild goat distributed over the species' geographic range. The level of divergence between the Pyrenean and other Spanish haplotypes is almost as high as the divergence between the Alpine (C. ibex ibex) and the Spanish wild goats. In addition, the Pyrenean goat is morphologically distinct from other Spanish wild goats. Therefore the Pyrenean population should be considered as an ESU. For the reinforcement, we suggest either using individuals from the most polymorphic Spanish population, or mixing individuals from diverse Spanish origins, since all the other Spanish populations are equally genetically distant from the Pyrenean population.
Time frames for population viability analysis of species with long generations: an example with Asian elephants
Authors: Armbruster Peter , Fernando Prithiviraj , Lande Russell
Published: February 2006

We extend an earlier population viability analysis (PVA) of the Asian elephant (Elephas maximus) conducted by Sukumar & Santiapillai (1993) in order to examine how conclusions about viability can depend upon the time frame examined. We find that there is an approximately 200 year lag period before extinction events begin to occur in slowly declining populations of E. maximus. Therefore, examining population persistence over a 100 year time frame seriously underestimates the risk of population extinction over a longer, 1000 year period. These results are supported by the use of both a species‐specific model of elephant demography, ELEPHANT, and a generic PVA package, VORTEX.

For populations with long generations, a 100 year time period will often not be sufficient to evaluate demographic processes leading to extinction. These results have important implications for how investigators conduct PVAs, and for the listing of endangered species by the World Conservation Union (IUCN).
The question of scale in threat analysis: a case study with Brazilian mammals
Authors: Grelle Carlos E. de V. , Fonseca G. A. B. , Fonseca M. T. , Costa L. P.
Published: February 2006

Rates of biodiversity loss are clearly associated with a reduction in the extent of original habitat. The most frequently used method to derive such estimates comes from the well‐known species–area relationship. We explored the relationship between habitat loss and area for the Brazilian mammal fauna on a biome level (Atlantic Forest, Cerrado and the Brazilian portion of the Amazon basin), as well as on a smaller regional scale (the Rio Doce Valley of the Atlantic Forest). Habitat loss overestimates the number of threatened species when the entire species pool is considered (endemics and wide‐ranging species). Restricting the analyses to the endemic species, the predicted extinction as a function of habitat loss in the Atlantic Forest and in the Cerrado is found to be greater than the number of taxa actually listed as threatened. This relation is reversed in the Amazon. When considering only the localized species pool for the Rio Doce Valley region of the Atlantic Forest, the function accurately predicts the number of extinctions resulting from habitat loss. We suggest that there is both theoretical and empirical evidence to suggest that threat analysis will generate more accurate estimates of species loss when conducted on a more local scale, particularly for the fauna of non‐insular, continental regions. Furthermore, other phenomena affecting the likelihood of extinction of certain groups of species, such as hunting, need to be taken into account in order to better understand the dynamics of biodiversity loss.
Helping reintroduced houbara bustards avoid predation: effective anti‐predator training and the predictive value of pre‐release behaviour
Authors: Heezik Yolanda van , Seddon Philip J. , Maloney Richard F.
Published: February 2006

The success of captive‐breeding and release programmes is often compromised by predation of released individuals, which are naïve about predators. Pre‐release behavioural preparation of release candidates in the form of anti‐predator training has been attempted infrequently, usually using models of predators, but success was most often measured in terms of improved behavioural responses rather than survival to breeding age after release. Here we report that post‐release survival of captive‐reared houbara bustards (Chlamydotis [undulata] macqueenii) was improved through exposure to a live predator before release: a result with possible applications for a wide range of species currently the focus of reintroduction projects. We also show that rearing houbara with minimal human contact and training with a model of a predator had no effect on post‐release survival. Moreover, neither pre‐release behavioural responses to a model predator nor the degree of tonic immobility were predictors of post‐release survival.
Molecular genetic relationships of the extinct ostrich, Struthio camelus syriacus: consequences for ostrich introductions into Saudi Arabia
Authors: Robinson Terence J. , Matthee Conrad A.
Published: February 2006

We sequenced part of the mitochondrial DNA control region of the extinct Arabian ostrich, Struthio camelus syriacus, to determine its phylogenetic relationship to the surviving subspecies, and to provide genetic information pertinent to the reintroduction of contemporary ostrich into Saudi Arabia. Parsimony, neighbour joining, maximum likelihood and a minimum spanning network all supported a close genetic association between the Arabian S. c. syriacus and the north African S. c. camelus. Furthermore, all our analyses suggest a recent common ancestry for the southern African S. c. australis and the east African S. c. massaicus. The Somali race, S. c. molybdophanes, was phylogenetically the most distinct of the ostrich taxa. Our data are supportive of a management decision to introduce S. c. camelus into areas once occupied by the extinct S. c. syriacus based predominantly on their geographic proximity and phenotypic features. Moreover, the presence of a shared lineage in these taxa indicates that gene flow between the two geographic forms may have been possible in the recent evolutionary past, probably along the Egyptian–Sinai–Israel passageway.
Range collapse of a tropical cervid (Cervus eldi) and the extent of remaining habitat in central Myanmar
Authors: McShea William J. , Leimgruber Peter , Aung Myint , Monfort Steven L. , Wemmer Christen
Published: February 2006

The thamin (Cervus eldi) is an endangered species of deer whose present range is greatly reduced from its original distribution covering the deciduous forests throughout south‐east Asia. We mapped the present distribution of thamin using ground surveys and tied this information to habitat types derived from satellite images in order to detect patterns that might indicate the landscape features which precipitated the decline. We conducted a survey of 24 out of 28 Myanmar townships that were reported to contain thamin in 1992, and evidence of thamin were found in 23 of these townships, predominately in mixed deciduous forests where dipterocarp trees were present. There was no significant correlation between the number of thamin detected and forest remaining in the township, or the size of the human or livestock population. A landcover classification of Landsat Thematic Mapper images indicated 58% of the study area contained deciduous forest, of which 12% was dipterocarp forest. Forest tracts containing thamin were digitized and landscape analyses were conducted on a resampled habitat map that emphasized dry and dipterocarp deciduous forest. Of six landscape variables measured only core area size was a significant predictor for the presence of thamin. None of the unsurveyed indaing forest tracts possessed a core area large enough to support thamin. The pattern of thamin decline matches predictions that peripheral, rather than central, populations are more likely to persist in declining species.
Managing disease threats to wild mammals
Authors: Woodroffe Rosie
Published: February 2006

Infectious disease is an emerging threat that conservationists are ill‐equipped to manage. The threat is greatest for small populations, which can be driven to extinction by virulent pathogens; these are usually generalist pathogens that ‘spill over’ from other host species, often domestic animals. Recent attempts at disease control have taken a variety of forms, some directed at threatened hosts themselves, and others involving reservoir hosts. Thus far, few such attempts have demonstrated clear benefits of intervention, often because they were ‘crisis management’ tactics allowing no comparison with untreated controls. Design of future strategies is hampered by a lack of basic information concerning the pathogens that represent serious threats, their epidemiology in multiple‐host systems, and the vaccination or treatment protocols likely to be most effective under field conditions. In general, vaccination and treatment will be most valuable in tiny populations facing very high extinction risks. However, interventions that are poorly planned or under‐funded have the potential to do more harm than good. In larger populations, or over larger areas, intensive management may be inappropriate, unsustainable, or simply impractical. In these circumstances, managing population size, structure or contact between host species could offer promising alternatives to intervention.
The plateau pika (Ochotona curzoniae) is a keystone species for biodiversity on the Tibetan plateau
Authors: Smith Andrew T. , Foggin J. Marc
Published: February 2006

It is necessary to look at the big picture when managing biological resources on the Qinghai—Xizang (Tibetan) plateau. Plateau pikas (Ochotona curzoniae) are poisoned widely across the plateau. Putative reasons for these control measures are that pika populations may reach high densities and correspondingly reduce forage for domestic livestock (yak, sheep, horses), and because they may be responsible for habitat degradation. In contrast, we highlight the important role the plateau pika plays as a keystone species in the Tibetan plateau ecosystem. The plateau pika is a keystone species because it: (i) makes burrows that are the primary homes to a wide variety of small birds and lizards; (ii) creates microhabitat disturbance that results in an increase in plant species richness; (iii) serves as the principal prey for nearly all of the plateau's predator species; (iv) contributes positively to ecosystem‐level dynamics. The plateau pika should be managed in concert with other uses of the land to ensure preservation of China's native biodiversity, as well as long‐term sustainable use of the pastureland by domestic livestock.
Infectious disease and the conservation of free‐ranging large carnivores
Authors: Murray Dennis L. , Kapke Cynthia A. , Evermann James F. , Fuller Todd K.
Published: February 2006

Large carnivores are of vital importance to the stability and integrity of most ecosystems, but recent declines in free‐ranging populations have highlighted the potentially devastating effect of infectious diseases on their conservation. We reviewed the literature on infectious diseases of 34 large (maximum body mass of adults >20 kg) terrestrial carnivore species, 18 of which are considered to be threatened in the wild, and examined reports of antibody prevalence (seroprevalence) and cases of infection, mortality and population decline. Of 52 diseases examined, 44% were viral, 31% bacterial and the remainder were protozoal or fungal. Many infections were endemic in carnivores and/or infected multiple taxonomic families, with the majority probably occurring via inhalation or ingestion. Most disease studies consisted of serological surveys for disease antibodies, and antibody detection tended to be widespread implying that exposure to micro‐organisms was common. Seroprevalence was higher in tropical than temperate areas, and marginally higher for infections known to occur in multiple carnivore groups. Confirmation of active infection via micro‐organism recovery was less common for ursids than other taxonomic groups. Published descriptions of disease‐induced population decline or extinction were rare, and most outbreaks were allegedly the result of direct transmission of rabies or canine distemper virus (CDV) from abundant carnivore species to less‐common large carnivores. We conclude that the threat of disease epidemics in large carnivores may be serious if otherwise lethal infections are endemic in reservoir hosts and transmitted horizontally among taxa. To prevent or mitigate future population declines, research efforts should be aimed at identifying both the diseases of potential importance to large carnivores and the ecological conditions associated with their spread and severity.
Use of genetic data for conservation management: the case of the Arabian oryx
Authors: Marshall T. C. , Sunnucks P. , Spalton J. A. , Greth A. , Pemberton J. M.
Published: February 2006

In this study we investigate some applications of genetic markers in animal conservation, using the Arabian oryx (Oryx leucoryx) as an example. Out of 66 sets of microsatellite primers from other ruminants, 58% were found to amplify microsatellites in Arabian oryx. Polymorphism (50% of loci amplified) and allelic diversity (mean 2.1 alleles/locus amplified) were within the range found in other ruminants. Arabian oryx (n= 343) representing most of the major groups world‐wide were typed at six loci. Low but significant population differentiation was found between most oryx groups, suggesting that management of Arabian oryx has led to substantial genetic mixing between populations. Forty percent of the alleles in one additional Arabian oryx sample from the pre‐extinction population in Oman were not found in any contemporary Arabian oryx, and two out of four contemporary populations were deficient in rare alleles, suggesting that the species has lost some neutral genetic variation. The microsatellite loci were sufficiently polymorphic for identification of an Arabian oryx sample in a forensic context, but were not sufficiently polymorphic for large‐scale parentage inference. We suggest that it is important to evaluate whether genetic markers are likely to have sufficient power to answer particular conservation questions prior to committing conservation resources to genetic typing.
Human exploitation of male fiddler crab claws: behavioural consequences and implications for conservation
Authors: Oliveira Rui F. , Machado José L. , Jordão Joana M. , Burford Fiona L. , Latruffe Claire , Mcgregor Peter K.
Published: February 2006

Male fiddler crabs have one of their feeding claws greatly enlarged, which may comprise up to 40% of their weight. In southern Portugal (Ria Formosa) the major claw of the fiddler crab Uca tangeri is a local delicacy. Fishermen break off the male major claw and throw the crab back into the mudflat to regenerate a new one. Approximately 38 % of the males sampled had a missing or a regenerating claw. Although individuals are not removed from the population the operational sex ratio is biased towards females since other males and females behave towards clawless males as if they were females. Moreover, removing the major claw from males prevents them from signalling (waving display) to females to attract them to their breeding burrows and it also places them at a disadvantage if they have to defend their burrows from males with intact claws. Thus, the harvesting of male fiddler crab claws has potential consequences at the population level. In this paper we investigated these potential consequences by comparing an exploited population of fiddler crabs at Ria Formosa with a remote population at the Mira estuary that is not under human exploitation. The unexploited population has significantly larger males and a significantly higher density of burrows. The operational sex ratio is also significantly different between the two populations with a female‐biased sex ratio in the exploited population. These preliminary results suggest that claw harvesting in fiddler crabs has a measurable effect at the population level. The consequences of this type of fishery in which the individuals are not removed from the population but the population structure is potentially affected need further investigation.
Housing developments in rural New England: effects on forest birds
Authors: Kluza Daniel A. , Griffin Curtice R. , Degraaf Richard M.
Published: February 2006

In rural New England, forest fragmentation is caused by housing developments in forested areas. To evaluate the effects of these changes on forest birds, we compared bird assemblages between forests with different housing densities in western Massachusetts. Species occurrences and relative abundances were determined from systematic point count surveys and mist‐netting at three plots in forest of low housing density (0–0.05 houses/ha) and of moderate housing density (0.60–6.70 houses/ha) in 1993 and 1994. Among guilds, Neotropical migrants and forest‐interior species had significantly lower abundances in forests of moderate housing density. Abundances of ground/shrub nesting birds as a group, and of individual species such as veery (Catharus fuscescens), ovenbird (Seiurus aurocapillus) and wood thrush (Hylocichla mustelina), were greater in forest of low housing density, but blue jays (Cyanocitta cristata) were more abundant in forest of moderate housing density. Although the abundances of ground/shrub nesting birds were positively related to ground cover, this vegetation structure did not differ between forest types. Avian and mammalian nest predators may be responsible for the trends in bird abundance. Avian nest predators may recognize forest of moderate housing density as edge habitat, and this rural development may also support relatively high densities of mammalian nest predators. These trends suggest that birds of New England's relatively extensive forests may be subject to greater fragmentation effects than generally thought, as a result of increasing rural housing development within forests.
Winter habitat and distribution of the endangered golden‐cheeked warbler (Dendroica chrysoparia)
Authors: Rappole John H. , King David I. , Leimgruber Peter
Published: February 2006

The golden‐cheeked warbler (Dendroica chrysoparia) is an endangered Neotropical migrant that breeds in oak (Quercus)/juniper (Juniperus) habitat of the Edwards Plateau in central Texas. Recently work has been done on the factors affecting breeding populations of this species, but little is known about winter habitat use or distribution. We used extensive field surveys in Honduras and Guatemala to obtain locational information, which was used with topographical and remote sensing data, to identify and calculate the amount of suitable habitat available, and to map the species' distribution in the region. Most individuals were found in pine–oak from 1100–2400 m (
image
= 1651 (± 246) m) in elevation, a habitat type that occupied 29.8% of the total land area above 914 m in the region investigated. Based on this information and existing locational data from the literature, we present a map of the winter range for the golden‐cheeked warbler. Threats to the species during this period of the life cycle include logging, burning and clearing for pasture and agriculture.
The mock turtle syndrome: genetic identification of turtle meat purchased in the south‐eastern United States of America
Authors: Roman Joseph , Bowen Brian W.
Published: February 2006

Much of the demand for turtle meat in North America and Europe during the past four centuries has been met using green turtle (Chelonia mydas) and other marine turtles. As stocks of marine turtles dwindled, harvest of the alligator snapping turtle (Macroclemys temminckii), the largest freshwater turtle in North America, increased in the south‐eastern USA. As a result, this species has declined and is now protected in every state of the USA except Louisiana. There is concern that the remaining legal trade in turtle products may serve as a cover for illegally harvested species. To assess the composition of species in commerce, we purchased 36 putative turtle meat products in Louisiana and Florida. Using cytochrome b and control region sequences of the mitochondrial genome, we identified 19 samples as common snapping turtle (Chelydra serpentina), three as Florida softshell (Apalone ferox), one provisionally as softshell turtle (Apalone sp.), one as alligator snapping turtle, and eight as American alligator (Alligator mississippiensis). It appears that M. temminckii is no longer the predominant species in markets of Louisiana. The presence of alligator meat in a quarter of the samples indicates that the trade in turtle products is not entirely legitimate. As is often the case for unsustainable wildlife harvests, large, esteemed species, such as green turtle and alligator snapper, have been replaced by smaller, more‐abundant or mislabelled species, a phenomenon we refer to as the mock turtle syndrome.
The threatened status of restricted‐range coral reef fish species
Authors: Hawkins Julie P. , Roberts Callum M. , Clark Victoria
Published: February 2006

Coral reefs are the most diverse ecosystem in the sea. Throughout the world they are being over‐fished, polluted and destroyed, placing biodiversity at risk. To date, much of the concern over biodiversity loss has centred on local losses and the possibility of global extinction has largely been discounted. However, recent research has shown that 24% of reef fish species have restricted ranges (< 800 000 km2), with 9% highly restricted (< 50 000 km2). Restricted‐range species are thought to face a greater risk of extinction than more widespread species since local impacts could cause global loss. We searched for information on status in the wild and characteristics of 397 restricted‐range reef fish species. Fish body size, habitat requirements and usefulness to people were compared with those of a taxonomically‐matched sample of more widespread species. We found that on average species with restricted ranges were significantly smaller (mean total length 19.1 cm versus 24.4 cm), tended to have narrower habitat requirements and were less used by people. Greater habitat specificity will tend to increase extinction risk while, if real, more limited usefulness (equivalent to exploitation) may reduce risk. Fifty‐eight percent of restricted‐range species were considered common/abundant in the wild and 42% uncommon/rare. Population status and threats to 319 species for which data were available were assessed according to the categories and criteria of the IUCN red list of threatened animals. A number of species were found to be rare, were exploited and had highly restricted ranges overlapping areas where reef degradation is particularly severe, placing them at a high risk of extinction. Five species were listed as Critically Endangered, two of them possibly already extinct in the wild, one as Endangered and 172 as Vulnerable. A further 126 species fell into Lower Risk categories and 11 were considered Data Deficient. Given the intensity of impacts to reefs, the broad geographical areas affected and the large numbers of restricted‐range species, global extinctions seem likely. Urgent management action is now crucial for the survival of several species of reef fishes.
Grey squirrels have high seroprevalence to a parapoxvirus associated with deaths in red squirrels
Authors: Sainsbury Anthony W. , Nettleton Peter , Gilray Janice , Gurnell John
Published: February 2006

The population of red squirrels (Sciurus vulgaris) in the British Isles is in decline and is being supplanted by the grey squirrel (Sciurus carolinensis). It has been suggested that parapoxvirus‐associated disease has caused significant mortality in red squirrels and that grey squirrels are the source of the virus. A direct enzyme‐linked immunosorbent assay (ELISA) was developed for the measurement of antibody to squirrel parapoxvirus. We tested 140 sera from red squirrels and 223 from grey squirrels from different populations in the UK. A high percentage (61%) of apparently healthy grey squirrels, were found to have been exposed to the parapoxvirus. Only 2.86% (4/140) of red squirrels had antibody and three of these animals had parapoxvirus‐associated disease. We postulate that the grey squirrel may act as a reservoir host for the virus.
Simultaneous inbreeding and outbreeding depression in reintroduced Arabian oryx
Authors: Marshall T. C. , Spalton J. A.
Published: February 2006

In most species the offspring of closely related parents have reduced fitness compared with the offspring of unrelated parents, a phenomenon known as inbreeding depression. However if parents are very distantly related, their offspring may also have reduced fitness. This pattern, outbreeding depression, has been most commonly observed in plants and only rarely in animals. Here we examine the consequences of inbreeding and outbreeding on juvenile survival of reintroduced Arabian oryx (Oryx leucoryx) in Oman, a population with a small number of founders drawn from a number of sources. Using microsatellite‐based measures of inbreeding and outbreeding, there was no apparent relationship between inbreeding or outbreeding and survival when inbreeding and outbreeding were tested in separate statistical models. However when inbreeding and outbreeding were tested in the same statistical model, we found simultaneous inbreeding depression and outbreeding depression acting on juvenile survival. Outbreeding depression may be more common in vertebrates than previously supposed, and conservation strategies that seek to maximize the genetic diversity of managed populations may risk mixing lineages that are sufficiently differentiated to cause outbreeding depression among descendants.
Flagship species, ecological complementarity and conserving the diversity of mammals and birds in sub‐Saharan Africa
Authors: Williams Paul H. , Burgess Neil D. , Rahbek Carsten
Published: February 2006

More biodiversity could be protected in situ if the few species that attract the most popular support (the ‘flagship’ species) had distributions that also covered the broader diversity of organisms. We studied how well different groups of mammals performed for representing the diversity of mammals and breeding birds among 1° areas of sub‐Saharan Africa. We demonstrate that choosing areas of sub‐Saharan Africa using either conservationists' six primary flagship mammals, or the six ‘Big Five’ mammals popular with wildlife tourists, is not significantly better for representing the diversity of mammals and birds than choosing areas at random. Furthermore, neither of these groups is significantly better for representing the diversity of mammals and birds than groups of the same number of species chosen at random. We show that in order to succeed in representing many mammals and birds in area selection, it is not sufficient for the groups used for selection to occur in many different eco‐regions, they must also have low overlaps in distribution, so as to provide high ecological complementarity (a similar pattern of ecological complementarity must be shared by the larger group of species to be represented). Therefore there may be a need for an explicit policy to balance the requirements of flagship conservation and broader biodiversity conservation, which will have implications for the distribution of resources.
Is one migrant per generation sufficient for the genetic management of fluctuating populations?
Authors: Vucetich John A. , Waite Thomas A.
Published: February 2006

Small isolated populations may face an increasing risk of extinction due to the loss of genetic diversity. This increasing risk, though, may be offset by gene flow, provided the population receives an adequate number of migrants per generation. We show that as temporal fluctuation in population size (FPS) increases, so too does the required number of immigrants. This increase in the requisite number of immigrants arises because the ratio of census size to effective population size decreases with increasing FPS. Because all populations fluctuate, our work extends a recent challenge to the widely adopted one migrant per generation rule, which refers to the supposedly requisite number of immigrants. In a sample of 44 animal populations, ˜60% of the populations fluctuated enough to require >10 immigrants per generation to avoid a substantial loss of genetic diversity, and ˜25% fluctuated enough to require >20 immigrants per generation. We thus recommend that estimation of the requisite number of immigrants take into account fluctuation in population size.
Dynamics of reintroduction in an indigenous large ungulate: the wood bison of northern Canada
Authors: Larter N. C. , Sinclair A. R. E. , Ellsworth T. , Nishi J. , Gates C. C.
Published: February 2006

We document the recolonization of an indigenous large herbivore into its historic range. Eighteen wood bison (Bison bison athabascae) were reintroduced into the Mackenzie Bison Sanctuary of the Northwest Territories, Canada, in 1963. The population subsequently increased in number and range, peaking at about 2400 in 1989; numbers were estimated at about 1900 in 1998. Recolonization occurred through a series of increases in local areas followed by pulses of dispersal and range expansion. This pattern was originally described for exotic species' introductions. Differences in diet and overwinter survival of calves over the bison's range suggest that intraspecific competition for food provided the stimulus for range expansion. For a conservation strategy, the reintroduction of animals into several independent sites in their historic range would facilitate recolonization and achieve a faster spread than a reintroduction into one site followed by waiting for the population to spread as a result of its own density dependent responses.
Mitochondrial DNA and palaeontological evidence for the origins of endangered European mink, Mustela lutreola
Authors: Davison Angus , Griffiths Huw I. , Brookes Rachael C. , Maran Tiit , Macdonald David W. , Sidorovich Vadim E. , Kitchener Andrew C. , Irizar Iñaki , Villate Idoia , González‐esteban Jorge , Ceña Juan Carlos , Ceña Alfonso , Moya Ivan , Miñano Santiago Palazón
Published: February 2006

The European mink Mustela lutreola is one of Europe's most endangered carnivores, with few vulnerable populations remaining. Surprisingly, a recent phylogeny placed a single mink specimen within the polecat (M. putorius, M. eversmannii) group, suggesting a recent speciation and/or the effects of hybridization. The analysis has now been extended to a further 51 mink and polecats. As before, phylogenetic methods failed to resolve the relationships between the species. One haplotype (C11) was found in both species, and predominated in European mink from Spain and eastern Europe. The known M. lutreola fossils are of very young date, so either mink arose recently, or else the situation is confused by hybridization and a biased fossil recovery. The study highlights the dangers of using a single genetic marker in defining Evolutionarily Significant Units (ESUs). Polecats and European mink are clearly distinct in their morphology and ecology, and should still be considered as separate ESUs, but without further data it is difficult to define Management Units. Following the precautionary principle, we recommend that for the moment European mink in eastern Europe (Belarus, Estonia and Russia) and Spain should be managed separately.
Does equalization of family sizes reduce genetic adaptation to captivity?
Authors: Frankham Richard , Manning Heidi , Margan Sienna H , Briscoe David A.
Published: February 2006

Genetic adaptation to captive environments is likely to reduce the reproductive fitness of endangered species when they are reintroduced into natural environments. Equalization of family sizes is predicted to halve genetic adaptation to captivity as it removes selection among families and is recommended in captive management of threatened species. This prediction was evaluated by comparing the reproductive fitnesses of replicate populations of Drosophila maintained using either equal (EFS) or variable family sizes (VFS) for 25 generations in captivity under uncrowded conditions on a medium containing CuSO4. After 25 generations, EFS populations produced 8.8% more offspring per pair than their outbred base population on CuSO4 medium, while VFS produced 17.5% more. Consequently, the rate of genetic adaptation to captivity in EFS was about half that in VFS, as predicted. In simulated ‘wild’ conditions (crowded, competitive conditions on medium lacking CuSO4), both treatments showed much lower reproductive fitness than their outbred base population, the reductions being 38% in EFS populations and 43% in VFS populations. Surprisingly, reproductive fitness of the two treatments did not differ significantly under these conditions. These results raise doubts about the ability of equalization of family sizes to reduce genetic deterioration that adversely affects reintroduction success for captive populations of endangered species.
Comparative analyses of correlates ofRed data bookstatus: a case study using European hoverflies (Diptera: Syrphidae)
Authors: Sullivan Matthew S. , Gilbert Francis , Rotheray Graham , Croasdale Stevan , Jones Martin
Published: February 2006

We present a comparative analysis of correlates ofRed data bookstatus that controls for phylogeny. As a model system we use 244 species of hoverfly (Diptera: Syrphidae) from the British fauna, with theirRed data bookstatuses in Britain and three regions of Germany. The analysis is confined to four adult characters, withRed data bookstatus as the dependent variable. Associated with an increase in risk of extinction were a decrease in flight period and an increase in wing length (in two regions). Variables representing the number of habitats occupied and whether species were single‐ or multi‐brooded were not associated with an increase in risk of extinction. At this stage we restrict our analysis to the identification of patterns rather than speculation as to causal mechanisms, but the patterns themselves are of value to conservation biologists, provided the methods used to identify them control for the possible confounding effects of phylogeny.