We designed an individual-based model to explore the effects of unusual life-history parameters and changing ecological conditions on the population dynamics and persistence of the monogamous Hypogeomys antimena, a Malagasy rodent with a recently dramatic decline in its geographical range. Model parameters were derived from extensive field studies carried out since 1992. The simulations predict that Hypogeomys is quite sensitive to small fluctuations in reproductive rate, offspring and adult mortality. Minimum habitat requirements of a viable population that is able to cope for the next 100 years with fluctuating ecological conditions were reached in forest areas of about 3000 ha. However, this habitat size will not represent a stable population. Under current conditions, the population size will continuously decline almost independently of the modelled forest block size. A stable population demography can only be reached by slightly improving the life-history conditions. The survival prospect of the largest at least partly protected forest fragment currently inhabited by H. antimena are discussed.

Genetic variation at the major histocompatibility (MHC) class I loci was examined in captive and wild samples of three subspecies of tiger (Bengal, Panthera tigris tigris; Siberian, P. t. altaica; Sumatran, P. t. sumatrae) by Southern blot analysis using the domestic cat probe FLA 24. All captive populations showed at least moderate variability compared to other felids. Captive tigers were, on average, significantly more variable than wild tigers, but this was not consistent among subspecies. Significant geographic genetic population structure was found at the MHC class I loci among both captive and wild tigers. Phylogenetic analysis of both captive and wild tigers placed Sumatran tigers basally. In a combined phylogenetic analysis, captive and wild tigers of the same subspecies occurred near one another, indicating that the structure of the captive populations reflects that of the wild populations.

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.

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 (× = 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.

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.

This study reports the population responses of the lizard Psammodromus algirus to forest fragmentation by comparing its distribution in two contrasting situations of habitat conservation: a well connected mosaic landscape (forest patches larger than 2000 ha and/or connected by corridors that prevent their isolation), and an archipelago of forest remnants embedded within a matrix of cereal fields. The frequency of occurrence of P. algirus was larger in the unfragmented habitats (14 out of 19 censused plots) than in the fragments (two out of of 21 wood-lots). Vegetation structure was a good predictor of lizard occurrence under conditions of no fragmentation, but not in the fragments, where high plant cover seemed a necessary, but insufficient, condition for the survival of lizard populations, and where remnant size was the only variable that differed significantly between wood-lots with and without lizards. Historical fragmentation of the habitat is also crucial for understanding the current distribution of lizards, as shown by their absence from a large forest that was highly fragmented in the past but which has been regenerating for decades. It is hypothesized that the combined effects of fragmentation and predation in small remnants have led to the extinction of P. algirus in fragments smaller than c. 90 ha, recolonization being prevented by the very limited dispersal abilities of these forest lizards.

Five out of 169 fertile California condor (Gymnogyps californianus) eggs laid in captivity have exhibited chondrodystrophy, a lethal form of dwarfism. Pedigree records indicate that this chondrodystrophy, like similar conditions in chickens, turkeys and quail, is probably inherited as an autosomal, recessive allele. We estimate that the frequency of this putative allele is about 9%. This high frequency is probably due to a founder effect. We consider three management options for the allele: ignoring it, eliminating it by selection and minimizing its phenotypic manifestation by avoiding matings between possible carriers. We recommend minimizing its phenotypic expression because an unacceptably large proportion of condors (up to 78 out of 146) would be prevented from breeding under a selection strategy designed to eliminate the allele. We predict that many captive populations will prove similar to the California condor population in that it will prove inadvisable or impractical to select against one or more deleterious alleles detected in the population.

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.

There are many methods available for evaluating conservation priorities. Traditional methods of species richness, genus richness and critical species counts were compared with newer methods of phylogenetic and genetic diversity. Conservation priorities for areas designated by the Interim biogeographic regionalisation for Australia (Thackway & Cresswell, 1995) were assessed on the basis of the freshwater crayfish fauna of Australia. Distributions for all crayfish species were taken from the literature, and plotted in the IBRA areas. Species and genus richness, as well as the number of rare or endangered species were calculated for each area. A phylogeny of 35 representative crayfish based on 16 S rDNA sequence data was used to assess phylogenetic and genetic diversity of species and genera. Methods of species richness and phylogenetic diversity agreed to a large extent in their ranking of areas, both methods agreed that the north-west coast of Tasmania and the south-eastern portion of the continent were of highest priority for conserving the greatest amount of diversity. These results differ greatly from high priority areas based on other taxonomic groups, emphasizing the importance of broad taxonomic and ecological sampling in making conservation decisions.

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.

Anthropogenic natural habitat transformation presents the single most important threat to global biodiversity. Land cover data, based on Landsat Thematic Mapper (TM) imagery, were used to derive land use information for the Gauteng, Mpumalanga and Northern provinces of South Africa. The assessment integrated land use data with species presence data (15 × 15 minute grid cell resolution) for butterflies, mammals, birds and endemic vascular plants. The objectives of the present study were: (1) to identify areas at a regional scale where there is a possible conflict between biodiversity conservation interests and current land uses; (2) to investigate the influence of incorporating a land use constraint (LUC) into a conservation area selection algorithm, while taking cognizance of the existing reserve system; (3) to investigate the circumstances of species recorded within these conflict areas. Many grid cells identified as species richness hotspots, rarity hotspots or as part of the complementary network selected by the unconstrained algorithm were in reality largely transformed or modified. These areas should thus be avoided when striving to identify a viable conservation network. Although the LUC algorithm selected more grid cells to represent all species, it succeeded in increasing the percentage of natural vegetation within the selected conservation network and highlighted areas where potential conflicts should be thoroughly investigated at a local scale.

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.

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.

The current extinction crisis is caused primarily by human impacts upon wild populations. Large carnivores are especially sensitive to human activity; because their requirements often conflict with those of local people, predators have been actively persecuted in most regions of the world. In this paper, the impact of people upon predators is analysed by relating local carnivore extinctions to past and projected human population densities. There are strong associations between high human density and the loss of carnivore populations from a region. Interspecific variation in ability to survive at high human densities probably reflects species' ability to adapt to human-modified habitats. However, regional and temporal variation in individual species' sensitivity to human density is more likely to reflect the activities of local people than the phenotypes of local carnivores. Local culture, government policy and international trade all influence human attitudes to predators and, therefore, the impact of people upon carnivore populations. The importance of these factors may mean that extinction risks for carnivores will continue to increase, even though human population growth is projected to deccelerate during the new millennium. This points to an urgent need for techniques to resolve conflicts between people and predators at either the local or landscape level.

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.

Habitat selection by translocated black howler monkeys (Alouatta pigra) was studied in Belize, Central America. Ranging patterns of two recently translocated groups were contrasted with those of two groups in the same area with established home ranges, on a yearly and monthly basis. All groups concentrated their activities along stream beds at elevations below 200 m. Newly translocated groups increased the percentage of their monthly ranges in riverine areas (within 100 m of a water source) over the year of the study (with the exception of the last month) while established groups did not. Areas used more than five times by the monkeys contained larger trees and a greater relative coverage of major food species than low-use areas even though they had a lower overall species richness and diversity. These monkeys may be selecting habitat within the forest based upon vegetative differences and ranging patterns may be affected by patterns of food availability.

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.