The red-crested pochard (Netta rufina), a Eurasian diving duck, has seen its numbers declining and has received strong conservation concern. Data on population size and rate of decline are required to establish management plans, none of which is available for this species. Here we present the first population size estimate taking into account detection probability and habitat use in the Camargue, southern France. A non-random sample of 33 lakes was used to estimate detection probability from point-counts. Detectability was low, with only 57.5% of individual broods detected. A random sample of 37 lakes was then used to estimate brood densities. Adjusted densities (taking into account detection probability) were 0.1106 broods per ha of reedbed. Adjusted densities were extrapolated to the entire surface area of reedbeds in the Camargue estimated from a GIS to obtain abundance estimates of the brood population. A minimum estimate of 559 breeding pairs was obtained (95% confidence interval: 436-855). This estimate is much higher than previous ones (80-100 pairs for the Camargue, 250 pairs for France), and indicates strong underestimation of the population size when not taking into account detectability. Our results suggest that the red-crested pochard may require a reassessment of its conservation status for France and Europe. They further suggest that taking detection probability into account in population estimates of other cryptic species, and notably those of conservation concern, may help clarify their conservation status and may even affect the setting of conservation priorities.

We propose an original approach to model the effect of the initial spatial distribution of a reintroduced metapopulation (one-patch release versus multi-patch release) on local adaptation. Genetic and demographic processes are considered to investigate how the different patterns of adaptation resulting from initial conditions affect metapopulation viability. In agreement with classical interpretations in the fields of population biology and evolutionary genetics, we observe an influence of the degree of environmental correlation among patches on demographic processes and an influence of inter-patch connection on genetic processes. However, our results uncover some further effects of the environment, owing to positive feedback interactions among demographic and genetic processes. When considering the one-patch release, demographic stochasticity engenders a delay in the colonization of initially empty patches. This delay enhances the genetic asymmetry among patches (in terms of local adaptation), which in turn increases demographic asymmetry. In contrast, the multi-patch release produces similar levels of adaptation among patches. Metapopulation dynamics is strongly influenced by these differences, with contrasting effects under different environments. The pattern of adaptation produced by the one-patch release strategy is optimal under a regime of recurrent slight perturbations or environmental stochasticity, while the multi-release strategy is optimal in the presence of rare and severe perturbations.

Hispaniola has been identified as a global priority for avian conservation. However, little quantitative information has been available to help guide optimal strategies for conservation action on the island. Here, the first broad-scale look has been assembled of the distribution of species of conservation concern among protected areas in Haiti and the Dominican Republic and their occurrences have been analysed to determine where conservation activities might be focused to serve avian conservation interests. An iterative, heuristic complementarity approach was used, such that the most highly ranked reserve is that which protects the greatest number of species of conservation concern and subsequently ranked reserves are those that add the most species of conservation concern that are not included in the first reserve. Parks are prioritised by the presence/absence of species of concern and prioritised a second time with individual species first being weighted by species-specific extinction risks and then by uniqueness in terms of endemism at the island or regional level. Parks of highest importance are the Sierra de Bahoruco National Park and Jaragua National Park, but the importance of other protected areas to avian conservation is also documented and discussed.

Protecting systematically selected areas of land is a major step towards biodiversity conservation worldwide. Indeed, the identification and designation of protected areas more often than not forms a core component of both national and international conservation policies. In this paper we provide an overview of those Special Protection Areas and Ramsar Sites that have been classified in Great Britain as of 1998/99 for a selection of wintering waterbird species, using bird count data from the Wetland Bird Survey. The performance of this network of sites is remarkable, particularly in comparison with published analyses of networks elsewhere in the world. Nevertheless, the current site-based approach, whilst having the great benefit of simplicity, is deliberately biased towards aggregating species at the expense of the more dispersed distribution species. To ensure that the network continues successfully to protect nationally and internationally important waterbird populations, efforts now need to concentrate on the derivation of species-specific representation targets and, in particular, the ways in which these can be incorporated into the site selection process. Although these analyses concern the performance of protected areas for waterbirds in Great Britain, the results have wide-ranging importance for conservation planning in general and the design of protected area networks.

Grouse, 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.

The Shenandoah salamander (Plethodon shenandoah) is restricted to three isolated talus outcrops in Shenandoah National Park, VA, USA and has one of the smallest ranges of any tetrapod vertebrate. This species was listed as endangered under the US Endangered Species Act in 1989 over concern that direct competition with the red-backed salamander (Plethodon cinereus), successional habitat changes, and human impacts may cause its decline and possible extinction. We address two issues herein: (1) whether extensive introgression (through long-term hybridization) is present between the two species and threatens the survival of P. shenandoah, and (2) the level of population structure within P. shenandoah. We provide evidence from mtDNA haplotypes that shows no genetic differentiation among the three isolates of P. shenandoah, suggesting that their fragmentation is a geologically recent event, and/or that the isolates are still connected by occasional gene flow. There is also no evidence for extensive introgression of alleles in either direction between P. cinereus and P. shenandoah, which suggests that P. shenandoah may not be in danger of being genetically swamped out through hybridization with P. cinereus.

Knowledge of the causes of success or failure in introductions may provide information to help improve the chances that re-introductions succeed. However, the utility of this information will be influenced by the comparability of sets of introduced and re-introduced species. Here, we assess the extent of this similarity using recent historical data on introduced and re-introduced birds. Introductions are less often threatened than expected and have larger ranges and earlier ages at maturity than re-introductions. Introductions also generally have ‘weedy’ life-history characteristics relative to family-typical values, whereas those of re-introductions more closely conform to these typical values. However, introductions and re-introductions do not differ in migratory behaviour, mating system or dichromatism, nor do they show statistically consistent differences in body mass, incubation time or annual fecundity. The taxonomic composition of the lists of introductions and re-introductions is similar, with more species than expected on both lists. Overall, these results suggest that the characteristics of introductions and re-introductions are sufficiently similar that conclusions from studies of the former may reasonably be used to inform studies of the latter.

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

Until 1972, Uganda's national parks boasted of large numbers of large mammal species. Following the breakdown of law and order between 1972 and 1985, large-scale poaching led to an unprecedented decline in numbers of most large mammals in Uganda's national parks. However, the extent of decline varied in the different parks across different animal species. We have investigated the genetic effects of these reductions in four mammalian species (the common warthog, African savannah elephant, savannah buffalo and common river hippopotamus) from the three major parks of Uganda using both microsatellite loci (for elephant and warthog populations) and mitochondrial control sequence variation in the warthogs, elephants, buffaloes and hippopotamuses. Queen Elizabeth National Park showed extreme reduction in nucleotide diversity for two species, the common warthog (π = 0.0%) and African elephant (π = 0.4%); no such decrease was found for the two other species, the buffalo (π = 3.7-5.4%) and hippopotamus (π = 1.7-1.9%), in the three parks. Nuclear microsatellite markers on the other hand showed high gene diversity in all populations in the common warthog (mean He 0.66-0.78) and the African savannah elephant (mean He 0.68-0.72). We interpret these results in terms of varying poaching pressure in the different parks, susceptibility of different species to poaching and differences in effective population sizes at the mitochondrial and nuclear loci.

Cyclura lewisi is an endangered rock iguana endemic to the island of Grand Cayman. Like many other animals, C. lewisi increasingly depends on modified landscapes for its survival. The remaining natural population is too small and fragmented to yield information on the natural history and population biology of this species. Therefore, we studied habitat use in a population of captive-bred, released iguanas in a botanic park. Compositional analysis was used to examine habitat selection and use by iguanas at two scales: selection of home range within the landscape and selection of locations within home ranges. At both scales and for all time periods examined, iguanas preferred modified habitat to natural habitat. Subhabitats were examined only at the scale of selection within the landscape, for which iguanas showed preference in some but not all time periods. Iguanas used artificial retreats more often than natural retreats and commonly occupied retreats in modified areas. Many female iguanas nested in artificial sites within the park. The use of modified habitats and artificial retreats and nests by reintroduced C. lewisi is encouraging, because this and other species of Cyclura may depend on these resources for future survival.

In 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 that M. eugenii maintains high reproductive synchrony while M. parma remains asynchronous. Both species show sexual dimorphism and differences in habitat use as seen in Australia. In addition M. parma is more solitary, and is frequently found in closed-canopy woodland, while M. eugenii tends 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 with M. parma, a species whose persistence in Australia is threatened by fox predation. Finally, we use data on mitochondrial cytochrome b sequence divergence amongst several Macropus taxa to demonstrate close agreement with degree of reproductive isolation.

There is considerable interest in the use of assisted breeding techniques as a component of conservation programmes for a variety of macropods threatened with extinction. While cross-fostering is being conducted in some programmes in captivity, little is known about the best techniques for carrying this procedure out from wild populations. In this study we compare the success of various procedures for isolating small tammar wallaby (Macropus eugenii) and brush-tailed rock wallaby (Petrogale penicillata) pouch young (0.4 g–410 g) for short periods (6 hours) as a first step towards establishing a methodology for recruiting endangered macropod pouch young directly from the wild for foster-rearing in captivity. Pouch temperature and humidity were determined. Pouch young from females in experimental groups were weighed, measured and then isolated, at 30°C, 27°C or 23°C, and 100% humidity. After isolation the weight of pouch young maintained at 30°C and 27°C had declined significantly (2–17% of body weight), whereas those held at 23°C and 100% humidity lost less than 0.5% of body weight. All young were reattached to the active teat of their mother following pouch isolation and their survival and growth monitored. Pouch young from the control group and those isolated at 23°C and 100% humidity survived and grew at normal rates. Only the largest pouch young maintained in isolation at either 30°C or 27°C survived to day 7 following reattachment. Data indicated that the proportion of weight lost by pouch young as a result of isolation decreased with increasing size and age of the pouch young. These trials indicate that it would be possible to harvest very small macropod pouch young from a species in the wild with a very high probability that they would survive short-term isolation from the pouch and reattachment to the teat. The use of this procedure in combination with cross-fostering techniques will allow small pouch young from threatened macropod species to be recruited directly from the wild into captivity, for captive breeding or to improve genetic diversity in captive colonies. It should also act to reactivate diapause embryos in these animals and hence may accelerate breeding in wild-based mothers.

The First Five Years

In 1998 Animal Conservation was launched to provide a new forum for rapid publication of scientifically rigorous studies of conservation biology. It was hoped that articles would draw from a variety of disciplines, ranging from genetics to population biology to behavioural ecology to palaeobiology. Five years on, it is hard to believe that the editorial that accompanied the first issue felt the need to remind people that conservation biology had indeed come of age as a mainstream biological science. The subject is widely taught at universities, fills about a dozen excellent textbooks, and underpins our understanding of a wide variety of high-profile problems from impacts of climate change to loss of biodiversity and management of endangered species and habitats.

A 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.

Lynch & Lande's (1998) comments on our paper (Franklin & Frankham, 1998) misrepresent our purpose, deal largely with a different issue and do not refute our original criticism. Our paper is a commentary on Lande's (1995) suggestion that an effective size of 5000 is required to maintain evolutionary potential, not whether this size ‘is adequate for conservation purposes'.

Conservation breeding for reintroduction is becoming a popular option for restoring threatened populations. Whereas post-release results are widely reported in the conservation literature, little empirical information is presented on the captive populations that often make such releases possible, even though fecundity, fertility and survival rates can have an impact on the outcome and cost of wild population re-establishment. We present results of survival analyses carried out on a captive population of houbara bustards to determine peak periods of mortality, and by identifying sources of variations in mortality to recognize the potential impact of management practices on productivity. There were two main mortality peaks: during incubation (53% survival of fertile eggs), and by 6 months post-hatching (75% survival of hatchlings). Management-related variables influencing survival of eggs and chicks included the year when laid, the cohort of females laying them, and possibly sex. Most post-hatching deaths were due to trauma and infectious diseases. Trauma-related deaths usually follow collisions with cages, and imply selection for the captive environment, an undesirable trend in populations maintained for reintroductions. Reducing losses during incubation would have the largest impact on production of birds for reintroduction, enabling the release of more birds, and reducing the overall costs of the project.

The yellow-eyed penguin is a threatened species endemic to New Zealand and its subantarctic islands. Survival and fledging success vary from year to year partly in response to changing food availability. Mortality in ‘poor food’ years may potentially be reduced if adults are allowed to rear only one of their two chicks. Conservation managers have therefore deliberately reduced broods to one in some recent breeding seasons, but the merits of this policy are controversial. We investigated, by simulation modelling, the conditions under which a policy of artificial brood reduction would enhance population growth. Food supply may be difficult to predict from early-season indicators so we also considered the effect of forecasting errors. Artificial brood reduction can increase the population growth rate, even in the presence of moderate forecasting errors, given a large enough cost of breeding. However, field studies suggest that the required cost of breeding is unrealistically large and the policy is unlikely to be a useful management tool for yellow-eyed penguins.

The brood parasitic brown-headed cowbird (Molothrus ater) is considered an important threat to bird conservation in North America because it reduces the reproduction of its numerous host species. Prior to the colonisation of America by Europeans, the cowbird was largely confined to the North American prairie region, but it has since invaded forests and other habitats and is now one of the continent's most abundant breeding passerines. The objective of this study was to examine cowbird reproduction with different host communities to determine whether habitat-specific reproduction might contribute to the cowbird's population expansion. Cowbird offspring survival was estimated with hosts breeding in fragmented deciduous forest (a newly invaded habitat) and old fields (a habitat more similar to the cowbird's original range). Offspring survival was 1.8–3.1 times higher in forest compared to old fields and was high enough to cause the cowbird population to increase with most forest hosts. The results suggest that increased offspring survival in an invaded habitat facilitates cowbird population growth. Land management for extensive, continuous forests, which cowbirds are known to avoid, could help control the cowbird population and reduce parasitism levels for the >140 species of cowbird hosts.

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

Thirty-eight captive-born suni (Neotragus moschatus) had chromosomal complements of 2n = 52–56 (fn = 60). Variation in diploid number was the result of two centric fusion polymorphisms: a 4;19 fusion and a putative 18;22 fusion. Specimens that were descendants of wild-caught N. m. akeleyi and N. m. zuluensis were 2n = 52 and 56, respectively, but 2n = 53, 54, and 55 cytotypes were probably the result of hybridization in captivity between the two subspecies. Although populations of suni from different geographic regions are phenotypically indistinguishable, cytogenetic differences between N. m. akeleyi and N. m. zuluensis indicate that they should be recognized as distinct management units. Chromosomal variation among our panel of captive-born specimens and evidence of higher perinatal mortality in supposed hybrid cytotypes suggest that these two subspecies be managed as separate populations, particularly with regard to captive breeding, reintroductions, and animal translocations. Insofar as our findings are restricted to the captive population, the cytogenetics of natural populations of suni should be investigated to determine if indeed N. m. akeleyi and N. m. zuluensis have fixed chromosomal differences or if the centric fusion polymorphisms found in captive animals also occur in wild suni.