Adequate monitoring of amphibian populations will be increasingly important if global declines are to be understood and, where possible, reversed. The natterjack toad, Bufo calamita, is the rarest British amphibian and has been the subject of substantial conservation efforts. Monitoring strategies have aimed to quantify both the total numbers of populations and the status of individual populations. Between 1970–1999 the number of natterjack populations increased from 43 to 48 because successful translocations (11) outnumbered extinctions (6). Efforts to monitor individual populations increased over the period 1970–1999. Between 1990–1999 there were no detectable trends in B. calamita population size or breeding success in Britain, although power to detect any trends over 10 years was low. Calling activity and short-term trends in spawn counts were unreliable predictors of long-term population viability in the absence of extra information such as toadlet production. Long periods (> 10 years) of spawn counts are needed to demonstrate trends that are reflective of real population changes at the national level. Efforts to develop reliable methods for monitoring B. calamita in Britain could provide useful guidelines for work on some other declining species of amphibians.

The relationship between population size and temporal variability in population size was examined using 2387 populations of 203 species from the Global Population Dynamics Database. Population variability, relative to population size, was assayed by regressing the standard deviation of population size against mean population size. Linear regression produced slopes that were less than one in 165 of 203 species. Thus, temporal fluctuations in population size became significantly weaker as population size increased. Similarly, the slope was significantly less than one for a single regression including all 2387 populations, regardless of taxonomic classification. The slopes of the regression lines did not differ for major taxonomic groupings, but the Y-intercept was significantly lower for birds than for the other taxonomic groupings. Factor analysis was used to examine the highly correlated parameters: data reliability, population size and taxonomic lineage. Population size was obviously the most important parameter affecting temporal variation in population size, data reliability was also very important, but taxonomy was of little or no importance. The relationship between temporal variation in population size and mean population size, predicted from the data, was used to predict the probability of extinction assuming a normal distribution of population sizes. This simple model predicts that populations of vertebrates will have to number in the thousands for long-term conservation to be effective.

Management of marine species has increasingly focused on key site protection. Initiatives to protect bottlenose dolphins, Tursiops truncatus, under the EU Habitats Directive reflect this trend. The boundaries of the Moray Firth candidate Special Area of Conservation (cSAC) were intended to include the main Scottish population's core range, following research conducted in the 1980s and early 1990s. However, during implementation, anecdotal sightings increased outside the cSAC. Here, the authors examine existing datasets to identify whether these reports reflect simply elevated awareness among public observers or real changes in distribution. Dolphins photo-identified in areas originally considered to be outside the population's range confirmed they originated from the protected population. These individuals became rarer within the cSAC during the 1990s. Scottish bottlenose dolphins kill harbour porpoises, Phocoena phocoena, and carcasses from these interactions also became more frequent outside the cSAC during the 1990s. These results indicate mobility of this ‘resident’ dolphin population on a timescale similar to that of the implementation of the European Directive designed to protect it. Consequently, this and other similar designations, may afford less protection than originally envisioned and the authors recommend, therefore, that the potential for long-term mobility should be actively incorporated into such management structures from the outset.

The conservation of migratory species can be problematic because of their requirements for large protected areas. We investigated this issue by examining the annual movements of the migratory wildebeest, Connochaetes taurinus, in the 25000 km2 Serengeti-Mara Ecosystem of Tanzania and Kenya. We used Global Positioning System telemetry to track eight wildebeest during 1999–2000 in relation to protected area status in different parts of the ecosystem. The collared wildebeest spent 90% of their time within well-protected core areas. However, two sections of the wildebeest migration route – the Ikoma Open Area and the Mara Group Ranches – currently receive limited protection and are threatened by poaching or agriculture. Comparison of current wildebeest migration routes to those recorded during 1971–73 indicates that the western buffer zones appear to be used more extensively than in the past. This tentative conclusion has important repercussions for management and needs further study. The current development of community-run Wildlife Management Areas as additional buffer zones around the Serengeti represents an important step in the conservation of this UNESCO World Heritage Site. This study demonstrates that detailed knowledge of movement of migratory species is required to plan effective conservation action.

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.

The natural morphological variation in the wildcat, Felis silvestris, and morphological changes possibly caused by introgressive hybridisation with the domestic cat, F. catus, were examined, based on up to 39 variables concerning cranial morphology. The samples of wild-living cats originated from Scotland and southern Africa and consisted of both classical wildcat and other pelage types. Principal component and cluster analyses suggested that introgressive hybridisation occurred in both areas, with the consequence that the characteristics of local wildcat populations had been altered in terms of the frequencies of occurrence of certain characters, especially those concerning cranial capacity. In both regions the clustering patterns of wild-living cats can be interpreted as containing four main groups. One of these consisted mainly of ‘non-wildcats’ and groups furthest from the ‘non-wild’ cluster consisted of the highest proportion of ‘wildcats’ (c. 80%). We propose that where a population is heavily introgressed, the only feasible way to define a wildcat is on the basis of inter-correlated features and conservationists must take a population-based approach to assess the extent of introgression. This approach may provide an operational standard for assessing the impact of hybridisation between wildcats and domestic cats throughout the species' range; it suggests that the Scottish wildcats may be critically endangered.

There is recent evidence to suggest that domestic livestock deplete the density and diversity of wild herbivores in the cold deserts of the Trans-Himalaya by imposing resource limitations. To ascertain the degree and nature of threats faced by Himalayan ibex (Capra sibirica) from seven livestock species, we studied their resource use patterns over space, habitat and food dimensions in the pastures of Pin Valley National Park in the Spiti region of the Indian Himalaya. Species diet profiles were obtained by direct observations. We assessed the similarity in habitat use and diets of ibex and livestock using Non-Metric Multidimensional Scaling. We estimated the influence of the spatial distribution of livestock on habitat and diet choice of ibex by examining their co-occurrence patterns in cells overlaid on the pastures. The observed co-occurrence of ibex and livestock in cells was compared with null-models generated through Monte Carlo simulations. The results suggest that goats and sheep impose resource limitations on ibex and exclude them from certain pastures. In the remaining suitable habitat, ibex share forage with horses. Ibex remained relatively unaffected by other livestock such as yaks, donkeys and cattle. However, most livestock removed large amounts of forage from the pastures (nearly 250 kg of dry matter/day by certain species), thereby reducing forage availability for ibex. Pertinent conservation issues are discussed in the light of multiple-use of parks and current socio-economic transitions in the region, which call for integrating social and ecological feedback into management planning.

Maintenance of genetic diversity is critical for the preservation of small populations. Most captive populations are small and managers focus their efforts on reducing extinction risks by minimising loss of genetic diversity. To project changes in genetic diversity, managers use a genetic drift model. We used data from 40 managed captive populations to test whether this drift model is a good predictor of change in genetic diversity by comparing projected 10-year trajectories of annual loss in expected heterozygosity with the changes estimated from pedigree analysis. We found that the drift model frequently overestimated the rate at which genetic diversity would be lost and could not predict increases, which we observed in 22 species. We suggest that the drift model does not adequately reflect the potential for management strategies, such as prioritised breeding recommendations and recruitment of potential founders, to slow the loss of genetic diversity. In many cases, the drift model may be overly pessimistic, leading managers to seek solutions such as importation, increased population size or the abandonment of a captive population, that may be unnecessary or premature. Managers should be cautious when interpreting results from genetic drift models, taking care to assess how management actions might lead to more optimistic prognoses.

The endemic pink pigeon has recovered from less than 20 birds in the mid-1970s to 355 free-living individuals in 2003. A major concern for the species' recovery has been the potential genetic problem of inbreeding. Captive pink pigeons bred for reintroduction were managed to maximise founder representation and minimise inbreeding. In this paper, we quantify the effect of inbreeding on survival and reproductive parameters in captive and wild populations and quantify DNA sequence variation in the mitochondrial d-loop region for pink pigeon founders. Inbreeding affected egg fertility, squab, juvenile and adult survival, but effects were strongest in highly inbred birds (F≥0.25). Inbreeding depression was more apparent in free-living birds where even moderate levels of inbreeding affected survival, although highly inbred birds were equally compromised in both captive and wild populations. Mitochondrial DNA haplotypic diversity in pink pigeon founders is low, suggesting that background inbreeding is contributing to low fertility and depressed productivity in this species, as well as comparable survival of some groups of non-inbred and nominally inbred birds. Management of wild populations has boosted population growth and may be required long-term to offset the negative effects of inbreeding depression and enhance the species' survival.

An important challenge in conservation biology is extracting pertinent information from the available data for endangered species. Rarely do we have enough information to precisely determine an organism's risk of extinction and other factors that affect its management. How, then, can we use limited information to make responsible conservation decisions on controversial species such as the Mount Graham red squirrel? We used several analytical approaches to examine 15 years of abundance data for the Mount Graham red squirrel in order to propose recovery criteria and to evaluate alternative conservation strategies. We analysed the historical population dynamics using a diffusion approximation model and showed that the main threat to the population was not the overall growth rate (which may well be greater than 1) but rather the wide range of variation in annual growth rates. We used information on the distribution of growth rates and abundance to classify the species as threatened under the Endangered Species Act (ESA). We then presented a simple demographic model to examine the effects of proportional changes in vital rates on the population growth rate (λ). The elasticity values obtained for Mount Graham red squirrels indicate that the population is far more sensitive to changes in survival rates (particularly adult survival) compared to reproduction. Our analyses suggest that management should focus on refining monitoring techniques, reducing sources of variability, improving the survival of adult animals and filling the gaps in the currently available data.

Wildlife capture and trade for traditional use in Papua New Guinea has led to the extirpation of cassowary in some areas and increasing pressure for trade from areas where they remain. We tested a village-based monitoring programme to evaluate sustainability of wildlife capture and trade by households in the Crater Mountain Wildlife Management Area. We monitored the type and number of wildlife species captured and traded. For the most heavily traded species, dwarf cassowary, we compared estimated annual offtake of live cassowary to maximum sustainable offtake and also compared change in hunter effort over time. We found that live offtake rates of 0.06–0.07/km2 were unsustainable in one village catchment and on the threshold of unsustainable use in another. Extirpation of cassowary will probably occur in the management area unless the location or quantity of the harvest can be restricted and the husbandry of captive birds improved. Results indicate that village monitoring of cassowary offtake is feasible when done in collaboration with outside, trained observers. Such monitoring should be encouraged as a means for landowners and management agencies to collectively evaluate the sustainability of the cassowary harvest in Papua New Guinea. This study provides an example of how scientists working with local communities in tropical forests can contribute to systematic monitoring and evaluation of wildlife offtake for sustainable use.

The unique butterfly species, Baronia brevicornis, perhaps the oldest taxon in the Papilionidae, is known to have a very restricted distribution in Mexico. Populations are restricted to southern Mexico in deciduous scrub forest where its host-plants, Acacia trees (Leguminosae), are common and widespread. Little is known of the conservation implications of its relationship with its host trees. We recorded fine scale population data for larval and adult B. brevicornis in 22 km2 of fragmented landscape in southern Mexico. Habitat associations determined from over 1319 transect walks reveal that B. brevicornis exhibited an extremely localised distribution, occupying < 1% of the study area and being mostly associated with Acacia woodlots. Detailed analyses of habitat requirements for larva and/or adult B. brevicornis suggest that it lays its eggs on Acacia pennatula and A. macracantha (two newly recorded larval host-plants), that eggs were laid disproportionately on Acacia trees with long branches (χ2 = 17.7, P < 0.001) and that the probability of finding adult B. brevicornis between occupied and un-occupied Acacia woodlots increased with host-plant density (χ2 = 18.4, P < 0.001). The results of this study suggest that conservation recommendations for B. brevicornis must consider the condition of the Acacia habitat network, given that Acacia is mostly associated with human-managed grazing systems. Effective conservation will require the establishment of connected networks of patches where natural dynamics can produce new habitats, as well as the creation of new habitats within colonisation distance. This research provides a rare case study of conservation biology of a Neotropical insect, emphasising the importance of using ecological information to provide management recommendations.

Between 1990 and 1992, Mediterranean striped dolphins (Stenella coeruleoalba) suffered high mortality due to a morbillivirus epidemic. Ten highly variable microsatellite markers were used to assess the population structure of a sample of these stranded animals and to assess the genetic consequences of the epizootic on present stocks. We found little evidence of population structure within the Mediterranean, but distinct separation between this and the North Sea (Atlantic) population, the latter also showing greater genetic diversity. Using a genetic measure of inbreeding, we found that dolphins dying early in the outbreak were significantly more inbred than those dying later. Within 10 years of the end of the epidemic, the level of inbreeding among stranded dolphins had returned to its pre-outbreak levels. However, on average all stranded animals showed elevated levels of inbreeding, suggesting that animals dying from disease may venture towards the shore more than those dying of old age. Our results imply an important role for inbreeding in the dynamics of disease spread and that, in marine mammal research, caution should be exercised when inferring demographic parameters from stranded specimens.

Camera trapping has recently been introduced as an unbiased and practical method for monitoring tiger abundance. In a high density area in the Royal Bardia National Park in lowland Nepal, we tested this method by trapping very intensively within a 25 km2 area to determine the true number of animals in that area. We then tested the effect of study design by sub-sampling the data set using varying distances between trap stations and by reducing the number of trapping nights at each station. We compared these numbers with the density estimates generated by the capture–recapture models of the program CAPTURE. Both distance between traps and trapping duration greatly influenced the results. For example, increasing the inter-trap distance from 1 to 2.1 km and reducing the trapping duration per station from 15 to 10 nights reduced the number of tigers captured by 25%. A significant decrease in trapping rates during successive 5-night periods suggested that our tigers became trap-shy, probably because of the photo flash and because they detected the camera traps from cues from impression pads 50 m from the traps. A significant behavioural response was also confirmed by the program CAPTURE. The best capture–recapture model selected by the computer program (Mbh) gave precise estimates from data collected by the initial 1 km spacing of traps. However, when we omitted data from half the number of traps, thus decreasing the sampling effort to a more realistic level for monitoring purposes, the program CAPTURE underestimated the true number of tigers. Most probably, this was due to a combination of trap shyness and the way the study was designed. Within larger protected areas, total count from intensive, stratified subsampling is suggested as a complementary technique to the capture–recapture method, since it circumvents the problem of trap shyness.

The Greater Chassahowitzka black bear population is the smallest documented in North America with fewer than 20 individuals. Its future depends on landscape linkages with other bear populations that are separated by denatured habitat. We used a Geographic Information System (GIS) to identify potential landscape linkages between this isolated population and six others in Florida. Pathway lengths ranged from 60–194 km with varying potentials for facilitating black bear dispersal. Each pathway incorporated 35Ð88% conservation land and encountered at least 11 dispersal bottlenecks. Even pathways that incorporated extensive conservation land encountered bottlenecks that make these linkages potentially unviable. All six pathways, however, passed through ≥95% core black bear habitat. Thus, the infrastructure for a conservation network is still largely intact. The Suwannee pathway provides the best opportunity to restore connectivity between the Greater Chassahowitzka Ecosystem (GCE) and a southward colonising bear population in the Big Bend region. However, intensification of development poses an immediate threat to maintaining connectivity between the GCE and other bear populations in Florida. Through immediate strategic planning and active conservation and restoration measures, many of the generated pathways can provide long-term connectivity. Least-cost path analyses can aid in the conservation of wide-ranging animals by providing managers with a science-based, empirically derived blueprint of potential landscape linkages.

There have been few contemporary extinctions in the sea, which suggests marine species are either less vulnerable to extinction than terrestrial species, or marine extinctions may have gone unnoticed. We consider whether a large conspicuous reef fish, the giant humphead parrotfish (Bolbometopon muricatum), is likely to have declined across much of its geographical range. Informal knowledge was used to determine the status of the giant humphead parrotfish. We first surveyed fishers' knowledge of this parrotfish at 12 lightly exploited islands in the Lau group, Fiji and then compiled a global inventory of available information. In the Lau islands, Fiji, fishers reported this parrotfish as previously abundant, but it had not been caught at six islands since at least 1990 and was considered rare at another four islands. The parrotfish had been captured recently (since the 1990s) at three islands where fishers did not target parrotfishes regularly. A compilation of giant humphead parrotfish records provided by local scientists at 39 locations in 31 Indo-Pacific nations suggested this fish is locally common only inside areas where fishing is prohibited and that it is currently globally rare. Local densities of the giant humphead parrotfish were negatively correlated to a categorical scale of fishing pressure across six Indo-Pacific locations. The retrospective discovery of local disappearances and global rarity of a distinctive and formerly prominent reef fish is consistent with the hypothesis that the capacity to detect disappearances of exploitation-vulnerable species in the sea is lower than expected.

Because of the difficulties encountered in detecting many large tropical forest-dwelling species in their natural habitat, precise figures concerning the distribution, number and trends of many populations remain deficient. In tropical forests, ground surveys are generally carried out by counting objects along straight lines. These counts require a strict compliance with the line-transect methodology before (proper design of the census), during (careful data collection) and after (accurate and correct data processing and analysis) the census itself. In addition, the major source of bias when estimating population size and/or trends comes from the extrapolation of estimates obtained in small sampling areas to the larger, and often incompletely known, distribution of the population. In the Kinabatangan floodplain (Sabah, Malaysia), helicopter surveys were useful in directly assessing the distribution of orang-utans and were a major advantage in the precise estimation of the size of the orang-utan population surviving in this region. Our survey showed that about 1100 orang-utans remain in the multiple-use forests of the Kinabatangan floodplain. These results provide new evidence on orang-utan adaptation to habitat disturbance and indicate the potential of the Kinabatangan multiple-use forests for orang-utan conservation. Helicopter surveys appear to be a promising alternative to ground survey for precise distribution assessment and for monitoring population trends of apes throughout their entire range in Asia and in some parts of Africa.

Darwin's fox (Pseudalopex fulvipes) is known to survive only on Chiloé Island off the coast of southern Chile and in Nahuelbuta National Park, 600 km to the north in mainland Chile. The Valdivian coastal forest, in which the Darwin's fox lives, historically spanned from Nahuelbuta National Park southward past Chiloé Island on the mainland. Furthermore, the forest on Chiloé Island was connected to the mainland forest by a land bridge for much of the Pleistocene. Thus, the distribution of Valdivian forest suggests that the historic range of Darwin's fox may have been much larger. We searched the remnant pockets of coastal forest on mainland Chile using live traps, non-invasive techniques and interviews to look for new populations of the critically endangered Darwin's fox. Although no Darwin's fox was captured, evidence of a new population near Punta Chanchán was found.

The impact of introduced herbivores on the composition and structure of plant communities has been widely studied. However, little is known about how they affect wildlife. We studied the impact of feral horses under different grazing regimes on the communities of birds in a nature reserve in the Pampas grasslands in Argentina. The areas that had predominantly tall grass (enclosures and areas of moderate grazing intensity) showed the greatest species richness and total abundance of birds. Some species, e.g. the southern lapwing (Vanellus chilensis), were associated with the presence of horses, while others, e.g. pipits (Anthus spp), were more common in lesser grazed areas. The presence of feral horses was associated with an increase in the rate of predation of eggs which varied from 12.5% within the enclosures to 70% in grazed areas. It is suggested that the increase in predation rate was due to the increased visibility of the nests and an increase in the density of opportunist carnivores. Small areas of grassland in a good state of conservation could serve as sources that would maintain communities of birds in the more transformed sections.

Species conservation may be complicated in symbiotic interactions. Sub-lethal impacts of human activities on one species may be lethal to other species on which they depend. We investigated the impact of two aspects of eutrophication – changes in phytoplankton and oxygen levels – on the interaction between a freshwater fish that is endangered in several countries, the European bitterling, Rhodeus sericeus, and the unionid mussel hosts that they require for spawning. Reduced concentrations of algae and oxygen each led to a greater proportion of bitterling embryos being ejected prematurely from the mussel hosts. Reduced algal concentrations also led to reductions in mussel ventilation rates and to mussels spending less time with their valves open. Bitterling mortality may have been due to three causes: direct effects of environmental conditions on embryonic survival, active expulsion by mussels when stressed and through responses by mussels that created internal conditions that bitterling embryos could not survive. Our study shows that the sub-lethal effects of pollution on one species can have lethal effects on another species with which it interacts. Such interactions need to be considered in conservation programmes.