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.

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.

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.

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.

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.

The importance of diseases of domestic animals in the conservation of wildlife is increasingly being recognised. Wild carnivores are susceptible to many of the pathogens carried by domestic dogs and cats and some of these pathogens have caused disease outbreaks and severe population declines in threatened species. The risk of disease spillover from domestic to wild carnivores in South America has not been extensively investigated. This study examined the disease exposure of domestic carnivores living near a protected area in Bolivia. Forty dogs and 14 cats living in three towns on the eastern border of Madidi National Park were sampled. High levels of exposure to canine distemper virus, canine parvovirus, Sarcoptes scabiei and Toxoplasma gondii were found among domestic dogs, with similarly high levels of exposure to feline parvovirus, feline calicivirus and T. gondii being found among domestic cats. If contact occurs between domestic and wild carnivores, disease spillover may represent an important risk for the persistence of wild carnivores in the region. Additional research is therefore necessary to determine if wild carnivores living in proximity to these domestic carnivore populations are being exposed to these pathogens.

Conservation planning and practice rely heavily on abundance information generated at local scales for decision-making. Unfortunately most distributional data are only provided as presence–absence records at regional or national scales and cannot be used for making local conservation decisions. To date, two methods have been proposed for estimating local abundances and area of occupancy from coarse-scale presence–absence data. Kunin (1998) proposed the use of the fractal method, which assumes that species distributions are self-similar across scales. He & Gaston (2000a), in turn, proposed the use of the negative binomial distribution (NBD) for estimating abundances from presence–absence data collected at different scales. Previously only plant data were used to test these models. In the present study, they were tested using distributional presence–absence, as well as abundance data for a selection of large herbivores that have a restricted distribution in the Kruger National Park, South Africa. The results illustrate that the fractal method tends to overestimate areas of occupancy, while the NBD method underestimates the areas of occupancy of all species. This means that there were significant differences between the predictions provided by the two methods. Both these methods rely on the relationship between the area of occupancy and the size of the area over which the survey is conducted, but describe this relationship in a different way. These techniques could prove useful in the field of conservation biology and this study illustrates that these methods can be used on large mammal species and deliver results that are consistent with previous studies on plants.

Flagship species are charismatic species that serve as a symbol and rallying point to stimulate conservation awareness and action but are often used synonymously as de facto umbrella species to delineate reserve boundaries. We tested the extent to which the presence of a flagship species would protect other ‘background species’ at the local scale at which practical decisions about small reserves are often made. Using long term sightings, we identified four 1 km2 sites that are frequently visited by jaguars and by tapirs (flagship species), and by white-lipped peccaries and spider monkeys (non-flagship species) in neotropical rainforest in Belize. We then made inventories of five vertebrate taxonomic groups at each site. We found no consistent differences in species richness or abundances of frogs, phyllostomid bats, terrestrial mammals, scansorial mammals or birds across the four sites, except that frog diversity and abundance was higher close to a river at the flagship site where tapirs were found. Since these classic Latin American flagship species fail to encompass particularly high numbers or abundances of vertebrate species at a local scale, they appear to be a poor conservation tool when co-opted as umbrella species for delineating the location of very small reserves in the neotropics.

Most large native carnivores have experienced range contractions due to conflicts with humans, although neither rates of spatial collapse nor expansion have been well characterised. In North America, the grizzly bear (Ursus arctos) once ranged from Mexico northward to Alaska, however its range in the continental USA has been reduced by 95–98%. Under the U. S. Endangered Species Act, the Yellowstone grizzly bear population has re-colonised habitats outside Yellowstone National Park. We analysed historical and current records, including data on radio-collared bears, (1) to evaluate changes in grizzly bear distribution in the southern Greater Yellowstone Ecosystem (GYE) over a 100-year period, (2) to utilise historical rates of re-colonisation to project future expansion trends and (3) to evaluate the reality of future expansion based on human limitations and land use. Analysis of distribution in 20-year increments reflects range reduction from south to north (1900–1940) and expansion to the south (1940–2000). Expansion was exponential and the area occupied by grizzly bears doubled approximately every 20 years. A complementary analysis of bear occurrence in Grand Teton National Park also suggests an unprecedented period of rapid expansion during the last 20–30 years. The grizzly bear population currently has re-occupied about 50% of the southern GYE. Based on assumptions of continued protection and ecological stasis, our model suggests total occupancy in 25 years. Alternatively, extrapolation of linear expansion rates from the period prior to protection suggests total occupancy could take >100 years. Analyses of historical trends can be useful as a restoration tool because they enable a framework and timeline to be constructed to pre-emptively address the social challenges affecting future carnivore recovery.

Effective representation of all species in local conservation planning is a major challenge, particularly in poorly known but highly fragmented biological ‘hotspots’. Based on 105 months of studies over 49 years, we reviewed the status of 915 species and 910 subspecies of butterflies known in the Philippines. We identified 133 globally threatened and conservation-dependent endemic Philippine taxa. The current system of 18 priority protected areas provides at least one protected area for 65 of these but no areas for 29 species and 39 subspecies. Of the 133 taxa, 71% do not have a stable population inside a priority site. A total of 29 taxa is endangered or critically endangered; 83% of these do not occur within a priority site. Least protected are the lowland taxa. The minimum network required to include each threatened and conservation-dependent taxon of butterfly within at least one area would comprise 29 sites. The Sulus and Mindanao hold disproportionate numbers of threatened butterflies. Our findings suggest limited cross-taxon congruence in complementarity-derived priority sets. A large proportion of the priority areas for Philippine butterflies do not coincide with known priority areas for mammals and birds. We demonstrate that a better resolved species level classification could reveal numerous ‘new’ priority areas. In tropical island and mountain regions where the distinctiveness of butterfly subspecies is high, significant evolutionary units may be lost unless fine-scale conservation planning pays attention to well-defined subspecies.

Management strategies that attempt to mitigate tropical biodiversity loss require detailed studies of biodiversity in different land-uses. In this study the community structure and species richness of songbirds was characterised along with the vegetation structure, in three land-use types in and around a tropical forest reserve in Uganda (intact, mature forest; regenerating secondary forest; smallholder agriculture). Each land-use type had 30–35 count stations that were sampled twice by means of a 15-min recording session. In total, 118 bird species were recorded from 192 station counts. Number of species/station was similar in intact and regenerating forest and lower in smallholder agriculture. Songbird communities in intact forest were highly distinct from those in smallholder agriculture and were composed of forest-dependent species. Communities in regenerating forest were intermediate between intact forest and agriculture, although much closer to intact forest. Generalised Linear Model (GLM) modelling revealed that tree density and distance to the nearest intact forest had strong positive and non-linear effects on the community composition and forest species richness of songbirds. Simulations using these models showed that agroforestry programmes would not raise tree densities to levels that would shift agricultural songbird communities towards forest communities. Current and best-case agricultural practices are therefore unlikely to contribute to the conservation of the songbird component of forest biodiversity in this area.

The Owston's palm civet (Chrotogale owstoni) is one of the least known viverrids. In order to assess the degree of intraspecific variation, we sequenced a fragment of mitochondrial cytochrome b in 26 individuals. We identified 23 haplotypes, indicating a fairly high level of genetic diversity. The phylogenetic analysis yielded two clades supported by eight synapomorphies, suggestive of a north/south geographical divide. Recommendations for captive management cannot be made on the basis of the study results, but the high level of genetic diversity is very encouraging for both field conservation and captive breeding efforts.