The demographic relationship between life-history variation and environment may form a foundation for developing conservation strategy. We predicted that grouping 52 North American carnivore species based on life-history modules (reproductive output and reproductive chronology) would highlight differences in adaptations to particular environments. We tested whether differences among life histories related to particular environments classified according to primary productivity and seasonality into a 2 × 2 table. We found that bet-hedgers (e.g., bears, martens, fishers) have evolved life history adaptations to unpredictable environments, marine carnivores (e.g., seals) have evolved highly competitive abilities, and other terrestrial carnivores show adaptations to high reproduction (e.g., neotropical felids and procyonids) or survival (e.g., foxes and skunks). For example, ‘reproducers’ lived in environments with low seasonality and high primary productivity and were characterized by high reproductive output (long gestation, large neonates and small litters), short chronology of reproductive events (early age at maturity and short life), small home ranges and high population density. Conservation measures to promote carnivore populations should differ relative to the type of life history, emphasizing adult survival for bet-hedgers and survivors, and juvenile survival for reproducers and competitors.

Manipulating family sex ratio is often possible, either through non-invasive methods like changing sex-determining ecological or social factors, or through more invasive methods such as hormone treatment of embryos or sperm sexing prior to using assisted reproductive technologies. If the number of available eggs limits population growth, the production of relatively more daughters than sons may eventually lead to increased population growth in terms of absolute numbers. However, any deviation of the effective sex ratio from equality increases the rate of inbreeding and the loss of genetic variance in the next generation. I show here that there is a range of female biased sex ratios where increased population growth outweighs the effect of an enhanced inbreeding rate during the first generation or the first few generations after the start of a sex ratio manipulation programme. This is especially so in small and declining populations, where some sex ratio manipulations not only increase the effective population number Ne, but also shift the population quickly into population numbers that are safe against the Allee effect. Consequently, an optimal sex ratio manipulation with respect to the genetic quality of a population means sending an endangered population first through a genetic bottleneck to achieve increased Ne, and hence decreased rates of inbreeding, in the long run.

A supplementary feeding and predator removal experiment was conducted on the hen harrier population on West Mainland, Orkney, to test whether increased predation pressure or shortage of food was responsible for the poor breeding success and potentially the decline of this population. Although numbers of crows appeared to have increased since 1983, the removal of hooded crows from breeding territories of male harriers had no detectable effect on any of the breeding parameters measured. The provision of supplementary food to male harriers significantly increased their numbers of breeding females, but had no detectable effect on either lay date, clutch size or hatching success. Results suggest that the current low levels of polygyny are a consequence of a shortage of food during the pre-lay period. Conservation management for this species should therefore be directed towards increasing the harriers' food supply, especially during the pre-lay period.

Numbers of free-ranging dogs (Canis familiaris) have reached unprecedented levels in Zimbabwean communal lands (agropastoralist rural areas). This study examined the potential competitive interactions between dogs and wild scavengers on the boundary of Gokwe Communal Land (GCL) and the Sengwa Wildlife Research Area (SWRA) in 1995-96. Dietary studies showed that dogs were primarily scavengers of human waste and animal carcasses. Twelve experimental carcasses indicated that dogs were the most successful species in the vertebrate scavenger guild, consuming 60% of available biomass and finding 66.7% of carcasses. Dogs monopolized the supply of domestic animal carrion within GCL, but also consumed wild carrion up to 1 km within the SWRA, and were seen 3 km inside the reserve. Their principal competitors for carcasses were vultures, and to a lesser degree lions (Panthera leo), leopards (P. pardus) and spotted hyaenas (Crocuta crocuta). Dogs outcompete vultures on wildlife reserve boundaries owing to their high densities, nocturnal and diurnal activity, physical dominance and greater tolerance of human disturbance. With a population growth rate of 6.5% per annum the influence of dogs will intensify on the peripheries of reserves, exacerbating their existing threat to wild scavengers. This scenario is probably occurring in many other African countries.

The Mexican gray wolf appears to be extinct in the wild and exists now only in captivity and as a reintroduced population in southeast Arizona and southwest New Mexico. A recent study did not find evidence for inbreeding depression in juvenile viability or litter size in captive animals. Here we found that captive wolves with little or no known inbreeding had lower body size than wild-caught wolves. In addition, captive wolves with higher inbreeding had lower body size than captive wolves with little or no inbreeding. The captive population was descended from three founders until two other lineages, each descended from two founders, were recently added to the population. There has been concern that the offspring from matings between these lineages may differ from the individuals in the original lineage so we examined the potential statistical power to detect differences between body size for animals from cross-lineage matings and other matings. In endangered species there are often limited opportunities to obtain sample sizes large enough to detect statistically significant differences because of the extensive resources needed to produce and maintain captive animals. In this case, however, it appears from our examination that in the next few years there will be an adequate sample size to evaluate statistically the differences in body size between these groups.

As metapopulation dynamics is thought to play an important role in the conservation of mammals, mainly owing to the fragmentation process, a Population Viability Analysis (PVA) was used to evaluate the role and importance of individual patches to the metapopulation persistence of the long-furred wooly mouse opossum, Micoureus demerarae, a neotropical arboreal marsupial. The metapopulation under study comprises eight small Atlantic Forest patches at Poço das Antas Biological Reserve, southeastern Brazil. The analysis indicates that the local populations may be divided into three groups: (1) in the smallest and most isolated patches, where they are the most endangered, (2) in five circular-shaped and relatively well-connected patches and (3) in the largest patch with the most persistent local population. Knowledge of how specific patches influence metapopulation dynamics is an important tool in guiding management strategies, and dynamics can be affected by factors like patch size and relative position. It seems that for this particular case, probability of metapopulation extinction, mean metapopulation size, heterozygosity and mean growth rate were the most informative measures to evaluate a patch's contribution to metapopulation persistence. Despite all controversies, metapopulation theory, when carefully and properly applied, is a valuable tool in conservation biology.

Inbreeding depression is a critical phenomenon for conservation of small populations, especially concerning the captive breeding of endangered animals whose effective population size may be very low. In order to manage such captive populations on a long-term basis, assessment of the interactions between demographic and genetic parameters and their consequences on the population survival probability is essential. Therefore, we examined (1) the relative importance of initial population size and carrying capacity on the survival probability of a population, (2) the impact of a bottleneck in an already inbred population. For this purpose, a stochastic model taking into account the effect of genes responsible for inbreeding depression was built. It was concluded that the population survival probability is very sensitive to the carrying capacity. Moreover, in inbred populations, a large increase in the extinction rate results from a second bottleneck. With two founders, survival is high as long as the carrying capacity is not very small (above a few decades), whereas a second bottleneck has a dramatic effect, even when the carrying capacity approaches 100. Consequently, previous inbreeding should be considered in the case of reintroduction. Reason for reintroduction failure could be successive bottlenecks, with the associated deleterious effects of inbreeding.

Species diversity and community structure indices (richness, diversity and evenness) are typically derived from contemporary biological survey atlases to identify conservation areas or to determine macroecological-environment relationships. Surprisingly, there are few studies based on national taxa surveys that describe and measure the influence human disturbance patterns may have on these ecological measures. This study uses various spatial statistical methods to examine and model large-scale spatial structure in diversity, structure indices derived from a comprehensive bird atlas, and composite variables of environment and human land transformation. Data were derived from an atlas of South African birds and segregated into five vegetation biomes. For each sample location, environmental and land-use data were used to calculate composite environmental gradients in climate, topography and human land transformation. Semivariograms were used to detect large-scale trends and spatial scale, and Moran's I statistic correlograms to test for large-scale spatial autocorrelation in detrended diversity indices. Ordinary least squares regressions for all biomes indicated a significant positive relationship between high levels of human transformation and species diversity, whereas high transformation had a significant negative influence on evenness. These same relationships held for the majority of biomes after the effects of environmental gradients were removed. The analysis also shows that in areas with favourable environmental resource levels, diversity for birds increases. These areas also tend to contain a large proportion of highly transformed land, and evenness decreases in the woodland, grassland, Karoo and fynbos biomes. This suggests that high-intensity transformation may bring in novel resources for birds not normally found in some of the biomes, with some species adept at exploiting these changes and reaching high densities with a tendency for assemblage structure to drift towards single species dominance. The results imply that species data derived from contemporary atlases may begin to demonstrate the effects of human influence on ecological measures rather than only indicating the effects of environmental variation on community structure.

Approximately 40% of the world's leatherback marine turtles (Dermochelys coriacea) nest in Suriname and French Guiana. Trends in nest numbers reconstructed for the last 34 years indicate several up and down events. We undertook computer simulations to determine whether a density-dependent phenomenon might be involved because the period of high-density nesting coincides with a high level of nest destruction by nesting females. The parameters of density-dependent nest destruction were calculated for the Yalimapo-Awala beach. We show that: (1) density-dependent nest destruction occurs, but (2) it promotes a density-dependent feminization of hatchling sex ratio, and consequently (3) the global production of juveniles continues to increase in relation with the increasing number of deposited nests even for the highest densities observed at that beach. Mean annual production of female hatchlings per adult female, although density dependent, is less than two juveniles even at the lowest densities of nesting females.

Some errors occurred within Table 3 for which the publishers would like to apologise to their readers and the authors. The corrected Table 3 is below