We examine the abundance and distribution of Sumatran tigers (Panthera tigris sumatrae) and nine prey species in Bukit Barisan Selatan National Park on Sumatra, Indonesia. Our study is the first to demonstrate that the relative abundance of tigers and their prey, as measured by camera traps, is directly related to independently derived estimates of densities for these species. The tiger population in the park is estimated at 40-43 individuals. Results indicate that illegal hunting of prey and tigers, measured as a function of human density within 10 km of the park, is primarily responsible for observed patterns of abundance, and that habitat loss is an increasingly serious problem. Abundance of tigers, two mouse deer (Tragulus spp.), pigs (Sus scrofa) and Sambar deer (Cervus unicolor) was more than four times higher in areas with low human population density, while densities of red muntjac (Muntiacus muntjac) and pigtail macaques (Macaca nemestrina) were twice as high. Malay tapir (Tapirus indicus) and argus pheasant (Argusianus argus), species infrequently hunted, had higher indices of relative abundance in areas with high human density. Edge effects associated with park boundaries were not a significant factor in abundance of tigers or prey once human density was considered. Tigers in Bukit Barisan Selatan National Park, and probably other protected areas throughout Sumatra, are in imminent danger of extinction unless trends in hunting and deforestation are reversed.

The Egyptian vulture (Neophron percnopterus) breeds in Sicily and, in 22 years of monitoring, has shown a decline followed by a slight recovery. We used Generalised Linear Models to predict: (1) the distribution range, (2) the habitat selection within the range, (3) the quality (i.e., occupation rate, breeding success) of breeding sites. Some 60% of Sicily proved to be unsuitable, being either too densely forested and without cliffs for nesting, or too densely populated, along with intensive agriculture. The models converged, indicating that the pairs select a precise upland habitat where low cliffs, distant from urban areas, are surrounded by arboreal crops and Mediterranean vegetation. The variables predicting the quality of a site are also related to human disturbance, including the distance from a road or the presence of heavy traffic. Natural restocking, in the last 3 years, is occurring in quiet sites and in proximity to extensive grazing land rich in sheep and goat herds. These results focused on short-term programmes for local management of the species aimed at protracting the natural restocking: namely, the activation of (1) a stable system of artificial feeding stations, (2) nest site protection with joint activities for increasing public awareness, (3) a reintroduction project, by hacking, of juveniles born in captivity in Italian and European breeding centres.

A companion paper in this issue describes the mapping of Cape Sable seaside sparrow (Ammodramus maritimus mirabilis) habitat using satellite imagery. In general, those maps are correct. However, testing against an independent survey of the sparrow population does identify errors. Those errors fall into two categories, model errors and bird errors. The model errors result from genuine problems with the model. More interesting for conservation are the bird errors, which are more numerous. They are of two types. (1) Commission errors: some suitable habitat does not contain birds. These are areas where prior events have depleted sparrow numbers, but because the sparrows do not disperse long distances, they cannot occupy it quickly. (2) Omission errors: some birds remain in unsuitable habitat that was formerly suitable. This results from the sparrow's very high site fidelity. Often, they will not leave an area even when it is no longer suitable. The consequences of these bird errors are that some habitat and some birds are not contributing to the species' survival. Thus, an estimate of only the amount of habitat or only the sparrow population may present an overly optimistic view of the sparrow's plight.

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.

Giant tortoises once thrived throughout the Galápagos archipelago, but today three island populations are extinct, only one individual survives from the island of Pinta, and several populations are critically endangered. We established the geographic origin of 59 captive tortoises housed at the Charles Darwin Research Station in the Galápagos Islands in an effort to find a mate for the sole survivor from Pinta (‘Lonesome George’) and to augment the number of breeders in other imperilled populations. By comparison with an extensive database of mtDNA control region (CR) haplotypes and nine microsatellites, we determined the geographic and evolutionary origin of the captive individuals. All individuals had CR haplotypes and multilocus microsatellite genotypes identical to or closely related to known haplotypes from natural populations. No obvious mate was found for Lonesome George, although we found several captive individuals carrying an evolutionarily close but geographically distinct mtDNA haplotype. Tortoises with mtDNA haplotypes closely related to another at-risk population (San Cristóbal) were also identified. These individuals could be considered as candidates for augmentation of natural populations or captive-breeding programmes and exemplify how molecular techniques can provide insights for the development of endangered species management plans.

Eastern collared lizards (Crotaphytus collaris collaris) on the Ozark Plateau of southern Missouri are restricted to islands of rocky glade habitat located throughout the oak-hickory forests of the region. Human mediated suppression of fire negatively impacts collared lizard populations by permitting the overgrowth and consequent disappearance of this glade habitat and also leads to a dense forest understorey that impedes movement of lizards between glades. We present data examining the effects of a fire management regime on collared lizard populations we monitored via mark/recapture from 1998 to 2001. We demonstrate increased glade-to-glade dispersal, colonization of previously unoccupied glades, and a significant increase in population size in the burned area. In addition, we show that populations within burned areas exhibit body sizes similar to those reported for populations living on healthy habitat as compared to those living on habitat that has deteriorated because of fire suppression. We conclude that managed forest fires positively impact collared lizard populations in the Ozarks, promoting factors that increase the long-term sustainability of the species.

Conservation practices are supposed to get refined by advancing scientific knowledge. We study this phenomenon in the context of monitoring tiger populations in India, by evaluating the ‘pugmark census method’ employed by wildlife managers for three decades. We use an analytical framework of modern animal population sampling to test the efficacy of the pugmark censuses using scientific data on tigers and our field observations. We identify three critical goals for monitoring tiger populations, in order of increasing sophistication: (1) distribution mapping, (2) tracking relative abundance, (3) estimation of absolute abundance. We demonstrate that the present census-based paradigm does not work because it ignores the first two simpler goals, and targets, but fails to achieve, the most difficult third goal. We point out the utility and ready availability of alternative monitoring paradigms that deal with the central problems of spatial sampling and observability. We propose an alternative sampling-based approach that can be tailored to meet practical needs of tiger monitoring at different levels of refinement.

Synthetic products based on biodiversity information such as gap analysis depend critically on accurate models of species' geographic distributions that simultaneously minimize error in both overprediction and omission. We compared current gap methodologies, as exemplified by the distributional models used in the Maine Gap Analysis project, with an alternative approach, the geographic projections of ecological niche models developed using the Genetic Algorithm for Rule-Set Prediction (GARP). Point-occurrence data were used to develop GARP models based on the same environmental data layers as were used in the gap project, and independent occurrence data used to test both methods. Gap models performed better in avoiding omission error, but GARP better avoided errors of overprediction. Advantages of the point-based approach, and strategies for its incorporation into current gap efforts are discussed.

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.

Specially trained detection dogs have been used to locate faeces (scats) for faecal analyses but their effectiveness has not been quantified. We evaluated detection and accuracy rates of dogs trained to find scats of endangered San Joaquin kit foxes (Vulpes macrotis mutica). Four dogs found from 0.43 to 5.37 presumptive kit fox scats per km of transect searched in two field sites where kit foxes and coyotes (Canis latrans) but not non-native red foxes (V. vulpes) were present. The unusually low detection rate (0.43 scats per km) by one dog (probably due to excessive panting in hot weather) was still similar to the average scat detection rate of two experienced humans. DNA tests of 1298 scats showed that all dogs were 100% accurate at distinguishing kit fox scats under our field conditions. Because red foxes are sympatric with kit foxes in some areas, we also conducted controlled discrimination experiments to see if trained dogs could distinguish between scats from kit and red foxes. Four dogs were 100% accurate at choosing a kit fox scat when red fox scats were present (n = 64 trials), but were less accurate at ignoring red fox scats in trials where a kit fox scat was absent.

Studies on the effects of nonindigenous invasive species and habitat fragmentation on native ecosystems have become priorities for conservation biologists. This is relevant particularly for islands with high degrees of endemism. In the present paper the role of fragmentation and possible effects of introduced Rattus rattus on endemic rodents (Macrotarsomys bastardi and Eliurus spp.) and the gray mouse lemur (Microcebus murinus) were assessed for dry deciduous forests in Madagascar. Capture rates of endemic rodents declined significantly with declining fragment size. Macrotarsomys bastardi was never caught in primary forest fragments < 600 ha or outside the primary forest but captures of M. bastardi were correlated to changes in vegetation structure associated with fragmentation rather than to fragment size per se. Eliurus spp. were also found in small primary-forest fragments and in secondary forests close to primary forests, suggesting that secondary forests can serve as buffer zones or corridors for this species. The lemur M. murinus was caught in all types of primary and secondary forest. This species did not seem to respond to fragmentation of primary forests. Even though it was found in most secondary-forests, capture rates declined as these secondary forest formations increased in size. This indicates that secondary forests are suboptimal habitats for M. murinus. Rattus rattus were caught in all vegetation formations except for the open savanna. Their capture rates increased as forest fragments became smaller, indicating that mosaics of different habitat types are beneficial for introduced rats. There was no significant relation between capture rates of R. rattus and the endemic species. In conclusion, these results suggest that (1) native Malagasy rodents of the dry deciduous forest are more sensitive towards forest disturbance than M. murinus; (2) there is no indication for negative interactions between introduced rats and the native small-mammal fauna.

Maritime ringlet butterflies (Coenonympha tullia nipisiquit McDunnough) are rare, endangered salt marsh butterflies with larvae that survive periodic tidal submergence. Only six disjunct populations are known to exist. First-instar larvae were released and monitored in seven microhabitats within a salt marsh in Bathurst, New Brunswick, Canada. From resighting data, microhabitat-specific daily death rates were estimated with maximum likelihood. The survival of the larvae released in groups was compared by calculating minimum number of larvae known to be alive (MNKA). Death rates were low in microhabitats with the larval host plant, salt meadow cordgrass (Spartina patens (Aiton) Muhl.) and the major nectar source, sea lavender (Limonium carolinianum (Walter) Britton), a habitat with a moderate frequency of flooding. Because microhabitats have a large effect on the survival rate of young larvae, use of microhabitat profiles in salt marshes as habitat-quality indices is recommended in critical-habitat assessment and reintroduction efforts.

It is becoming increasingly clear that species of smaller body size tend to be less vulnerable to contemporary extinction threats than larger species, but few studies have examined the mechanisms underlying this pattern. In this paper, data for the Australian terrestrial mammal fauna are used to ask whether higher reproductive output or smaller home ranges can explain the reduced extinction risk of smaller species. Extinct and endangered species do indeed have smaller litters and larger home ranges for their body size than expected under a null model. In multiple regressions, however, only litter size is a significant predictor of extinction risk once body size and phylogeny are controlled for. Larger litters contribute to fast population growth, and are probably part of the reason that smaller species are less extinction-prone. The effect of litter size varies between the mesic coastal regions and the arid interior of Australia, indicating that the environment a species inhabits mediates the effect of biology on extinction risk. These results suggest that predicting extinction risk from biological traits is likely to be a complex task which must consider explicitly interactions between biology and environment.

To achieve long-term viability of hunted puma (Puma concolor) populations (even at historically low densities), we propose a management plan based on the metapopulation concept that designates source areas (closed to hunting) and sink areas (open to hunting). We use 11 years of data from Idaho and Utah to demonstrate how the proposed management plan might be implemented. We use minimum and maximum densities of resident animals to calculate minimum and maximum effective population sizes, neighbourhood areas (regional management units) and usable habitat within the units. We designate sink and source areas based on their size, accessibility to hunters and juxtaposition. We show that closing 63% of puma habitat to hunting would ensure long-term puma population viability while permitting traditional hunting levels in other areas. This system could be adapted to existing state (and interstate) hunting management units, and we outline several steps by which wildlife agencies might set up a process (including public participation) to manage puma hunting.

Habitat loss and fragmentation are main causes for Asian elephant population declines. We mapped wildlands - large, unfragmented and undeveloped areas - asking: (1) Where are the largest wildlands that constitute elephant habitats? (2) What proportion of these wildlands is protected? (3) What is their potential for elephant conservation? Our study demonstrates that wildlands constitute only 51% of the Asian elephant range. Myanmar has the largest wildland (∼170,000 km2), followed by Thailand and India. In Principal Components Analysis (PCA), the first two components explained 73% of the variation in fragmentation among ranges. We identified three fragmentation clusters from the PCA. Cluster A contains large ranges with unfragmented wildlands; cluster B includes ranges with well-developed transportation networks and large human populations; and cluster C contains ranges with severely fragmented wildlands. In cluster A, we identified four ranges with elephant populations >1000 animals: ARYO, MYUC, BNMH and BITE. Together with ranges that support >1000 elephants in cluster B, these A ranges have great potential for long-term elephant conservation. We propose that fragmentation clusters and population size can be used to identify different elephant monitoring and management zones.

The wild water buffalo is highly endangered, with the few remaining populations already affected or likely to be increasingly affected by hybridization with domestic buffalo. The work described here was done to evaluate a genetic method to discriminate wild from mixed ancestry (hybrid) and domestic animals, and to identify with high probability those most likely to be purebred wild. Samples from 45 animals (phenotypically classified into three groups - ten wild, 28 domestic and seven hybrid) were genotyped for ten microsatellite loci. Although genetic distances among the three groups were small, an assignment test identified two of the ‘wild’ and seven of the ‘domestic’ as hybrids. However, sample sizes also are small, indicating the need for a conservative approach in the first instance in using these results. As more animals are genotyped, assignments will become more accurate, and a translocation programme to establish a second Nepalese wild population in a protected area could be undertaken.

Changes in abundance and the risk of extinction of the rock partridge Alectoris graeca saxatilis in the Dolomitic Alps were investigated using a density-dependent model that incorporated dispersal and environmental stochasticity. The study was based on spring and summer counts collected from sample areas in geographically distinct mountain groups. Extinction probability was investigated by simulating a discrete population and a metapopulation consisting of local populations connected by dispersal. Persistence was not guaranteed when the species was examined as a discrete population. When we used a metapopulation approach, the persistence was assured but local extinctions with subsequent recolonizations of a number of empty areas were observed. The analysis was repeated using hunting statistics, when there were no restrictions on hunting policies, and a similar high extinction pattern was found. Our simulations suggested that long-term persistence of rock partridge could be guaranteed only when immigration was included into the demographic model. However, if the increased population's fragmentation recorded since the 1950s persists the extinction of some of the subpopulations appears inevitable.

Habitat loss and alteration is the leading cause of species' declines world-wide, therefore habitat restoration and protection is a prominent conservation strategy. Despite obvious connections between habitat and threatened or endangered species, conservationists have been hard pressed explicitly to link abundance or population health with habitat attributes. Given that habitat relationships with species are often characterized at a spatial scale that does not account for the functional relationships between habitat and populations, it is not surprising that the habitat-population conundrum persists. In order to explore the influence of spatial scale on the apparent relationship between habitat and populations, we examined the relationship between GIS-based habitat data and spring/summer chinook salmon (Oncorhynchus tshawytscha) redd (spawning nests built by females) densities in the Salmon River basin, Idaho, at two very different spatial scales: stream reach and watershed. Redd density was strongly correlated with climate, geology, wetlands and terrain. However, our stream-reach scale models provided poor predictive power compared with the watershed scale models. Based on these results, we conclude that our perception of which habitat attributes were important was clearly a function of our scale of observation, and that restoration efforts should focus on conditions at the watershed or landscape scale when attempting to do local or reach scale restoration projects.

The Przewalski's gazelle (Procapra przewalskii) is critically endangered and has experienced significant decline in population numbers in the past, and now survives in four isolated populations: the Bird Island, Hudong-Ketu, Yuanzhe and Shadao-Gahai populations. To understand better the effect of habitat fragmentation and geographical isolation on gene flow and genetic variation, and uncover genetic units for conservation, we examined the hypervariable region (420 bp) of the mitochondrial DNA control region of 29 Przewalski's gazelles from four localities distributed throughout their present geographical range. Phylogenetic analysis consistently revealed four distinct mtDNA lineages within Przewalski's gazelle, with each lineage restricted to a single geographical location. The study revealed a marked divergence of lineages from the Bird Island population relative to other populations, which corresponds to the geographical association. The nucleotide diversity within populations was very low (less than 0.004). The value of Nm was less than 0.3 individuals per generation, indicating low gene flow between populations. It was suggested that the Yuanzhe, Hudong-Ketu and Shadao-Gahai populations be managed as a conservation unit because of their genetic and geographical closeness.

Umbrella species are ‘species with large area requirements, which if given sufficient protected habitat area, will bring many other species under protection’. Historically, umbrella species were employed to delineate specific reserve boundaries but are now used in two senses: (1) as aids to identifying areas of species richness at a large geographic scale; (2) as a means of encompassing populations of co-occuring species at a local scale. In the second sense, there is a dilemma as to whether to maximize the number or viability of background populations; the umbrella population itself needs to be viable as well. Determining population viability is sufficiently onerous that it could damage the use of umbrella species as a conservation shortcut. The effectiveness of using the umbrella-species concept at a local scale was investigated in the real world by examining reserves in East Africa that were gazetted some 50 years ago using large mammals as umbrella species. Populations of these species are still numerous in most protected areas although a few have declined. Populations of other, background species have in general been well protected inside reserves; for those populations that have declined, the causes are unlikely to have been averted if reserves had been set up using other conservation tools. Outside one reserve, Katavi National Park in Tanzania, background populations of edible ungulates and small carnivores are lower than inside the reserve but small rodent and insectivore abundance is higher. While we cannot compare East African reserves to others not gazetted using umbrella species, the historical record in this region suggests that umbrella species have been an effective conservation shortcut perhaps because most reserves were initially large and could encompass substantial populations of background species. It is therefore premature to discard the local-scale umbrella-species concept despite its conceptual difficulties.