Animal Conservation

Published by Wiley
Online ISSN: 1469-1795
Members of the order Psittaciformes (parrots and cockatoos) are among the most long-lived and endangered avian species. Comprehensive data on lifespan and breeding are critical to setting conservation priorities, parameterizing population viability models, and managing captive and wild populations. To meet these needs, we analyzed 83, 212 life history records of captive birds from the International Species Information System and calculated lifespan and breeding parameters for 260 species of parrots (71% of extant species). Species varied widely in lifespan, with larger species generally living longer than smaller ones. The highest maximum lifespan recorded was 92 years in Cacatua moluccensis, but only 11 other species had a maximum lifespan over 50 years. Our data indicate that while some captive individuals are capable of reaching extraordinary ages, median lifespans are generally shorter than widely assumed, albeit with some increase seen in birds presently held in zoos. Species that lived longer and bred later in life tended to be more threatened according to IUCN classifications. We documented several individuals of multiple species that were able to breed for more than two decades, but the majority of clades examined had much shorter active reproduction periods. Post-breeding periods were surprisingly long and in many cases surpassed the duration of active breeding. Our results demonstrate the value of the ISIS database to estimate life history data for an at-risk taxon that is difficult to study in the wild, and provide life history data that is crucial for predictive modeling of future species endangerment and proactively managing captive populations of parrots.
A simple model was developed to estimate seabird mortality across the fishery. Total fishing effort was estimated to be 60 000 trawls per year, based on 79 vessels fishing for 70% of the year and making on average three trawls per day (B. Rose, pers. comm.). Most trawls are conducted during daylight due to the vertical migration of hake. The first tow of the day thus seldom results in seabird interactions with the warp because no offal is discharged; these tows were excluded from warp interactions. Also excluded were four vessels with macerators (devices to finely chop discards, making them less attractive especially to large birds) as well as vessels that retain wastes to make fish meal, either on board (four freezer vessels) or returning it to land (eight wet fish boats on the last 3 days of their trips). This resulted in a total of c. 35 000 trawls with dumping taking place. Due to longer days in summer, effort was weighted 55% to summer trawls. Dumping was assumed to average 1 h per trawl, with total trawl duration averaging 3 h. These estimates are conservative; utilization of vessels averages above 70%, some dumping takes place from vessels with fish meal plants and macerators, and dumping lasted 1.2 h on average during our study trips. The effort data were used to calculate the total amount of time spent trawling in winter and summer both while dumping and not dumping, and this was used to extrapolate total mortality from the observed estimates of warp mortality. Mortality of birds entangled in nets can happen on any trawl, because it results from birds attempting to steal fish from the net. It is independent of dumping activity, and thus all trawl effort was included in the extrapolation of this mortality.
Catfishes of the family Pangasiidae are an important group that contributes significantly to the fisheries of the Mekong River basin. In recent times the populations of several catfish species have declined, thought to be due to overfishing and habitat changes brought about by anthropogenic influences. The Mekong giant catfish Pangasianodon gigas Chevey, 1913 is listed as Critically Endangered on the IUCN Red List. In the present study, we assessed the level of genetic diversity of nine catfish species using sequences of the large subunit of mitochondrial DNA (16S rRNA). Approximately 570 base pairs (bp) were sequenced from 672 individuals of nine species. In all species studied, haplotype diversity and nucleotide diversity ranged from 0.118±0.101 to 0.667±0.141 and from 0.0002±0.0003 to 0.0016±0.0013, respectively. Four haplotypes were detected among 16 samples from natural populations of the critically endangered Mekong giant catfish. The results, in spite of the limited sample size for some species investigated, indicated that the level of genetic variation observed in wild populations of the Mekong giant catfish (haplotype diversity=0.350±0.148, nucleotide diversity=0.0009±0.0008) is commensurate with that of some other related species. This finding indicates that (1) wild populations of the Mekong giant catfish might be more robust than currently thought or (2) present wild populations of this species carry a genetic signature of the historically larger population(s). Findings from this study also have important implications for conservation of the Mekong giant catfish, especially in designing and implementing artificial breeding programme for restocking purposes.
In view of their ecological importance and the abundance of threats on a developing Caribbean island, we surveyed the bats of Curaçao, Netherlands Antilles, and examined changes in the populations of seven threatened species over a decade, using previously published data as a baseline for comparison. The most important caves for bats (in terms of species representation and reproduction) were visited yearly, and monthly in 2001. Noctilio leporinus still occurs on the island, but does not appear to be numerous (six observed in 2003). We captured Myotis nesopolus nesopolus, but its roosting sites remain unknown. Leptonycteris curasoae curasoae numbers varied greatly, even within a year, and it may travel to and from other islands and Venezuela. Overall, however, the population of this species on Curaçao seems to be declining (1000 in 1993 and 625 in 2003); the disappearance of this pollinator could have severe consequences for the Curaçao ecosystem. Mormoops megalophylla intermedia is declining as well; in 2003, we counted 403 individuals including 75 pups, from 500 to 600 adults in the 10 previous years, representing a 25–30% decline in 1 year. We estimated the population of Natalus tumidirostris to be 890 in 2003. We also found a group of 60 Pteronotus davyi in Kueba di Ratón in 2003. Glossophaga longirostris elongata (1417 individuals counted) is the only species for which our data indicate relative stability over 10 years; L. curasoae and Mor. megalophylla are declining and other species must be monitored closely. Most caves are disturbed; four major caves require attention for the conservation of the most fragile species. Without immediate attention, Mor. megalophylla, in particular, risks imminent extinction. Despite problems associated with bat counts on Curaçao, it is clear that regular surveys are crucial to understand bat populations and their fluctuations in caves, and to allow management responses to declines, particularly for areas undergoing rapid urbanization.
In recent years, population viability analysis has become a popular tool to assess the relative risk of extinction among populations. Viability estimates for spatially structured populations require movement data that are often unavailable. In this paper, a diffusion approximation model was used to explore the effects of different spatial scenarios resulting from assumptions about movement rates. Census data for 13 breeding islands occupied by California sea lions Zalophus californianus californianus in the Gulf of California were used to explore three potential scenarios: unlimited movement between sites (panmictic population), limited movement (several clusters of populations) and no movement between islands (isolated islands). Predicted viability estimates were different for each scenario, but contrary to expectations, the mean extinction risk estimates were generally lowest when movement was unlimited (panmictic scenario). However, despite an extensive dataset, the confidence of the viability predictions for each scenario was low. In some cases, uncertainty in predictions within a scenario was greater than differences between scenarios. Therefore, it is recommended that in situations where movement rates and spatial structure are unknown, extinction risk estimates should reflect both the confidence intervals for each risk estimate and the uncertainty resulting from different spatial scenarios. This study also provides the first estimate of population viability (considering spatial structure) for California sea lions in the Gulf of California and an evaluation of population status based on the IUCN criteria for species listing.
The claim that the Florida panther Puma concolor coryi has been genetically rescued by the introduction of Texas cougars P. c. stanleyana is based on the questionable development and interpretation of a maximum likelihood model, data dredging and a misleading presentation of historical data. In addition, the claim that Florida panther ‘hybrids are expanding the known range of habitats panthers occupy and use’ is offered in the absence of data or supporting analyses. By (1) ignoring regional differences in habitat quality, (2) ignoring the earlier extinction of the hybrid Everglades population, (3) ignoring the influence of social structure on the relative success of Texas cougars and their offspring, (4) using cursory spatial analyses of panthers before and after intervention and (5) choosing a second-best model, a misleading scenario was presented. Undoubtedly hybrid animals have increased in abundance and distribution on the south Florida landscape, but it is quite possible that current patterns of abundance and distribution would be similar if purebred Florida panthers had been introduced instead of Texas cougars in 1995. This is because all the demographic events that have occurred since genetic intervention in 1995 can be more reasonably explained by factors relating to panther social structure and habitat variability. We are hopeful that the current genetic management effort will contribute to the recovery of this endangered population; however, it is too early to claim that this intervention has succeeded or failed. We suggest a number of ways in which more reliable insight on this issue might be obtained.
Hamer et al. (2008) results suggest that the CoP is highly effective, albeit their assessment covered only a 7-month period. Although we welcome the implementation of the CoP, we counsel caution about confidence in its efficacy. CoPs are not universally effective and may lead to a false sense that the problem has been resolved (Wiley et al., 2008). To the best of our knowledge, the most successful bycatch mitigation program was based upon an extensive, ongoing 100% observer coverage, application of proven mitigation measures, annual expert review and evolving fishery and mitigation practices (Waugh et al., 2008). The observer coverage reported in Hamer et al. (2008) was 11.8% and the assessment time (7 months) was short. We emphasize the importance of a careful and independent long-term monitoring of the efficacy of the industry CoP. The CoP is at its early stages of implementation, and using the ‘worst case bycatch statistics’ in the absence of a long-term, extensive observer programs is a precautionary approach.
Refuge populations of Cyprinodon macularius and Cyprinodon eremus, the extant members of the endangered desert pupfish complex, have been maintained for up to 33 years in semi-natural refuges. We examined the success of the refuge program in maintaining diversity at four microsatellite DNA loci in 24 refuge populations of C. macularius and six of C. eremus that include, respectively, seven and four lineages representing original translocations from the wild. These lineages have been maintained with essentially no inoculations of genetic material from the wild and, except for one refuge, no intermixing of lineages. Comparison with wild-source populations showed marked declines in diversity within local refuges and within lineages, but relatively minor declines for the composite of all refuge populations for each species. In genetic makeup, the refuge populations generally clustered by lineage, indicating significant genetic drift early in lineage history. The results indicate that, with relatively minor adjustments in management, the refuge program can successfully preserve a large portion of the wild genetic diversity in the desert pupfish complex.
Koalas have undergone a series of sequential founding events on islands in south-eastern Australia in recent times. Populations in South Australia at the Eyre Peninsula and Mt Lofty Ranges were founded in the 1960s from a colony on Kangaroo Island. The Kangaroo Is. colony was derived from animals introduced to French Island from mainland Victoria over a century ago. In this study, we first use microsatellite markers to quantify levels of genetic variation within the South Australian koala populations and the relatively unperturbed Strzelecki Ranges population from mainland Victoria. This analysis revealed low levels of allelic diversity (1.7 ± 0.2 to 2.7 ± 0.5) and heterozygosity (0.208 ± 0.088 to 0.340 ± 0.110) in the three South Australian koala populations relative to the Strzelecki Ranges population, which has the highest levels of allelic diversity (4.7 ± 1.1) and heterozygosity (0.476 ± 0.122) in Victoria. Second, we measured the incidence of testicular aplasia, a unilateral or bilateral failure in testicular development, in the Eyre Peninsula and Kangaroo Is. populations, and in the ultimate founding population at French Is. Testicular aplasia was present at a frequency of 4.3% in French Is., 12.8% in Kangaroo Is. and 23.9% in the Eyre Peninsula, but was undetectable in the non-bottlenecked Pilliga State Forest population of New South Wales. The incidence of testicular aplasia correlated positively with effective inbreeding coefficients derived from heterozygosity values (0.13 ± 0.06 in the Pilliga State Forest, 0.57 ± 0.17 in French Is., 0.63 ± 0.12 on Kangaroo Is. and 0.77 ± 0.12 in the Eyre Peninsula), which may indicate inbreeding depression. These findings are of concern when evaluating the long-term conservation and viability of the South Australian koala populations, which may benefit from genetic augmentation in the future. Finally, unconfirmed reports suggested that animals from other states in Australia were introduced into the Mt Lofty Ranges population. Therefore, we quantified differentiation between the three South Australian populations and the Strzelecki Ranges and French Is. populations, based on microsatellites and mtDNA d-loop region variation. R-statistics and Goldstein's delta mu square distance revealed that differentiation at nuclear loci between populations paralleled known recent population history, except for the close relationship between Mt Lofty Ranges and French Is. This suggested a recent contribution to the Mt Lofty Ranges populations of animals derived from the French Is. translocation program. Furthermore, mtDNA d-loop analysis found no evidence of contributions to the gene pool from animals of New South Wales or Queensland stock, implying that the population was derived exclusively from Victorian stock.
A schematic diagram comparing the two habitat sampling regimes used. The current habitat method (episode 2, n=229) consists of eight regularly spaced sample points (closed circles). The habitat change method (episodes 1 and 2, n=53) consists of a series of transect points (open circles) different distances from the ditch edge. The dashed arrow represents the route used to measure vegetation height for the habitat change analysis (Table 2).
The variation between episodes (filled circles, episode 1 – 1990/1991/1992; open circles, episode 2 – 2006) and visits (1–3) in (a) soil penetration resistance (kgf), (b) soil moisture content from soil cores [ratio of soil water (g)−dry soil (g)] and (c) soil moisture content (% by volume) from theta probe measurements for all regions (ordered by population trend from declining; Avon, Broads, Arun and Scottish Farmland to stable or increasing; Somerset, Derwent, Insh and Nene). See Table 5 for ANOVA results. All data are means±95% CI. In (a) the line drawn at 5.8 kgf and data from 1983 for the Nene Washes and Somerset (open triangles) is taken from Green (1988) to allow comparison with this earlier study.
Results of general linear models of two aspects of habitat change, soil moisture content and penetration resistance
Results of general linear mixed models of the effects of land management on the aspects of habitat, which are important correlates of snipe Gallinago gallinago population change
The results of paired comparisons (Wilcoxon's signed-rank tests) of the habitat management factors that are important in influencing soil penetration resistance and soil moisture
Snipe Gallinago gallinago breeding on lowland wet grasslands in England have undergone widespread and dramatic declines in abundance and distribution since at least the 1970s. There are many potential drivers of the decline but reductions in habitat quality, driven by land management, are often proposed as a contributing factor in the historical declines of breeding waders. Breeding snipe are now restricted to a few key places such as nature reserves and environmentally sensitive areas where management for breeding waders is implemented. On average, populations have continued to decline, even in these key areas, though population trends vary from a decline of 98% to an increase of 61% between the early 1990s and 2006. We examined the relationship between regional variation in snipe population trends and soil conditions, other habitat features and land management. Snipe were more likely to persist in fields where the soil conditions were wet and soft. Fields are wetter and softer now than in the early 1990s and management influenced these conditions. Soil softness increased with decreasing grazing pressure and increasing surface flooding. Soil moisture increased with surface flooding and was higher in organic soils. Changes in field condition were consistent with decreases in grazing pressure and increases in surface flooding. In spite of habitat condition being altered in a way that should have been beneficial to snipe, the numbers have continued to decline. Thus, it is unlikely that the measures of habitat condition examined here have been the driver of the decline and other factors must be involved. Research efforts should now focus on alternative explanations of the decline, for example, changes in other key aspects of habitat quality such as prey abundance, or changes in snipe productivity or mortality.
Location of the Agua Blanca State Park in south-eastern Mexico and the sites for bat sampling in each vegetation patch.
Fitted accumulation curves for the bat species inhabiting four vegetation successional stages (TEF, tropical evergreen forest; OSF, old growth secondary forest; MSF, middle-aged secondary growth forest; YSF, young secondary forest) in the Agua Blanca State Park, Tabasco, Mexico.
Total bat richness, diversity and abundance in four secondary successional stages of tropical evergreen forest in the Agua Blanca State Park, Tabasco, Mexico
Vegetation had a significant effect on the mean abundance across rainy seasons (±se) for the six most abundant bat species of the Agua Blanca landscape. YSF, young secondary growth forest; MSF, middle-aged secondary growth forest; OSF, old secondary growth forest; TEF, tropical evergreen forest. Columns marked with different letters were significantly different.
of a repeated measure MANOVA to assess the effect of successional stage, season and their interaction on the correlated response variables richness, evenness (diversity) and total abundance
Under the hypothesis that bat diversity would be lower in the early stages of secondary succession and that species affected negatively by habitat modification would be more frequent in later successional stages, we evaluated how bats use 12 vegetation stands representing four stages of secondary succession, following disturbance caused by slash-and-burn agriculture and selective logging. We compared bat richness, abundance and diversity, and found that none of these variables was different among stages or rainy seasons. However, of the 10 most common bat species, two were significantly more abundant in stands at the early stages of secondary succession, while the opposite was true for three other species. Canopy cover mainly explains these patterns. Rainy season had no effect on the abundance of the common species. The results of this study indicate that although some frugivorous species were very abundant in the younger stands, the majority of the rare species were captured in older stands. The absence of rare and habitat-specialized species from young successional stages close to primary forest suggests that, for effective bat conservation in landscapes modified by human activity, areas with original vegetation should be maintained to ensure the survivorship of sensitive-to-deforestation species.
Approximate midpoints of routes in our Coto Brus study area. The routes are shown over a Landsat image. The darkest areas are old second growth/mature forest, for example in the upper right corner of the image, where the Talamanca Mountains and Las Tablas Protected Zone are located, and in the lower left of the image, where the Coastal Range is located. Shades of gray in the central part of the image are pasture, agriculture, residential areas and roads.
Response variables and the explanatory variables in poten- tial models
Numbers of species detected in both study areas or in only one of the study areas
Selected regression models, based on AIC c values
Predicting the consequences of land-cover change on tropical biotas is a pressing task. However, testing the applicability of models developed with data from one region to another region has rarely been done. Bird faunas were sampled along 3.0-km routes in southern Costa Rica (Coto Brus) to develop statistical models to describe the abundance and richness of groups as a function of land-cover characteristics. The relative value of the land-cover models was assessed by comparing them with null models. The generalizability of the models was tested with data from north-western Costa Rica (Monteverde) to determine whether the models were applicable to another area that has undergone significant land-cover change in the last 60 years. The richness and abundance of understory, open-country and edge non-insectivore groups showed clear relationships with land-cover variables, and the land-cover models had lower prediction errors than the null models for Coto Brus. With one exception, useful models for canopy birds, edge insectivores and hummingbirds could not be developed. The land-cover models of abundance of canopy insectivores, understory insectivores and non-insectivores, and edge non-insectivores were generalizable to Monteverde whereas the land-cover models of abundance of open-country birds and species richness for any of the groups were not better than null models for Monteverde. The results indicate that land-cover models that describe the abundance or richness of various bird groups provide useful predictions in the area where the data were collected and that models of abundance of some canopy, understory and edge birds may perform well in areas that are similar in elevation, life zones and land use to the area from which data were collected. Land-cover models of the abundance of other groups, and of the richness of the majority of groups, may be less generalizable to other areas, or it may be difficult to develop models at all.
Amphibians are currently experiencing a severe worldwide decline. Several factors, such as habitat alteration, climate change, emerging diseases or the introduction of exotic species, have been signalled as being responsible for the reduction of amphibian populations. Among these, the introduction of fish predators has been repeatedly indicated as a factor affecting the distribution of many species. The present study was developed to examine the effect of fish presence and other environmental factors on the distribution and abundance of amphibian species in mountain lakes of the Cantabrian Range in northern Spain. We found no effect of salmonid presence on the distribution and abundance of two widespread anuran species Bufo bufo and Alytes obstetricans, whereas Rana temporaria showed a non-significant tendency to be absent from salmonid-occupied lakes. However, the presence of introduced salmonids was the main negative factor explaining the distribution of the newt species Triturus helveticus, Triturus alpestris and Triturus marmoratus. The effect on these species is likely to be due to increased larval mortality, as adult and egg predation by fish, or oviposition avoidance by female newts has rarely been recorded. Fish removal and the creation of alternative breeding habitats for amphibians are proposed as conservation measures to recover amphibian populations in the vicinity of fish-stocked lakes.
Variation at both the patch and landscape scale is known to influence the distribution and abundance of arboreal monkeys in rainforest fragments. However, few studies have examined the factors associated with these different scales of focus simultaneously. Using stepwise logistic-regression and generalized linear models (GLMs), howler monkey Alouatta palliata distribution and abundance were examined as a function of patch quality (fragment area, shape, tree DBH and canopy height) and landscape connectivity (isolation, total forest area, fragment and road abundance, corridor abundance and length) in 119 rainforest fragments in northern Chiapas, Mexico. The positive correlation observed between monkey distribution (presence/absence) and both fragment area and abundance may be explained by increased resources within larger fragments and those whose proximity allows greater exploration by monkeys. In contrast, GLM analysis indicated that monkey abundance in inhabited fragments was positively correlated with corridor abundance, canopy height and fragment area. These relationships could be explained by greater reproductive investments by monkeys in forest fragments whose size, degree of perturbation and degree of connectivity with other fragments suggest greater overall resource availability. Future studies should explicitly include a multi-scale approach to understanding the factors affecting patterns of monkey distribution and abundance, particularly as this relates to measures of and interactions between patch connectivity and resource availability.
Results from mixed models (for normally distributed data) testing for changes of slope in herbivore populations
Trends in the total number of elephants counted at waterholes in the northern part of Hwange National Park. The line represents the changes in the 3-year running means (mean of years n−1, n and n+1). The vertical dotted lines separate the three study periods (see text for details).
In some African protected areas, elephant populations have reached high densities causing concern about their influence on other forms of biodiversity, and in particular, other large herbivores. This has led to a debate whether management of elephant populations might need to be implemented. Surprisingly, few studies have focused on the influence of elephants on other herbivores and the existing results are conflicting. We investigated such influence in Hwange National Park, Zimbabwe, where elephants were culled and maintained at low density up to 1986, and have more than doubled since then, thus providing the opportunity to explore their possible influence on other herbivore species. Trends of different herbivore populations were obtained using long-term waterhole census data, with these results also being correlated to changes in dry season rainfall, as another fundamental determinant of herbivore population fluctuations. While our study did not allow us to properly disentangle the role of elephants and rainfall, it provided valuable insights. For five out of the 13 herbivore species studied, the population increased between 1973 and 1986 (high dry season rainfall; relatively low elephant abundance), then decreased between 1987 and 1995 (extremely low dry season rainfall; increase in the elephant population), and finally have increased since 1996 (high dry season rainfall; high elephant abundance). These results are consistent with an important role of dry season rainfall on herbivore population dynamics. Additionally, for four other species, the population increased between 1973 and 1986 and has decreased since then. As most herbivore declines occurred simultaneously with increase in the elephant population in the 1987–1995 period, and with the recent increase in most populations happening at a lower rate than the 1973–1985 period, our results suggest the possible existence of a negative influence of high elephant densities on other herbivores. We discuss what the possible underlying mechanisms can be and how to investigate them.
Locations of the two study sites, (a) Hoshui-Chinsha Stream and (b) Chienpu Stream in Kinmen. Letters on the maps represent artificial features, such as bridges, which were landmarks used as reference points for recording the locations of the spraints collected during the study.  
Relationship between the theoretical, observed and sib probability of identity, P (ID) , and the number of microsatellite loci in a sample of 38 Kinmen Eurasian otters. Loci on the x-axis are arranged from the highest to the lowest expected heterozygosity. The horizontal line identifies a P (ID) of 0.01. * indicates the P (ID)sib value (8.01×10 −3 ); † indicates the observed P (ID) value (5.69×10 −3 ) using seven loci.  
Numbers of residents (filled bars) and floaters (grey bars) occurring in different seasons during 2001 along (a) Hoshui- Chinsha Stream and (b) Chienpu Stream. Samples of Chinsha Stream were only collected in August and November 2001. * indicates two floaters; † indicates one floater that occurred only in Chinsha Stream and not in Hoshui Stream.  
UPGMA clustering of pair-wise genetic distances between otters sampled in Chienpu and Hoshui-Chinsha Streams. , residents of Chienpu Stream; , residents of Hoshui-Chinsha Stream. The vertical lines on the right indicate that the division of groups corresponded to their geographical locations.
In this study, non-invasive molecular methods were used to investigate the abundance and spatial organisation of otters (Lutra lutra) in Kinmen. DNA samples were extracted from fresh spraints collected seasonally along two streams from February to November 2001 and genotyped using a panel of 7 microsatellites and the SRY gene. Out of 343 spraints, 222 were successfully genotyped and 38 different genotypes (19 females and 19 males) were identified. Thirteen of these were residents that were identified in more than one season and 25 were floaters that were only identified in a single season. The average number of otters per km found along the two streams (1.5–1.8 for all otters, or 0.8–1.1 for residents only) was higher than that estimated in other studies. Female residents lived in exclusive group ranges and the ranges of male residents overlapped with no more than one group range of female residents. Otters appearing in the same range tended to be more closely related to each other. This study demonstrates that non-invasive molecular methods can be used to reveal a more comprehensive estimation of size and structure in an otter population.
Few studies link habitat to grizzly bear Ursus arctos abundance and these have not accounted for the variation in detection or spatial autocorrelation. We collected and genotyped bear hair in and around Glacier National Park in northwestern Montana during the summer of 2000. We developed a hierarchical Markov chain Monte Carlo model that extends the existing occupancy and count models by accounting for (1) spatially explicit variables that we hypothesized might influence abundance; (2) separate sub-models of detection probability for two distinct sampling methods (hair traps and rub trees) targeting different segments of the population; (3) covariates to explain variation in each sub-model of detection; (4) a conditional autoregressive term to account for spatial autocorrelation; (5) weights to identify most important variables. Road density and per cent mesic habitat best explained variation in female grizzly bear abundance; spatial autocorrelation was not supported. More female bears were predicted in places with lower road density and with more mesic habitat. Detection rates of females increased with rub tree sampling effort. Road density best explained variation in male grizzly bear abundance and spatial autocorrelation was supported. More male bears were predicted in areas of low road density. Detection rates of males increased with rub tree and hair trap sampling effort and decreased over the sampling period. We provide a new method to (1) incorporate multiple detection methods into hierarchical models of abundance; (2) determine whether spatial autocorrelation should be included in final models. Our results suggest that the influence of landscape variables is consistent between habitat selection and abundance in this system.
Droughts induced by the 1997–1998 El Niño Southern Oscillation (ENSO) event sparked large-scale forest fires affecting millions of hectares on Borneo. We studied the effects of ENSO-induced disturbances on a riverine bird, the critically endangered white-shouldered ibis, Pseudibis davisoni, along the Mahakam River in East Kalimantan, Indonesian Borneo. Island-wide fire hotspots were more likely to occur near rivers and part of our study area was indeed affected by fire. Based on 25 boat surveys (2590 km) that yielded 91 records, we recorded significant changes in abundance and spatial distribution of this bird in our study area. Encounter rates were higher during the pre-ENSO (1992–1996) periods than the post-ENSO (1997–2000) ones and differed between seasons. No ibises were seen post-ENSO along river sections that were affected by the fires, whereas pre-ENSO encounter rates were 2.4 birds/102 km. Encounter rates along those sections that were not affected by the forest fires more than doubled from 2.0 birds/102 km pre-ENSO to 5.6 birds/102 km post-ENSO. This was most probably due to enhancement of displaced birds. In view of the permanent character of the change in spatial distribution, active protection of the remaining stretches of riverine forest is of the utmost importance for the survival of white-shouldered ibis.
Breakdown of threat levels and the IUCN criteria used for the family Accipitridae
Explanatory variables and their description
Cross taxa analysis without phylogenetic correction, showing the slope of an ordinal response model for the analysis of IUCN threat status and non-parametric correlations for the other analyses
Multiple regression models examining predictors of independent contrasts in IUCN threat status, population size and range size for Accipitridae (n = 171)
One of the most important tasks in conservation biology is identifying species at risk from extinction and establishing the most likely factors influencing this risk. Here, we consider an ecologically well-defined, monophyletic group of organisms, the true hawks of the family Accipitridae, which are not only among the most studied, but also contain some of the rarest bird species in the world. We investigate which intrinsic and extrinsic factors, covering morphology, life history and ecology, covary with International Union for the Conservation of Nature and Natural Resources threat status, as well as global population size and geographic range size. By decomposing threat status into population size and range size, we test whether any factors are generally important: we found that species with less habitat specialization, a larger clutch size and more plumage polymorphism were associated with lower extinction risk and larger population and range sizes. Species with special habitat requirements might be less capable of dealing with habitat transformation and fragmentation, while species with small clutch sizes might not be able to reverse population declines. Plumage polymorphism might indicate the size of the species' gene pool and could be a good marker of extinction risk. The analyses also emphasized that no single factor is likely to be sufficient when predicting the threat of extinction.
Fecal glucocorticoid metabolite (FGM) analysis provides a non-invasive method for studying the physiological response of wildlife to a variety of stressors and is a ground-breaking monitoring technique in wildlife management and conservation. The conservation benefits of successful wildlife translocation restocking efforts are significant but understandably stressful for the animals being captured, removed from familiar habitat, held in captivity in many cases and subsequently released into an unfamiliar environment. It is imperative that we identify non-invasive methods for evaluating stress in translocated animals, especially in endangered species. Twenty Grevy's zebra Equus grevyi were translocated to Meru National Park as part of a Kenya Wildlife Service re-population initiative. FGMs were monitored from the time of capture, during captivity and post-release as an indicator of the stress of translocation and acclimation to the new environment. FGMs from representative non-translocated zebra were used as a further control. When held in pens at Meru Park 3–4 and 5–6 weeks after capture, the zebra had higher FGMs (25.1±1.2 and 23.4±1.3 ng g−1) than either at the time of capture (14.6±2.1 ng g−1) or non-translocated controls (16.2±1.2 ng g−1). This suggests that the stress of captivity elevated FGMs. FGM concentrations returned to pre-capture concentrations c. 11–18 weeks after the zebra were released into Meru Park. The return of FGM concentrations to baseline suggests successful acclimation to the new environment. This study supports the use of FGM analysis as an assessment technique in wildlife management projects involving the movement of endangered large mammals with application for monitoring stress in a wide array of conservation projects involving translocation, reintroduction and rehabilitation.
Concentrations of adrenal steroid metabolites in feces are routinely used to assess the welfare of animals that are the subject of conservation efforts. The assumption that low and declining corticoid concentrations indicate the absence of stress and acclimation, respectively, is often made without experimental support or wild-animal comparisons, although intrinsic control of adrenal steroids might occur even under ongoing stress and distress. We adopted the capture and 11-week captivity of 18 black (Diceros bicornis: 11 males, seven females) and 52 white (Ceratotherium simum: 22 males, 30 females) rhinoceros as an experimental test of the relationship between corticoid concentrations and stress (translocation) and measured for suppressed gonad function as an indicator of distress – the biological cost of cumulative stressors. Fecal samples collected from the rectum at capture and during captivity were stored frozen and their corticoid, and androgen (in males) or progestin (in females), concentrations determined by radioimmunoassay. Corticoid profiles followed the expected pattern of being two to five times pre-capture levels (ng g−1: black rhino: female 24.5±3.7, male 23.9±2.2; white rhino: female 16.3±1.6, male 12.3±2.4) for up to 17 days after capture and declined with time in captivity. Black rhinoceros and male white rhinoceros corticoids declined below pre-capture values and were associated with suppressed levels of androgens and progestins with increased time in captivity. Declining corticoids could not be interpreted as acclimation or the absence of stressors, without also measuring for distress in African rhinoceros. White rhinoceros female corticoid values remained elevated, although their gonad steroid levels were also suppressed. We discuss our findings for the management of rhinoceros in the wild and captivity.
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.
Cumulative percentage of carcasses that had disappeared on the different survey dates (=day after carcasses were placed under the power line). Means and standard deviations are given.
Results of the generalized linear model for carcass detect- ability
Detection ability of the four observers participating in the detectability trial (black dots), as a function of their experience (defined as the number of kilometres of power line surveyed before the present study). The curve represents the equation adjusted to the four detection ability values: y=24.461+13.827 × log10 (x) (r=0.961, P<0.04).
of the generalized linear model for carcass disap- pearance on the last survey date (day 28 after placing carcasses)
Bird mortality as a result of collisions with power lines has been of increasing concern in recent decades, but the real impact on bird populations requires an experimental assessment of scavenger removal rates and searcher detection errors. Farmland and steppe birds, two of the most threatened avian groups, have been shown to be particularly vulnerable to collision with power lines, but few removal and detectability studies have been developed in cereal farmland habitats, and none in the Mediterranean region. We conducted five carcass disappearance trials in central Spain by placing 522 corpses of different sizes under power lines, and searching for remains four times during the following month. The influence of several factors was examined using multivariate approach. The accumulated number of carcasses removed by scavengers increased logarithmically, with 32% removed over the 2-day period after the initial placement, but only 1.5% removed on a daily basis by day 28. Small birds disappeared earlier and at a higher proportion than larger birds. Carcass removal rates were site-dependent, but were not influenced by carcass density or season. The detection rate increased with the observer's previous experience and carcass size. Carcass counts at power lines notably underestimate bird casualties. Our 4-week disappearance equations provide a full range of scavenging rates and observer efficiency correction factors for a wide range of bird weights. Fortnightly to monthly search frequencies may be adequate to detect medium- to large-sized corpses, but are insufficient for smaller birds. Finally, all personnel participating in carcass searches should be trained previously in this task.
Despite a growing interest in incorporating fisher knowledge into quantitative conservation assessments, there remain practical impediments to its use. In particular, there is some debate about the accuracy of fisher knowledge. In this study, we report an attempt to quantify assumptions about how accurately fishers report past events (retrospective bias). Then we examine how the assumption we make about retrospective bias affects the characterization of changes in the fishery and extinction risk. We link fisher interviews and fisher logbooks to establish a catch rate (catch per unit of effort) trend for the history of a data-poor, small-scale seahorse fishery in the Philippines. We find that fishers perceive historic declines in fishing rate that are not apparent in more recent logbook trends, and the extent of the decline (and therefore extinction risk) hinges on assumptions we make about the accuracy of fisher recall. Scenarios that ignore retrospective bias result in the most severe declines and the most worrying extinction risk classifications. Furthermore, the historic baseline set by interviews suggests that relying on recent decades of data alone may underestimate extinction risk for our study species, and others that have been historically exploited. Attempting to link interviews with logbooks also illustrates differences between fisher-derived datasets: retrospective interviews may exaggerate early fishing rates and capture less variability than logbooks. In addition to being the first seahorse fishery reconstruction, our work contributes to the emerging interest in how fisher knowledge can guide conservation assessment. Future studies that incorporate fisher knowledge into quantitative assessments require (1) clearly stated assumptions about fisher knowledge bias; (2) clear criteria to compare fisher knowledge collected with different methods; (3) evaluation of the impact of assumptions on assessments.
Effective management within the human-dominated matrix, outside of formally protected areas, is of paramount importance to wide-ranging carnviores. For instance, the largest extant population of cheetahs Acinonyx jubatus currently persists on privately owned Namibian ranchlands, and provides an excellent case study to examine and design matrix conservation approaches. Although human-caused mortality is likely the principal threat to this population, ancedotal evidence suggests that ‘bush encroachment’, the widespread conversion of mixed woodland and savannah habitats to dense, Acacia-dominated thickets, is another probable threat. A better understanding of cheetah habitat use, outside of protected areas, could be used to directly influence habitat management strategies and design local restoration and conflict mitigation efforts. To identify specific habitat characteristics associated with cheetah use, we used radio-telemetry locations to identify areas used intensively by cheetahs on commercial Namibian farms. We then compared the habitat characteristics of these ‘high-use’ areas with adjacent ‘low-use’ areas. A binary logistic regression model correctly categorized 92% of plot locations as high or low use, and suggested that cheetahs may be utilizing ‘rewarding patches’ with better sighting visibility and greater grass cover. We discuss the possible reasons for kudu Tragelaphus strepsiceros, Namibian cheetahs' preferred prey, exhibiting significantly lower abundance in high-use areas. Using habitat characteristics to identify areas intensively utilized by cheetahs has important implications for guiding future habitat restoration and developing effective predator conflict mitigation efforts.
Cheetahs (Acinonyx jubatus) held ex situ can provide an important resource for obtaining new biological information that usually cannot be gleaned from free-living individuals. However, consistent captive propagation of the cheetah, a prerequisite for establishing a self-sustaining population, has not been accomplished so far. This study examined the effect of a husbandry regimen commonly used in ex situ facilities on female cheetahs. Although generally solitary in the wild, zoos frequently house cheetahs in pairs or groups. Using non-invasive hormone monitoring and quantitative behavioural observations, we studied the impact of such enforced social conditions on behaviour and ovarian/adrenal activity. Eight female cheetahs were evaluated for two consecutive 6-month periods, first while maintained in pairs and then as individuals. Subsequently four females were regrouped into two new pairs and monitored for another 6 months. Females in five of six pairings demonstrated prolonged anoestrus and displayed agonistic behaviours. After pair separation all females rapidly resumed oestrous cyclicity. Females in the sixth pair continued cycling throughout the year while consistently displaying affiliative grooming and no agonistic behaviours. Faecal corticoid patterns varied significantly among individuals, but appeared unrelated to behavioural or ovarian hormone patterns. Thus, data appear to indicate that same-sex pair-maintenance of behaviourally incompatible female cheetahs may lead to suppressed ovarian cyclicity. This suppression appears linked to agonistic behaviours but not to any particular adrenal hormone excretion pattern. Results clearly demonstrate the value of applying knowledge about in situ social behaviour to ex situ management practices. Conversely, however, non-invasive hormone monitoring conducted ex situ may help us to identify physiological phenomena of potential relevance for future in situ studies.
Substantial genetic variation is hypothesised to be necessary for the long-term survival of species. Therefore, a major aim in conservation is to maintain and restore variation in small and endangered populations. However, in most populations the amount of genetic variation and, thus, the potential threats posed by limited variation are unknown. In the present study, we assess genetic variation, both at 10 microsatellite loci and at the major histocompatibility complex (MHC), in three closely related Acrocephalus warbler species with contrasting demographies. We found that the recently bottlenecked, island endemic, Seychelles warbler (A. sechellensis; SW) has substantially reduced microsatellite and MHC diversity compared to the widespread great reed warbler (A. arundinaceus; GRW). In contrast, another endangered species with a small breeding range, the Basra reed warbler (A. griseldis; BRW), harboured as much variation as did the GRW. This suggests that significant genetic variation and, therefore, adaptive potential, remains in the BRW – a situation that should hold as long as its habitat and numbers are maintained. Our study is one of the first to assess genetic variation at both ‘non-critical’ microsatellite markers and ‘critical’ MHC loci within endangered species. The two types of loci provided a similar picture of the genetic variation in the species we studied, but this has not been the case in studies of some other species. Using a combination of specific functional loci and genome-wide random markers appears to be the best way to assess the threat posed by reduced genetic diversity.
Decisions regarding landscape management, restoration and land acquisition typically depend on land managers' interpretation of how wildlife selects habitat. Such assessments are particularly important for umbrella species like the endangered Florida panther Puma concolor coryi, whose survival requires vast wildlands. Some interpretations of habitat selection by panthers have been criticized for using only morning locations in defining habitat use. We assessed habitat selection using a Euclidean distance analysis and location data collected throughout the diel period from GPS collars deployed on 20 independent Florida panthers. We corroborated aspects of earlier analyses by demonstrating the selection of forested habitats by panthers. We also confirmed the selection of open habitats (i.e. marsh–shrub–swamps, prairie grasslands), a novel result. Habitat selection did not vary by sex or season but varied by time of day. Panthers were located closer to wetland forests in the daytime and used prairie grasslands more at night. Our assessment of the effect of patch size on selection of forest habitat revealed that panthers were not solely reliant on large patches (>500 ha) but utilized patches of all sizes (≤1, >5–10, >1000 ha, etc.). Our results emphasize the importance of collecting panther location data throughout the diel period when assessing habitat selection. Conservation strategies for panthers should consider a mosaic of habitats, a methodology that will protect other sensitive flora and fauna in South Florida.
This study examines the population genetic structure of Asian elephants (Elephas maximus) across India, which harbours over half the world's population of this endangered species. Mitochondrial DNA control region sequences and allele frequencies at six nuclear DNA microsatellite markers obtained from the dung of free-ranging elephants reveal low mtDNA and typical microsatellite diversity. Both known divergent clades of mtDNA haplotypes in the Asian elephant are present in India, with southern and central India exhibiting exclusively the β clade of Fernando et al. (2000), northern India exhibiting exclusively the α clade and northeastern India exhibiting both, but predominantly the α clade. A nested clade analysis revealed isolation by distance as the principal mechanism responsible for the observed haplotype distributions within the α and β clades. Analyses of molecular variance and pairwise population FST tests based on both mitochondrial and microsatellite DNA suggest that northern-northeastern India, central India, Nilgiris (in southern India) and Anamalai-Periyar (in southern India) are four demographically autonomous population units and should be managed separately. In addition, evidence for female philopatry, male-mediated gene flow and two possible historical biogeographical barriers is described.
Log 10 biomass (kg/km 2 ) of ungulates, primates and rodents against Log 10 annual rainfall at tropical sites. Data and their sources are listed in Table 1. 
Biomass of large-bodied (> 1 kg) rodents, primates, ungulates and their totals at sites of different rainfalls
Actual harvests of Log 10 biomass (kg/km 2 ) of ungulates, primates and rodents against Log 10 annual rainfall at tropical sites. 
Overlay of maximum sustainable offtake curve (= supply: broken line) and harvest curve (= demand: continuous line) plotted against annual rainfall at tropical sites. 
Hypothesised supply (broken line) and demand (continuous line) curves in tropical forest areas that have been influenced by human activities, with relatively undisturbed forest being converted into secondary forests and pasture. 
Unsustainable hunting of wildlife or bushmeat for human consumption across the tropics threatens both wildlife populations and the livelihoods of people who depend on these resources. The probability that hunting can be sustainable depends in part on ecological conditions that affect the ‘supply’ of and ‘demand’ for wildlife resources. In this study, supply is estimated across a number of tropical ecosystem types by calculating the theoretical ‘maximum sustainable offtake’ in kg/km2 for harvestable wildlife. Demand is estimated from observed harvests in kg/km2. We examine how supply and demand vary across relatively undisturbed ecosystems, indexed by annual rainfall. Supply is potentially highest in dry forests and wetter savannah grasslands and decreases in moist forests and more xeric grasslands. Demand tends to exceed supply in moist forests and xeric grasslands. Analogous to this ecological variation along the rainfall gradient is the gradient created by the conversion of tropical forests by humans. We hypothesise that the wild meat supply is greater in secondary forests and forest–farm–fallow mosaics than in undisturbed forests and test this with available data. We conclude that the probability that hunting will be sustainable varies with ecosystem type and degree of human disturbance and should influence where land is zoned for protected areas and where for wildlife harvests.
Predation is a constant risk for most primates, impacting demography, population dynamics, activity patterns and social behaviour. Data are limited on both the rates of predation and its spatial and temporal variability. We present long-term observations of Cryptoprocta ferox predation on rainforest sifakas in Madagascar, Propithecus diadema at Tsinjoarivo (22 group years) and Propithecus edwardsi at Ranomafana (73 group years), derived from intensive observations based on ongoing behavioural studies. Average per capita offtake rates are relatively low (0.06–0.07), but temporal variability is high (kills are clumped in time). This is consistent with Cryptoprocta ecology; individual home ranges are much larger than sifaka ranges, and individuals may hunt in a subsection of their range until prey density is decreased, then move on. These results have broad implications. First, in terms of the evolution of anti-predator strategies, it now becomes important to ask: (1) whether average or peak predation rates determine the strength of selection and (2) whether antipredator strategies (e.g. vigilance, sleeping site selection) fluctuate interannually, reflecting recent experience. Second, in terms of population ecology, Cryptoprocta may have disproportionately large impacts on the (small) sifaka groups, even driving groups to extinction (as observed at both sites). Third, the disappearance of groups has important implications for conservation. When this happens in continuous forest (as at Ranomafana), home ranges will likely be re-filled over time, whereas in isolated forest fragments (as at Tsinjoarivo), recolonization is less likely. Thus, conservation planners should consider predation as a potentially important proximate cause of extirpation in fragmented landscapes, even when resource density and quality could otherwise sustain populations. Considering the effects of predation can be useful in (1) decisions regarding the allocation of limited conservation resources, including which landscapes to invest resources in and (2) investigating ways to increase resilience of prey species.
Pelage characters and their character states for non-colour characters. All characters scored 3 each in A and all characters in B scored 1 each except character-14 (tabby pattern).  
Frequency distribution of the total pelage scores (TPSs) for each cat Group.
The percentage of wild-living cats in Groups 1–3 with pelage scores of 2 or less for the seven key pelage characters.  
A recent estimate suggests that the Scottish wildcat may be critically endangered. Nevertheless, there is still no uncontroversial method for diagnosing the Scottish wildcat. We analysed morphological differences between wild-living cats in Scotland on the basis of 20pelage characters, scoring from 1 (domestic cat) to 3 (wildcat), in combination with 40skull parameters and intestinal length. A cluster analysis, based on Principal Components derived from the scores for pelage characters, showed that the wild-living cats fell into three main groups without any a priori classification. Each group corresponds well to the traditional characteristics of wildcats, hybrids and domestic cats, respectively, and the former two each show higher levels of morphological homogeneity compared with the third group. The three groups are most significantly differentiated by seven pelage characters: (1) extent of dorsal stripe, (2) shape of tail tip, (3) distinctness of tail bands, (4) presence/absence of broken stripes and (5) spots, on flanks and hindquarters, (6) shape and number of stripes on nape and (7) on the shoulders. Most Group-1 cats (75.6%, n=74), but none of the other two groups, score more than 2 for all seven characters. All Group-3 cats (n=35) and some Group-2 cats (19.2%, n=26), but no Group-1 cats, scored 1 for one or more of the seven characters. We propose that Group-1, which is the furthest from the domestic cat in all criteria, should be used to define the Scottish wildcat. However, in practice, if a wild-living cat does not score 1 for any of the seven characters it should be treated as a wildcat in the field. These definitions provide a simple way of diagnosing a Scottish wildcat scientifically, as well as practically, which will effectively facilitate conservation action and the enforcement of protective legislation.
Madagascar is a biodiversity hotspot threatened by habitat loss, which is detrimental to the future survival of forest-dwelling herpetofauna. For conservation purposes, it is essential to determine how species respond to different types of anthropogenic habitat alteration. We conducted standardized field surveys (a variation of visual encounter survey) to assess species richness, abundance and diversity among forest, clear-cut and orchard habitat types in Montagne des Français, north Madagascar. Forest sites proved to be very different from clear-cut and orchard sites with regards to habitat structure. Lizard species richness, abundance and diversity were significantly lower in clear-cut sites, with only 11% of the observed forest diversity recorded. This shift in species occurrence suggests that lizards are particularly sensitive to this type of habitat alteration. Orchard cultivation did not affect lizard species richness to the same extent, as 56% of the observed forest diversity was recorded in this habitat type. Furthermore lizard abundance was significantly higher in orchard habitat. These observations indicate that although anthropogenic activity can have an adverse effect on the lizard fauna of a given site, it will seldom lead to a total loss of diversity as species typical of pristine forest (specialists) are replaced by species adapted to secondary habitats (often generalists). Our results support the contention that anthropogenic habitat alteration can have a strong negative influence on lizard communities. Researchers should continue to identify which species may be lost or become more vulnerable in future (as a result of population decline) in response to anthropogenic habitat alteration.
Limitation of disturbing activities around the breeding areas of protected species is not always possible, if these activities are economically important and have, in addition, positive effects on protecting the habitats of those protected species. Searching for optimal solutions making commercial exploitation of natural resources compatible with biodiversity conservation is thus of concern to managers and policy makers. This is the case of the cinereous vulture Aegypius monachus, breeding primarily in cork-oak woodland, and cork exploitation, a traditional socio-economic activity carried out in several Mediterranean countries, and critical for the maintenance of this important habitat. We studied the effects of this anthropogenic activity on the behaviour and breeding success of breeding cinereous vultures in Spain. For the adults, the probability of nest abandonment was dependent on the distance of workers from the nest and the level of noise; activities within 500 m from the nest were likely to cause abandonment of the nest by adults, if the level of noise was intermediate or loud. Neither the size of the working group nor the use of machines per se, had any effect on the probability of nest abandonment. Pairs in an area of the colony exposed to intrusive anthropogenic activity had 20% lower breeding success than those in the same colony that were not exposed to these disturbances. If the application of buffer zones of 500 m is not possible (as is likely given the economic losses involved), several alternatives are recommended based on our results to minimize the impact of these activities, in particular to diminish the noise level of cork extraction activities. Observational studies like this help understanding the magnitude of the problem and finding alternative solutions for harmonizing conservation and economic development.
We studied (14 500 h of field observations during 20 breeding attempts by 10 pairs) the effects of human activities on the behaviour of breeding Spanish imperial eagles. The probability that human activities around nest sites provoked a flight reaction varied significantly among territories and among types of activity, and increased when the distance between the activity and the nest site decreased, and increased when the number of people involved in each intrusion was higher. Pedestrian activities (mainly by hunters, campers and ecotourists) caused more flight reactions than vehicles. Overall, the probability of a reaction increased sharply when activities occurred at less than 450 m from the nest, but was negligible if they occurred at 800 m. Reaction probability was lower in territories with higher intrusion frequencies (which suggests that some habituation occurs), where the nest was not visible from the tracks, and in less ‘plain’ or ‘accessible’ territories. Hatching rate was affected negatively by the frequency of human activities. Our results suggest that the critical inner buffer zone around Spanish imperial eagle nests should be established at a minimum radius of 500 m, and the vulnerable zones at a minimum of 800 m, bearing in mind the physiography of the terrain and the visibility of the nests. Finally, in future studies of nest-site selection with this species, it would be advisable to use a variable that quantifies (through field observations) human disturbance frequency.
Habitat loss, electrocution on power poles and persecution by humans are the main threats to birds of prey. Nevertheless, the effects of human disturbance on endangered species are becoming notorious due to the increasing recreational use of the natural environment. We evaluated the effects of human disturbances on Egyptian vulture Neophron percnopterus breeding success and developed conservation measures based on minimum distance of effect and buffer areas in a high human density area of northern Spain. A total of 100 breeding attempts of 15 breeding pairs were monitored over 8 years. Human disturbances affected 42 of the breeding attempts. Those disturbances related to and originating in forestry work had the most severe effect on breeding success, being associated with the loss of 100% of 13 breeding attempts, while human disturbances related to free-time activities caused 44% failures in 25 breeding attempts by four pairs, two of them within Natural Parks. The breeding success was significantly less in territories affected by disturbances than in those free of disturbances. Some pairs affected by disturbances changed their nest site, increasing breeding success. Adults were prevented from entering the nest to feed chicks when anyone was detected at an average distance of 307 m, while an average distance of 837.5 m allowed them access. The maximum alert distance was estimated at 605 m and the buffer area was 57 ha. We discuss the application of our results for management schemes and conservation of this species.
Number of transactions and biomass (kg) of wildlife and fish sold between March 2005 and May 2007 at a wild meat market at Pompeya, in the northern border of Yasuní National Park (Ecuadorian Amazon)
Temporal trend (2005–2007) of the trade of wild meat (fish, mammals, birds and reptiles) in the market of Pompeya in the northern border of the Yasuní National Park, in the Ecuadorian Amazon. Mean ± standard deviation.
Regression model relating the amount of wild meat sold in the Pompeya market (north-eastern Ecuador) and the actual cost of transportation (boat or bus ride fares) between the Pompeya and several indigenous communities in the region () (Biomass=463.94 × e−0.783(cost); r2=0.51; P=0.015).
Prices (US$ kg−1, mean and standard deviation) of meat of pacas Cuniculus paca, of other wildlife species, and of domestic meat at different towns in the area of influence of the wild meat trade chain in the northern portion of the Yasuní National Park.
Average prices (US$ kg À1 ) of fish, wild meat and pacas Cuniculus paca sold between March 2005 and May 2007 at a wild meat market in Pompeya, near Yasuní National Park, in north-eastern Ecuador Price (US$ kg À1 )
Starting in 1994, a wholesale wild meat market developed in north-eastern Ecuador, involving Waorani and Kichwa people in the area of influence of a road built to facilitate oil extraction within Yasuní National Park. Between 2005 and 2007, we recorded the trade of 11 717 kg of wild meat in this market, with pacas Cuniculus paca, white-lipped peccaries Tayassu pecari, collared peccaries Pecari tajacu and woolly monkeys Lagothrix poeppiggi accounting for 80% of the total biomass. Almost half of the wild meat brought to the market was transported by dealers for resale at restaurants in Tena, a medium-sized town 234 km west of the market. Prices of wild meat were 1.3–2 times higher than the price of meat of domestic animals, suggesting that it is a different commodity and not a supplementary protein source in the urban areas where it is consumed. The actual price of transportation between the local communities and the market was a significant predictor of the amount of meat sold in Pompeya. Based on this relationship the Waorani hunters sold exceptionally larger amounts of wild meat than would be expected if they would not have the transportation subsidies provided by the oil companies. Although the scale of this wild meat wholesale market is still relatively small, its dynamic reflects the complex interactions that emerge as the overriding influence of oil companies or other private industries modify the culture and subsistence patterns of marginalized indigenous groups, increasing their potential impacts on wildlife and natural ecosystems.
Genetic adaptation to captive environments is likely to reduce the reproductive fitness of endangered species when they are reintroduced into natural environments. Equalization of family sizes is predicted to halve genetic adaptation to captivity as it removes selection among families and is recommended in captive management of threatened species. This prediction was evaluated by comparing the reproductive fitnesses of replicate populations of Drosophila maintained using either equal (EFS) or variable family sizes (VFS) for 25 generations in captivity under uncrowded conditions on a medium containing CuSO4. After 25 generations, EFS populations produced 8.8% more offspring per pair than their outbred base population on CuSO4 medium, while VFS produced 17.5% more. Consequently, the rate of genetic adaptation to captivity in EFS was about half that in VFS, as predicted. In simulated ‘wild’ conditions (crowded, competitive conditions on medium lacking CuSO4), both treatments showed much lower reproductive fitness than their outbred base population, the reductions being 38% in EFS populations and 43% in VFS populations. Surprisingly, reproductive fitness of the two treatments did not differ significantly under these conditions. These results raise doubts about the ability of equalization of family sizes to reduce genetic deterioration that adversely affects reintroduction success for captive populations of endangered species.
The arrival of an invasive species can have severe impacts on native species. The extent of the impact, as well as the speed at which native species may mount an adaptive response, depend upon the correlation between impact and the individual phenotypes of the native species. Strong correlation between phenotype and impact within the native species raises the possibility of rapid adaptive response to the invader. Here, we examine the impact of a dangerous newly arrived prey species (the highly toxic cane toad Bufo marinus) on naïve predators (death adders Acanthophis praelongus) in northern Australia. During laboratory trials and field radiotracking, toads killed 48% of the adders we studied. Long-term monitoring of the population also suggests a massive decline (>89%) in recent years concurrent with the arrival of toads. Variation in snake physiology (resistance to toad toxin) had little bearing on snake survival in the field. Snake behaviour (tendency to attack toads) and morphology (body size and head size), however, were strong predictors of snake survival. Smaller snakes with relatively small heads, and snakes that were unwilling to attack toads in the laboratory, had much higher survival rates in the field. These results show that toads have a massive impact on death adder populations, but that snake phenotypes strongly mediate this impact. Thus natural selection is operating on these adder populations and an adaptive response is a possibility. If these adders can rapidly shift toad-relevant morphological and behavioural traits (either through plastic or evolved means), they will ultimately face a lowered impact from this toxic invader.
Total number of small lizards (Podarcis melisellensis, Dalmatolacerta oxycephal, Tarentola mauritanica) recorded for the surveyed islands.
We studied impacts of the introduced small Indian mongoose Herpestes auropunctatus on the herpetofauna on six islands in the Adriatic Sea, Croatia, comparing abundances of reptiles and amphibians on three islands with the mongoose to those on three islands without the mongoose. We used four types of sampling surveys: distance-constrained surveys, visual encounter surveys, special searches and accidental trapping. The horned viper Vipera ammodytes and Balkan green lizard Lacerta trilineata were absent from two mongoose-infested islands (Korčula and Mljet) and rare on the third (Hvar); they were common only on the mongoose-free island where they had historically been present (Brač). The European green toad was absent from one mongoose-infested island, where it had historically been present and rare on the other two. It was common on two of the three mongoose-free islands. Other herpetofaunal species were either very scarce or completely absent on the three mongoose-infested islands. Most of these species also occur on the mainland but are already scarce there; some are strictly protected under Appendix II of the Berne Convention. The recent spread of the mongoose to the European mainland suggests the need for urgent control to protect vulnerable herpetofauna.
The lesser kestrel Falco naumanni is a globally threatened colonial bird that has suffered a generalized population decline in Europe. Recent studies have suggested that the land-use changes linked to agriculture intensification are the main factors accounting for the population regression. However, there has been little analysis of the role of pesticide applications. In this study, we examined the consequences of a malathion treatment in a wild population of lesser kestrels, specifically its effects on breeding performance, adult survival and population size. We found that the larger the area treated with malathion around the colony, the lower the size and the body condition of the fledglings, although no effects were found on the number of fledged chicks per pair or their sex ratio. Survival of adult males, but not females, was lower in the malathion-treated areas. These results show that organophosphorus pesticides applied at standard rates might disrupt the lesser kestrel population dynamics by reducing their breeding performance and increasing adult mortality in a sex-biased way. The proportional area treated around the colony did not affect colony size in the following year, indicating that an increased adult male mortality was not enough to lead to a detectable population size reduction and/or that the arrival of immigrants could have masked it. Both the direct malathion toxic effects and the expected reduction in prey availability due to fumigation are likely to underlie the observed effects. Hence, keeping non-treated buffer areas around kestrel colony centers should be a strictly applied conservation measure to avoid the observed negative side effects of malathion applications.
Although reintroduction programmes are often implemented for recovering animal populations, projects seldom monitor the long-term survival of released animals. In addition, although many releases may occur in the same area, little is known about how the survival of successive release batches is affected by the presence of conspecifics and density dependence. Here, we use multi-state capture–recapture modelling (combining information from recaptures and recoveries) to analyse the survival of two batches of Hermann's tortoise Testudo hermanni hermanni released in a 10-year interval and monitored for 18 years at the Ebro Delta (western Mediterranean). We also tested whether the released animals experienced lower survival (i.e. a release cost) before becoming familiar with the new environment. Although we used a hard-release method, neither group experienced a short-term release cost. Annual survival of both groups differed and was not negatively affected by density-dependent factors. Annual survivorship of the first group of released tortoises was constant and very high (0.945, se=0.011), and similar to that estimated from several natural populations. The presence of a terrestrial predator in 1 year (before the release of the second group) significantly decreased the survival of tortoises (0.819, se=0.073). Strikingly, survival of the second batch was significantly lower than that of the first group after the first years of release (0.775, se=0.049). Although survivorship for the first group suggested that habitat quality was high, the second group seemed not to acclimate well to the new environment, possibly due to the presence of resident tortoises. From a management perspective, reintroduction programmes of the Hermann's tortoise are a successful strategy for its recovery. Nevertheless, it seems advisable to avoid: (1) the release of tortoises at the core of well-established populations and (2) areas with a high density of predators, which can jeopardize the reintroduction success, especially when the number of released individuals is small.
Study area showing Bhadra Wildlife Sanctuary and the surrounding coffee plantations.
Response of various families, feeding guilds and size classes to distance from the PA and canopy cover (n = 25 transects)
Although large areas of relatively undisturbed forests are essential for preserving biodiversity, opportunities for conservation in human-dominated landscapes must not be overlooked. Agroforestry systems such as shaded coffee plantations are known to be more compatible with biodiversity conservation than other, more drastic, land transformations. In recent times, however, modernization of coffee cultivation has influenced its conservation values adversely. We evaluated adult butterfly diversity in 12 coffee plantations around a protected area (PA) in the Western Ghats, India. We sampled 25 transects that varied in distance from the PA and in proportion of silver oak Grevillea robusta, an exotic timber species. We also had two transects within the PA. We used a combination of line transects and fruit bait traps to sample butterflies. Micro-climatic variables (temperature, humidity and light intensity) and other habitat variables (e.g. canopy cover, tree diversity, herb species richness) were recorded for each transect. We analyzed the effect of these variables on the abundance and species richness of butterflies, overall as well as in different families, feeding guilds and size classes. Proximity to the PA significantly influenced the abundance and richness of butterflies in coffee plantations, with transects close to the PA having higher abundance and richness than transects further away. Also, in terms of butterfly species composition, similarity to forest declined with increasing distance. Among the habitat variables, only canopy cover had a significant effect on abundance and richness, and the effect was negative. These patterns, with some exceptions, were also reflected for different families and feeding guilds. The proportion of silver oak had no apparent effect on butterflies. This study demonstrates that coffee plantations can act as a buffer for butterfly fauna within a certain radius of a PA. They have great potential as auxiliary tools and can significantly complement conservation efforts that are currently centered on PAs.
Top-cited authors
Timothy G O'Brien
  • Wildlife Conservation Society
Margaret F. Kinnaird
  • WWF-International
Rosie Woodroffe
  • Zoological Society of London
Amy Dickman
  • University of Oxford
Hariyo T. Wibisono
  • Fauna - Flora International - Indonesia Programme