Evaluation of translocation as a tool for mitigating development threats to great crested newts (Triturus cristatus) in England, 1990-2001

Great crested newts (Triturus cristatus) are protected under European and UK legislation, but are frequently the subject of conflict between development and conservation in England. When this occurs, the developer is legally obliged to instigate a mitigation plan to reduce the impacts on the newts. This usually involves the translocation of newts coupled with habitat enhancement and creation. We reviewed mitigation projects carried out in England between 1990 and 2001 by (1) analysing licensing information collected by the governmental licensing authorities; and (2) a questionnaire survey of a sample of mitigation projects. Over half of the licensed projects on file contained no report of the work undertaken. There was an increase in the number of new translocation projects from less than 10 a year in the early 1990s to over 80 a year by 2000. This translates into about £1.5 million per year currently being spent on great crested newt mitigation projects. Most of these projects involved in situ translocations of newts to areas within or adjacent to the development site. The number of newts translocated per project declined over the same period, and was related to the total area of habitat destroyed and work effort. About 27% of great crested newt terrestrial habitat was destroyed during the developments along with about half of all ponds. Although the number of new ponds created compensated for the number of known great crested newt ponds lost, there was a net loss in terms of overall area of aquatic habitat. Where follow-up monitoring of translocations was conducted, there was evidence of breeding at most sites one-year post-development, but it is unclear whether these populations were sustainable in the long-term.     

Habitat correlates of distribution and local population decline of the endemic Sardinian newt Euproctus platycephalus

Habitat-based statistical models relating patterns of presence and absence of species to habitat variables could be useful to resolve conservation-related problems and highlight the causes of population declines. In this paper, we apply such a modelling approach to an endemic amphibian, the Sardinian mountain newt Euproctus platycephalus, considered by IUCN a critically endangered species. Sardinian newts inhabit freshwater habitat in streams, small lakes and pools on the island of Sardinia (Italy). Reported declines of newt populations are not yet supported by quantitative data, however, they are perceived or suspected across the species' historical range. This study represents a first attempt trying to statistically relate habitat characteristics to Sardinian newt occurrence and persistence. Linear regression analysis revealed that newts are more likely to be found in sites with colder water temperature, less riparian vegetation and, marginally, absence of fish. The implications of the results for the conservation of the species are discussed, and suggestions for the short-term management of newt inhabited sites suggested.     

Optimising biodiversity assessments by volunteers: The application of occupancy modelling to large-scale amphibian surveys

Mobilising volunteers to carry out biodiversity assessments can help to identify priorities for conservation across broad geographical scales. However, even when volunteers carry out simple presence-absence surveys, there can be significant issues over false absences and subsequent data interpretation. Simple but scientifically robust protocols are therefore required for these programmes. Here we evaluate amphibian survey protocols for the National Amphibian and Reptile Recording Scheme (NARRS) in Britain, which aims to assess the status of five widespread amphibian species. Surveys were undertaken by trained volunteers and researchers in two contrasting landscapes over 2 years, and occupancy modelling was used to determine covariates of detection, and to optimise the number of surveys and number of methods required. Although surveys need to take into account seasonal and annual changes in the detectability of different species, there were also landscape effects. Frogs and toads were generally harder to detect in ponds in Kent than in Wales, while the converse was true of newts. Adding bottle-trapping to the suite of methods increased the detection of smooth and palmate newts in both areas, and of great crested newts in Wales. Overall, reliable assessment of the presence or absence of all five species at a site required four separate surveys, each using four different methods (visual encounter surveys during both day and night, dip netting and bottle-trapping). Our approach may prove useful for finding the best compromises between rigor and simplicity when volunteers are used in large-scale surveys.     

Abundance, body size and movement patterns of a tropical treefrog in continuous and fragmented forests in the Brazilian Amazon

Phyllomedusa tarsius is a hylid frog that breeds in ponds located in a range of habitats from continuous forests to severely disturbed matrix habitats in Central Amazon. During three reproductive seasons, we followed the movement patterns, measured body size and registered abundance and residency time of this species in five habitats: pasture, Vismia regrowth, Cecropia regrowth, 1 and 10 ha forest fragments, and continuous forest. The frog captures were strongly correlated with rainfall in all disturbed habitats, but not in continuous forest, probably because individuals respond more directly to rainfall patterns in more open habitats. Males in disturbed habitats were smaller than those found in continuous forest, perhaps as a result of differences in habitat quality. Males remained at sites for longer periods in fragments and continuous forest compared to matrix habitats. Here again, the quality and suitability of breeding sites in matrix habitats may be lower than in continuous forest resulting in the need for more movement. We found bigger subpopulations in matrix habitat ponds and a higher percentage of individuals moving among them when compared to continuous forest ponds. Constant movement of individuals among disturbed subpopulations decreases population isolation and increases interbreeding among different subpopulations. No movement between individuals from continuous forest ponds and disturbed habitats was observed. This suggests that the disturbed habitat subpopulations are not acting as sink subpopulations for continuous forest populations. The maintenance of individuals in fragments is more dependent on local conditions for reproduction and on subpopulations in the matrix habitat than on recruitment of individuals from populations in continuous forest.     

Traditional salt-pans hold major concentrations of overwintering shorebirds in Southeast Asia

Shorebirds are declining worldwide due to loss and degradation of critical breeding and wintering habitats. Some human-modified habitats, particularly salt-pans which are used by shorebirds in many regions of the world, may help substitute for natural habitats lost for a wide range of species during migration. We studied the influence of landscape characteristics on species richness, abundance, and diversity of shorebirds at 20 sites covering most of the Inner Gulf of Thailand, a landscape with a long history of salt farming. Sites with salt-pans present held significantly higher species richness, abundance and diversity of shorebirds. Areas with larger proportions given over to aquaculture tended to have lower species richness, abundance and diversity. Generalized additive models indicated that landscapes with a larger proportion of tidal flats in conjunction with salt-pans were the best predictors of sites with higher species richness, abundance and diversity. Landscape configurations with higher richness, abundance and diversity of shorebirds also tended to be less fragmented and contained slightly larger patches. Shorebirds appeared to use ponds with exposed mud in salt-pans as both roosting sites and supplementary feeding grounds during high tide. Traditional salt-pans therefore proved to contribute significantly to maintenance of overwintering shorebird populations in this landscape and should be investigated elsewhere in Asian coastal zones. Collaboration between researchers, salt farmers and planning authorities as to how best to maintain salt-pans as potential shorebird roost sites such as in the Inner Gulf of Thailand is urgently needed in order to maintain habitat for shorebird populations in critical wintering and staging areas of this flyway.     

A multi-scale approach to facultative paedomorphosis of European newts (Salamandridae) in the Montenegrin karst: Distribution pattern, environmental variables, and conservation

Facultative paedomorphosis, a process in which newt larvae can opt for reproduction before or after metamorphosis, is geographically heterogeneous. Despite numerous ecological studies and recent evidence of declines in paedomorphic populations, however, no attempt to model environmental variables that explain the presence of paedomorphs has been made at a multi-scale level. Our aim was to fill this gap in studying three newt species (Lissotriton vulgaris, Mesotriton alpestris, and Triturus macedonicus) of the Montenegrin karst as model species. To this end, we used multivariate analysis on three scales of habitat: the breeding pond, the land use and the climatologic features. Results show that the study area is both an important hotspot for paedomorphosis and where intraspecific diversity is quickly disappearing (20-47% extirpation) because of fish introductions. Other habitat variables (water permanency, pH or the habitat origin) were shown to act on paedomorphosis but not consistently across species, confirming complexity of the evolutionary and ecological processes. This study appeals for more long-term and detailed landscape studies of polyphenisms, a neglected but promising topic, to better understand and protect alternative modes of development. Particularly, measures should be taken to identify hotspots of intraspecific diversity at a global scale and stop fish introductions before we reach a point of no-return.     

Sex and seasonal differences in the spatial terrestrial distribution of gray treefrog (Hyla versicolor) populations

Fragmentation of terrestrial landscapes has exacerbated the need to understand the spatial requirements of organisms, especially those that undergo seasonal migrations, such as pond-breeding amphibians. Pond-breeding amphibians spend much of their lives in terrestrial habitat at some distance from aquatic breeding sites. The terrestrial habitat required by a particular individual encompasses the area adjacent to a breeding pond that is used for activities such as foraging or overwintering, as well as the expanses of habitat through which it moves. To elucidate amphibian spatial habitat requirements, we monitored gray treefrog (Hyla versicolor) movements through terrestrial habitat adjacent to breeding ponds using radiotelemetry and mark–recapture along transects of artificial refugia. Results indicate that gray treefrogs frequently make migrations between foraging grounds, overwintering sites, and breeding ponds of 200 m or more, with a maximum-recorded movement distance of 330 m. Additionally, females travel farther than males for reasons independent of body size, and the distribution of males during the breeding season is biased towards breeding ponds relative to the non-breeding season. The data illustrate the importance of habitat directly adjacent to breeding sites for males, and indicate that habitat loss resulting in small patches may have a greater negative impact on females than males, and consequently may have disproportionately large effects on population persistence. These results emphasize that effective management of amphibian breeding locations via protection of both aquatic and adjacent upland terrestrial resources likely requires detailed information regarding variation in movements between the sexes and among seasonal activity periods.     

Effects of landscape composition, habitat features, and nest distribution on predation rates of simulated turtle nests

We investigated predation of simulated turtle nests in an effort to understand how land-use patterns and the availability of nesting habitat may affect turtle recruitment in a region where human populations and associated development are increasing. Simulated nests were patterned after those created by painted turtles (Chrysemys picta), a common aquatic turtle in our study area, and distributed in four patterns (clustered and near pond, scattered and near pond, clustered and far from pond, and scattered and far from pond) around 36 ponds. Landscape composition (500-2000 m from pond perimeters) and habitats surrounding pond edges (an area extending 250 m from the shore of each pond) were then compared with rates of predation at each pond. Nest-site characteristics also were compared to the fate of individual nests. Landscape composition and habitats surrounding ponds apparently had little influence on predation rates. Nest distribution and the immediate habitat features associated with each nest did affect vulnerability to predation. Clumped nests were preyed upon at a higher rate than scattered nests, and nests close to ponds (within 50 m) were more vulnerable to predators than those created far (100-150 m) from a pond. Counter to our expectations, proximity to edge habitats (other than the shore of a pond) reduced the probability that a nest would be detected by predators. Also, nests placed near roads and suburban lawns had a reduced likelihood of predation whereas those placed in agricultural areas or disturbed sites had a greater probability of being preyed upon. Our results suggest that predation of simulated turtle nests may be a consequence of their distribution and location relative to the foraging activities of common nest predators, especially raccoons (Procyon lotor). Efforts to enhance recruitment among declining populations of turtles should consider the abundance and distribution of nesting habitat. Providing additional nesting sites away from predator foraging habitats may reduce nest predation and increase the recruitment of hatchlings into a population.     

Influence of connectivity, habitat quality and invasive species on egg and larval distributions and local abundance of crucian carp in Japanese agricultural landscapes

The quality of habitat at and around a spawning site, and the availability of movement between spawning and nonspawning habitats are likely to be important determinants for population persistence in a degraded and fragmented landscape. We assessed the influence of habitat connectivity, habitat quality and invasive species for distributions and local abundance of eggs and larvae of crucian carp (Crassius auratus complex, which is listed as “data deficient” on the Japanese Red List) in agricultural landscapes surrounding Lake Mikata, Japan, where drainage ditches and paddy fields are extensively utilised for spawning (lake or river shores are also used). We investigated the presence and abundance of eggs and larvae of crucian carp and habitat components at 146 sites across a range of presumed spawning habitats. Egg presence was affected strongly by connectivity to the lake (watercourse distance from the lake), and egg abundance was significantly influenced by both connectivity and habitat quality. In contrast, larval presence was primarily related to habitat quality. Larval abundance was influenced by connectivity and habitat quality, but the effect of connectivity was relatively low. Furthermore, larval abundance was negatively related to the presence of the invasive species red swamp crayfish (Procambarus craki) and bullfrog (Rana catesbeiana). Our findings indicate that connectivity, habitat quality and the presences of invasive species are crucial in determining suitable spawning and nursery habitats, but their relative importance may vary depending on egg and larval life stages. We suggest that restoring connectivity, improving habitat quality and removal of invasive species could be effective conservation strategies for the declining populations of crucian carp in agricultural landscapes.     

Effect of the landscape context on the density and persistence of a predator population in a protected area subject to environmental variability

Protected areas are the most important tool for the conservation of biodiversity. However, many species are area-demanding and their populations seldom meet their space requirements in reserves. In this context, the unprotected exterior becomes an important part of their home range, and variations in habitat quality of the surroundings of a protected area might affect the dynamics of populations. Using a spatially explicit simulation model, we studied the effect of the surrounding landscape of a protected area on the density and persistence of a predator population inhabiting inside the reserve in different conditions of environmental variability. We simulated individuals of a predator population, their herbivorous prey and a vegetative substrate in a landscape comprised of a square protected area and different types of habitat quality outside the reserve. We studied the combination of three substrate qualities of protected area (inside) with three of the landscape context and three levels of variability of productivity. Our results showed that there were strong effects of both the relative quality of the surrounding landscape and of the environmental variability on the density and persistence of the simulated population inside the protected area. More importantly, we showed that complex patterns emerge when spatial heterogeneity and temporal variability interact with population dynamics. Specifically, under high environmental variability, when the protected area had a high habitat quality, the highest population persistence was not attained when the exterior was also of high quality, but when the surroundings had an intermediate quality. The latter result suggests that, under the mentioned conditions, small enhancements in the quality of the matrix may have, for some species, better effects on increasing persistence in small reserves than large and costly enhancements.     

The abundance of a threatened arboreal marsupial in relation to anthropogenic disturbances at local and landscape scales in Mediterranean-type forests in south-western Australia

This study investigated associations between the relative abundance of the threatened ngwayir (western ringtail possum, Pseudocheirus occidentalis) and anthropogenic disturbances at local and landscape scales within the publicly-managed jarrah (Eucalyptus marginata) forests of south-western Australia. Logging, fire, fox (Vulpes vulpes) control and forest fragmentation were investigated in relation to the relative abundance of ngwayir at 90 sites within an area of 285,000 ha east of Manjimup; the location of the last remaining substantial population of ngwayir in jarrah forest. Overall, ngwayir abundance was greatest in areas with limited anthropogenic disturbance. At the local-scale, ngwayir abundance was negatively associated with greater fire intensity. At the landscape-scale, it was positively associated with fox control and negatively associated with forest fragmentation and distance from non-remnant vegetation (i.e., agriculture and tree plantations). Abundance was also greatest in predominantly unlogged landscapes and in forests that had been regrowing for an average of 40 years since the landscape was most recently logged, in other words, where logging was historically least intense. Interactions between fox control efforts and forest fragmentation were also important. This study emphasises the importance of conducting research at appropriate spatial scales and to account for the synergistic effects of the causes of decline. An adaptive management approach to the mitigation of the agents of decline is recommended.Indirect evidence indicates that high value habitat for ngwayir has in all likelihood been selectively cleared for agriculture, owing to its fertile and productive nature. Habitat loss is, therefore, also likely to be a major cause of the modern decline of the species. While many jarrah forest areas that support remaining high abundances of the ngwayir have been incorporated into reserves, conservation of ngwayir habitat and populations outside reserves also will be essential for the recovery and long-term viability of the species.     

Mortality at wind-farms is positively related to large-scale distribution and aggregation in griffon vultures

Wind-farms have negative impacts on the environment, mainly through habitat destruction and bird mortality, making it urgent to design predictive tools to use in landscape planning. A frequent assumption of wind-farm assessment studies is that bird distribution and abundance and bird mortality through collision with turbines are closely related. However, previous results are contradictory and question the usefulness of these variables to select safer wind-farm locations. We focused on a species highly vulnerable to collision at wind-farms, the griffon vulture, to test whether mortality at turbines was related to the relative position of turbines within the vulture population. We used the location of all turbines on 34 wind-farms in southern Spain, details on 342 griffon vultures found dead, and the location and size of breeding colonies and roost sites of the species during the breeding and non-breeding seasons, respectively. Using variables that describe the large-scale distribution and aggregation of vultures, we found that year-round mortality at turbines increased when they were located in highly populated areas, a result that can be translated into management guidelines to plan wind-farm locations.Bird abundances can help to guide wind-farm plans at large scales. Current protocols of counting birds at specific points during particular periods of time have low predictive power. However, other more integrative cues such as the spatial distribution and aggregation of some vulnerable species should be used as criteria for large-scale environmental planning. Local inspection of the relationship between mortality at existing turbines and their relative position within the spatial distribution of bird populations can guide managers in planning future wind-farms and in managing currently operating developments.     

Habitats of the British amphibians (2): suburban parks and gardens

An investigation was made into the use of park and garden ponds as breeding sites by amphibians in Sussex, England. Of the five common British species, three were widespread in the study area; in order of abundance (of records) these were: Rana temporaria > Triturus vulgaris > Bufo bufo. Although more or less randomly distributed with respect to each other, records of amphibians generally became scarce near the most intensively developed areas of town centres. Neither pond volume, age nor local geology seemed to exert significant effects on species distribution. Aquatic vegetation was also unimportant, but fish did prove to be a relevant factor: toads tended to be absent from ponds not containing fish, whereas newts demonstrated a slight preference for such pools. Neither pH nor ionic score correlated with the distribution of any of the three species individually, but large old ponds of high ionic scores were associated with a greater abundance of toads compared with frogs in situations where the two species occurred together. Surveys indicated that in the study area about 15% of gardens contained ponds and of these at least 50% were used as breeding sites by amphibians.     

Extension of landscape-based population viability models to ecoregional scales for conservation planning

Landscape-based population models are potentially valuable tools in facilitating conservation planning and actions at large scales. However, such models have rarely been applied at ecoregional scales. We extended landscape-based population models to ecoregional scales for three species of concern in the Central Hardwoods Bird Conservation Region and compared model projections against long-term trend data from the North American Breeding Bird Survey. We used a spatially-explicit demographic model and structured the regional population into ecological subsections on the basis of habitat, landscape patterns, and demographic rates to assess species viability. Our model projections were within 2% of the Breeding Bird Survey trends over the last 40 years for each species. Wood thrush (Hylocichla mustelina) populations remained relatively stable over the simulation and worm-eating warbler (Helmitheros vermivorus) abundance increased throughout most of the time period until reaching carrying capacity. In contrast, the prairie warbler (Dendroica discolor) population steadily declined by 0.59% annually. The combination of habitat and demographic modeling allowed us to create models that address processes driving these populations at all scales, which is critical to understanding how regional populations respond to landscape processes such as habitat loss and fragmentation. Therefore, because it is spatially explicit and directly addresses population growth and viability, this approach provides a valuable foundation to planning conservation strategies, offering the ability to identify the most salient risks to viability and explore ways to address them.     

Habitat selection by amphibians across an agricultural land-heathland transect in Britain

Potential and actual breeding sites for amphibians have been investigated in an area encompassing agricultural land and uncultivated heathland. pH and conductivity measurements have been made together with species records and some other aspects of habitat structure noted. Ponds around the farmland-heathland interface were especially well used by amphibians; there had been major losses of ponds in the agricultural zone, while those further out on the heathland were usually highly oligotrophic and capable of supporting only Triturus helveticus at most. Populations of the newts T. helveticus and T. vulgaris were composed of significantly smaller individuals in heathland ponds than in other sites. Implications of this study for conservation are discussed.     

Waterfowl-habitat associations during winter in an urban North Atlantic estuary

Coastal habitats near urban centres in North Atlantic estuaries often support substantial numbers of wintering waterfowl, but little is known of the effects of landscape setting and urbanisation on habitat use. We conducted surveys of waterfowl at 32 wintering sites in Narragansett Bay, Rhode Island, to identify characteristics that may influence habitat use. Sites were chosen along a gradient of urbanisation and reflected the dominant habitat types used by waterfowl in the Bay. Mean waterfowl abundance was 206.7 ± 209.5 birds per site, and sites in the inner part of the estuary had higher overall waterfowl abundances (r² = 0.40, p = 0.021). Species richness ranged from 3.2 to 13.0 and decreased with increasing hunting activity (r² = 0.36, p = 0.040). Hunting activity and habitat characteristics (e.g., latitude, shoreline configuration, prey density) explained 13-27% of the variation in waterfowl abundance and species richness among sites, but landscape characteristics (e.g., surrounding residential development, vegetated land, or wetland surrounding the sites and the extent of wetland edge) explained an additional 1-26%. The landscape characteristics extent of adjacent residential development and vegetated upland were the most common variables entering into the models; most species were more abundant at sites with more adjacent vegetated upland and less adjacent residential development. Our results suggest that landscape setting may be influencing the distribution of wintering waterfowl, and should be considered when developing strategies for the conservation for these species in urban North Atlantic estuaries.     

Beyond occurrence: Body condition and stress hormone as integrative indicators of habitat availability and fragmentation in the common toad

Availability and fragmentation of habitat are today identified as key determinants of population maintenance. Disentangling their relative effects is of crucial importance to adequately manage landscapes. However, the classical use of occurrence or abundance data as proxy to assess the responses of populations could be insufficient to detect less drastic impacts than short-term population extinction. We evaluated the effects of both habitat availability and fragmentation at three spatial scales on both the occurrence and two “physiological state” indicators (body condition and level of stress hormone) reflecting the physical state of common toads (Bufo bufo). Our study showed that occurrence was negatively affected only by habitat availability at the largest spatial scale whereas the both physiological state indicators studied at the population scale are significantly altered by both habitat availability and fragmentation at the finest spatial scale. Results obtained with occurrence and physiological state approaches substantially diverge, which highlights the need to also investigate proximal processes to deeply understand how populations are threatened by landscape modifications. The use of physiological state indicators, particularly of body condition, powerful and easy to obtain, could be particularly relevant to detect early warnings of population decline allowing a management before extinction. Only a complete investigation of the potential impacts of landscape on the different population processes could offer a realistic picture of the requirements of populations to avoid drastic alterations.     

Habitats of the British amphibians (4): Agricultural lowlands and a general discussion of requirements

Ponds on about 80 km² of farmland in Sussex were investigated with regard to breeding amphibians. The survey covered five different geological strata and included 60 ponds (out of a total of more than 200) marked on 1:25000 ordnance maps. Eighteen of these ponds were found on inspection not to exist; the remainder were characterised with respect to surface area, depth, pH, ionic score, aquatic vegetation, fish fauna and surrounding terrestrial habitats as well as for amphibian species. 14 pools contained amphibians; Triturus vulgaris was the most widespread (9 ponds) closely followed by T. helveticus (8 ponds). T. cristatus occurred at 5 sites, Rana temporaria at 2 and Bufo bufo not at all. The 2 frog sites were very shallow pools on pasture/woodland interfaces; the ideal newt pond had no fish, was 0·5–1·0 m deep and < 200 m² in surface area with 5–50% aquatic vegetation cover and a low ionic score (< 400 parts/10⁶). Callitriche-containing ponds were particularly favoured, and with terrestrial habitat there was a requirement for a scrub or woodland component.     

Autumn-sowing of cereals reduces breeding bird numbers in a heterogeneous agricultural landscape

The switch from spring-sown to autumn-sown cereals and the loss of habitat heterogeneity are often suggested to be key drivers of breeding bird decline on arable farmland. Yet, both factors are interlinked and it remains uncertain whether autumn-sown cereals reduce breeding bird numbers also in the structurally complex arable farmland of northern Europe. We tested whether autumn-sowing of cereals at both local and landscape scales affected the breeding bird community in a heterogeneous agricultural landscape of south-central Sweden. Rotation between sowing types was used as a semi-experiment based on 34 spring- vs. 41 autumn-sown cereal plots centred on infield non-crop islands of similar structure, size and surroundings. Species richness and territory abundance of ground-foraging species were significantly lower in autumn- than in spring-sown cereal plots both in the crop fields and the infield non-crop islands during the breeding season. No such effect was observed among foliage gleaning birds. Species richness in spring-sown cereal plots was less the more autumn-sown crops in the surrounding landscape within a 500 m radius. Average skylark densities did not differ between autumn- and spring-sown cereal plots because habitat preferences changed; densities declined in autumn-sown cereals during the growing season whereas they increased on spring-sown fields which had shorter swards throughout the breeding season. Our results indicate that negative effects of autumn-sown crops on breeding bird numbers spill over into both neighbouring non-crop and crop habitats. We conclude that agri-environmental schemes should place more emphasis on facilitating the value of the cropped area of fields as a foraging and nesting habitat. The retention of various non-crop habitats alone may not provide sufficient food close to nest sites for farmland birds that rely on crop fields for foraging.     

The relative importance of patch habitat quality and landscape attributes on a declining steppe-bird metapopulation

Metapopulation theory is one of the most popular approaches to identify the factors affecting the spatial and temporal dynamics of populations in fragmented habitat networks. Habitat quality, patch area and isolation are mainly focused on when analyzing distribution patterns in fragmented landscapes. The effects of landscape heterogeneity in the non-occupied matrix, however, have been largely neglected. Here, we determined the relative importance of patch quality and landscape attributes on the occurrence, density and extinction of the Dupont’s lark (Chersophilus duponti), an endangered steppe passerine whose habitat has been extremely reduced to highly isolated and fragmented patches embedded in a mainly unsuitable landscape matrix. Habitat patch quality, measured in terms of vegetation structure, grazing pressure, arthropod availability, predator abundance, and inter-specific competition, did not affect occurrence, density or extinction. At the landscape scale, however, the species’ occurrence was principally determined by the interactions among patch size, geographic isolation and landscape matrix. Isolation had the main independent contribution to explaining the probability of occurrence, followed by landscape matrix composition and patch size. The species’ density was negatively correlated to patch size, suggesting crowding effects in small fragments, while extinction events were exclusively related to isolation. Our findings suggest that landscape rather than local population characteristics are crucial in determining the patterns of distribution and abundance of non-equilibrium populations in highly fragmented habitat networks. Consequently, conservation measures for these species should simultaneously involve patch size, isolation and landscape matrix and apply to the entire metapopulation rather than to particular patches.