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Pangolins are globally threatened by unsustainable hunting for local use and illegal international trade, plus habitat loss. In Benin (West Africa), white‐bellied and giant pangolins have experienced a contraction in their distribution areas and population decline during the last two decades. To better understand the factors underlying declines in these species, we investigated extirpation rates of populations over the last 20 years. Because pangolins are elusive species difficult to monitor by standard methods, the status of populations has been assessed through a local ecological knowledge (LEK) approach. We collected information on persistence or extirpation status of pangolins from 156 localities. A binomial model was built to predict population persistence probability as a function of past and ongoing landscape changes, initial abundance (1998), human pressures, and density of the protected area network. The LEK‐based model was highly accurate (97% correct classification rate) in predicting the presence of white‐bellied pangolin in 52 localities where its presence has been confirmed independently. According to model outputs, persistence probability of pangolins is positively related to distance to main road, initial population abundance, and negatively related to deforestation, shrinkage of favorable habitat, and distance to protected areas. When those factors are controlled for, the white‐bellied pangolin has a higher probability of persistence than the giant pangolin. Even assuming no further habitat change, the distribution area of the white‐bellied pangolin is predicted to keep decreasing against an unavoidable extinction of the giant pangolin in Benin in the next two decades. Besides validating the usefulness of LEK as a population assessment method, this study emphasizes that, despite a demonstrated positive effect of protected areas, the current situation is not sustainable for pangolins and calls for urgent conservation actions to stop or reduce overhunting. [ABSTRACT FROM AUTHOR]

Copyright of Methods in Ecology & Evolution is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Aim: Assessing the threat status of declining but yet widespread species poses a challenge to applied ecologists. Previous studies using a common metric to describe the spatial aggregation of occurrences across multiple scales, the fractal dimension Dij, have suggested that species' distributional trends may be deduced from readily understandable spatial patterns: Expanding species are expected to show more aggregated spatial distributions (higher value of Dij) than declining species (lower value of Dij). Here, we revisited these predictions using a large‐scale empirical dataset on Finnish butterflies. Location: Finland. Methods: For each butterfly species (n = 97) and across three spatial scales (grid squares of 10 km, 50 km and 100 km), we calculated the area of occupancy (AOOi) as the sum of occupied grid squares. We employed values of AOOi to derive the Dij for each butterfly species. We then used these metrics to compare the changes in spatial patterns of distribution (∆AOOi and ∆Dij) between two time periods, 2000–2002 and 2009–2011. Results: Majority of the studied butterfly species showed declining areas of occupancy (at the scale of 10 km, ∆AOO10) and fractal dimensions (across the scales from 10 km to 100 km, ∆D10–100) between the two study periods. In contrast to predictions, AOO10 and D10–100 showed negative impacts on the ∆AOO10, an observation that may be explained by the high proportion of declining species in our data. Butterfly species with the greatest fractal dimensions at regional scales (D10–100) in the years 2000–2002 showed both positive long‐term distributional trends and most notable northern recent range limit shifts. Main conclusions: Our results were in most cases congruent with the prediction of higher fractal dimension values in expanding compared to declining species. As a novel observation, many butterflies expanded northwards in spite of their occurrences getting simultaneously more scattered, particularly in southern Finland. [ABSTRACT FROM AUTHOR]

Aim Stochastic threats such as disease outbreak, pollution events, fire, tsunami and drought can cause rapid species extinction and ecosystem collapse. The ability of a species or ecosystem to persist after a stochastic threat is strongly related to the extent and spatial pattern of its geographical distribution. Consequently, protocols for assessing risks to biodiversity typically include geographic range size criteria for assessing risks from stochastic threats. However, owing in part to the rarity of such events in nature, the metrics for assessing risk categories have never been tested. In this study, we investigate the performance of alternative range size metrics, including the two most widely used, extent of occurrence ( EOO) and area of occupancy ( AOO), as predictors of ecosystem collapse in landscapes subject to stochastic threats. Methods We developed a spatially explicit stochastic simulation model to investigate the impacts of four threat types on a dataset of 1350 simulated geographic distributions of varying pattern and size. We empirically estimated collapse probability in response to each threat type and evaluated the ability of a set of spatial predictors to predict risk. Results The probability of ecosystem collapse increased rapidly as range size declined. While AOO and EOO were the most important predictors of collapse risk for the three spatially explicit threats included in our model (circle, swipe and cluster), core area, patch density and mean patch size were better predictors for edge effect threats. Main conclusions Our study is the first to quantitatively assess the range size metrics employed in biodiversity risk assessment protocols. We show that the current methods for measuring range size are the best spatial metrics for estimating risks from stochastic threats. Our simulation framework delivers an objective assessment of the performance of hitherto untested but widely used measures of geographic range size for risk assessment. [ABSTRACT FROM AUTHOR]

Areas of endemism are conservation priorities and indicators of biogeographical processes, representing concentrations of range-restricted biodiversity. While the term endemism describes geographical range restriction, the technical definition has often been re-worked. Categorical definitions are increasingly replaced by weighting of species according to range sizes. In various contexts, range sizes have been estimated by the number of occupied map grid cells, the latitudinal or longitudinal range of point locations, or the area of a polygon surrounding point locations. Existing implementations of weighted endemism use the number of occupied grid cells to estimate range. However, this represents area of occupancy ( AOO), not extent of occurrence ( EOO)., We developed endemism calculations that include strictly geographical (georeferenced) interpretations of range ('span' and 'area'), and compared them to cell frequency-based measures. We compared species weights and endemism scores for 330 004 records of 3083 vascular plant species in 14 328 plots (Biological Survey of South Australia). We provide a self-contained R function that calculates endemism using alternative range weights and integrates point data with automatically generated rasters. A parallel function tests for deviance from the expected (null) distribution, given observed species richness (nonparametric significance test; outlier metrics)., Species range weights based on grid cell frequency ( AOO) versus georeferenced 'span' and 'area' ( EOO) are conceptually different and were poorly correlated for the same data set, resulting in differences in the classification of grid cells as outliers from expected endemism. For example, the correlation (Kendall's τ) between endemism based on geographical 'span' and cell frequency was just 0·57, when partialling out the influence of species richness, potentially leading to contrasting conservation priorities over 8% or 46 000 km2 of the state of South Australia., Weighting endemism by georeferenced range estimates provides an alternative approach that more explicitly highlights restriction in EOO, generates differences in endemism metrics and requires only georeferenced species records. This approach need not replace existing implementations, but provides an alternative measure of range-restricted biodiversity. The functions provide efficient calculation of species ranges (with or without geographical outlier exclusion) and weighted endemism with novel implementation of significance tests and outlier detection, in the R environment. [ABSTRACT FROM AUTHOR]

ABSTRACT Aim Estimates of geographic range size derived from natural history museum specimens are probably biased for many species. We aim to determine how bias in these estimates relates to range size. Location We conducted computer simulations based on herbarium specimen records from localities ranging from the southern United States to northern Argentina. Methods We used theory on the sampling distribution of the mean and variance to develop working hypotheses about how range size, defined as area of occupancy (AOO), was related to the inter-specific distribution of: (1) mean collection effort per area across the range of a species (MC); (2) variance in collection effort per area across the range of a species (VC); and (3) proportional bias in AOO estimates (PBias: the difference between the expected value of the estimate of AOO and true AOO, divided by true AOO). We tested predictions from these hypotheses using computer simulations based on a dataset of more than 29,000 herbarium specimen records documenting occurrences of 377 plant species in the tribe Bignonieae (Bignoniaceae). Results The working hypotheses predicted that the mean of the inter-specific distribution of MC, VC and PBias were independent of AOO, but that the respective variance and skewness decreased with increasing AOO. Computer simulations supported all but one prediction: the variance of the inter-specific distribution of VC did not decrease with increasing AOO. Main conclusions Our results suggest that, despite an invariant mean, the dispersion and symmetry of the inter-specific distribution of PBias decreases as AOO increases. As AOO increased, range size was less severely underestimated for a large proportion of simulated species. However, as AOO increased, range size estimates having extremely low bias were less common. [ABSTRACT FROM AUTHOR]

Underpinning the International Union for Conservation of Nature (IUCN) Red List is the assessment of extinction risk as determined by the size and degree of loss of populations. The IUCN system lists a species as Critically Endangered, Endangered, or Vulnerable if its population size declines 80%, 50%, or 30% within a given time frame. However, effective implementation of the system faces substantial challenges and uncertainty because geographic scale data on population size and long-term dynamics are scarce. I develop a model to quantify extinction risk using a measure based on a species' distribution, a much more readily obtained quantity. The model calculates the loss of the area of occupancy that is equivalent to the loss of a given proportion of a population. It is a very simple yet general model that has no free parameters and is independent of scale. The model predicted well the distributions of 302 tree species at a local scale and the distributions of 348 species of North American land birds. This area-based model provides a solution to the long-standing problem for IUCN assessments of lack of data on population sizes, and thus it will contribute to facilitating the quantification of extinction risk worldwide. [ABSTRACT FROM AUTHOR]

1. Geographic range size and how it changes through time is one of the fundamental ecological and evolutionary characteristics of a species, and a strong predictor of extinction risk. However, the measurement of range size remains a substantial challenge. Indeed, there is significant confusion in the literature as to how this should be done, particularly in the context of the distinction between the fundamentally different concepts of extent of occurrence (EOO) and area of occupancy (AOO), and the use of these quantities, including in assessments of the threat status of species. 2. Here we review the different approaches to determining the geographic distributions of species, the measurement of their range sizes, the relationships between the two, and other difficulties posed by range size measurement (especially those of range discontinuities when measuring EOO, and spatial scale when measuring AOO). 3. We argue that it is important to (i) distinguish the estimation of the distribution of a species from the measurement of its geographic range size; (ii) treat measures of EOO and AOO as serving different purposes, rather than regarding them as more or less accurate ways of measuring range size; and (iii) measure EOO including discontinuities in habitat or occupancy. 4. Synthesis and applications. With the availability and collation of extensive data sets on species occurrences, a rapidly increasing number of studies are investigating geographic range size, and particularly how various measures of range size predict macroecological patterns and inform assessments of the conservation status of species and areas. The distinction between EOO and AOO is becoming blurred in many contexts, but most particularly in that of threatened species assessments for Red Listing. Continued progress in these fields demands greater clarity in the meaning and derivation of measures of geographic range size. The two principal measures serve different purposes, and should not be regarded as alternatives that simply differ in accuracy. [ABSTRACT FROM AUTHOR]

Copyright of Conservation Biology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Aim To investigate whether six plant life-history traits that have been related to colonization ability at local scales are also related to the geographical range characteristics of 273 forest plant species. Location Continental western Europe, five countries in particular: France, Luxemburg, Belgium, the Netherlands and Germany. The region is situated between 42° and 55°N and 5°W and 15°E and has a summed total area of 971,404 km2. Methods Distribution data were compiled from five national data bases and converted to a 10′ grid. Life-history traits were taken from existing compilations of autecological information of European species. The spatial arrangement of occupied grid cells was investigated using Ripley's K. Cross-species correlations and phylogenetically independent contrasts were used to investigate the relationships between plant life-history traits and three range characteristics: area of occupancy, latitudinal extent and centroid latitude. Results For herbaceous species, seed dispersal mode, seed production and seed bank longevity exhibited significant associations with geographical range characteristics, including area of occupancy. Woody plant species exhibited fewer significant associations, although maximum height was positively associated with range centroid latitude within the study area. Furthermore, the ranges of species with limited dispersal ability were found to be more clustered than the ranges of species with morphological adaptations for long-distance seed dispersal. Main conclusions For western European forest plant species, life-history traits that are related to colonization ability at local scales are associated with variation in large-scale geographical range characteristics. This finding implies that the distributions of some forest plant species in the study area may be limited by seed dispersal and colonization capacity rather than climate or other environmental factors. [ABSTRACT FROM AUTHOR]

1 The distribution patterns of 391 rare and scarce British plants (species recorded in 100 or fewer 10 × 10 km squares) were characterized by their distributional area (area of occupancy at 1-km scale: AOO1) and levels of aggregation (as reflected in fractal dimensions measured across two scales: D1−10 and D10−100). 2 Eighteen plant traits were tested for relationships to AOO, and to fractal dimension while controlling for AOO. These included both directly heritable traits (e.g. life-form) and emergent properties that are, at most, indirectly heritable (e.g. typical local density). The latter set included an index of net distributional change and an index of range dynamism. 3 Only two traits, habitat preference and local abundance, were significantly related to AOO1, but about half were associated with fractal dimension. 4 Relatively aggregated fine-scale distributions (high D1−10) were related to high local abundance, lack of specialized, long-distance dispersal mechanisms, habitat preference and an increasing range size with relatively few local extinctions (i.e. a positive index of change with low dynamism). 5 Relatively aggregated coarse-scale distributions (high D10−100) were related to the use of insect pollinators, obligate outcrossing, habitat preference and relatively stable ranges (low dynamism). 6 Multivariate analyses of subsets of conceptually related variables showed that few variables interacted to affect distributional variables. 7 A highly significant negative relationship between dynamism and fractal dimension appears to be driven primarily by high rates of local extinction, leading to relatively scattered, diffuse range structures. Furthermore, it suggests that recent population trends may be inferred from snapshots of contemporary distribution patterns. 8 The role and interpretation of phylogenetically informed analyses in studies such as this are debatable. However, we found similar relationships in both phylogenetically informed and conventional analyses for all variables except pollination vector (a strongly conserved trait). 9 The spatial pattern of plant species distributions is associated with a range of ecological traits, particularly those describing past changes in distribution. The analysis of distribution patterns therefore has the potential to inform future conservation effort. [ABSTRACT FROM AUTHOR]

The invasion process can be divided into several phases. We consider invasion patterns related to two aspects of the invasion process: the spread of a species in Germany as counted by the number of occupied grid cells, and the degree of naturalization in Germany (i.e. whether a plant species is exclusively naturalized in human-made habitats or also in (semi-)natural habitats). Although in Germany the area of natural habitats is smaller than that of human-made habitats, the area of occupancy of the respective alien plant species is the opposite. We tested whether both patterns could be explained by niche-breadth variables, namely the number of inhabited habitat types, and vegetation formations, the range of human impact levels, the number of inhabited continents, the number of inhabited floristic zones (climatic zones), and the amplitude of oceanity. Tests were conducted across species and across phylogenetically-independent contrasts, using generalized linear models, in particular, hierarchical partitioning. The number of occupied grid cells could be explained by niche-breadth variables, especially by number of habitats, number of formations, and amplitude of oceanity. Contrary to our expectations, none of these variables could explain the degree of naturalization in cross-species analyses, and amplitude of oceanity is the only stably significant variable that explains the degree of naturalization when analysing phylogenetically-independent contrasts. We conclude that the degree of naturalization is probably independent from niche breadth, and that properties of a larger area of occupancy, i.e. sample size (or propagule pressure), could be responsible for this pattern. [ABSTRACT FROM AUTHOR]