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A long‐standing hypothesis in biogeography is that a species’ abundance is highest at the centre of its geographical or environmental space and decreases toward the edges. Several studies tested this hypothesis and provided mixed results and overall weak support to the theory. Most studies, however, are affected by several limitations related to the sample size, the comparability among abundance measures, the definition of species geographic range and corresponding environmental space, and the proxy variables used to represent centrality/marginality gradients. Here we test the abundant‐centre hypothesis on 108 bird and mammal species and embrace the plural nature of the hypothesis by considering 9 geographic and ecological centrality/marginality measures. We analyse the species‐specific effect sizes using a meta‐analytical approach, and test whether the support for the hypothesis is mediated by species dispersal abilities, and the geographic and environmental coverage of the data. The summary effect sizes estimated for the 9 measures are largely inconsistent with the theoretical expectations and show a significant amount of residual heterogeneity. Variables such as dispersal distance, geographic and environmental coverage of the data, appear important in explaining the variation observed between different species, but the results are contrary to those originally hypothesized, and inconsistent across centrality/marginality measures and the datasets used. We show that addressing common pitfalls in previous studies does not provide more support to the abundant‐centre hypothesis, with support being very dependent on the centrality/marginality measure tested, the geographic extent considered for the test, and geographic and environmental coverage of the data. The abundant‐centre hypothesis so far remains an appealing speculation with little and variable empirical support.

Macroecologists traditionally emphasized the role of environmental variables for predicting species distribution and abundance at large scale. While biotic factors have been increasingly recognized as important at macroecological scales, producing valuable biotic variables remains challenging and rarely tested. Capitalizing on the wealth of population density estimates available for African savannah ungulates, here we modeled species average population density at 100 × 100 km as a function of both environmental variables and proxies of biotic interactions (competition and predation) and estimated their relative contribution. We fitted a linear mixed effect model on 1043 population density estimates for 63 species of ungulates using Bayesian inference and estimated the percentage of total variance explained by environmental, anthropogenic, and biotic interactions variables. Environmental and anthropogenic variables were the main drivers of ungulate population density, with NDVI, Distance to permanent water bodies and Human population density showing the highest contribution to the variance. Nonetheless, biotic interactions altogether contributed to a quarter of the variance explained, with predation and competition having a negative effect on species density. Despite the limitations of modelling biotic interactions in macroecological studies, proxies of biotic interactions can enhance our understanding of biological patterns at broad spatial scales, uncovering novel predictors as well as enhancing the predictive power of large-scale models.

Tropical Southeast (SE) Asia harbors extraordinary species richness and in its entirety comprises four of the Earth's 34 biodiversity hotspots. Here, we examine the assembly of the SE Asian biota through time and space. We conduct meta-analyses of geological, climatic, and biological (including 61 phylogenetic) data sets to test which areas have been the sources of long-term biological diversity in SE Asia, particularly in the pre-Miocene, Miocene, and Plio-Pleistocene, and whether the respective biota have been dominated by in situ diversification, immigration and/or emigration, or equilibrium dynamics. We identify Borneo and Indochina, in particular, as major \"evolutionary hotspots\" for a diverse range of fauna and flora. Although most of the region's biodiversity is a result of both the accumulation of immigrants and in situ diversification, within-area diversification and subsequent emigration have been the predominant signals characterizing Indochina and Borneo's biota since at least the early Miocene. In contrast, colonization events are comparatively rare from younger volcanically active emergent islands such as Java, which show increased levels of immigration events. Few dispersal events were observed across the major biogeographic barrier of Wallace's Line. Accelerated efforts to conserve Borneo's flora and fauna in particular, currently housing the highest levels of SE Asian plant and mammal species richness, are critically required.

The European Union has made extensive biodiversity conservation efforts with the Habitats and Birds Directives and with the establishment of the Natura 2000 network of protected areas, one of the largest networks of conservation areas worldwide. We performed a gap analysis of the entire Natura 2000 system plus national protected areas and all terrestrial vertebrates (freshwater fish excluded). We also evaluated the level of connectivity of both systems, providing therefore a first estimate of the functionality of the Natura 2000 system as an effective network of protected areas. Together national protected areas and the Natura 2000 network covered more than one‐third of the European Union. National protected areas did not offer protection to 13 total gap species (i.e., species not covered by any protected area) or to almost 300 partial gap species (i.e., species whose representation target is not met). Together the Natura 2000 network and national protected areas left 1 total gap species and 121 partial gap species unprotected. The terrestrial vertebrates listed in the Habitats and Birds Directives were relatively well covered (especially birds), and overall connectivity was improved considerably by Natura 2000 sites that act as stepping stones between national protected areas. Overall, we found that the Natura 2000 network represents at continental level an important network of protected areas that acts as a good complement to existing national protected areas. However, a number of problems remain that are mainly linked to the criteria used to list the species in the Habitats and Birds Directives. The European Commission initiated in 2014 a process aimed at assessing the importance of the Birds and Habitats Directives for biodiversity conservation. Our results contribute to this assessment and suggest the system is largely effective for terrestrial vertebrates but would benefit from further updating of the species lists and field management.

Aim: Species distribution models (SDMs) based on current species ranges underestimate the potential distribution when projected in time and/or space. A multitemporal model calibration approach has been suggested as an alternative, and we evaluate this using 13,000 years of data. Location: Europe. Methods: We used fossil-based records of presence for Picea abies, Abies alba and Fagus sylvatica and six climatic variables for the period 13,000 to 1000 yr BP. To measure the contribution of each 1000-year time step to the total niche of each species (the niche measured by pooling all the data), we employed a principal components analysis (PCA) calibrated with data over the entire range of possible climates. Then we projected both the total niche and the partial niches from single time frames into the PCA space, and tested if the partial niches were more similar to the total niche than random. Using an ensemble forecasting approach, we calibrated SDMs for each time frame and for the pooled database. We projected each model to current climate and evaluated the results against current pollen data. We also projected all models into the future. Results: Niche similarity between the partial and the total-SDMs was almost always statistically significant and increased through time. SDMs calibrated from single time frames gave different results when projected to current climate, providing evidence of a change in the species realized niches through time. Moreover, they predicted limited climate suitability when compared with the total-SDMs. The same results were obtained when projected to future climates. Main conclusions: The realized climatic niche of species differed for current and future climates when SDMs were calibrated considering different past climates. Building the niche as an ensemble through time represents a way forward to a better understanding of a species' range and its ecology in a changing climate.

Alternative land uses make different contributions to the conservation of biodiversity and have different implementation and management costs. Conservation planning analyses to date have generally assumed that land is either protected or unprotected and that the unprotected portion does not contribute to conservation goals. We develop and apply a new planning approach that explicitly accounts for the contribution of a diverse range of land uses to achieving conservation goals. Using East Kalimantan (Indonesian Borneo) as a case study, we prioritize investments in alternative conservation strategies and account for the relative contribution of land uses ranging from production forest to well-managed protected areas. We employ data on the distribution of mammals and assign species-specific conservation targets to achieve equitable protection by accounting for life history characteristics and home range sizes. The relative sensitivity of each species to forest degradation determines the contribution of each land use to achieving targets. We compare the cost effectiveness of our approach to a plan that considers only the contribution of protected areas to biodiversity conservation, and to a plan that assumes that the cost of conservation is represented by only the opportunity costs of conservation to the timber industry. Our preliminary results will require further development and substantial stakeholder engagement prior to implementation; nonetheless we reveal that, by accounting for the contribution of unprotected land, we can obtain more refined estimates of the costs of conservation. Using traditional planning approaches would overestimate the cost of achieving the conservation targets by an order of magnitude. Our approach reveals not only where to invest, but which strategies to invest in, in order to effectively and efficiently conserve biodiversity.

Aim Gap analysis measures the percentage of protected species distribution and generally compares it to a representation target (i.e. minimum area to be protected). The results are used to identify species that need further protection, providing a quantitative baseline to address a possible expansion of a given protected area (PA) systems. However, the achievement of the same representation target may have different implications in terms of species persistence depending on population spatial structure and conservation needs. The aim was to investigate to what extent and why gap analysis may provide inequitable assessments of species protection. Location Europe. Methods We performed three gap analyses on 27 European species of carnivores and ungulates, measuring the level of protection according to three different types of distribution data: geographical ranges, habitat suitability models and habitat suitability models that incorporate the potential spatial structuring in populations within PAs. Results The estimated degree of species protection depends on the distribution proxy and the target adopted. When the analyses are based on areas able to support viable populations (irrespective of how these areas are quantified), the perceived relative protection of different species changes considerably. The ability of different species to persist in PA systems mostly depends on their population density and dispersal abilities, as well as the interaction between these two features, which eventually determines the number and relative size of the populations. Main conclusions The achievement of the same representation target for different species may imply protecting different numbers of individuals in populations having different spatial structures and may consequently lead to different probabilities of persistence across species. If species spatial structuring is disregarded, gap analysis may thus lead to inequitable assessments of PA coverage.

The Mediterranean basin is one of the most important biodiversity hotspots. However, only 5% of its original vegetation is still in place, and the landscape has been managed and transformed by humans for at least the last two millennia. In the last century the mechanization of agriculture and the over-use of semi-natural habitats have influenced the region even more than before, with huge consequences, especially on islands. Sardinia is the second largest island in the Mediterranean basin, and it has been considered for long as a semi-natural area with an economy based on traditional agroforestry and pastoral practices. Considering four maps covering Sardinia and ranging from 1935 to 2007, we measured the rate of forest changes demonstrating a constant trend towards forest increase, and with a complete recovery of the total forest surface compared to the late 1800s. The traditional agroforestry practices decrease in time due to socio-economic reasons, with deeper consequences for the mosaic of traditional agricultural areas and semi-natural habitats, as well as for the conservation of the unique biodiversity of Sardinia. Species typically linked to Mediterranean forests recovered and are recovering, while species linked to traditional semi-natural landscapes decreased, facing conservation problems. We suggest that the current challenges for biodiversity conservation in the island should be focused together with the agricultural policies towards the preservation and improvement of traditional open areas, even important in the history of the entire Mediterranean hotspot.

The Apennine brown bear (Ursus arctos marsicanus) survives today in a relict population of about 50 bears in the central Apennines, even though they have been long protected and habitat suitability at the landscape scale does not appear to be a limiting factor for population recovery. Multiple uses within the bear range may increase disturbance and chances of human-caused mortality, including wild boar hunting drives with dogs conducted in the fall and coinciding with hyperphagia in bears. Although wild boar hunting drives represent a very popular recreational activity throughout the central Apennines, this is a very invasive practice and is thought to exert both direct and indirect detrimental effects on bears. In order to foster the progressive abandonment of wild boar hunting drives in the bear range in favor of less impacting hunting methods, we developed a species distribution model (SDM) to identify areas of likely bear presence during hyperphagia. This SDM could represent the basis to develop a hunting zoning system useful to modulate wild boar hunting regimes according to the bear occurrence. Starting from a large dataset of bear occurrences collected from September to November (2005–2010) within the core distribution range of the bear (n = 5746 GPS- and VHF-telemetry locations on 25 adult and subadult bears, plus other signs of bear presence), we modeled the distribution of bears during hyperphagia and selected candidate models using second order corrected Akaike information criteria (AIC c). The final model included 16 environmental, topographic, and anthropogenic variables and was evaluated using the continuous Boyce index (0.91). By intersecting the bear occurrence model with a proxy of wild boar hunting intensity, we identified the areas where the banning of wild boar hunting drives represents a priority, and where less impacting hunting regimes are urgently needed. By discussing how such a model can be used to facilitate consensus toward alternative hunting management scenarios, we believe our approach can be extended to other small populations of bears, and of other species as well, that live in multiple-use landscapes and are in need of recovery.

A quasi-complete time series of biomass, maximum body size and spatial distribution was reconstructed for turbotPsetta maximaL. in the Kattegat-Skagerrak based on standardized research surveys extending back to 1925. Here we show that biomass has declined by about 86% over the time series, maximum body size has decreased by 20 cm and the northern component of the population has virtually vanished. These trends are likely to be underestimated due to the conservative approach we used by assuming a low level of ‘technological creep’ during the survey period, suggesting that the actual reduction in biomass might have been between 92 and 95%. Absence of trend in former analyses of data collected in the last 2 or 3 decades is dangerously misleading. This substantial difference in stock status, based on historical data, highlights the general importance of the historical perspective for managing natural resources.