The PREDICTS project—Projecting Responses of Ecological Diversity In Changing Terrestrial Systems (www.predicts.org.uk)—has collated from published studies a large, reasonably representative database of comparable samples of biodiversity from multiple sites that differ in the nature or intensity of human impacts relating to land use. We have used this evidence base to develop global and regional statistical models of how local biodiversity responds to these measures. We describe and make freely available this 2016 release of the database, containing more than 3.2 million records sampled at over 26,000 locations and representing over 47,000 species. We outline how the database can help in answering a range of questions in ecology and conservation biology. To our knowledge, this is the largest and most geographically and taxonomically representative database of spatial comparisons of biodiversity that has been collated to date; it will be useful to researchers and international efforts wishing to model and understand the global status of biodiversity.

Wildfires are common natural perturbations in Mediterranean ecosystems. Their frequency and extent have changed in recent decades to become one of the main ecological problems for wildlife. The response of fauna to wildfires depends greatly on the life histories and biological traits of each species. Terrestrial gastropods have limited mobility, and their presence is restricted by the vegetal and abiotic characteristics of habitats. For this reason, they are expected to have a low ability to recolonize burned areas. We have explored their survivorship and recolonization patterns according to the crypticrefuge and fire-edge models in a Mediterranean protected area affected by a large fire in August 2003. The low number of species recorded at burned sites demonstrates the negative effects of a wildfire on the richness of gastropod assemblages 4 years after the perturbation. However, the total number of living individuals did not vary between burned and unburned areas, suggesting an after-fire shift in dominant species from woodland to open-space species. Forest species with wide European distributions dominated in unburned sites, whereas open-space species and xerophytic Mediterranean species were present at burned sites. These differences were evident even at the burned sites closest to the unburned forest, suggesting low recolonization rates from the fire edge. By contrast, the abundance of xerophilous species as well as isolated records of mesophilous species in the burned areas suggests the survival of small populations and further recuperation after fire following the cryptic-refuge model.

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Land-use change is considered the main disturbance in landscape structure and composition, directly affecting faunal distribution and species richness worldwide. Wildfires and natural reforestation alter habitat structure in terms of vegetation cover and also in soil composition and moisture; these processes hence trigger habitat transformations that act as opposing forces at small spatial scales. We have explored the contrasting effects of wildfires and natural reforestation on two land-snail species of the genus Xerocrassa, which are endemic in the western Mediterranean. Snails were sampled in pine and Holm oak forest, stony bare slopes and burnt sites. Both species followed a similar pattern: they were present in more than 75% of the stony bare slope sites and around 50% of the burnt sites, but were almost absent in Holm oak forests. The comparison of aerial photographs from 1956 and 2003 showed that stony bare slopes were significantly larger in 1956, this indicating that the natural reforestation might close these habitats, and consequently threaten the viability of the Xerocrassa populations. Given their limited mobility, the presence of Xerocrassa at burnt sites suggests that these species live in small and cryptic populations within the forest, surviving fire and expanding their distribution due to the appearance of adequate habitats. Our study shows that natural reforestation and fire play opposing roles in conserving Xerocrassa populations. The preservation of stony bare slopes as well as other open areas is a key management guideline to maintain landscape mosaics and help future conservation of species of open habitats such as these vulnerable endemic gastropods.