Aim It is widely accepted that biodiversity is influenced by both niche‐related and spatial processes from local to global scales. Their relative importance, however, is still disputed, and empirical tests are surprisingly scarce at the global scale. Here, we compare the importance of area (as a proxy for pure spatial processes) and environmental heterogeneity (as a proxy for niche‐related processes) for predicting native mammal species richness world‐wide and within biogeographical regions. Location Global. Time period We analyse a spatial snapshot of richness data collated by the International Union for Conservation of Nature. Major taxa studied All terrestrial mammal species, including possibly extinct species and species with uncertain presence. Methods We applied a spreading dye algorithm to analyse how native mammal species richness changes with area and environmental heterogeneity. As measures for environmental heterogeneity, we used elevation ranges and precipitation ranges, which are well‐known correlates of species richness. Results We found that environmental heterogeneity explained species richness relationships better than did area, suggesting that niche‐related processes are more prevalent than pure area effects at broad scales. Main conclusions Our results imply that niche‐related processes are essential to understand broad‐scale species–area relationships and that habitat diversity is more important than area alone for the protection of global biodiversity.

Urbanization affects pollinator diversity and plant–pollinator networks by changing resource availability locally and in the surrounding landscape. We experimentally established (N = 12) standardized plant communities in farmland, villages, and cities to identify the relative role of local and landscape effects on plant–pollinator communities along this urbanization gradient. We found that the number of flower visits by solitary bees, but not bumblebees, was highest in cities and lowest in farmland, with villages being intermediate, whereas syrphid flies exhibited lowest numbers in cities. Villages supported the richest pollinator communities, as they appeared to benefit from both farmland and city communities. Plant–pollinator network metrics such as robustness, interaction evenness, and interaction diversity decreased with increasing urbanization, although local plant richness increased toward urban areas. In conclusion, pollinator communities were most diverse and stable in farmland and village sites, despite the high plant richness in cities. The different composition of pollinator communities along the urbanization gradient suggests considering all three landscape types for conservation schemes.

No abstract

Bombus terrestris (L.