Pollinating species are in decline globally, with land use an important driver. However, most of the evidence on which these claims are made is patchy, based on studies with low taxonomic and geographic representativeness. Here, we model the effect of land-use type and intensity on global pollinator biodiversity, using a local-scale database covering 303 studies, 12,170 sites, and 4502 pollinating species. Relative to a primary vegetation baseline, we show that low levels of intensity can have beneficial effects on pollinator biodiversity. Within most anthropogenic land-use types however, increasing intensity is associated with significant reductions, particularly in urban (43% richness and 62% abundance reduction compared to the least intensive urban sites), and pasture (75% abundance reduction) areas. We further show that on cropland, the strongly negative response to intensity is restricted to tropical areas, and that the direction and magnitude of response differs among taxonomic groups. Our findings confirm widespread effects of land-use intensity on pollinators, most significantly in the tropics, where land use is predicted to change rapidly.

Aim Local effects of ecosystem engineers on biodiversity can scale up to the landscape level, stressing the importance of ecological processes as determinants of species richness at larger spatial scales. In harsh environments, cushion plants often act as ecosystem engineers given their ability to buffer extreme abiotic conditions, thus providing unique and more favorable niches for the establishment of less stress‐tolerant plant species. We assessed if facilitation by cushion plants influences patterns of plant diversity at increasing spatial scales. Location Northern Patagonian Andes, Argentina. Methods Based on plant species records within and outside cushions, we compared plant diversity in the presence and absence of cushions at the community, mountain and regional scale. Specifically, observed and estimated numbers of species occurring in either cushion plants or in the surrounding open areas were compared with the species numbers of the open areas. Results The presence of cushion plants significantly increased species richness at all spatial levels analyzed. At the patch level, a higher number of species was recorded growing within cushion plants than in open area plots of similar size. Consistently, hypothetical communities lacking cushion plants showed significantly lower species richness than observed communities with cushion plants. These differences in species richness at patch and community scales increased with altitude, hence facilitation by cushion plants became more important at higher elevations. Moreover, according to asymptotic non‐parametric estimators, cushion plants could increase overall regional species richness up to 40%. Conclusions Our findings suggest that about one third of the high‐Andean flora of the region owes its presence to the existence of nursing plants, defying the view that abiotic factors alone are enough to fully determine species occurrences at large spatial scales. This study provides evidence that local‐scale ecological processes can be crucial in promoting and maintaining biodiversity at any spatial scale.

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