The extent to which humans facilitate zoonotic transmission of infectious diseases is unclear. Human encroachment into wildlife habitats as a consequence of expanding urbanization, cropland area and intensive animal farming is hypothesized to favour the emergence of zoonotic diseases. Here we analyse comprehensive, high-resolution datasets on forest cover, cropland distribution, livestock density, human population, human settlements, bat species' distribution and land-use changes in regions populated by Asian horseshoe bats (>28.5 million km 2 )-the species that most commonly carry severe acute respiratory syndrome (SARS)-related coronaviruses. We identify areas at risk of SARS-related coronavirus outbreaks, showing that areas in China populated by horseshoe bats exhibit higher forest fragmentation and concentrations of livestock and humans than other countries. Our findings indicate that human-livestock-wildlife interactions in China may form hotspots with the potential to increase SARS-related coronavirus transmission from animals to humans.

Global changes in response to human encroachment into natural habitats and carbon emissions are driving the biodiversity extinction crisis and increasing disease emergence risk. Host distributions are one critical component to identify areas at risk of viral spillover, and bats act as reservoirs of diverse viruses. We developed a reproducible ecological niche modelling pipeline for bat hosts of SARS-like viruses (subgenus Sarbecovirus ), given that several closely related viruses have been discovered and sarbecovirus–host interactions have gained attention since SARS-CoV-2 emergence. We assessed sampling biases and modelled current distributions of bats based on climate and landscape relationships and project future scenarios for host hotspots. The most important predictors of species distributions were temperature seasonality and cave availability. We identified concentrated host hotspots in Myanmar and projected range contractions for most species by 2100. Our projections indicate hotspots will shift east in Southeast Asia in locations greater than 2°C hotter in a fossil-fuelled development future. Hotspot shifts have implications for conservation and public health, as loss of population connectivity can lead to local extinctions, and remaining hotspots may concentrate near human populations.

Rising interest in large-scale afforestation and reforestation as a strategy for climate change mitigation has recently motivated research efforts aiming at the identification of areas suitable for the plantation of trees. An often-overlooked aspect of agroforestry projects for carbon sequestration is their impact on water resources. It is often unclear to what extent the establishment of forest vegetation would be limited by water availability, whether it would engender competition with other local water uses or induce water scarcity. Here we use global water models to study the hydrologic constraints and impacts of afforestation in tropical biomes. We find that 36% of total suitable and available afforestation areas are in areas where the rain alone can meet just up to the 40% of total plant water requirement. Planting trees will substantially increase water scarcity and possible dispossession (green water grab) especially in dryland regions of Africa and Oceania. Moreover, the combination of tree restoration and irrigation expansion to rainfed agricultural areas is expected to further exacerbate water scarcity, with about half of the global suitable areas for tree restoration experiencing water scarcity at least 7 months per year. Thus, the unavailability of water can overall limit climate change adaptation strategies. This article is part of the theme issue ‘Ecological complexity and the biosphere: the next 30 years’.

Global changes in response to human encroachment into natural habitats and carbon emissions are driving the biodiversity extinction crisis and increasing disease emergence risk. Host distributions are one critical component to identify areas at risk of spillover, and bats act as reservoirs of diverse viruses. We developed a reproducible ecological niche modelling pipeline for bat hosts of SARS-like viruses (subgenus Sarbecovirus), given that since SARS-CoV-2 emergence several closely-related viruses have been discovered and sarbecovirus-host interactions have gained attention. We assess sampling biases and model bats’ current distributions based on climate and landscape relationships and project future scenarios. The most important predictors of species distribution were temperature seasonality and cave availability. We identified concentrated host hotspots in Myanmar and projected range contractions for most species by 2100. Our projections indicate hotspots will shift east in Southeast Asia in >2 °C hotter locations in a fossil-fueled development future. Hotspot shifts have implications for conservation and public health, as loss of population connectivity can lead to local extinctions, and remaining hotspots may concentrate near human populations.

Coronavirus disease 2019 (COVID-19) and severe acute respiratory syndrome (SARS) causing coronaviruses are mostly discovered in Asian horseshoe bats. It is still unclear how ongoing land use changes may facilitate SARS-related coronavirus transmission to humans. Here we use a multivariate hotspot analysis of high-resolution land-use data to show that regions of China populated by horseshoe bats are hotspots of forest fragmentation, livestock and human density. We also identify areas susceptible to new hotspot emergence in response to moderate expansion of urbanization, livestock production, or forest disturbance, thereby highlighting regions vulnerable to SARS-CoV spillover under future land-use change. In China population growth and increasing meat consumption associated with urbanization and economic development have expanded the footprint of agriculture, leading to human encroachment in wildlife habitat and increased livestock density in areas adjacent to fragmented forests. The reduced distance between horseshoe-bats and humans elevates the risk for SARS-related coronavirus transmission to humans.Sentence summarizing manuscriptWildlife reservoirs for SARS-coronavirus-2 live in global hotspots of forest fragmentation, livestock, and human density in China