We assess progress toward the protection of 50% of the terrestrial biosphere to address the species-extinction crisis and conserve a global ecological heritage for future generations. Using a map of Earth's 846 terrestrial ecoregions, we show that 98 ecoregions (12%) exceed Half Protected; 313 ecoregions (37%) fall short of Half Protected but have sufficient unaltered habitat remaining to reach the target; and 207 ecoregions (24%) are in peril, where an average of only 4% of natural habitat remains. We propose a Global Deal for Nature—a companion to the Paris Climate Deal—to promote increased habitat protection and restoration, national- and ecoregion-scale conservation strategies, and the empowerment of indigenous peoples to protect their sovereign lands. The goal of such an accord would be to protect half the terrestrial realm by 2050 to halt the extinction crisis while sustaining human livelihoods.

The Global Deal for Nature (GDN) is a time-bound, science-driven plan to save the diversity and abundance of life on Earth. Pairing the GDN and the Paris Climate Agreement would avoid catastrophic climate change, conserve species, and secure essential ecosystem services. New findings give urgency to this union: Less than half of the terrestrial realm is intact, yet conserving all native ecosystems—coupled with energy transition measures—will be required to remain below a 1.5°C rise in average global temperature. The GDN targets 30% of Earth to be formally protected and an additional 20% designated as climate stabilization areas, by 2030, to stay below 1.5°C. We highlight the 67% of terrestrial ecoregions that can meet 30% protection, thereby reducing extinction threats and carbon emissions from natural reservoirs. Freshwater and marine targets included here extend the GDN to all realms and provide a pathway to ensuring a more livable biosphere.

Global strategies to halt the dual crises of biodiversity loss and climate change are often formulated separately, even though they are interdependent and risk failure if pursued in isolation. The Global Safety Net maps how expanded nature conservation addresses both overarching threats. We identify 50% of the terrestrial realm that, if conserved, would reverse further biodiversity loss, prevent CO2 emissions from land conversion, and enhance natural carbon removal. This framework shows that, beyond the 15.1% land area currently protected, 35.3% of land area is needed to conserve additional sites of particular importance for biodiversity and stabilize the climate. Fifty ecoregions and 20 countries contribute disproportionately to proposed targets. Indigenous lands overlap extensively with the Global Safety Net. Conserving the Global Safety Net could support public health by reducing the potential for zoonotic diseases like COVID-19 from emerging in the future.

Wildlife populations in small, isolated reserves face genetic and demographic threats to their survival. To increase the probability of long-term persistence, biologists promote metapopulation management, in which breeding subpopulations are protected as source pools. Animals that disperse from the source pools increase the probability of persistence of the metapopulation across the greater landscape. We used a geographic information system (GIS)-based, cost-distance model to design a conservation landscape along the Himalayan foothills for managing a metapopulation of Asia's largest predator, the tiger (Panthera tigris). The model is based on data from 30 years of field research on tigers, recent satellite imagery, and a decade of buffer-zone restoration in this region. We used the model to (1) identify potential dispersal corridors for tigers; (2) identify strategic transit refuges; and (3) make recommendations for off-reserve land management and restoration to enhance the potential of corridors for tigers. This tool can aid the design of conservation landscapes for other endangered, wide-ranging species in human-dominated environments. Diseño de un Paisaje de Conservación para Tigres en Ambientes Dominados por HumanosResumen: La supervivencia de poblaciones de vida silvestre en reservas pequeñas y aisladas enfrenta amenazas genéticas y demográficas. Para incrementar la probabilidad de persistencia a largo plazo, los biólogos promueven el manejo metapoblacional, en el que las subpoblaciones reproductivas son protegidas como fuentes. Los animales que se dispersan desde la fuente incrementan la probabilidad de persistencia de la metapoblación en el paisaje extendido. Utilizamos un modelo de costo-distancia, basado en SIG, para diseñar un paisaje de conservación en las estribaciones de los Himalaya para manejar una metapoblación del mayor depredador de Asia, el tigre (Panthera tigris). El modelo se basa en datos de 30 años de investigaciones de campo, imágenes de satélite recientes y una década de restauración de la zona de amortiguamiento en esta región. Utilizamos el modelo para (1) identificar potenciales corredores de dispersión para tigres; (2) identificar refugios de tránsito estratégicos y (3) hacer recomendaciones para el manejo y la restauración de tierras afuera de la reserva para promover el potencial de los corredores para tigres. Esta herramienta puede auxiliar en el diseño de paisajes de conservación para otras especies en peligro y de amplio rango de distribución en ambientes dominados por humanos.

Most bears are opportunistic omnivores; their diets consist of fruits, other vegetative material, and in lesser amounts, mammals, fishes, and insects. Sloth bears (Melursus ursinus) are the only species of ursid specifically adapted to feed on insects, especially termites and ants, although they also feed on fruits when available. We studied diets of sloth bears in Royal Chitwan National Park, Nepal, where fruits are available for ca. 4 months (MayAugust) and access to colonies of termites is reduced in lowlands that are flooded during the fruiting season. We analyzed feces and observed sloth bears foraging to investigate their responses to changes in availability of food. Diets of sloth bears were dominated by insects (>90%), especially termites (2:50%), from September through April, but they relied heavily on fruits from May through August. Seasonal movements between lowland and upland habitats seemed to be prompted mainly by availability of termites. Termites were more dominant in the diets of sloth bears in our study than in a study conducted 20 years ago in Royal Chitwan National Park and in studies in India. The dietary shift of sloth bears in Royal Chitwan National Park may have been related to changes in habitat conditions associated with relocation of people out of the Park. It appears that sloth bears, like other bears but unlike other myrmecophagous mammals, can adapt their diet to changing food conditions.

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Real-time forest monitoring technologies could help track changes in tiger populations.