People have shaped most of terrestrial nature for at least 12,000 years

Abstract

Archaeological and paleoecological evidence shows that by 10,000 BCE, all human societies employed varying degrees of ecologically transformative land use practices, including burning, hunting, species propagation, domestication, cultivation, and others that have left long-term legacies across the terrestrial biosphere. Yet, a lingering paradigm among natural scientists, conservationists, and policymakers is that human transformation of terrestrial nature is mostly recent and inherently destructive. Here, we use the most up-to-date, spatially explicit global reconstruction of historical human populations and land use to show that this paradigm is likely wrong. Even 12,000 y ago, nearly three quarters of Earth's land was inhabited and therefore shaped by human societies, including more than 95% of temperate and 90% of tropical woodlands. Lands now characterized as "natural," "intact," and "wild" generally exhibit long histories of use, as do protected areas and Indigenous lands, and current global patterns of vertebrate species richness and key biodiversity areas are more strongly associated with past patterns of land use than with present ones in regional landscapes now characterized as natural. The current biodiversity crisis can seldom be explained by the loss of uninhabited wildlands, resulting instead from the appropriation, colonization, and intensifying use of the biodiverse cultural landscapes long shaped and sustained by prior societies. Recognizing this deep cultural connection with biodiversity will therefore be essential to resolve the crisis.

Keywords: Anthropocene; agriculture; conservation; extinction; hunter-gatherer.

Fig. 1.

Global changes in anthromes and populations 10,000 BCE to 2017 CE. (A) Anthrome map at 2017 CE (Eckert IV projection). (B) Global changes in anthrome areas, with population changes indicated by red line. Anthromes are classified using population densities and dominant intensive land use. Wildlands are defined by zero population and no intensive land use (urban + crops + grazing), Cultured anthromes have low populations and <20% intensive use, and Intensive anthromes are ≥20% intensive. Cultured and Intensive anthromes are further stratified by population densities, in persons km⁻², as Remote (>0 to <1), Populated (1 to <10), Residential (10 to <100), Inhabited (>0 to <100), Villages and Mixed settlements (100 to <2,500), and Urban ( ≥2,500). Intensive anthromes are further stratified based on their dominant intensive land use area ≥20% in order of most intensive use (urban > rice > irrigated > cropped > pastured). Woodlands combine all forest and woodland biomes (73); drylands comprise the remaining biomes, from savanna to tundra, excluding permanent ice. Global uncertainties in SI Appendix, Fig. S1.

Fig. 2.

Regional changes in anthromes and populations 10,000 BCE to 2017 CE (regions indicated by lines in Fig. 1A ). Regional uncertainties in SI Appendix, Fig. S3.

Fig. 3.

Anthrome changes within biomes 10,000 BCE to 2017 CE. Biome uncertainties in SI Appendix, Fig. S4. Alternate biome systems are illustrated in SI Appendix, Fig. S5.

Fig. 4.

Anthrome histories related to present-day patterns of biodiversity and conservation. (A) Anthrome histories of KBAs (54), Protected Areas, Indigenous land areas (51), regions with Cultured anthromes and Wildlands in 2017, likely natural areas and potential natural areas [NMH (53)], and Shared Lands and Large Wild Areas of the Three Global Conditions [3GC (49)]. (B) Relative performance of past anthrome maps at predicting present-day patterns of biodiversity across all land globally and within the global subset of regional landscapes with >50% of their area covered by Indigenous land areas (51), NMH lands (53), and Protected Areas. Generalized linear models were fit to mean vertebrate species richness and threatened vertebrate species richness (55) per 100 km² and KBAs using each anthrome map, in turn, as a categorical predictor. The AIC indicates the relative association between anthrome maps at each time step and each contemporary pattern (AIC is only comparable for models fit to the same dataset, so rescaled values are shown here). Red dashed line marks transition from 1,000 y to 100 y time steps.