Tropical forests in the deep human past

Abstract

Since Darwin, studies of human evolution have tended to give primacy to open ‘savannah’ environments as the ecological cradle of our lineage, with dense tropical forests cast as hostile, unfavourable frontiers. These perceptions continue to shape both the geographical context of fieldwork as well as dominant narratives concerning hominin evolution. This paradigm persists despite new, ground-breaking research highlighting the role of tropical forests in the human story. For example, novel research in Africa's rainforests has uncovered archaeological sites dating back into the Pleistocene; genetic studies have revealed very deep human roots in Central and West Africa and in the tropics of Asia and the Pacific; an unprecedented number of coexistent hominin species have now been documented, including Homo erectus , the ‘Hobbit’ ( Homo floresiensis ), Homo luzonensis , Denisovans, and Homo sapiens . Some of the earliest members of our own species to reach South Asia, Southeast Asia, Oceania and the tropical Americas have shown an unexpected rapidity in their adaptation to even some of the more ‘extreme’ tropical settings. This includes the early human manipulation of species and even habitats. This volume builds on these currently disparate threads and, for the first time, draws together a group of interdisciplinary, agenda-setting papers that firmly places a broader spectrum of tropical environments at the heart of the deep human past. This article is part of the theme issue ‘Tropical forests in the deep human past’.

Global patterns and determinants of multiple facets of plant diversity

“…The output of our correlative models also suggests that the earlier onset of pastoralism might have influenced plant diversity globally, especially for FD and PD (see Figure 5), showing that botanical countries where pastoralism started earlier had lower diversity, and this pattern seems to be weakly linked to current human impacts (Figure S5). This is in agreement with recent findings highlighting that legacies of past anthropic disturbances might have strongly influenced current diversity patterns of both animals and plants (McMichael, 2021; McMichael et al., 2023; Polaina et al., 2019; Scerri et al., 2022). Recent mounting evidence has highlighted that extensive land use changes occurred much earlier in time than previously assessed (Mottl et al., 2021; Stephens et al., 2019), suggesting also that humans have been directly exploiting tropical forests since mid‐Holocene (ca.…”

“…Recent mounting evidence has highlighted that extensive land use changes occurred much earlier in time than previously assessed (Mottl et al., 2021; Stephens et al., 2019), suggesting also that humans have been directly exploiting tropical forests since mid‐Holocene (ca. 4 ka) (Scerri et al., 2022 and references therein). Specifically, the Neolithic revolution (i.e.…”

Consistent patterns of common species across tropical tree communities

“…We find common diversity patterns despite the very different histories of human occupancy in Amazonian, African and Southeast Asian tropical forests 40 . The relatively recent arrival of humans in Amazonia approximately 20,000 years ago has been linked to greater Pleistocene extinctions, in contrast to much longer human occupancy in the tropical forests of Africa and Southeast Asia 41 .…”

The human side of biodiversity: coevolution of the human niche, palaeo-synanthropy and ecosystem complexity in the deep human past

“…Recent research also indicates that the South American Amazon, a powerhouse of the planet's biodiversity, may be a large-scale human ecological legacy [32,[164][165][166], co-fabricated by past human societies over many millennia. The manipulation of tropical forest ecologies in Africa and Asia is now equally considered to have its roots in the Pleistocene [15,167,168]. Even before the Last Glacial Maximum (LGM), east-central European foragers of the Pavlovian (ca 31-27 kya) seem to have curated dead wood [169], which plays a key role in sustaining local biodiversity and provides crucial ecosystem services for other animals-especially birds, insects and amphibians-as well as understory vegetation and fungi [170].…”