TY  - JOUR
A1  - Garcin, Yannick
A1  - Deschamps, Pierre
A1  - Menot, Guillemette
A1  - de Saulieu, Geoffroy
A1  - Schefuss, Enno
A1  - Sebag, David
A1  - Dupont, Lydie M.
A1  - Oslisly, Richard
A1  - Brademann, Brian
A1  - Mbusnum, Kevin G.
A1  - Onana, Jean-Michel
A1  - Ako, Andrew A.
A1  - Epp, Laura Saskia
A1  - Tjallingii, Rik
A1  - Strecker, Manfred
A1  - Brauer, Achim
A1  - Sachse, Dirk
T1  - Early anthropogenic impact on Western Central African rainforests 2,600 y ago
JF  - Proceedings of the National Academy of Sciences of the United States of America
N2  - A potential human footprint on Western Central African rainforests before the Common Era has become the focus of an ongoing controversy. Between 3,000 y ago and 2,000 y ago, regional pollen sequences indicate a replacement of mature rainforests by a forest-savannah mosaic including pioneer trees. Although some studies suggested an anthropogenic influence on this forest fragmentation, current interpretations based on pollen data attribute the "rainforest crisis" to climate change toward a drier, more seasonal climate. A rigorous test of this hypothesis, however, requires climate proxies independent of vegetation changes. Here we resolve this controversy through a continuous 10,500-y record of both vegetation and hydrological changes from Lake Barombi in Southwest Cameroon based on changes in carbon and hydrogen isotope compositions of plant waxes. delta C-13-inferred vegetation changes confirm a prominent and abrupt appearance of C-4 plants in the Lake Barombi catchment, at 2,600 calendar years before AD 1950 (cal y BP), followed by an equally sudden return to rainforest vegetation at 2,020 cal y BP. delta D values from the same plant wax compounds, however, show no simultaneous hydrological change. Based on the combination of these data with a comprehensive regional archaeological database we provide evidence that humans triggered the rainforest fragmentation 2,600 y ago. Our findings suggest that technological developments, including agricultural practices and iron metallurgy, possibly related to the large-scale Bantu expansion, significantly impacted the ecosystems before the Common Era.
KW  - Western Central Africa
KW  - late Holocene
KW  - rainforest crisis
KW  - paleohydrology
KW  - human activity
Y1  - 2018
U6  - https://doi.org/10.1073/pnas.1715336115
SN  - 0027-8424
VL  - 115
IS  - 13
SP  - 3261
EP  - 3266
PB  - National Acad. of Sciences
CY  - Washington
ER  -