Reply to Giresse et al.: No evidence for climate variability during the late Holocene rainforest crisis in Western Central Africa

Garcin, Yannick; Deschamps, Pierre; Ménot, Guillemette; Saulieu, Geoffroy de; Schefuß, Enno; Sebag, David; Dupont, Lydie M; Oslisly, Richard; Brademann, Brian; Mbusnum, Kevin G; Onana, Jean-Michel; Ako, Andrew Ako; Epp, Laura S.; Tjallingii, Rik; Strecker, Manfred R.; Brauer, Achim; Sachse, Dirk

doi:10.1073/pnas.1808481115

Cited by 3 publications

(2 citation statements)

References 8 publications

(10 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, the distinction between natural and human induced ecosystem shifts within these archives can be challenging. Human activities, such as deforestation or artificial fire, which lead to a loss of trees can easily be mixed up with natural effects like very dry climatic conditions (e.g., Clist et al, 2018;Garcin et al, 2018b;Maley et al, 2018;Bayon et al, 2019). Madagascar, characterized by one of the world's biologically richest ecosystems, does not deviate from this rule.…”

Section: Introductionmentioning

confidence: 99%

Rain Forest Fragmentation and Environmental Dynamics on Nosy Be Island (NW Madagascar) at 1300 cal BP Is Attributable to Intensified Human Impact

et al. 2022

View full text Add to dashboard Cite

Madagascar houses one of the Earth’s biologically richest, but also one of most endangered, terrestrial ecoregions. Although it is obvious that humans substantially altered the natural ecosystems during the past decades, the timing of arrival of early inhabitants on Madagascar as well as their environmental impact is still intensively debated. This research aims to study the beginning of early human impact on Malagasy natural ecosystems, specifically on Nosy Be island (NW Madagascar) by targeting the sedimentary archive of Lake Amparihibe, an ancient volcanic crater. Based on pollen, fungal spore, other non-pollen palynomorph, charcoal particle and diatom analyses combined with high-resolution sediment-physical and (in)organic geochemical data, paleoenvironmental dynamics during the past three millennia were reconstructed. Results indicate a major environmental change at ca. 1300 cal BP characterized by an abrupt development of grass (C4) dominated and fire disturbed landscape showing the alteration of natural rain forest. Further, increased soil erodibility is suggested by distinct increase in sediment accumulation rates, a strong pulse of nutrient input, higher water turbidity and contemporaneous increase in spores of mycorrhizal fungi. These parameters are interpreted to show a strong early anthropogenic transformation of the landscape from rain forest to open grassland. After ca. 1000 cal BP, fires remain frequent and vegetation is dominated by forest/grassland mosaic. While natural vegetation should be dominated by rain forest on Nosy Be, these last results indicate that human continuously impacted the landscapes surrounding the lake. At a local scale, our data support the “subsistence shift hypothesis” which proposed that population expansion with development of herding/farming altered the natural ecosystems. However, a precise regional synthesis is challenging, since high-resolution multi-proxy records from continuous sedimentary archives as well as records located further north and in the hinterland are still scarce in Madagascar. The lack of such regional synthesis also prevents precise comparison between different regions in Madagascar to detect potential (dis)similarities in climate dynamics, ecosystem responses and anthropogenic influences at the island’s scale during the (late) Holocene.

show abstract

Section: Introductionmentioning

confidence: 99%

Rain Forest Fragmentation and Environmental Dynamics on Nosy Be Island (NW Madagascar) at 1300 cal BP Is Attributable to Intensified Human Impact

et al. 2022

View full text Add to dashboard Cite

show abstract

“…In the mid -1st century BCE, most of the smelting sites on Elba Island were abandoned [28,33,38,42]. It is widely supposed that a lack of fuel caused the abandonment of smelting on the island [21,23,34,35,[43][44][45][46][47][48][49][50][51][52][53]. Other authors mention the role of deforestation and the scarcity of resources as leading to the decline of metallurgy on Elba Island as well as in Populonia [54,55].…”

Section: Introductionmentioning

confidence: 99%

The furnace and the goat—A spatio-temporal model of the fuelwood requirement for iron metallurgy on Elba Island, 4th century BCE to 2nd century ce

et al. 2020

View full text Add to dashboard Cite

Scholars frequently cite fuel scarcity after deforestation as a reason for the abandonment of most of the Roman iron smelting sites on Elba Island (Tuscan Archipelago, Italy) in the 1st century bce. Whereas the archaeological record clearly indicates the decrease in smelting activities, evidence confirming the ‘deforestation narrative’ is ambiguous. Therefore, we employed a stochastic, spatio-temporal model of the wood required and consumed for iron smelting on Elba Island in order to assess the availability of fuelwood on the island. We used Monte Carlo simulations to cope with the limited knowledge available on the past conditions on Elba Island and the related uncertainties in the input parameters. The model includes both, wood required for the furnaces and to supply the workforce employed in smelting. Although subject to high uncertainties, the outcomes of our model clearly indicate that it is unlikely that all woodlands on the island were cleared in the 1st century bce. A lack of fuel seems only likely if a relatively ineffective production process is assumed. Therefore, we propose taking a closer look at other reasons for the abandonment of smelting sites, e.g. the occupation of new Roman provinces with important iron ore deposits; or a resource-saving strategy in Italia. Additionally, we propose to read the development of the ‘deforestation narrative’ originating from the 18th/19th century in its historical context.

show abstract

Diversification, Intensification and Specialization: Changing Land Use in Western Africa from 1800 BC to AD 1500

et al. 2019

View full text Add to dashboard Cite

Many societal and environmental changes occurred between the 2nd millennium BC and the middle of the 2nd millennium AD in western Africa. Key amongst these were changes in land use due to the spread and development of agricultural strategies, which may have had widespread consequences for the climate, hydrology, biodiversity, and ecosystem services of the region. Quantification of these land-use influences and potential feedbacks between human and natural systems is controversial, however, in part because the archaeological and historical record is highly fragmented in time and space. To improve our understanding of how humans contributed to the development of African landscapes, we developed an atlas of landuse practices in western Africa for nine time-windows over the period 1800 BC-AD 1500. The maps are based on a broad synthesis of archaeological, archaeobotanical, archaeozoological, historical, linguistic, genetic, and ethnographic data, and present land use in 12 basic categories. The main differences between categories is the relative reliance on, and variety of, domesticated plant and animal species utilized, and the energy invested in cultivating or keeping them. The maps highlight the irregular and frequently non-linear trajectory of land-use change in the prehistory of western Africa. Representing an original attempt to produce rigorous spatial synthesis from diverse sources, the atlas will be useful for a range of studies of human-environment interactions in the past, and highlight major spatial and temporal gaps in data that may guide future field studies.

show abstract

Reply to Giresse et al.: No evidence for climate variability during the late Holocene rainforest crisis in Western Central Africa

Cited by 3 publications

References 8 publications

Rain Forest Fragmentation and Environmental Dynamics on Nosy Be Island (NW Madagascar) at 1300 cal BP Is Attributable to Intensified Human Impact

Rain Forest Fragmentation and Environmental Dynamics on Nosy Be Island (NW Madagascar) at 1300 cal BP Is Attributable to Intensified Human Impact

The furnace and the goat—A spatio-temporal model of the fuelwood requirement for iron metallurgy on Elba Island, 4th century BCE to 2nd century ce

Diversification, Intensification and Specialization: Changing Land Use in Western Africa from 1800 BC to AD 1500

Contact Info

Product

Resources

About