Gran Sabana fires (SE Venezuela): a paleoecological perspective

Abstract

Fires are among the most important risks for tropical ecosystems in a future climatic change scenario. Recently, paleoecological research has been addressed to discern the role played by fire in neotropical landscapes. However, given the magnitude of the Neotropics, many studies are relegated to infer just local trends. Here we present the compilation of the paleo-fire records developed until now in the southern Gran Sabana (SE Venezuela) with the aim to describe the fire history as well as to infer the possible forcing factors implied. In this sense, southern Gran Sabana has been under fire perturbation since the Lateglacial, with the concomitant effects upon vegetation, and persisted during the Holocene. Around 2000 cal yr BP onwards, the fire activity highly increased promoting the expansion of pre-existing savannas, the decrease of forests and the appearance and establishment of Mauritia palm swamps. The continuous fire incidence registered for several thousands of years has likely promoted the supremacy of treeless savannas upon other vegetation types and the degradation to secondary landscapes. Based on the available evidence, the anthropogenic nature of this high fire activity has been postulated. If so, it could be hypothesized that the timing arrival of Pemón, the present-day indigenous culture in the Gran Sabana, would be ca 2000 cal yr BP onwards, rather than the last centuries, as it has been formerly assumed. The implications of these ancient practices in the area are also discussed for present Gran Sabana landscapes sustainability and future conservation strategies.

New Insights From Pre-Columbian Land Use and Fire Management in Amazonian Dark Earth Forests

“…The increase in Mauritia/Mauritiella follows a similar pattern to sites across seasonally flooded savannas in lowland South America during this period (Kahn and de Granville, 1992;Behling and Hooghiemstra, 1998Burbridge et al, 2004;Montoya and Rull, 2011;Montoya et al, 2011b;Balee, 2013;Rull et al, 2013;Rull and Montoya, 2014;Maezumi et al, 2015;Junqueira et al, 2017). This regional phenomenon has been attributed to both natural and anthropogenic drivers (Montoya and Rull, 2011;Montoya et al, 2011a,c;Rull and Montoya, 2014;Maezumi et al, 2015). Disentangling climate and pre-Columbian drivers of the late Holocene expansion of Mauritia/Mauritiella and other useful plants is complicated by the synchroneity of changes in regional climate (Baker et al, 2001b;Cruz et al, 2009;Novello et al, 2012;Wang et al, 2017) and the apex of pre-Columbian activity in lowland Amazon during this time (Roosevelt, 1999;Schaan, 2010Schaan, , 2012Gomes, 2011;Schaan et al, 2012;Stenborg et al, 2012).…”

“…the increase in edible plants at LC is driven primarily by Mauritia/Mauritiella, along with Agavaceae, Caryocar, Byrsonima, Lecythidaceae, and Theobroma among others (Figure 6). The increase in Mauritia/Mauritiella follows a similar pattern to sites across seasonally flooded savannas in lowland South America during this period (Kahn and de Granville, 1992;Behling and Hooghiemstra, 1998Burbridge et al, 2004;Montoya and Rull, 2011;Montoya et al, 2011b;Balee, 2013;Rull et al, 2013;Rull and Montoya, 2014;Maezumi et al, 2015;Junqueira et al, 2017). This regional phenomenon has been attributed to both natural and anthropogenic drivers (Montoya and Rull, 2011;Montoya et al, 2011a,c;Rull and Montoya, 2014;Maezumi et al, 2015).…”

Effects of past climate variability on fire and vegetation in the cerrãdo savanna of the Huanchaca Mesetta, NE Bolivia

“…The long-term role of humans on vegetation and fire regimes of the cerrãdo remains unclear. There is increasing evidence for a late Holocene (3000 cal yr BP) increase in Mauritia flexuosa (M. flexuosa) and fire activity in Bolivia, Colombia, Venezuela, and Brazil, which has been attributed to both natural and anthropogenic drivers (Behling and Hooghiemstra, 1999;Berrio et al, 2002a;DaSilva Meneses et al, 2013;Kahn and de Castro, 1985;Kahn, 1987Kahn, , 1988Montoya and Rull, 2011;Rull, 2009).…”

Paleoecology as a guide to landscape conservation and restoration in the neotropical Gran Sabana

“…7 to 5 cal ka BP), likely due to a general increase in the available moisture (Montoya et al 2011b;Rull et al 2016). Mauritia flexuosa arrived to the Gran sabana by 2 cal ka BP, coinciding with a significant exacerbation of fire, considered to be the onset of the present-like indigenous fire management practices, and the establishment of modern Gran sabana landscapes (Montoya and Rull 2011;Montoya et al 2011c; Fig. 2).…”