Mauritius on fire: Tracking historical human impacts on biodiversity loss

Abstract

Fire was rare on Mauritius prior to human arrival (AD 1598); subsequently three phases of elevated fire activity occurred: ca 1630–1747, 1787–1833, and 1950–modern. Elevated fire frequency coincided with periods of high human impact evidenced from the historical record, and is linked to the extinction of island endemics.

A multimillennial climatic context for the megafaunal extinctions in Madagascar and Mascarene Islands

“…Plum and purple bars delineate the aragonite portions of stalagmites ABC-1 and AB2, respectively. Shaded bars on the top (with varying saturation intensity reflecting uncertainties) mark the timelines of permanent human settlements on Mauritius [red; ( 2 , 3 )], Rodrigues [blue; ( 5 )], and Madagascar [green; ( 16 , 18 )]. The vertical color bars with varying saturation intensity show correlative features in all δ 18 O time series.…”

“…S1) are recognized as biodiversity “hot spots”—highly threatened biogeographic regions with exceptional levels of endemic species ( 1 ). The large-scale biodiversity loss in Mascarenes, which were among the last places on Earth to be colonized by humans, occurred just within the past three or four centuries ( 2 – 4 ). Historical written accounts suggest that Mauritius lost most of its endemic species of terrestrial vertebrates within ~2 centuries of its initial colonization (c. 1638 CE), including the iconic species of the flightless bird Raphus cucullatus , popularly known as “Dodo” ( 4 ).…”

Human occupation and ecosystem change on Upolu (Samoa) during the Holocene

“…The close agreement between the macrocharcoal and the archaeological evidence suggests that humans were necessary to provide a source of ignition and/or sustain fire on Samoa, and mirrors similar patterns seen on Vanuatu, New Caledonia and Fiji (Hope, Stevenson, & Southern, ). The abundance of macrocharcoal found within the Upolu sediments is low (below 10 particles per cm 3 ) when compared with abundances found in sediments known to be associated with large‐scale landscape clearance (above > 200 particles per cm 3 ) on Mauritius (Gosling et al, ). The relatively low abundance of macrocharcoal on Upolu suggests that either fire activity within the lake catchment was very limited, or that larger scale fires elsewhere on the island contributed material via long‐distance transport.…”

“…Aside from the discovery of sites or artefacts representing a past material culture, one of the most effective direct measures for tracking past human activity has been found to be the presence, and abundance, of ancient (fossil) charcoal found in soils or sediments (following Whitlock & Larsen, ). The use of charcoal to track past human activity has been shown to be particularly effective in tropical settings where natural fire is limited due to either a lack of ignition source or flammability, that is, the appearance of fire is dependent on the arrival of humans (Argiriadis et al, ; Burney et al, ; Gosling et al, ; Huebert & Allen, ).…”

“…The use of charcoal to track past human activity has been shown to be particularly effective in tropical settings where natural fire is limited due to either a lack of ignition source or flammability, that is, the appearance of fire is dependent on the arrival of humans (Argiriadis et al, 2018;Burney et al, 2004;Gosling et al, 2017;Huebert & Allen, 2016).…”