Fire mosaics and habitat choice in nomadic foragers
Rebecca Bliege Birda, Chloe McGuire, Douglas W. Bird, Michael H. Price, David Zeanah,
and Dale G. Nimmo
Proceedings of the National Academy of Sciences 2020
The abstract follows
"In the mid-1950s Western Desert of Australia, Aboriginal populations were in decline as families left for ration depots, cattle stations, and mission settlements. In the context of reduced population density, an ideal free-distribution model predicts landscape use should contract to the most productive habitats, and people should avoid areas that show more signs of extensive prior use. However, ecological or social facilitation due to Allee effects (positive density dependence) would predict that the intensity of past habitat use should correlate positively with habitat use. We analyzed fire footprints and fire mosaics from the accumulation of several years of landscape use visible on a 35,300-km2 mosaic of aerial photographs covering much of contemporary Indigenous Martu Native Title Lands imaged between May and August 1953. Structural equation modeling revealed that, consistent with an Allee ideal free distribution, there was a positive relationship between the extent of fire mosaics and the intensity of recent use, and this was consistent across habitats regardless of their quality. Fire mosaics build up in regions with low cost of access to water, high intrinsic food availability, and good access to trade opportunities; these mosaics (constrained by water access during the winter) then draw people back in subsequent years or seasons, largely independent of intrinsic habitat quality. Our results suggest that the positive feedback effects of landscape burning can substantially change the way people value landscapes, affecting mobility and settlement by increasing sedentism and local population density."
The article also contains the following lines
"During the 1950s, for example, two marauding brothers, Tirinji and Yawa, roamed the Great Sandy Desert on a violent rampage, murdering younger men and kidnapping women. Rumors of the brother’s serial killings circulated the surrounding settlements and the fear engendered by their violence lasted years; in 1964, when Western Australia Native Welfare officer Terry Long encountered a group of 20 Aboriginal women and children at the Percival Lakes, he reported that the women were “desperate to quit the area [. . .] they had no men for years and were frightened that if they did run into a group containing men that some of them would be killed, if they were considered unsuitable as wives.”
(References to this section
(a) N. J. Bent, P. Lowe, Eds., Two Sisters: Ngarta & Jukuna, (Fremantle Arts Centre Press, 2004).
(b) F. Skyring, “Ngurrara history report” [in the Federal Court of Australia, WA District Registry, Between Annette Kogolo, Butcher Wise, and Others, applicants, and the
State of Western Australia and Others, respondents—WAG6077 of 1998] (Broome, KLC, 1998).