Christopher H. Parker

The “fire stick farming” hypothesis: Australian Aboriginal foraging strategies, biodiversity, and anthropogenic fire mosaics

Aboriginal burning in Australia has long been assumed to be a “resource management” strategy, but no quantitative tests of this hypothesis have ever been conducted. We combine ethnographic observations of contemporary Aboriginal hunting and burning with satellite image analysis of anthropogenic and natural landscape structure to demonstrate the processes through which Aboriginal burning shapes arid-zone vegetational diversity. Anthropogenic landscapes contain a greater diversity of successional stages than landscapes under a lightning fire regime, and differences are of scale, not of kind. Landscape scale is directly linked to foraging for small, burrowed prey (monitor lizards), which is a specialty of Aboriginal women. The maintenance of small-scale habitat mosaics increases small-animal hunting productivity. These results have implications for understanding the unique biodiversity of the Australian continent, through time and space. In particular, anthropogenic influences on the habitat structure of paleolandscapes are likely to be spatially localized and linked to less mobile, “broad-spectrum” foraging economies.

The pyrophilic primate hypothesis

Members of genus Homo are the only animals known to create and control fire. The adaptive significance of this unique behavior is broadly recognized, but the steps by which our ancestors evolved pyrotechnic abilities remain unknown. Many hypotheses attempting to answer this question attribute hominin fire to serendipitous, even accidental, discovery. Using recent paleoenvironmental reconstructions, we present an alternative scenario in which, 2 to 3 million years ago in tropical Africa, human fire dependence was the result of adapting to progressively fire‐prone environments. The extreme and rapid fluctuations between closed canopy forests, woodland, and grasslands that occurred in tropical Africa during that time, in conjunction with reductions in atmospheric carbon dioxide levels, changed the fire regime of the region, increasing the occurrence of natural fires. We use models from optimal foraging theory to hypothesize benefits that this fire‐altered landscape provided to ancestral hominins and link these benefits to steps that transformed our ancestors into a genus of active pyrophiles whose dependence on fire for survival contributed to its rapid expansion out of Africa.

What's burning got to do with it? Primate foraging opportunities in fire-modified landscapes

OBJECTIVES Anecdotal and formal evidence indicate that primates take advantage of burned landscapes. However, little work has been done to quantify the costs and benefits of this behavior. Using systematic behavioral observations from a population of South African vervet monkeys (Chlorocebus aethiops pygerythrus), we evaluate differences in food availability and energetics before and after controlled burns altered vegetation near their home range. We aim to determine whether burned habitats offer improved foraging opportunities. METHODS We collected feeding data from foraging individuals and analyzed common plant foods for their energetic content. We then used the feeding and energetic data to calculate postencounter profitabilities and encounter rates for food types. Using negative binomial and mixed linear regression models we compared data from burned and unburned habitats. RESULTS Our results show significantly improved encounter rates in burned landscapes for two prey items, invertebrates and grasses. However, postencounter profitabilities in burned areas were not significantly different than those achieved in unburned areas. CONCLUSIONS Results suggest that improved encounters alone can motivate changes in foraging behavior. These foraging benefits enable the exploitation of burned savanna habitats, likely driving postburn range expansions observed among populations of vervet monkeys. Thus quantified, these results may serve as a foundation for hypotheses regarding the evolution of fire-use in our own lineage.

Burning and Hunting in Australia’s Western Desert

Even though the central role of fire in the terrestrial biodiversity of Australia is widely acknowledged, we have a limited understanding of the factors that determine the decisions that Aborigines make in maintaining landscape burning regimes (see review in Bowman 1998, pp. 389-390). Discussions of Aboriginal firing practices have generally focused on three interrelated aspects: (1) possible changes in burning regimes indicated by paleoecological records coincident with the arrival of humans in Australia, and subsequent changes in vegetation demography and distribution; (2) the relationship between firing, the primary extinction of Pleistocene mega fauna, and historic declines and extinctions of small-medium-sized marsupials; and (3) the role of Aboriginal burning as a general land management strategy for increasing food supplies and maintaining wildlife habitats. Our aim is to address the fire management issue with data on the immediate and long-term benefits accruing to Martu Aborigines in the Western Desert of Australia.