Cultural legacies, fire ecology, and environmental change in the Stone Country of Arnhem Land and Kakadu National Park, Australia

Abstract

We use the fire ecology and biogeographical patterns of Callitris intratropica, a fire-sensitive conifer, and the Asian water buffalo (Bubalus bubalis), an introduced mega-herbivore, to examine the hypothesis that the continuation of Aboriginal burning and cultural integration of buffalo contribute to greater savanna heterogeneity and diversity in central Arnhem Land (CAL) than Kakadu National Park (KNP). The ‘Stone Country’ of the Arnhem Plateau, extending from KNP to CAL, is a globally renowned social–ecological system, managed for millennia by Bininj-Kunwok Aboriginal clans. Regional species declines have been attributed to the cessation of patchy burning by Aborigines. Whereas the KNP Stone Country is a modern wilderness, managed through prescribed burning and buffalo eradication, CAL remains a stronghold for Aboriginal management where buffalo have been culturally integrated. We surveyed the plant community and the presence of buffalo tracks among intact and fire-damaged C. intratropica groves and the savanna matrix in KNP and CAL. Aerial surveys of C. intratropica grove condition were used to examine the composition of savanna vegetation across the Stone Country. The plant community in intact C. intratropica groves had higher stem counts of shrubs and small trees and higher proportions of fire-sensitive plant species than degraded groves and the savanna matrix. A higher proportion of intact C. intratropica groves in CAL therefore indicated greater gamma diversity and habitat heterogeneity than the KNP Stone Country. Interactions among buffalo, fire, and C. intratropica suggested that buffalo also contributed to these patterns. Our results suggest linkages between ecological and cultural integrity at broad spatial scales across a complex landscape. Buffalo may provide a tool for mitigating destructive fires; however, their interactions require further study. Sustainability in the Stone Country depends upon adaptive management that rehabilitates the coupling of indigenous culture, disturbance, and natural resources.

Small islands, valuable insights: systems of customary resource use and resilience to climate change in the Pacific

“…For example, in shifting agriculture systems, the process of succession is manipulated as ecological communities and landscapes are managed through temporary small-scale clearings and, in many cases, controlled fires. There is growing evidence that some customary resource management systems in the Pacific can play a key role in maintaining ecological integrity in the context of disturbance (Ticktin et al 2006, Bird et al 2012, Trauernicht et al 2013. Customary resource management systems have also been recognized as key to building adaptive capacity in small Pacific Islands (Campbell 2006, Barnett and Campbell 2010, Vaughan and Vitousek 2013, but they continue to be modified under rapidly changing social, economic, and ecological contexts (Cinner and Aswani 2007, Brewer et al 2012, Lauer et al 2012).…”

Clarifying the confusion: old-growth savannahs and tropical ecosystem degradation

“…Although in pre-human history, savannah fires were ignited by lightning strikes, in most of the world's savannahs, humans are now the primary sources of ignitions [2,51,52]. Similarly, most savannahs support populations of native and/or domestic herbivores, often under human management [11,53]. When fires are excluded (often because they are viewed as unnatural or destructive) and/or herbivores are improperly managed, woody plants may rapidly increase in abundance.…”

“…In recent literature, this confusion is attributed to several interrelated causes, including misperceptions of savannahs as successional vegetation [1], the outdated, but still influential, idea of potential vegetation [2], use of physiognomic rather than functional or floristic definitions of savannah and forest [3], failure to distinguish natural savannahs of native species from grasslands resulting from deforestation [4] and undervaluation of savannah biodiversity and ecosystem services [5]. This confusion hinders savannah conservation efforts [1], obscures biodiversity losses due to agricultural conversion, afforestation and forest expansion [6,7], impedes scientific advances [8,9], and threatens people who depend upon savannahs for their livelihoods [10,11].…”

Fauna and vegetation responses to fire and invasion by toxic cane toads (Rhinella marina) in an obligate seeder-dominated tropical savanna in the Kimberley, northern Australia

“…In contrast to resprouter-dominated savannas, more fireresponsive elements within savanna vegetation, including obligate seeders, have more pronounced responses. Callitris intratropica is often cited as a species declining within the savanna matrix because of its inability to resprout after canopy scorch with high-intensity fire (Bowman et al 2001;Trauernicht et al 2013). Obligate-seeder heath species on the Arnhem Land Plateau are also considered under threat from high frequency fire regimes where maturation periods exceed interfire intervals (Russell- Smith et al 2003).…”

“…Fisher 1995a, 1995b). Aside from a small number of one-off descriptive studies of floral and faunal communities associated with these savanna subelements Fisher 1995a, 1995b;Trauernicht et al 2013;Radford et al 2013), little is known of the dynamics of fire responses among most of these vegetation types and their associated biota (Russell-Smith et al 2010).…”