Ranking buffel: Comparative risk and mitigation costs of key environmental and socio-cultural threats in central Australia.

John L Read,Christine A Schlesinger,Jennifer Firn,Ellen Ryan-Colton,Rachel Murphy,Anthony C Grice

doi:10.1002/ece3.6724

Abstract

Changed fire regimes and the introduction of rabbits, cats, foxes, and large exotic herbivores have driven widespread ecological catastrophe in Australian arid and semi‐arid zones, which encompass over two‐thirds of the continent. These threats have caused the highest global mammal extinction rates in the last 200 years, as well as significantly undermining social, economic, and cultural practices of Aboriginal peoples of this region. However, a new and potentially more serious threat is emerging. Buffel grass (Cenchrus ciliaris L.) is a globally significant invader now widespread across central Australia, but the threat this ecological transformer species poses to biodiversity, ecosystem function, and culture has received relatively little attention. Our analyses suggest threats from buffel grass in arid and semi‐arid areas of Australia are at least equivalent in magnitude to those posed by invasive animals and possibly higher, because unlike these more recognized threats, buffel has yet to occupy its potential distribution. Buffel infestation also increases the intensity and frequency of wildfires that affect biodiversity, cultural pursuits, and productivity. We compare the logistical and financial challenges of creating and maintaining areas free of buffel for the protection of biodiversity and cultural values, with the creation and maintenance of refuges from introduced mammals or from large‐scale fire in natural habitats. The scale and expense of projected buffel management costs highlight the urgent policy, research, and financing initiatives essential to safeguard threatened species, ecosystems, and cultural values of Aboriginal people in central Australia.

Highlights

Four contemporary ecological disruptions are widely recognized as dramatically and irreversibly recasting the ecology of Australia's arid and semi-arid zones which cover over 70% of the continent, namely alteration of fire regimes as a consequence of displacement of Aboriginal peoples practicing traditional land management; overgrazing and soil compaction caused by the introduction of large exotic herbivores; predation of native wildlife by introduced red foxes (Vulpes vulpes) and domestic cats (Felis catus); and degradation of soils
They are responsible for broadscale losses in productivity and an erosion of traditional Aboriginal cultural values in central Australia (Woinarski, Burbidge, & Harrison, 2015)
A fifth major threat to Australian arid and semi-arid zone ecosystems has emerged and it is considered by many ecologists as “the single biggest invasive species threat to biodiversity across the entire Australian arid zone” (Biosecurity South Australia (SA), 2019)

Summary

Introduction

And often in concert, these four threatening processes have been largely responsible for the highest contemporary mammal extinction rates in the world and a bourgeoning inventory of threatened species (Kearney et al, 2018). They are responsible for broadscale losses in productivity and an erosion of traditional Aboriginal cultural values in central Australia (Woinarski, Burbidge, & Harrison, 2015). Plantings have occurred mostly since the late 1950s (Paull & Lee, 1978) and are continuing in some areas (Friedel, Puckey, O'Malley, Waycott, & Smyth, 2006), despite buffel being internationally recognized as causing broadscale and multilayered negative impacts on ecosystem processes, biodiversity, infrastructure, and human safety (e.g., Franklin & Molinafreaner, 2010; Godfree et al, 2017; McDonald & McPherson, 2013; Olsson, Betancourt, McClaran, & Marsh, 2012; Schlesinger, White, & Muldoon, 2013; Woinarski, 2004)

Methods

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Discussion

Conclusion