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Mammals on the Brink

short-eared rock wallabies

Perhaps because of their rocky, inaccessible habitat, short-eared rock wallabies are one of a few species whose populations remain healthy in much of the Northern Territory. Credit: Ian Morris

By Mark Ziembicki

Traditional ecological knowledge and western science have combined to address one of Australia’s most pressing biodiversity conservation issues – the decline of its native mammal species.

Pulling into Mapuru, a remote outstation on the edge of the Arnhem Land plateau, our car is held hostage by a large pack of barking camp dogs. Unwilling to brave an exit, we remain trapped until some local kids chase the canines away and we cautiously step out of the vehicle to be welcomed by our hosts, the traditional land owners of the area. As the dogs hover at a distance I wonder whether they somehow sense what is in the back of our ute.

The outstation is another stop on an extended field trip across Arnhem Land that aims to document Aboriginal people’s knowledge of some of our most threatened wildlife. In the back of the Toyota is a prized collection of stuffed museum mammal specimens – a travelling puppet show of sorts – carefully prepared in life-like poses to help with our interviews.

As the billy tea boils nearby, several elders and a few younger people gather on a canvas tarp laid out under the shade of a large Darwin Woollybutt. From the back of the Toyota I bring out the collection of animals I’ve brought from Darwin.

We are up to the tree rats. As the children giggle and point at the models, the elders reminisce about hunting these large arboreal rats and how they used to cook them. I pick up kordberr, the local name for the golden-backed tree rat. One of the younger women who had remained silent until now suddenly speaks up. “I seen that one – last year… down the road, near the creek crossing,” she says. Somewhat taken aback and mildly sceptical I ask: “Are you sure it was this one, and not one of these?” pointing to other similar, more common tree rat species. “No,” she responds emphatically. “It was like that one. It had a long, white tail and that colour on its back.” As she continues describing it and the habitat in which she saw it I grow increasingly excited and convinced we are talking about the same species – one that scientists have not recorded in the Northern Territory since the late 1960s.

Observations such as these are priceless for scientists like me. Since European arrival Australia has suffered a catastrophic loss of native mammals, with 22 species becoming extinct and a further eight persisting only as residual populations on offshore islands. Most of these extinctions occurred in inland and southern Australia by around the turn of the last century, and for a long time our northern landscapes were regarded as a refuge for mammals.

Recent evidence from localised surveys and comparisons with historical records suggest there have been major declines of several mammal species in parts of monsoonal northern Australia. However, this information comes from a limited number of sources and there are examples of inconsistency, such as the high rainfall zones of the Kimberley where the mammal fauna remains stable.

Our limited knowledge of the mammals of the north is a major impediment to developing adequate responses to such potential problems. Australia’s native mammals are inherently difficult to study. They are mostly small and nocturnal, and because much of the country is so sparsely populated and the distances so vast we have limited understanding of where and when these declines have been happening. This makes it difficult to assess the conservation status of species and to pinpoint potential population declines and the reasons behind them.

To help address these gaps in our knowledge, a collaborative research project between the Australian National University, the Northern Territory government, The Wilderness Society and Aboriginal communities across the Top End has been launched. Its aim is to bring together traditional ecological knowledge and scientific knowledge to chart the status and distribution of mammal species across the monsoonal region of the Northern Territory. When combined with data from other sources, the information will help chart patterns of distribution that can be related to environmental factors, such as land use, topography and fire regimes, to help identify the reasons for the declines and the success of management actions (such as protected areas) in conserving species.

Over the course of the project we visited more than 30 communities and travelled more than 35,000 km by light plane, car, boat and on foot. Thanks to indigenous knowledge we greatly increased the number of records for many species. We learnt, for example, that the brush-tailed phascogale was more widespread in the past than scientists knew, although its numbers are declining. Of the 17 species that were considered in detail (because there were adequate records to allow meaningful comparisons), most declined over the period of the memory of indigenous participants. These changes were reported across the whole study area and were greater for the ‘‘critical weight range’’ species – medium-sized mammals such as quolls, bandicoots, possums, large rats and small wallabies. Few species increased. The most pronounced increase was for the agile wallaby but such increases were relatively limited.

Overall the study revealed a pattern of widespread decline in the mammal fauna of the monsoonal tropics of northern Australia, which is consistent with recent local wildlife monitoring studies. It also demonstrated the value and capability of traditional ecological knowledge to complement and extend our scientific knowledge. The use of traditional ecological knowledge is increasingly recognised for its value to contemporary natural resource management and biodiversity conservation. As this study showed, it may be particularly helpful because it may be best retained in remote areas where scientific information is lacking and because, unlike most short-term scientific studies, it is based on continual observations and on information accumulated over many generations. Use and respect for traditional ecological knowledge may also directly aid in conservation and management actions among indigenous landholders, especially where management actions imposed via scientific approaches are regarded as foreign or difficult to understand, and are therefore not easily supported.

Unfortunately there has been a significant decrease in traditional Aboriginal practices and an associated loss of traditional ecological knowledge and Aboriginal languages. These days Aboriginal people have largely western diets and no longer hunt animals that were once staple foods. Paradoxically, the end of hunting may have contributed to the decline of some mammal species because with its cessation people no longer practice traditional land management techniques that benefited the animals, such as fire-stick farming.

This suggests a close relationship between the decline of indigenous knowledge and the decline of biodiversity. As knowledge is not being passed onto the next generation, traditional practices are in danger of being lost, and with that, thousands of years of experience in managing Australia’s environment.

In this study we were fortunate to work with members of the older generation who were most responsible for and most experienced in traditional management, with sometimes encyclopaedic knowledge of the nature of their country. This is an opportunity lost for many regions in Australia.

However, in this region it is an opportunity that has been capitalised on with cultural revival and the establishment of indigenous ranger groups (AS, March 2013, pp.34–36) that seek to re-establish traditional management practices over large areas in order to maintain or restore ecological function. Part of this cultural regeneration has included closer collaborative ties between Aboriginal landowners and scientists through, for example, joint management of national parks, the reintroduction of traditional fire regimes, and collaborative species management, research and conservation initiatives.

In this region the fate of the native mammal fauna, and biodiversity more generally, may hinge on the retention, valuation and broader application of traditional knowledge.

Mark Ziembicki is a Senior Research Fellow in James Cook University’s Centre for Tropical Environmental and Sustainability Science and School of Marine & Tropical Biology. The research reported here was published in Biological Conservation 157, 78–92.