In Langscape Magazine Articles

Culturally-Mediated Disturbance: Building a Bridge Between Knowledge Systems to Conserve Biocultural Diversity in New Guinea

August 04, 2015

by William H. Thomas

biocultural diversity

With no roads and few services, Hewa traditions remain vibrant. Photo: William H. Thomas, 2007

Buried deep within the Western psyche rests a romantic myth that neither evidence nor exposure has been able to extinguish—the Noble Savage. Although it no longer has scientific currency, the idea that traditional societies uncorrupted by civilization are able to live in balance with their surroundings continues to subtly permeate the discourse on the place of these societies in the modern world. While there is no question that traditional societies have done a better job as stewards of their lands, some of the more romantic elements of this myth are just not true and are threatening to destroy the emerging partnership between traditional people and conservationists.

When I began studying anthropology in the 1980s, evidence of humanity’s role in shaping landscapes was hitting the scientific literature. Suddenly, humanity’s fingerprints were everywhere. When even the Amazon showed signs of management, wilderness advocates were forced to consider the possibility that humans had played a role in shaping every landmass outside of Antarctica. Although disappointing for purists, this sounded like good news for some conservationists who now saw an opportunity to enlist Indigenous Peoples in the conservation of their traditional lands. After all, the last great tracts of forest, desert, and plains were their homelands. With their encyclopedic knowledge of their surroundings, it seemed reasonable to conservationists that traditional societies had solved the riddle of living in a biologically diverse world. If the Western world could just learn their secrets, they reasoned, we could partner with them to save the earth’s remaining wild lands.

biocultural diversity

The Hewa territory encompasses 200,000 hectares of sub-montane forest in the Laigaip River catchment in the center of the island of New Guinea. Photo: William H. Thomas, 2011

Things didn’t quite go as the conservationists had expected. Wildlife within the new reserves began to disappear. Landowners began clearing gardens within the newly designated parks. Overall biodiversity dropped and the phenomenon of “paper parks”—parks that existed on paper but not in reality—emerged. What went wrong? The short answer is that we were naïve about the relationship of Indigenous Peoples to biodiversity. The landscapes that we sought to conserve had been shaped by Indigenous Peoples, but not by the light touch of the Noble Savage, nor by the comprehensive knowledge of Indigenous ecosystem managers, as they began to be described in the literature of the 1980s. Rather, biodiversity was the unintended by-product of small Indigenous populations moving across the land, self-sufficient and without the pressures of the market system. In the course of their traditional lives, Indigenous Peoples promoted biodiversity by creating a series of small-scale disturbances as they used their land and then moved on when fertility or production fell. This cycle increased two measures of biodiversity by creating ecological diversity—cleared/grazed land and forest/grassland succession—and thereby introducing new organisms not found in climax ecosystems. However, while people used the resulting biodiversity, that biodiversity was a by-product of disturbance, not the aim of traditional life.

In essence, we were working with the wrong model. Throughout our history, modern Western societies have treated the earth like a machine to be managed for the good of their citizens. To keep the machine in good running order, you first need to know all the parts and how they are connected. The ongoing effort by science to catalogue the natural world is a product of this worldview. Once understood, managers could fine-tune nature’s machinery to keep the system running smoothly. Soil depleted? Just add fertilizer. Are bugs eating your crops? We will find a poison or a predator; inject it into the equation and presto—no more problems! This idea of managing nature through a straight-line relationship between inputs and outcomes is known as “linear” thinking.

In the course of their traditional lives, Indigenous Peoples promoted biodiversity by creating a series of small-scale disturbances as they used their land and then moved on when fertility or production fell.

Nature, however, is not a linear system. One of the greatest discoveries in my lifetime has been that nature is so intricately connected that we may never be able to parse the web of connectivity. With each breakthrough in microscopy, we discover new interconnected worlds. In these worlds, every organism is connected and the actions of each affect the others. Known as the “butterfly effect,” this connectivity is the reason that our hopes of managing nature’s machinery remain a fantasy. If no one can possibly list all of the organisms and connections that comprise an ecosystem, how can anyone manage an ecosystem?

Indigenous landowners, able to thrive in landscapes so biologically diverse that they merited protection, seemed like ecosystem managers and ideal partners in conservation. However, by restricting access to the parks and providing services like healthcare to undeveloped regions, conservation changed the system that promoted biodiversity. Development became a magnet, attracting more people to remote areas. In their desire to live close to services, formerly semi-nomadic people became sedentary. With few jobs, fewer relocation options and equipped with traditions that evolved in sparsely populated areas, the growing populations of humans outside of the parks soon outstripped the available resources and were forced to use the parks’ resources for their survival. Once these modern-day traditional societies were confronted with the new circumstances that accompanied conservation, they were overwhelmed and unable to conserve the biological mosaic that had attracted conservationists in the first place.

In 1988, I was living with the Hewa people of Papua New Guinea. Their lands are in the center of the island of New Guinea, in the mountains surrounding the headwaters of the Strickland River. The Hewa live in the least explored region of this island, with no roads connecting them to the nearby highlands. As with the Amazon, we now know that these forests are biocultural phenomena—environments shaped by humans. I was here to learn the role the Hewa played in shaping these forests and test Darrell Posey’s hypothesis that tradition can provide a template for conservation.

The Hewa never spoke of their desire to balance their lives with those of the creatures in the forests. There were fewer than 2,000 people scattered over 120,000 hectares with no need for taboos to promote conservation. They cut trees, made gardens, and shot anything that moved, yet seemingly had no effect on their forest. What was their secret? Ultimately, the Hewa understanding of birds and their role in forest regeneration provided a clue. Birds are an internationally recognized indicator of biological diversity and the most important agents of seed dispersal and forest regeneration in New Guinea. By sharing with me their traditional knowledge of birds and the impact of human activity on them, the Hewa have exposed the link between disturbance and biodiversity. This link enabled me to bridge the gap between their knowledge system and conservationists.

biocultural diversity

The Hewa live in scattered households throughout their forest. From ground level, their homesteading can seem insignificant. Photo: William H. Thomas, 2010

The Hewa describe their lives and gardening as a major source of disturbance in the forest. Much like the earthquakes and landslides that shape their land, they are a creative force, shaping their land by clearing trees for gardens. Low soil fertility forces them to continually move across the landscape cutting small gardens, harvesting their produce, and moving on. As they go about their lives, they forge a patchwork of forest, garden, and forest succession that gives rise to diversity by creating different habitats. This human-generated patchwork supports 184 species of birds and contains more habitats and more organisms than would be found in an unaltered landscape. Again, the Hewa do not describe traditional life as living in “balance” with nature. Instead, they recognize that they both create and destroy habitats with their gardening, designating the forest succession of 20 years as “old garden,” Agwe Teli; that of 25–50 years as “old garden true,” Agwe Teli Popi; and primary forest as Nomakale “place of the big trees.”

biocultural diversityThrough disturbance, the Hewa are inextricably linked to the biological diversity found in their homeland. They generate biodiversity by creating new habitats and introducing new species into a region that is otherwise dominated by one habitat—primary forest. There is a catch, however: the diversity-generating power of disturbance is scale-dependent. Although small-scale disturbances can enhance the diversity of a landscape, large-scale disturbance will simplify it—and too many small-scale disturbances can combine to have the same simplifying effect as a large disturbance. Using birds as a proxy, you can glimpse both the diversity-enhancing and the destructive power of gardening. If you compare the diversity of birds found within each of the habitats created by gardening with the old-growth forest, you will find that each stage of forest regeneration is host to different but fewer species of birds (i.e., it is less diverse than the primary forest). Gardening creates an environment that is not used by most of the fruit- and nectar-eating birds this forest depends on for regeneration. According to the Hewa, removal of the primary forest from a garden site will eliminate thirty-three percent of the birds and nearly all of the frugivores now found there. They also know that shortening the fallow period for gardens to less than twenty years will remove another forty-two species, eliminating iconic species like the cassowary. In other words, traditional gardening techniques that now help to promote diversity by creating new environments with species not present in the primary forest can quickly degrade the environment if the gardeners’ movements are limited or their numbers increase. Should a patchwork of small disturbances come to dominate the landscape, the land will become less diverse, losing the creatures that can only survive in the primary forest and eventually become unworthy of conservation. In New Guinea, this means that landscape will lose the fantastic Birds of Paradise that originally spurred interest in conserving the Hewa lands.

biocultural diversity

When seen from overhead, the amount of disturbance and the associated stages of forest regeneration associated with a Hewa family compound become apparent. Photo: William H. Thomas, 2012

biocultural diversity

As the Hewa shift to more fertile soils, they leave behind a mosaic of biomes as the forest regenerates. Photo: William H. Thomas, 2010

The role of disturbance in creating biodiversity and the comparatively lower diversity within the newly created habitats are the keys to understanding the ability of traditional societies to coexist with biodiversity. Small traditional societies did not have to do anything more than pursue their interests in raising food to become a positive force for biodiversity. I believe that Westerners were culturally predisposed to misinterpret the relationship between tradition and biodiversity as a balancing act, mistaking their informants’ metaphors for a conservation blueprint. In reality, traditional landowners are a force in nature. They can create new environments and enhance biodiversity if they move across the landscape and allow the forest to regenerate. The challenge for all parties lies in harnessing this creative force for conservation-based development, wherein culture is considered the key, not the barrier to self-guided development.

Small traditional societies did not have to do anything more than pursue their interests in raising food to become a positive force for biodiversity.

biocultural diversity

The Hewa are enthusiastic hunters and willingly share their knowledge with those who can keep up with them. Photo: William H. Thomas, 2007

I believe that recognition of the connection between disturbance and biodiversity will be crucial to the conservation of tropical forests. We now realize that disturbance generates biodiversity—something the Hewa already knew. Traditional activities are then best described as another source of disturbance, a vital component of biologically diverse landscapes. Since the government of Papua New Guinea insists that the landowners generate any conservation proposals, the Hewa have not only the knowledge, but also the ability to control their future. A vibrant traditional knowledge base may actually give the Hewa greater control over their future by allowing them to more fully participate in the conservation process. If we can work with them during the conservation process, we can build upon the connection between tradition and biodiversity to create a culture-friendly template for the conservation of New Guinea’s forests.


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William H. Thomas is Director of the New Jersey School of Conservation at Montclair State University in New Jersey, USA. He has conducted research in Papua New Guinea since 1988. He has developed a “Forest Stewards” program to conserve New Guinea’s wild lands. UNESCO has recognized his work as a “Best Practice.” Read more from William H. Thomas.

Further Reading

Swartzendruber, J. F. (1993). Conservation Needs Assessment. Washington, DC: USAID, Biodiversity Support Program.

Thomas, W. H. (2002). Best Practices in the Use of Indigenous Knowledge. Retrieved from UNESCO/MOST website:

Thomas, W. H. (2008). Finding Common Ground: Birds, Biodiversity and the Implications of Human Activity for Conservation in New Guinea. Environmental Management, 45, 82–92.

Thomas, W. H. (2010). The Forest Stewards: An Innovative Approach to Conserving Cultural and Biological Diversity in the Heart of New Guinea. In K. W. Panemilla, A. B. Rylands, A. Woofter, & C. Hughes (Eds.), Indigenous Peoples and Conservation: From Rights to Resource Management (pp. 269–276). Washington, DC: Conservation International.

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