The Ultimate Ecosystem Engineers

Abstract

“E volution helps those who help themselves” is the basic idea behind the concept of niche construction or ecosystem engineering (1). Many animal species attempt to enhance their environments, and humans have been trying to make the world a better place—for themselves—for tens of thousands of years, often with unforeseen consequences. We have long been the ultimate niche constructors in terms of our rich repertoire of ecosystem skills and the magnitude of their impact. Today, as our efforts at ecosystem engineering are beginning to attempt to reduce and reverse human modif ication of environments, interest is also growing across diverse fields (including archaeology, biology, climatology, genetics, and geography) in the origins of human dominance of Earth’s ecosystems. The general concept of niche construction provides an important new window of understanding about how our distant ancestors, through their initial domestication of plants and animals, first gained the ability to significantly alter the world’s environments. Currently, research on domestication is carried out on two largely disconnected scales—at the level of individual plant and animal species to document the “what, when, and where” of domestication worldwide (2), and at a regional or larger scale, to identify causal “macro” variables (such as climate change and population growth) that may account for “why” human societies first domesticated target species (3). The theory of niche construction provides a link between research at these two different scales of analysis by offering insights into the intervening “how” of domestication— the general human behavioral context within which macroevolutionary factors forged new human-plant/animal relationships of domestication. Niche construction or ecosystem engineering activities have been documented in a broad range of different animal species. Beavers, for example, through their treecutting, dam building, and pond-creating efforts, generate new landscapes for themselves and many other species. Such efforts at environmental modification are proposed to play an important if underappreciated role in shaping biotic communities and evolutionary processes (1). Studies of human niche construction have usually concentrated on either a particular form of environmental modification, such as controlled burning of vegetation, or on human intervention in the life cycle of a particular target species. Only recently have regional-scale studies offered a fuller appreciation of the extent to which traditional resource-management strategies involve the coherent and integrated manipulation of a broad range of plants and animals and their habitats (4). Documenting the overall niche construction strategies of past human societies, however, remains a difficult challenge. Archaeological evidence for the management of wild plants (sowing, burning, weeding, irrigation, transplanting, and mulching) provides widely scattered clues to the developmental history of integrated systems of human environmental management. Controlled burning of vegetation to maintain a preferred ecosystem state, for example, is documented throughout the Holocene (the last ~10,000 years) in numerous temperate and tropical environments, and may have been present as early as 55,000 years ago in southern Africa (5). Yet in many world regions, the appearance of domesticated plants and animals in the archaeological record provides the strongest evidence for integrated strategies of ecosystem engineering. A number of different aspects of our current understanding of the initial, worldwide domestication of plants and animals points to domestication taking place within a broader behavioral context of niche construction strategies. The development of such human–target species relationships was not a unique event, limited to a particular time or place. Eight to 10 environmentally and culturally diverse world regions have been identified as likely independent centers of domestication and agricultural origin (2). Each exhibits a distinct sequence of domestication of different species over millennia. Human societies thus domesticated a diverse array of species at different How did human societies initially domesticate plants and animals, and what were the keys to success? The Ultimate Ecosystem Engineers

Cite this paper

@inproceedings{Smith2007TheUE, title={The Ultimate Ecosystem Engineers}, author={Bruce Smith}, year={2007} }