The Fate of Tropical Forests: a Matter of Stewardship

Before I respond to points raised by Schwartzman et al. (this issue), it is important to set the context of the debate. The major questions at issue do not concern parks; they concern the fate of wildlands outside of parks. How can biodiversity conservation be achieved under the rubric of sustainable development outside the context of strict, people-free protected areas? The debate is not over goals but over process, in particular the role to be played by rural and indigenous people as stewards of the land and its natural resources. It should be acknowledged at the outset that the terms of debate are inextricably linked to a particular socioeconomic context. What is possible or practical in one country or region may be difficult or impossible in another. Schwartzman et al. write from the vantage point of Amazonian Brazil. Consequently, their prescriptions and recommendations are highly specific to that context, as are the two land-use categories they extol: indigenous people's reserves and extractive reserves. Brazil is a land of immigrants, newcomers emanating from Europe, Africa, and Asia who have largely ignored or brushed aside the Amazon's indigenous inhabitants in their quests for land and wealth. In the Old World, however, everyone is an "indigenous" inhabitant, so the notion of native peoples' rights takes on a different context and meaning. Similarly, the formal designation of large areas of forest as "extractive reserves" is a singularly New World phenomenon. I agree with Schwartzman et al. that in modern times forest people living with preindustrial technology have generally not exterminated top carnivores and other large animals within the regions they occupy. But that observation should not be taken out of context as a basis for broader claims. First, it is imperative to recall that the contemporary fauna of South America represents only the remnants of a much larger fauna that existed prior to the post-Pleistocene megafaunal "overkill" perpetrated by Clovis hunters (Martin & Klein 1984). The well-documented occurrence of prehistorical overkill in the Americas, Australia, New Zealand, Madagascar, Oceania, and elsewhere should put us on notice that premodern indigenous people have not always been exemplary stewards of biotic resources. Second, much evidence points to the benign coexistence of indigenous people and wildlife in Neotropical forests as a condition deriving from technological limitations and low human population densities (Alvard 1994). Wherever indigenous people have acquired firearms and/or increased in number, depletion of game resources has been the norm (Robinson & Redford 1991; Redford 1992; Peres 1994). For an independent demonstration of this cause-and-effect sequence, one can point to the burgeoning bushmeat trade in Central Africa (McRae 1997). Schwartzman et al. dispute the biodiversity-maintaining role of large predators and other large animals: "Nor does the depletion of large animal populations threaten the majority of the other species that comprise these forests." This statement is a rhetorical assertion that flies in the face of a great deal of scientific evidence to the contrary, much of it published in this journal (e.g., Alverson et al. 1988; Soule et al. 1988; Terborgh 1988; Palomares et al. 1995). It is now well established (although not entirely uncontroversial) that the absence of top predators leads predictably to "mesopredator release" and an overabundance of herbivores (Terborgh et al. 1999). Hyperabundant mesopredators generate a cascading effect in reducing the populations of songbirds and other small vertebrates (Wilcove 1985; Garrott et al. 1993), whereas excess numbers of herbivores can dramatically alter patterns of forest regeneration (Alverson et al. 1994; McShea et al. 1997). Decimation of large vertebrates through overhunting, which has occurred in large portions of the Amazon (Redford 1992; Peres 1999), has other drastic consequences for biodiversity (Dirzo & Miranda 1991). It is thus imprudent to dismiss as inconsequential the effect that even low-density human populations can have on biodiversity via trophic cascades. That said, I nevertheless agree with Schwartzman et al. that granting local people rights to the land is far preferable, for both ethical and conservation reasons, to allowing the land to be overrun by a disorderly invasion of loggers, miners, and ranchers. About this we have no argument. Paper submitted April 6, 2000; revised manuscript accepted May 3, 2000.