The good news: Malthus got it wrong. Human population growth hasn’t outstripped the food supply. The species Homo sapiens has domesticated nature in ways that have yielded, among other things, energy-rich grains and the ability to harvest meat and dairy products at will. But at what cost?
A study published this June in the journal Science sets out to answer that very question. Or rather, while the study acknowledges the tremendous gains from taming landscapes, it calls for scientists to get systematic about trying to understand what the tradeoffs are when it comes to managing ecosystems. The study, “Domesticated Nature: Shaping Landscapes and Ecosystems for Human Welfare,” is co-authored by Peter Kareiva, who directs the conservation science program for SCU’s Environmental Studies Institute (ESI), and Sean Watts, who also teaches in ESI, in collaboration with researchers from the Nature Conservancy and Harvard University.
Up until now, the study notes, conservationists have relied on “protecting nature from people as the primary form of stewardship.” But put this together with the fact that only 17 percent of the Earth remains “untouched”—along with the recognition that thousands of years of human activity even in so-called “virgin” rainforests should lead us to rethink our terminology—and you have an approach to stewardship set up for failure. The study also notes, “Apart from reproduction, the most natural of all human activities may be the domestication of nature.”
Yet domestication may give birth to a cascade of unintended crises. For example, humans have mostly eradicated cougars from parts of Utah’s Zion National Park. That’s good for hikers, and good for mule deer—too good, in fact. The deer population has exploded, leading to overgrazing, which, in turn, has exacerbated streambank erosion, increasing sedimentation of streams that is harmful to fish. Plus, deer overpopulation can lead to deer starvation.
On a larger scale, development of levees and channels might protect farmlands and urban areas, but this can lead to loss of wetlands where rivers meet the sea. That’s not just bad for cranes and cattails; when extreme weather hits, the wetlands’ inability to absorb storm surges is acutely felt by humans as well (cf. Katrina).
Ultimately, at stake are social as well as scientific questions. Kareiva, Watts, and their co-authors suggest that resilience theory, “which suggests a link between simplified ecosystems and a loss of resilience,” might help provide a basis for understanding the consequences of choices in managing ecosystems. The goal? A planet where “nature and people simultaneously thrive.” As opposed to one where the ecosystem is pushed beyond the point of no return.
Genetically modified sustainable agriculture?
First there’s the matter of trust in public institutions and agribusiness. Then there’s the question of personal values: For some, it’s a given that pesticides are bad for the environment and that biotechnology is gene splicing us toward a future of frankenfoods with unforetold consequences for biodiversity and human health. Perhaps lost along the way is a hard look at the scientific research itself as to what the ecological consequences are of genetically modified (GM) crops.
Enter a study published this June in Science looking at the data on harms and possible benefits of crops modified to carry the Bacillus thuringiensis (Bt) gene, which kills targeted insects. Michelle Marvier ’90, head of Santa Clara’s ESI, led the four-member research team, which included SCU colleague Kareiva; Chanel McCreedy ’05, who began work on the study as an SCU senior and continued as ESI staff; as well as a researcher from the National Center for Ecological Analysis and Synthesis at UC Santa Barbara. Together, the team has done something no other scientists have: analyzed environmental impact data from field experiments all over the world involving corn and cotton with a Bt gene inserted for insecticidal properties. The results have given GM boosters and detractors alike something to chew on.
Compared to chemically sprayed crops, it turns out that GM crops might just be better for the environment. The study is titled “A Meta-Analysis of Effects of Bt Cotton and Maize on Nontarget Invertebrates.” And it finds that the likes of ladybugs, earthworms, and bees all do better with these Bt crops than they do with crops that use large-scale insecticide spraying.
“We carried out this research,” says Marvier, “because we found that most of the studies submitted by industry to the U.S. regulatory bodies (the U.S. Environmental Protection Agency and USDA) had been poorly replicated and therefore could have ‘missed’ important side effects of these crops. We can now answer the question: Do Bt crops have effects on beneficial insects and worms? The answer is that it depends to a large degree upon the type of comparison one makes.”
Case in point: While the good bugs do better with Bt crops than with sprayed crops, they do better still with non-Bt crops that haven’t been sprayed. So what conclusions can be drawn? One, further investigation is necessary—as is understanding that whether you judge technologies “good” or “bad” depends on the goals of your agro-ecosystems.
The study does conclude with one clear assertion: “Regardless of one’s philosophical perspectives on risk assessment for GM crops, enough experimental data has accumulated to begin drawing empirically based conclusions, as opposed to arguing on the basis of anecdote or hand-picked examples.”
—Steven Boyd Saum is managing editor for Santa Clara Magazine