Economic Profitability Versus Ecological Entropy*
用一个基于生态学的内生疾病模型，说明农民多种植广泛种植的作物会通过增加新病原体进化的概率产生负外部性，并证明生态熵是衡量作物生态系统抗灾能力的严格指标。
There is a long-standing trade-off in bioculture between concentrating on high-yield varieties and maintaining sufficient diversity to lower the risks of catastrophic infection. The paper uses a simple ecology-based model of endogenous disease to indicate how a local decision to plant more of a widely grown crop creates negative externalities by increasing the probability that new pathogens will evolve to attack the crop globally. Society's basic issue concerns where to locate on an efficiency frontier between economic profitability and a standard formula for ecological entropy-proved here to be a rigorous measure of “generalized resistance” to crop-ecosystem failure.