SUSTAINABLE EXPLOITATION OF RENEWABLE RESOURCES

Sustainable exploitation of renewable resources depends on the existen ce of a reproductive surplus, which is determined by the balance betwe en births, deaths, and somatic growth. The reproductive surplus differ s spatially and temporally as environmental conditions vary, and even in the absence of exploitation, change is the rule and constancy is th e exception. Sustainable yields may be estimated by direct experimenta tion, observation of natural systems, or deduction from biological und erstanding. Each of these approaches has limitations, and for large-sc ale unique resources, the only way to determine the response of the po pulation to harvesting is by direct exploitation. To find the maximum potential yield, the resource must be overexploited at some time, or v ery similar resources must have been overexploited. Temporal changes i n environmental conditions mean that information on sustainability col lected in the past may have limited applicability in the future. The u nregulated dynamic of exploiters is to push the resources to overexplo itation, and even when regulated, exploiters have been very successful at modifying their behavior so that regulations are less effective th an anticipated. The most successful institutions at maintaining sustai nability have been small-scale community or private ownership.