If renewable resources are harvested at a rate greater than their
regeneration rate, the long-term flow of benefits is reduced, and they
are said to be overharvested. When natural capital is drawn down too
far, fundamental ecosystem changes can occur which make ecosystem
recovery to full service delivery potential very slow or impossible,
and degradation is said to have occurred. Degraded ecosystems support
half or less of the biodiversity of non-degraded used ecosystems.
overharvesting is the unintended side effect of activities aimed at
harvesting just one or a few components of the ecosystem. The discarded
“bycatch” in fisheries and the habitat destruction caused by logging
are examples of this. Regulatory policies that pay no heed to anything
other than the target species encourage this kind of damage.
is a problem in many localities. For example, about 9 percent of
rangelands south of the equator are grazed by domestic livestock at
unsustainable rates. The fish stocks in the Great Lakes (Lake Victoria
in particular) show classic symptoms of overfishing, and marine fish
stocks in Western and Eastern Africa are at risk of overfishing.