j? К. Case study
K.l. Read the article and answer the questions.
The Importance of Error in Ecology
In the face of declining fish stocks, fisheries managers have been forced to take drastic measures to try and prevent total collapse of certain fish populations (Pikitch et al., 1997).
Such measures include complete bans on fishing, as was done for the cod fishery in the Grand Banks of Newfoundland, or strict quotas that limit intakes, such as those now imposed on fishing vessels in European Union waters. A challenge of management is to provide a buffer for uncertainties to safeguard the future health of populations. Up until now, management has typically aimed to maximize the number of fish caught, while allowing little safety margin for error. In a useful commentary, Paul Dayton argues that appropriate application of available statistical techniques could allow such buffering.The scientific method recognizes two types of error in measurement:
- type I error — the conclusion that there is an effect when there is none;
- type II error — when an impact exists but is not detected.
These types of errors can be illustrated by considering a proposal to restrict trawling in some areas of the Gulf of Maine to protect benthic habitat. Trawling for scallops can destroy benthic habitat as the nets scrape along the sea floor. If the proposal is accepted and trawling is banned, when in fact it has no serious impact, a type I error has been committed. If the proposal is rejected and trawling does result in habitat destruction, then a type II error is made. Current management focuses on reducing type I errors because maximizing fish catch is of primary economic importance. However, scientific advice should be explicit about type II errors also, because the environmental consequences from type II errors are much more serious and take longer to recover from. Type I errors usually result in only short-term economic costs. An understanding of the scientific method can clearly aid in the decision-making process.
K.2. There are two possible ways to correct type II errors:
- prove that environmental degradation has occurred (this assumes that there is no environmental degradation until demonstrated otherwise) before regulating the resource;
- require the exploiters of public nature resources to prove (switching the burden of proof) that they do not cause damage to the resource.
Why do you think it would be difficult to prove environmental degradation in the fishery industry? Is this also the case for other natural resources?
Do you think that the burden of proof must be put on the exploiters of public nature resources? What are the obstacles to enacting such an approach to resource management?