Use of ecological theory for management of nature needs to follow different rules than use of physical theory to build skyscrapers or rockets. Whereas an engineer has a firm concept of stresses in constructing a structure of steel girders or thrust required to carry a rocket payload, an ecologist has nothing comparable. In such cases, the theory can guide insight, but the insight must be tempered by local understanding of how well the organisms in question fit assumptions of relevant models. A manager must also realize that even if a population could in theory be managed for sustainable yield or maintained in habitat fragments of different size, populations might usually be so small that firm estimates and therefore predictions of persistence, extinction, or colonization are infeasible. If a Himalayan valley hosts three snow leopards, a manager of the cats and their prey may benefit from understanding that the local population may disappear and be replaced by other individuals or that the cats may simply trade individuals with other valleys. The capacity to actually estimate turnover on a quantitative basis is quite likely out of reach.

The quest for developing models that are based on larger, rigorous conceptual framework and that can be tested with appropriately sophisticated methodology should be pursued in ecology. We may profit, however, by acknowledging the shortcomings of ecological predictions, and frankly admitting when prediction is inappropriate because theories are insufficient or not appropriate for the targeted conservation practices. Development of predictive capabilities may take time but, as latest fishery science indicates, we are rapidly advancing toward our destinations. For reasons inherent in the field and the nature of nature, resource managers should avoid the pretense of predicting precise population changes. The concept of building resilience into policy to accommodate contingency, error, and chance is an operational approach to using theory for guidance rather than certainty. So, for instance, a general prediction that abundance of edible fish will change the fortunes of whatever game animals are common as indigenous people deplete in the Amazon may be warranted, but a pretense of predicting what each game or fish population will be given exploitation of it by indigenous people is not. Regarding reserve size, a prediction of persistence of animals and plants as a function of size of habitat patches may work well in uninhabited areas, but proximity of human settlements may overshadow it in many places. Contingencies that are not present in armchair models affect both examples.

The gist is not that ecological paradigms are failing, but that expectations of ecology as a science are not realistic in the real world in the same way that physics informs engineering or molecular biology informs medicine. Theory premised on predictions from large numbers is not much used in local situations where numbers of most organisms are low and where contingent effects may be overriding.

According to the passage, which of the following would be true if the described snow leopards were being studied?

A. Predictions of the leopards’ persistence would have to be made on a quantitative basis due to the animals’ small numbers.
B. The ecological paradigm used to make predictions about the leopards would be invalid.
C. Insight about the leopards’ behavior would be more important than selecting a model that emulated their behavior.
D. Individual humans living in the valley would have to be closely monitored.
E. Care would have to be taken so as to avoid disturbing the leopards’ habitat.



In the passage’s final paragraph, the author is primarily concerned with

A. describing the limitations of a method
B. advocating a new ecological model
C. postulating that certain fields of study are supported by related fields
D. arguing that endangered animals are a bigger problem than previously thought
E. dismissing ecology as a science due to its lack of methodological rigor



According to the passage, which of the following circumstances would have the greatest chance of undermining a typical ecological model?

A. The organism being studied populates an area more quickly than anticipated.
B. Humans native to a studied organism’s habitat hunt it more extensively due to poor crop yields.
C. Experimental data is lost due to faulty data storage.
D. Humans native to a studied organism’s habitat migrate to another area.
E. The experimental data gathered from a large fishery is found to be based on faulty methodology.



It can be inferred from the passage that compared to the effect of humans consuming a species, the effect of native animals consuming that species is

A. less likely to influence ecological theorists
B. more applicable to the eventual survival of the species
C. necessary to quantify in order to establish a precise model for the species’ population
D. more important in establishing a workable ecological model for that species
E. less likely to skew more traditional ecological models