Developing agency guidelines for relocation of species

Background/Question/Methods: Biologists and land managers relocate, stock, and introduce animal (and plant) species to the properties they manage regularly, and have done so for millennia. Whether we are speaking of fully domestic animals and plants, or wildlife intended for harvest, or more sensitive species which we are attempting to help to survive, the results are not always what was intended. Some introductions fail to thrive, while others increase and spread so rapidly that they become invasive. The art of performing an introduction whose results are predictable is far from well understood, and failures of one type or another are regularly more common than successes. Is it, then, reasonably possible to develop procedures and criteria for responsible relocation of species?

Results/Conclusions: Following a survey of more than 400 published studies of relocation projects, a set of recommendations were prepared which identified the most common reasons for failure. These varied with the taxa involved, and included inadequate evaluation of the habitat, lack of understanding why the original species was lost, lack of monitoring of results, and introduction of too few animals to ensure survival. The conclusion of that study was that relocations and introductions should not be taken lightly and considered a simple solution to ecosystem problems. The next step was to develop a set of criteria which should be applied by managers to the relocation/introduction process if their previous analyses continue to suggest that relocations are necessary to meet program objectives. The criteria developed here and recommended for the Army consider innate characteristics of the taxa involved, legal and regulatory constraints, agency policies, and the time and cost investment necessary to ensure success. The resulting process is not unlike an environmental impact statement, where each of several relevant concerns is evaluated in terms of the proposed project, and the results projected to a final decision document. While there may often be overwhelming need for relocation, removal from a construction site is one common example, precautions are included to be careful that short-term objectives do not override potential long term effects. An unsuccessful relocation or introduction may well result in more problems that if the movement were never undertaken in the first place.