Reintroduction or Recolonization: Is there a Difference?

In many places throughout the country, wolves are back in their historic habitat, but how did they get there?   When talking about wolves, the terms recolonization and reintroduction may often be confused.

Recolonization is defined as wolves naturally emigrating into a historical former habitat and establishing a territory. The wolf population grows as a result of natural reproduction and dispersal. There is no human intervention in this process. Reintroduction is defined as the release of captive wolves into a historical former habitat with the goal of having them establish a territory. The desired outcome is an increase in population as a result of natural reproduction and dispersal of progeny of the introduced individuals and resultant re-establishment of territory in historical former habitat. However, as this process unfolds, wolves may be brought back into captivity and possibly re-released or other captive wolves may be released depending on the circumstances. There is generally quite a bit of planning and intervention by humans in order for the program to be successful, at least in the initial stages.

An example of recolonization was seen in Glacier National Park in Montana. Gray wolves were eliminated from Montana by the 1930’s. Gray wolves from Canada began to emigrate into Glacier National Park in 1979. The first wolf den in the western United States in over 50 years was discovered in Glacier National Park in 1986. The gray wolf population increased as a result of natural reproduction and dispersal. By 1994 the population was estimated to be 48 wolves.  Another successful example of recolonization is what has happened in the Western Great Lake states, with wolves dispersing from Minnesota into Wisconsin and Michigan.

An example of reintroduction is the population of Mexican wolves currently found in portions of Arizona and New Mexico. Mexican wolves were eliminated from the wild in the United States by 1970, primarily due to an extensive erradication program. Through a carful recovery planning process, 11 captive Mexican wolves were released into the wild by humans in 1998.Over the years, further captive releases occurred to attempt to increase genetic diversity of the wild population, and also augment losses that were occuring in the wild.  In 2008 the wild Mexican wolf population in Arizona and New Mexico was known to be 52. This slight increase in the Mexican wolf population is the result of natural reproduction and dispersal, as well as human intervention through a carefully monitored program.

Secondly, each process has been granted different levels of status of protection, according to the Endangered Species Act.  For instance, naturally, recolonizing populations are generally given full protection as “endangered”, if the species was already listed at that level when they returned.  This is what was afforded the Glacier National Park population, as well as any other wolf that dispersed into the area.  For reintroduction in the Southwester U.S., the Mexican gray wolf was listed as experimental, non-essential population.  This designation was made to allow for more flexible management of the species, especially where wolf-human conflict may arise.  This designation was also made to wolves that were translocated from Canada into Yellowstone National Park and the red wolves in the Alligator River National Wildlife Refuge. 

How becomes a less pressing question for those of us committed to the goal of re-establishing wolves as an integral part of the natural ecosystem in their historic habitat.    The critical question for us is can we succeed in turning opponents to supporters or neutral bystanders as wolves strive to reclaim their place in the wild.