For many people, it may seem counterintuitive to think that carnivores play an integral role in maintaining healthy ecosystems because carnivores are dependent on the death of other animals to remain alive. In actuality, the reason why carnivores are so important to ecosystems is because they help regulate the size of other animal populations, which in turn saves a place for many more animal and plant species. One example of the effect of the extirpation of a carnivore species can be seen with the disappearance of the Mexican wolf (Canis lupus) from its historic habitat in northern Mexico. The extirpation of this wolf species has been tied to changes in both vegetation composition and structure, as well as changes in the abundance and species richness of other animals. In a study conducted by the Consultative Subcommittee for the Recovery of The Mexican wolf (funded by the Mexican Ministry of the Environment), thirty field experts from the U.S. and Mexico sought to identify the most suitable areas for the reintroduction of the wolf back into northern Mexico. Results indicated that pine forests and pine-oak forests offer the best habitat quality for the Mexican wolf, while grasslands and shrubland offer the poorest habitat quality.
Because the presence of the Mexican wolf improves the overall health of the ecosystem it lives in, researches sought to find which type of ecosystem would best support the wolves and would give them the highest chance of survival. The researchers split into four teams and identified 6 areas in northern Mexico where the wolves previously lived and could potentially succeed. The researchers then combined maps of vegetation related to wolf occurrence, buffer areas around settlements, and buffer areas around roads to identify the largest patches of the highest habitat quality for the prioritization of areas for potential reintroduction. The researchers also used their data to determine where prey availability and potential social attitudes toward wolf reintroduction should be addressed.
The reason why the introduction of this species back into its historic habitat is considered important is that native carnivores such as the Mexican wolf are “keystone species.” In other words, the wolf historically has played a key role in maintaining the biodiversity of its native habitat. The disappearance of the wolf in the early 1980’s actually triggered a loss of vegetation because the ungulate population growth rate in northern Mexico spiked and overgrazing occurred. The reintroduction of the wolf will hopefully aid in both the recovery of vegetation and in reduction overabundant ungulate individuals. In this way, the researchers hope that the domino effect caused by the wolf species’ disappearnce will be reversed and that ecosystem function returns to what it once was.
Because this project has only just begun and the wolves have not actually been fully reintroduced into Mexico, many challenges lie ahead. The most pressing challenge involves deciding whether reintroduction should occur in the small and limited areas where there is low risk of wolf mortality, or whether reintroduction should occur in larger areas that have a higher wolf mortality risk but can also maintain a larger wolf population size. Only a limited number of wolves have been released into the wild thus far (with varied results), but there are plans to continue the monitored reintroduction of individuals in the near future.
Source:
ARAIZA, M., CARRILLO, L., LIST, R., GONZÁLEZ, C. A. L., MEYER, E. M., MARTÍNEZ-
GUTIÉRREZ, P. G., MOCTEZUMA, O., SÁNCHEZ-MORALES, N. E. and SERVÍN, J.
(2012), Consensus on Criteria for Potential Areas for Wolf Reintroduction in Mexico.
Conservation Biology, 26: 630–637. doi: 10.1111/j.1523-1739.2012.01888.x
Conservation Biology News 