A study on the declining population of Mexican wolves has added another important factor to consider when putting conservation restoration efforts in place. Researchers at the Kalmath Center for Scientific Research have shown that connectivity between different populations and ease of migration from one to the next should be an important component of restoration of endangered species back into the wild.
The researchers wanted to understand the ways in which animal populations can be sustained for generations after restoration into the wild. They used a computer simulation model called Vortex in which the specified different conditions and distances of populations to come up with a more quantitative way to measure the effects of connectivity.
Vortex, the computer simulation model, uses population viability analysis (PVA), which is a calculation of the probability of survival of a population to the next generation. It then related this to the connectivity of fragmented wolf populations.
The Mexican grey wolf is currently in the process of being restored to the wild after a captive breeding project that yielded about 300 individuals from just 7 original wolves. Because only 75 individuals currently exist in the US wildlife, effective, long term conservation efforts are necessary for the species to survive.
Connectivity between different populations of grey wolves is beneficial due to the opportunity it presents the wolves to interbreed. Interbreeding is beneficial for the population because it provides more genetic variation that allows the following generations to withstand or adapt to a multitude of situations therefore continuing the species for longer.
Inbreeding has many deleterious effects on a population’s litter size. Because most of the captive populations come from 7 individuals, this is a prevalent problem for the Mexican wolves. Additionally, wolf packs have only one alpha male and one alpha female that are typically the ones to reproduce. This further reduces the chances for genetic variation in the population and emphasizes the importance of connectivity between populations.
The main findings of the study were that decreasing dispersal or migration rates increased the risk of extinction of the wolf populations, especially if those populations were small. If the population contained a large number of individuals but less than 150, the rate of extinction of that population was predicted to decrease according to the Vortex model.
Human beings are the main cause of the dwindling wolf populations. From illegal shooting and hunting to vehicle accidents, humans have been responsible for the placement of this species on the endangered species list.
Efforts to restore the captive individuals back into the wild have been successful for now but, as this study predicts, they will require conditions in which the wolves can migrate between populations in one giant metapopulation. This will potentially reduce extinction render the current conservation efforts useful.
The researchers are making a point that this method of quantifying effects of connectivity can be used for any restoration efforts related to conservation and can now be an additional factor to consider when thinking about the sustainability of such efforts.