For example, logging activities can increase the densities of white-tailed deer, moose and wolves. Wolves love the increased access as much as people. Barriers to caribou movements may have long-term harmful effects by isolating populations. Loss of genetic diversity in small populations may reduce fitness-the ability to survive and reproduce. We risk isolating these sub-populations with, as yet, unknown consequences.
Biologists attempt to isolate environmental factors and measure their effect on a population.
However, the interaction of variables is likely to have the largest effect on caribou. For example, global warming can affect the amount of snow and the presence of hard layers in it. This may force caribou into new locations, putting them in contact with wolves, and it can also make them more vulnerable to being caught in a chase. Effects can be subtle. A slight decline in condition can reduce fertility and increase mortality.