Managing forests to produce a desirable mix of forest resources, including timber products and wildlife species, requires an understanding of how animals respond to habitat in forests. Habitat provided within and among stands (units of homogeneous forest vegetation used as the basis for management) over a landscape (a complex mosaic of interacting patches including forest stands) can have significant effects on the abundance and distribution of animal species. Management strategies aimed at long-term population change are most likely to succeed if they alter habitat quantity, quality, and/or distribution. Knowing how species select habitat can provide clues as to what habitat elements to provide. Habitat elements are those bits and pieces of a forest important to many species, such as vertical structure, dead wood, tree size, plant species, and forage. We will cover these in more detail in Chapter 4.
Habitat selection is a set of complex behaviors that a species has developed among individuals in a population to ensure fitness. These behaviors are often innate and have allowed populations to persist under the variable conditions that occur over time in forests (Wecker 1963). These behaviors have also allowed each species to select habitat in a manner that allows it to reduce competition for resources with other species. So the evolutionary selection pressures on each species, both abiotic and biotic, have led species to develop different strategies for survival that link habitat selection and population dynamics. Some species are habitat generalists, and can use a broad suite of food and cover resources. These species tend to be highly adaptable and occur in a wide variety of environmental conditions. The deer mouse is a species that exemplifies this strategy in that it can be found in all stages of forest development and in many forest types across the United States. Deer mice have high reproductive rates and can demographically take advantage of abrupt increases in food and cover resources (Figure 3.1). This species is also a primary food resource for many forest predators. Hence, providing habitat for deer mice in a forest is quite easy, although they do tend to be more abundant in early successional forests than in late successional forests.