A Proposed Research Emphasis to Overcome the Limits of Wildlife-Habitat Relationship Studies

In this essay, I develop the idea that studies of wildlife-habitat relationships could do more to advance our understanding of the distribution, abundance, and fitness of wild animals. Contemporary wildlife studies are hampered by at least 2 problems: (1) a lack of progress in ecology, and (2) a confusion of concepts and terms. The plethora of meanings applied to central concepts such as habitat in ecology is inhibiting communication among scientists and between scientists and managers. Standardized, operational definitions of concepts such as habitat are essential if wildlife scientists are to measure similar habitat entities. The habitat concept certainly can be used to develop general descriptors of the distribution of animals. However, we repeatedly fail to find commonalities in defining habitat for most populations across space and time because we usually miss the underlying mechanisms (e.g., size and distribution of prey, forage nutrients, competitive factors) determining occupancy, survival, and fecundity. Habitat per se can provide only a limited explanation of the ecology of an animal. A major problem with focusing on habitat is that, by definition, habitat can remain the same (at least as we typically measure it) while use of niche parameters by an animal within that habitat can change. Habitat usually fails as a predictor of animal performance (e.g., fecundity, fitness) because of our unwillingness to identify constraints on exploitation of critical resources and consideration of critical limiting factors. Thus, I suggest a focus on resources: the basic, fundamental currency that allows individual animals to survive and reproduce. This approach will help us to focus our efforts and advance our understanding of how wild animals respond to variation in resource abundance. To be useful for advancing knowledge, the resource currency must have relevance to the fitness of the animal and be within the animal's perceptive abilities to measure it. Various constraints (i.e., niche parameters) act to reduce the rate of resource consumption and thus per-capita population growth. Therefore, I suggest that researchers and managers concentrate on identifying and analyzing the separate roles of critical resources and the factor(s) constraining their use. We must clearly elucidate and separate resources and constraints if we are to advance and develop reliable knowledge for wildlife management.