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The Scientific Basis for Conserving Forest

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The Scientific Basis for Conserving Forest Chapter 7 Information Needs and a Research Strategy for Conserving Forest Carnivores Leonard F. Ruggiero, USDA Forest Service, Rocky Mountain Forest and Range Experiment Station, Laramie, Wyoming Steven W. Buskirk, Department of Zoology and Physiology, University of Wyoming, Laramie, Wyoming Keith B. Aubry, USDA Forest Service, Pacific Northwest Research Station, Olympia, Washington L. Jack Lyon, USDA Forest Service, Intermountain Research Station, Missoula, Montana William J. Zielinski, USDA Forest Service, Pacific Southwest Research Station, Arcata, California INTRODUCTION Research that addresses information needs usually cannot be generalized for the entire range of a spe- This forest carnivore conservation assessment sum- cies. Populations within species may be unique in marizes what is known about the biology and ecol- their genetic or acquired attributes, thus represent- ogy of the American marten, fisher, lynx, and wol- ing important elements of variability that must be verine. It is the first step in ascertaining what infor- maintained as part of any sound conservation strat- mation we need to develop a scientifically sound strat- egy (see Chapter 5 for additional discussion). Such egy for species conservation. Although this assessment variation occurs as ecotypic adaptations to the dif- implies that we know what information we need to ferent environments inhabited by populations prescribe necessary and sufficient conservation mea- throughout the range of the species. It follows that sures, the concepts of conservation biology used here the range of behavioral variation exhibited by a spe- give us a better basis for identifying "necessary" infor- cies is not necessarily the same as the range of be- mation than for identifying "sufficient" information. havioral variation exhibited by populations within Thus, we are cautious in defining information needs species. Thus, it is inappropriate to attribute the char- for the development of conservation strategies. acteristics of a widely distributed species to any given In this chapter, we define the categories of infor- population. It is therefore ecologically naive and risky mation that are prerequisite to developing conser- to generalize the results of studies conducted in one vation strategies. We then discuss conceptual issues portion of a species' range to much different envi- that relate to design and the reliability of research ronments in other portions of the range. results within each category. We do this not only as a One solution to this problem is to define land units basis for our research recommendations, but to pro- that may influence behavior and population phenom- vide the reader with information for use in evaluat- ena in some consistent and potentially unique fash- ing available literature and, hence, our existing ion. Such a land stratification must be based on eco- knowledge base. For each category of needed infor- logically important characteristics (e.g., physiogra- mation, we also present specific information needs, phy, vegetation, and climate). We have adopted the provide a rationale for each need, and identify com- classification scheme of Demarchi (Appendix A) for monalities among species when possible. this purpose, and we use this framework to define 138 land units within which studies should be replicated base for developing conservation strategies for for- in order to make geographically relevant and scien- est carnivores in the western United States is ex- tifically reliable inferences about populations. tremely limited. Examination of the summary tables The following categories of information needs are presented in each species chapter reveals that our addressed in this chapter: habitat requirements at entire knowledge base on wolverine ecology in the multiple scales; community interactions; movement western United States comes from one study. The ecology; population ecology and demography; and comparable number for lynx is five and for fisher, behavioral ecology. In our discussion, we emphasize four. Moreover, some of the publications listed in populations as the appropriate level of ecological or- table 1 resulted from studies that were conducted on ganization for making scientific inferences about the same study area at different times by a series of habitat requirements (for reasons discussed above investigators, often graduate students. Thus, much and in Ruggiero et al. 1988). However, such infer- of the knowledge we have is a product of relatively ences are based on research designs that sample the short-term research conducted by inexperienced sci- responses of individual animals within available entists with modest amounts of money and field as- habitats. Thus, our references to the habitat require- sistance. This situation adds to concerns about the ments of populations and species are predicated on nature of our existing knowledge base when one con- sampling the range of variation in the habitat selec- siders that forest carnivores are rather long-lived and tion patterns of individuals. studying them is extremely labor-intensive. In all cases, our use of the term "habitat" refers to a vegetation community without implying use by the animals in question. We use the term "stand" in the INFORMATION NEEDS context of habitat for highly mobile carnivores, and, by definition, a stand is always smaller than a home Information needs are a function of extant knowl- range for any of the species in question. Finally, we edge, and we have a great deal to learn. We describe define the term "landscape" to denote a geographic the information needed to develop conservation area approximately equal in size to x times the me- strategies in the following sections. Our recommen- dian home range size for males of the species in ques- dations about information needs are based on the tion. Thus, landscapes are not fixed entities; rather, they expert opinions of the species-chapter authors and are defined relative to the mobility of the species in on our interpretations of the existing scientific basis question. For analytical purposes, landscapes are to be for species conservation as presented in the species nested within ecologically meaningful bounds (e.g., chapters and elsewhere. The amount of detail we physiographic features corresponding to watersheds) provide in identifying these needs varies among infor- whenever possible. mation types and reflects the state of knowledge; rela- tively well-developed areas of knowledge permit us to OVERVIEW OF EXISTING KNOWLEDGE be more specific about information needs than do ar- eas where knowledge is more poorly developed. Most of what we know about forest carnivores (table 1) is based on studies conducted in Canada or Alaska (wolverine and lynx) or in the eastern United Habitat Requirements States (fisher). Relative to the other forest carnivore at Multiple Scales species, we know the most about marten ecology in the western United States. We define habitat requirements as elements of the Most of the publications reported in table 1 ad- environment necessary for the persistence of popula- dressed multiple topics. Thus, the total number of tions over ecologically meaningful periods of time publications (roughly equivalent to independent (Ruggiero et al. 1988). For the conservation of forest studies) is small relative to the total number of pub- carnivores, habitat requirements must be described lications shown in the body of the table for each spe- in terms of the kinds, amounts, and arrangements of cies. Our knowledge base is more a product of the environments needed to ensure population persis- number of independent studies than of the number tence. This set of conditions should be described at of topics addressed per study. With this in mind, an multiple ecological scales and for all geographic ar- examination of table 1 reveals that our knowledge eas of concern. 139 Conceptual Issues at the stand, home range, landscape, physiographic Patterns of habitat use are generally used to assess province (e.g., ecoprovince), and regional scales and habitat requirements. However, patterns of use may in the context of seasonal, yearly, and longer time differ when considered from different spatial or tem- frames. Some combinations of these factors (e.g., poral perspectives. As examples, patterns of habitat habitat amounts at the regional scale viewed in the use may vary as environmental conditions change context of seasonal variation) may be less important over time (temporal perspective), and the spatial con- than others, but we still must contend with a com- text within which stands occur may reveal crucial plex set of considerations when asking questions information about the use or non-use of stands (spa- about habitat requirements. tial perspective). Because of this, we emphasize is- Habitat Kind(s).-The kinds of habitats required sues of scale and spatio-temporal variability in habi- by populations and species refers primarily to veg- tat relationships. Failure to address or account for etation communities (in some ecological context) and such variability can undermine the reliability of re- their associated structural and compositional at- search results. Accordingly, questions about kinds, tributes. At the stand level, information is needed amounts, and arrangements of environments re- about the kind (type) of vegetation community rep- quired by populations and species should be asked resented and its structural and compositional char Table l.--Numbers of publications of original data dealing with free-ranging
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