The Preble’s meadow jumping mouse: subjective subspecies, advocacy and management
M. A. Cronin. 2007. The Preble’s meadow jumping mouse: subjective subspecies, advocacy and management. Correspondence, Animal Conservation 10 (2007) 159–161
Dr. Matthew Cronin, PhD. is Research Associate Professor of Animal Genetics, School of Natural Resources and Agricultural Sciences, University of Alaska Fairbanks. He is also a member of the Alaska Board of Forestry.
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I read with concern the letters to the editor regarding the Preble’s meadow jumping mouse Zapus hudsonius preblei in which Martin (2006) criticized Ramey et al. (2005) for questioning the subspecies designation and the editor for a failed peer review, and Crandall (2006) defended his editorship.
However, the debate over the subspecies status of the Preble’s meadow jumping mouse does not properly acknowledge the subjectivity of the subspecies category. Designation of subspecies status is inherently subjective and this should be openly admitted by both sides of the debate. Accusations of advocacy in this issue are spurious because applied fields such as wildlife conservation or agriculture have inherent advocacy for management objectives. As discussed below, I suggest management units of intraspecific groups should be based on geography, not subjective judgements of subspecies status or genetic differentiation.
The subspecies status of this mouse has been discussed extensively (Ramey et al., 2005, 2006; Crandall, 2006; Martin, 2006; Vignieri et al., 2006) because it has been listed as threatened under the Endangered Species Act (ESA). Briefly, the Preble’s mouse was designated a subspecies with limited descriptive morphological data. There are no diagnostic characters that unequivocally distinguish it from conspecifics. It does not have monophyletic mitochondrial DNA. It may be geographically isolated from, and have different allele frequencies than, con-specific populations. Sample sizes and locations studied are probably small relative to population numbers. The allele frequency differences are for DNA loci that are usually considered selectively neutral. There are no data documenting local adaptation, but it is possible. Given the lack of quantitative criteria for naming subspecies the Preble’s mouse could be considered a legitimate subspecies, or not a legitimate subspecies. My concerns center on the lack of appreciation of the subjectivity of subspecies and on misunderstanding of the nature of advocacy and management in the context of the Preble’s mouse.
It is well established that the subspecies category is subjective (reviewed by Cronin, 1993, 2006; Geist, O’Gara & Hoffmann, 2000; Zink, 2004). This includes other cases involving the ESA (e.g. Cronin, 1997; Zink et al., 2000) and recognition of this could have avoided much of the debate over the Preble’s mouse. …
The subjectivity of subspecies designation is exemplified by the Preble’s mouse. Ramey et al. (2005) used a hypothesis testing approach for genetic, ecological and morphological data and concluded that the subspecies designation was not warranted. Vignieri et al. (2006) presented criteria (no or significantly reduced gene flow), acknowledged subspecies are not well defined, and then concluded the Preble’s mouse is a legitimate subspecies. The ensuing critiques (Crandall, 2006; Martin, 2006; Ramey et al., 2006; Vignieri et al., 2006) demonstrate neither was an absolute result. It is important to recognize that other intra-specific groups that can be listed under the ESA, distinct population segments-DPS and evolutionarily significant units- ESU, are also subjectively defined (Cronin, 2006).
The subjectivity of subspecies should result in scientists agreeing to disagree on designations. However, discussion of the Preble’s mouse subspecies status has degenerated to accusations of ‘advocacy dressed up as science’ (Martin, 2006). Crandall (2006) pointed out that Martin himself was practicing advocacy while accusing Ramey et al. (2005) of practicing advocacy. It is important to note the applicable definition of advocacy: defending or maintaining a cause or proposal (Webster’s Ninth New Collegiate Dictionary). I hope the reader recognizes that conservation biology, conservation genetics, animal conservation and related fields can be construed as advocacy. After all, conservation is a specific cause (or management objective), not a science. One may use science to achieve wildlife conservation, as one would use science to achieve a management objective of agricultural crop production. It is important to recognize that The Wildlife Society and Society for Conservation Biology are composed primarily of scientists, but openly practice advocacy for conservation. Indeed, an issue of TheWildlife Society Bulletin featured policy and advocacy (The Wildlife Society, 1995). To avoid unproductive accusations, we need to recognize that advocating for different management objectives is inherent in applied fields such as in conservation, agriculture, forestry and medicine.
It is also important to recognize the distinction between science and management. Science can be considered as knowledge obtained from observations, measurements and data analyses of the physical world. In the case of the Preble’s mouse, this includes analyses of morphology, range and genetics. Management is what one does to achieve objectives. In this case, some people have management objectives to maximize conservation of the mouse. Others may have objectives that include agriculture, building or other land uses. In either case, science may be used to achieve management objectives. Conservationists may use science to enhance habitat, control predators or implement other measures to manage the mouse population. Others may use science to enhance crop or livestock production. The point is that science is value-neutral and does not necessarily support either conservation or development. …
It is my contention that we should continue the rigorous sciences of systematics, phylogenetics and population genetics, but we should focus management on geography (i.e. management units based on geography; Cronin, 1993, 1997, 2003). That is, for most practical fish and wildlife management applications, the geographic area and the species on it are the primary issue. If Z. hudsonius is desired in a geographic area, then manage for it regardless of its subspecies or genetic status. Although native populationsmay be favored if they are adapted to local conditions, mixing stocks of different geographic origins may also be advantageous because this can enhance genetic variation (Paabo, 2000), and use of non-native stock may be successful if they are ‘ecologically exchangeable’ (Crandall et al., 2000). In the case of Z. hudsonius, there is no indication that populations from different areas are not ecologically exchangeable (Ramey et al., 2005).
Interestingly, my proposal to base fish and wildlife management on geography was preceded by Wilson & Brown’s (1953) common sense taxonomic suggestion of simply using the Latin binomial species name with the locality or geographic range instead of subjective trinomial subspecies names. That is, for management and intra-specific classification, the species and geographic location are the primary units of concern and they can usually be defined in an objective, empirical manner. I recognize that some species designations are questionable (see Baker & Bradley, 2006), but for most management applications species identity is not a problem. From this point of view, if the time and money spent on Z. hudsonius subspecies, genetic studies, debate, meetings, committees, travel, phone calls and lawyers was spent on purchasing habitat, giving landowners incentives to enhance or maintain habitat, and trans-locating mice to vacant habitat, there probably would not be a Preble’s mouse problem at all.
