Kerry R. Foresman

Extreme environmental change and evolution: stress-induced morphological variation is strongly concordant with patterns of evolutionary divergence in shrew mandibles

Morphological structures often consist of simpler traits which can be viewed as either integrated (e.g. correlated due to functional interdependency) or non–integrated (e.g. functionally independent) traits. The combination of a long–term stabilizing selection on the entire structure with a short–term directional selection on an adaptively important subset of traits should result in long historical persistence of integrated functional complexes, with environmentally induced variation and macroevolutionary change confined mostly to non–integrated traits. We experimentally subjected populations of three closely related species of Sorex shrews to environmental stress. As predicted, we found that most of the variation in shrew mandibular shape was localized between rather than within the functional complexes; the patterns of integration did not change between the species. The stress–induced variation was confined to non–integrated traits and was highly concordant with the patterns of evolutionary change—species differed in the same set of non–integrated traits which were most sensitive to stress within each species. We suggest that low environmental and genetic canalization of non–integrated traits may have caused these traits to be most sensitive not only to the environmental but also to genetic perturbations associated with stress. The congruence of stress–induced and between–species patterns of variation in non–integrated traits suggests that stress–induced variation in these traits may play an important role in species divergence.

Comparison of proposed survey procedures for detection of forest carnivores

American marten (Martes americana), fisher (M. pennanti), wolverine (Gulo gulo), and lynx (Lynx lynx) are forest carnivores believed threatened by disturbance of late-successional forests. To manage forested ecosystems for these species, effective methods for their detection must be available. Recently, the U.S. Forest Service proposed standardized survey procedures for the detection of forest carnivores; this report presents the first critical assessment of these protocols. We compared dual-sensor remote cameras and soot-coated open and covered track plates in the same study areas over an 8-month period. Of the 4 species targeted by these procedures, we detected 3 (American marten, fisher, wolverine). The remote camera method ranked highest with respect to ease of use, effectiveness, and accuracy of identifications. However, track plates performed well for 2 species and, under certain circumstances, may be the method of choice. We suggest improvements for each method and encourage that such standardized procedures be applied over wide regions.

Win-Win for Wind and Wildlife: a Vision to Facilitate Sustainable Development

Wind energy offers the potential to reduce carbon emissions while increasing energy independence and bolstering economic development. However, wind energy has a larger land footprint per Gigawatt (GW) than most other forms of energy production, making appropriate siting and mitigation particularly important. Species that require large unfragmented habitats and those known to avoid vertical structures are particularly at risk from wind development. Developing energy on disturbed lands rather than placing new developments within large and intact habitats would reduce cumulative impacts to wildlife. The U.S. Department of Energy estimates that it will take 241 GW of terrestrial based wind development on approximately 5 million hectares to reach 20% electricity production for the U.S. by 2030. We estimate there are ∼7,700 GW of potential wind energy available across the U.S., with ∼3,500 GW on disturbed lands. In addition, a disturbance-focused development strategy would avert the development of ∼2.3 million hectares of undisturbed lands while generating the same amount of energy as development based solely on maximizing wind potential. Wind subsidies targeted at favoring low-impact developments and creating avoidance and mitigation requirements that raise the costs for projects impacting sensitive lands could improve public value for both wind energy and biodiversity conservation.

Evolution of Morphological Integration. I. Functional Units Channel Stress-Induced Variation in Shrew Mandibles

Stress‐induced deviations from normal development are often assumed to be random, yet their accumulation and expression can be influenced by patterns of morphological integration within an organism. We studied within‐individual developmental variation (fluctuating asymmetry) in the mandible of four shrew species raised under normal and extreme environments. Patterns of among‐individual variation and fluctuating asymmetry were strongly concordant in traits that were involved in the attachment of the same muscles (i.e., functionally integrated traits), and fluctuating asymmetry was closely integrated among these traits, implying direct developmental interactions among traits involved in the same function. Stress‐induced variation was largely confined to the directions delimited by functionally integrated groups of traits in the pattern that was concordant with species divergence—species differed most in the same traits that were most sensitive to stress within each species. These results reveal a strong effect of functional complexes on directing and incorporating stress‐induced variation during development and might explain the historical persistence of sets of traits involved in the same function in shrew jaws despite their high sensitivity to environmental variation.

Evolution of morphological integration : Developmental accommodation of stress-induced variation

Extreme environmental change during growth often results in an increase in developmental abnormalities in the morphology of an organism. The evolutionary significance of such stress‐induced variation depends on the recurrence of a stressor and on the degree to which developmental errors can be accommodated by an organism’s ontogeny without significant loss of function. We subjected populations of four species of soricid shrews to an extreme environment during growth and measured changes in the patterns of integration and accommodation of stress‐induced developmental errors in a complex of mandibular traits. Adults that grew under an extreme environment had lower integration of morphological variation among mandibular traits and highly elevated fluctuating asymmetry in these traits, compared to individuals that grew under the control conditions. However, traits differed strongly in the magnitude of response to a stressor—traits within attachments of the same muscle (functionally integrated traits) had lower response and changed their integration less than other traits. Cohesiveness in functionally integrated complexes of traits under stress was maintained by close covariation of their developmental variation. Such developmental accommodation of stress‐induced variation might enable the individual’s functioning and persistence under extreme environmental conditions and thus provides a link between individual adaptation to stress and the evolution of stress resistance.

Stress and Developmental Stability: Vegetation Removal Causes Increased Fluctuating Asymmetry in Shrews

Environmental stress can increase phenotypic variation in populations by affecting developmental stability of individuals. While such increase in variation results from individual differences in ability to buffer stress, groups of individuals and different traits may have different sensitivity to stressful conditions. For example, the sex that is under stronger directional selection for faster growth may be more sensitive to stressful conditions during development. On an individual level, stress-induced variation in a trait may be related to the strength of stabilizing selection that acts on the trait. We experimentally examined sensitivity of mandibular development to stress in a free-living population of common shrews (Sorex cinereus), a short-lived insectivore mammal with very limited dispersal and nearly continuous foraging activity. We found a strong increase in asymmetry in shrews born under stressful conditions. Increased asymmetry was associated with lower physiological condition in both control a...

Low Genotyping Error Rates and Noninvasive Sampling in Bighorn Sheep

Abstract Noninvasive DNA sampling allows studies of natural populations without disturbing the target animals. Unfortunately, high genotyping error rates often make noninvasive studies difficult. We report low error rates (0.0–7.5%/locus) when genotyping 18 microsatellite loci in only 4 multiplex polymerase chain reaction amplifications using fecal DNA from bighorn sheep (Ovis canadensis). The average locus-specific error rates varied significantly between the 2 populations (0.13% vs. 1.6%; P < 0.001), as did multi-locus genotype error rates (2.3% vs. 14.1%; P < 0.007). This illustrates the importance of quantifying error rates in each study population (and for each season and sample preservation method) before initiating a noninvasive study. Our error rates are among the lowest reported for fecal samples collected noninvasively in the field. This and other recent studies suggest that noninvasive fecal samples can be used in species with pellet-form feces for nearly any study (e.g., of population structure, gene flow, dispersal, parentage, and even genome-wide studies to detect local adaptation) that previously required high-quality blood or tissue samples.

WHEN REINTRODUCTIONS ARE AUGMENTATIONS: THE GENETIC LEGACY OF FISHERS (MARTES PENNANTI) IN MONTANA

Abstract Fishers (Martes pennanti) were purportedly extirpated from Montana by 1930 and extant populations are assumed to be descended from translocated fishers. To determine the lineage of fisher populations, we sequenced 2 regions of the mitochondrial DNA genome from 207 tissue samples from British Columbia, Minnesota, Wisconsin, and Montana. In northwestern Montana, fishers share haplotypes with samples from the upper Midwest and British Columbia; in west-central Montana, we detected haplotypes found in British Columbia samples, but also detected a control region and cytochrome-b haplotype not found in source populations. Based on the unique haplotypes found in west-central Montana, we propose that individuals with these haplotypes are descended from a relic population. Fishers in northwestern Montana are likely descended from fishers from the Midwest and British Columbia.

No Evidence of Persistent Yersina pestis Infection at Prairie Dog Colonies in North-Central Montana

Sylvatic plague is a flea-borne zoonotic disease caused by the bacterium Yersinia pestis, which can cause extensive mortality among prairie dogs (Cynomys) in western North America. It is unclear whether the plague organism persists locally among resistant host species or elsewhere following epizootics. From June to August 2002 and 2003 we collected blood and flea samples from small mammals at prairie dog colonies with a history of plague, at prairie dog colonies with no history of plague, and from off-colony sites where plague history was unknown. Blood was screened for antibody to Y. pestis by means of enzyme-linked immunosorbent assay or passive hemagglutination assay and fleas were screened for Y. pestis DNA by polymerase chain reaction. All material was negative for Y. pestis including 156 blood samples and 553 fleas from colonies with a known history of plague. This and other studies provide evidence that Y. pestis may not persist at prairie dog colonies following an epizootic.

Efficacy of translocations for restoring populations of black-tailed prairie dogs

Abstract We evaluated translocation as a method to promote recovery of black-tailed prairie dogs (Cynomys ludovicianus) after plague-induced population declines in colonies at the Charles M. Russell National Wildlife Refuge, Montana. We translocated prairie dogs in June of 1999 and evaluated the effects of translocation on colony area 1 year and 4 years later. We also assessed effects of release group size and estimated rates of population growth and survival. Initial size of experimental colonies was categorized as inactive (0 ha), small (0.1–2.0 ha), or large (2.0–6.6 ha); numbers of prairie dogs translocated to each colony size class were 0 (control), 60, and 120. Among inactive colonies, the control remained inactive and the colony receiving 60 prairie dogs grew to 1.5 ha by 2000 and after a second release in 2002 was 1.9 ha in 2003. The colony receiving 120 grew to 3.3 ha by 2000 and decreased to 2.6 ha by 2003. Patterns on small and large colonies after 1 year were less dramatic, but in each case the proportional increase in colony area was lowest on the control and highest on the colony receiving 120 prairie dogs. Patterns were more difficult to discern 4 years after translocations. It appears that as large colonies approach historic size, area growth decreases and is slower than on small colonies. Experimental colonies grew 24.6 ha (315%) by 2000 and 72.1 ha (924%) in 4 years compared to non-experimental colonies of similar size that grew 6.5 ha (23%) in 1 year and 26.5 ha (93%) by 2003. Monthly survival rates of prairie dogs during the first 3 months following translocation were higher on large colonies (0.79, 95% CI=0.75–0.82) than on small (0.67, 95% CI=0.62–0.72) or inactive colonies, (0.63, 95% CI=0.57–0.68). Monthly survival rates were relatively high (0.88–1.0) during subsequent intervals and did not vary among initial colony size classes. Recapture rates for all colonies were higher during the fall trapping session (0.83, 95% CI=0.76–0.90) than in the winter (0.59, 95% CI=0.49–0.69). Translocation was effective for restoration of prairie dog populations, particularly on inactive colonies.