COUGAR ATTACKS ON HUMANS: AN UPDATE AND SOME FURTHER REFLECTIONS

I examined historical records of unprovoked attacks by cougars on humans in the U.S. and Canada during 101 years (1890-1990). There were 9 attacks resulting in 10 human deaths and at least 44 nonfatal attacks. In a recent paper, I listed these attacks and discussed them in considerable detail (Beier 1991). Although extremely rare, attacks on humans have increased markedly in the last 2 decades, during which cougar numbers and human use of cougar habitats have increased. There is no substantial evidence that habituation underlies this increase in attacks. The data provide weak support for the notion that an attacking cougar may be disposed to attack humans again. Warnings apparently do not deter people from visiting parks in cougar habitat

Comparing linkage designs based on land facets to linkage designs based on focal species

Least-cost modeling for focal species is the most widely used method for designing conservation corridors and linkages. However, these designs depend on today's land covers, which will be altered by climate change. We recently proposed an alternative approach based on land facets (recurring landscape units of relatively uniform topography and soils). The rationale is that corridors with high continuity of individual land facets will facilitate movement of species associated with each facet today and in the future. Conservation practitioners might like to know whether a linkage design based on land facets is likely to provide continuity of modeled breeding habitat for species needing connectivity today, and whether a linkage for focal species provides continuity and interspersion of land facets. To address these questions, we compared linkages designed for focal species and land facets in three landscapes in Arizona, USA. We used two variables to measure linkage utility, namely distances between patches of modeled breeding habitat for 5–16 focal species in each linkage, and resistance profiles for focal species and land facets between patches connected by the linkage. Compared to focal species designs, linkage designs based on land facets provided as much or more modeled habitat connectivity for 25 of 28 species-landscape combinations, failing only for the three species with the most narrowly distributed habitat. Compared to land facets designs, focal species linkages provided lower connectivity for about half the land facets in two landscapes. In areas where a focal species approach to linkage design is not possible, our results suggest that conservation practitioners may be able to implement a land facets approach with some confidence that the linkage design would serve most potential focal species. In areas where focal species designs are possible, we recommend using the land facet approach to complement, rather than replace, focal species approaches

Cast Out: Vagrancy and Homelessness in Global and Historical Perspective

Throughout history, those arrested for vagrancy have generally been poor men and women, often young, able-bodied, unemployed, and homeless. Most histories of vagrancy have focused on the European and American experiences. Cast Out: Vagrancy and Homelessness in Global and Historical Perspective is the first book to consider the shared global heritage of vagrancy laws, homelessness, and the historical processes they accompanied. In this ambitious collection, vagrancy and homelessness are used to examine a vast array of phenomena, from the migration of labor to social and governmental responses to poverty through charity, welfare, and prosecution. The essays in Cast Out represent the best scholarship on these subjects and include discussions of the lives of the underclass, strategies for surviving and escaping poverty, the criminalization of poverty by the state, the rise of welfare and development programs, the relationship between imperial powers and colonized peoples, and the struggle to achieve independence after colonial rule. By juxtaposing these histories, the authors explore vagrancy as a common response to poverty, labor dislocation, and changing social norms, as well as how this strategy changed over time and adapted to regional peculiarities. Part of a growing literature on world history, Cast Out offers fresh perspectives and new research in fields that have yet to fully investigate vagrancy and homelessness. This book by leading scholars in the field is for policy makers, as well as for courses on poverty, homelessness, and world history. Contributors: Richard B. Allen, David Arnold, A. L. Beier, Andrew Burton, Vincent DiGirolamo, Andrew A. Gentes, Robert Gordon, Frank Tobias Higbie, Thomas H. Holloway, Abby Margolis, Paul Ocobock, Aminda M. Smith, Linda Woodbridgehttps://ohioopen.library.ohio.edu/oupress/1000/thumbnail.jp

Desperately Seeking Stable 50-Year-Old Landscapes with Patches and Long, Wide Corridors

Conservation corridors are a promising intervention to preserve biodiversity, yet most research has explored corridors in a landscape context different from their intended purpose. This Community Page asks readers to help identify landscapes that will help answer the question: Do corridors work

Activity patterns of nesting Mexican spotted owls

We collected 2,665 hr of behavioral information using video surveillance on 19 Mexican Spotted Owl (Strix occidentalis lucida) pairs between 25 April and 26 July 1996, Prey deliveries per day increased as the nesting season progressed, with an average of 2.68 prey deliveries during incubation, 4.10 items during brooding, and 4.51 items during the nestling phase. The highest delivery rates were concentrated between 1-3 hours before sunrise (02:00-05:00) and 1-3 hours after sunset(18:00-21:00). Trip duration during diurnal hours increased 14 fold from incubation through the nestling phase, compared with a 7.2 fold increase during nocturnal hours. Nest bout duration decreased during both diurnal (36%) and nocturnal hours (76%) across the nesting season. Nest attentiveness decreased as the nesting season progressed, from 97% during the incubation phase to 47% during the nestling phase. Owls attended nests at higher rates during diurnal hours than nocturnal hours across all nesting phases. Activity patterns of Mexican Spotted Owls showed marked cyclical changes in response to ecological factors. Fluctuations in nesting behavior were related to changes in nesting phase and time of day

Primordial Germ Cell-Like Cells Differentiated In Vitro from Skin-Derived Stem Cells

Background: We have previously demonstrated that stem cells isolated from fetal porcine skin have the potential to form oocyte-like cells (OLCs) in vitro. However, primordial germ cells (PGCs), which must also be specified during the stem cell differentiation to give rise to these putative oocytes at more advanced stages of culture, were not systematically characterized. The current study tested the hypothesis that a morphologically distinct population of cells derived from skin stem cells prior to OLC formation corresponds to putative PGCs, which differentiate further into more mature gametes. Methodology/Principal Findings: When induced to differentiate in an appropriate microenvironment, a subpopulation of morphologically distinct cells, some of which are alkaline phosphatase (AP)-positive, also express Oct4, Fragilis, Stella, Dazl, and Vasa, which are markers indicative of germ cell formation. A known differentially methylated region (DMR) within the H19 gene locus, which is demethylated in oocytes after establishment of the maternal imprint, is hypomethylated in PGClike cells compared to undifferentiated skin-derived stem cells, suggesting that the putative germ cell population undergoes imprint erasure. Additional evidence supporting the germ cell identity of in vitro-generated PGC-like cells is that, when labeled with a Dazl-GFP reporter, these cells further differentiate into GFP-positive OLCs. Significance: The ability to generate germ cell precursors from somatic stem cells may provide an in vitro model to stud

Inter-Individual Isolation by Distance: Implications for Landscape Genetics

Many approaches to understanding the influence of landscape on gene flow account for isolation by distance, a phenomena where individuals that are closer together are more likely to be more closely related. Most theoretical research has focused on isolation by distance between populations. We simulated the expected isolation by distance patterns between individuals within a finite population and found an asymptotic pattern. New null models are needed in landscape genetic approaches to correctly account for isolation by distance patterns. We will briefly review isolation by distance and discuss the factors (time, variance in dispersal, and mutation rates) influencing isolation by distance patterns. Our results have implications for estimating how difficult it is for animals to move through the landscape

A conditional trophic cascade: Birds benefit faster growing trees with strong links between predators and plants

Terrestrial systems are thought to be organized predominantly from the bottom-up, but there is a growing literature documenting top-down trophic cascades under certain ecological conditions. We conducted an experiment to examine how arthropod community structure on a foundation riparian tree mediates the ability of insectivorous birds to influence tree growth. We built whole-tree bird exclosures around 35 mature cottonwood (Populus spp.) trees at two sites in northern Utah, USA, to measure the effect of bird predation on arthropod herbivore and predator species richness, abundance, and biomass, and on tree performance. We maintained bird exclosures over two growing seasons and conducted nondestructive arthropod surveys that recorded 63652 arthropods of 689 morphospecies representing 19 orders. Five major patterns emerged: (1) We found a significant trophic cascade (18% reduction in trunk growth when birds were excluded) only at one site in one year. (2) The significant trophic cascade was associated with higher precipitation, tree growth, and arthropod abundance, richness, and biomass than other site–year combinations. (3) The trophic cascade was weak or not evident when tree growth and insect populations were low apparently due to drought. (4) Concurrent with the stronger trophic cascade, bird predation significantly reduced total arthropod abundance, richness, and biomass. Arthropod biomass was 67% greater on trees without bird predation. This pattern was driven largely by two herbivore groups (folivores and non-aphid sap-feeders) suggesting that birds targeted these groups. (5) Three species of folivores (Orthoptera: Melanoplus spp.) were strong links between birds and trees and were only present in the site and the year in which the stronger trophic cascade occurred. Our results suggest that this trophic system is predominately bottom-up driven, but under certain conditions the influence of top predators can stimulate whole tree growth. When the most limiting factor for tree growth switched from water availability to herbivory, the avian predators gained the potential to reduce herbivory. This potential could be realized when strong links between the birds and plant, i.e., species that were both abundant herbivores and preferred prey, were present

Wolf, Canis lupus, Den Site Selection in the Rocky Mountains

Because mortality of Wolves, Canis lupus, is highest during the first six months of life, den site selection may affect reproductive success of Wolf populations. We studied fine-scale denning habitat selection (within 100 m of den site) by comparing field-measured characteristics of 22 dens in Idaho, Montana, and Alberta with 22 paired random contrast locations within pack home ranges. In order of importance, Wolves denned in areas with greater canopy cover, hiding cover, herbaceous ground cover, and woody debris, and were closer to water than paired random sites. Thus Wolves may select den sites for physical protection and available water. We also studied coarse-scale denning habitat selection by comparing 35 Wolf dens with 35 paired contrast locations in Idaho, Montana, and Wyoming with respect to six remotely-sensed variables (elevation, slope, coniferous forest cover, solar radiation, distance to water, and distance to roads). Although these variables did not differ (univariate P > 0.10) between den and contrast locations, a Mahalanobis-distance model using four remotely-sensed variables (slope, elevation, coniferous forest cover, and solar radiation) suggested > 85% of dens would occur in potential denning habitat occupying < 12% of the Wolf recovery areas in the northern Rocky Mountains. This model may be useful for identifying likely den locations in areas not yet occupied by Wolves. Wolf core use areas, including den areas, showed higher intensity of use throughout the year when compared to the entire territory

Where to restore ecological connectivity? Detecting barriers and quantifying restoration benefits

Landscape connectivity is crucial for many ecological processes, including dispersal, gene flow, demographic rescue, and movement in response to climate change. As a result, governmental and non-governmental organizations are focusing efforts to map and conserve areas that facilitate movement to maintain population connectivity and promote climate adaptation. In contrast, little focus has been placed on identifying barriers—landscape features which impede movement between ecologically important areas—where restoration could most improve connectivity. Yet knowing where barriers most strongly reduce connectivity can complement traditional analyses aimed at mapping best movement routes. We introduce a novel method to detect important barriers and provide example applications. Our method uses GIS neighborhood analyses in conjunction with effective distance analyses to detect barriers that, if removed, would significantly improve connectivity. Applicable in least-cost, circuit-theoretic, and simulation modeling frameworks, the method detects both complete (impermeable) barriers and those that impede but do not completely block movement. Barrier mapping complements corridor mapping by broadening the range of connectivity conservation alternatives available to practitioners. The method can help practitioners move beyond maintaining currently important areas to restoring and enhancing connectivity through active barrier removal. It can inform decisions on trade-offs between restoration and protection; for example, purchasing an intact corridor may be substantially more costly than restoring a barrier that blocks an alternative corridor. And it extends the concept of centrality to barriers, highlighting areas that most diminish connectivity across broad networks. Identifying which modeled barriers have the greatest impact can also help prioritize error checking of land cover data and collection of field data to improve connectivity maps. Barrier detection provides a different way to view the landscape, broadening thinking about connectivity and fragmentation while increasing conservation options