Thermal constraints and optimization of winter feeding and habitat choice in white-tailed deer

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72577/1/j.1600-0587.1991.tb00640.x.pd

Health effects of acid aerosols formed by atmospheric mixtures.

Under ambient conditions, sulfur and nitrogen oxides can react with photochemical products and airborne particles to form acidic vapors and aerosols. Inhalation toxicological studies were conducted, exposing laboratory animals, at rest and during exercise, to multicomponent atmospheric mixtures under conditions favorable to the formation of acidic reaction products. Effects of acid and ozone mixtures on early and late clearance of insoluble radioactive particles in the lungs of rats appeared to be dominated by the oxidant component (i.e., the mixture did cause effects that were significantly different from those of ozone alone). Histopathological evaluations showed that sulfuric acid particles alone did not cause inflammatory responses in centriacinar units of rat lung parenchyma (expressed in terms of percent lesion area) but did cause significant damage (cell killing followed by a wave of cell replication) in nasal respiratory epithelium, as measured by uptake of tritiated thymidine in the DNA of replicating cells. Mixtures of ozone and nitrogen dioxide, which form nitric acid, caused significant inflammatory responses in lung parenchyma (in excess of effects seen in rats exposed to ozone alone), but did not damage nasal epithelium. Mixtures containing acidic sulfate particles, ozone, and nitrogen dioxide damaged both lung parenchyma and nasal epithelia. In rats exposed at rest, the response of the lung appeared to be dominated by the oxidant gas-phase components, while responses in the nose were dominated by the acidic particles. In rats exposed at exercise, however, mixtures of ozone and sulfuric acid particles significantly (2.5-fold) elevated the degree of lung lesion formation over that seen in rats exposed to ozone alone under an identical exercise protocol

Where to Forage When Afraid: Does Perceived Risk Impair Use of the Foodscape?

The availability and quality of forage on the landscape constitute the foodscape within which animals make behavioral decisions to acquire food. Novel changes to the foodscape, such as human disturbance, can alter behavioral decisions that favor avoidance of perceived risk over food acquisition. Although behavioral changes and population declines often coincide with the introduction of human disturbance, the link(s) between behavior and population trajectory are difficult to elucidate. To identify a pathway by which human disturbance may affect ungulate populations, we tested the Behaviorally Mediated Forage‐Loss Hypothesis, wherein behavioral avoidance is predicted to reduce use of available forage adjacent to disturbance. We used GPS collar data collected from migratory mule deer (Odocoileus hemionus) to evaluate habitat selection, movement patterns, and time‐budgeting behavior in response to varying levels of forage availability and human disturbance in three different populations exposed to a gradient of energy development. Subsequently, we linked animal behavior with measured use of forage relative to human disturbance, forage availability, and quality. Mule deer avoided human disturbance at both home range and winter range scales, but showed negligible differences in vigilance rates at the site level. Use of the primary winter forage, sagebrush (Artemisia tridentata), increased as production of new annual growth increased but use decreased with proximity to disturbance. Consequently, avoidance of human disturbance prompted loss of otherwise available forage, resulting in indirect habitat loss that was 4.6‐times greater than direct habitat loss from roads, well pads, and other infrastructure. The multiplicative effects of indirect habitat loss, as mediated by behavior, impaired use of the foodscape by reducing the amount of available forage for mule deer, a consequence of which may be winter ranges that support fewer animals than they did before development

The enactment of socio-technical transition pathways: a reformulated typology and a comparative multi-level analysis of theGerman and UK low-carbon electricity transitions (1990–2014)

tThis paper aims to make two contributions to the sustainability transitions literature, in particular theGeels and Schot (2007. Res. Policy 36(3), 399) transition pathways typology. First, it reformulates anddifferentiates the typology through the lens of endogenous enactment, identifying the main patternsfor actors, formal institutions, and technologies. Second, it suggests that transitions may shift betweenpathways, depending on struggles over technology deployment and institutions. Both contributions aredemonstrated with a comparative analysis of unfolding low-carbon electricity transitions in Germanyand the UK between 1990–2014. The analysis shows that Germany is on a substitution pathway, enactedby new entrants deploying small-scale renewable electricity technologies (RETs), while the UK is on atransformation pathway, enacted by incumbent actors deploying large-scale RETs. Further analysis showsthat the German transition has recently shifted from a ‘stretch-and-transform’ substitution pathway to a‘fit-and-conform’ pathway, because of a fightback from utilities and altered institutions. It also shows thatthe UK transition moved from moderate to substantial incumbent reorientation, as government policiesbecame stronger. Recent policy changes, however, substantially downscaled UK renewables support,which is likely to shift the transition back to weaker reorientation