Habitat associations of the sagebrush lizard (Sceloporus graciosus): Potential responses of an ectotherm to ponderosa pine forest restoration treatments

Little is known about the response of ectotherms to ponderosa pine (Pinus ponderosa) restoration treatments. The ambient body temperature of an ectotherm affects its physiology, development, and behavior. Microhabitat availability and heterogeneity are critical factors in determining which thermoregulation choices are available to a terrestrial ectotherm (Stevenson 1985). Forest restoration treatments (for example, thinning and burning) will alter herpetofauna microhabitats by decreasing tree canopy cover and allowing more sunlight penetration to the forest floor. This change could, depending on the species, have positive or negative effects on the populations of the area. We sampled microhabitat use by Sceloporus graciosus (sagebrush lizards) in northern Arizona at Grand Canyon-Parashant National Monument using standard pitfall-array sampling methodology. Univariate analyses were used to relate lizard abundance to ponderosa pine tree density, percent soil cover, percent rock cover, litter depth, and insect density. In a multivariate analysis, ponderosa pine density (negatively correlated) and bare soil cover (positively correlated) were the best predictors of lizard abundance. Restoration treatments will increase small-scale heterogeneity within S. graciosus territories by increasing accessibility into and out of sunlight. Based on the thermoregulatory demands of this species, these changes should benefit S. graciosus. However, other possible indirect effects of restoration treatments such as increases in predation on lizards (due to greater visibility), as well as changes in food availability, could negatively impact lizard populations. Future research should focus on pre- and postrestoration treatment monitoring of herpetofauna, and on the direct effects of fire on herpetofauna populations within restoration sites

Bird species distributions across woodland canopy structure gradients

The tree canopy characteristics of two broadleaved woods in southern England were quantified in terms of two independent measures of structure, canopy height (calculated using heights ≥ 1 m) and percentage canopy cover (derived using heights 0.90, p < 0.001), there was a positive correlation across bird species between the mean values of canopy height and canopy cover associated with the mapped locations of each species. We suggest that canopy height acts as an effective surrogate of woodland structure and can be applied as a predictor of bird community composition and distribution, at least in lowland British conditions. Species associated with young growth had narrower niche breadths, as measured by differences in canopy height and canopy cover between the two woods, than did species associated with taller canopies. Remote sensing of canopy height potentially offers a simple, effective way of assessing habitat availability for many species, at both woodland and landscape scales. This may be especially relevant for species dependent on highly transient vegetation structures associated with the early pre-canopy closure stages of forest growth

A demonstration of improved constraints on primordial gravitational waves with delensing

International audienceWe present a constraint on the tensor-to-scalar ratio, r, derived from measurements of cosmic microwave background (CMB) polarization B-modes with “delensing,” whereby the uncertainty on r contributed by the sample variance of the gravitational lensing B-modes is reduced by cross-correlating against a lensing B-mode template. This template is constructed by combining an estimate of the polarized CMB with a tracer of the projected large-scale structure. The large-scale-structure tracer used is a map of the cosmic infrared background derived from Planck satellite data, while the polarized CMB map comes from a combination of South Pole Telescope, bicep/Keck, and Planck data. We expand the bicep/Keck likelihood analysis framework to accept a lensing template and apply it to the bicep/Keck dataset collected through 2014 using the same parametric foreground modeling as in the previous analysis. From simulations, we find that the uncertainty on r is reduced by ∼10%, from σ(r)=0.024 to 0.022, which can be compared with a ∼26% reduction obtained when using a perfect lensing template or if there were zero lensing B-modes. Applying the technique to the real data, the constraint on r is improved from r0.05<0.090 to r0.05<0.082 (95% C.L.). This is the first demonstration of improvement in an r constraint through delensing