A Hierarchical Model for Estimating Change in American Woodcock Populations

Abstract The Singing-Ground Survey (SGS) is a primary source of information on population change for American woodcock (Scolopax minor). We analyzed the SGS using a hierarchical log-linear model and compared the estimates of change and annual indices of abundance to a route regression analysis of SGS data. We also grouped SGS routes into Bird Conservation Regions (BCRs) and estimated population change and annual indices using BCRs within states and provinces as strata. Based on the hierarchical model–based estimates, we concluded that woodcock populations were declining in North America between 1968 and 2006 (trend = −0.9%/yr, 95% credible interval: −1.2, −0.5). Singing-Ground Survey results are generally similar between analytical approaches, but the hierarchical model has several important advantages over the route regression. Hierarchical models better accommodate changes in survey efficiency over time and space by treating strata, years, and observers as random effects in the context of a log-linear model, providing trend estimates that are derived directly from the annual indices. We also conducted a hierarchical model analysis of woodcock data from the Christmas Bird Count and the North American Breeding Bird Survey. All surveys showed general consistency in patterns of population change, but the SGS had the shortest credible intervals. We suggest that population management and conservation planning for woodcock involving interpretation of the SGS use estimates provided by the hierarchical model.     

NIACIN AND NIACINAMIDE ACCUMULATION BY RABBIT BRAIN SLICES AND CHOROID PLEXUS IN VITRO

The transport into and release of¹⁴C-labeled niacin and niacinamide from rabbit brain slices and isolated choroid plexuses were studied. In vitro, both brain slices and choroid plexus concentrated ¹⁴C by specific, energy-dependent mechanisms when [¹⁴C]niacinamide was added to the incubation medium. The saturable accumulation velocities, which were linear for 30 min, depended, in part, on incorporation of the [¹⁴C]niacinamide into NAD. The X_T and Y_max for ¹⁴C accumulation with [¹⁴C]niacinamide in the medium by brain slices and choroid plexus were 0.80 μM and 1.45 μmolkg^?1 (30 min)^?1, and 0.23 μM and 18.6 μmol kg^?1 (30 min)^?1 respectively. In vitro, the choroid plexus, unlike brain slices, vigorously concentrated ¹⁴C by a separate, specific energy-dependent process when ¹⁴C niacin was added to the incubation medium. The saturable accumulation velocity, which was linear for 30 min, depended completely on the metabolism of [¹⁴C]niacin. The K_T and Y_max for¹⁴C accumulation by choroid plexus with [¹⁴C]niacin in the medium were 18.1 μM and 439 μmol kg^?1 (30 min)^?1 respectively. Whether preincubated in [¹⁴C]niacin or [¹⁴C]niacinamide, choroid plexus released predominantly [¹⁴C]niacinamide.     

Soil carbon storage under simulated climate change is mediated by plant functional type

The stability of soil organic matter (SOM) pools exposed to elevated CO₂ and warming has not been evaluated adequately in long‐term experiments and represents a substantial source of uncertainty in predicting ecosystem feedbacks to climate change. We conducted a 6‐year experiment combining free‐air CO₂ enrichment (FACE, 550 ppm) and warming (+2 °C) to evaluate changes in SOM accumulation in native Australian grassland. In this system, competitive interactions appear to favor C₄ over C₃ species under FACE and warming. We therefore investigated the role of plant functional type (FT) on biomass and SOM responses to the long‐term treatments by carefully sampling soil under patches of C₃‐ and C₄‐dominated vegetation. We used physical fractionation to quantify particulate organic matter (POM) and long‐term incubation to assess potential decomposition rates. Aboveground production of C₄ grasses increased in response to FACE, but total root biomass declined. Across treatments, C : N ratios were higher in leaves, roots and POM of C₄ vegetation. CO₂ and temperature treatments interacted with FT to influence SOM, and especially POM, such that soil carbon was increased by warming under C₄ vegetation, but not in combination with elevated CO₂. Potential decomposition rates increased in response to FACE and decreased with warming, possibly owing to treatment effects on soil moisture and microbial community composition. Decomposition was also inversely correlated with root N concentration, suggesting increased microbial demand for older, N‐rich SOM in treatments with low root N inputs. This research suggests that C₃–C₄ vegetation responses to future climate conditions will strongly influence SOM storage in temperate grasslands.     

The analysis of flight paths of male Egyptian cotton leafworm moths, Spodoptera littoralis, to a sex pheromone source in the field

ABSTRACT. The flight of male Spodoptera littoralis (Boisd.) (Noctuidae) towards a pheromone source was recorded during the early part of the night using a cine camera and an image intensifier. The cine films were analysed frame by frame to produce flight tracks from which it was possible to calculate the mean advance rate of moths towards the pheromone source and their projected ground speed, for a series of positions downwind of the source. As wind speed was measured the moth's air speed was also estimated. The moths compensated for changes in wind speed by varying their air speed, hence maintaining a ground speed independent of wind speed. The ground speed itself was found to decrease as moths flew closer to the pheromone source.     

Neuroanatomical Correlates of Hormone Sensitive Behaviors in Frogs and Birds

In this paper I review some aspects of neural and endocrineinteractions in the control of reproductive behaviors of frogsand song birds. In Xenopus laevis, we have shown that castrationwill eliminate a male sex behavior, clasping, and that thisbehavior can be restored by the administration of exogenoustestosterone or dihydrotestosterone but not by estradiol. Thisdifference in hormone action is paralleled by differences inthe locations of androgen and estrogen concentrating cells inthe CNS of Xenopus. Certain brain regions contain autoradiographicallydemonstrable labelled cells only after the administration oftritiated testosterone; others only after estradiol injection.The possibility that label in a third group of nuclei, whichcontain radioactive steroid after either hormone, is due tometabolism of testosterone to estradiol is discussed. Studiesin other anuran species have demonstrated that regions of hormoneuptake are also involved in neural control of frog sex behavior.The song of oscine birds represents another hormone sensitivereproductive behavior whose neural control is probably inlluencedby the activity of hormone concentrating CNS cells. Some ofthe brain nuclei which comprise the efferent pathway for controlof song in the canary have been shown to concentrate tritiatedandrogen in autoradiographic studies on song birds. The uptakeof androgens by medullary motor neurons involved in the controlof reproductively important vocalizations is common to anuransand oscine song birds. Whether this feature of hormone actionon the CNS represents a special feature of the frog and birdbrain or whether the phenomenon may also be present in othervertebrate groups awaits further investigation.     

On the Nature of the External Surface of Cultured Human Embryo Fibroblasts:

Surfaces of human embryo fibroblasts in vitro were reacted with stain and lectin probes for carbohydrate moeities either after or in the absence of treatment with low concentrations of surface-active enzymes and EDTA. Only testicular hyaluronidase significantly suppressed affinity-binding of all three agents, suggesting that acidic glycosaminoglycans are principle components of the cell's exterior.