Declines in summer bat activity in central New England 4 years following the initial detection of white-nose syndrome

White-nose syndrome (WNS) was first reported in a hibernating bat population in central New York State in February 2006. Since 2006, WNS has been reported from bat hibernacula across much of eastern United States and adjacent Canada and has been associated with a dramatic decline in the populations of hibernating bats in the northeastern U.S. We are only beginning to discover how these declines are manifest in changes in summer bat abundance and activity at local scales. A 3-year (2004–2006) acoustic survey showed that the forested watershed of the Quabbin Reservoir in central Massachusetts supported an abundant and species-rich summer bat community. In 2010, 4-years following the initial occurrence of WNS, a re-survey of the same habitats and sites found a 72% reduction in bat activity on the watershed. This is the identical rate of decline reported from cave hibernacula surveys (73%). This decline in summer activity levels is most likely a consequence of WNS-caused mortality. The impacts of population losses of this magnitude of a once widespread and abundant taxa are unknown but are presumed to be ecologically significant.     

CAUSES OF DECREASES IN PRODUCTIVITY IN UNDISTURBED TALL GRASS PRAIRIE

There is abundant evidence that protection of the tall grass prairie from grazing, mowing, or burning for even a few years results in accumulation of much litter and reduced productivity. This reduced productivity has been attributed primarily to either the insulating effect of the litter, a lowered rate of mineral recycling, or a presence of toxins in the litter. Considerable evidence exists in the literature concerning the first suggestion, but no studies have been reported concerning the last two in grasslands. A comprehensive project was conducted during the growing season of 1977 in a tall grass prairie in Oklahoma to investigate the three suggestions. It was clear from our data that increased productivity as a result of mowing and burning was not due to the elimination of toxins nor to an increased rate of turnover of organic matter. Soil moisture stress was greater in the mowed and burned plots than in the controls. Thus, the single factor examined which was consistently different, and likely to explain the increased productivity, was the higher soil temperature in the burned and mowed plots early in the growing season. The four dominant grasses in the study plots are non-Festucoid species which are known to have high optimum temperatures for growth.     

Similar and opposite effects of dibutyryl cyclic AMP and insulin on glucose metabolism in adipose tissue

The effects of N⁶-2′-O-dibutyryl cyclic AMP on glucose metabolism and lipolysis in fragments of rat epididymal adipose tissue were studied. Measurements were made of glucose uptake, conversion of glucose carbon to CO₂ and tissue fatty acids and glyceride-glycerol, lactate production, and glycerol release. Low concentrations of dibutyryl cyclic AMP (0.1–0.5 mM) increased all parameters of glucose metabolism and inhibited glycerol release in tissue from both normally fed and fasted rats. Higher concentrations of dibutyryl cyclic AMP (3–5 mM) diminished glucose utilization and greatly accelerated lipolysis. Insulin, 50 μunits/ml, accelerated glucose metabolism in the presence of either low or high concentrations of dibutyryl cyclic AMP though the effect of insulin was greatly reduced by 3 mM dibutyryl cyclic AMP. Tissue exposed to concentrations of dibutyryl cyclic AMP which inhibited glucose metabolism (5 mM), then rinsed and reincubated without dibutyryl cyclic AMP, displayed increased glucose utilization. The results of these experiments emphasize the need for caution in interpretation of the effects of dibutyryl cyclic AMP on adipose tissue metabolism and the need for further research to elucidate the role of cyclic AMP in the regulation of glucose metabolism.