White-nose syndrome (WNS) is having an unprecedented impact on hibernating bat populations in the eastern United States. While most studies have focused on widespread mortality observed at winter hibernacula, few have examined the consequences of wing damage that has been observed among those bats that survive hibernation. Given that WNS-related wing damage may lead to life-threatening changes in wing function, we tested the hypothesis that reduced abundance of free-ranging little brown myotis (Myotis lucifugus) with severe wing damage as the summer progresses is due to healing of wing tissue. Photographs of captured and recaptured adult females were examined for wing damage and healing rates were calculated for each category of wing damage index (WDI = 0-3). We found that free-ranging bats with severe wing damage were able to heal to a lower WDI score within 2 weeks. Bats with the most severe wing damage had faster healing rates than did individuals with less damage. We also found a significant relationship between body condition and WDI for adult females captured in the early weeks of the active season. Our results support the hypothesis that some bats can heal from severe wing damage during the active season, and thus may not experience increased mortality associated with reduced functions of wings. We urge researchers and wildlife managers to use caution when interpreting data on WDI to assess the impact of WNS on bat populations, especially during the later months of the active season.
Two‐year‐old red spruce seedlings were exposed to various levels ot ozone, from 0.4 to 3 times ambient levels, in open‐top chambers in Ithaca, NY, USA. Exposures, which varied with changes in day length, commenced on May 30, 1987 and continued until December 14, 1987. Seedling biomass, carbohydrate contents, pigment contents, and rate of electron transport were assessed twice monthly during the fumigation period. Orthogonal quadratic or cubic polynomials were used to model the response through time each variable measured. A one‐way analysis of variance model was fitted to every regression coefficient in each polynomial model to test for ozone effects on seasonal physiological patterns. Ozone did not influence growth, foliar pigment content, foliar starch content, root carbohydrate content, or rate of electron transport. The seasonal change of needle raffinose content differed between exposed to low (0.4 ×, 1×) and high (2×, 3×) ozone levels. There was also a trend towards reduced total soluble sugar content foliage during late autumn in higher ozone treatments.
SUMMARYTwo-year-old red spruce (Picea rubens Sarg.) seedlings were exposed to various levels of ozone, from 0-4 to 3 times ambient levels, in open-top chambers in Ithaca, NY, USA. Exposures, which varied with changes in day length, were from 30 May to 16 December 1987 and 1 June to 1 December, 1988. During the second exposure period, ascorbic acid, total and oxidized glutathione, a-tocopherol, and superoxide dismutase were measured in current and previous year's needles at monthly intervals from May to July, and at bi-weekly intervals from September to December. Orthogonalized polynomials were used to model the response through time of each variable measured. A one-way analysis of variance model was fitted to every regression coefficient in each polynomial model to test for ozone effects on seasonal patterns of antioxidant levels. Ozone influenced seasonal changes in total glutathione, the oxidized/total glutathione ratio, and a-tocopherol in previous years's needles and a-tocopherol and superoxide dismutase in current year's needles. Averaged over the whole growing season, the oxidized/total glutathione ratio and superoxide dismutase showed an ozone treatment effect in both age classes. Mean total glutathione content increased in previous year's needles, but was not influenced by ozone in current year's needles. Mean oxidized glutathione content was higher with ozone exposure in current year's needles, but not in previous year's needles. The role of antioxidants in cold hardiness and ozone detoxification is discussed.
Bat wings are important for thermoregulation, but their role in heat balance during flight is largely unknown. More than 80% of the energy consumed during flight generates heat as a by-product, and thus it is expected that bat wings should dissipate large amounts of heat to prevent hyperthermia. We measured rectal (T(r)) and surface (T(s)) temperatures of Brazilian free-tailed bats (Tadarida brasiliensis) as they emerged from and returned to their daytime roosts and calculated sensible heat transfer for different body regions (head, body, wings, and tail membrane). Bats' T(r) decreased from 36.8°C during emergence flights to 34.4°C during returns, and T(s) scaled positively with ambient temperature (T(a)). Total radiative heat loss from bats was significantly greater for a radiative sink to the night sky than for a sink with temperature equal to T(a). We found that free-ranging Brazilian free-tailed bats, on average, do not dissipate heat from their wings by convection but instead dissipate radiative heat (L) to the cloudless night sky during flight ([Formula: see text] W). However, within the range of T(a) measured in this study, T. brasiliensis experienced net heat loss between evening emergence and return flights. Regional hypothermia reduces heat loss from wings that are exposed to potentially high convective fluxes. Additional research is needed to establish the role of wings in evaporative cooling during flight in bats.
SUMMARYThree-year-old red spruce seedlings were exposed to various concentrations of ozone, from 0-4 to 3 times ambient, for two consecutive growing seasons in open-top chambers in Ithaca, NY, USA, Exposures, which varied with changes in daylength, were from 30 May to 14 December 1987 and 1 June to 1 December 1988, Seedling biomass, foliar pigments and carbohydrate content of roots and shoots were assessed once or twice per month. Tree biomass increased through the summer and declined slightly in late autumn, regardless of" ozone treatment. Biomass and contents of sugar and starch of 1988 fixed growth declined linearly with exposure to increasing levels of ozone. Rates of decline in total shoot biomass and old shoot biomass increased linearly with exposure to increasing concentrations of ozone, but tree height was not affected. Seasonal means of starch content of roots decreased linearly with increasing doses of ozone, but in contrast seasonal mean sugar content and rate of sugar accumulation of roots increased linearly, Chlorophy!! a and chlorophyll b contents were not affected by ozone.These data are consistent with the concept that ozone stress is cumulative, since effects on biomass and carbohydrate content of roots and shoots were not detected after the first year of exposure, but were detected after the second year of treatments. Furthermore, biomass was reduced by ozone only in tissues that were initiated during the first year of exposures and developed during the second year of exposures (1988 fixed grow-th). Key words; Picea rubem, forest decline, ozone, biomass, carbohydrates. Roberts & Blank, 1987;Barnes & Davison, 1988; INTRODUCTION L^^^^ ^, ^^ jgggj Ozone is the most widespread air The dieback of red spruce (Picea rubens Sarg.) at pollutant in the United States and is responsible for high elevation sites in the eastern United States, and major economic losses of crops (Heck et al., 1982, of other species across Central Europe, is thought to 1983). Since ozone concentrations at high elevations, be associated with the interaction of multiple stresses where red spruce trees are dying, are twice those at (Johnson & Siccama, 1983 Blank, 1985; low elevations where crop losses are found (Johnson Rehfuess, 1987;Johnson, Cook & Siccama, 1988, there is a clear need for research on the Air pollution, and in particular, ozone, may pre-effects of ozone on red spruce physiology. In recent dispose trees to injury from naturally occurring studies, exposure to elevated levels of ozone for one stresses such as summer drought, freezing injury and growing season had no effect on photosynthetic rates winter desiccation (Friedland e/a/., 1984; Guderian, or growth of red spruce seedlings (Taylor et al., Kuppers & Six, 1985; McLaughlin, 1985; Brow^n, 1986; Laurence. Kohut & Amundson, 1989;Alscher et al., 1989). Only recently, information has become • Author to whon-i correspondence should be addressed, available on seasonal changes in other parameters 128 R. G. Amundsort and othersthat are necessary to start to assess ...
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