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321.
Linda A. Joyce Geoffrey M. Blate Steven G. McNulty Constance I. Millar Susanne Moser Ronald P. Neilson David L. Peterson 《Environmental management》2009,44(6):1022-1032
This study explores potential adaptation approaches in planning and management that the United States Forest Service might
adopt to help achieve its goals and objectives in the face of climate change. Availability of information, vulnerability of
ecological and socio-economic systems, and uncertainties associated with climate change, as well as the interacting non-climatic
changes, influence selection of the adaptation approach. Resource assessments are opportunities to develop strategic information
that could be used to identify and link adaptation strategies across planning levels. Within a National Forest, planning must
incorporate the opportunity to identify vulnerabilities to climate change as well as incorporate approaches that allow management
adjustments as the effects of climate change become apparent. The nature of environmental variability, the inevitability of
novelty and surprise, and the range of management objectives and situations across the National Forest System implies that
no single approach will fit all situations. A toolbox of management options would include practices focused on forestalling
climate change effects by building resistance and resilience into current ecosystems, and on managing for change by enabling
plants, animals, and ecosystems to adapt to climate change. Better and more widespread implementation of already known practices
that reduce the impact of existing stressors represents an important “no regrets” strategy. These management opportunities
will require agency consideration of its adaptive capacity, and ways to overcome potential barriers to these adaptation options. 相似文献
322.
323.
324.
Stephen R. Griffiths David B. Donato Graeme Coulson Linda F. Lumsden 《Environmental science and pollution research international》2014,21(12):7263-7275
Wildlife and livestock are known to visit and interact with tailings dam and other wastewater impoundments at gold mines. When cyanide concentrations within these water bodies exceed a critical toxicity threshold, significant cyanide-related mortality events can occur in wildlife. Highly mobile taxa such as birds are particularly susceptible to cyanide toxicosis. Nocturnally active bats have similar access to uncovered wastewater impoundments as birds; however, cyanide toxicosis risks to bats remain ambiguous. This study investigated activity of bats in the airspace above two water bodies at an Australian gold mine, to assess the extent to which bats use these water bodies and hence are at potential risk of exposure to cyanide. Bat activity was present on most nights sampled during the 16-month survey period, although it was highly variable across nights and months. Therefore, despite the artificial nature of wastewater impoundments at gold mines, these structures present attractive habitats to bats. As tailings slurry and supernatant pooling within the tailings dam were consistently well below the industry protective concentration limit of 50 mg/L weak acid dissociable (WAD) cyanide, wastewater solutions stored within the tailings dam posed a minimal risk of cyanide toxicosis for wildlife, including bats. This study showed that passively recorded bat echolocation call data provides evidence of the presence and relative activity of bats above water bodies at mine sites. Furthermore, echolocation buzz calls recorded in the airspace directly above water provide indirect evidence of foraging and/or drinking. Both echolocation monitoring and systematic sampling of cyanide concentration in open wastewater impoundments can be incorporated into a gold mine risk-assessment model in order to evaluate the risk of bat exposure to cyanide. In relation to risk minimisation management practices, the most effective mechanism for preventing cyanide toxicosis to wildlife, including bats, is capping the concentration of cyanide in tailings discharged to open impoundments at 50 mg/L WAD. 相似文献
325.
Tomer J. Czaczkes Linda Schlosser Jürgen Heinze Volker Witte 《Behavioral ecology and sociobiology》2014,68(6):981-988
Ants are key model organisms in the study of navigation and memory formation. Many ants learn food locations very quickly and with high accuracy. But can individual ants learn multiple separate food locations, associate them with a cue, and then correctly recall the food location and navigate towards it when later presented with that cue? In this experiment, we sequentially trained Lasius niger foragers to two scented feeders at either end of a T-maze. The next day, an odour cue corresponding to one of the food sources was presented to the ants in the air, on the substrate and via trophallaxis with nest mates. Trained foragers accurately navigated to the correct side of the T-maze (89 % correct decisions), but only after the first 10 min of testing. This demonstrates the ability of ants to perform associative recall, forming clear associates between odour cues and food locations and using these associations to navigate to food sources. We also found that trained ants in the first 10 min of testing showed no preference for the correct side (57 % correct decisions), which may be related to the motivational state of the ants tested. Ants with different motivational states (whether they are ‘scouting’ or ‘recruited’) made use of route memories in a completely different manner. This highlights the importance of taking account of motivational states when performing behavioural experiments. 相似文献
326.
How Climate and Vegetation Influence the fire Regime of the Alaskan Boreal Biome: The Holocene Perspective 总被引:2,自引:0,他引:2
Feng Sheng Hu Linda B. Brubaker Daniel G. Gavin Philip E. Higuera Jason A. Lynch T. Scott Rupp Willy Tinner 《Mitigation and Adaptation Strategies for Global Change》2006,11(4):829-846
We synthesize recent results from lake-sediment studies of Holocene fire-climate-vegetation interactions in Alaskan boreal
ecosystems. At the millennial time scale, the most robust feature of these records is an increase in fire occurrence with
the establishment of boreal forests dominated by Picea mariana: estimated mean fire-return intervals decreased from ≥300 yrs to as low as ∼80 yrs. This fire-vegetation relationship occurred
at all sites in interior Alaska with charcoal-based fire reconstructions, regardless of the specific time of P. mariana arrival during the Holocene. The establishment of P. mariana forests was associated with a regional climatic trend toward cooler/wetter conditions. Because such climatic change should
not directly enhance fire occurrence, the increase in fire frequency most likely reflects the influence of highly flammable
P. mariana forests, which are more conducive to fire ignition and spread than the preceding vegetation types (tundra, and woodlands/forests
dominated by Populus or Picea glauca). Increased lightning associated with altered atmospheric circulation may have also played a role in certain areas where
fire frequency increased around 4000 calibrated years before present (BP) without an apparent increase in the abundance of
P. mariana. When viewed together, the paleo-fire records reveal that fire histories differed among sites in the same modern fire regime
and that the fire regime and plant community similar to those of today became established at different times. Thus the spatial
array of regional fire regimes was non-static through the Holocene. However, the patterns and causes of the spatial variation
remain largely unknown. Advancing our understanding of climate-fire-vegetation interactions in the Alaskan boreal biome will
require a network of charcoal records across various ecoregions, quantitative paleoclimate reconstructions, and improved knowledge
of how sedimentary charcoal records fire events.
In this paper, charcoal refers to macroscopic (≥180 μm) as opposed to microscopic (< 180 μm) particles unless indicated otherwise.
Radiocarbon ages were converted to calibrated years before AD 1950 using the atmospheric calibration data set (Stuiver et
al. 1998). 相似文献
327.
Sygna Linda Fuglestvedt Jan S. Aaheim H. Asbjørn 《Mitigation and Adaptation Strategies for Global Change》2002,7(1):45-62
This article looks at the ability of Global Warming Potentials (GWPs) towork as indicators of equivalence for temperature development and damagecosts. We look at two abatement scenarios that are equivalent when using100-year GWPs: one scenario reduces short-lived gases, mainly methane(CH4); the other scenario reduces carbon dioxide (CO2).Despite their equivalence in terms of CO2 equivalents, the scenariosdo not result in equal rates or levels of temperature change. The disparitiescontinue as we move further down the chain of causality toward damagecosts, measured either in terms of rate of climate change or level of climatechange. Compared to the CH4 mitigation scenario, the CO2mitigation scenario gives present value costs 1.3 and 1.5 times higher forlevel- and rate-dependent damage costs, respectively, assuming a discountrate of 3%. We also test the GWPs for other time horizons and theconclusions remain the same; using GWP as an index to reflect equivalentclimate effects and damage costs from emissions is questionable. 相似文献
328.
Linda A. Whittingham 《Behavioral ecology and sociobiology》1989,25(1):73-80
Summary The effect of brood size and female nesting status on male parental behavior was investigated in red-winged blackbirds Agelaius phoeniceus using brood size manipulation experiments. Male redwings allocated parental effort on the basis of brood size and nestling age. Males began assisting females only at nests with at least three offspring older than three days. Female nesting status had no singificant influence on male parental care. When females were unable to meet a brood's demand for food, males assisted females with nestling feeding. Females did not reduce the amount of food delivered to nestlings when males assisted. The amount of food brought to nestlings by the male was additional to the amount of food provided by the female. Male assistance increased fledgling success. When female provisioning was sufficient to meet a brood's demand for food males did not assist. The value of male parental care varied inversely with the ability of the female to meet nestling food demands. The ability of unassisted females to provide sufficient food and to raise a brood of nestlings successfully appeared to be influenced by resource abundance. 相似文献
329.
Summary Vocalizations of free-ranging North Atlantic pilot whales were studied in different behavioral contexts to gain insight into the function and biological significance of different sound types. Simple whistles (with no frequency inflections) were heard more frequently when whales were milling, a restful behavior type. During surface active behavior, energetic, often coordinated activity probably representing feeding, many sound types, especially complex whistles (with more frequency inflections) and pulsed sounds, occurred with greater frequency than when this behavior was absent. Greater numbers of most whistle types were produced when whales were spread over a larger area and when more subgroups were present. Thus, in pilot whales, there is a significant relationship between their sounds and their behavior, with vocalizations possibly serving to maintain contact and coordinate movements of the herd.
Offprint requests to: L.S. Weilgart at the current address 相似文献
330.
Boris M. Petrikovsky MD Phd Margaret I. Cuomo Elizabeth P. Schneider Linda J. Wyse Harris L. Cohen Martin Lesser 《黑龙江环境通报》1995,15(9):827-829
The aim was to assess the role that fetal bladder size has in the determination of fetal hydronephrosis. Forty-three fetuses were evaluated for fetal hydronephrosis in the second trimester of pregnancy. Anteroposterior measurements of the renal pelvis were obtained with a full bladder and again when the bladder emptied in each fetus. Statistical analysis was performed using the Spearman rank order correlation coefficient to assess the relationship between bladder status and renal dilation. The anteroposterior size of the fetal renal pelvis diminished from 6.8 ± 1.8 mm on a full bladder scan to 4.5 ± 1.6 mm when the bladder was emptied (P<0.001). Fifty-three per cent of the fetuses whose renal pelvic measurements were 5 mm or more on a full bladder scan had normal-appearing renal pelvises when their bladders emptied. The status of the fetal bladder should be considered when evaluating fetal hydronephrosis. 相似文献