Semi-Arid Climates: Their Definition and Distribution

Bailey, Harry P.

doi:10.1007/978-3-642-67328-3_3

Cited by 66 publications

(36 citation statements)

References 13 publications

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“…Despite uncertainty about future changes in precipitation [Christensen et al, 2007], recently some have suggested considerable drier conditions for western North America [Overpeck and Udall, 2010]. Our results suggest that under drier conditions CH 4 uptake in these grassland ecosystems, which occupy roughly 11% of the global land surface [Bailey, 1979], will be more sensitive to elevated CO 2 and warming. …”

Section: Discussionmentioning

confidence: 56%

“…[2] Semiarid grasslands account for approximately 11% of the global land surface [Bailey, 1979] and have been shown to be important sinks of CH 4 on a global scale, removing between 0.5 and 5.6 Tg of CH 4 from the atmosphere each year [Mosier et al, 1991]. Natural seasonal variation in soil moisture strongly modulates biological activity in semiarid grasslands [Huxman et al, 2004;Potts et al, 2006].…”

Section: Introductionmentioning

confidence: 99%

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Elevated CO₂and warming effects on CH₄uptake in a semiarid grassland below optimum soil moisture

Dijkstra

Morgan²,

Fischer

et al. 2011

J. Geophys. Res.

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[1] Semiarid rangelands are a significant global sink for methane (CH 4 ), but this sink strength may be altered by climate change. Methane uptake is sensitive to soil moisture showing a hump-shaped relationship with a distinct optimum soil moisture level. Both CO 2 and temperature affect soil moisture, but the direction of CH 4 uptake response may depend on if the system is below or above the soil moisture optimum. Most climate change studies on CH 4 uptake have been conducted in mesic environments with soil moisture levels typically above optimum, but little is known about responses in drier systems with suboptimal soil water. We studied effects of atmospheric CO 2 (ambient versus 600 ppm), and temperature (ambient versus 1.5/3.0°C warmer day/night) on CH 4 uptake during two growing seasons in a full factorial semiarid grassland field experiment in Wyoming, United States. We observed typical hump-shaped relationships between CH 4 uptake and water filled pore space. Averaged over a range of soil moisture conditions, CH 4 uptake was not affected by elevated CO 2 , but significantly decreased with warming in both seasons (25% in the first and 13% in the second season). Warming showed the strongest reduction and elevated CO 2 showed the strongest increase in CH 4 uptake when soils were below optimum moisture, indicating that these effects are particularly strong when soils are dry. Thus, directional effects of elevated CO 2 and warming on CH 4 uptake in semiarid grasslands can be opposite to their effects in mesic ecosystems because semiarid grasslands are often below optimum soil moisture for methane uptake.Citation: Dijkstra, F. A., J. A. Morgan, J. C. von Fischer, and R. F. Follett (2011), Elevated CO 2 and warming effects on CH 4 uptake in a semiarid grassland below optimum soil moisture,

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Section: Discussionmentioning

confidence: 56%

Section: Introductionmentioning

confidence: 99%

Elevated CO₂and warming effects on CH₄uptake in a semiarid grassland below optimum soil moisture

Dijkstra

Morgan²,

Fischer

et al. 2011

J. Geophys. Res.

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“…The park is located along the Red Deer River in southern Alberta (50°45'09.2"N, 111°31'03.6"W) and represents a mixed landscape of prairie and riparian habitat with an extensive network of creeks and drainages. The semi-arid climate is characterized by hot, dry summers, cold winters, and low overall precipitation (Bailey 1979). At least three species-E. fuscus, western small-footed myotis (M. ciliolabrum (Merriam, 1886)), and western long-eared myotis (M. evotis (Allen, 1864))-over-winter in deep rock crevices in the area (Lausen and Barclay 2006).…”

Section: Study Areamentioning

confidence: 99%

Environmental correlates and energetics of winter flight by bats in southern Alberta, Canada

et al. 2016

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Winter activity of bats is common, yet poorly understood. Other studies suggest a relationship between winter activity and ambient temperature, particularly temperature at sunset.We recorded echolocation calls to determine correlates of hourly bat-activity in Dinosaur Provincial Park, Alberta, Canada. We documented bat activity in temperatures as low as -10.4°C.We observed big brown bats (Eptesicus fuscus (Palisot de Beauvois, 1796)) flying at colder temperatures than species of Myotis bats (genus Myotis (Kaup 1829). We show that temperature and wind are important predictors of winter activity by E. fuscus and Myotis, and that Myotis may also use changes in barometric pressure to cue activity. In the absence of foraging opportunity, we suggest these environmental factors relate to heat loss and thus the energetic cost of flight. To understand the energetic consequences of bat flight in cold temperatures, we estimated energy expenditure during winter flights of E. fuscus and Myotis lucifugus using species-specific parameters. We estimated that winter flight uses considerable fat stores and that flight thermogenesis could mitigate energetic costs by 20% or more. We also show that temperature-dependent interspecific differences in winter activity likely stem from differences between species in heat loss and potential for activity-thermoregulatory heat substitution. IntroductionDuring hibernation, metabolic rate (MR) and body temperature (T b ), are decreased for days to weeks (Ruf and Geiser 2015). Hibernating animals save considerable energy and can survive on limited resources (i.e., body fat or cached food) for extended periods, up to months at a time (Humphries et al. 2003). Benefits of hibernation are obvious (Geiser 2004;Geiser and Brigham 2012) but there are associated costs, such as suppressed molecular synthesis (Lillegraven et al. 1987), ceased or delayed reproduction (Racey 1969; Barnes et al. 1986), and immunosuppression (Bouma et al. 2010). For these reasons and likely others, nearly all hibernating mammals arouse periodically (Willis 1982; French 1985), ostensibly to excrete metabolic wastes (Baumber et al. 1971), mount immune responses (Burton and Reichman 1999), mate (Thomas et al. 1979), eat (Humphries et al. 2001), and possibly drink (Thomas and Cloutier 1992;Thomas and Geiser 1997; Ben-Hamo et al. 2013).Much of what we know about arousals and winter activity of temperate-zone bats comes from research on caverniculous species. In eastern North America, bats often roost in large groups in sizeable, humid, thermally-stable hibernacula (Webb et al. 1996;Perry 2012). Most activities typical of arousals occur within the hibernacula; caves and mines allow flight within hibernacula and may contain open water sources and hibernating insects that can be consumed (Swanson and Evans 1936;Rysgaard 1942). Opportunistic mating is also possible with mixedsex groups typically found in cave hibernacula (Thomas et al. 1979).Bats are also active outside of hibernacula for reasons poorly understood. Early ...

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“…Increasing CO 2 concentrations will have a direct effect on plant production and plant communities and indirectly feed back into a number of soil biotic systems that influence long term ecosystem viability (Hungate et al, 1997a, b, c;Owensby et al, 1993a). The impact of elevated CO 2 on the shortgrass steppe, which is used extensively for grazing and is similar to regions which occupy about 8% of the U.S. and about 11% of global land area (Bailey, 1979) has not been previously addressed. These interactive feedbacks on the soil C and N cycles and their influence on trace gas fluxes have potentially important impacts on the global atmospheric budgets of the gases and the long term sustainability of the grassland.…”

Section: Introductionmentioning

confidence: 99%

Effect of water addition and nitrogen fertilization on the fluxes of CH4, CO2, NOx, and N2O following five years of elevated CO2 in the Colorado Shortgrass Steppe

2003

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Abstract. An open-top-chamber (OTC) CO 2 enrichment (∼720 µmol mol −1 ) study was conducted in the Colorado shortgrass steppe from April 1997 through October 2001. Aboveground plant biomass increased under elevated CO 2 and soil moisture content was typically higher than under ambient CO 2 conditions. Fluxes of CH 4 , CO 2 , NO x and N 2 O, measured weekly year round were not significantly altered by CO 2 enrichment over the 55 month period of observation. During early summer of 2002, following the removal of the open-top-chambers from the CO 2 enrichment sites in October 2001, we conducted a short term study to determine if soil microbial processes were altered in soils that had been exposed to double ambient CO 2 concentrations during the growing season for the past five years. Microplots were established within each experimental site and 10 mm of water or 10 mm of water containing the equivalent of 10 g m −2 of ammonium nitrate-N was applied to the soil surface. Fluxes of CO 2 , CH 4 , NO x and N 2 O fluxes within control (unchambered), ambient CO 2 and elevated CO 2 OTC soils were measured at one to three day intervals for the next month. With water addition alone, CO 2 and NO emission did not differ between ambient and elevated CO 2 soils, while CH 4 uptake rates were higher and N 2 O fluxes lower in elevated CO 2 soils. Adding water and mineral N resulted in increased CO 2 emissions, increased CH 4 uptake and decreased NO emissions in elevated CO 2 soils. The N addition study confirmed previous observations that soil respiration is enhanced under elevated CO 2 and N immobilization is increased, thereby decreasing NO emission.

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Semi-Arid Climates: Their Definition and Distribution

Cited by 66 publications

References 13 publications

Elevated CO₂and warming effects on CH₄uptake in a semiarid grassland below optimum soil moisture

Elevated CO₂and warming effects on CH₄uptake in a semiarid grassland below optimum soil moisture

Environmental correlates and energetics of winter flight by bats in southern Alberta, Canada

Effect of water addition and nitrogen fertilization on the fluxes of CH<sub>4</sub>, CO<sub>2</sub>, NO<sub>x</sub>, and N<sub>2</sub>O following five years of elevated CO<sub>2</sub> in the Colorado Shortgrass Steppe

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Semi-Arid Climates: Their Definition and Distribution

Cited by 66 publications

References 13 publications

Elevated CO2and warming effects on CH4uptake in a semiarid grassland below optimum soil moisture

Elevated CO2and warming effects on CH4uptake in a semiarid grassland below optimum soil moisture

Environmental correlates and energetics of winter flight by bats in southern Alberta, Canada

Effect of water addition and nitrogen fertilization on the fluxes of CH&lt;sub&gt;4&lt;/sub&gt;, CO&lt;sub&gt;2&lt;/sub&gt;, NO&lt;sub&gt;x&lt;/sub&gt;, and N&lt;sub&gt;2&lt;/sub&gt;O following five years of elevated CO&lt;sub&gt;2&lt;/sub&gt; in the Colorado Shortgrass Steppe

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About

Elevated CO₂and warming effects on CH₄uptake in a semiarid grassland below optimum soil moisture

Elevated CO₂and warming effects on CH₄uptake in a semiarid grassland below optimum soil moisture

Effect of water addition and nitrogen fertilization on the fluxes of CH<sub>4</sub>, CO<sub>2</sub>, NO<sub>x</sub>, and N<sub>2</sub>O following five years of elevated CO<sub>2</sub> in the Colorado Shortgrass Steppe