Grassland Vegetation Changes and Nocturnal Global Warming

Alward, Richard D.; Detling, James K.; Milchunas, Daniel G.

doi:10.1126/science.283.5399.229

Cited by 310 publications

(229 citation statements)

References 15 publications

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“…Given the spatial variation in the magnitude and direction of change for the parameters tested (Tables III-VI), and highlighted by the geographical anomalies of neighbouring sites (Figure 2), we believe that no one site evaluated in this study is 'typical' of the region. The alarming trend in minimum temperature of 0.12°C/year reported by Alward et al (1999) for CPER since 1970 was four times higher than the average of the other ten stations used in this study over the same period (0.03°C/year) and 12 times higher than the long-term (80+ years) average rate (0.01°C/year). The site was also atypical in trends in summer temperatures and growing-season days.…”

Section: No One Site (In This Study) Is 'Typical' Of the Regionmentioning

confidence: 83%

“…That is, there was also a strong disconnect seasonally, with very few sites showing consistent trends for all seasons; the summer season was the least consistent in minimum and maximum temperatures across the region. This could be unsettling for the agriculture and livestock industry, where decreasing growing season, and minimum and maximum temperatures, at some sites may reduce productivity, while increasing minimum temperatures at other sites may facilitate less desirable invasive plant species (Alward et al, 1999). Unfortunately, temperature trends in the summer growing season were not unidirectional (e.g.…”

Section: Inconsistencies In the Responses Of Multiple Temperature Parmentioning

confidence: 99%

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Problems in evaluating regional and local trends in temperature: an example from eastern Colorado, USA

Pielke

Stohlgren

Schell

et al. 2002

Intl Journal of Climatology

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We evaluated long-term trends in average maximum and minimum temperatures, threshold temperatures, and growing season in eastern Colorado, USA, to explore the potential shortcomings of many climate-change studies that either: (1) generalize regional patterns from single stations, single seasons, or a few parameters over short duration from averaging dissimilar stations; or (2) generalize an average regional pattern from coarse-scale general circulation models. Based on 11 weather stations, some trends were weakly regionally consistent with previous studies of night-time temperature warming. Long-term (80 + years) mean minimum temperatures increased significantly (P < 0.2) in about half the stations in winter, spring, and autumn and six stations had significant decreases in the number of days per year with temperatures ≤ − 17.8°C (≤0°F). However, spatial and temporal variation in the direction of change was enormous for all the other weather parameters tested, and, in the majority of tests, few stations showed significant trends (even at P < 0.2). In summer, four stations had significant increases and three stations had significant decreases in minimum temperatures, producing a strongly mixed regional signal. Trends in maximum temperature varied seasonally and geographically, as did trends in threshold temperature days ≥32.2°C (≥90°F) or days ≥37.8°C (≥100°F). There was evidence of a subregional cooling in autumn's maximum temperatures, with five stations showing significant decreasing trends. There were many geographic anomalies where neighbouring weather stations differed greatly in the magnitude of change or where they had significant and opposite trends. We conclude that sub-regional spatial and seasonal variation cannot be ignored when evaluating the direction and magnitude of climate change. It is unlikely that one or a few weather stations are representative of regional climate trends, and equally unlikely that regionally projected climate change from coarse-scale general circulation models will accurately portray trends at sub-regional scales. However, the assessment of a group of stations for consistent more qualitative trends (such as the number of days less than −17.8°C, such as we found) provides a reasonably robust procedure to evaluate climate trends and variability.

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Section: No One Site (In This Study) Is 'Typical' Of the Regionmentioning

confidence: 83%

Section: Inconsistencies In the Responses Of Multiple Temperature Parmentioning

confidence: 99%

Problems in evaluating regional and local trends in temperature: an example from eastern Colorado, USA

Pielke

Stohlgren

Schell

et al. 2002

Intl Journal of Climatology

View full text Add to dashboard Cite

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“…Temperature is another factor. Increasing spring minimum temperatures correlates with decreased C 4 productivity and benefits C 3 species since C 3 plants are growing most rapidly during spring (Alward et al, 1999). Flourishing cool season species could effectively reduce the amount of resources available to warm season species that begin their growth peaks later in the year.…”

Section: Introductionmentioning

confidence: 99%

Response of Nebraska Sand Hills Natural Vegetation to Drought, Fire, Grazing, and Plant Functional Type Shifts as Simulated by the Century Model

et al. 2004

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Abstract. The Nebraska Sand Hills exist in a semi-arid climatic environment and the land surface is grassland growing on sandy soils. These soils have been periodically active throughout the Holocene, but are currently stabilized by the vegetation. However, a shift in climate could cause grassland death and eventual sand dune remobilization. Our studies used the CENTURY nutrient cycling and ecosystem model to investigate the impacts of drought, plant functional type, fire, grazing, and erosion on Nebraska Sand Hills vegetation and dune stability. Fire and grazing alone had little impact on the vegetation, but when combined with mild drought, biomass decreased. Overall biomass increased if one plant functional type was allowed to dominate the ecosystem. Addition of as little as 1 mm of erosion per year under current climate conditions decreases vegetation as much as a drought 20 percent drier than the worst of the 1930s drought years in Nebraska.

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“…This allows making investigations on one or a few, mostly dominant species as representatives of functional types. Different plant functional types, according to their life form, phenology, vegetative growth, rooting pattern or photosynthesis type, often respond differently to natural or experimentally simulated climatic stresses (Mamolos et al 2001, Fay et al 2002, Xia & Wan 2013, Wertin et al 2015, which may result in changes in the dominance structure and composition of the community (Alward et al 1999, Zavaleta et al 2003.…”

Section: Introductionmentioning

confidence: 99%

Plant ecophysiological responses to drought, nocturnal warming and variable climate in the Pannonian sand forest-steppe: results of a six-year climate manipulation experiment

2017

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The impacts of year-round nocturnal warming or late spring rain exclusion on three plant functional types were studied in a plot-scale climate simulation experiment in a semiarid sand forest-steppe of Central Hungary. Ecophysiological traits were followed through six years for the C3 bunch grass Festuca vaginata, the spreading C4 grass Cynodon dactylon and shrubsized root suckers of Populus alba. In general, experimental treatments had slighter effects than weather fluctuations yielding extremities did. Populus alba responded to nocturnal warming with developing slenderer leaves. Rain exclusion reduced leaf physiological activity or growth, but only during or just after the treatment, and in certain years. When assessing treatment and background climatic variation effects together, in spring, leaf area growth was consistently stimulated by increasing temperature, but decreased with longer rainless periods for P. alba and F. vaginata. Physiological responses in spring indicated low temperature limitation for C. dactylon, and both low and high temperature control for P. alba. Longer summer droughts reduced leaf gas exchange, particularly for F. vaginata with substantial drop in photochemical activity and chlorophyll content. These results suggest that shallow rooted C3 bunch grasses can be the most susceptible to climatic variation, thus their abundance is expected to decline in the Pannonian forest-steppe. In contrast, plants having deeper roots and clonal integration will probably be less affected by the projected warming and drying climate.C4 photosynthesis or southern geographical distribution may also be beneficial, thus, the abundance of such species is expected to diminish less or even increase.

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Grassland Vegetation Changes and Nocturnal Global Warming

Cited by 310 publications

References 15 publications

Problems in evaluating regional and local trends in temperature: an example from eastern Colorado, USA

Problems in evaluating regional and local trends in temperature: an example from eastern Colorado, USA

Response of Nebraska Sand Hills Natural Vegetation to Drought, Fire, Grazing, and Plant Functional Type Shifts as Simulated by the Century Model

Plant ecophysiological responses to drought, nocturnal warming and variable climate in the Pannonian sand forest-steppe: results of a six-year climate manipulation experiment

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