2. Shaping the savannas

2016 ◽  
pp. 16-46
Author(s):  
Peter A. Furley
Keyword(s):  
Climatic Change ◽  
Seasonal Variations ◽  
Soil Profile ◽  
Human Activities ◽  
Continuous Change ◽  
Determining Factors ◽  
Change Climate ◽  
The Impact ◽  
Underlying Soil

Savanna landscapes are in a state of continuous change. Some of the determining factors shaping the view at any given locality are relatively short-lived. Fires, storms, seasonal variations, and some wildlife disturbances or human activities last for days, weeks, or a few months. Other factors influence the landscape over much longer stretches of time, such as the development of the underlying soil profile and more gradual processes of climatic change. ‘Shaping the savannas’ considers the drivers of this continuous change: climate; the role of vegetation; the impact of fire and burning–regrowth cycles; the influence of soils; animals and microbes; and humans, the principal determinants of the savanna landscape.

scholarly journals Fluvial Geomorphology and River Management

Water ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1608
Author(s):  
Salvatore Ivo Giano
Keyword(s):  
Human Activities ◽  
River Restoration ◽  
Fluvial Geomorphology ◽  
Landscape Evolution ◽  
River Management ◽  
Special Issue ◽  
Fluvial Systems ◽  
The Impact

This Special Issue deals with the role of fluvial geomorphology in landscape evolution and the impact of human activities on fluvial systems, which require river restoration and management [...]

Lake level change, climate, and the impact of natural events: the role of seismic and volcanic events in the formation of the Lake Patzcuaro Basin, Michoacan, Mexico

2005 ◽  
Vol 135 (1) ◽  
pp. 35-46 ◽  
Author(s):  
I. Israde-Alcántara ◽  
V.H. Garduño-Monroy ◽  
C.T. Fisher ◽  
H.P. Pollard ◽  
M.A. Rodríguez-Pascua
Keyword(s):  
Lake Level ◽  
Lake Level Change ◽  
Level Change ◽  
Volcanic Events ◽  
Lake Patzcuaro Basin ◽  
Change Climate ◽  
The Impact

scholarly journals Spatial and temporal variations of CO<sub>2</sub> mole fractions observed at Beijing, Xianghe and Xinglong in North China

2021 ◽  
Author(s):  
Yang Yang ◽  
Minqiang Zhou ◽  
Ting Wang ◽  
Bo Yao ◽  
Pengfei Han ◽  
...  
Keyword(s):  
Seasonal Variations ◽  
Human Activities ◽  
North China ◽  
Terrestrial Ecosystem ◽  
Temporal Variations ◽  
Spatial And Temporal Variations ◽  
Boundary Layer Height ◽  
The Mean ◽  
The Impact ◽  
First Time

Abstract. Atmospheric CO2 mole fractions are observed at Beijing (BJ), Xianghe (XH), and Xinglong (XL) in North China using the Picarro G2301 Cavity Ring-Down Spectroscopy instruments. The measurement system is described comprehensively for the first time. The geo-distances among these three sites are within 200 km, but they have very different surrounding environments: BJ is inside the megacity; XH is in the suburban area; XL is in the countryside on a mountain. The mean and standard deviation of CO2 mole fractions at BJ, XH, and XL between October 2018 and September 2019 are 448.4 ± 12.8 ppm, 436.0 ± 9.2 ppm and 420.6 ± 8.2 ppm, respectively. The seasonal variations of CO2 at these three sites are similar, with a maximum in winter and a minimum in summer, which is dominated by the terrestrial ecosystem. However, the seasonal variations of CO2 at BJ and XH are more affected by human activities as compared to XL. By using CO2 at XL as the background, CO2 enhancements are observed simultaneously at BJ and XH. The diurnal variations of CO2 are driven by the boundary layer height, photosynthesis and human activities at BJ, XH and XL. Moreover, we address the impact of the wind on the CO2 mole fractions at BJ and XL. This study provides an insight into the spatial and temporal variations of CO2 mole fractions in North China.

scholarly journals Arsenate Retention by Epipsammic Biofilms Developed on Streambed Sediments: Influence of Phosphate

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
D. M. Prieto ◽  
R. Devesa-Rey ◽  
D. A. Rubinos ◽  
F. Díaz-Fierros ◽  
M. T. Barral
Keyword(s):  
Experimental Data ◽  
Environmental Quality ◽  
Human Activities ◽  
Sediment Samples ◽  
Average Percentage ◽  
Geological Conditions ◽  
Streambed Sediments ◽  
The Impact

Natural geological conditions together with the impact of human activities could produce environmental problems due to high As concentrations. The aim of this study was to assess the role of epipsammic biofilm-sediment systems onto As (V) sorption and to evaluate the effect of the presence of equimolar P concentrations on As retention. A natural biofilm was grown on sediment samples in the laboratory, using river water as nutrient supplier. Sorption experiments with initial As concentrations 0, 5, 25, 50, 100, 250, and 500 μg L−1were performed. The average percentage of As sorbed was78.9±3.5and96.9±6.6% for the sediment and biofilm-sediment systems, respectively. Phosphate decreased by 25% the As sorption capactity in the sediment devoid of biofilm, whereas no significant effect was observed in the systems with biofilm. Freundlich, Sips, and Toth models were the best to describe experimental data. The maximum As sorption capacity of the sediment and biofilm-sediment systems was, respectively, 6.6 and 6.8 μg g−1and 4.5 and 7.8 μg g−1in the presence of P. In conclusion, epipsammic biofilms play an important role in the environmental quality of river systems, increasing As retention by the system, especially in environments where both As and P occur simultaneously.

Relinquishment for Adoption of Babies with Down's Syndrome: Parents' Response to the Diagnosis and the Role of Health Professionals

2001 ◽  
Vol 25 (2) ◽  
pp. 49-55 ◽  
Author(s):  
Annick-Camille Dumaret ◽  
Dominique Rosset
Keyword(s):  
Health Professionals ◽  
Down's Syndrome ◽  
Down’S Syndrome ◽  
Determining Factors ◽  
Research Findings ◽  
The Impact

Annick-Camille Dumaret and Dominique Rosset present a synthesis of research findings based on a study conducted in France between 1990 and 1996. The project aimed to establish a clearer understanding of why infants with Down's Syndrome were given up for adoption, to evaluate the extent of the phenomenon and its evolution over the long term. It also analysed the impact of the diagnosis on the parents' decision about whether to keep the baby or not and highlighted the determining factors in babies being given up for adoption.

scholarly journals Spatial and temporal variations of CO<sub>2</sub> mole fractions observed at Beijing, Xianghe, and Xinglong in North China

2021 ◽  
Vol 21 (15) ◽  
pp. 11741-11757
Author(s):  
Yang Yang ◽  
Minqiang Zhou ◽  
Ting Wang ◽  
Bo Yao ◽  
Pengfei Han ◽  
...  
Keyword(s):  
Seasonal Variations ◽  
Human Activities ◽  
North China ◽  
Terrestrial Ecosystem ◽  
Temporal Variations ◽  
Spatial And Temporal Variations ◽  
Boundary Layer Height ◽  
The Usa ◽  
Geographical Distances ◽  
The Impact

Abstract. Atmospheric CO2 mole fractions are observed at Beijing (BJ), Xianghe (XH), and Xinglong (XL) in North China using Picarro G2301 cavity ring-down spectroscopy instruments. The measurement system is described comprehensively for the first time. The geographical distances among these three sites are within 200 km, but they have very different surrounding environments: BJ is inside the megacity; XH is in the suburban area; XL is in the countryside on a mountain. The mean and standard deviation of CO2 mole fractions at BJ, XH, and XL between October 2018 and September 2019 are 448.4±12.8, 436.0±9.2, and 420.6±8.2 ppm, respectively. The seasonal variations of CO2 at these three sites are similar, with a maximum in winter and a minimum in summer, which is dominated by the terrestrial ecosystem. However, the seasonal variations of CO2 at BJ and XH are more affected by human activities as compared to XL. Using CO2 at XL as the background, CO2 enhancements are observed simultaneously at BJ and XH. The diurnal variations of CO2 are driven by the boundary layer height, photosynthesis, and human activities at BJ, XH, and XL. We also compare the CO2 measurements at BJ, XH, and XL with five urban sites in the USA, and it is found that the CO2 mean concentration at BJ is the largest. Moreover, we address the impact of the wind on the CO2 mole fractions at BJ and XL. This study provides an insight into the spatial and temporal variations of CO2 mole fractions in North China.

The role of drought in the impact of climatic change on the microbiota of peatland streams

1994 ◽  
Vol 32 (1) ◽  
pp. 223-230 ◽  
Author(s):  
C. FREEMAN ◽  
R. GRESSWELL ◽  
H. GUASCH ◽  
J. HUDSON ◽  
M.A. LOCK ◽  
...  
Keyword(s):  
Climatic Change ◽  
The Impact

Temperature and extinction in the sea: a physiologist's view

Paleobiology ◽  
1993 ◽  
Vol 19 (4) ◽  
pp. 499-518 ◽  
Author(s):  
Andrew Clarke
Keyword(s):  
Climatic Change ◽  
Temperature Change ◽  
Evolutionary History ◽  
Marine Invertebrates ◽  
Seawater Temperature ◽  
Ecological Factors ◽  
Proximate Cause ◽  
History Of ◽  
The Impact

Climatic change has long been regarded as an important factor in evolutionary history. In particular, periods of enhanced extinction in marine taxa (especially those from warmer waters) have frequently been linked to decreases in seawater temperature. Studies of the physiology of marine invertebrates and fish alive today have revealed well-developed abilities to cope with temperature change, and there would thus appear to be a dichotomy between the rates of temperature change associated with extinction in geological history and the very much faster rates (by several orders of magnitude) with which many marine organisms can cope today. Nevertheless, evidence from ecology and biogeography indicates that temperature, or some temperature-associated factor, does play a significant role in determining the limits to performance, and hence distribution. The resolution of the dichotomy between the evidence from paleontology and physiology may come through a consideration of the role of the previous evolutionary history of the fauna, the influence of sudden temperature events, or the impact of climatic change on individual competitive ability, community structure, and ecosystem functioning. Studies of the energetics of marine invertebrates in relation to temperature and the evolutionary history of polar faunas indicate that we should beware of anthropocentric judgements in attempting to understand the role of climatic change in evolutionary history, and be critical in distinguishing the role of temperature per se from temperature-associated ecological factors. Present evidence suggests that climatic change in the sea, at least at the rates currently believed to be typical, is unlikely to cause extinction by direct physiological impact. It is more likely that extinction is caused by ecological factors; temperature change is thus only one of several factors that may promote those ecological changes that are currently the best candidates for the proximate cause of extinction in the sea.

Intergroup Threat and Outgroup Attitudes

2013 ◽  
Vol 44 (5) ◽  
pp. 311-319 ◽  
Author(s):  
Marco Brambilla ◽  
David A. Butz
Keyword(s):  
Gay Men ◽  
Social Group ◽  
Welfare Recipients ◽  
Intergroup Attitudes ◽  
Social Policies ◽  
Intergroup Threat ◽  
Economic Threat ◽  
The Impact ◽  
General Climate

Two studies examined the impact of macrolevel symbolic threat on intergroup attitudes. In Study 1 (N = 71), participants exposed to a macrosymbolic threat (vs. nonsymbolic threat and neutral topic) reported less support toward social policies concerning gay men, an outgroup whose stereotypes implies a threat to values, but not toward welfare recipients, a social group whose stereotypes do not imply a threat to values. Study 2 (N = 78) showed that, whereas macrolevel symbolic threat led to less favorable attitudes toward gay men, macroeconomic threat led to less favorable attitudes toward Asians, an outgroup whose stereotypes imply an economic threat. These findings are discussed in terms of their implications for understanding the role of a general climate of threat in shaping intergroup attitudes.

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