scholarly journals Environmental drivers of taxonomic and phylogenetic diversity patterns of plant communities in semi-arid steppe rangelands of North Africa

2021 ◽  
Vol 132 ◽  
pp. 108279
Author(s):  
Amale Macheroum ◽  
Leila Kadik ◽  
Souad Neffar ◽  
Haroun Chenchouni
Keyword(s):  
Plant Communities ◽  
North Africa ◽  
Phylogenetic Diversity ◽  
Environmental Drivers ◽  
Diversity Patterns ◽  
Arid Steppe ◽  
Semi Arid

Effects of defoliation timing on plant nutrient resorption and hay production in a semi-arid steppe

2020 ◽  
Author(s):  
Tongrui Zhang ◽  
Frank Yonghong Li ◽  
Hao Wang ◽  
Lin Wu ◽  
Chunjun Shi ◽  
...  
Keyword(s):  
Nutrient Cycling ◽  
Nutrient Resorption ◽  
Plant Production ◽  
Conservation Strategy ◽  
Plant Nutrient ◽  
Resorption Efficiency ◽  
Nutrient Return ◽  
Peak Biomass ◽  
Arid Steppe ◽  
Semi Arid

Abstract Aims Nutrient resorption is a key plant nutrient conservation strategy, and its response to environmental and management changes is linked to nutrient cycling and production of ecosystems. Defoliation is a major pathway of mowing affecting plant nutrient resorption and production in grasslands, while the effect of defoliation timing has not been unexplored. The aim of this study was to examine the effect of defoliation timing on plant nutrient resorption and production in a steppe ecosystem. Methods We conducted a field experiment in a semi-arid steppe of Inner Mongolia including four treatments: early defoliation, peak defoliation, late defoliation and non-defoliation. We measured plant nitrogen (N) and phosphorus (P) resorption at species and community levels, and quantified plant N and P fluxes in resorption, litter return and hay output. Plant production in the mowing system was assessed by hay production and quality. Important Findings Peak and late defoliation, but not early defoliation, reduced plant community N and P resorption proficiency (RP); and late defoliation reduced N resorption efficiency (RE) but not P resorption efficiency. Peak and late defoliation, but not early defoliation, reduced plant nutrient resorption flux and litter nutrient return flux. Defoliation timing did not alter root nutrient accumulation as nutrient uptake from soil likely compensated the deficit of nutrient resorption. Peak defoliation had the highest hay production and quality, while early defoliation had the lowest. Our results provide new insights into the nutrient cycling in mowing grassland, and imply that the mowing timing can be used as a tool to mediate the balance between conservation and production of steppes, and the early mowing before plant peak biomass period is recommended for conservation of the steppes while keeping sustainable pastoral production.

Seasonal patterns of the abundance of ground-dwelling arthropod guilds and their responses to livestock grazing in a semi-arid steppe

Pedobiologia ◽  
2021 ◽  
Vol 85-86 ◽  
pp. 150711
Author(s):  
Jianwei Cheng ◽  
Frank Yonghong Li ◽  
Xinmin Liu ◽  
Xinyu Wang ◽  
Dong Zhao ◽  
...  
Keyword(s):  
Livestock Grazing ◽  
Seasonal Patterns ◽  
Arid Steppe ◽  
Semi Arid

Controls of surface soil moisture spatial patterns and their temporal stability in a semi-arid steppe

2010 ◽  
Vol 24 (18) ◽  
pp. 2507-2519 ◽  
Author(s):  
Y. Zhao ◽  
S. Peth ◽  
X. Y. Wang ◽  
H. Lin ◽  
R. Horn
Keyword(s):  
Soil Moisture ◽  
Spatial Patterns ◽  
Surface Soil ◽  
Temporal Stability ◽  
Surface Soil Moisture ◽  
Arid Steppe ◽  
Semi Arid

Taxonomic Dependency of Beta Diversity for Bacteria, Archaea and Fungi in a Semi-Arid Lake

2021 ◽  
Author(s):  
Haijun Yuan ◽  
Weizhen Zhang ◽  
Huaqun Yin ◽  
Runyu Zhang ◽  
Jianjun Wang
Keyword(s):  
Water Depth ◽  
Beta Diversity ◽  
Species Turnover ◽  
Environmental Drivers ◽  
Ecological Processes ◽  
Environmental Selection ◽  
Community Variation ◽  
Taxonomic Groups ◽  
Semi Arid ◽  
Total Beta

Abstract Microbial beta diversity has been recently studied along the water depth in aquatic ecosystems, however its turnover and nestedness components remain elusive especially for multiple taxonomic groups. Based on the beta diversity partitioning developed by Baselga and Local Contributions to Beta Diversity (LCBD) partitioning by Legendre, we examined the water-depth variations in beta diversity components of bacteria, archaea and fungi in surface sediments of Hulun Lake, a semi-arid lake in northern China, and further explored the relative importance of environmental drivers underlying their patterns. We found that the relative abundances of Proteobacteria, Chloroflexi, Euryarchaeota and Rozellomycota increased towards deep water, while Acidobacteria, Parvarchaeota and Chytridiomycota decreased. For bacteria and archaea, there were significant (P < 0.05) decreasing water-depth patterns for LCBD and LCBDRepl (i.e., species replacement), while increasing patterns for total beta diversity and turnover, implying that total beta diversity and LCBD were dominated by species turnover or LCBDRepl. Further, bacteria showed a strong correlation with archaea regarding LCBD, total beta diversity and turnover. Such parallel patterns among bacteria and archaea were underpinned by similar ecological processes like environmental selection. Total beta diversity and turnover were largely affected by sediment total nitrogen, while LCBD and LCBDRepl were mainly constrained by water NO2−-N and NO3−-N. For fungal community variation, no significant patterns were observed, which may be due to different drivers like water nitrogen or phosphorus. Taken together, our findings provide compelling evidences for disentangling the underlying mechanisms of community variation in multiple aquatic microbial taxonomic groups.

scholarly journals Global vegetation variability and its response to elevated CO<sub>2</sub>, global warming, and climate variability – a study using the offline SSiB4/TRIFFID model and satellite data

2019 ◽  
Vol 10 (1) ◽  
pp. 9-29 ◽  
Author(s):  
Ye Liu ◽  
Yongkang Xue ◽  
Glen MacDonald ◽  
Peter Cox ◽  
Zhengqiu Zhang
Keyword(s):  
Global Warming ◽  
Climate Variability ◽  
Environmental Drivers ◽  
Arid Areas ◽  
Area Index ◽  
Substantial Impact ◽  
Positive Effects ◽  
Vegetation Fraction ◽  
Before And After ◽  
Semi Arid

Abstract. The climate regime shift during the 1980s had a substantial impact on the terrestrial ecosystems and vegetation at different scales. However, the mechanisms driving vegetation changes, before and after the shift, remain unclear. In this study, we used a biophysical dynamic vegetation model to estimate large-scale trends in terms of carbon fixation, vegetation growth, and expansion during the period 1958–2007, and to attribute these changes to environmental drivers including elevated atmospheric CO2 concentration (hereafter eCO2), global warming, and climate variability (hereafter CV). Simulated leaf area index (LAI) and gross primary production (GPP) were evaluated against observation-based data. Significant spatial correlations are found (correlations > 0.87), along with regionally varying temporal correlations of 0.34–0.80 for LAI and 0.45–0.83 for GPP. More than 40 % of the global land area shows significant positive (increase) or negative (decrease) trends in LAI and GPP during 1958–2007. Regions over the globe show different characteristics in terms of ecosystem trends before and after the 1980s. While 11.7 % and 19.3 % of land have had consistently positive LAI and GPP trends, respectively, since 1958, 17.1 % and 20.1 % of land saw LAI and GPP trends, respectively, reverse during the 1980s. Vegetation fraction cover (FRAC) trends, representing vegetation expansion and/or shrinking, are found at the edges of semi-arid areas and polar areas. Environmental drivers affect the change in ecosystem trend over different regions. Overall, eCO2 consistently contributes to positive LAI and GPP trends in the tropics. Global warming mostly affects LAI, with positive effects in high latitudes and negative effects in subtropical semi-arid areas. CV is found to dominate the variability of FRAC, LAI, and GPP in the semi-humid and semi-arid areas. The eCO2 and global warming effects increased after the 1980s, while the CV effect reversed during the 1980s. In addition, plant competition is shown to have played an important role in determining which driver dominated the regional trends. This paper presents new insight into ecosystem variability and changes in the varying climate since the 1950s.

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