Restoration of a Shrub‐Encroached Semiarid Grassland: Implications for Structural, Hydrologic, and Sediment Connectivity

Ecohydrology ◽  
2021 ◽  
Author(s):  
Justin C. Johnson ◽  
C. Jason Williams ◽  
D. Phillip Guertin ◽  
Steven R. Archer ◽  
Philip Heilman ◽  
...  
Keyword(s):  
Semiarid Grassland ◽  
Sediment Connectivity

Development and application of a sediment connectivity index to small fluvial catchments: a case study in Arenoso stream, Córdoba, Argentina

2021 ◽  
Vol 80 (8) ◽  
Author(s):  
María Jimena Andreazzini ◽  
Susana Beatriz Degiovanni ◽  
María Eugenia Benito ◽  
Karina Vanesa Echevarria
Keyword(s):  
Connectivity Index ◽  
Sediment Connectivity

Spatial Patterns of Roots in a Semiarid Grassland: Abundance of Canopy Openings and Regeneration Gaps

1994 ◽  
Vol 82 (3) ◽  
pp. 485 ◽  
Author(s):  
Paul B. Hook ◽  
William K. Lauenroth ◽  
Ingrid C. Burke
Keyword(s):  
Spatial Patterns ◽  
Semiarid Grassland

Heavy rainfall in peak growing season had larger effects on soil nitrogen flux and pool than in the late season in a semiarid grassland

2022 ◽  
Vol 326 ◽  
pp. 107785
Author(s):  
Linfeng Li ◽  
Yanbin Hao ◽  
Zhenzhen Zheng ◽  
Weijin Wang ◽  
Joel A. Biederman ◽  
...  
Keyword(s):  
Soil Nitrogen ◽  
Heavy Rainfall ◽  
Growing Season ◽  
Nitrogen Flux ◽  
Semiarid Grassland ◽  
Late Season

Structural, Hydrologic, and Sediment Connectivity in a Shrub-Encroached and Restored Semiarid Grassland

2021 ◽  
Author(s):  
Justin Johnson ◽  
Jason Williams ◽  
Phillip Guertin ◽  
Steven Archer ◽  
Philip Heilman ◽  
...  
Keyword(s):  
Sediment Yield ◽  
Soil Loss ◽  
Rainfall Intensity ◽  
Overland Flow ◽  
Spatial Scales ◽  
Structural Connectivity ◽  
Post Treatment ◽  
Semiarid Grassland ◽  
Concentrated Flow ◽  
Shrub Canopy

<p>Shrub encroachment of semiarid grasslands is influenced by connected runoff and erosion patterns that preferentially accumulate resources under vegetated patches (canopy microsites) and deplete interspaces. Soil loss from dryland hillslopes results when areas of bare ground become structurally and functionally connected through overland flow. Although these patterns have been well-described, uncertainty remains regarding how these feedbacks respond to restoration practices. This study compared the structure and hydrologic function of a shrub-encroached semiarid grassland treated five years prior with the herbicide, tebuthiuron, to that of an adjacent untreated grassland. Through a series of hydrologic experiments conducted at increasing spatial scales, vegetation and soil structural patterns were related to runoff and erosion responses. At a fine scale (0.5 m<sup>2</sup>), rainfall simulations (120 mm·h<sup>-1</sup> rainfall intensity; 45 min) showed herbicided shrub canopy microsites had greater infiltration capacities (105 and 71 mm·h<sup>-1</sup> terminal infiltration rates) and were less susceptible to splash-sheet erosion (3 and 26 g sediment yield) than untreated shrub canopy microsites, while interspaces were statistically comparable between study sites. Concentrated flow simulations at a coarse scale (~9 m<sup>2</sup>) revealed that gaps between the bases of vegetation (i.e. basal gaps) > 2 m<sup></sup>were positively related to both concentrated flow runoff (r = 0.72, p = 0.008) and sediment yield (r = 0.70, p = 0.012). Modeled hillslope-scale (50 m<sup>2</sup>) runoff and erosion (120 mm·h<sup>-1</sup> rainfall intensity; 45 min) indicated less soil loss in the tebuthiuron-treated site (1.78 Mg·ha<sup>-1</sup> tebuthiuron; 3.19 Mg·ha<sup>-1</sup> untreated), even though runoff was similar between sites. Our results suggest interspaces in shrub-encroached grasslands continue to be runoff sources following herbicide-induced shrub mortality and may be indicators of runoff responses at larger spatial scales. In contrast, sediment sources are limited post-treatment due to lesser sediment detachment from sheet-splash and concentrated flow processes. Reduced sediment supplies provide evidence that connectivity feedbacks that sustain a shrub-dominant ecological state may have been dampened post-treatment. Our study also highlights the utility of simple measures of structural connectivity, such as basal gaps, as an indicator of hillslope susceptibility to increased runoff and erosion.</p>

The Distributive Characteristics of Soil Microorganisms at Dry Lake Wetland on Semiarid Grassland

2011 ◽  
Vol 71-78 ◽  
pp. 2882-2886 ◽  
Author(s):  
Yu Qin Shao ◽  
Zi Long Zhao ◽  
Miao Miao Hou ◽  
Hui Min ◽  
Zhong Ling Liu ◽  
...  
Keyword(s):  
Soil Microorganisms ◽  
The Other ◽  
Microbial Biomass C ◽  
Semiarid Grassland ◽  
Typical Steppe ◽  
Exploitation And Utilization ◽  
Significant Difference ◽  
Microbial Resources ◽  
Dry Lake ◽  
Lake Center

This research investigated the distributive characteristics of soil microorganisms at dry lake wetland on semiarid grassland. Four plots, typical steppe (DT), lake side (HB), lake bed (HD), and lake center (HX), were selected from Huitengxile located in semiarid grassland to conducted this investigation. The results showed that the number of aerobic bacteria at DT is 1.07 times that at HB, 1.14 times that at HX, and 1.45 times that at HD. The number of fungi at DT is 3.81 times that at HD, 10.65 times that at HB, and 25.75 times that at HX. There is significant difference between HX, HB and the other two plots (p<0.05). Also, there is significant difference between HD and DT. The number of Spore-forming bacteria at DT is 1.65 times that at HD, 2.15 times that at HB, and 6.35 times that at HX. There is significant difference between HD, HB and the other two plots, as well. The number of actinomycetes at HB is highest which is 2.12 times that at HD, 2.27 times that at DT, and 3.43 times that at HX. Moreover, there is a distinct feature of transverse distribution for soil microorganisms communities at dry lake wetland on semiarid grassland. Excluding actinomycetes, the number of soil microorganisms at dry lake wetland were both lower than that at typical steppe. There is a significant correlation between the total amount of soil microorganisms and microbial biomass C at dry lake wetland. These results can be used as the theoretical foundation for the restoration of degraded lake wetland, and the exploitation and utilization of wetland microbial resources.

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