Upscaling Stem to Community-Level Transpiration for Two Sand-Fixing Plants: Salix gordejevii and Caragana microphylla

Abstract

Abstract:The information on transpiration is vital for sustaining fragile ecosystem in arid/semiarid environment, including the Horqin Sandy Land (HSL) located in northeast China. However, such information is scarce in existing literature. The objectives of this study were to: (1) measure sap flow of selected individual stems of two sand-fixing plants, namely Salix gordejevii and Caragana microphylla, in HSL; and (2) upscale the measured stem-level sap flow for estimating the community-level transpiration. The measurements were done from 1 May to 30 September 2015 (i.e., during the growing season). The upscaling function was developed to have one dependent variable, namely sap flow rate, and two independent variables, namely stem cross-sectional area of Salix gordejevii and leaf area of Caragana microphylla. The results indicated that during the growing season, the total actual transpiration of the Salix gordejevii and Caragana microphylla communities was found to be 287 ± 31 and 197 ± 24 mm, respectively, implying that the Salix gordejevii community might consume 1.5 times more water than the Caragana microphylla community. For this same growing season, based on the Penman-Monteith equation, the total actual evapotranspiration for these two communities was estimated to be 323 and 229 mm, respectively. The daily transpiration from the upscaling function was well correlated with the daily evapotranspiration by the Penman-Monteith equation (coefficient of determination R 2 ≥ 0.67), indicating the applicability of this upscaling function, a useful tool for managing and restoring sand-fixing vegetations.

Water–Soil–Vegetation Dynamic Interactions in Changing Climate

“…For an area of interest, the impacts of climate variability and anthropogenic activities tend to affect runoff interactively, while their relative individual impact usually depends on the population. Further, two articles [46,47] examined evaporation from freezing soils and transpiration from sparse-vegetation environments, where the ecosystems are vulnerable and sensitive to water-soil-vegetation interactions. Given that such ecosystems are common across the world, the results presented in these two articles can be insightful for how to protect the global eco-environment.…”

“…The articles cover a wide range of geographic regions across China [39][40][41][42][43][44]46,47,49,50] and the United States of America (USA) [45,48] with contrasting hydro-climate, soil, and vegetation conditions. Thus, the results presented in these articles can have global inferences: the data, analysis/modeling approaches, results, and findings will lay a solid foundation to further our scientific understanding of water-soil-vegetation interactions, ultimately leading to the development of practically effective solutions to sustaining the globe's ecosystem health and productivity.…”

“…The specific topics include steppe vegetation affected by climate change [39,40], interactions of climate, anthropogenic activities, and watershed hydrology [41][42][43], SWAT modeling for quantifying topography-controlled hydrologic processes and sediment yield [44,45], snow cover and frozen soil dynamics in cold regions [46], quantification of plant transpiration in arid/semiarid environment [47], coupled infiltration-runoff modeling for slope stability analysis [48], and assessment of nutrients in aquatic systems [49,50]. In terms of methodologies, these studies involve both field/laboratory experiments and mathematical modeling across different scales.…”

“…The findings from this study can be potentially used for soil-water management, soil salinity control, and integrated crop management. Duan et al [47] measured sap flow of individual stems of two selected plants and then estimated the community-level transpiration using an upscaling function for a site in the Horqin Sandy Land in Northeast China. Their study emphasized the important role of the plant community in stabilizing fixed and semi-fixed sandy dunes.…”

Measurement of actual evapotranspiration in a páramo ecosystem using portable closed chambers: Comparison between giant rosettes, tussock grasses and shrubs

“…This method has been previously applied to páramos (Buytaert, Iñiguez, et al, 2006; Cordova et al, 2015; Leguizamon & Tobón, 2017; Ochoa‐Sanchez et al, 2019), as well as in other high altitude ecosystems (van den Bergh et al, 2013). Then, the main methods proposed in the literature to determine actual ETa (Damveld et al, 2018) are (1) the use of lysimeter (Coners et al, 2016; Ochoa‐Sanchez et al, 2019; van den Bergh et al, 2013); (2) sapflow measurements (Duan et al, 2017; Granier & Loustau, 1994; Zhang et al, 1997); (3) the Eddy covariance method (Carrillo‐Rojas et al, 2019; Gu et al, 2008; Ochoa‐Sanchez et al, 2019); and (4) the use of either closed (McLeod et al, 2004) or ventilated (Denmead et al, 1993; Zhang et al, 2018) chambers encompassing an individual plant or a vegetation patch.…”