Physiological Ecology of Water Balance in Terrestrial Plants

Ecology ◽  
2019 ◽  
Author(s):  
Paul Barnes
Keyword(s):  
Water Balance ◽  
Water Relations ◽  
Water Availability ◽  
Vascular Tissue ◽  
Water Cycle ◽  
Physiological Ecology ◽  
Photosynthetic Electron Transport ◽  
Terrestrial Ecosystems ◽  
Hydrological Processes ◽  
Terrestrial Plants

Water is one of the most important environmental factors limiting the growth and production of terrestrial (land) plants. Although water is essential for a number of metabolic, physiological, and growth processes in plants (e.g., turgor maintenance and cell elongation, transport of nutrients and carbohydrates, energy dissipation, and photosynthetic electron transport), most plants consume and store very little water. The vast majority of water that is absorbed by a plant’s root system moves through its vascular tissue (xylem) and is lost to the atmosphere as water vapor in the process of transpiration. It is the net difference between this uptake and loss that determines the overall water balance of a plant. Plant species vary considerably in their abilities to capture soil water, how efficiently they utilize water, and their tolerances to desiccation, and this variation has a number of ecological consequences at scales from individual plants to ecosystems, landscapes, and the globe. Historically, plant physiological ecologists studied the water relations of plant cells, tissues, and organs to better understand the molecular, physiological, anatomical, and morphological mechanisms by which plants have adapted to survive drought and cope with limited water availability. For obvious reasons, these studies were concentrated on plants in extreme moisture-limited ecosystems such as deserts, but water relations research was also conducted in other systems that experience intermittent and seasonal drought. Over time, physiological ecologists began to study the water relationships between plants and soil, examined how plants interacted with one another for this resource, and explored how temporal and spatial variation in soil moisture availability influences species distributions and community organization. The study of ecohydrology is a relatively recent interdisciplinary discipline that seeks to study how hydrological processes influence biological communities and also how these systems, in turn, influence the water cycle. Plant physiological ecologists play an important role in ecohydrology research by studying how water influences ecosystem function and quantifying the role of vegetation in influencing hydrological processes. Finally, plant physiological ecologists are increasingly interested in how changes in water availability driven by climate change affects plants and terrestrial ecosystems, how global change factors (e.g., atmospheric CO2) influence plant water relations, and what role vegetation itself plays in influencing the atmosphere and climate. Below are selected sources that highlight the full breadth of the study of the physiological ecology of water balance in plants. An emphasis is placed on terrestrial plants in non-hydric (i.e., non-flooded) environments and sources include a number of classical as well as contemporary publications.

scholarly journals Animal water balance drives top-down effects in a riparian forest—implications for terrestrial trophic cascades

2016 ◽  
Vol 283 (1836) ◽  
pp. 20160881 ◽  
Author(s):  
Kevin E. McCluney ◽  
John L. Sabo
Keyword(s):  
Water Balance ◽  
Water Availability ◽  
Species Interactions ◽  
Riparian Forest ◽  
Trophic Cascades ◽  
Free Water ◽  
Terrestrial Ecosystems ◽  
Leaf Damage ◽  
Top Down ◽  
Spider Abundance

Despite the clear importance of water balance to the evolution of terrestrial life, much remains unknown about the effects of animal water balance on food webs. Based on recent research suggesting animal water imbalance can increase trophic interaction strengths in cages, we hypothesized that water availability could drive top-down effects in open environments, influencing the occurrence of trophic cascades. We manipulated large spider abundance and water availability in 20 × 20 m open-air plots in a streamside forest in Arizona, USA, and measured changes in cricket and small spider abundance and leaf damage. As expected, large spiders reduced both cricket abundance and herbivory under ambient, dry conditions, but not where free water was added. When water was added (free or within moist leaves), cricket abundance was unaffected by large spiders, but spiders still altered herbivory, suggesting behavioural effects. Moreover, we found threshold-type increases in herbivory at moderately low soil moisture (between 5.5% and 7% by volume), suggesting the possibility that water balance may commonly influence top-down effects. Overall, our results point towards animal water balance as an important driver of direct and indirect species interactions and food web dynamics in terrestrial ecosystems.

scholarly journals Partitioning the forest water balance within a boreal catchment using sapflux, eddy covariance and process-based model

2019 ◽  
Author(s):  
Natalia Kozii ◽  
Kersti Haahti ◽  
Pantana Tor-ngern ◽  
Jinshu Chi ◽  
Eliza Maher Hasselquist ◽  
...  
Keyword(s):  
Water Balance ◽  
Eddy Covariance ◽  
Water Loss ◽  
Stand Structure ◽  
Hydrological Cycle ◽  
Water Cycle ◽  
Terrestrial Ecosystems ◽  
Growing Season ◽  
Canopy Interception ◽  
Cascading Effects

Abstract. In the hydrological cycle, water is lost from terrestrial ecosystems either laterally through stream runoff or vertically as evapotranspiration (ET) back to the atmosphere. Although it is well known that ET losses represents an important water loss pathway at local to global scales, the magnitude and relative importance of ET and its individual flux components varies considerable among different ecosystems. In this study, we combined empirical sapflux and eddy covariance measurements with estimates from a process-based model to partition the water balance in a boreal forested catchment. This study was conducted within the Krycklan Catchment, which has state-of-the-art infrastructure for hydrological measurements, thereby providing us the unique opportunity to compare the absolute and relative magnitude of ET and its flux components to other water loss pathways (i.e., stream runoff). During the growing season, ET was the major water loss pathway, representing ca. 85 % of the incoming precipitation and being roughly 7 times greater than stream runoff. Both the empirical results and model estimates suggested that tree transpiration (T) and canopy interception (IL) represented 45 % and 35 % of total ET loss; respectively, and thus together were responsible for 70 % of the water loss during the growing season. Understory evapotranspiration (ETu) was less important than T and IL during most of the study period, except for late autumn when ETu was the largest ET flux component. Overall, our study highlights the importance of trees in regulating the water cycle of boreal catchments, implying that forest management impacts on stand structure as well as climate change effects on tree growth are likely to have large cascading effects on the way water moves through these forested landscapes.

scholarly journals Biomass Burning and Water Balance Dynamics in the Lake Chad Basin in Africa

Earth ◽  
2021 ◽  
Vol 2 (2) ◽  
pp. 340-356
Author(s):  
Forrest W. Black ◽  
Jejung Lee ◽  
Charles M. Ichoku ◽  
Luke Ellison ◽  
Charles K. Gatebe ◽  
...  
Keyword(s):  
Water Balance ◽  
Biomass Burning ◽  
Water Cycle ◽  
Potential Evapotranspiration ◽  
Southern Oscillation ◽  
Wet Season ◽  
Lake Chad ◽  
Chad Basin ◽  
Lake Chad Basin ◽  
Logone Catchment

The present study investigated the effect of biomass burning on the water cycle using a case study of the Chari–Logone Catchment of the Lake Chad Basin (LCB). The Chari–Logone catchment was selected because it supplies over 90% of the water input to the lake, which is the largest basin in central Africa. Two water balance simulations, one considering burning and one without, were compared from the years 2003 to 2011. For a more comprehensive assessment of the effects of burning, albedo change, which has been shown to have a significant impact on a number of environmental factors, was used as a model input for calculating potential evapotranspiration (ET). Analysis of the burning scenario showed that burning grassland, which comprises almost 75% of the total Chari–Logone land cover, causes increased ET and runoff during the dry season (November–March). Recent studies have demonstrated that there is an increasing trend in the LCB of converting shrubland, grassland, and wetlands to cropland. This change from grassland to cropland has the potential to decrease the amount of water available to water bodies during the winter. All vegetative classes in a burning scenario showed a decrease in ET during the wet season. Although a decrease in annual precipitation in global circulation processes such as the El Niño Southern Oscillation would cause droughts and induce wildfires in the Sahel, the present study shows that a decrease in ET by the human-induced burning would cause a severe decrease in precipitation as well.

scholarly journals Estimating surface runoff and groundwater recharge in an urban catchment using a water balance approach

2021 ◽  
Vol 29 (7) ◽  
pp. 2411-2428
Author(s):  
Robin K. Weatherl ◽  
Maria J. Henao Salgado ◽  
Maximilian Ramgraber ◽  
Christian Moeck ◽  
Mario Schirmer
Keyword(s):  
Soil Moisture ◽  
Water Balance ◽  
Groundwater Recharge ◽  
Surface Runoff ◽  
Urban Areas ◽  
Water Cycle ◽  
Land Use Changes ◽  
Curve Number ◽  
Hydrograph Separation ◽  
Balance Approach

AbstractLand-use changes often have significant impact on the water cycle, including changing groundwater/surface-water interactions, modifying groundwater recharge zones, and increasing risk of contamination. Surface runoff in particular is significantly impacted by land cover. As surface runoff can act as a carrier for contaminants found at the surface, it is important to characterize runoff dynamics in anthropogenic environments. In this study, the relationship between surface runoff and groundwater recharge in urban areas is explored using a top-down water balance approach. Two empirical models were used to estimate runoff: (1) an updated, advanced method based on curve number, followed by (2) bivariate hydrograph separation. Modifications were added to each method in an attempt to better capture continuous soil-moisture processes and explicitly account for runoff from impervious surfaces. Differences between the resulting runoff estimates shed light on the complexity of the rainfall–runoff relationship, and highlight the importance of understanding soil-moisture dynamics and their control on hydro(geo)logical responses. These results were then used as input in a water balance to calculate groundwater recharge. Two approaches were used to assess the accuracy of these groundwater balance estimates: (1) comparison to calculations of groundwater recharge using the calibrated conceptual HBV Light model, and (2) comparison to groundwater recharge estimates from physically similar catchments in Switzerland that are found in the literature. In all cases, recharge is estimated at approximately 40–45% of annual precipitation. These conditions were found to closely echo those results from Swiss catchments of similar characteristics.

scholarly journals Afforestation of Degraded Croplands as a Water-Saving Option in Irrigated Region of the Aral Sea Basin

Water ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1433
Author(s):  
Navneet Kumar ◽  
Asia Khamzina ◽  
Patrick Knöfel ◽  
John P. A. Lamers ◽  
Bernhard Tischbein
Keyword(s):  
Land Use ◽  
Water Balance ◽  
Water Supply ◽  
Water Availability ◽  
Irrigation Water ◽  
Water Saving ◽  
Aral Sea ◽  
Water Balance Components ◽  
Study Region ◽  
Trade Offs

Climate change is likely to decrease surface water availability in Central Asia, thereby necessitating land use adaptations in irrigated regions. The introduction of trees to marginally productive croplands with shallow groundwater was suggested for irrigation water-saving and improving the land’s productivity. Considering the possible trade-offs with water availability in large-scale afforestation, our study predicted the impacts on water balance components in the lower reaches of the Amudarya River to facilitate afforestation planning using the Soil and Water Assessment Tool (SWAT). The land-use scenarios used for modeling analysis considered the afforestation of 62% and 100% of marginally productive croplands under average and low irrigation water supply identified from historical land-use maps. The results indicate a dramatic decrease in the examined water balance components in all afforestation scenarios based largely on the reduced irrigation demand of trees compared to the main crops. Specifically, replacing current crops (mostly cotton) with trees on all marginal land (approximately 663 km2) in the study region with an average water availability would save 1037 mln m3 of gross irrigation input within the study region and lower the annual drainage discharge by 504 mln m3. These effects have a considerable potential to support irrigation water management and enhance drainage functions in adapting to future water supply limitations.

scholarly journals Risk Assessment of Future Climate and Land Use/Land Cover Change Impacts on Water Resources

Hydrology ◽  
2021 ◽  
Vol 8 (1) ◽  
pp. 38
Author(s):  
Nick Martin
Keyword(s):  
Risk Assessment ◽  
Land Use ◽  
Water Resources ◽  
Land Cover ◽  
Water Balance ◽  
Water Availability ◽  
Reference Conditions ◽  
Weather Generator ◽  
Future Climate ◽  
Lulc Change

Climate and land use and land cover (LULC) changes will impact watershed-scale water resources. These systemic alterations will have interacting influences on water availability. A probabilistic risk assessment (PRA) framework for water resource impact analysis from future systemic change is described and implemented to examine combined climate and LULC change impacts from 2011–2100 for a study site in west-central Texas. Internally, the PRA framework provides probabilistic simulation of reference and future conditions using weather generator and water balance models in series—one weather generator and water balance model for reference and one of each for future conditions. To quantify future conditions uncertainty, framework results are the magnitude of change in water availability, from the comparison of simulated reference and future conditions, and likelihoods for each change. Inherent advantages of the framework formulation for analyzing future risk are the explicit incorporation of reference conditions to avoid additional scenario-based analysis of reference conditions and climate change emissions scenarios. In the case study application, an increase in impervious area from economic development is the LULC change; it generates a 1.1 times increase in average water availability, relative to future climate trends, from increased runoff and decreased transpiration.

Hydrological regime, water availability and land use/land cover change impact on the water balance in a large agriculture basin in the Southern Brazilian Amazon

2021 ◽  
Vol 108 ◽  
pp. 103224
Author(s):  
Tárcio Rocha Lopes ◽  
Cornélio Alberto Zolin ◽  
Rafael Mingoti ◽  
Laurimar Gonçalves Vendrusculo ◽  
Frederico Terra de Almeida ◽  
...  
Keyword(s):  
Land Use ◽  
Land Cover ◽  
Water Balance ◽  
Land Cover Change ◽  
Water Availability ◽  
Hydrological Regime ◽  
Brazilian Amazon ◽  
Land Use Land Cover ◽  
Change Impact

scholarly journals Drought resistance of sugar-cane crop for different levels of water availability in the soil

2014 ◽  
Vol 34 (2) ◽  
pp. 203-210 ◽  
Author(s):  
Fernando da S. Barbosa ◽  
Rubens D. Coelho ◽  
Rafael Maschio ◽  
Carlos J. G. de S. Lima ◽  
Everaldo M. da Silva
Keyword(s):  
Water Balance ◽  
Soil Water ◽  
Water Deficit ◽  
Early Development ◽  
Drought Resistance ◽  
Sugar Cane ◽  
Water Availability ◽  
Sandy Loam ◽  
Final Population ◽  
Different Levels

Soil water availability is the main cause of reduced productivity, and the early development period most sensitive to water deficit. This study aimed to evaluate the drought resistance of the varieties of sugar-cane RB867515 and SP81-3250 during the early development using different levels of water deficit on four soil depths. The experiment was conducted at the Department of Biosystems at Escola Superior de Agricultura "Luiz de Queiroz" (ESALQ/USP) in a greenhouse in soil classified as Oxisol, sandy loam texture (Series "Sertãozinho"). Once exhausted the level of available water in the soil, the dry strength of the studied strains are relatively low. Water balance with values less than -13 mm cause a significant decrease in the final population of plants, regardless of the variety, and values below -35 mm, leads to the death of all plants.

scholarly journals Simulation of future climate scenarios and the impact on the water availability in southern Brazil

2021 ◽  
Vol 43 ◽  
pp. e56026
Author(s):  
Gabriela Leite Neves ◽  
Jorim Sousa das Virgens Filho ◽  
Maysa de Lima Leite ◽  
Frederico Fabio Mauad
Keyword(s):  
Climate Change ◽  
Water Balance ◽  
Water Availability ◽  
Meteorological Data ◽  
Future Climate ◽  
Climate Scenarios ◽  
Southern Brazil ◽  
Climate Data ◽  
Intergovernmental Panel ◽  
The Impact

Water is an essential natural resource that is being impacted by climate change. Thus, knowledge of future water availability conditions around the globe becomes necessary. Based on that, this study aimed to simulate future climate scenarios and evaluate the impact on water balance in southern Brazil. Daily data of rainfall and air temperature (maximum and minimum) were used. The meteorological data were collected in 28 locations over 30 years (1980-2009). For the data simulation, we used the climate data stochastic generator PGECLIMA_R. It was considered two scenarios of the fifth report of the Intergovernmental Panel on Climate Change (IPCC) and a scenario with the historical data trend. The water balance estimates were performed for the current data and the simulated data, through the methodology of Thornthwaite and Mather (1955). The moisture indexes were spatialized by the kriging method. These indexes were chosen as the parameters to represent the water conditions in different situations. The region assessed presented a high variability in water availability among locations; however, it did not present high water deficiency values, even with climate change. Overall, it was observed a reduction of moisture index in most sites and in all scenarios assessed, especially in the northern region when compared to the other regions. The second scenario of the IPCC (the worst situation) promoting higher reductions and dry conditions for the 2099 year. The impacts of climate change on water availability, identified in this study, can affect the general society, therefore, they must be considered in the planning and management of water resources, especially in the regional context

scholarly journals Water Availability and water balance in Erbil Governorate

2006 ◽  
Vol 18 (1) ◽  
pp. 73-87
Author(s):  
Waleed AI-Rijabo ◽  
Sardar Kareem
Keyword(s):  
Water Balance ◽  
Water Availability
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