Special Issue "Ecohydrology of Woodlands and Savannas"

A special issue of Water (ISSN 2073-4441). This special issue belongs to the section "Aquatic Systems—Quality and Contamination".

Deadline for manuscript submissions: closed (31 August 2018).

Special Issue Editors

Prof. Dr. Bradford P. Wilcox
E-Mail Website
Guest Editor
Department of Rangeland Ecology and Management, Texas A&M University, College Station, TX 77843-2126, USA
Interests: watershed management; ecohydrology; hydrology of drylands; streamflow; erosion; runoff
Prof. Dr. Chris B. Zou
E-Mail Website
Guest Editor
Department of Natural Resource Ecology & Management, Oklahoma State University, Stillwater, OK 74078, USA
Interests: ecohydrology; water relation in savanna and woodland; wildland hydrology; water resources conservartion; ecosystem management

Special Issue Information

Dear Colleagues,

Savannas, woodlands, and shrublands are expanding globally in a process described as “woody plant encroachment”. Change in vegetation physiognomy from herbaceous to woody dominance has important but not necessarily well understood implications for the water cycle. This Special Issue is focused on providing a state-of-the-art understanding and description of our current understanding of ecohydrology issues in savannas and woodlands. We are particularly interested in papers that provide a comprehensive synthesis of a topic related to ecohydrology of savannas and woodlands.

Prof. Dr. Bradford Paul Wilcox
Prof. Dr. Chris B. Zou
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Water is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2000 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • savannas
  • woodlands
  • ecohydrology
  • runoff
  • erosion
  • water balance
  • transpiration
  • evapotranspiration
  • groundwater
  • streamflow
  • woody plant encroachment

Published Papers (7 papers)

Order results
Result details
Select all
Export citation of selected articles as:

Research

Jump to: Review

Open AccessArticle
Stomatal Conductance Responses of Acacia caven to Seasonal Patterns of Water Availability at Different Soil Depths in a Mediterranean Savanna
Water 2018, 10(11), 1534; https://doi.org/10.3390/w10111534 - 27 Oct 2018
Cited by 1 | Viewed by 1219
Abstract
Soil water availability controls plant productivity in seasonally dry ecosystems, although plant water use at different soil depths and times is, to the best of our knowledge, not clearly understood. Environmental variables at the canopy level and the soil volumetric water content (VWC) [...] Read more.
Soil water availability controls plant productivity in seasonally dry ecosystems, although plant water use at different soil depths and times is, to the best of our knowledge, not clearly understood. Environmental variables at the canopy level and the soil volumetric water content (VWC) at five different soil depths were continuously recorded for three years (2011–2014) in an Acacia caven savanna site in central Chile. Stomatal conductance ( g s ) was measured every hour during daytime for 42 days distributed across the study period. Values of g s were weakly controlled by photosynthetically active radiation, vapor pressure deficit, and leaf temperature when considering the whole series. The variance proportion being explained increased from 5% to 20% if the whole series was partitioned into a dry and a wet season. According to the above, A. caven exhibited a more anisohydric behavior than previously thought. When we added the VWC in the root zone, to the g s atmospheric variables model, R2 increased to 47% when separately considering the dry and wet seasons. However, we did not find a differentiated use of water in the root zone, but instead a joint activity of the radicular system within the top 100 cm of the soil controlling g s . Full article
(This article belongs to the Special Issue Ecohydrology of Woodlands and Savannas)
Show Figures

Figure 1

Open AccessArticle
Soil Moisture, Grass Production and Mesquite Resprout Architecture Following Mesquite Above-Ground Mortality
Water 2018, 10(9), 1243; https://doi.org/10.3390/w10091243 - 14 Sep 2018
Cited by 4 | Viewed by 1100
Abstract
Honey mesquite (Prosopis glandulosa) is an invasive native woody plant in the southern Great Plains, USA. Treatments used to slow the invasion rate have either killed the plant (“root-kill”) or killed above-ground tissue (“top-kill”). Top-killing provides temporary suppression, but stimulates multi-stemmed regrowth. This [...] Read more.
Honey mesquite (Prosopis glandulosa) is an invasive native woody plant in the southern Great Plains, USA. Treatments used to slow the invasion rate have either killed the plant (“root-kill”) or killed above-ground tissue (“top-kill”). Top-killing provides temporary suppression, but stimulates multi-stemmed regrowth. This study from north central Texas quantified soil moisture, grass production and mesquite resprout architecture following a mechanical clearing treatment that top-killed mesquite (cleared) compared to untreated mesquite woodland (woodland) over a 10-year period. During an extreme drought at 5 and 6 years post-clearing, soil moisture at 60-cm depth became lower in cleared than in woodland, suggesting that, as early as 5 years after top-kill, water use by regrowth mesquite could be greater than that by woodland mesquite. Perennial grass production was greater in cleared treatments than in woodland treatments in all years except the extreme drought years. Mesquite regrowth biomass increased numerically each year and was independent of annual precipitation with one exception. During the year 5 and 6 drought, mesquite stopped lateral expansion of larger stems and increased growth of smaller stems and twigs. In summary, top-killing mesquite generated short-term benefits of increased grass production, but regrowth created potentially negative consequences related to soil moisture. Full article
(This article belongs to the Special Issue Ecohydrology of Woodlands and Savannas)
Show Figures

Figure 1

Open AccessArticle
Single Session of Chiseling Tillage for Soil and Vegetation Restoration in Severely Degraded Shrublands
Water 2018, 10(6), 755; https://doi.org/10.3390/w10060755 - 09 Jun 2018
Cited by 1 | Viewed by 1361
Abstract
While tillage of agricultural lands has been used extensively, its utilization for restoring degraded semi-natural lands is rare. This study was conducted in the arid southern Israel in a shrubland which has faced severe degradation processes over time, including soil erosion and compaction, [...] Read more.
While tillage of agricultural lands has been used extensively, its utilization for restoring degraded semi-natural lands is rare. This study was conducted in the arid southern Israel in a shrubland which has faced severe degradation processes over time, including soil erosion and compaction, and negation of vegetation recovery. In 2014, research plots were established for assessing the impact of a single chiseling session on the ecosystem’s restoration capacity. The study treatments included deep chiseling (35 cm), shallow chiseling (20 cm), and control (no-tillage). Data on spontaneously-established vegetation was collected one, two, and three years after the plots’ establishment, and soil data was collected once—three years after the plots’ establishment. Assessments of the vegetation parameters revealed a general similarity between the two chiseling treatments, which were generally better than those of the no-till plots. The soil properties revealed generally greater soil quality under the two chiseling treatments than that under the control plots, and a somewhat better soil quality for the deep chiseling than that for the shallow chiseling. Overall, results of this study show that in severely degraded lands, self-restoration processes are hindered, negating the effectiveness of passive restoration practices, and necessitating active intervention practices to stimulate restoration processes. Full article
(This article belongs to the Special Issue Ecohydrology of Woodlands and Savannas)
Show Figures

Figure 1

Open AccessArticle
Plant Harvesting Impacts on Soil Water Patterns and Phenology for Shrub-encroached Grassland
Water 2018, 10(6), 736; https://doi.org/10.3390/w10060736 - 05 Jun 2018
Cited by 1 | Viewed by 1309
Abstract
Harvesting is a common method in grassland management. With shrub encroachment into grassland, special hydrological and physiological dynamics probably occur in the shrub-grass coexisted ecosystem after harvesting, which remains largely unclear. Therefore, this study aims to identify potential effects of harvesting on soil [...] Read more.
Harvesting is a common method in grassland management. With shrub encroachment into grassland, special hydrological and physiological dynamics probably occur in the shrub-grass coexisted ecosystem after harvesting, which remains largely unclear. Therefore, this study aims to identify potential effects of harvesting on soil moisture pattern, phenology dynamics, and water utilization in a shrub encroached grassland. We monitored soil water for a year beneath the Caragana microphylla canopy and interspace grassland after harvesting. The results showed that the soil water content increased under shrubs and grass patches after harvesting, especially under later ones. The water storage in soil of 0–100 cm depth increased by 18.9 mm under grass but only 5.5 mm under shrubs. Harvesting also decreased the difference of water storage between shrubs and grass from 19.1 to 5.7 mm. More snowmelt compensation, less evapotranspiration, shorter growing season, and higher water use efficiency may jointly contribute to the water recovery of harvesting soil. This study contributes novel evidence to the ecohydrological impacts of harvesting on shrub-grass co-existed ecosystems, shows application value in controlling shrub encroachment process and provides fundamental insights for the further study on soil water dynamics of similar ecosystems worldwide. Full article
(This article belongs to the Special Issue Ecohydrology of Woodlands and Savannas)
Show Figures

Figure 1

Review

Jump to: Research

Open AccessFeature PaperReview
Impact of Eastern Redcedar Proliferation on Water Resources in the Great Plains USA—Current State of Knowledge
Water 2018, 10(12), 1768; https://doi.org/10.3390/w10121768 - 01 Dec 2018
Cited by 7 | Viewed by 2074
Abstract
In the Great Plains of the central United States, water resources for human and aquatic life rely primarily on surface runoff and local recharge from rangelands that are under rapid transformation to woodland by the encroachment of Eastern redcedar (redcedar; Juniperus virginiana) [...] Read more.
In the Great Plains of the central United States, water resources for human and aquatic life rely primarily on surface runoff and local recharge from rangelands that are under rapid transformation to woodland by the encroachment of Eastern redcedar (redcedar; Juniperus virginiana) trees. In this synthesis, the current understanding and impact of redcedar encroachment on the water budget and water resources available for non-ecosystem use are reviewed. Existing studies concluded that the conversion from herbaceous-dominated rangeland to redcedar woodland increases precipitation loss to canopy interception and vegetation transpiration. The decrease of soil moisture, particularly for the subsurface soil layer, is widely documented. The depletion of soil moisture is directly related to the observed decrease in surface runoff, and the potential of deep recharge for redcedar encroached watersheds. Model simulations suggest that complete conversion of the rangelands to redcedar woodland at the watershed and basin scale in the South-central Great Plains would lead to reduced streamflow throughout the year, with the reductions of streamflow between 20 to 40% depending on the aridity of the climate of the watershed. Recommended topics for future studies include: (i) The spatial dynamics of redcedar proliferation and its impact on water budget across a regional hydrologic network; (ii) the temporal dynamics of precipitation interception by the herbaceous canopy; (iii) the impact of redcedar infilling into deciduous forests such as the Cross Timbers and its impact on water budget and water availability for non-ecosystem use; (iv) land surface and climate interaction and cross-scale hydrological modeling and forecasting; (v) impact of redcedar encroachment on sediment production and water quality; and (vi) assessment and efficacy of different redcedar control measures in restoring hydrological functions of watershed. Full article
(This article belongs to the Special Issue Ecohydrology of Woodlands and Savannas)
Show Figures

Figure 1

Open AccessReview
Spatial and Temporal Variability of the Impacts of Pinyon and Juniper Reduction on Hydrologic and Erosion Processes Across Climatic Gradients in the Western US: A Regional Synthesis
Water 2018, 10(11), 1607; https://doi.org/10.3390/w10111607 - 08 Nov 2018
Cited by 8 | Viewed by 1526
Abstract
Pinyon (Pinus spp.) and juniper (Juniperus spp.) woodlands are an important vegetation type in the Great Basin, Colorado Plateau, and southwestern desert regions of the western US that is undergoing substantial changes associated with land management, altered disturbance regimes, and climate [...] Read more.
Pinyon (Pinus spp.) and juniper (Juniperus spp.) woodlands are an important vegetation type in the Great Basin, Colorado Plateau, and southwestern desert regions of the western US that is undergoing substantial changes associated with land management, altered disturbance regimes, and climate change. We synthesized literature on the ecohydrologic impacts of pinyon and juniper tree reductions across plot to watershed scales, short- and long-term periods, and regional climatic gradients. We found that the initial plot- to hillslope-scale ecohydrologic and erosion impacts of tree reduction on pinyon and juniper woodlands by fire, mechanical tree removal, or drought depend largely on: (1) the degree to which these perturbations alter vegetation and ground cover structure, (2) initial conditions, and (3) inherent site attributes. Fire commonly imparts an initial increased risk for hillslope runoff and erosion that degrades over time with vegetation and ground cover recovery whereas tree reductions by mechanical means pose fewer initial negative ecohydrologic impacts. Tree reduction by either approach can enhance understory vegetation and improve site-level ecohydrologic function over time, particularly on sites with an initially favorable cover of native herbaceous vegetation and a cool-season precipitation regime. Understory vegetation and ground cover enhancements appear to increase ecohydrologic resilience of some woodland communities to disturbances such as drought, fire, and insect infestations. In contrast, intensive land use, prolonged drought or repeated burning associated with invasions of fire-prone grasses can propagate long-term site degradation through persistent elevated runoff and erosion rates. Our synthesis suggests the annual precipitation requirement for increases in plot- to hillslope-scale soil water availability for herbaceous enhancement through tree removal likely ranges from 200–400 mm for sites in the Great Basin and northern Colorado Plateau (cool-season precipitation regimes), and, although suggested with great uncertainty, likely exceeds 400 mm for woodlands with rain-dominated precipitation regimes in the southwestern US. Overall, literature is inconclusive regarding tree reduction impacts on watershed-scale changes in groundwater and streamflow. To date, there is little evidence that drought-related changes to vegetation in pinyon and juniper woodlands substantially affect watershed-scale water availability and streamflow at the annual time scale. Our synthesis identifies key knowledge gaps to overcome in improving understanding of the ecohydrologic and erosion impacts of broadly occurring pinyon and juniper tree reductions in the western US. Full article
(This article belongs to the Special Issue Ecohydrology of Woodlands and Savannas)
Show Figures

Figure 1

Open AccessReview
Woody Plant Encroachment Impacts on Groundwater Recharge: A Review
Water 2018, 10(10), 1466; https://doi.org/10.3390/w10101466 - 17 Oct 2018
Cited by 18 | Viewed by 2794
Abstract
Woody plant encroachment has profound impacts on the sustainable management of water resources in water-limited ecosystems. However, our understanding of the effects of this global phenomenon on groundwater recharge at local and regional scales is limited. Here, we reviewed studies related to (i) [...] Read more.
Woody plant encroachment has profound impacts on the sustainable management of water resources in water-limited ecosystems. However, our understanding of the effects of this global phenomenon on groundwater recharge at local and regional scales is limited. Here, we reviewed studies related to (i) recharge estimation methods; (ii) mechanisms by which woody plants impact groundwater recharge; (iii) impacts of woody plant on recharge across different soil and geology; (iv) hydrological repercussions of woody plant removal; and (v) research gaps and needs for groundwater studies. We identified six different methods: water balance, water table, isotopes, chloride mass balance, electrical geophysical imaging, and modeling were used to study the impact of woody encroachment on groundwater. Woody plant encroachment could alter soil infiltration rates, soil water storage, transpiration, interception, and subsurface pathways to affect groundwater recharge. The impact is highly variable, with the extent and the magnitude varying across the soil, substrate, plant cover, and topographic locations. Our review revealed mixed effects of woody plant removal on groundwater recharge. Studies of litter interception, root water uptake, soil moisture dynamics, and deep percolation along with the progression of woody plant encroachment are still limited, warranting further experimental studies focusing on groundwater recharge. Overall, information about woody plant encroachment impacts on groundwater resources across a range of scales is essential for long-range planning of water resources. Full article
(This article belongs to the Special Issue Ecohydrology of Woodlands and Savannas)
Show Figures

Figure 1

Back to TopTop