Groundwater use by dominant tree species in tropical remnant vegetation communities

2006 ◽  
Vol 54 (2) ◽  
pp. 155 ◽  
Author(s):  
A. P. O'Grady ◽  
P. G. Cook ◽  
P. Howe ◽  
G. Werren
Keyword(s):  
Soil Water ◽  
Water Use ◽  
Tree Species ◽  
Temporal Patterns ◽  
Terrestrial Vegetation ◽  
Spatial And Temporal Patterns ◽  
Groundwater Use ◽  
Vegetation Communities ◽  
Remnant Vegetation ◽  
Water Potential Measurements

Defining groundwater dependence and water-use requirements of terrestrial vegetation represents a significant challenge to water-resources managers. Terrestrial vegetation may exhibit complex spatial and temporal patterns of groundwater dependence. In this study we have assessed the sources of water used by dominant tree species in remnant vegetation of Pioneer Valley, Mackay, in northern Queensland. Water use by tree species was determined by sapflow techniques and the sources of water were investigated by using a combination of isotopic and water-potential measurements. Within the remnant vegetation communities of the Pioneer Valley there were complex patterns of water use and water-resource partitioning. However, all communities within the study showed some degree of groundwater use. Riparian communities that were reliant on groundwater discharge for maintenance of river baseflow exhibited high species diversity and complex forest structure and different species within these communities accessed a range of water sources including shallow soil water, river water and groundwater. In contrast, the woodlands and open forest were principally reliant on soil water. Although, species such as Corymbia clarksoniana appeared to be reliant on groundwater for their dry-season water-use requirements. This study demonstrated use of groundwater by remnant vegetation communities in the Pioneer Valley but determination of groundwater dependence requires a better understanding of the temporal patterns of water use and sources of water used by each species.

scholarly journals Field spatial and temporal patterns of soil water content and bulk density changes

2006 ◽  
Vol 63 (1) ◽  
pp. 55-64 ◽  
Author(s):  
Luís Carlos Timm ◽  
Luiz Fernando Pires ◽  
Renato Roveratti ◽  
Robson Clayton Jacques Arthur ◽  
Klaus Reichardt ◽  
...  
Keyword(s):  
Water Content ◽  
Bulk Density ◽  
Soil Water ◽  
Soil Water Content ◽  
Soil Surface ◽  
Temporal Patterns ◽  
Temporal Changes ◽  
Spatial And Temporal Patterns ◽  
Wetting And Drying ◽  
Wetting And Drying Cycles

Soil water content (theta) and bulk density (rhos) greatly influence important soil and plant processes, such as water movement, soil compaction, soil aeration, and plant root system development. Spatial and temporal variability of theta and rhos during different periods of the year and different phases of crops are of fundamental interest. This work involves the characterization of spatial and temporal patterns of theta and rhos during different climatic periods of year, aiming to verify whether there are significant temporal changes in rhos at the soil surface layer when submitted to wetting and drying cycles. The field experiment was carried out in a coffee plantation, Rhodic Kandiudalf soil, clayey texture. Using a neutron/gamma surface probe, theta and rhos were measured meter by meter along a 200 m spatial transect, along an interrow contour line. During the wet period there was no difference of spatial patterns of theta while during the dry period differences were observed, and can be associated to precipitation events. It was also observed that there are rhos temporal changes at the soil surface along the studied period as a consequence of the in situ wetting and drying cycles.

Spatial and temporal patterns of seed attack and germination in a large-seeded neotropical tree species

Oecologia ◽  
1999 ◽  
Vol 119 (2) ◽  
pp. 208-218 ◽  
Author(s):  
David S. Hammond ◽  
Valerie K. Brown ◽  
Roderick Zagt
Keyword(s):  
Tree Species ◽  
Temporal Patterns ◽  
Spatial And Temporal Patterns ◽  
Neotropical Tree

Groundwater use by riparian vegetation in the wet - dry tropics of northern Australia

2006 ◽  
Vol 54 (2) ◽  
pp. 145 ◽  
Author(s):  
Anthony P. O'Grady ◽  
Derek Eamus ◽  
Peter G. Cook ◽  
Sebastien Lamontagne
Keyword(s):  
Water Use ◽  
Tree Species ◽  
Riparian Vegetation ◽  
Xylem Sap ◽  
Basal Area ◽  
Dry Season ◽  
Riparian Forests ◽  
Deciduous Tree ◽  
Wet Season ◽  
Groundwater Use

Within Australia and globally there is considerable concern about the potential impacts of groundwater extraction on ecosystems dependent on groundwater. In this study we have combined heat pulse and isotopic techniques to assess groundwater use by riparian vegetation along the Daly River in the Northern Territory. The riparian forests of the Daly River exhibited considerable structural and floristic complexity. More than 40 tree species were recorded during vegetation surveys and these exhibited a range of leaf phonologies, implying complex patterns of water resource partitioning within the riparian forests. Water use was a function of species and season, and stand water use varied between 1.8 and 4.1 mm day–1. In general, however, water use tended to be higher in the wet season than during the dry season, reflecting the contribution to stand water use by dry-season deciduous tree species. There was a strong relationship between stand basal area and stand water use in the wet season, but the strength of this relationship was lower in the dry season. The amount of groundwater use, as determined by analysis of deuterium concentrations in xylem sap, was principally a function of position in the landscape. Trees at lower elevations, closer to the river, used more groundwater than trees higher on the levees. By using a combination of techniques we showed that riparian vegetation along the Daly River was highly groundwater dependent and that these water-use requirements need to be considered in regional management plans for groundwater.

scholarly journals Source apportionment of water use during vegetation succession on the Loess Plateau, China

2018 ◽  
Author(s):  
Chang Enhao ◽  
Li Peng ◽  
Li Zhanbin ◽  
Xiao Lie ◽  
Xu Guoce ◽  
...  
Keyword(s):  
Soil Water ◽  
Water Use ◽  
Loess Plateau ◽  
Soil Layer ◽  
Dry Season ◽  
Chinese Government ◽  
The Loess Plateau ◽  
Bothriochloa Ischaemum ◽  
Vegetation Communities ◽  
Successional Development

Background. The Chinese government implemented the largest environmental recovery plan in the 1990s, the Grain for Green Project, on the Loess Plateau to prevent soil erosion. Extensive areas of cultivated land were abandoned and then gradually restored with communities of native vegetation. Little is known, however, about the successional development of these communities and their strategies of water use. Methods. We collected soil and root samples from four vegetation communities at different stages of succession (Artemisia capillaris, A. sacrorum, Bothriochloa ischaemum and Lespedeza davurica) in the dry and wet seasons of 2015 in the Wangmaogou watershed of the Wuding River. Results. Both the root systems and soil-water contents tended to increase with successional development and fluctuated with changes of the dry and wet seasons. Isotopic analysis indicated that the thawing of winter snow during the dry season in April provided sufficient soil water. The vegetation communities only used the water in the 0-20 cm soil layer during the early successional stage. This range increased to 0-100 cm as the succession developed, with strong seasonal variation; water was accessed from deeper soil during the dry season, and water was accessed from shallower soil during the wet season. Discussion. Antecedent rainfall, soil-water content and root distribution strongly influenced the use of water in all four vegetation communities. In the process of restoration and succession of vegetation communities, the behavior characteristics and water absorption strategies of the root system are the important theoretical basis for optimizing the selection of species and accelerating the speed of ecological restoration in Chinese Loess Plateau.

scholarly journals Spatial-and temporal-patterns of global soil heterotrophic respiration in terrestrial ecosystems

2019 ◽  
Author(s):  
Xiaolu Tang ◽  
Shaohui Fan ◽  
Manyi Du ◽  
Wenjie Zhang ◽  
Sicong Gao ◽  
...  
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Temporal Patterns ◽  
Heterotrophic Respiration ◽  
Spatial And Temporal Patterns ◽  
Carbon Loss ◽  
Global Land ◽  
Global Soil ◽  
Soil Heterotrophic Respiration

Abstract. Soil heterotrophic respiration (RH) is one of the largest and most uncertain components of the terrestrial carbon cycle, directly reflecting carbon loss from soil to the atmosphere. However, high variations and uncertainties of RH existing in global carbon cycling models require an urgent development of data-derived RH dataset. To fill this knowledge gap, this study applied Random Forest (RF) algorithm – a machine learning approach, to (1) develop a globally gridded RH dataset and (2) investigate its spatial- and temporal-patterns from 1980 to 2016 at the global scale by linking field observations from the Global Soil Respiration Database and global environmental drivers – temperature, precipitation, soil water content, etc. Finally, a globally gridded RH dataset was developed covering from 1980 to 2016 with a spatial resolution of half degree and a temporal resolution of one year. Globally, the average annual RH was 57.2 ± 0.6 Pg C a−1 from 1980 to 2016, with a significantly increasing trend of 0.036 ± 0.007 Pg C a−2. However, the temporal trend of the carbon loss from RH varied with climate zones that RH showed significant increasing trends in boreal and temperate areas, in contrast, such trend was absent in tropical regions. Temperature driven RH dominated 39 % of global land and was mainly distributed at a high latitude. While the areas dominated by precipitation and soil water content were mainly semi-arid and tropical areas, accounting for 36 % and 25 % of the global land, respectively, suggesting variations in the dominance of environmental controls on the spatial patterns of RH. The developed globally gridded RH dataset will further aid in understanding of the mechanisms of global soil carbon dynamics, serving as a benchmark to constrain global vegetation models. The dataset is publicly available at https://doi.org/10.6084/m9.figshare.8882567 (Tang et al., 2019a).

scholarly journals Elevated atmospheric CO2 concentration improves water use efficiency and growth of a widespread Cerrado tree species even under soil water deficit

2019 ◽  
Vol 33 (3) ◽  
pp. 425-436 ◽  
Author(s):  
João Paulo Souza ◽  
Nayara Magry Jesus Melo ◽  
Alessandro Dias Halfeld ◽  
Kamilla I. C. Vieira ◽  
Bruno Luan Rosa
Keyword(s):  
Water Use Efficiency ◽  
Soil Water ◽  
Water Deficit ◽  
Water Use ◽  
Tree Species ◽  
Co2 Concentration ◽  
Atmospheric Co2 ◽  
Soil Water Deficit ◽  
Elevated Atmospheric Co2 ◽  
Use Efficiency

scholarly journals Effects of groundwater abstraction on two keystone tree species in an arid savanna national park

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e2923 ◽  
Author(s):  
Eleanor Shadwell ◽  
Edmund February
Keyword(s):  
Soil Water ◽  
Water Use ◽  
Water Table ◽  
Tree Species ◽  
Dry Season ◽  
Leaf Water ◽  
Groundwater Abstraction ◽  
Stomatal Regulation ◽  
Water Potentials ◽  
Large Trees

BackgroundIn arid systems with no surface water, deep boreholes in ephemeral river beds provide for humans and animals. With continually increasing infrastructure development for tourism in arid wildlife parks such as the Kgalagadi Transfrontier Park in southern Africa, we ask what effects increased abstraction may have on large trees. Large trees in arid savannas perform essential ecosystem services by providing food, shade, nesting sites and increased nutrients for many other plant and animal species and for this are regarded as keystone species.MethodsWe determine seasonal fluctuations in the water table while also determining the water source for the dominant large tree species in the Auob and Nossob rivers in the Park. We also determine the extent to which these trees are physiologically stressed using leafδ13C, xylem pressure potentials, specific leaf area and an estimate of canopy death. We do this both upstream and downstream of a low water use borehole in the Auob River and a high water use borehole in the Nossob River.ResultsOur results show that the trees are indeed using deep groundwater in the wet season and that this is the same water used by people. In the dry season, trees in the Auob downstream of the active borehole become detached from the aquifer and use more isotopically enriched soil water. In the Nossob in the dry season, all trees use isotopically enriched soil water, and downstream of the active borehole use stomatal regulation to maintain leaf water potentials. These results suggest that trees in the more heavily utilised Nossob are under more water stress than those trees in the Auob but that trees in both rivers demonstrate physiological adaptation to the changes in available water with smaller heavier leaves, no significant canopy dieback and in the dry season in the Nossob stomatal regulation of leaf water potentials.DiscussionAn increase in abstraction of groundwater particularly at the Nossob borehole may cause an additional draw down of the water table adding to the physiological stress demonstrated in our study. The managers of the Kgalagadi Transfrontier Park have a mandate that includes biodiversity conservation. To fulfil this mandate, upper and lower thresholds for groundwater abstraction that allow for an adequate ecological reserve have to be determined.

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