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.

La phénologie des arbres caducifoliés en forêt guyanaise (5° de latitude nord) : illustration d'un déterminisme à composantes endogène et exogène

1994 ◽  
Vol 72 (12) ◽  
pp. 1843-1857 ◽  
Author(s):  
Denis Loubry
Keyword(s):  
Key Words ◽  
Tree Species ◽  
Rain Forest ◽  
Tropical Rain Forest ◽  
French Guiana ◽  
Dry Season ◽  
Deciduous Tree ◽  
Leaf Fall

The French Guianan forest is an evergreen rain forest that contains approximately 100 deciduous tree species. The taxonomical distribution of the deciduous character is widely spread, and its presence or absence among some taxa, as well as its ancient origin, are arguments in favour of an endogenous origin. Leaf-fall periodicity was studied on a sample of 500 trees during a 2-year period. Periodicity is annual and seasonal. It is not correlated to rainfall and not linked to the occurrence of a dry season. It seems closely correlated to photoperiodical variations, even though those variations are weak (35 min at latitude 5°30′N). However, each tree has its own periodicity for leaves shedding. Therefore, there is a paradox between seasonality and individual periodicity of leaf fall. The existence of this paradox leads us to consider the hypothesis of an integration of endogenous and exogenous components in the determination of leaf-fall periodicity. Key words: deciduousness, French Guiana, phenology, photoperiodism, tree, tropical rain forest.

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 The influence of riparian vegetation on leaf litter inputs to Boreal Shield streams: implications for partial-harvest logging in riparian reserves

2009 ◽  
Vol 39 (5) ◽  
pp. 917-927 ◽  
Author(s):  
Elisa A. Muto ◽  
David P. Kreutzweiser ◽  
Paul K. Sibley
Keyword(s):  
Linear Regression ◽  
Leaf Litter ◽  
Riparian Vegetation ◽  
Basal Area ◽  
Deciduous Tree ◽  
Deciduous Trees ◽  
Partial Harvest ◽  
Conifer Needles ◽  
Distance Weighted ◽  
Boreal Shield

Litter inputs to headwater streams were measured to characterize and describe input patterns to the streams and to quantify the relationships between leaf litter inputs and surrounding riparian characteristics in Boreal Shield forests. Our goal was to provide information on litter inputs to streams in the Boreal Shield to determine if partial-harvest logging of commercial trees within riparian reserves has the potential to cause significant changes to litter inputs. Total leaf litter comprised 87% deciduous leaves and 13% conifer needles during the June to October periods. Commercial deciduous tree species accounted for approximately 50% of total deciduous leaf litter inputs. Distance-weighted deciduous basal area was the best predictor of overstorey deciduous litter (r2 = 0.597, P = <0.001), indicating that the size, abundance, and proximity of deciduous trees to streams are important to deciduous litter inputs. Leaf litter inputs to Boreal Shield streams are strongly influenced by surrounding riparian vegetation and can be effectively predicted by stem basal area. A linear regression model based on commercial deciduous tree basal area is presented that can be useful to determine the number of trees to retain within a riparian area to maintain leaf litter inputs at or near preharvest levels.

Patterns and Implications of Hydrologic Regime Change in Chongwe River, Zambia

2016 ◽  
Vol 8 (3) ◽  
pp. 1 ◽  
Author(s):  
Moses Ngongo Chisola ◽  
Michal Kuráž
Keyword(s):  
Water Use ◽  
Dry Season ◽  
Significant Trend ◽  
Series Data ◽  
Hydrologic Regime ◽  
Wet Season ◽  
Significance Level ◽  
Flow Duration ◽  
Flow Duration Curves ◽  
Gauging Station

Conflicts regarding water use have emerged in some small irrigation dominated peri-urban catchments in Zambia; Chongwe being one such catchment. Despite these conflicts suggesting a change in hydrologic regime, the nature of the changes and their drivers has not been adequately investigated. The Mann Kendall trend test and Flow Duration Curves were used to investigate changes in hydro-climatic time series data in Chongwe upper catchment for the period 1955-2006. Although the results reviewed a significant upward trend in temperature at 0.05 significance level, there is no significant trend in rainfall. Annual and seasonal runoff at the upstream located Ngwerere weir reviewed significant upward trends at 0.05 significance level. This increased runoff which is attributed to sewer water discharge and increased imperviousness is abstracted for agricultural activities upstream. In this regard, results reviewed no significant trend in runoff at the outlet gauging station (Chongwe 5025). However, analysis of the Flow Duration Curves at this outlet gauging station indicated an increase in wet season flows and a reduction in dry season flows for the 1990-2006 period. These results suggest that human activities in the upstream parts of the catchments could be the major contributing factors to the changes in flow regime, hence the ensuing upstream vs downstream water use conflicts. However, there is still excess runoff in the wet season that could be harvested by downstream water users in order to offset the deficit in downstream dry season flows.

scholarly journals Structure of the montane taiga forests of West Khentii, Northern Mongolia

2012 ◽  
Vol 58 (No. 2) ◽  
pp. 45-56 ◽  
Author(s):  
M. Mühlenberg ◽  
J. Appelfelder ◽  
H. Hoffmann ◽  
E. Ayush ◽  
K.J. Wilson
Keyword(s):  
Tree Species ◽  
Basal Area ◽  
Fire Regimes ◽  
Elevational Gradient ◽  
Deciduous Tree ◽  
Forest Types ◽  
Northern Mongolia ◽  
Southern Border ◽  
Composition Structure ◽  
Siberian Pine

Studies were undertaken to investigate the composition, structure and diversity of four different types of North Mongolian montane forest near the southern border of the taiga. These forest types, classified as willow-poplar, larch-birch, spruce-fir and Siberian-pine forests, were found to be significantly different with respect to the elevational gradient. In the study area, two fire regimes could be distinguished at lower and drier elevations, frequent surface fires resulted in less diverse forests comprising coniferous species, which in their adult form were found to be fire-resistant, burn-colonizing and light-demanding deciduous tree species. In contrast, the forests colonizing the moist, higher elevations and shaded slopes had a higher diversity of tree species with greater basal area, higher proportion of deadwood, and more regenerating trees; here the coniferous shade trees experienced infrequent but destructive treetop fires. Overall, our results showed that the four forest types differed in composition according to the tree species, diameter and height classes. &nbsp; &nbsp;

A field experiment to determine the effect of dry-season irrigation on vegetative and reproductive traits in the wet-deciduous tree Bonellia nervosa

2019 ◽  
Vol 36 (1) ◽  
pp. 29-35
Author(s):  
Octavio Sánchez ◽  
Mauricio Quesada ◽  
Rodolfo Dirzo ◽  
Carl D. Schlichting
Keyword(s):  
Field Experiment ◽  
Water Availability ◽  
Irrigation Treatment ◽  
Reproductive Traits ◽  
Dry Season ◽  
Leaf Phenology ◽  
Deciduous Tree ◽  
Wet Season ◽  
Seasonally Dry ◽  
Carbohydrate Concentration

AbstractSeasonally dry tropical forests (SDTFs) stand out by the diversity of phenological patterns used by plants to deal with dry periods. Although the predominant phenological pattern is dry deciduousness, in Mesoamerican SDTFs the heliophilous tree species Bonellia (formerly Jacquinia) nervosa displays an unusual inverted leaf phenology, producing and holding leaves through the dry season while becoming deciduous in the rainy season. Applying a dry season irrigation field experiment (no water, low watering, high watering), we studied the consequences of contrasting water availability from a phenological plasticity response perspective. Contrary to our expectations, our results show no effect of irrigation treatment on leaf phenology. In addition, mid-day twig water potential showed no significant differences across treatments, but reproductive phenological responses varied among treatments: canopy flowering per cent decreased gradually until the beginning of the wet season in all treatments; meanwhile canopy fruit per cent showed a significant decline under low irrigation. Finally, non-structural carbohydrate concentration (starch) was significantly higher in the high irrigation treatment. Our results showed that inverted leaf phenology remains unaffected regardless of supplemental water availability, and suggest a reallocation of non-structural carbohydrates to fruits and seeds in high-irrigation treatments. Given the current and expected increase in extreme drought events, investigations on the responses of trees of different phenologies, including those of inverted leafing such as Bonellia nervosa, are warranted.

Dry-Season Distribution and Ecology of Carettochelys-Insculpta (Chelonia, Carettochelydidae) in Kakadu-National-Park, Northern Australia

1989 ◽  
Vol 16 (3) ◽  
pp. 323 ◽  
Author(s):  
a Georges ◽  
R Kennett
Keyword(s):  
Riparian Vegetation ◽  
National Park ◽  
Aquatic Macrophytes ◽  
Fine Sand ◽  
Black Soil ◽  
Dry Season ◽  
Wet Season ◽  
Distribution And Ecology ◽  
Ecological Basis ◽  
Great Scope

Carettochelys insculpta is widely distributed (though not necessarily abundant) in Kakadu National Park during the dry season, occupying permanent billabongs from the black-soil plains to the base of the escarpment. High population densities were found in the upper reaches of the South Alligator drainage (33.8 turtles ha-1; 227.4 kg ha-1) and are interpreted as dry-season concentrations of turtles that would occupy a much wider range in the wet season. C. insculpta nest in clean, fine sand adjacent to water from mid July to early November. About 15 hard-shelled spherical eggs were laid in a shallow chamber (maximum depth 18-21 cm) between 1.0 and 3.7 m from water, with the height above water ranging from 0.4 to 0.7 m. The nests suffered heavy predation from varanid lizards. The turtles are general omnivores that draw upon a wide variety of food, including algae, aquatic macrophytes, fruits, seeds and leaves of riparian vegetation, aquatic macroinvertebrates, and carrion. Its catholic tastes provide great scope for opportunism, and its diet varies greatly in accordance with the foods available from locality to locality. The ecological basis for the restricted global distribution of C. insculpta is unclear since the species appears to have very broad habitat requirements.

scholarly journals Root carbohydrate storage in young saplings of an Amazonian tidal várzea forest before the onset of the wet season

1994 ◽  
Vol 8 (2) ◽  
pp. 129-139 ◽  
Author(s):  
Fabio Rubio Scarano ◽  
José Henrique Cattânio ◽  
Robert M.M. Crawford
Keyword(s):  
Tree Species ◽  
Dry Season ◽  
Carbohydrate Content ◽  
Adaptive Mechanism ◽  
Wet Season ◽  
Glucose Content ◽  
Palm Trees ◽  
Carbohydrate Storage ◽  
Flood Regime ◽  
Root Starch

Root starch and glucose content were measured for young saplings of 18 Amazonian tidal várzea tree species during a dry season. The pattern of carbohydrate storage depended on the type of plant involved and soil topography which is directly linked to flood regime. Most plants showed high root carbohydrate content at this point in the dry season, however, several typically flood-tolerant species (particularly palm trees) presented a low root carbohydrate content, suggesting a strategy of acquiring reserves during the wet season to survive the dry season, when depletion occurs. Plant survival in these flood-prone forests seems to be the result of more than only one adaptive mechanism.

scholarly journals Non-structural carbohydrates mediate seasonal water stress across Amazon forests

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Caroline Signori-Müller ◽  
Rafael S. Oliveira ◽  
Fernanda de Vasconcellos Barros ◽  
Julia Valentim Tavares ◽  
Martin Gilpin ◽  
...  
Keyword(s):  
Water Stress ◽  
Tree Species ◽  
Tree Mortality ◽  
Soluble Sugar ◽  
Dry Season ◽  
Future Climate Change ◽  
Wet Season ◽  
Dry Conditions ◽  
Almost All

AbstractNon-structural carbohydrates (NSC) are major substrates for plant metabolism and have been implicated in mediating drought-induced tree mortality. Despite their significance, NSC dynamics in tropical forests remain little studied. We present leaf and branch NSC data for 82 Amazon canopy tree species in six sites spanning a broad precipitation gradient. During the wet season, total NSC (NSCT) concentrations in both organs were remarkably similar across communities. However, NSCT and its soluble sugar (SS) and starch components varied much more across sites during the dry season. Notably, the proportion of leaf NSCT in the form of SS (SS:NSCT) increased greatly in the dry season in almost all species in the driest sites, implying an important role of SS in mediating water stress in these sites. This adjustment of leaf NSC balance was not observed in tree species less-adapted to water deficit, even under exceptionally dry conditions. Thus, leaf carbon metabolism may help to explain floristic sorting across water availability gradients in Amazonia and enable better prediction of forest responses to future climate change.

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