Habitat preference and reproductive traits of a major Australian riparian tree species (Casuarina cunninghamiana)

2001 ◽  
Vol 49 (6) ◽  
pp. 705 ◽  
Author(s):  
A. R. Woolfrey ◽  
P. G. Ladd
Keyword(s):  
Population Structure ◽  
Water Table ◽  
Seedling Establishment ◽  
Reproductive Traits ◽  
High Water ◽  
River Channel ◽  
Sandy Substrate ◽  
Casuarina Cunninghamiana ◽  
Eastern Australia ◽  
Seed Fall

The population structure and reproductive biology of the river oak (Casuarina cunninghamiana) were studied along the Murrumbidgee River on the Southern Tablelands of eastern Australia. The species has cone-like infructescences but is not serotinous, with samaras released when they are mature. Samaras were mostly distributed by wind close to female trees but were also carried by water. The first year of study (1985) appeared to be a mast year for seed production with much lower seed fall in the following year. Seedling establishment was spatially very variable, mostly under female canopies and appeared earlier on soil within the river channel than on the bank. Turnover was high and seedlings in the river channel generally died after being inundated. Most trees were within 3 m of the mean river level. However, the total distribution of adults was within the envelope of maximum floods in the area but establishment was not dependent on floods. The population structure was the result of yearly recruitment, although episodic events (floods, drought) may enhance or decrease establishment. Pot-trial results paralleled the field situation with substrate and water-table level not affecting germination of seed but strongly influencing seedling growth. Plants grew best on cobble substrates under a low water-table regime and poorly on cobbles with high water and sandy substrate under all water-table levels. Cobble banks seemed the best substrate for growth within the river channel and establishment may be prolific. Less-abundant seedling establishment occurred upslope but controls over this were not investigated.

Groundwater recharge from rainfall and irrigation in the campaspe river basin

Soil Research ◽  
1991 ◽  
Vol 29 (5) ◽  
pp. 651 ◽  
Author(s):  
FHS Chiew ◽  
TA Mcmahon
Keyword(s):  
Groundwater Recharge ◽  
River Basin ◽  
Water Table ◽  
High Water ◽  
Shallow Aquifer ◽  
Management Tool ◽  
Management Options ◽  
Salinity Control ◽  
Eastern Australia ◽  
Recharge Rates

Reliable estimates of groundwater recharge are required for effective evaluation of management options for salinity control and high water-tables in the Riverine Plain of south-eastern Australia. This paper provides a brief description of the integrated surface and groundwater modelling approach used to estimate regional recharge rates and presents the recharge rates estimated for the Campaspe River Basin. The integrated model is a powerful management tool as it can predict the relationship between rainfall, irrigation, recharge and rises in the water-table levels. The model predicted that approximately 15% of irrigation water recharges the shallow aquifer. Approximately 6% of rainfall contributes to recharge in the irrigated areas while 4 to 5% of rainfall becomes recharge in the dryland areas. Rainfall makes a greater contribution in the irrigation areas compared to the dryland areas because irrigation predisposes the soil to recharge from rainfall. The water-table levels in the irrigation areas are currently rising at approximately 0.14 m yr-1. This rate of rise will increase faster than the increase in irrigation applications.

scholarly journals Structure, Diversity, and Environmental Determinants of High-Latitude Threatened Conifer Forests

Forests ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 775
Author(s):  
Carlos Esse ◽  
Francisco Correa-Araneda ◽  
Cristian Acuña ◽  
Rodrigo Santander-Massa ◽  
Patricio De Los Ríos-Escalante ◽  
...  
Keyword(s):  
Water Table ◽  
Environmental Variables ◽  
National Park ◽  
High Water ◽  
Forest Communities ◽  
Competitive Effect ◽  
Forest Patches ◽  
Last Glaciation ◽  
The World ◽  
Local Topography

Pilgerodendron uviferum (D. Don) Florin is an endemic, threatened conifer that grows in South America. In the sub-Antarctic territory, one of the most isolated places in the world, some forest patches remain untouched since the last glaciation. In this study, we analyze the tree structure and tree diversity and characterize the environmental conditions where P. uviferum-dominated stands develop within the Magellanic islands in Kawésqar National Park, Chile. An environmental matrix using the databases WorldClim and SoilGrids and local topography variables was used to identify the main environmental variables that explain the P. uviferum-dominated stands. PCA was used to reduce the environmental variables, and PERMANOVA and nMDS were used to evaluate differences among forest communities. The results show that two forest communities are present within the Magellanic islands. Both forest communities share the fact that they can persist over time due to the high water table that limits the competitive effect from other tree species less tolerant to high soil water table and organic matter. Our results contribute to knowledge of the species’ environmental preference and design conservation programs.

The effect of population structure on growth patterns in the woody goldenrod Solidago pauciflosculosa

1983 ◽  
Vol 61 (7) ◽  
pp. 1955-1958 ◽  
Author(s):  
Marvin P. Pritts ◽  
James F. Hancock
Keyword(s):  
Population Structure ◽  
Seedling Establishment ◽  
Reproductive Output ◽  
Plant Biomass ◽  
Growth Patterns ◽  
Dispersion Pattern ◽  
Allocation Patterns ◽  
Total Plant Biomass ◽  
Total Plant ◽  
Two Populations

The population structure and growth patterns of two populations of Solidago pauciflosculosa, a woody goldenrod, were investigated. Populations consisted of even-aged contagious patches of individuals, a dispersion pattern likely caused by the periodic appearance of microsites suitable for seedling establishment. The density of individuals within the even-aged clumps varied considerably and was correlated with total plant biomass and reproductive output. Density was not correlated with either reproductive or nonreproductive allocation patterns.

Soil behavior and related effects in the Peru earthquake of May 31, 1970

1971 ◽  
Vol 61 (3) ◽  
pp. 579-590 ◽  
Author(s):  
William Enkeboll
Keyword(s):  
Water Table ◽  
High Water ◽  
Soil Behavior ◽  
High Water Table ◽  
Water Conditions ◽  
Degree Of Damage ◽  
Soil And Water

abstract Soil and water conditions had an effect on the degree of damage to structures. Most structures were located on alluvium with a high water table. Settlements occurred in dike and causeway fill in Chimbote harbor. Severe problems to communication occurred in some areas through embankment failures and road slides.

scholarly journals Response of the Snowy River Estuary to two environmental flows

2015 ◽  
Vol 127 (2) ◽  
pp. 28
Author(s):  
Errol J. McLean ◽  
Jon B. Hinwood
Keyword(s):  
Fresh Water ◽  
Peak Flow ◽  
Environmental Flows ◽  
River Estuary ◽  
Environmental Flow ◽  
River Channel ◽  
Salinity Gradients ◽  
Tasman Sea ◽  
Eastern Australia ◽  
Major River

The Snowy River is a major river in south-eastern Australia, discharging to the Tasman Sea via a barrier estuary, with its entrance constricted by marine sands. Since the construction of the Snowy Mountains Scheme, river flows have not been sufficient to maintain the river channel. A program of environmental flow releases (EFR) is returning water to the river to restore the fluvial reaches and is now trialling flow regimes that may also benefit the estuarine reaches. This paper documents the response of the estuarine segments of the Snowy River to two EFRs; the release in 2010 was designed to scour the upper reaches of the Snowy River while the larger 2011 release was intended to extend the scouring downstream. For each release, the effects on the entrance morphology, tides and salinity through the flow peak and recovery are described. Each EFR caused minor increases in depth and very minor longshore movement of the entrance channel, although each EFR had been preceded by a larger fresh flow that would have scoured the channels. The small increase in fresh water inflow in the 2010 EFR pushed salinity contours seawards and steepened vertical salinity gradients. The larger inflow in the 2011 EFR purged the upper estuary of saltwater. After the peak flow, salinity recovery was rapid in the principal estuarine channels but took weeks where poorly connected wetlands could store fresh flood waters. Critical flows for scouring the entrance and purging salinity are estimated.

scholarly journals Partitioning CO<sub>2</sub> net ecosystem exchange fluxes on the microsite scale in the Lena River Delta, Siberia

2018 ◽  
Author(s):  
Tim Eckhardt ◽  
Christian Knoblauch ◽  
Lars Kutzbach ◽  
Gillian Simpson ◽  
Evgeny Abakumov ◽  
...  
Keyword(s):  
Water Table ◽  
Net Ecosystem Exchange ◽  
Growing Season ◽  
Arctic Tundra ◽  
High Water ◽  
Water Levels ◽  
River Delta ◽  
Lena River ◽  
Hydrological Conditions ◽  
Lena River Delta

Abstract. Arctic tundra ecosystems are currently facing rates of amplified climate change. This is critical as these ecosystems store significant amounts of carbon in their soils, which can be mineralized to CO2 and CH4 and released to the atmosphere. To understand how the CO2 net ecosystem exchange (NEE) fluxes will react to changing climatic conditions, it is necessary to understand the individual responses of the physiological processes contributing to CO2 NEE. Therefore, this study aimed: (i) to partition NEE fluxes at the soil-plant-atmosphere interface in an arctic tundra ecosystem; and (ii) to identify the main environmental drivers of these fluxes. Hereby, the NEE fluxes were partitioned into gross primary productivity (GPP) and ecosystem respiration (Reco) and further into autotrophic (RA) and heterotrophic respiration (RH). The study examined flux data collected during the growing season in 2015 using closed chamber measurements in a polygonal tundra landscape in the Lena River Delta, northeastern Siberia. The measured fluxes on the microscale (1 m–10 m) were used to model the NEE, GPP, Reco, RH, RA and net ecosystem production (NPP) over the growing season. Here, for the first time, the differing response of in situ measured RA and RH fluxes from permafrost-affected soils to hydrological conditions have been examined. It was shown that low RA fluxes are associated to a high water table, most likely due to the submersion of mosses, while an effect of water table fluctuations on RH fluxes was not observed. Furthermore, this work found the polygonal tundra in the Lena River Delta to be a sink for atmospheric CO2 during the growing season. Spatial heterogeneity was apparent with the net CO2 uptake at a wet, depressed polygon center being more than twice as high as that measured at a drier polygon rim. In addition to higher GPP fluxes, the differences in NEE between the two microsites were caused by lower Reco fluxes at the center compared to the rim. Here, the contrasting hydrological conditions caused the CO2 flux differences between the microsites, where high water levels lad to lower decomposition rates due to anoxic conditions.

scholarly journals Spontaneous revegetation of a peatland in Manitoba after peat extraction: diversity of plant assemblages and restoration perspectives

Botany ◽  
2018 ◽  
Vol 96 (11) ◽  
pp. 779-791 ◽  
Author(s):  
Félix Gagnon ◽  
Line Rochefort ◽  
Claude Lavoie
Keyword(s):  
Water Table ◽  
Plant Cover ◽  
High Water ◽  
Point Of View ◽  
Water Table Level ◽  
Peat Extraction ◽  
Peatland Restoration ◽  
Water Ph ◽  
Plant Assemblages ◽  
A Site

There are very few studies on the spontaneous revegetation of cutover fens or bogs from which peat has been extracted to the minerotrophic layers. Most peatlands with fen-type residual peat have problems regenerating a plant cover satisfactorily from a restoration point of view. We nevertheless found a site (Moss Spur, Manitoba, Canada) presenting a substantial and diversified spontaneous plant cover. We estimated that the site would provide insights about natural revegetation processes operating in peatlands. Vegetation assemblages and environmental conditions were surveyed 19 years after extraction activities ceased. Moss Spur has densely revegetated (163 plant species, vegetation cover of 94%) with minimal human assistance. However, the composition of plant assemblages varies considerably across the site, depending on certain abiotic variables, particularly water pH, water table level, and the thickness of the residual peat layer. Moss Spur was remarkably wet considering the past peat extraction activities and the absence of active rewetting procedures. The high water table level may in part explain the successful revegetation. However, plant assemblages were not of equal quality from a restoration perspective. Some assemblages were highly diversified, and especially those dominated by Scirpus cyperinus, a species that should be further considered in peatland restoration projects to direct the recovery of the peatland towards a natural fen species composition.

scholarly journals Evaluating the influence of water table depth on transpiration of two vegetation communities in a lake floodplain wetland

2016 ◽  
Vol 47 (S1) ◽  
pp. 293-312 ◽  
Author(s):  
Xiuli Xu ◽  
Qi Zhang ◽  
Yunliang Li ◽  
Xianghu Li
Keyword(s):  
Water Table ◽  
Growth Stage ◽  
High Water ◽  
Water Table Depth ◽  
Floodplain Wetlands ◽  
Floodplain Wetland ◽  
Vegetation Communities ◽  
High Water Table ◽  
Potential Transpiration ◽  
Main Growth

Groundwater plays an important role in supplying water to vegetation in floodplain wetlands. Exploring the effect of water table depth (WTD) on vegetation transpiration is essential to increasing understanding of interactions among vegetation, soil water, and groundwater. In this study, a HYDRUS-1D model was used to simulate the water uptake of two typical vegetation communities, Artemisia capillaris and Phragmites australis, in a floodplain wetland (Poyang Lake wetland, China). Vegetation transpiration was compared for two distinct hydrological conditions: high water table (2012) and low water table (2013). Results showed that vegetation transpiration in the main growth stage (July–October) was significantly influenced by WTD. Under high water table conditions, transpiration of A. capillaris and P. australis communities in the main growth stage totaled 334 and 735 mm, respectively, accounting for over 90% of the potential transpiration. Under low water table conditions, they decreased to 203 and 510 mm, respectively, due to water stress, accounting for merely 55% of the potential transpiration. Scenario simulations found different linear relationships between WTD and the ratio of groundwater contribution to vegetation transpiration. An increase of 1 m in WTD in the main growth stage may reduce the ratio by approximately 25%.

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