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Biogas production potential and cost-benefit analysis of harvesting wetland plants (Phragmites australis and Glyceria maxima).Gilson, Eoin January 2017 (has links)
Biogas production from energy crops grown on arable land often competes with food and feed production. Wetland plants offer an alternative source of biomass as well as offering a number of environmental benefits such as nutrient removal from wastewaters, carbon sequestration and reducing the use of mineral fertilizer. The aim of this study is to investigate the effect of harvest time on biogas production of Phragmites australis and Glyceria maxima and to perform a cost-benefit analysis of using these wetland plants as a substrate for biogas production. The results of the batch experiment show that the overall biogas production and specific methane yields of biomass harvested in June was higher than biomass harvested in September due the increased lignocellulosic nature of the more mature September plant. The cost-benefit showed that in Sweden it is not currently profitable to solely use wetland plants for biogas production. For both species the highest costs were seen in the June harvested biomass, this was due to the much higher fresh weight and increased transportation costs. For both species the highest revenues generated were the June harvested biomass, this was due to the higher specific methane yields. It was found that the harvest time that was closest to profitability from both species was the June harvest for Phragmites australis. Although the costs were higher for harvesting in June, this was outweighed by the higher amount of electricity produced for this scenario. If transportation distance was to be increased it could result in September being the favourable harvest time. Therefore, individual circumstances of the farmers could decide which is the optimal harvest time. Although solely using wetland plants for biogas production is not currently profitable, co-digestion and pre-treatment are options to investigate that could change this. Also if a greater financial value is put on the socioeconomic benefits such as increased biodiversity, aesthetic value and global warming mitigation it may be financially viable in the future.
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The interaction between vegetation and near-surface water in a wetland system, Stellenbosch, South AfricaKareko, John K.(John Kariuki) 12 1900 (has links)
Thesis (MSc)--University of Stellenbosch, 2004. / ENGLISH ABSTRACT: Understanding the responses of individual plant communities to variations in
near-surface water levels and to water quality is a step towards determining the critical or
important factors applicable to a Rapid Wetland Assessment System.
This thesis describes and discusses factors associated with wetland plant
communities, with an attempt to predict changes in a wetland system. This study was
initiated with a primary aim of establishing the relationship between plant communities
and the variation in near-surface water levels in areas occupied by various plant
communities in the Middelvlei wetland system at Stellenbosch. A second aim was to
assess whether water quality had an influence on the plant communities.
Seven plant communities are identified and described from this particular wetland
system using standard Braun-Blanquet techniques (Typha capensis Reedswamp; Cyperus
textilis Sedgeland; Pennisetum macrourum Grassland; Juncus effusus Sedgeland;
Cyperus longus Sedgeland; Cliffortia strobilifera Shrubland and Populus canescens
Forest). The Typha capensis Reedswamp community is found in the wettest parts of the
wetlands, with a fluctuation in water table from 0.10 m above surface during the wet
season to 0.43 m below surface during the dry season. The Populus canescens Forest is
actively invading the wetland replacing the wetland species by modifying the wetland
hydrological condition. Water samples from 35 wells, collected on a monthly basis over
11 months, are used to assess sodium, magnesium, potassium, calcium, nitrate and
phosphate, pH, redoxs potencial and dissolved oxygen levels in each community, over
four seasons.
Both multivariate analysis (ANOVA) and regression tree analysis (CART) are
applied to evaluate differences between communities or groups of plant communities on a
seasonal basis. Direct gradient analysis (CCA) is used to determine the relationship
between plant communities and environmental variable gradients.
A wide variation in water quality condition between plant communities is present.
The Typha capensis Reedswamp community is associated with low nutrient levels
(phosphates and nitrates) in all seasons. The Cyperus textilis Sedgeland is associated with low levels of nitrates and high phosphate levels. The Juncus effusus Sedgeland displays
the highest phosphate concentration, occurring in summer, while low nitrate levels occur
in this community during all the seasons.
Dissolved oxygen in the near-surface water in this wetland is at very low
concentrations, and has no significant difference between communities. It plays no major
role in determining the occurrence and distribution of the plant communities.
Most of the water chemical constituents measured in this study are the result of
multiple complex relationships, with constituent variations occurring differently between
communities. A remarkable seasonal distinction in the chemical constituents in different
communities is present.
Despite the complex nature of the relationships between plant communities and
environmental factors, the low species diversity levels through the tendency for single
species dominance and the strong association of these communities with particular
environmental variables, the combination of these factors all add value to the use of
wetland vegetation as a good tool to indicate wetland condition. An effort to understand
wetland plant communities in relation to determining environmental factors would
promote the use of plant communities as user-friendly tools for wetland monitoring and
assessment. / AFRIKAANSE OPSOMMING: Om die reaksies van plantgemeenskappe teenoor variasies in naby-oppervlakte
watervlakke te verstaan, is die eerste krities-belangrike faktor die ontwikkeling van ‘n
sisteem om vleilande vinnig te assesseer. Hierdie studie se basiese mikpunt is om
verwantskappe te soek tussen plantgemeenskappe in die Middelvlei Vleilandsisteem en
wisseling in naby-oppervlak watervlakke. ‘n Sekondêre doel is om te bepaal of daar
enige korrelasie is tussen waterkwaliteit en die plantgemeenskappe teenwoordig in die
vleiland.
Sewe plantgemeenskappe is in hierdie vleilandsisteem geïdentifiseer en beskryf
deur gebruik te maak van standaard Braun-Blanquet tegnieke, naamlik die Typha
capensis Rietmoeras; Cyperus textilis Biesieveld; Pennisetum macrourum Grasveld;
Juncus effusus Biesieveld; Cyperus longus Biesieveld; Cliffortia strobilifera Struikveld
en ‘n Populus canescens Woud. Die Typha capensis Rietmoeras kom in die natste dele
van die vleilande voor, met vrywater wisselling vanaf 0.10 m bo grondoppervlakte,
tydens die nat-seisoen, tot 0.43 m onder grondoppervlakte tydens die droë seisoen. Die
Populus canescens Woud het die grootste wisseling in watervlak vanaf die
grondoppervlakte tot ten minste ‘n diepte van 1.0 m gehad. Dit blyk dat die Populus
canescens Woud besig is om die vleigemeenskappe aktief binne te dring deur die vleiland
uit te droog.
Water is maandeliks, oor 11 maande, uit 35 geperforeerde plastiek pype,
sogenaamde ‘putte’ onttrek, om natrium, magnesium, kalium, kalsium, nitrate en fosfate,
pH, redokspotensiaal en opgeloste suurstof vlakke se seisoenale wisseling te bepaal.
Beide veelvuldige analise (ANOVA) en regressie-analises (CART) is bereken om enige
betekenisvolle verskille tussen plantgemeenskappe te bepaal. Direkte Gradiëntanalise
(CCA) is gebruik om die verwantskap tussen plantgemeenskappe en gradiënte van
omgewingsveranderlikes te bepaal.
Groot variasies in waterkwaliteit tussen plantgemeenskappe is waargeneem. Die
Typha capensis Rietmoeras-gemeenskap is geassosieer met lae voedingstofvlakke (veral
van fosfate en nitrate) in alle seisoene. Die Cyperus textilis Biesieveld-gemeenskap is geassosieer met lae nitraat- en hoë fosfaatvlakke. Die Juncus effusus Biesieveldgemeenskap
vertoon die hoogste fosfaatvlakke, tydens die die somermaande, terwyl die
nitraatvlakke deur al die seisoene ook laag bly.
Opgeloste suurstof in die naby-oppervlakte water in die vleilandsisteem het
deurgaans ‘n lae konsentrasie vertoon met geen betekenisvolle verskille tussen
gemeenskappe nie. Dit speel dus geen belangrike rol in die voorkoms of verspreiding
van die plantgemeenskappe nie
Die meeste van hierdie faktore, gemeet om die waterkwaliteit te bepaal, het
veelvoudige, komplekse verhoudingsverskille, gebaseer veral op konsentrasieverskille,
tussen die gemeenskappe.
Ten spyte van die komplekse verwantskap tussen die plantgemeenskappe en
omgewingsfaktore, is die spesierykheid laag en kom die neiging tot eensoortigedominansie
algemeen in die vleiland-plantgemeenskappe voor. Die sterk assosiasie
tussen die plantgemeenskappe en bepaalde omgewingsveranderlikes voeg aansienlike
waarde daaraan toe om vleilandplantegroei te gebruik as indikator van vleilandtoestand.
‘n Poging om die verwantskappe tussen vleiland-plantgemeenskappe en
omgewingsveranderlikes algemeen te bepaal, sal die gebruikersvriendelike nut van
vleiland-plantgemeenskappe vir vleilandmonitering en assessering duidelik uitwys.
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Effects of Sediment Removal on Vegetation Communities in Prairie Pothole Wetlands in North DakotaSmith, Caitlin Langworthy January 2011 (has links)
The goal of this study was to assess effects of sediment removal on vegetation communities in Prairie Pothole wetlands in North Dakota to determine if this management technique is providing desired results to create conditions for ideal vegetation communities in wetlands that will benefit wildlife. This project consists of vegetation surveys from seasonal wetlands located in Benson, Eddy. Towner. and Wells counties in North Dakota. Three types of wetlands were surveyed: natural (reference), excavated (treatment), and converted cropland. Vegetation surveys were completed in the shallow marsh and wet meadow zones of seasonal wetlands. Sites were sampled using a modified Daubenmire method. Aerial photos were assessed to determine the occurrence of drawdown cycles in wetland sites. Plant communities were analyzed using non-metric multidimensional scaling and multi-response permutation procedure was used to make comparisons between sites. The wet meadow zones and shallow marsh zones of the three types of wetlands were all significantly different (p<0.016) from one another. In general, restored wetlands show vegetation trends that liken natural wetlands while those that have been allowed to recover without restoration tend to be cattail choked. When examining hybrid cattail specifically visual obstruction scores were approximately four times greater in converted cropland sites versus treatment or reference sites. Vegetation composition indicates hydrologic conditions (fresh to brackish conditions) of specific sites and regional distribution are likely influential factors in wetland plant establishment. / North Dakota State University / U.S. Fish and Wildlife Service / Ducks Unlimited
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An investigation into the effect of metals on chlorophyll content and photosynthesis activity of the wetland plant phragmites australis in the lower Diep River, Milnerton, Cape TownAyeni, Olutoyosi Olaide January 2011 (has links)
Thesis (MTech (Environmental Management)))--Cape Peninsula University of Technology, 2011. / A study involving a wetland plant, common reed (Phragmites australis L.) was carried
out along the bank of the lower Diep River and the adjacent soil samples from four
different sites (Milnerton Lagoon, Lower Estuary, Milnerton Bowling Club and
Woodbridge Island), Cape Town, South Africa. The aim was to determine the extent of
metal contamination and its impact on physiological indices.
Results showed that among the metals evaluated, AI and Fe were consistently higher in
all the soil samples (from both river bank and the adjacent soil) followed by Zn, Mn, Pb,
Cu, Cd, Co, Cr and Ni. The concentrations of AI in the river banks ranged between
1214.1 - 3176 mg.kg-1 compared with the adjacent soils, where AI concentration ranged
from 434.8 - 2445.4 mg.kq". The Fe concentrations from the river bank values ranged
from 1136.4 - 4897.2 mg.kg-1 compared with Fe concentrations of the adjacent soil
samples which ranged from 402.2 - 2459.8 mg.kg-1
. Generally, Zn ranged from 2.4 -
211.5 mq.kq"; Mn: 5.5 - 48.05 mg.kq': Pb: 0.97 - 71.7 mg.kq"; Cu: 0.3 - 45.9 mg.kq';
Cd: 0.0 - 9.3 mg.kq": Co: 0.2 - 2.7 mg.kq': Cr: 0.3 - 2.1 mg.kg-1
; and Ni: 0.02 - 2.6
mg.kg-1.
Overall, Ni had the lovest concentrations in the ecosystem. Results also showed that the abundance of metals from plant samples were in the order
of AI > Pb > Cd > Co > Ni > Cr; and for micronutrients, Fe > Mn > Zn > Cu both in the
shoots and roots sampled from all the sites investigated. The values of chlorophylls a, b
and total chlorophyll as well as photosynthesis were significantly higher in the P.
australis plant samples and from the adjacent soil compared with those from the river
bank. These results suggest that contamination of soils and wetland ecosystem by
metals over and above plant requirements may affect the chlorophyll and photosynthesis
rate of the plant thereby undermining the physiological functioning of plants growing
along river systems.
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Testing the Floristic Quality Assessment Index in natural and created wetlands in Mississippi, USAHerman, Brook Danielle. January 2005 (has links)
Thesis (M.S.) -- Mississippi State University. Department of Biological Sciences. / Title from title screen. Includes bibliographical references.
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Comparison of bare root vs. potted plants, species selection, and caging types for restoration of a prairie wetland, and quantitative analysis and descriptive survey of plant communities and associations at Lewisville Lake Environmental Learning Area (LLELA), Lewisville, TXBuckallew, Robin Randolph. Dickson, Kenneth L., January 2007 (has links)
Thesis (Ph. D.)--University of North Texas, May, 2007. / Title from title page display. Includes bibliographical references.
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Selected soil properties and vegetation composition of five wetland systems on the Maputaland Coastal Plain, Kwazulu-NatalPretorius, Mathilde Luïse 28 September 2016 (has links)
South Africa has a few unique and understudied areas of interest regarding wetlands, of which the Maputaland Coastal Plain (MCP) is one. This is regarded as a large gap in scientific knowledge, especially since firstly, the MCP is regarded as a unique area in terms of biodiversity, geology, social history, and ecosystem variety; and secondly, wetlands are a vulnerable, and yet a greatly important ecosystem type in South Africa. Additionally the wetlands on the aeolian derived sandy soils associated with the MCP are problematic to delineate. Although the wetland delineation guideline of DWAF (2005) gives a list of criteria to aid the delineation process on sandy coastal aquifers, this has never been scientifically reviewed. The aim of this study was to investigate how vegetation and soil properties vary down the topographical slope in various wetland types on the MCP. This was done in order to contribute to the knowledge base and understanding of wetlands in this area, as well as to determine whether differences between zones are significant enough to be used as indicators of wetland boundaries. Soil colour was investigated as a possible new delineation indicator. A section is also devoted to commentary on the current wetland delineation procedure on the MCP. This study shows that wetland types on the MCP are very distinct from each other, and therefore broad statements about the soil and vegetation characteristics of wetlands are discouraged. Three substrate types namely high organic-, duplex-, and sandy substrates dominate wetlands on the MCP. These play a major influential role in the general characteristics and function of the wetland types. Contrary to popular belief, redoximorphic accumulation and -depletions do occur on the MCP, but are often inconsistent in their presence. Chemical soil properties were found not to be good indicators of wetland boundaries on the MCP, although certain patterns can be discerned and applied to determine wetland conditions. The main drivers of wetland vegetation are the wetness- and productivity gradients. A few prominent indicator species can be used for the identification of wetland and non-wetland sites specifically on the MCP. Additionally, a relatively underutilised vegetation assessment procedure called Weighted Averaging was investigated, and can in most cases effectively discern between wetland and non-wetland conditions. This is a useful tool to apply in delineation practices in addition to other indicators. Soil colour can be used to successfully indicate wetland boundaries, and therefore be used as an additional wetland indicator. However, the method requires further testing and refinement for different wetland types. In general the vegetation and soil indicators do not correlate perfectly, and therefore delineation by means of one indicator only is greatly discouraged. An investigation of recommended delineation procedures for the MCP shows that new information on the understanding of wetlands in sandy coastal aquifers urgently needs to be disseminated. Approaches such as that of the USDA-NRCS where regionally specific guidelines are designed to be adapted regularly as new information becomes available, as well as the development of sets of hydric indicators specific to problematic areas, are recommended / College of Agriculture and Environmental Sciences / D. Phil. (Environmental Science)
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Phytoremediation of Historic Lead Shot Contaminated Soil, Grand Valley Ranch, Northeast OhioTening Ndifet, Claret Mengwi January 2016 (has links)
No description available.
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Impacts of instream flows on the Colorado River Delta, Mexico : spatial vegetation change analysis and opportunities for restorationZamora-Arroyo, Jose Francisco 07 October 2002 (has links)
Until the 1930s, flows of the Colorado River maintained approximately
781,060 hectares of wetlands in its delta. These wetlands provided important feeding
and nesting grounds for resident and migratory birds as well as spawning and
protection habitat for many fish and other invertebrate species. However, the Delta's
wetlands started to disappear as water was used for agricultural and urban uses in the
United States and Mexico. The 1944 United States-Mexico water treaty, which
allocates 1.8 million m��/year to Mexico, did not define a minimum flow to maintain
the Delta's ecosystems. The resulting degraded Delta lead to the perception in the
1980s that the Delta was a dead ecosystem.
This study investigates whether this "dead Delta" perception is valid. Its
central hypothesis is that regenerated vegetation in riparian and flood plain zones is
associated with surplus river flows during the 1990s. A vegetation analysis, using
satellite imagery and field methods, shows that native trees have regenerated during
the last 20 years, and now account for 23% of vegetation in a 100 km, non-perennial,
stretch of river below the United States-Mexico border. A spatial trend analysis using
multi-temporal data on percent vegetation cover indicates that there are 6,320 hectares
that show a significant increasing trend (p-value<0.05) in vegetation cover, with the
Delta's riparian zone having at least 18% of its area showing this trend.
The study estimates that once in four years February to April flow of 300
million m�� (at 80-120 m��/s) is sufficient to germinate and establish new cohorts of
native trees, and highlights the need for smaller but more periodic flows in order to
maintain wetland areas. It is concluded that there is clear evidence of the resilience of
the Delta's ecosystems and that the "dead Delta" perception is no longer valid. There
exist critical habitat in the Delta that needs to be protected, while there also exist short
and long term opportunities to ecologically enhance and expand current habitat.
Hydrological and ecological studies are needed to estimate specific water
requirements for these areas in order to efficiently target them for immediate and long
term conservation actions. / Graduation date: 2003
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Aspects of the structure and functioning of the vegetation of the Hlatikulu Vlei.Guthrie, Iain Andrew. January 1996 (has links)
Hlatikulu Vlei, situated in the foothills of the Natal Drakensberg, is one of the priority
wetlands in KwaZulu-Natal, occupying an area of 733 Hectares. The importance of
Hlatikulu Vlei lies in its functions to store water, regulate stream flow and attenuate
floods, as well as to provide suitable habitat for wildlife and grazing for livestock.
Hlatikulu Vlei is a threatened system and has suffered the effects of human
mismanagement. Forty-nine percent of the vlei has been classified as disturbed or
destroyed, mainly due to the construction of two large dams and past drainage of vlei to
facilitate pasture planting. The effects of grazing and fire on the plant communities has
been considerably less.
Vegetation communities at Hlatikulu Vlei have similarities with those at Ntabamhlope
Vlei. The main plant communities present at Hlatikulu Vlei are: vlei grassland, sege-meadows,
bulrushes and reedswamp. Species compositions of the mixed sedge and
grass sedge-meadow community have a notably higher species diversity than similar
communities sampled at Ntabamhlope Vlei and the mires at Highmoor.
Soil type and moisture content are shown to be the most significant environmental
factors determining the distribution of plant communities and species within the vlei.
A wetland re-establishment and rehabilitation programme in the Hlatikulu Crane and
Wetland Sanctuary has been effective in allowing many wetland plants to become reestablished.
The sanctuary communities bear greater similarity to the sedge and rush
sedge-meadow community, than the mixed sedge and grass sedge-meadow communities
that were originally present. This is also reflected in the seed bank.
All three Southern African crane species (Blue, Wattled and Crowned Crane) and
fourteen species of waterfowl have been recorded in the Hlatikulu Crane and Wetland
Sanctuary since the wetland rehabilitation programme. The waterfowl play a role in the
dispersal of seeds into the sanctuary, particularly those of Schoenoplectus decipiens and Eleocharis dregeana and are in part responsible for the return of certain wetland plants
to the sanctuary.
The flooding of soils, the fluctuating water level and the soil type related to hummocks
and to channels are shown to be responsible for the location of Cyperus denudatus,
Arundinella nepalensis and Aristida junciformis in differing positions in the channels
and on the hummocks and are also responsible for the maintenance and functioning of
the hummocks and channels.
Seed banks on the hummocks are similar to seed banks in the channels, however the
extant vegetation on the hummocks is distinctly different to that in the channels.
Certain species represented in the channel seed bank are being excluded from surviving
to maturity. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 1996.
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