Les plantes envahissantes sont considérées comme l'une des plus grandes menaces sur les espèces, mais leurs impacts sur les amphibiens demeurent peu connus. L’objectif de ce projet est de déterminer l’effet de l’établissement du roseau commun (Phragmites australis) sur la répartition des amphibiens et sur leur développement larvaire. Il est présumé que cette plante s'accapare l'espace et les ressources disponibles en produisant une importante biomasse, qu’elle peut modifier l’hydrologie des marais et la structure des communautés d’amphibiens. J’ai évalué les facteurs influençant la répartition des amphibiens selon les caractéristiques des étangs et du paysage dans 50 sites envahis ou non à divers degrés. Des expériences ont également été menées afin d’étudier les répercussions de trois densités de roseau sur des têtards de la Grenouille des bois (Lithobates sylvaticus) et sur la qualité de son habitat. Mes résultats suggèrent que le roseau à forte densité ralentit le développement larvaire de la grenouille des bois et influence les assemblages phytoplanctoniques. Cependant, il n’y a aucune relation entre la densité de la plante et la survie, la morphologie des têtards et les caractéristiques biotiques et abiotiques de l’eau. Dans notre aire d’étude, le paysage autour des étangs a une plus grande influence sur la répartition des amphibiens que l'établissement du roseau. Toutefois, la probabilité d’assèchement est plus élevée lorsque la plante est établie en grande quantité, ce qui, si l’envahissement s’intensifie, aura un effet néfaste sur la survie des têtards et mettra en péril la persistance des populations. / Invasive plants are considered one of the greatest threats to species, but their impact on amphibians is still poorly understood. The objective of this project is to determine the effect of the establishment of common reed (Phragmites australis) on amphibian distribution and larval development. It is thought that this plant monopolizes space and resources by producing a large biomass, and may alter wetland hydrology and amphibian community structure. I evaluated the factors influencing amphibian distribution according to the characteristics of ponds and the surrounding landscape in 50 sites invaded or not by reeds to varying degrees. Experiments were also conducted to study the impacts of three reed densities on wood frog tadpoles (Lithobates sylvaticus) and the quality of their habitat. My results suggest that high reed density slows wood frog larval development and influences phytoplankton assemblages. However, there is no relationship between, plant density and survival, tadpole morphology and water biotic and abiotic characteristic. In our study area, the landscape surrounding ponds has a greater influence on amphibian distribution than does reed establishment. However, the desiccation probability is higher when the plant is established in high quantities, which, if the invasion intensifies, will have an adverse effect on tadpole survival and therefore population persistence.

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal

Despite a positive contribution to economic – social development, the growth of piggeries has caused heavily environmental pollution. Currently, treated wastewater of pig farms unfortunately does not meet the national discharge standards yet. This paper presents some research results on the removing COD, nitrogen and phosphorus in piggery wastewater after anaerobic (biogas) process at pilot scale by the combined system using Phragmites australis, Cyperus alternifolius, Vetiveria zizanioides and Eichhornia crassipes. The experimental results showed that the wastewater loading rate of 47.35 l/m2.day with initial concentrations of 203.24 mg COD/l, 111.94 mgTN/l and 13.61 mgTP/l gave removal efficiency of 71.66 %, 79.26 % and 69.65 %, respectively. Thus, the removed quantity of total nitrogen (TN) and total phosphorus (TP) was of 4201.35 mg TN/m2.day và 448.76mg TP/m2.day. The obtained results indicated that the flow wetland system, using Phragmites australis, Cyperus alternifolius, Vetiveria zizanioides and Eichhornia crassipes has a rather high COD, TN and TP removal efficiency with simple operation so that it could be feasible if applied for treating pig wastewater. However, the system should be functioned longer for taking data and for evaluating its stability. / Mặc dù có những đóng góp tích cực cho sự phát triển kinh tế - xã hội, việc phát triển chăn nuôi lợn đã gây ô nhiễm môi trường nghiêm trọng. Hiện nay, nước thải chăn nuôi lợn từ các cơ sở chăn nuôi sau xử lý vẫn chưa đáp ứng được các tiêu chuẩn thải của quốc gia và tiêu chuẩn ngành. Bài báo này trình bày kết quả nghiên cứu về khả năng loại bỏ COD, nitơ (N) và phôtpho (P) trong nước thải chăn nuôi lợn đã qua xử lý bằng hầm biogas của hệ thống phối hợp cây Sậy, Thủy Trúc, cỏ Vetiver và Bèo Tây ở qui mô pilot. Kết quả thực nghiệm ở tải lượng 47,35 l/m2.ngày, với COD, tổng nitơ (TN) và tổng phôtpho (TP) đầu vào trung bình là 203,24 mg/l, 111,94 mg/l và 13,61 mg/l, tương ứng, thì hiệu suất xử lý lần lượt là 71,66 %; 79,26 % và 69,65 %. Như vậy lượng TN và TP loại bỏ là 4201,35 mgN/m2.ngày và 448,76 mgP/m2.ngày. Kết quả nhận được cho thấy hệ thống sử dụng cây Sậy, Thủy Trúc, cỏ Vetiver và Bèo Tây có hiệu quả loại bỏ COD, TN và TP khá cao trong khi vận hành đơn giản nên có triển vọng áp dụng trong điều kiện thực tế để xử lý nước thải chăn nuôi lợn. Tuy nhiên để đánh giá tính ổn định, hệ thống cần được hoạt động với thời gian lâu dài hơn.

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.

Magister Scientiae - MSc / The aim of this study was to use plants to determine the degree of heavy metal contamination in water and sediments in order to effectively monitor and provide possible recommendation to improve the water quality in the aquatic ecosystem of the Bottelary River.

No description available.

Saltmarshes are highly valued habitats but the majority of the Eden Estuary's saltmarsh was buried under sea defences and ad hoc rubbish dumps during the last century. Without saltmarsh, the degraded shoreline may be even more vulnerable to rising sea levels and increased wave and tidal energy. This study investigated planting native saltmarsh species, common in the estuaries of Eastern Scotland, to restore saltmarsh development and sedimentation to the Eden Estuary's shoreline. The survival and growth of the sedge Bolboschoenus maritimus (Sea Club-rush) and the grasses Phragmites australis (Common Reed) and Puccinellia maritima (Common Saltmarsh Grass) were compared in planting trials. These were seeded or transplanted onto unvegetated upper mudflats in front of eroded P. maritima saltmarsh and a disused rubbish dump. The longer term sustainability of this practice was assessed by comparing sediment deposition and surface elevation in the transplant sites, natural saltmarsh and upper unvegetated mudflats. B. maritimus outperformed P. australis and P. maritima. Springtime, high density planting was successful, whereas seeds, planting in autumn and low density planting failed. Growth in the transplanted B. maritimus sites was relatively slow for the first three years but subsequently overtook growth of the seaward edge of natural B. maritimus marsh. Sediment was not deposited on natural P. maritima and was low on upper unvegetated mudflats and in young transplant sites. Most deposition occurred in four year old sites of B. maritimus. Sediment surface elevation in natural P. maritima remained constant throughout the year, but increased in all the other sites during the summer. The upper mudflat was the only site to erode during winter. A significant, positive association was found between tide height and sediment deposition, while winds from the south-east were associated with significantly more deposition than winds from the south-west. The direct planting of saltmarsh vegetation has restored a valuable and rapidly disappearing habitat to the degraded shoreline of the Eden Estuary. The low-cost and simplicity of this restoration practice give it great potential as a sustainable coastal management option that should be explored in other Scottish estuaries. This form of restoration could help to increase the resilience and reduce the vulnerability of degraded shorelines to climate change and rising sea levels.

Vertical flow constructed wetlands (VF CWs) are becoming increasingly popular for onsite wastewater treatment due to their high oxygen transfer capacity and high nitrification rates. However, there are still some question marks regarding (1) how the treatment performance of VF CWs is affected by design and operational parameters, and (2) the treatment processes happening inside the wetland bed as the wastewater percolates through. In this study, we investigated the effects of filter media (coarse sand or fine gravel), dosing regime (hourly with 4 mm or bi-hourly with 8 mm) and plant presence (with or without Phragmites australis) on the  treatment performance and concentration depth profiles of pollutant removal in six pilot-scale VF CWs treating primary treated domestic wastewater. Grab samples of wastewater were collected every 2-3 weeks during 5 months and analyzed for organic matter, suspended solids, nitrogen and E. coli. We found that sand beds performed better than gravel beds for removal of all pollutants except total nitrogen, although for long term operation gravel may be less susceptible to clogging. The overall treatment performance was not affected by different dosing regimes, but the concentration depth profiles showed that smaller and more frequent doses led to more pollutant removal in the upper part of the beds. The presence of plants was moderately important for the removal of ammonium, but had no effect on other pollutants.

To foster the practical development of constructed wetlands used for wastewater treatment in Turkey, a pilot-scale subsurface constructed wetland system (90 m2) was designed to treat the domestic wastewater produced by 60 PE living in the residential area of METU. In summer 2001, two parallel sets of hybrid wetland systems (vertical flow connected with horizontal flow) with identical design configuration, but with different fill media (blast furnace granulated iron slag and gravel) were built on the old sludge-drying bed of the abandoned wastewater treatment plant of METU, which has not been operating since the 1990s. Wetland cells were planted with common reed (Phragmites australis). The main objective of this research was to quantify the effect of different filter media on the removal performance of subsurface flow constructed wetlands in the prevailing climate of Ankara. Thus, slag-filled and gravel-filled vertical flow wetlands were operated identically with pre-settled domestic wastewater (3 m3.d-1) at a hydraulic loading rate of 110 mm.d-1 for 12 months, intermittently. According to the first year results, annual average removal efficiencies for the slag and gravel wetland cells were as follows: TSS (63% &amp / 59%), COD (47% &amp / 44%), NH4+-N (88% &amp / 53%), TN (44% &amp / 39%), PO43--P (44% &amp / 1%) and TP (45% &amp / 4%). The slag-filled vertical flow system removed phosphorus and ammonium efficiently than the gravel-filled system due to the differences in physical structures and chemical compositions of the fill media, and the different aerobic and anaerobic environments within the wetland cells. These results indicated that the well-designed constructed wetlands could also be used for secondary and tertiary treatment in Turkey, successfully.

Invasive plants can outcompete native plants, replacing diverse plant communities with monocultures, which can negatively impact the whole ecosystem. One invasive plant, Phragmites australis, has invaded wetlands across North America. In Utah’s Great Salt Lake, it has greatly reduced the area of native plants that are important habitat for migratory birds. Here we describe experiments that assess multiple treatments for Phragmites removal and evaluate the return of native plants after Phragmites management. The treatments were applied to Phragmites patches at two scales (small 1/4-acre plots and large 3-acre plots) and across multiple sites to evaluate how patch size and environmental differences can influence the plants that return after Phragmites removal. The treatments (applied over 3 years and monitored two more) compared two different herbicides (glyphosate and imazapyr) and different herbicide and mowing timings. The treatments evaluated in the large patch study were 1.) untreated control 2.) fall glyphosate, winter mow, 3.) summer imazapyr, winter mow, 4.) summer glyphosate, winter mow. The treatments evaluated in the small patch study included treatments 1-4 above plus 5.) summer mow, fall glyphosate, 6.) summer mow, then black plastic solarization. In the small patches, we also monitored the seeds in the soil to assess how Phragmites management treatments can change the densities of Phragmites and native seeds. Fall glyphosate treatments were superior for Phragmites cover reduction. After the initial treatment, summer herbicide and mow treatments reduced Phragmites seed production, while fall glyphosate did not. Phragmites seeds were plentiful in the soil but were reduced following three years of all herbicide treatments. Native plant recovery following Phragmites management was extremely variable across sites. Sites with high soil moisture had better Phragmites removal and more native plants. But when flooding was deep, native plants were rare. Native seed density in the soil did not change due to Phragmites management, but soil seed densities were different across sites, which influenced native plant recruitment. Phragmites was removed more effectively and native plants returned in greater numbers in small patches compared with large. This was because small patches were typically near established native plant communities, which likely provided more native plant seeds and had hydrology that was less disturbed by human activity. In sites where native plants do not return after Phragmites management, practitioners may need to try revegetation with native plant seeds to restore important native plant communities.