The key to a successful wetland design is duplicating the hydroperiod of the desired wetland type. Dense wetland vegetation affects surface water flow rates by increasing flow resistance. Prior research represented the vegetation as individual stems; however, many wetland species grow in clumps. Therefore, the objectives of this study were to investigate the effect of clumping vegetation on flow resistance and to develop a prediction equation for use in wetland design. A 6-m by 1-m by 0.4-m recirculating flume was planted with mature common rush, Juncus effusus, a common emergent wetland plant. Three different flow rates (3, 4, and 5 L/s) and three different tailgate heights (0, 2.5, and 5 cm) were used to simulate a variety of wetland conditions. Plant spacing and clump diameter were varied (20 and 25 cm, 8 and 12 cm, respectively). Friction factors ranged from 9 to 40 and decreased with increasing plant density. Non-dimensional parameters determined through Buckingham Pi analysis were used in a regression analysis to develop a prediction model. Results of the regression analysis showed that the fraction of vegetated occupied area (P) was most significant factor in determining friction factor. / Master of Science

published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management

Understanding the link between indicator species and their environment is imperative to managing and conserving anthropogenically-altered ecosystems. Seasonally-pulsed wetlands are uniquely complex ecosystem where water-level fluctuations shape trophic interactions. Anthropogenic manipulation of water-level fluctuation threatens the integrity of these systems worldwide. Wading birds, a group of species sensitive to landuse changes and fluctuating habitat conditions, serve as important indicators for wetland health. I used wading birds in the Everglades, as a model system to address the challenges of environmental restoration within an ecosystem heavily impacted by anthropogenic activities. Specifically, I 1) identified the nesting response of Great Egret (Ardea alba), White Ibis (Eudocimus albus), and Wood Stork (Mycteria americana) to hydrologically-mediated changes in food availability and 2) quantified spatiotemporal foraging-habitat selection of Great Egrets, White Ibis, and Wood Storks to fluctuating hydrologic conditions. Collectively, model selection results suggest food availability, generated through dynamic hydrological conditions, is a strong predictor of the abundance of nesting birds in a given year. Great egret and white ibis produce the highest nests numbers in years when the frequency of days of rising water is low. Wood stork nest numbers are the highest in years with high prey production coupled with continuous prey availability. My study of resource selection indicated wading birds select foraging sites based on similar hydrologic parameters, but the response varies by species. Wood storks are more likely to forage in shallow cells (< 10 cm) drying with high recession rates (0.5-1.5 cm/day), and long time since last drydown (600 days). White ibises selected foraging cells with relatively shallow water depths (0-15 cm), intermediate recession rates (0.5-1.0 cm/day), and long time since drydown (600 days). Great egrets selected foraging cells with a wider range of water depths (0-20 cm) where recession rates were lower (0.5 cm/day). All species are more likely to forage in cells where water has not increased by more than 3 cm in the previous two weeks. These differences in resource selections correspond to morphological and behavioral differences in the species, whereby wood storks were more constrained hydrologically and would be more affected by water-level manipulation. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2017. / FAU Electronic Theses and Dissertations Collection

A challenge to ensure the health of wading bird populations is to have a better understanding of the altered habitats that we must now consider part of their natural history. Throughout their range endangered Wood Storks (Mycteria americana) have been reported to forage in ditches, a disparate category of linear man-made waterways. In a 52-kmP 2 P study area on the east coast of central Florida, the characteristics of hydrologically diverse ditches were quantified, and their use by Wood Storks documented during their non-breeding season. Logistic regression analyses were carried out using the ditch characteristics as independent variables and Wood Stork presence/absence as the dependent variable. This study confirms the use of these marginal wetlands, and identifies the significance of emergent vegetation on the foraging habitat selection of Wood Storks in the dry season. / by Eleanor K. Van Os. / Thesis (M.S.)--Florida Atlantic University, 2008. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2008. Mode of access: World Wide Web.

Wong, Man Shan Michelle. / Thesis submitted in: November 2006. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (leaves 148-167). / Abstracts in English and Chinese. / Acknowledgements --- p.I / Abstract --- p.III / Table of contents --- p.VI / List of Tables --- p.X / List of Figures --- p.XI / List of Plates --- p.XIV / Chapter Chapter 1 --- Introduction / Chapter 1.1 --- Wetlands --- p.1 / Chapter 1.2 --- Importance of wetlands --- p.3 / Chapter 1.3 --- Wetland plants --- p.7 / Chapter 1.4 --- Adaptations of wetland plants to flooding --- p.7 / Chapter 1.5 --- Effects of hydrology on wetland plants --- p.13 / Chapter 1.6 --- Other factors affecting plant growth in wetlands --- p.16 / Chapter 1.7 --- Wetlands in the world --- p.19 / Chapter 1.8 --- Wetlands in Hong Kong --- p.19 / Chapter 1.8.1 --- Mai Po Inner Deep Bay Ramsar Site --- p.19 / Chapter 1.8.2 --- Wetland conservation in Hong Kong --- p.21 / Chapter 1.9 --- "Successful cases and constraints on wetland restoration, creation and conservation" --- p.22 / Chapter 1.9.1 --- The Ramsar Convention and wetland conservation --- p.22 / Chapter 1.9.2 --- Constraints in wetland restoration and creation --- p.32 / Chapter 1.9.3 --- Cases of wetland restoration and creation --- p.32 / Chapter 1.9.3.1 --- Restoring the habitat of endangered bird in southern California --- p.33 / Chapter 1.9.3.2 --- Creating tidal wetlands in San Diego Bay --- p.33 / Chapter 1.9.4 --- Constraints on wetland restoration and creation in Hong Kong --- p.33 / Chapter 1.9.4.1 --- Small scaled projects --- p.33 / Chapter 1.9.4.2 --- Lack of long-term management --- p.34 / Chapter 1.9.4.3 --- Lack of clear goals and objectives --- p.34 / Chapter 1.10 --- "Objectives, significance and outline of the present study" --- p.35 / Chapter 1.10.1 --- Research objectives --- p.35 / Chapter 1.10.2 --- Significance of the research --- p.35 / Chapter 1.10.3 --- Outlines of the thesis --- p.37 / Chapter Chapter 2 --- Growth performance of selected species of freshwater emergents under different levels of submergence in a natural wetland / Chapter 2.1 --- Introduction --- p.38 / Chapter 2.2 --- Materials and Methods --- p.41 / Chapter 2.2.1 --- Site description --- p.41 / Chapter 2.2.2 --- Planting --- p.42 / Chapter 2.2.3 --- Sampling --- p.42 / Chapter 2.2.3.1 --- Water --- p.43 / Chapter 2.2.3.2 --- Soil --- p.43 / Chapter 2.2.3.3 --- Plants --- p.43 / Chapter 2.2.4 --- Analysis --- p.43 / Chapter 2.2.4.1 --- Water --- p.43 / Chapter 2.2.4.2 --- Soil --- p.47 / Chapter 2.2.4.3 --- Plants --- p.47 / Chapter 2.2.5 --- Statistical analysis --- p.48 / Chapter 2.3 --- Results and Discussion --- p.48 / Chapter 2.3.1 --- Water quality in the trial plots at the Mai Po Marshes Nature Reserve --- p.48 / Chapter 2.3.2 --- Soil properties in plots under different levels of submergence at the Mai Po Marshes Nature Reserve --- p.53 / Chapter 2.3.3 --- Growth of freshwater emergents under different submergence levels --- p.59 / Chapter 2.3.3.1 --- Aboveground biomass --- p.59 / Chapter 2.3.3.2 --- Plant nutrient concentrations --- p.66 / Chapter 2.3.3.3 --- Plant nutrient yields --- p.67 / Chapter 2.4 --- Conclusions --- p.76 / Chapter Chapter 3 --- Growth performance of selected species of freshwater emergents under different levels of submergence in a created wetland / Chapter 3.1 --- Introduction --- p.78 / Chapter 3.2 --- Materials and Methods --- p.80 / Chapter 3.2.1 --- Site description --- p.80 / Chapter 3.2.2 --- Planting --- p.80 / Chapter 3.2.3 --- Sampling --- p.80 / Chapter 3.2.3.1 --- Water --- p.80 / Chapter 3.2.3.2 --- Soil --- p.84 / Chapter 3.2.3.3 --- Plants --- p.84 / Chapter 3.2.4 --- Analysis --- p.85 / Chapter 3.2.4.1 --- Water --- p.85 / Chapter 3.2.4.2 --- Soil --- p.86 / Chapter 3.2.4.3 --- Plants --- p.86 / Chapter 3.2.5 --- Statistical analysis --- p.87 / Chapter 3.3 --- Results and Discussion --- p.87 / Chapter 3.3.1 --- Water quality in the freshwater marshes at the Hong Kong Wetland Park --- p.87 / Chapter 3.3.2 --- Soil properties in the freshwater marshes under different levels of submergence at the Hong Kong Wetland Park --- p.92 / Chapter 3.3.3 --- Growth of freshwater emergents under different submergence levels --- p.100 / Chapter 3.3.3.1 --- Aboveground biomass --- p.100 / Chapter 3.3.3.2 --- Plant nutrient concentrations --- p.105 / Chapter 3.3.3.3 --- Plant nutrient yields --- p.109 / Chapter 3.4 --- Conclusions --- p.112 / Chapter Chapter 4 --- Growth performance of selected species of freshwater emergents under different levels of submergence and soil types in a greenhouse pot experiment / Chapter 4.1 --- Introduction --- p.114 / Chapter 4.2 --- Materials and Methods --- p.115 / Chapter 4.2.1 --- Experimental setup --- p.115 / Chapter 4.2.2 --- Harvesting --- p.117 / Chapter 4.2.3 --- Tissue analysis --- p.117 / Chapter 4.2.4 --- Statistical analysis --- p.117 / Chapter 4.3 --- Results and Discussion --- p.118 / Chapter 4.3.1 --- Aboveground biomass --- p.118 / Chapter 4.3.2 --- Plant nutrient concentrations --- p.128 / Chapter 4.3.3 --- Plant nutrient yields --- p.134 / Chapter 4.4 --- Conclusions --- p.140 / Chapter Chapter 5 --- General Conclusions / Chapter 5.1 --- Summary and implications of major findings --- p.142 / Chapter 5.2 --- Limitations of the study --- p.144 / Chapter 5.3 --- Further investigations --- p.145 / References --- p.148

本研究選取香港十二個淡水濕地，在二零零九年六月至二零一零年六月間調查其環境特性、蝌蚪及其相關的捕食者的種類和數量，以瞭解重要的環境因素如何影響蝌蚪在淡水濕地的多樣性及數量。三種蝌蚪（澤蛙、斑腿泛樹蛙及沼蛙）被選為研究對象，比較蝌蚪面對不同捕食者（中國鬥魚、食蚊魚、日本真龍虱及偉蜓科稚蟲）的外觀及行為反應，以瞭解蝌蚪的分佈與其面對捕食者的反應的關係，及調查捕食者的捕食效率。 / 在十二個淡水濕地的調查記錄了十一種兩棲類、十六種淡水魚類、三十一種蜻蜓（二十四種差翅亞目及七種束翅亞目）、四種鞘翅目及三種半翅目。沼蛙蝌蚪分佈最廣，出現在永久性及季節性濕地。斑腿泛樹蛙蝌蚪傾向出現於沒有捕食者的季節性濕地，澤蛙則傾向出現在沒有捕食者但水文週期較長的濕地。食蚊魚及狹腹灰蜻是數量最多及分佈最廣的淡水魚類和蜻蜓品種。 / 環境特性對蝌蚪在濕地的種類及數量的影響大於捕食者。水文週期與濕地的環境特性及捕食者種類關連，是最具影響力的環境因素。蝌蚪的多樣性於季節性濕地最高，而蜻蜓的多樣性則與水文週期長度成正相關。其他環境特性如基質，水位及植被覆蓋率對個別蝌蚪品種的數量有影響。 / 澤蛙、斑腿泛樹蛙及沼蛙能夠分辨不同種類的捕食者，並對魚類和無脊椎捕食者作出不同的外觀及行為反應。與無脊椎捕食者並存時，斑腿泛樹蛙蝌蚪在身體與尾部的交接處發展出較大而明顯的白斑，發展出較大尾部的蝌蚪的生長速度比對照組慢。與捕食者並存時，斑腿泛樹蛙及沼蛙蝌蚪的尾部顏色改變。斑腿泛樹蛙蝌蚪的游泳速度與身體形態相關，澤蛙及沼蛙蝌蚪則與體型大小相關。當面對捕食者時，三種蝌蚪均減少活動時間，游泳距離及速度。對比面對魚類時，在無脊椎捕食者之下，沼蛙蝌蚪的低活躍程度的維持時間較長。蝌蚪面對捕食者的反應的多樣性和蝌蚪與捕食者的相遇機率成正相關。 / 在田野調查中，發現魚類對蝌蚪數量的影響比蜻蜓稚蟲大，而鞘翅目及半翅目的數量則與蝌蚪數量沒有關連，由此推斷後兩者非蝌蚪的主要捕食者。中國鬥魚是最具效率的蝌蚪捕食者，相比之下食蚊魚雖捕食較少數量的蝌蚪，但憑其捕食習慣及野外數量之多足以導致蝌蚪種群數量下降。蜻蜓稚蟲也是具效率的蝌蚪捕食者，但因為蜻蜓稚蟲的羽化時間與兩棲類的繁殖時間同步（即稚蟲離開水體而蝌蚪進入水體時間基本重疊），總體上對蝌蚪構成較低的捕食風險。 / Environmental characteristics, larval amphibian assemblages and associated predators in twelve freshwater wetlands in Hong Kong were investigated from June 2009 to June 2010, in order to identify the key environmental characteristic(s) affecting the richness and abundance of tadpoles in freshwater wetlands in Hong Kong. Predator induced changes in morphology and behavior of three tadpole species (Fejervarya limnocharis, Polypedates megacephalus and Rana guentheri) were examined under the presence of Paradise Fish (Macropodus opercularis), Mosquito Fish (Gambusia affinis), Cybister and dragonfly naiads (Aeshnid) in order to investigate predator inducible defense(s) in local tadpoles and its relation to tadpoles’ distribution and effectiveness of local predators. / Fauna assemblages in 12 freshwater wetlands included 11 amphibian, 16 fish, 31 odonate (24 Anisoptera and 7 Zygoptera), four coleopteran and three hemipteran species. R. guentheri was the most widespread species and occupied both permanent and temporary wetlands. P. megacephalus were most commonly found in temporary wetlands without predators and F. limnocharis were common in wetlands with longer hydroperiod but without predators. Mosquito fish and Orthetrum sabina sabina were the most abundant and widespread fish and dragonfly species, respectively. / Abundance and occurrence of individual tadpole species were more attributable to environmental characteristics than to predators. Wetland hydroperiod was the most influential factor that correlated with environmental characteristics and occurrence of predator species. Larval amphibian richness was highest in temporary wetlands while dragonfly richness increased with habitat permanence. Other environmental characteristics such as substrate types, water depth and vegetation coverage also affected abundance of individual amphibian species. / Three tadpole species were capable of recognizing predators and exhibiting differential inducible changes when exposed to invertebrate and fish predators. P. megacephalus exhibited a large and prominent white spot at the body-tail intersection in the presence of invertebrate predators, and exhibited a growth cost in maintaining an enlarged tail. Tail coloration changed in P. megacephalus and R. guentheri in the presence of predators. Burst swimming performance was associated with body shape in P. megacephalus and to body size in R. guentheri and F. limnocharis. All three tadpole species showed a reduction in active time, travel distance and swimming speed in the presence of predators. R. guentheri reduced activity level for a longer time period after sensing invertebrate predation cues than after sensing fish cues. The variations in plasticity of predator-induced traits increased with predator encounter rate. / Fish caused a greater impact on tadpole abundance than dragonflies in field study, while coleopterans and hemipterans were probably not the major predators of tadpoles as no negative correlation with tadpoles were found. Efficiency of predation varied among fish species. The Paradise Fish was an efficient predator of tadpoles. Mosquito fish consumed fewer tadpoles and yet could cause a significant decline in tadpole populations by its foraging behavior and abundance in local freshwater wetlands. Dragonflies were efficient predator of tadpoles, however, the predation risk to tadpoles could be alleviated by synchronized timing of naiad emergence and amphibian breeding, along with predator-induced defenses of the tadpoles. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Wong, Chuk Kwan. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references (leaves 199-215). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts also in Chinese. / Abstracts --- p.i / Acknowledgements --- p.vii / of Contents --- p.ix / List of Tables --- p.xii / List of Figures --- p.xv / List of Plates --- p.xvii / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Wetlands --- p.1 / Chapter 1.1.1 --- Definition --- p.1 / Chapter 1.1.2 --- Wetland functions --- p.2 / Chapter 1.1.3 --- Hydrology and hydroperiod --- p.3 / Chapter 1.1.4 --- Predation and inducible defenses --- p.5 / Chapter 1.1.5 --- Predictions on inducible defenses --- p.7 / Chapter 1.2 --- Hong Kong Situations --- p.9 / Chapter 1.2.1 --- Climates in Hong Kong --- p.9 / Chapter 1.2.2 --- Amphibians diversity and habitats --- p.11 / Chapter 1.2.3 --- Habitat loss in Hong Kong and neighboring regions --- p.12 / Chapter 1.2.4 --- Wetland conservation policy in Hong Kong --- p.14 / Chapter 1.3 --- Knowledge Gap and Significance --- p.17 / Chapter 1.4 --- Objectives --- p.19 / Chapter 1.5 --- Thesis Layout --- p.19 / Chapter Chapter 2 --- Assemblages of larval amphibians and associated predators in freshwater wetlands in Hong Kong --- p.21 / Chapter 2.1 --- Introduction --- p.21 / Chapter 2.2 --- Materials and Methods --- p.24 / Chapter 2.2.1 --- Study sites --- p.24 / Chapter 2.2.1.1 --- Fauna survey --- p.24 / Chapter 2.2.1.2 --- Hydroperiod estimation --- p.29 / Chapter 2.2.1.3 --- Environmental characteristics --- p.31 / Chapter 2.2.1.4 --- Water quality --- p.31 / Chapter 2.2.2 --- Data analysis --- p.33 / Chapter 2.2.2.1 --- Multivariate analysis --- p.33 / Chapter 2.2.2.2 --- Data transformation --- p.34 / Chapter 2.3 --- Results --- p.39 / Chapter 2.3.1 --- Site characteristics --- p.39 / Chapter 2.3.1.1 --- Environmental characteristics --- p.39 / Chapter 2.3.1.2 --- Seasonal variation in water quality and wetness score --- p.43 / Chapter 2.3.1.3 --- Seasonal variation in water quality in four wetland types --- p.46 / Chapter 2.3.2 --- Species assemblages in local wetlands --- p.47 / Chapter 2.3.2.1 --- Tadpoles --- p.48 / Chapter 2.3.2.2 --- Dragonflies --- p.53 / Chapter 2.3.2.3 --- Damselflies --- p.53 / Chapter 2.3.2.4 --- Freshwater fish --- p.54 / Chapter 2.3.2.5 --- Coleopterans and hemipterans --- p.54 / Chapter 2.3.2.6 --- Seasonal variations in species assemblages --- p.55 / Chapter 2.3.3 --- Biodiversity of study sites --- p.58 / Chapter 2.3.3.1 --- Species richness in study sites --- p.58 / Chapter 2.3.3.2 --- Species abundance in study sites --- p.63 / Chapter 2.3.4 --- Multivariate analysis --- p.64 / Chapter 2.3.4.1 --- Global approach --- p.64 / Chapter 2.3.4.2 --- Independent approach --- p.76 / Chapter 2.3.4.3 --- Predator approach --- p.81 / Chapter 2.3.5 --- Hydroperiod and faunal assemblages --- p.92 / Chapter 2.3.5.1 --- Effect of hydroperiod on wetland diversity --- p.92 / Chapter 2.3.5.2 --- Effects of hydroperiod on faunal groups --- p.94 / Chapter 2.3.5.3 --- Effects of hydroperiod on species composition --- p.96 / Chapter 2.3.5.4 --- Comparison with other explanatory variables --- p.98 / Chapter 2.3.6 --- Hydroperiod, environmental characteristics and predation --- p.98 / Chapter 2.3.6.1 --- Effects of hydroperiod on environmental characteristics --- p.98 / Chapter 2.3.6.2 --- Effects of environmental characteristics on tadpoles --- p.99 / Chapter 2.3.6.3 --- Effects of predation on tadpoles --- p.99 / Chapter 2.3.6.4 --- Relative importance of environmental characteristics and predation --- p.100 / Chapter 2.3.7 --- Tadpole traits, wetland permanence and predation pressure --- p.100 / Chapter 2.4 --- Discussion --- p.104 / Chapter 2.5 --- Conclusions --- p.112 / Chapter Chapter 3 --- Predator-induced plasticity in tadpoles and its effect on survivorship under the presence of different groups of predator --- p.113 / Chapter 3.1 --- Introduction --- p.113 / Chapter 3.2 --- Materials and Methods --- p.117 / Chapter 3.2.1 --- Egg collection --- p.117 / Chapter 3.2.1 --- Predator collection --- p.118 / Chapter 3.2.2 --- Experimental design --- p.119 / Chapter 3.2.2.1 --- Predator induced plasticity in tadpoles --- p.119 / Chapter 3.2.2.2 --- Predation experiment --- p.126 / Chapter 3.2.3 --- Data analysis --- p.128 / Chapter 3.3 --- Results --- p.130 / Chapter 3.3.1 --- Morphological responses --- p.131 / Chapter 3.3.2 --- Tail coloration --- p.135 / Chapter 3.3.3 --- Burst swimming performance --- p.144 / Chapter 3.3.4 --- Life history --- p.149 / Chapter 3.3.5 --- Activity test --- p.153 / Chapter 3.3.5.1 --- Predator effects on activity level of Paddy Frog tadpoles --- p.153 / Chapter 3.3.5.2 --- Predator effects on activity level of Brown Tree Frog tadpoles --- p.157 / Chapter 3.3.5.3 --- Predator effects on activity level of Guenther’s Frog tadpoles --- p.160 / Chapter 3.3.6 --- Predation experiment --- p.164 / Chapter 3.4 --- Discussion --- p.174 / Chapter 3.4.1 --- Inducible changes in Paddy Frog tadpoles --- p.174 / Chapter 3.4.2 --- Inducible changes in Brown Tree Frog tadpoles --- p.175 / Chapter 3.4.3 --- Inducible response to rarely encountered fish --- p.178 / Chapter 3.4.4 --- Inducible changes in Guenther’s Frog tadpoles --- p.179 / Chapter 3.4.5 --- Effect of inducible defenses on tadpole survival --- p.180 / Chapter 3.4.6 --- Predator inducible changes and hydroperiod gradient --- p.181 / Chapter 3.4.7 --- Predator strength --- p.183 / Chapter 3.4.8 --- Importance of predation on tadpole assemblages --- p.185 / Chapter 3.5 --- Conclusions --- p.186 / Chapter Chapter 4 --- General Conclusions --- p.187 / Chapter 4.1 --- Summary --- p.187 / Chapter 4.2 --- Applications --- p.189 / Chapter 4.2.1 --- Mitigation wetlands --- p.189 / Chapter 4.2.1.1 --- Design --- p.189 / Chapter 4.2.1.2 --- Placement --- p.192 / Chapter 4.2.1.3 --- Management practices --- p.192 / Chapter 4.2.1.4 --- Natural model of temporary wetland --- p.194 / Chapter 4.2.2 --- Wetland conservation --- p.195 / Chapter 4.3 --- Further studies --- p.197 / References --- p.199 / Appendices --- p.216

Thesis (M. Phil. (Environmental Law and Management) -- University of Limpopo, 2010 / According to the Ramsar Convention of 1971, Wetlands are areas of marshes, firm, peatlands or waterlogged. They are either natural or artificial. They have water that is static or flowing, fresh, brackish or salty and include areas of marine water with the depth, which at low tides does not exceed six meters. Wetlands are regarded as important ecological components of the natural environment because of their richness and ability to support life. Wetlands essentially catch, clean and preserve any water. They are able to reduce the severity of drought and floods by regulating a stream flow. They also control erosion and provide habitat for many different plant and animal species. Wetlands also serve as valuable source of water, fish and grazing for livestock. They are important nesting grounds for birds. Wetland resources are also known to be of socio-economic importance because they provide materials for furniture and craft’s work Ga-Riba wetlands are very important for the community of Ga –Riba because they provide them with food such as fish and birds. Some of the community members make baskets, hats and mats using wetlands grass. They also make pottery using clay from the wetlands. During winter the wetlands are used as areas where traditional initiation for Ga-Riba girls is perfomed. Some people own fields within the wetlands on which they cultivate vegetables, maize and other crops. They also use wetland as grazing areas for their domestic animals such as cattle and goats. The Ga-Riba wetlands are being invaded by one of the alien plant called Populus alba L (Poplar). This type of alien plant, like other alien plants disturbs the ecological stability of the wetlands. Findings of the tests conducted on soil and water indicated that Poplars are changing the nature of the soil and the water of the wetlands. Vegetation survey showed that, wetlands had less vegetation than they were supposed to. With regard to legal instruments to control the invasion of wetlands by alien plants, findings showed that there are insuffient legal instruments which can be utilized.

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This thesis examines the relationship between the underlying ecological values of wetlands and the economic values they produce. The importance of the roles that wetlands play is now well recognised yet losses continue at a global level. It is argued that one cause of wetland loss is a lack of awareness of the values of these systems due to inadequate information of the nexus between ecological functions and economic values. For example, the off-site, indirect benefits provided by wetlands have largely been ignored. This has led to an undervaluation of these ecosystems. The integration of ecological and economic values requires incorporating differing types of information and systems of value derived from differing disciplines with differing paradigms. To understand the differing disciplinary perspectives the thesis explores the ecological functions of wetlands and the economic goods and services that they provide. The functions and benefits of wetlands are linked at the ecological-economic interface. A consensus on the definition of ecological value could not be discerned within the discipline of ecology. Thus, a definition and index of ecological value is developed to demonstrate the attributes of coastal and wetland systems that provide for instrumental human benefits. These attributes include productivity, the ability to provide habitats for dependent species and the diversity of species and organisation they support. However, ecological information is not presently available to operationalise the index. The ability of economic techniques to capture this ecological value is then investigated. Three approaches for assessing non-market values (direct linkage models, revealed preference and stated preference models) are reviewed with respect to their ability to capture ecological value. An alternative biophysical approach, namely energy analysis, is also considered. The review suggests that it may be possible to measure ecological value using the contingent valuation method. The role of information in preference formation and willingness to pay bids is then investigated along with a number of other issues that need to be resolved before using the contingent valuation method. The wetlands of the case study area, Moreton Bay, Australia exhibit both ecological and economic values. The wetlands contribute approximately one-third of primary productivity in the Bay, provide habitat for a wide range of dependent species (including internationally recognised migratory wader birds) and have a diverse fauna with a relatively large number of endemic species. Economic values of the wetlands include both direct and indirect use values (for example, fishing, recreation, water quality improvements and storm buffering) and non-use values. Non-use values include the value in preserving the environment for future generations (bequest value) and the existence of vulnerable animals such as turtles and dugongs, which one may never expect to see. If consumers are willing to pay to preserve these animals, this is also a valid economic value. The economic technique of contingent valuation is tested to determine if it is possible to capture ecological value by providing respondents, selected by random sample, to a survey with the relevant information. A case study is undertaken in Moreton Bay to determine respondents' willingness to pay to improve water quality and hence protect the wetlands. To test the effects of differing types information, four different versions of the survey were sent to four groups of 500 respondents. Case A provided no extra information so it could be used as a control. Case B included information about the ecological values of the wetlands of Moreton Bay. Case C provided information about the economic use values of the wetlands in the Bay including direct and indirect use. Case D provided information about the non-use values of endangered species resident in the Bay that are dependent on the wetlands. The results indicate that the provision of different types of information influences willingness to pay. However, willingness to pay when provided with ecological information is not significantly different from willingness to pay when provided with other information. As it was not possible from the research undertaken to state that the contingent valuation method can capture ecological value, an alternative approach is proposed to link ecological and economic values. It is argued that ecologists and economists need to develop common aims and scales of assessment. Further, communication between the two disciplines can be enhanced through the use of agreed indicator terms. Through an iterative approach it should then be possible to understand the linkages between changes in indicators of ecosystem values and indicators of economic value.

Landfills are a major potential source of groundwater and surface-water contamination. The compounds that can leach from landfilled materials include dissolved organic matter, inorganic macrocomponents, heavy metals, and xebobiotic organic compounds. Landfill surface-water runoff poses a threat to the environment due to high mobility, but has not been rigorously characterized with regards to common pollutants found in landfills. It is well documented that constructed wetlands can serve as an effective treatment option for many pollutants found in landfills. The Napanee Landfill has constructed a wetland in order to treat surface-water runoff coming off the landfill. The objectives of this study were to: 1) characterize the water chemistry of surface-water runoff for an inactive landfill; 2) evaluate the treatment potential for the constructed wetland system at the Napanee Landfill; and, 3) recommend design, maintenance, and operative improvements to enhance effluent water quality. The analysis of the landfill surface-water runoff entering the Napanee Landfill constructed wetland included the pollutants nitrate, ammonia, sulphate, phosphorus, and chloride. The median inflow and outflow concentrations for all of the observed pollutants did not exceed Canadian federal or provincial water quality guidelines. There were sampling days where ammonia, phosphorus, and chloride exceeded guidelines at the inflow and days where ammonia and chloride exceeded guidelines at the outflow. The only pollutant that saw a statistically significant decrease in concentrations was sulphate, with a change of 38% from the inflow to the outflow. Other changes of note were nitrate and phosphorus concentrations increasing by 50% and 23% respectively from the inflow to the outflow. There are a variety of improvements that can be made to the Napanee Landfill constructed wetland that would increase the treatment efficiency of ammonia. Incorporating a vertical-flow wetland would increase available surface area for nitrifying bacteria growth and would provide more oxygen for nitrification processes; both would increase the potential for significant ammonia treatment. Overall, the concentrations of the pollutants found in the surface-water runoff coming off of the Napanee Landfill constructed wetland did not pose a significant threat to the environment at the time of sampling and treatment processes were only successful in reducing sulphate pollutant concentrations.