Microbial mats have played an important role in the carbon (C) and nutrient cycles since the Archean Eon and modern mats are important contributors to the biogeochemistry of intertidal wetlands. Microbial mats are flat assemblages of microbes that are currently found in many unvegetated habitats globally. Intertidal salt pans are a common habitat for microbial mats, however little is known about the distribution of microbial mats within the intertidal landscape. Understanding the spatial distribution of microbial mats is critical to developing quantitative estimates of the impacts of microbial mats on their ecosystems. We photographically measured the presence and density of microbial mats within 1 m2 quadrats across a landscape scale (~1000 Ha) on the Gulf Coast of Florida. The wide variety of metabolic processes that are found within microbial mats makes the net biogeochemical impacts of the microbial mats highly variable as well. To explore the biogeochemistry associated with microbial mats, we measured a suite of soil attributes under microbial mats and compared those measurements to nearby soils without microbial mats. We found that microbial mats are found on soils with biogeochemical attributes that are significantly different than soils without microbial mats. Soil organic matter, nitrate concentration, and soil temperature significantly increased in soils under microbial mats; pH was significantly lower in soils under microbial mats. Also notable was although the concentration of soil organic matter was higher, the bioavailability of that organic matter was significantly lower. Microbial mat presence is correlated with geomorphic variables such as proximal boundaries, as well as neighboring vegetation and other microbial mats.

The Swedish Nuclear Fuel and Waste Management Company, SKB, is planning to construct a deep geological repository for spent nuclear fuel in Forsmark, Sweden. Leakage of groundwater into the repository during the construction and operational phases might cause a groundwater drawdown that in turn may affect the hydrological conditions in sensitive habitats in the area. The sensitive habitats in question are wetlands, home to several protected species. SKB has planned to take mitigation measures in the case variations of the surface-water elevation are identified for the concerned wetlands. The mitigations measures consists in infiltrating water in the ground in the direct vicinity to the wetland to create a higher groundwater pressure that then will propagate to the surface-water. This study describes the modelling of a pilot-study of such a measure and aims at serving as one of the background materials for the planning and design of the pilot study. The aims of the pilot study are to show that the surface-water level in a wetland can be controlled and to gain knowledge and experiences regarding artificial groundwater recharge for this purpose. The pilot study would take place before the construction of the repository so the undisturbed case is considered. The results show that an infiltration facility can control the surface-water level in a wetland. It is also shown that an infiltration rate of 0.5 L/s is enough to manipulate the surface-water level in the undisturbed condition.

The purpose of this research is the design of a green infrastructure that allows a regional conservation area to revalue the Ventanilla wetlands to promote ecotourism through spaces for the conservation of natural resources, turning it into a tourist attraction. The proposal considers design and construction criteria with adequate technology, biodegradable, and sustainable materials where environmental impact is minimized in this context. The collection of information through field visits and the use of different software for the topographic survey. Results show that the infrastructure design proposed was validated by a survey of potential users of the place, with 75% of the interviewees agreeing with the design proposal that allows interaction and harmony with nature, giving it a landscape value, generating local, national, and international visitors. The value is in the ecosystem services that the landscape provides to the city due to the design and construction criteria with adequate technology, biodegradable, and sustainable materials minimizing the environmental impact and promoting the cultural exchange, preservation, and ecological awareness wetland. / Revisión por pares

Phalaris arundinacea L. is an aggressive species that can dominate wetlands by producing monotypic stands that suppress native vegetation. In this study invasion windows were created for native species in monotypic stands of P. arundinacea with either fire or herbicide. Three native species groups, herbaceous plants, herbaceous seeds, and woody shrubs, were planted into plots burned or treated with herbicide in the early spring. Fire did not create an effective invasion window for native species; there was no difference in P. arundinacea root and shoot biomass or cover between burned and control plots (p ≥ 0.998). Herbicide treatment created an invasion window for native species by reducing P. arundinacea root and shoot biomass for two growing seasons, but that invasion window was fast closing by the end of the second growing season because P. arundinacea shoot biomass had nearly reached the shoot biomass levels in the control plots (p = 0.053). Transplant mortality, frost, and animal herbivory prevented the herbaceous species and woody seedlings from becoming fully established in the plots treated with herbicide during the first year of the experiment. Transplanted monocots had a greater survival than dicots. By the second growing season the herbaceous group had the greatest mean areal cover (5%), compared to the woody seedlings (3%) and seed group (0%). Long-term monitoring of the plots will determine whether the herbaceous transplants will compete effectively with P. arundinacea and whether the woody species will survive, shade the P. arundinacea, and accelerate forest succession.

The Great Salt Lake (GSL) wetlands account for ~75% of all Utah wetlands and provide not only critical habitat for millions of migratory birds, but also provide valuable ecosystem functions and services as well as economic benefits to Utahns. However, these wetlands are facing an aggressive invader, Phragmites australis, that has spreading across the GSL wetlands and replacing native wetland habitats. Wetland managers have spent countless resources and time trying to control the spread of P. australis and restore GSL wetlands. However, we do not fully understand how these wetlands functions and services are being altered with this habitat homogenization because functional data for our wetland species have not been well documented. This lack of knowledge may hinder wetland restoration efforts. To create baseline functional data for the GSL wetland species and better understand how the spread of P. australis might be affecting the overall health of the system, I measured eight individual ecosystem functions for seven dominant habitat types found across the GSL wetlands. I compared these individual functions across habitat types as well as created two different multifunctionality indices using an averaging and a thresholds approach. With these comparisons, I was able to determine the distinct functional strengths of different wetland habitat types and their overall functional abilities. I found that functional abilities varied greatly by habitat type and that not one single habitat could support every function even at the lowest threshold measured. I found that Typha latifolia, Schoenoplectus acutus, and P. australis, had the highest multifunctional values. However, I also found that some habitats offered unique functions, such as Salicornia rubra and playa, and that these functions were lacking in other habitats, including the most multifunctional habitats. These findings suggest that maintaining habitat heterogeneity will be critical in ensuring a fully functioning wetland system that can provide a multitude of ecosystems services that benefit both humans and wildlife. The findings of this study will supply wetland managers with a better understanding of the functional strengths of different wetland habitats. This data will aid in ongoing restoration efforts by enabling managers to target certain functions and create more efficient and effective management plans.

Magister Philosophiae - MPhil / Microplastics (MPs) are an emerging micro-pollutant that pose a threat to the ecological integrity of freshwater rivers and wetlands. Most previous work on MPs pollution has focused on marine environments. This study aimed to investigate the spatial distribution and abundance of MPs particles in the bed sediment of a freshwater coastal lake in the Zeekoevlei Nature Reserve, Cape Town, which is fed by rivers and stormwater outlets draining a heavily urbanized environment. The first objective was to characterize the spatial distribution of MPs across the lakebed environment, in relation to possible point and non-point sources of contamination.

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Aquatic habitats are closely linked to surrounding terrestrial environments via reciprocal subsidies. Much of the research on these subsidies has been focused on streams, while subsidies across aquatic-terrestrial boundaries of other aquatic systems, like temporary ponds, have received little attention. Temporary ponds are seasonally inundated aquatic habitats and patterns of energy transport across transient aquatic-terrestrial boundaries are not well understood. To address the lack of information regarding these cross-habitat subsidies, I quantified: 1) leaf litter inputs, 2) amphibian egg inputs, 3) terrestrial insect inputs, 4) amphibian metamorph emergence, and 5) aquatic insect emergence for eight temporary ponds. Terrestrial insect inputs to ponds represented substantial high-quality subsidies to ponds that are generally unaccounted for in similar studies. While larger ponds produced greater total fluxes to terrestrial habitats, smaller ponds were often more productive per unit area. Therefore, a mosaic of small ponds may produce greater or equivalent subsidies and may be of greater value to terrestrial food webs than a single large pond. Resource subsidies of energy and nutrients can be transported via physical forces or biotic processes, such as animal migration or emigration. I quantified net nutrient fluxes associated with amphibian migrations across aquatic-terrestrial boundaries of eight temporary ponds in Illinois. I measured carbon (C), nitrogen (N), and phosphorus (P) subsidies from forests to ponds, in the form of eggs, and the reciprocal subsidies from ponds to forests via juvenile emigration. Juvenile emergence biomass did not resemble egg biomass, as not all species bred successfully in each pond, resulting in variability in the magnitude of nutrient fluxes both across ponds and species. The forest was not always the recipient system of net nutrient fluxes. Hydroperiod, trophic interactions, and species composition explained some dynamics of N and P subsidies. Most studies have focused on the magnitude of cross-boundary fluxes, but the impact of a subsidy is mediated by the size of the flux as well as the quality and relative abundance of similar resources in the recipient habitat. Long-chain polyunsaturated fatty acids (LC-PUFAs) are necessary for proper physiological function, are unevenly distributed across the landscape, and animals differ greatly in their ability to synthesize them de novo. This creates the potential for limitation and increases their possible importance as a subsidy. I examined LC-PUFA tissue concentration and export in eight species of emerging amphibian metamorphs across eight temporary ponds in a wetland complex. I found that tissue concentrations and export of LC-PUFAs varied across species, but were generally within the ranges of several freshwater fish and aquatic insects. Anurans exported higher amounts of LC-PUFAs than salamanders, largely due to the higher emergence biomass of anurans. Further, I explored fatty acid profiles and immune function of wolf spiders in wetland and upland habitats. Wetland spiders had higher tissue levels of aquatic-derived LC-PUFAs and elevated immune function compared to upland spiders. These patterns suggest aquatically derived nutrients, such as LC-PUFAs, may benefit organisms exploiting freshwater habitats.

Arrow et al. (1993) issued guidelines for contingent valuation, one of which was the recommendation that valuation questions include a ‘no-answer’ option such as ‘I prefer not to vote (PNV)’ in addition to the typical ‘yes’ and ‘no’ options. However, they did not give further guidelines on what to do with such responses, and there are various opinions in the literature. The objective of this thesis was to identify factors that affect the probability of a respondent choosing the PNV option in stated preference surveys. This thesis identified a positive relationship between offered bid for the proposed environmental project and the probability of respondents choosing PNV and a negative relationship between perceived consequentiality of the survey and the probability of respondents choosing PNV. From the findings, this thesis suggests possible solutions to reduce the frequency of such responses in order to increase accuracy of welfare estimates and cost efficiency.

Interactions between animal populations and their environment form the foundation of wildlife management, and provision of resources that enhance fitness produce effectual management. Hunting is a selective force that shapes behavior and other adaptations of harvested species and may subsequently impact diel habitat use. Moreover, linking habitat use to biological outcomes, such as survival, is needed to evidence habitat suitability because of equivocal relations among population density, habitat correlations, or energy availability to population dynamics. The mallard (Anas platyrhynchos) is among the most coveted and harvested waterfowl in North America and is a migratory species of ecological, economic, and social importance. The Mississippi Alluvial Valley (MAV) is an ancestral and continentally important wintering area for North American mallards despite significant anthropogenic wetland transformation. Through targeted objectives and consequence of soil and water conservation, financial assistance programs have expanded waterfowl habitat on private lands in Mississippi. I radiomarked 265 female mallards and tracked their diel habitat use in winters 2010-2015 to evaluate objectives related to their wintering ecology in the MAV of Mississippi. Specifically, I investigated whether waterfowl hunting influenced use of some habitats during hunting season, the effectiveness of financial assistance programs in providing habitat, and habitat suitability through habitat specific survival rates. Females made greatest use of forested and emergent wetlands diurnally and emergent wetlands and flooded cropland at night. Results suggested that mallards did not avoid flooded cropland or emergent wetlands diurnally during hunting season, but conclusions were complicated by significant use of inviolate sanctuaries. Mallards used numerous incentivized conservation program wetlands, but use was less than public and privately managed wetlands. Among conservation programs, those with large enrollment and a focus on restoration (i.e., Wetlands Reserve Program) were most used by mallards. Apparent survival was independent of diurnal habitat use suggesting that mallards use of wetland complexes leads to their winter survival. Restoration of forested wetlands should be a management focus and easement programs provide such inroads on private lands. Public wetlands are an important source of habitat and inviolate sanctuary should be considered where waterfowl hunting is a predominate activity.