Anthropogenic activities are often considered to be the main sources of mercury (Hg) found in aquatic systems. The aim of this study was to reconstruct the historic input of Hg to a large lake (Lake Ekoln) situated downstream the City of Uppsala using a dated sediment core. The main objective was to reveal general long-term (millennia-scale) trend in mercury loadings to the lake assess to what extent the lake has received an increase input of mercury during the last century from atmospheric inputs or local sources (mining activities, hospital effluents, industries or agricultural activities). Sediment samples were analyzed with X-ray fluorescence spectroscopy for measurements of lead and phosphorous (used as a proxy for atmospheric inputs and effluent water, respectively). Total Hg was analyzed using a mercury analyzer. My results indicate high Hg concentrations in sediment of Lake Ekoln during the last three centuries. Hg concentrations was not correlated to atmospheric derived metals (Pb) or effluent water derived nutrients (P) and only weakly correlated to the organic matter content of the sediment. Highest concentrations was found during a period around 1850 and in the last few years. The weak correlation with Pb suggest that the Hg is entering the lake from other sources than atmospheric inputs. The most likely local sources are argued to be mining activities (including fossil fuel burning during the production of iron) or Uppsala university hospital situated upstream of Lake Ekoln. However, there is a large uncertainty regarding the importance of these historical Hg sources for the lake.

Excessive sedimentation is a major stressor to ecosystem health in freshwater systems globally. Benthic macroinvertebrates are excellent bioindicators of ecosystem health because they have a range of environmental tolerances and are typically associated with certain substrate types. This study tested the hypothesis that sedimentation is a driver of benthic macroinvertebrate communities by determining their responses to increased deposited sediment levels in the Northern Great Plains using both experimental and survey approaches. In both approaches, the effects of deposited sediment were isolated, the responses of specific indicator invertebrates were characterized and finally, indices that commonly respond to deposited sediment were analyzed for their sensitivity. At the community level, the overall multivariate redundancy model was not significant and deposited sediment accounted for only 0.2% of the total variation in species composition in the river survey. Indicator species analysis identified taxa that were associated with sediment impairment classes in both studies. Index sensitivities indicated that Percent Swimmers responded to sediment and can potentially be used as an index of deposited sediment in this region, however this index was not sensitive to sediment in the landscape-scale survey. Although individual taxa that responded to sediment deposition may be used as bioindicators of sediment impairment in further studies, the relatively small effect of sediment at the community level and on univariate composition metrics suggests benthic macroinvertebrate communities are adapted to deposited sediment in the Northern Great Plains.

Soil microbes influence the global carbon cycle via their role in the decomposition and formation of soil organic matter. Thus, rates of ecosystem processes such as primary production, soil respiration, and pedogenesis are sensitive to changes in the aggregate functional traits of the entire microbial community. To predict the magnitude and direction of microbial feedbacks on climate change, it is necessary to identify the physiological, ecological, and evolutionary mechanisms that underlie microbes’ responses to altered temperature and rainfall. Therefore, I examined microbial community composition and function in relation to manipulations of resource availability and precipitation in two contrasting ecosystems: a tropical rainforest at La Selva Biological Station, Costa Rica, and a semi-arid grassland in central Texas. I conducted a leaf litter decomposition experiment at La Selva to identify the physiological constraints on microbial allocation to extracellular enzymes, which degrade organic matter. I found strong evidence that microbial enzyme production is decoupled from foliar stoichiometry, consistent with weak links between leaf litter nutrients and decomposition rates at the pan-tropical scale. Next, to examine whether ecological trade-offs within microbial communities may drive shifts in carbon cycling at local spatial scales, I quantified changes in soil fungal and bacterial community composition in response to an in situ precipitation exclusion experiment I established at La Selva. Although drought-induced shifts in community structure were small, large increases in biomass-specific respiration rates were observed under dry conditions. These findings suggest that physiological adjustments to drought may constitute an important feedback on climate change in wet tropical forests. Finally, I focused on microbial community responses to climate change within a meta-community framework, using a reciprocal transplant experiment to investigate how dispersal shapes bacterial community structure along a natural rainfall gradient in central Texas. I found that soils from the wet end of the precipitation gradient exhibited more plastic functional responses to altered water availability. However, soil bacterial community composition was resistant to changes in rainfall and dispersal, preventing functional acclimatization to precipitation regime. Together, the results of these experiments emphasize the potential for physiological plasticity or microevolutionary shifts within microbial populations to drive ecosystem carbon cycling under climate change. / text

Aim: This series of studies assessed the influence that digenean parasites exert on a host population beyond the initial cost of infection. It aimed to address the discrepancy between the exclusion of parasites from most ecological studies, and their functional importance within the wider free-living community. It also assessed methodologies that utilise the diversity of the parasite community as well as the phenotypic effects of parasitism, as potential tools for ecology and palaeoecology. Results: From 2004-2007, in excess of 53,000 snails were dissected during the course of these studies. Making it one of the most detailed parasitological studies undertaken on a single host parasite interaction in this field. Community studies - Parasite diversity was found to be influenced by local scale abiotic, as well as large scale environmental patterns. Parasite diversity correlates with the distribution of definitive avian hosts, which in turn correlates with intertidal benthic communities. These correlations provide an effective methodology for monitoring ecosystem health. Behavioural studies - A critical assessment of parasite mediated behavioural change revealed the indirect cost of gigantism in the host population to be a side effect, and that differences in behaviours were often a result of size rather than infection. Growth/Morphometric studies - Gigantism was revealed as both infection and environment driven. Finally, morphometric analysis revealed conchiometric markers that provide tools for reconstructing past environments and infection prevalence. Main conclusions: The functional importance of digenean parasitism within the intermediate host snail Hydrobia ulvae, extends far beyond the individual. Digeneans directly and indirectly manipulate the host population, in turn affecting wider community structure. Environmental, abiotic and biotic factors can leave observable imprints on the infected and uninfected host population. Such markers can provide tools and methodologies for furthering our understanding of both extinct and extant host-parasite populations.

Small wetlands are often ignored in inventory studies; consequently they are less protected and therefore more vulnerable. Moreover, previous research indicates the importance of small wetlands as they can provide important ecosystem services to human kind. The Environmental Protection Agency of Sweden has carried out a national wetland inventory, however they have applied a limited area, which consequently excludes smaller wetlands. This study aims to make an inventory of the excluded wetlands smaller than 10 hectares in Laholms municipality, Halland. In this inventory study I have applied GIS as a method by comparing different map layers, such as aerial photos, land cover data and Google Earth. Furthermore, the study aims to investigate the ecosystem services provided by the located wetlands in the study area and discuss how this exclusion could affect the services. The results of the inventory indicate that 745 wetlands are missing in the Environmental Protection Agency inventory, which correspond to 12 percent of the total wetlands in Laholms municipality. The results also indicate that 99,1 percent of the missing wetlands are mire and 0,9 percent are riparian wetlands. In the literature study I found that mire provides ecosystem services such as carbon storage, material such as peat, and unique habitats for biodiversity. Riparian wetlands provide ecosystem services such as unique habitats for biodiversity, improving the quality of the water, reduce fertilization and provide recreational values. Moreover, both type of wetlands are also important to the wetland mosaic in order to maintain proliferation and the local hydrological systems.  Additionally, small wetlands are especially important to invertebrates and amphibians. Though, if the small wetlands in Laholms municipality continue to be ignored then the benefits of the ecosystem services mentioned above are likely to be reduced and limited.

As urban municipalities grow, local governments are tasked with balancing the economic, political, social, and environmental needs of their communities in an effort to develop sustainable urban planning policies. This thesis uses the City of Red Deer as a single case study to examine a municipality's vision of urban sustainability within the context of ecological planning and protection. Concepts of ecosystem goods and services, biodiversity protection, and enhanced water quality were reviewed with research on riparian management, landscape level planning, and ecological protection to provide a lens for reviewing Red Deer's land protection framework. Ultimately, this research provides policy recommendations for development setbacks and land preservation strategies which could greatly contribute to the long-term sustainability of the community. Although this research focuses on the City of Red Deer, the policy recommendations can be applied to similar municipalities and landscapes across the nation.

No description available.

Pterocarpus officinalis dominated forests are a rare ecosystem, found only in fifteen locations in Puerto Rico, all of which are adjacent to the coast and at risk from sea level rise, as well as nutrient pollution, upstream hydrological modifications, and deforestation. All forests of this type that were located further inland were destroyed by agricultural development during the early decades of the 1900’s, in particular to grow sugarcane. Prior to this study, there was little information on the diversity of organisms that live in these forests. The central objective of this proposal was to examine the diversity and species composition of three Pterocarpus forests in Puerto Rico located near Humacao, Patillas, and Dorado, and to compare and contrast diversity among the three forests, and identify possible differences caused by human impacts or natural factors. The data was collected through surveys and sampling at each location. Transect surveys, plots, pitfall traps, insect traps and audio recordings were carried out to identify organisms including birds, mammals, amphibians and reptiles, insects, mollusks, invertebrates, plants and fungi. The Dorado Pterocarpus forest is the most rich and diverse in terms of organisms and has the highest amount of native and endemic species, while the Humacao Pterocarpus forest is the least rich and diverse. Yet conversely, the Dorado forest is the smallest forest, covering only 2.4 ha, while Humacao is the largest, with an area of 150 ha that comprises 63% of the total Pterocarpus coverage in Puerto Rico. The most obvious factor influencing richness and diversity among the forests is the adjacent land cover and history of the sites. Inflow and water sources may also be a factor that alters richness and diversity. This knowledge will assist in the appropriate management of this rare resource in the context of ongoing sea level rise, climate change, nutrient pollution, upstream hydrological modifications, and deforestation. Coastal managers need this information to manage and protect these valuable and rare ecosystems.

No description available.

The purpose of this thesis is to investigate if the application of the ecosystem services concept can provide decision makers and stakeholders with additional relevant information for decisions regarding establishing of aquaculture on a local level, using the Lake Storsjön as a case study. In order to provide this knowledge, three different tasks are carried out within this thesis: the identification of the main ecosystem services provided by Lake Storsjön, the understanding of ecosystem services that will be affected by the expansion of aquaculture and the identification of the services that will be used for a possible expansion of the aquaculture sector. The CICES methodology (Common International Classification of Ecosystem Services) is used to identify the ecosystem services provided by Lake Storsjön. The understanding of the affected ecosystem services is carried out with the use of a Delphi-inspired approach. The identification of the services required for the establishment of aquaculture is driven by a cross-reference matrix. Lake Storsjön provides thirty-nine out of the fifty-nine ecosystem services included in the CICES. About half of these will be effected by environmental impacts connected to operations of ecosystem management required by aquaculture expansion, mostly with a low or medium degree of impact. An increase in the implementation of aquaculture might cause detrimental trade-offs with these ecosystem services: “Wild animals”, “Genetic materials from all biota“, “Disease control”, “Maintaining nursery populations and habitats” and “Filtration/dilution/sequestration/storage/accumulation by ecosystem”. An expansion of the aquaculture sector requires seven of the ecosystem services provided by Lake Storsjön. The vital services for this process are: “Surface water for non-drinking purposes”, “Filtration/dilution/sequestration/storage/accumulation by ecosystem” and “Chemical condition of freshwater”. These services have to be safeguarded and maintained in order to guarantee adequate conditions for an expansion of this sector. At the same time the expansion of aquaculture supports the service “Animals from in situ aquaculture”. The benefits connected to the implementation of aquaculture shall be economically assessed and compared to the actual economic value delivered by the other ecosystem services in order to further understand the positives and negatives outcomes of aquaculture expansion in an ecosystem services perspective. This is considered to be a relevant step for strategic and decision making processes concerning aquaculture expansion in Lake Storsjön. In addition to the economic perspective, it seems that the most relevant factor when discussing planning and development processes towards ecosystem services is the importance of not overshooting the resilience ability of the ecosystem in order to ensure the accessibility of the services to future generations. This belief is recommended to be applied to Lake Storsjön in order to guarantee a conscious expansion of the aquaculture sector on a social, economic and environmental level.