Soil nitrogen availability to plants is a fundamental control on the structure and functioning of arctic tundra ecosystems. Despite recent evidence that biogeochemical and microbial dynamics during the non-growing season impact nitrogen availability to plants in tundra ecosystems, very little is known about soil microbial patterns and mechanisms for nutrient mobilization in the winter, spring and fall. In this dissertation I have examined the environmental and microbial controls on seasonal nitrogen mobilization in a widespread Canadian low arctic birch hummock tundra ecosystem. In particular, I have investigated the potential for increased winter snow depth and different above-ground vegetation-types to alter soil microbial community patterns and nutrient mobilization from organic matter into plant-available pools. First, I demonstrated that experimentally deepened winter snow altered soil microbial physiology during winter, defined as increased microbial carbon limitation to growth and activity. Second, I established that deepened snow enhanced spring nutrient mobilization during distinct environmental phases, producing large peaks in the soil microbial biomass and soil solution carbon, nitrogen and phosphorus during snow thaw. Third, I showed that laboratory predictions of early-spring air temperature freeze-thaw cycles promoting tundra soil nitrogen loss are not relevant, as the soil environment and soil biogeochemistry were relatively stable after snow melt and before plant growth began. Fourth, I demonstrated that microbial functional groups did not differ strongly under different tundra vegetation types, but higher quality shrub litter induced positive feedbacks on soil carbon availability and soil nitrogen mineralization in the late summer. Finally, I illustrated that annual patterns of tundra soil microbial community structure and composition were strongly linked to soil biogeochemistry and that significant shifts in fungal/bacterial ratios occur during snowmelt. This research suggests two broad conclusions: a) that soil microbial activity is responsive to changes in above-ground vegetation; and b) that seasonal changes in microbial community structure and microbial biochemistry are strongly correlated. Therefore, the synchronicity of microbial seasonal succession and plant species-specific timing of nitrogen uptake is a critical factor restricting the potential for ecosystem N losses at spring thaw and ultimately in supplying growth-limiting nutrients to plants in the following summer. / Thesis (Ph.D, Biology) -- Queen's University, 2009-09-25 23:29:53.103

This thesis undertakes a review of the Remedial Action Plans (RAPs) for the St. Lawrence River Area of Concern (AOC). As directed by Great Lakes Water Quality Agreement, RAPs are to take a systematic and comprehensive ecosystem approach to restoration, and ensure that the public is consulted about restoration activities. Through triangulation of three different research methods: twelve semi-structured interviews, observational research, and document analysis, this research explores how these two principles were incorporated into the St. Lawrence River AOC. This research draws from environmental management and governance literature in order to describe the implementation and decision-making frameworks of the RAP program. In theory an ecosystem approach is to be holistic and comprehensive in scope and application. In terms of the St. Lawrence River AOC, the holistic nature of the restoration process was hindered by the jurisdictional complexity of the region; Not only was there two federal governments, Canada and the United States, but the province of Ontario, state of New York, and the Mohawks of Akwesasne Nation. These jurisdictional divisions led to the eventual decision to separate the AOC into two RAPs at Massena, NY and Cornwall, ON. This division led to a divergence in impairment indicator identification and resultant restoration practices, timelines for RAP progress reports, availability of financial resources, and collective organization of restoration duties. The goal of each RAP is to eventually delist as an AOC. Through a review of the collective organization of the Cornwall RAP, it is best described as participatory and inclusive in terms of governance. There was representation and membership from government, industry, First Nations, and the public making the Cornwall RAP an example of solidarity in action. Because there has been a unification of visions through the RAP process, which is to have a clean and health St. Lawrence River, momentum has been generated to expand the ideals of the RAP to a broader St. Lawrence River collective. Lessons learned from this restoration process are constructive for cross-jurisdictional, multi-media restoration projects and serve to inform approaches to ecosystem restoration, planning, and management, especially that of the St. Lawrence River. / Thesis (Master, Environmental Studies) -- Queen's University, 2010-09-30 15:39:18.132

No description available.

Natural ecosystems are dynamic and complex, with many being threatened by human activity. However, humans can also be at the root of a solution to this problem by developing ecosystem engineering which can be used to design, construct, modify, upgrade, repair, remediate, and maintain ecosystems. The aim of this project was to improve virtual ecosystems that can be used to increase the knowledge base for ecological engineering by studying adaptability as a factor for the success of species. This was done by analysing adaptive species in a virtual ecosystem, a computer application with which various configurations can be designed and studied in a closed environment. The virtual ecosystems used in this project represent ecosystems in general rather than any specific ecosystem, and allow for repeatable test cases to be run so that ecosystem dynamics can be studied. Adaptability was defined as the ability of an individual to adjust to a short term environmental pressure according to two factors: the adaptation speed, which is how fast an individual can respond to a change in environment, and the adaptive capacity, which is a quantitative indicator of how much the individual is able to adapt. In this project, experiments were performed to determine the effects of adaptability when applied to one aspect of individuals in an ecosystem. From the results of the experiments it was seen that the adaptation speed value could affect the success of a producer species in an ecosystem both positively and negatively. It was also found that ecosystems with both a consumer and producer species could persist longer when adaptability was incorporated into the individuals of the consumer species.

<p>Two species of Chrysaora are described from the northern Benguela ecosystem: C. fulgida and C. africana. These species can be diagnosed by a combination of morphological features including lappet and tentacle number, shape of lappets, colouration patterns (alive), shape of the proximal portion of radial septa, gastrovascular pouch shape, point of attachment of gonads and the presence or absence of small raised nematocyst warts on the exumbrellar surface. Objective, quantitative statistical analyses coupled with molecular sequence data support the qualitative morphological dissimilarity observed, as these analyses unambiguously diagnose C. fulgida and C. africana as two distinct species. There is a strong superficial resemblance between the C. fulgida material described here and the preserved specimens of C. hysoscella examined at the Natural History Museum, London. Thorough investigation does however allow the separation of these two species. Morphological features found to be dissimilar were the proximal portion of the manubrium, gastrovascular pouch shape and the presence or absence of sperm sacs. Objective, quantitative statistical analyses support these findings. Nuclear sequence variation suggests considerable divergence between the two species but additional molecular work is needed.</p>

<p>Developing countries often hoard the largest number of species, but also experience very high poverty levels. This dissertation reviews the evidence of the performance common conservation interventions. I find that despite the billions of dollars channeled towards conservation efforts annually, there is still very limited evidence whether or not conservation policies work. The evidence has been limited to exceptional countries like Costa Rica and Thailand and outlines like deforestation, without considering ecosystem function and ecosystem services. Furthermore, I find that the conservation impact evaluation literature has currently not highlighted the channels through which conservation policies effect change and how the effectiveness varies with the baseline characteristics of the area. </p><p>This dissertation aims to address some of the gaps in current conservation literature. Focusing on Indonesia between 2000 and 2006, I evaluate the performance of protected areas in terms of stalling deforestation as well as providing a wide range of ecosystem services and benefits (Chapter 2). In Chapter 3 I examine the role of context in which protected areas operate and show significant heterogeneity in their performance. In Chapter 4 I develop a static spatially explicit model of household fuelwood extraction that allows me to predict the location and magnitude of spillovers when a protected area is introduced. I find that depending on the characteristics of the areas, it may be optimal for households to buy fuelwood than collect it.</p> / Dissertation

The Tamana Cave system in Trinidad is relatively unaffected by the environment outside of the cave walls, like most cave ecosystems. Since a very limited amount of light can enter the cave, bat movement controls the temperature cycle rather than the solar radiation that controls it in the surrounding forest. Similarly, the ecosystem cannot be sustained by energy from photosynthesis and so the main source of energy comes from the guano produced by the insectivorous bat species, N. tumidirostris. The frugivorous bat species, P. hastatus, also roosts inside of the cave, but the wetness of the top level of its guano prevents the guano from being suitable for cockroach consumption and therefore ends the flow of energy through the system. STELLA software was used to create a model consisting of three stacked logistic growth equations that demonstrate the ecosystem of Tamana cave. The model focuses on the population of insectivorous bats, on the guano that this species produces, and on the cockroach species, E. distanti. The model provides insight into the population dynamics and environmental processes at play in the cave, and is useful in predicting the behavior of the ecosystem. After running the model under a number of different scenarios, the graphs were used to visually display the effects of altering inputs in the system. These altered inputs represent hypothetical changes that could occur in a natural system such as a lowered intrinsic rate of increase bat population, an increase in initial bat population, or a decrease in the amount of guano that each cockroach needs to survive.

New Zealand is an isolated island nation and more than 95% of its commodities are imported by ship, making New Zealand particularly vulnerable to marine bioinvasion. Its marine biota and ecosystem are unique with numerous endemic organisms, and it is a biodiversity hotspot of global significance. The objective of this study was to integrate invasive theory with phylogeographic studies on a native ascidian. This study was motivated by the introduction of an invasive ascidian, Styela clava to New Zealand. To date, S. clava’s cytochrome oxidase I (COI) data indicate limited sharing of haplotypes between the ports of Lyttelton and Auckland, and areas within Hauraki Gulf. The connectivity between these disparate sites may be a consequence either of common overseas origins via international shipping or local vectoring within New Zealand by coastal shipping. In this thesis I have examined the phylogeographic relationships among populations of an endemic ascidian, Cnemidocarpa nisiotis, to attempt to gauge the likely role that local vectoring plays in the movement of ascidians and other species among New Zealand ports. This study also provides the first population genetic information on a native New Zealand ascidian An endemic New Zealand ascidian was chosen as the study species because the use of an endemic species excludes or at least reduces the possibility of external input from overseas sites con-founding any patterns observed in the data. Furthermore, by excluding external input, the pattern of genetic diversity observed in this species might enable us to determine if local shipping pathways are homogenising C. nisiotis populations. C. nisiotis individuals were collected inside and outside of ports and marinas around Haruaki Gulf, Wellington, Lyttelton, and Dunedin harbours. Each individual were dissected and morphologically identified. Morphological identification of C. nisiotis matched type specimen (Chapter 2). However, preliminary results with COI haplotype network revealed three lineages (A, B and C) and such was the level of differences among these lineages raised the question of the possibility of a cryptic species. This 3 hypothesis was further investigated with phylogenetic analysis using both COI and 18S ribosomal DNA sequence data. Phylogeographic analysis of C. nisiotis COI molecular data demonstrated no significant population genetic structure, with a single common haplotype shared between the North and South islands (Chapter 4). Sharing of haplotypes was also evident between harbours in the South Island and within sites where population samples from inside ports, marinas, and natural habitats were not significantly different from each other. The lack of difference between the North and South Island for this species was surprising given that it was believed to have limited dispersal ability in the absence of anthropogenic movement. However, C. nisiotis displays a star-like phylogeny indicative of a selective sweep, population bottleneck or founder event followed by a population range expansion, thus the lack of difference between islands may be a consequence of too little evolutionary time having passed since the populations shared a common origin for differentiation to have occurred.

A restored elk (Cervus elaphus) population in eastern Kentucky may be affecting ecosystem processes in a landscape composed of reclaimed grassland expanses and isolated forest remnants. Elk routinely select forested ridge-tops as resting and ruminating sites. These locations are characterized by sparse or absent leaf litter, trampled and diminished vegetation, large deposits of dung, and urine-saturated soils. In fall 2003, a series of fenced ungulate exclosures were constructed; 8 on highly disturbed forested ridge-tops and 8 on reclaimed grasslands. Soil analyses measured % moisture, pH, total nitrogen, total carbon, ammonium, nitrate, phosphorus, and major extractable cations in 0-10 cm and 10-20 cm cores. Litter depths and percentages of bare ground, vegetative cover, litter cover, and woody debris were measured. Sediment and water samples were collected monthly from sediment traps on reference and experimental ridge-tops. Studentfs t-tests were used to determine significance (p . 0.10) between treatments. Disturbed ridge-tops had higher soil ammonium (0.68 mg/kg, 10-20 cm) than reference sites (0.25 mg/kg) in spring 2004 and lower ammonium (0.72 mg/kg, 0-10 cm; 0.44 mg/kg, 10-20 cm) than reference sites (1.80 mg/kg, 0-10 cm; 0.94 mg/kg, 10-20 cm) in summer 2004. Total carbon was higher inside (67.57 g/kg, 0-10 cm) than outside (45.38 g/kg) of ridge-top exclosures in fall 2004. Soil moisture, litter depths, and vegetative cover were generally lower, while % bare ground was higher on disturbed ridge-tops. Sediment collected from traps averaged 2.21g/m2 inside exclosures, 2.86 g/m2 outside exclosures, and 0.39 g/m2 on reference ridge-tops. These data suggest that this reintroduced species is changing several attributes of the Cumberland Plateau landscape. The lack of a predator such as the gray wolf (Canis lupis) or cougar (Puma concolor) likely contributes to the development of habitual elk use of landscape features such as remnant ridge-top forests. Such concentrated use may create conditions for the colonization of certain plant species including rare natives and invasive exotics. Continued monitoring of high use areas is recommended so that managers can fully understand the long-term impact of the return of this large, gregarious herbivore, and that appropriate management actions can be developed to promote native biodiversity.

New markets for the conservation of so-called ecosystem services, like the ability of a wetland to mitigate floods, are emerging worldwide. According to environmental economists, these markets require some metric - ecological or otherwise - that names the relevant characteristics of the service to be traded as a commodity. But while this is often assumed to be a simple task of science, I argue that the environmental regulators, eco-entrepreneurs, and conservationists who actually design and implement metrics are not so easily brought into agreement. In “rolling-out” revamped metrics and protocols, regulators and their conservationist allies in one market in Oregon haven’t established the conditions for market success so much as they have constrained entrepreneurs. The solutions to ecosystem destruction 20 years ago - privatization, commodification, and commercialization - have become the obstacles which limit the market’s future viability. The moments when capitalists find themselves saying “let’s sell nature to save it” - or when states say it for them - can spell trouble for capitalists at the same time that they seem like their escape hatch. Still, the short-term and long-term effects of market design may differ; barriers to the market now may prove to be its success later.