Coastal habitats provide crucial nursery habitat for predatory fishes, but they are in decline worldwide, impacting economically important fisheries. Habitat restoration can simultaneously mitigate the effects of habitat loss and benefit predators (e.g., sportfish), although this relationship is understudied. Here, the response of juvenile sportfish to oyster reef and living shoreline restoration is compared to controls in the Indian River Lagoon, Florida prior to and following restoration for up to three years through examination of community (diversity, assemblage), population (abundance), biometric (size, body condition), ontogenetic, and trophic (gut contents, stable isotopes) dynamics. Stable isotopes were used to quantify dietary history, beyond the temporary record of gut content, using carbon (δ13C) and nitrogen (δ15N). This study found juvenile sportfish abundance and richness was higher at restored reefs compared to natural and degraded reefs and was comparable between stabilized and natural living shorelines. Biomass was higher at oyster reefs compared to living shorelines, which was likely driven by an ontogenetic shift of larger mangrove snapper Lutjanus griseus toward oyster habitat. Snappers and prey at live reefs were carbon (δ13C) enriched, with a smaller isotopic niche area compared to dead reefs, while restored reefs were intermediate and contracted over time. Therefore, sportfish at higher quality reefs likely exhibit greater site fidelity, particularly among less-mobile juveniles. Moreover, stabilized shorelines can achieve trophic equivalence to natural shorelines, as shown through their similar isotopic signatures and niche area. These responses were best predicted by benthic habitat (e.g., oyster density), prey abundances, and site location, demonstrating the connection between habitat quality and setting to provide prey that support sportfish populations. This study validates the benefits of habitat restoration to economically important fisheries, by augmenting various attributes of juvenile sportfish life history, which can improve their survival and recruitment into the adult population, and thus extend restoration outcomes.

No description available.

An improved dynamic electrothermal model for the Earth Radiation Budget Experiment (ERBE) total, nonscanning channels is formulated. This model is then used to accurately simulate two types of dynamic solar observation: the solar calibration and the so-called pitchover maneuver. Using a second model, the nonscanner active cavity radiometer (ACR) thermal noise is studied. This study reveals that radiative emission and scattering by the surrounding parts of the nonscanner cavity are acceptably small. The dynamic electrothermal model is also used to compute the ACR instrument transfer function. Accurate in-flight measurement of this transfer function is shown to depend on the energy distribution over the frequency spectrum of the radiation input function. A new array-type field-of-view (FOV) limiter, whose geometry controls the input function, is proposed for in-flight calibration of an ACR and other types of radiometers. Finally, the point spread function (PSF) of the ERBE and the Clouds and Earth's Radiant Energy System (CERES) scanning radiometers is computed. This PSF is useful in characterizing the channel optics. It also has potential use for recovering the distribution of the radiative flux coming from the Earth by its deconvolution with satellite measurements. / Ph. D.

Recent satellite measurements have found the range of solar radiation flux at the mean Earth-Sun distance to be from 1365 to 1372 W/m², or 1368 W/m² to within ±0.5 percent. This regularity is considered sufficient to permit the use of solar radiation as a source of energy for inflight calibration of radiometers designed to detect electromagnetic radiation in the solar spectrum. But direct viewing of the Sun would provide a flux considerably greater than the operating range of radiometers designed to observe typical Earth scenes. Therefore an attenuator is required. The Earth Radiation Budget Experiment (ERBE) radiometers, operational since 1984, relied on a mirror attenuator mosaic (MAM) to attenuate the solar energy. The ERBE MAM is an array of 105 tightly packed concave spherical mirrors with a black mask covering the surface between the hemispherical cavities and partially covering the cavities themselves. In principle, the reflection of solar energy by the MAM was anticipated to be independent of the solar incidence direction. Unfortunately, flight data revealed a variation with a solar incidence angle of as much as 20 percent for flux arriving at the detector during solar calibration. An improvement of the ERBE MAM design, suppression of the black mask, and reduction of the surface area of the spherical mirrors, has been achieved for the Clouds and the Earth's Radiant Energy System (CERES) radiometers, which will be operational sometime in the late-1990's. The topic of this thesis is the creation of a thermal-radiative model, based on the Monte-Carlo ray-trace method, to characterize the performance of the CERES MAM. The radiative analysis suggests that the current CERES MAM design is still somewhat less than optimal. The desired specifications are that the fraction of solar energy reflected by the MAM to the radiometer aperture be independent of the solar vector, and that the distribution of this reflected energy be uniform across the entire surface area of the radiometer aperture. The work reported here establishes that these specifications can be met by a simple reorientation of the MAM diffuser plate. / Master of Science

Terrestrial organic matter (TOM) constitutes an important source of energy in many aquatic environments (streams, lakes, wetlands). This is the first study to examine the role of TOM in food webs of the rocky intertidal zone. We compared the consumption of red alder leaves (Alnus rubra) to common marine sources of drifting detritus along the southern Oregon coast (Nereocystis luetkeana, Phyllospadix spp., and Fucus gardneri). We used short term (hours to days) and long term (months) feeding experiments to compare the rate of consumption among each plant species during the Spring and Fall of 2014 and 2015. In addition, we quantified the amount of TOM in beach wrack and in the drift of two streams that flowed directly to the rocky intertidal zone. We also measured the food quality of each plant species (C:N and polyphenolic concentrations). On average, the two small streams in this study transported 1,113.6 kg AFDM/m3 of TOM per day during Fall leaf abscission to the rocky intertidal zone. Also, the biomass of terrestrial leaves in beach wrack varied from negligible (2.1 g AFDM) to the dominant source of detritus (60.7 g AFDM) depending on if it was the dominant riparian plant growing along the edges of the shore. Consistent with previous research, N. luetkeana was a high quality food (C:N = 15:1; polyphenolics = 418 mg/ml), whereas F. gardneri (C:N = 22:1; polyphenolics = 8098 mg/ml) was more recalcitrant. Phyllospadix spp. was puzzling because it had low concentrations of polyphenolics (800 mg/ml) but was not consumed. Alnus rubra had a high concentration of structural compounds (C:N = 33:1) and intermediate levels of polyphenolics (3,415 mg/ml after leaching). Both short term and long term experiments showed that the rates of consumption of Spring-shed, green leaves and freshly fallen brown leaves of A. rubra were intermediate between N. luetkeana and the less palatable marine species (F. gardneri and Phyllospadix spp.). Thus, A. rubra was eaten by common intertidal consumers and may constitute an important source of energy between brief inputs of more nutritious marine resources (e.g. N. luetkeana).

<p>Elucidating the mechanisms structuring communities has been a challenge for community ecology since its beginnings. One theory argues that assembly rules structure communities by means of deterministic mechanisms arising from biological interactions. Another view maintains that patterns seen in community composition and species abundance result from stochastic processes such as migration and extinction. The dilemma has yet not been resolved unambiguously. The main issue is that communities shaped by deterministic mechanisms can produce stochastic patterns via priority effects. The main goal of this study was to determine whether assembly rules structure communities. My strategy was to minimize priority effects by controlling timing of colonization. To do this I used a null community by combining communities of 17 rock pools. This null community was later divided among experimental communities. I conducted three experiments: (1) Experimental communities were exposed to the same external conditions. (2) Communities were exposed to different environments, disturbance, dispersal and habitat heterogeneity. (3) Replicated null communities were connected to allow inter-replicate dispersal. After 4 months, communities (experiment 1) formed alternative states, suggesting the lack of assembly rules control in community structure. The second experiment showed that adding factors results in more alternative states. The increasing number of alternative states among replicate communities indicates that diversified environment and migration are needed to reproduce qualitative patterns observed in nature. The last experiment (3) showed that patterns observed among connected replicate communities resemble patterns that emerged in the presence of biological interactions in unconnected communities. Similarity of patterns between connected and unconnected groups of communities suggest that local biological interactions can be sufficient to structure communities to a considerable degree. Nevertheless, the regional processes appear necessary in their role of supplying species for local communities.</p> / Doctor of Philosophy (PhD)

<p>Aquatic vegetation in the pristine coastal marshes of eastern Georgian Bay (GB) provides critical spawning and foraging habitat for fish species, with complex habitat supporting the greatest diversity. These wetlands are threatened by a changing water level regime and forecasted lower water levels. To monitor and conserve these wetlands, we must understand how they function and respond to this stressor. The overall goals of this thesis are to determine the impact of declining water levels on both wetland fish habitat and the fish community as well as identify the spatial scale of habitat utilization by fishes.</p> <p>We first delineate all coastal wetlands in eastern GB, identifying 3771 wetlands that provide habitat for Great Lakes fishes. Using satellite imagery, we develop an object-based classification method to classify four types of wetland vegetation. Since submerged aquatic vegetation (SAV) is not visible from satellite imagery in GB, we develop a model to predict potential area of this important habitat. The model suggests that the response of SAV to declining water levels depends on wetland geomorphology, but generally, the area of SAV decreases. To assess the response of fish habitat coverage and structure to sustained low-water levels, we classify vegetation in images collected in 2002 and 2008. The result is increasingly homogeneous habitat, a net loss of fish habitat and a decrease in fish species richness. Finally, mark-recapture and radio-tracking are used to evaluate fish movement among closely situated wetlands. Results suggest that the current distance used to group and protect small wetlands provincially (750 m), likely protects most resident fish species, but does not cover movement patterns of a top predator. This research will advance our scientific understanding of freshwater coastal ecosystems and aid in the creation of conservation strategies to mitigate future threats from declining water levels.</p> / Doctor of Philosophy (PhD)

<p>Coastal wetlands are hydrologically connected to their watershed and the lake. Water levels in Georgian Bay have been at a sustained low for thirteen years and thus connectivity of wetlands to the lake is being threatened as water levels decline. Decreased connectivity has likely caused changes in ecological and chemical characteristics. Future climate change models predict further water declines and potentially increasing the number of wetlands that will be hydrologically disconnected. The over-arching goal of this thesis is to investigate the role of connectivity between the lake and coastal marshes in eastern Georgian Bay on the amount of potential fish habitat, water chemistry and larval amphibian habitat.</p> <p>Bathymetric information is needed in order to estimate fish habitat and two approaches were utilized in order to collect these data. A site-specific method completed in 2009 used an intensive field survey in seven wetlands to create a digital elevation model and calculated the amount of fish habitat at 10 cm increments. A second, regional method, selected 103 sites by using a stratified random sample in 18 quaternary watersheds. In both methods, changes in water levels between 173 and 176 m asl resulted in the most drastic loss of habitat. Approximately 24% of the current fish habitat has already been lost due to low water levels.</p> <p>Water chemistry in coastal marshes is influenced by hydrologic connection. In the summers of 2010 and 2011, 35 coastal marshes were sampled, 17 of which had been impounded and disconnected by a beaver dam. Beaver-impounded marshes resulted in significantly lower pH, conductivity, dissolved oxygen and sulphate concentrations, but had significantly higher soluble reactive phosphors concentrations. These conditions are indicative of the lack of connection and reduced mixing with lake water. This altered habitat was shown to support breeding area for 7 species of amphibians, the most common being green frogs and the least common being American Toads and chorus frogs.</p> / Master of Science (MSc)

International Telemetering Conference Proceedings / October 22-25, 2001 / Riviera Hotel and Convention Center, Las Vegas, Nevada / This paper presents the results of a feasibility study undertaken by the University of Salzburg (Austria), investigating the autonomous acquisition of environmental data in a global network. A suggested application which is used as the basis of this paper is a volcano monitoring system which would be able to track the activity of a volcano and act as a disaster warning system. The background Volcano observation data required for such a system is covered, before discussing the concepts for sensor data acquisition, storage and processing. A final analysis is then presented of the opportunities for the transmission by packet radio (both terrestrial and satellite).

<p>This thesis concerns the predator-prey interactions of three raptor species in a Swedish arctic community: the gyrfalcon (<i>Falco rusticolus</i>), the rough-legged buzzard (<i>Buteo lagopus</i>) and the golden eagle (<i>Aquila chrysaetos</i>).</p><p>The gyrfalcon behaved like a highly specialised ptarmigan (<i>Lagopus spp.</i>) predator. Gyrfalcon’s functional response to ptarmigan was close to density independent, and ptarmigan remained the dominating prey even in areas with the lowest ptarmigan density. The gyrfalcon did not respond functionally to microtine rodents (i.e. lemmings and voles) and it was clear that the gyrfalcon did not use microtines as an alternative prey category to ptarmigan. As the gyrfalcons did not switch to any alternative prey when ptarmigan was scarce, their reproductive success seemed to be directly dependent on the amount of ptarmigan available in the breeding territories. Of the two ptarmigan species in the study area, rock ptarmigan (<i>L. mutus</i>) dominated gyrfalcon’s diet. Locally, the proportion of rock ptarmigan in gyrfalcons’ diets showed a positive relationship to the expected availability of rock ptarmigan in the breeding territories, indicating a density dependent utilisation. </p><p>The rough-legged buzzard behaved like a highly specialised microtine rodent predator and Norwegian lemming (<i>Lemmus lemmus</i>) was its preferred microtine species. The buzzards showed a type 2 functional response to lemmings. Surprisingly though, they also had a type 3 functional response to grey-sided voles (<i>Clethrionomus rufocanus</i>). We present an optimal diet model where a central place forager, during good food conditions, benefits from partial prey preference, which renders separate functional responses to each prey category. We discuss how the double functional responses of the buzzard affect the population dynamics of sympatric vole species, on both temporal and spatial scales.</p><p>The golden eagle behaved like a generalist predator, and it preyed on all major prey categories in the study area: microtines, ptarmigan, mountain hare, (<i>Lepus timidus</i>) and reindeer (<i>Rangifer tarandus</i>). It seemed to respond functionally to microtine rodent fluctuations with an increased consumption of lemmings during a peak year in the microtine rodent cycle. The golden eagle showed a numerical response to its main prey, the ptarmigan. </p><p>Ptarmigan, microtine rodents and hares seemed to have synchronized population fluctuations in the study area. Such synchronized population fluctuations are believed to be generated by predation. Although the three raptors are the main predators of their community, their predation patterns fail to explain the observed prey population dynamics in the study area. </p>