Waters Edge began with the inspiration to be closer to water and progressed into exploring architecture within the inhabitation of the riverscape through the vehicle of an urban kayak station. A 1:1 scaled kayak was constructed to materialize the conceptual research and provide a means to understand the relationship between built form and water. The necessity of each line and material component in the kayak construction manifested itself into the making of the urban kayak station. Further research into the St. Johns rowing regatta and boat making enhanced the social aspect of revitalizing Winnipeg’s river culture. A series of architectural models and drawings were constructed to explore the conceptualizations of the research and multiple iterations of the project emerged. The research concludes with further exploration into the way we inhabit the riverscape.

Waters Edge began with the inspiration to be closer to water and progressed into exploring architecture within the inhabitation of the riverscape through the vehicle of an urban kayak station. A 1:1 scaled kayak was constructed to materialize the conceptual research and provide a means to understand the relationship between built form and water. The necessity of each line and material component in the kayak construction manifested itself into the making of the urban kayak station. Further research into the St. Johns rowing regatta and boat making enhanced the social aspect of revitalizing Winnipeg’s river culture. A series of architectural models and drawings were constructed to explore the conceptualizations of the research and multiple iterations of the project emerged. The research concludes with further exploration into the way we inhabit the riverscape.

Understanding the relationship between heterogeneity, biodiversity and ecosystem function is an active focus of ecological research that has direct applications to the formulation of sustainable, science-based, watershed conservation plans. Here, I applied ecological theory on heterogeneity to the expansion of North American beaver to test hypotheses about physical habitat and fish biodiversity at a riverscape scale. To test these hypotheses (Chapter 4), I first addressed two methodological issues (Chapter 2, 3). By evaluating three types of gear at three levels of effort in a randomized block design over 4 replicate days, I show that 10 minnow traps, 2 hoop nets and 20 m of electrofishing captured most fish species within a 30-m sampling area (Chapter 2). Multiple statistical measures provided similar information, therefore I used general indices (richness, diversity), ecological guilds (flow based), and select multivariate analyses (DCA) to summarize fish communities (Chapter 3). I used these methodological insights to test ecological hypotheses by collecting habitat and fish data at all beaver dams (n = 15) and select control sites (n = 9) in Fish Brook, a coastal watershed in northeastern Massachusetts. From these data, I gained six basic and applied insights. First, beaver dams were distributed throughout the stream network. Second, at a local scale, beaver dams created more habitat heterogeneity than control sites. Specifically, beaver dams created four types of habitat alterations based on upstream-downstream differences in stream width, depth, velocity, and substrate. Third, richness and diversity of fish species around beaver dams were linked to habitat heterogeneity. Fourth, the mechanisms by which beaver dams altered fish biodiversity were mediated through habitat changes at the beaver dam patch boundary. Upstream of the dam macrohabitat guilds occupied the lentic areas, while below dams, fluvial fish guilds used shallow, faster water. Fifth, fluvial species responded the most dramatically to these habitat changes. Finally, in a system depauperate of lotic habitat, fluvial habitats created below beaver dams provided an important refuge for native stream fish. These source areas can increase resiliency and maintaining them may be useful for sustainable watershed conservation plans in these types of systems.

Abstract This project describes the development of a river habitat map of the Big South Fork National River and Recreation Area (BISO NRRA) using GPS-based video mapping and image georeferencing techniques. The Big South Fork of the Cumberland River and major tributaries have been floated and mapped with GPS, sonar, and georeferenced under and above water video cameras. Video footage is interpreted for physical bedforms and compiled in an ArcGIS attribute table that can be queried for species specific habitat location. Underwater video mapping system (UVMS) bedform data includes river characteristic (pool, riffle, run), substrate (bedrock, fines/sand, gravel, cobble, and boulder), embeddedness, sonar depth, rugosity, and sinuosity. The Clear Fork River and New River (3rd order streams), White Oak Creek and North White Oak Creek (2nd order streams), and the Big South Fork of the Cumberland River, a 4th order stream are compared based on the EPA Qualitative Habitat Evaluation Index (QHEI). Relationships between bedform parameters are evident in UVMS data, and large boulder substrate was predicted with 67% accuracy based on sonar depth and river characteristic. The rugosity metric can indicate the location of other habitat characteristics, such as large woody debris and riverbed drop-offs. Embeddedness distribution was modeled using SAS based on UVMS data. The linear, quadratic, and non-linear models poorly fit the embeddedness distribution, with R-squared values of 0.37, 0.42, and 0.33 respectively. Traditional river habitat assessment methods vary in scale from stream length categorization based on satellite imagery and topographic maps (kilometer resolution), to aquatic microhabitat inventory by biologists (0.1 m resolution). Typically, reach scale (10 m resolution) and mesoscale (1 m resolution) studies are limited by accessibility and man-hours in the field. The underwater video mapping system (UVMS) allows for stream scale habitat quantification with mesoscale resolution. Kayak or canoe based UVMS can map river habitat inaccessible from land. Georeferenced river characteristic and substrate video can be evaluated by biologists in the lab, reducing time and labor required for field studies. One limitation of UVMS is that underwater bedform data is recorded only in the thalweg, the deepest continuous line along a watercourse.

Ever since its founding, Rome has been vulnerable to the swelling waters of its Tiber River. This river was so important to the city that it was a defining character in Rome’s history for over two thousand years. However, this river-city relationship would be suddenly severed in the late 19th century as Rome was declared the Italian capital. And, with the creation of the capital, came the creation of the river walls. While this new infrastructure safeguarded the city from future flooding, it razed the relationship between the city and its river. It lost its use as a commercial trade route, transportation system and leisure landscape, and before long the Tiber was forgotten. This thesis proposes a design intervention at Rome’s historic river-city site, the Porto di Ripetta. Once the physical and symbolic gateway to the city, the Ripetta is presently the most disconnected site along the Tiber River. Not only does the proposed project aim to synergistically unite a series of complex archaeological layers from antiquity to present-day, it also aspires to reconnect the city to its historical relationship with its river, introduce another layer within Rome’s transportation network, and expand the city’s cultural agenda along its underutilized continuous corridor. The introduction of river-based programme is logical when created within a series of design solutions that both recognize and address the temporal nature of the riverscape. Through in-depth historical analysis, this thesis examines the complexities of the Tiber River’s existence and analyzes its sociological, physical and political importance to the Eternal City. This understanding of the Tiber River’s unique qualities reveals tangible opportunities for new public spaces connected the potential of the Tiber as part of an expanded network of new public transportation, leisure landscapes, and cultural institutions.

AbstractThis project describes the development of a river habitat map of the Big South Fork National River and Recreation Area (BISO NRRA) using GPS-based video mapping and image georeferencing techniques. The Big South Fork of the Cumberland River and major tributaries have been floated and mapped with GPS, sonar, and georeferenced under and above water video cameras. Video footage is interpreted for physical bedforms and compiled in an ArcGIS attribute table that can be queried for species specific habitat location.Underwater video mapping system (UVMS) bedform data includes river characteristic (pool, riffle, run), substrate (bedrock, fines/sand, gravel, cobble, and boulder), embeddedness, sonar depth, rugosity, and sinuosity. The Clear Fork River and New River (3rd order streams), White Oak Creek and North White Oak Creek (2nd order streams), and the Big South Fork of the Cumberland River, a 4th order stream are compared based on the EPA Qualitative Habitat Evaluation Index (QHEI).Relationships between bedform parameters are evident in UVMS data, and large boulder substrate was predicted with 67% accuracy based on sonar depth and river characteristic. The rugosity metric can indicate the location of other habitat characteristics, such as large woody debris and riverbed drop-offs. Embeddedness distribution was modeled using SAS based on UVMS data. The linear, quadratic, and non-linear models poorly fit the embeddedness distribution, with R-squared values of 0.37, 0.42, and 0.33 respectively.Traditional river habitat assessment methods vary in scale from stream length categorization based on satellite imagery and topographic maps (kilometer resolution), to aquatic microhabitat inventory by biologists (0.1 m resolution). Typically, reach scale (10 m resolution) and mesoscale (1 m resolution) studies are limited by accessibility and man-hours in the field. The underwater video mapping system (UVMS) allows for stream scale habitat quantification with mesoscale resolution. Kayak or canoe based UVMS can map river habitat inaccessible from land. Georeferenced river characteristic and substrate video can be evaluated by biologists in the lab, reducing time and labor required for field studies. One limitation of UVMS is that underwater bedform data is recorded only in the thalweg, the deepest continuous line along a watercourse.

Ever since its founding, Rome has been vulnerable to the swelling waters of its Tiber River. This river was so important to the city that it was a defining character in Rome’s history for over two thousand years. However, this river-city relationship would be suddenly severed in the late 19th century as Rome was declared the Italian capital. And, with the creation of the capital, came the creation of the river walls. While this new infrastructure safeguarded the city from future flooding, it razed the relationship between the city and its river. It lost its use as a commercial trade route, transportation system and leisure landscape, and before long the Tiber was forgotten. This thesis proposes a design intervention at Rome’s historic river-city site, the Porto di Ripetta. Once the physical and symbolic gateway to the city, the Ripetta is presently the most disconnected site along the Tiber River. Not only does the proposed project aim to synergistically unite a series of complex archaeological layers from antiquity to present-day, it also aspires to reconnect the city to its historical relationship with its river, introduce another layer within Rome’s transportation network, and expand the city’s cultural agenda along its underutilized continuous corridor. The introduction of river-based programme is logical when created within a series of design solutions that both recognize and address the temporal nature of the riverscape. Through in-depth historical analysis, this thesis examines the complexities of the Tiber River’s existence and analyzes its sociological, physical and political importance to the Eternal City. This understanding of the Tiber River’s unique qualities reveals tangible opportunities for new public spaces connected the potential of the Tiber as part of an expanded network of new public transportation, leisure landscapes, and cultural institutions.

The impact of invasive predators on native prey may depend on the availability and distribution of invader-free refugia across landscapes, if predators create demographic ‘sink’ populations in invaded patches, giving rise to source-sink dynamics in prey populations. Propagule pressure of immigrants dispersing from refugia (or sources) may consequently drive persistence in sink habitat, affecting predator-prey co-existence across the landscape. I studied whether introduced brown (Salmo trutta) and rainbow trout (Oncorhynchus mykiss) create source-sink structuring in two native galaxiid fish species (Galaxias vulgaris and G. paucispondylus) in the rivers of the central South Island, New Zealand, and whether such dynamics affected the distributions of either species across river networks or “riverscapes”. Young-of-the-year (YOY) G. vulgaris recruitment was rare in trout-invaded streams and consistently high in trout-free streams. Thus, trout-free reaches appeared to act as sources in a river network, while the majority of the trout-invaded riverscape was a demographic sink (i.e., no local recruitment occurred). Surveys of YOY G. paucispondylus did not reveal trout-induced source-sink dynamics, although mesocosm predation experiments suggested both species were highly vulnerable to predation by large trout. Galaxias paucispondylus recruitment was highest in intermittently flowing streams that were marginal habitats for trout, suggesting indirect interactions between trout and habitat affect G. paucispondylus distribution. Network configuration of trout-free source populations affected the distribution of G. vulgaris, as galaxiids were excluded from small streams with high bed stability that were far from sources. The interaction between propagule pressure and habitat gradients in mediating effects of trout on G. vulgaris distributions indicates habitat characteristics affect predator-prey interactions in a spatially explicit manner. Furthermore, the outcome of predator-prey interactions should be able to be modelled using habitat data alone if habitat consistently mediates predator impacts. I developed a GIS-based spatial model to predict where trout would exclude G. vulgaris in river networks, based on stream size and distance to galaxiid source populations. The model was tested in three different riverscapes using fish occurrence patterns obtained from electrofishing surveys, and successfully predicted G. vulgaris exclusion by trout. This further demonstrates the importance of habitat configuration in driving interspecific interactions at the landscape scale. These findings suggest removing trout from small, stable tributaries to create new demographic sources could improve overall persistence of G. vulgaris across trout-invaded riverscapes. The galaxiid exclusion model should also be used to detect undiscovered trout-free source populations, and to aid in selecting streams for restoration of galaxiid populations through trout eradication.

The impact of invasive predators on native prey may depend on the availability and distribution of invader-free refugia across landscapes, if predators create demographic ‘sink’ populations in invaded patches, giving rise to source-sink dynamics in prey populations. Propagule pressure of immigrants dispersing from refugia (or sources) may consequently drive persistence in sink habitat, affecting predator-prey co-existence across the landscape. I studied whether introduced brown (Salmo trutta) and rainbow trout (Oncorhynchus mykiss) create source-sink structuring in two native galaxiid fish species (Galaxias vulgaris and G. paucispondylus) in the rivers of the central South Island, New Zealand, and whether such dynamics affected the distributions of either species across river networks or “riverscapes”. Young-of-the-year (YOY) G. vulgaris recruitment was rare in trout-invaded streams and consistently high in trout-free streams. Thus, trout-free reaches appeared to act as sources in a river network, while the majority of the trout-invaded riverscape was a demographic sink (i.e., no local recruitment occurred). Surveys of YOY G. paucispondylus did not reveal trout-induced source-sink dynamics, although mesocosm predation experiments suggested both species were highly vulnerable to predation by large trout. Galaxias paucispondylus recruitment was highest in intermittently flowing streams that were marginal habitats for trout, suggesting indirect interactions between trout and habitat affect G. paucispondylus distribution. Network configuration of trout-free source populations affected the distribution of G. vulgaris, as galaxiids were excluded from small streams with high bed stability that were far from sources. The interaction between propagule pressure and habitat gradients in mediating effects of trout on G. vulgaris distributions indicates habitat characteristics affect predator-prey interactions in a spatially explicit manner. Furthermore, the outcome of predator-prey interactions should be able to be modelled using habitat data alone if habitat consistently mediates predator impacts. I developed a GIS-based spatial model to predict where trout would exclude G. vulgaris in river networks, based on stream size and distance to galaxiid source populations. The model was tested in three different riverscapes using fish occurrence patterns obtained from electrofishing surveys, and successfully predicted G. vulgaris exclusion by trout. This further demonstrates the importance of habitat configuration in driving interspecific interactions at the landscape scale. These findings suggest removing trout from small, stable tributaries to create new demographic sources could improve overall persistence of G. vulgaris across trout-invaded riverscapes. The galaxiid exclusion model should also be used to detect undiscovered trout-free source populations, and to aid in selecting streams for restoration of galaxiid populations through trout eradication.

Les changements globaux provoquent une disparition accélérée des espèces endémiques. Il apparait crucial de quantifier les risques potentiels d’extinction en relation avec les changements climatiques liés à l’activité anthropique, et particulièrement pour les espèces dont l’aire de répartition est restreinte. Dans ce travail de thèse je me suis intéressé aux effets des changements globaux sur le complexe de la truite du Mexique qui vit dans le nord-ouest du Mexique. Ce complexe représente le groupe des salmonidés avec la distribution la plus méridionale au monde, avec seulement deux taxa décrits : la truite dorée mexicaine (Oncorhynchus chrysogaster) et la truite de San Pedro Mártir (O. mykiss nelsoni).En tant qu’espèce montagnarde d’altitude, ces salmonidés sont très vulnérables aux effets des changements globaux, et particulièrement au changement climatique et à l’introduction d’espèces exotiques pour l’aquaculture, comme la truite arc en ciel. Les objectifs généraux de cette thèse étaient de déterminer les relations entre les processus micro-évolutifs chez la truite mexicaine dorée, ainsi que la structure spatiale de leur habitat qui définissent les risques d’extinction engendrés par les changements globaux.Afin de répondre à ces questions, j’ai appliqué aux écosystèmes de rivières une approche de génétique du paysage intégrant différentes échelles spatiales à différents niveaux taxonomiques, ainsi j’ai appliqué des analyses de génétique des populations, des analyses de système d’information géographique et de modélisation de la distribution des espèces, ainsi que des simulations démo-génétiques.Initialement, les analyses de génétique des populations réalisées sur 11 loci microstallites nous ont permis de mettre en évidence une structure génétique spatialisée pour l’ensemble du complexe des truites mexicaines, ainsi qu’une introgression génétique chez la truite endémique. Ces résultats ont été confirmés par d’autres analyses utilisant un plus grand nombre de microsatellites et de marqueurs SNP. Une étude plus fine centrée sur O. chrysogaster et combinant simulations génétiques et distribution de l’espèce a permis de définir les caractéristiques des paysages de rivières comme les principaux déterminants de la structure génétique des populations natives, voire comme des barrières aux flux de gènes. Pour cette espèce, j’ai également généré une base de données de 9676 SNP grâce aux techniques de séquençage de nouvelles génération et mis en évidence une structure génétique cryptique chez O. chrysogaster. Une approche de génomique du paysage a révélé une influence significative des variables physiques des rivières sur la structuration génétique neutre et adaptative de la truite dorée mexicaine. / The combined effect of different threats has caused an accelerated loss of biodiversity in endemic species. Then, it is crucial to quantify potential extinction risks as consequence of global change related with human activities, especially in range restricted species. An example of that situation is represented by the native Mexican trout complex inhabiting the highlands of northwest Mexico and representing the group of salmonids with the southernmost distribution in the world, with the Mexican golden trout (Oncorhynchus chrysogaster) and the coastal nelson trout (O. mykiss nelsoni) as the only described species for this complex.However, as mountaintop species, these salmonids are highly vulnerable to global change effects, mainly by climate change and the introduction of the exotic rainbow trout for aquaculture purposes. The overall aim of this PhD project is to assess the possible relationships between microevolutionary processes of the Mexican golden trout, as well as the spatial structure of their habitat defining extinction risks derived by global change.To address those questions, a riverscape genetics approach was applied at different spatial scales and taxonomic levels including population genetics analyses based on neutral microsatellite markers and Next Generation Sequencing (NGS), G.I.S. (Geographic Information Systems; riverscape characterizations), species distribution modeling and demo-genetic simulations.Initially, population genetics analyses of 11 microsatellite loci revealed a spatial genetic structure for the entire Mexican trout complex as well as genetic introgression for native trout collected in aquaculture farm proximities, these results were corroborated by other using more microsatellite and SNPs markers. Moreover, focusing on O. chrysogaster, species distribution models and demogetic simulations defined riverscape as the main factor driving native population genetic structure, and as a boundary against exotic introgression. Additionally, 9,676 SNP’s were generated by NGS techniques defining a cryptic genetic structure for O. chrysogaster. Finally, landscape genomics approaches revealed a significant influence of riverscape factors on the neutral and adaptive genetic structure of the species.