The American beaver, the largest rodent of North America, is distributed in ponds, lakes, and streams from Alaska to northern Mexico. This semi-aquatic mammal is considered an ecosystem engineer because beavers modify the landscape by cutting trees and by creating dams and ponds that have important effects on the aquatic community structure, providing habitat for aquatic invertebrates, fish, and birds. The American beaver has played an important socioeconomic role in the history of North America due to beavers' fur value, which caused the near extirpation of this mammal at the beginning of the 1900s due to overharvest by early Europeans. Because of the highly specific habitat requirements of beavers, this mammal also suffers the effects of habitat loss in some areas where riparian ecosystems are now scarce. My objectives in this study were to assess how climatic and geological events affected the current distribution of the American beaver in North America, and how the management actions to restore and control beaver populations have affected the genetic structure and conservation of beaver populations. Specifically, I addressed four aspects of the management and conservation genetics of the beaver: 1) a literature review of the management of beavers in the past 100 years; 2) the development of novel microsatellite DNA markers to address the population genetic structure aspects of the study; 3) the use of these microsatellite DNA markers to assess genetic diversity of current populations of beavers and to detect past population bottlenecks; and 4) the use of two mitochondrial DNA genes to resolve the current phylogeography of the American beaver in order to better understand how historical factors have affected the beaver's current distribution and genetic structure in North America. The results from this study provide information of the effects that management actions and climatic events can have on the genetic structure of beavers. This information can be used by wildlife biologists, and land managers, to develop future strategies for management and conservation of the American beaver.

Comprendre de quelle façon les populations animales répondent aux conditions qui prévalent dans leur environnement revêt une grande importance. Les conditions climatiques et météorologiques sont une source importante de variabilité dans l'environnement et celles-ci ont des répercussions sur les espèces sauvages, en affectant leur physiologie, leur comportement et leurs ressources. Les ongulés alpins et nordiques font face à une succession annuelle de conditions environnementales favorables et défavorables, entraînant chez ceux-ci d'importants changements de masse saisonniers. Chez ces grands herbivores, la masse est importante puisqu'elle est positivement corrélée à la survie et à la reproduction. C'est pourquoi il est essentiel d'investiguer les paramètres affectant les changements de masse saisonniers. L'objectif principal de ma maîtrise était donc d'identifier et de mieux comprendre l'effet des conditions climatiques et météorologiques sur les changements de masse estivaux et hivernaux d'un ongulé alpin: le mouflon d'Amérique (Ovis canadensis). Pour atteindre cet objectif, j'ai utilisé les données du suivi à long terme de la population de mouflons de Ram Mountain, Alberta. Les mesures de masse répétées prises lors des captures permettent d'estimer la masse printanière et automnale des individus, ainsi que leur gain de masse estival et leur changement de masse hivernal. En affectant les coûts énergétiques de la thermorégulation et des déplacements et en influençant la végétation, les conditions climatiques et météorologiques peuvent avoir d'importantes conséquences sur les changements de masse des ongulés alpins. La température, les précipitations et un indice de climat global (le «Pacific Decadal Oscillation»; PDO) ont donc été utilisés afin de caractériser les conditions environnementales et d'investiguer les effets de ces variables sur les changements de masse saisonniers des individus de différentes classes d'âge et de sexe. Des températures froides au printemps ont engendré de plus grands gains de masse estivaux. Des printemps froids peuvent ralentir la maturation des plantes, engendrant une plus grande période où il est possible de s'alimenter de jeunes plantes nutritives, ce qui explique probablement cet effet positif des printemps froids. Cet effet doit toutefois être nuancé puisque les changements de masse hivernaux étaient également influencés par la température printanière, avec des printemps chauds menant à de plus faibles pertes de masse. Il semble que cet effet était dû à une apparition hâtive de la végétation, menant à une prise de masse des mouflons avant qu'ils ne soient capturés au printemps. Cela suggère qu'en affectant la disponibilité et la qualité de la végétation, les conditions printanières ont des répercussions à la fois sur le gain de masse estival, mais également sur les changements de masse hivernaux des mouflons. Le PDO au printemps a un effet positif important sur le gain de masse des adultes mâles lorsque la densité est faible. Des températures chaudes à l'automne engendrent de plus grands gains de masse pendant l'hiver chez les agneaux mâles (la plupart des agneaux gagnent de la masse l'hiver), potentiellement en augmentant la période possible de prise de masse pour ces jeunes individus. Les femelles de deux ans et les mâles adultes ont perdu plus de masse lors d'hivers avec beaucoup de précipitations et des températures froides, respectivement. Finalement, ce projet de recherche a permis d'identifier les variables climatiques et météorologiques clés affectant les changements de masse saisonniers d'un ongulé alpin. Cette étude a également mis en évidence des effets du PDO sur les changements de masse saisonniers, soulignant que de tels indices peuvent s'avérer utiles afin de les mettre en lien avec la variation phénotypique chez les espèces sauvages, et ce sans qu'il n'y ait nécessairement de fortes corrélations entre ces indices et les variables météorologiques locales.

Investigating how and why individuals interact is an important component to understanding species ecology. The type and patterning of relationships (social structure) provides pertinent insight into how ecological factors such as spatial heterogeneity of resources and predation influence associations between individuals. Many taxa exhibit temporally fluid association patterns, where individuals associate with a variety of others at different rates. Ungulate species exhibit prime examples of highly fluid grouping patterns and individuals form both temporary and long-term associations. The effects of human disturbance on ungulate behavior are well documented and these changes are further exacerbated during the hunting season. Species such as elk (Cervus canadensis) are highly managed having subsistence, recreational, and economic value. The demographic effects of selective take or harvest regimes on population dynamics are known, but how human disturbance, including hunting, influences ungulate social structure on a fine-scale has not been explored. I aimed to investigate the relationship between human disturbance and social structure in a population of elk residing in southeastern, Kentucky, USA. I choose to focus on female elk given the importance of adult female survival to population dynamics and previous knowledge of some social affinity between females. I begin by discussing factors that influence ungulate sociality, how human disturbance can influence sociality and how a better understanding of association patterns could aid in management decisions. I then present two distinct yet vital studies to understanding this relationship: (1) investigation of survival of elk in Kentucky and (2) investigation of association patterns in a human dominated landscape. Hunter harvest is the primary cause of elk mortality in both eastern and western populations in North America and 85.2% of all elk mortalities in Kentucky were hunter harvest related. Older (> 5) males and younger (< 2) females had significantly higher hazards of dying relative to other age classes. Moreover, the establishment of a limited entry hunting area to prevent local overharvest of males had no effect on male survival, but instead may have resulted in local overharvest of females at one site residing on publicly accessible land. Female elk exhibit both weak and strong association patterns. I found that relatedness was significantly greater within sites, similar to patterns found in other cervid species. Association patterns within sites were not explained by age class; and relatedness was only positively correlated at one site. The sites investigated differed in the type and frequency of human disturbance, specifically hunting, suggesting that the disparity in association patterns were driven by these differences. I conclude with two smaller studies, suggesting an indirect consequence of coal surface mining disturbance on ungulate foraging behavior and the potential for interstate transfer of ecto-parasites during reintroduction efforts. This research reinforces previous findings and further refines our understanding of ungulate social structure. Consideration of temporal variation in association patterns of ungulates and other species is important to quantify the effect of disturbance on population and social processes, but also to increase our understanding of dynamic structures. Quantifying the resiliency of structure to disturbance is a priority to further our understanding of the ecology and conservation of these species.

<p>Metal contaminated stormwater, i.e. surface runoff in urban areas, can be treated in percolation systems, ponds, or wetlands to prevent the release of metals into receiving waters. Plants in such systems can, for example, attenuate water flow, bind sediment, and directly accumulate metals. By these actions plants affect metal mobility. This study aimed to examine the accumulation of Zn, Cu, Cd, and Pb in roots and shoots of plant species common in stormwater areas. Furthermore, submersed plants were used to examine the fate of metals: uptake, translocation, and leakage. Factors known to influence metal accumulation, such as metal ion competition, water salinity, and temperature, were also examined. The following plant species were collected in the field: terrestrial plants – <i>Impatiens parviflora</i>, <i>Filipendula ulmaria</i>, and <i>Urtica dioica</i>; emergent plants –<i> Alisma-plantago aquatica</i>, <i>Juncus effusus</i>, <i>Lythrum salicaria</i>, <i>Sagittaria sagittifolia</i>, and <i>Phalaris arundinacea</i>; free-floating plants – <i>Lemna gibba</i> and <i>Lemna minor</i>; and submersed plants – <i>Elodea canadensis</i> and <i>Potamogeton natans</i>. Furthermore, the two submersed plants, <i>E. canadensis</i> and <i>P. natans</i>, were used in climate chamber experiments to study the fate of the metals in the plant–water system.</p><p>Emergent and terrestrial plant species accumulated high concentrations of metals in their roots under natural conditions but much less so in their shoots, and the accumulation increased further with increased external concentration. The submersed and free-floating species accumulated high levels of metals in both their roots and shoots. Metals accumulated in the shoots of <i>E. canadensis</i> and <i>P. natans</i> derived mostly from direct metal uptake from the water column.</p><p>The accumulation of Zn, Cu, Cd, and Pb in submersed species was in general high, the highest concentrations being measured in the roots, followed by the leaves and stems, <i>E. canadensis</i> having higher accumulation capacity than <i>P. natans</i>. In <i>E. canadensis</i> the Cd uptake was passive, and the accumulation in dead plants exceeded the of living with time. The capacity to quickly accumulate Cd in the apoplast decreased with successive treatments. Some of the Cd accumulated was readily available for leakage. In <i>P. natans,</i> the presence of mixtures of metal ions, common in stormwater, did not alter the accumulation of the individual metals compared to when presented separately. It is therefore, proposed that the site of uptake is specific for each metal ion. In addition cell wall-bound fraction increased with increasing external concentration. Further, decreasing the temperature from 20ºC to 5ºC and increasing the salinity from 0‰ to 5‰ S reduced Zn and Cd uptake by a factor of two.</p><p>In <i>P. natans</i> the metals were not translocated within the plant, while in<i> E. canadensis </i>Cd moved between roots and shoots. Thus,<i> E. canadensis</i> as opposed to <i>P. natans</i> may increase the dispersion of metals from sediment via acropetal translocation. The low basipetal translocation implies that neither <i>E. canadensis</i> nor <i>P. natans</i> will directly mediate the immobilisation of metal to the sediment via translocation.</p><p>To conclude, emergent and terrestrial plant species seem to enhance metal stabilization in the soil/sediment. The submersed plants, when present, slightly increase the retention of metals via shoot accumulation.</p>

Metal contaminated stormwater, i.e. surface runoff in urban areas, can be treated in percolation systems, ponds, or wetlands to prevent the release of metals into receiving waters. Plants in such systems can, for example, attenuate water flow, bind sediment, and directly accumulate metals. By these actions plants affect metal mobility. This study aimed to examine the accumulation of Zn, Cu, Cd, and Pb in roots and shoots of plant species common in stormwater areas. Furthermore, submersed plants were used to examine the fate of metals: uptake, translocation, and leakage. Factors known to influence metal accumulation, such as metal ion competition, water salinity, and temperature, were also examined. The following plant species were collected in the field: terrestrial plants – Impatiens parviflora, Filipendula ulmaria, and Urtica dioica; emergent plants – Alisma-plantago aquatica, Juncus effusus, Lythrum salicaria, Sagittaria sagittifolia, and Phalaris arundinacea; free-floating plants – Lemna gibba and Lemna minor; and submersed plants – Elodea canadensis and Potamogeton natans. Furthermore, the two submersed plants, E. canadensis and P. natans, were used in climate chamber experiments to study the fate of the metals in the plant–water system. Emergent and terrestrial plant species accumulated high concentrations of metals in their roots under natural conditions but much less so in their shoots, and the accumulation increased further with increased external concentration. The submersed and free-floating species accumulated high levels of metals in both their roots and shoots. Metals accumulated in the shoots of E. canadensis and P. natans derived mostly from direct metal uptake from the water column. The accumulation of Zn, Cu, Cd, and Pb in submersed species was in general high, the highest concentrations being measured in the roots, followed by the leaves and stems, E. canadensis having higher accumulation capacity than P. natans. In E. canadensis the Cd uptake was passive, and the accumulation in dead plants exceeded the of living with time. The capacity to quickly accumulate Cd in the apoplast decreased with successive treatments. Some of the Cd accumulated was readily available for leakage. In P. natans, the presence of mixtures of metal ions, common in stormwater, did not alter the accumulation of the individual metals compared to when presented separately. It is therefore, proposed that the site of uptake is specific for each metal ion. In addition cell wall-bound fraction increased with increasing external concentration. Further, decreasing the temperature from 20ºC to 5ºC and increasing the salinity from 0‰ to 5‰ S reduced Zn and Cd uptake by a factor of two. In P. natans the metals were not translocated within the plant, while in E. canadensis Cd moved between roots and shoots. Thus, E. canadensis as opposed to P. natans may increase the dispersion of metals from sediment via acropetal translocation. The low basipetal translocation implies that neither E. canadensis nor P. natans will directly mediate the immobilisation of metal to the sediment via translocation. To conclude, emergent and terrestrial plant species seem to enhance metal stabilization in the soil/sediment. The submersed plants, when present, slightly increase the retention of metals via shoot accumulation.

Song repertoire structure, organization, and use were studied in 68 male Canada Warblers (Cardellina canadensis) in a breeding population in New Hampshire in 2010-2011. On average, males had complex repertoires of 12 phrases and 55 variants. Repertoire sharing was negatively related to distance between territories, and positively related to longer territory tenure, evidence that males learn songs from neighbours. Males used two singing modes: (I) slow, regular delivery of less variable songs, and (II) fast, intermittent delivery of more variable songs interspersed with chips. Males used Mode I when unpaired and when near females, and Mode II at dawn and during territory disputes, a pattern similar to other warbler species with two song categories. Detectability (whether a male sang) differed little between 1-, 3-, 5-, and 10-min count intervals. Song output and detectability were highest at dawn and in unpaired males, and lowest in paired males late in the season.

Anthropogenic disturbances to Alberta’s landscape have resulted in the widespread removal of indigenous plant communities. Steep slopes and limited topsoil are often barriers when trying to reestablish vegetation; however, native rhizomatous grass species have a number of traits that make them ideally suited to revegetate challenging sites. A field study evaluated the establishment of three species of native perennial rhizomatous grasses (Calamagrostis canadensis, Calamovilfa longifolia, and Hierochloe odorata) from three propagation methods. Initial results suggest that these species were able to establish and survive on these sites despite poor soil conditions. Establishment was poor in seeded plots (24.1%), but improved with root cuttings (75.9%) and nursery-grown plugs (96.3%). The use of vegetative establishment methods could increase the successful application of native grass species, and encourage their use in landscape design and restoration projects. / Thank you to Imperial Oil and the Glenbow Ranch Park Foundation for providing financial and material support for this project.

The hemlock woolly adelgid, an invasive non-native insect, is threatening eastern hemlock in Kentucky. This study examined three techniques to map the distribution of eastern hemlock using decision trees, remote sensing, and species distribution modeling. Accuracy assessments showed that eastern hemlock was best modeled using a decision tree without incorporating satellite radiance. Using the distribution from the optimal model, risk maps for susceptibility to hemlock woolly adelgid infestation were created using two species distribution models. Environmental variables related to dispersal were used to build the models and their contributions to the models assessed. The models showed similar spatial distributions of eastern hemlock at high risk of infestation.

Hemlock woolly adelgid is an invasive herbivore causing extensive mortality of eastern hemlock, an important foundation species that provides stable conditions influencing biological communities. Hemlock is often found in riparian areas and following its decline, broadleaved species, including birch, beech, and rhododendron, will replace it. These plants differ from hemlock in patterns of canopy cover and leaf properties, which influence conditions and resources within streams. My goal was to evaluate potential impacts of adelgid-induced alterations to riparian canopies and litter on benthic communities and litter breakdown in streams. I characterized benthic invertebrate communities, litter colonization and litter breakdown in streams with hemlock- or deciduous-dominated riparian canopies. Riparian canopy influenced abundance of some invertebrates, but litter species influences a range of benthic colonizers. Rhododendron and beech litter generally support more invertebrates and decomposes more slowly than birch or hemlock. When invertebrates are excluded, broadleaved litter breakdown is more hindered than hemlock breakdown. My findings suggest that invertebrates may be more affected by future increases in broadleaved litter inputs to streams than by hemlock litter loss. This is significant because benthic invertebrates are important for in-stream litter processing and are linked to aquatic and terrestrial food webs.

Toxic elements are present in polluted water from mines, industrial outlets, storm water etc. Wetland plants take up toxic elements and increase the pH of the medium. In this thesis was investigated how the shoots of submerged plants and roots of emergent plants affected the pH of the surrounding water in the presence of free toxic ions. The aim was to clarify the mechanisms by which these plants change the surrounding water pH in the presence of toxic ions. The influence of Elodea canadensis shoots on the pH of the surrounding water was studied in the presence of cadmium (Cd) at low initial pH (4-5). The involvement of photosynthetic activity in the pH changes was investigated in the presence and absence of Cd. The cytosolic, vacuolar and apoplasmic pH changes as well as cytosolic Cd changes in E. canadensis were monitored. The influence of Eriophorum angustifolium roots on the pH of the surrounding water was investigated in the presence of a combination of Cd, copper, lead, zinc and arsenic at low initial pH (3.5). Eriophorum angustifolium root exudates were analyzed for organic acids. Elodea canadensis shoots increased the pH of the surrounding water, an effect more pronounced with increasing Cd levels and/or increasing plant biomass and increased plant Cd uptake. The pH increase in the presence of free Cd ions was not due to photosynthesis or proton uptake across the plasmalemma or tonoplast. Cadmium was initially sequestered in the apoplasm of E. canadensis and caused its acidosis. Eriophorum angustifolium roots increased the surrounding water pH and this effect was enhanced in the presence of arsenic and metals. This pH increase was found to depend partly on the release of oxalic acid, formic acid and succinic acid by the plants. In conclusion, E. canadensis shoots and E. angustifolium roots were found to increase the low initial pH of the surrounding water. The pH modulation by these species was enhanced by low levels of free toxic ions in the surrounding water. / At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Submitted. Paper 3: Submitted. Paper 4: Manuscript.