Understanding the impacts of both natural and anthropogenic landscape features on genetic diversity, population structure and connectivity has important implications for conservation of species living in fragmented environments. Here, I combine population genetic data, detailed land cover information, and computer simulations to explore how landscape shapes genetic structure across two regional populations of the threatened eastern massasauga rattlesnake (Sistrurus catenatus catenatus) in Ontario, Canada: one along the eastern shores of Georgian Bay and the other largely confined to the northern half of the Bruce Peninsula. First I used spatial Bayesian assignment to quantify the genetic population structure within each regional population. I found marked subpopulation structure within eastern Georgian Bay with differentiation of island and mainland snakes, a north-south split within the mainland coinciding with the town of Parry Sound, and evidence of further subdivision within the cluster of snakes north of Parry Sound. In contrast I found no population subdivision within the mainland of the Bruce Peninsula, but genetic distinction of mainland and island snakes. Next, I identified the landscape features that shape spatial genetic structure within regional populations. In eastern Georgian Bay I found local variation in the effect of landscape on populations. North of Parry Sound I found no effect of landscape on inter-individual genetic differentiation, but a strong pattern of isolation-by-distance. In contrast I found that both open water and roads restrict gene flow of snakes south of Parry Sound. I found no evidence of isolation-by-distance or that landscape shape genetic structure within the Bruce Peninsula. Finally I used individual-based, spatially explicit simulations to identify the lag-time associated with the detection of contemporary landscape feature effects on genetic structure of massasaugas, and explore the consequences of using spatially correlated land cover elements in landscape genetic analyses. I found that the genetic consequences of roads could be detected within 2-12 generations when population sizes were small or juvenile dispersal was low. However, I also found that roads could be spuriously identified as impediments to gene flow when spatially correlated features such as water are included in genetic models. / Thesis (Master, Biology) -- Queen's University, 2011-10-14 15:06:35.956

The changes that Swedish agriculture has undergone during the 20th century has resulted in strongly increased productivity, but at the cost of more intensive environmental impacts. One of these is loss of biodiversity, which is driven by, e.g., usage of pesticides and loss and fragmentation of habitats. A vital process for resilient ecosystems is the possibility for species to move between habitats, known as connectivity. One approach to increase connectivity is through strategic perennialization in the agricultural landscape. The aim of this thesis is to map structural connectivity in agricultural landscapes in two major agricultural regions in Sweden and explore options for enhancing connectivity by strategic perennialization. Objectives include the development of a model to map structural connectivity in the Swedish agricultural landscape, identify landscapes where conditions for biodiversity can be improved by strengthening the structural connectivity, and investigate the potential to improve the conditions for biodiversity by introducing perennial crops in the agricultural landscape. The resulting model is based on circuit theory using the software Circuitscape, in which land cover is treated as electric circuits, which are assigned resistance based on the permeability of different types of land cover. The resistance in the developed model is based partly on human impact and partly on structural differences from areas of high biological values, or value cores, between which connectivity is modelled, in terms of object height- and cover. Two agricultural production areas were investigated, Skåne plains and Västra Götaland plains, as well as a testing area in Skåne county. Connectivity maps were created and analysed, and potential areas for strategic perennialization were identified. A strategic perennialization scenario was also modelled in the testing area. Since the application of the model is structural connectivity, uncertainties regarding how well it relates to functional connectivity varies between species. Structural connectivity has nonetheless been shown to facilitate functional connectivity in several aspects. No significant difference in connectivity could be found in the trial area following the introduction of strategic perennialization, but this is most likely due to assumptions behind area selection. Therefore, other approaches for identifying promising locations for strategic perennialization, based on connectivity maps, need to be explored. / <p>2020-06-13</p>

The growing demand for urban areas has been a driving force for extensive changes to landscape. Thisrequires more focus on finding a balance between promoting urban development, and conservingbiodiversity in urban areas. The Intergovernmental Science-Policy Platform on Biodiversity andEcosystem Services (“IPBES”) suggests encouraging sustainable urban planning, as well as“maintaining, and designing for, ecological connectivity in urban spaces”. Ecological connectivity canbe modelled based on circuit theory. Landscape can be depicted as a conductive surface and resistancecan be attributed to landscape types according to its permeability to the movement of a species.Frösön is a district in the growing municipality of Östersund, Sweden, where several developmentplans are intended. This study aimed to identify where structural ecological connectivity existed inFrösön. It also aimed to determine where connectivity was disturbed by urban development, andexplore the options available to strengthen connectivity through establishing new ecological corridors.Land cover data was analysed to identify the forest patches that were larger than 50 000m2, andresistance values were attributed per land cover type. Circuitscape was used to model the connectivitybetween the forest patches, revealing the connectivity across Frösön. The development plans wereassessed to determine where the developments overlapped existing corridors with high connectivityvalues between forest patches. New corridors (pathways connecting high connectivity valuesbetween forest patches) that could compensate for the impact by development plans on connectivityas well as strengthen connectivity throughout Frösön were proposed. The findings in this reportconcur with the IPBES that urban development can be sustainable while preserving biodiversity.Additionally, the inclusion of connectivity models in the environmental impact assessment (“EIA”)process for developments, enables proactive decision-making on the design and location ofdevelopments. Moreover, it encourages urban development and the preservation of landscapeconnectivity. This study will be valuable to environmentalists carrying out EIAs and specialists thatopine on environmental policy and/or legislation. / <p>2022-0604</p>

No description available.

La perte actuelle de biodiversité demande d’augmenter la superficie des territoires protégés, dans le but de réduire la perte d’habitat, leur fragmentation, et d’atténuer les impacts des changements climatiques. Cependant, un défi majeur demeure: quelles parties d'un paysage faut-il protéger ? Le potentiel de connectivité du paysage a été un des facteurs les plus utilisés dans les dernières années. Les méthodes actuelles d’estimation de connectivité présentent toutefois des lacunes non seulement quant au nombre d'espèces simulées, mais surtout quant à leur diversité taxonomique et fonctionnelle. Ici, j’améliore l'étude de la connectivité du paysage de trois manières: j’évalue le potentiel de connectivité du paysage en m’appuyant sur un modèle d’ensemble de 93 espèces, comprenant des espèces terrestres, aviaires et semi aquatiques; j’intègre les écosystèmes aquatiques et terrestres; enfin, j'utilise un modèle plus réaliste de déplacements d’espèces fauniques. Afin de développer la méthode, j’ai utilisé des données spatiales d’un territoire de la région des Laurentides au Québec qui présente un fort gradient anthropique, du sud (fortement urbanisé et agricole) au Nord (très peu urbanisé et largement forestier). J'ai analysé la connectivité du paysage pour les espèces fauniques en utilisant Omniscape. Ce programme permet des simulations omnidirectionnelles, lesquelles représentent mieux les mouvements des animaux; jusqu’à présent la majorité des évaluations de connectivité sont unidirectionnelles (déplacement du point A au point B). J’ai ensuite regroupé les résultats de simulations de dispersion par des analyses de regroupement (Fuzzy C-mean et Ward), obtenant trois groupes. Les résultats ont confirmé que la région délimitée par le Bouclier canadien contribue grandement aux déplacements des espèces terrestres et aquatiques alors que la région située dans les basses terres du Saint-Laurent y contribue très peu. Mes résultats soulignent également que les milieux aquatiques semblent jouer un rôle important pour la connectivité globale de la région des Laurentides, puisque plusieurs espèces (dont des espèces considérées « terrestres ») les utiliseraient pour se déplacer. Je soutiens donc qu'il est essentiel de mieux intégrer les habitats aquatiques et terrestres dans une compréhension holistique de la connectivité du paysage. / The present biodiversity loss required to increase the area of protected areas in order to reduce habitat loss, fragmentation, and mitigate the impacts of climate change. However, a major challenge remain: which parts of a landscape should be protected? The landscape connectivity potential has been one of the main factors used in recent years. However, current methods of estimating connectivity have shortcomings, not only in terms of the number of species simulated, but especially in terms of their taxonomic and functional diversity. Here, I improve the study of landscape connectivity in three ways: I assess the connectivity potential of the landscape based on a pool of 93 species, including terrestrial, avian and semi-aquatic species; I integrate aquatic and terrestrial ecosystems; and finally, I use a more realistic model of movements of wildlife species. In order to develop the method, I used spatial data from a territory in the Laurentides region of Quebec, which has a strong anthropogenic gradient from the South (highly urbanized and agricultural) to the North (very little urbanized and largely forested). I analyzed landscape connectivity for wildlife species using the program Omniscape. It allows omnidirectional simulations, which better represent the movements of animals; so far, the majority of connectivity assessments were unidirectional (from point A to point B). I then pooled the results of dispersion simulations by clustering analyzes (Fuzzy C-mean and Ward), which resulted in three groups. The results confirmed that the region delimited by the Canadian Shield contributes greatly to the movement of terrestrial and aquatic species, while the region located in the St. Lawrence Lowlands do not contribute that much. My results also underline that aquatic environments seem to play an important role in the overall connectivity of the Laurentian region, since several species (including species considered “terrestrial”) use them to move around. I therefore argue that it is essential to better integrate aquatic and terrestrial habitats into a holistic understanding of landscape connectivity.