Η Εύβοια είναι το δεύτερο μεγαλύτερο σε έκταση νησί της Ελλάδας, στο οποίο απαντάται μεγάλη ποικιλομορφία αναγλύφου, γεωλογικού υποστρώματος και υψομέτρου, ιδιαίτερα στο βόρειο τμήμα του. Σε συνδυασμό με το κλίμα που επικρατεί, δημιουργούνται κατάλληλες συνθήκες, οι οποίες ευνοούν την ανάπτυξη σπανίων ή απειλούμενων φυτικών ειδών και υποειδών μεγάλου επιστημονικού ενδιαφέροντος. Το Quercus trojana subsp. euboica, η ευβοϊκή δρυς όπως ονομάζεται κοινώς, είναι ένα από τα ιδιαίτερα ενδιαφέροντα φυτικά taxa, τα οποία φύονται στη βόρεια Εύβοια. Μάλιστα, είναι ένα από τα στενότοπα ενδημικά taxa της Εύβοιας και ταυτόχρονα το μοναδικό ενδημικό υποείδος του γένους Quercus στην Ελλάδα. Έχει χαρακτηριστεί ως Τρωτό (VU) βάσει της κατηγοριοποίησης της IUCN (2001) σύμφωνα με το κριτήριο C1, όμως οι περιοχές εξάπλωσής του δεν υπόκεινται ακόμη σε καθεστώς νομικής προστασίας. Υφίσταται πιέσεις από ανθρωπογενείς επιδράσεις όπως πυρκαγιές, βόσκηση και υλοτομίες. Στο πλαίσιο της παρούσας εργασίας ξεκίνησε η διαδικασία παρακολούθησης (monitoring) της κατάστασης στη φύση του ενδημικού taxon Quercus trojana subsp. euboica. Ως “monitoring” ορίζονται οι επανειλημμένες μετρήσεις διαφόρων παραγόντων και μεταβλητών (αριθμός ατόμων εκάστοτε taxon, ύψος-διάμετρος κορμού, εδαφοκάλυψη, ανθοφορία, καρποφορία, φυτρωτικότητα ατόμων, βιωσιμότητα αρτιφύτρων κ.ά.) σε βάθος χρόνου και σε έκταση. Τοποθετήθηκαν δέκα συνολικά επιφάνειες παρακολούθησης επιφάνειας 25 m2 η καθεμία στις περιοχές εξάπλωσής του, με επιμέρους υποτετράγωνα 1 m2. Πραγματοποιήθηκε έρευνα επί τρία έτη και καθ’ όλη τη διάρκεια του έτους. Πάρθηκαν ποικίλες μετρήσεις (γεωγραφικό μήκος-πλάτος, υψόμετρο, κλίση-έκθεση, εδαφολογικές παρατηρήσεις), ενώ συλλέχθηκαν φυτικά δείγματα για την πλήρη χλωριδική ανάλυση και φωτογραφήθηκε λεπτομερώς κάθε επιφάνεια. Πραγματοποιήθηκε ταξινομικός προσδιορισμός των δειγμάτων βάσει της πλέον πρόσφατης βιβλιογραφίας, έγινε προσδιορισμός των βιομορφών, διάκριση των χωρολογικών στοιχείων και φυτοκοινωνιολογική ανάλυση σύμφωνα με τη μέθοδο Braun-Blanquet. Έτσι, βρέθηκαν 93 taxa στις περιοχές εξάπλωσης της ευβοϊκής δρυός, με κυρίαρχες οικογένειες την Asteraceae (17%) και την Poaceae (6%). Τα Ημικρυπτόφυτα αποτελούν σχεδόν το 41% του συνόλου, ενώ το 44,1% είναι Μεσογειακά taxa. Επίσης, παρατηρήθηκαν 18 ελληνικά ενδημικά taxa, εκ των οποίων τα 6 είναι στενότοπα ενδημικά. Έπειτα, όλες οι δειγματοληπτικές επιφάνειες καταχωρήθηκαν στη βάση δεδομένων Turboveg και χρησιμοποιήθηκε το πρόγραμμα TWINSPAN (two-way indicator species analysis) για να ομαδοποιηθούν οι φυτοληψίες. Ακόμη, χρησιμοποιήθηκε η μέθοδος DCA (Detrended Correspondence Analysis-DECORANA) για τη δημιουργία γραφικής απεικόνισης του πίνακα των φυτοκοινωνιολογικών δεδομένων. Επιπλέον, χρησιμοποιώντας το πρόγραμμα SPSS 13.0 πραγματοποιήθηκε Ανάλυση Ομαδοποίησης (Cluster Analysis) με τη μέθοδο Σύνδεσης Γειτόνων (Neighbor Joining) για τις δέκα επιφάνειες παρακολούθησης. Ο δείκτης που χρησιμοποιήθηκε είναι αυτός της παρουσίας-απουσίας ειδών Jaccard. Όπως προκύπτει από τη μελέτη αυτή, οι περιοχές εξάπλωσης της ευβοϊκής δρυός φαίνεται να έχουν υποστεί συρρίκνωση από την πυρκαγιά του 1977, ενώ οι πληθυσμοί της κινδυνεύουν από τη διαρκή πίεση της βόσκησης. Τέλος, προτείνονται μέτρα για την καλύτερη πρoστασία του Quercus trojana subsp. euboica. / Evvia is the second largest greek island, which is characterized by a great variety of terrain, geologic substrate and altitude, especially in its northern part. In combination with the climate, the appropriate conditions are met that favor the evolvement of rare or endangered plant species and subspecies of great scientific interest. Quercus trojana subsp. euboica, the euboean oak as it is commonly reffered to, is one of the most interesting plant taxa that grow in northern Evvia. Not only is it one of the local endemic taxa of northern Evvia, but it is the unique endemic subspecies of the Quercus genus in Greece. It has been characterized as vulnerable (VU) according to the IUCN (2001) categories and the C1 criteria, though it has yet not been included in a protectin law regime. It has been under the constant pressure of human impact such as fire, browsing and timbering. During this study, monitoring the status of the endemic taxon Quercus trojana subsp. euboica has begun. The monitoring process involves the repeated measurement of multiple factors and variables (such as measurement of height/diameter, soil-coverage, florescence, fruition, germination/viability of individuals etc.) in a length of time and area extent. A number of ten monitoring plots was set, each plot occupying a surface of 25 m2 in total, with 25 subplots of 1 m2. The study lasted three years and was conducted throughout the year. Multiple measurements took place (geographic length and width, altitude, gradient, exposure etc.), while plant samples were collected in the framework of a full floristic analysis and each monitoring plot was thoroughly photographed. A taxonomic assessment of the plant samples was conducted according to the latest bibliography, as well as a distinction of biomorphs and geographic elements. Moreover, a phytosociologic analysis was conducted according to the Braun-Blanquet method. Thus, 93 different taxa were found in the vicinity of the territories that Quercus trojana subsp. euboica takes up. Asteraceae and Poaceae families were found to be dominant in the plots with a percentage of 17% and 6% respectively. Hemicryptophyts represent 41%, while the Mediterranean elements dominate with a percentage of 44,1%. Nevertheless, 18 greek endemic plant taxa were found, 6 of which are local endemics of Evvia. Thereinafter, all of the monitoring plots were registered in the TurboVeg database and the TWINSPAN (Two-way indicator species analysis) program was used in order to group the plots. Furthermore, the DCA method (Detrended Correspondence Analysis-DECORANA) was used for the creation of a graphic display of the phytosociologic data index. The SPSS 13.0 program was used so that a Cluster Analysis was conducted, using the Neighbor Joining Method for the 10 plots. The Jaccard presence-absence indicator was used. In a nutshell, this study showed that Quercus trojana subsp. euboica territories of appearance have been reduced after the 1977 wildfire, while the taxon’s population is in danger due to the constant pressure of goat grazing. Concluding, measures for better protection of the taxon are proposed.

Understanding species-habitat relationships for endangered species is critical for their conservation. However, many studies have limited value for conservation because they fail to account for habitat associations at multiple spatial scales, anthropogenic variables, and imperfect detection. We addressed these three limitations by developing models for an endangered wetland bird, Yuma Ridgway's rail (Rallus obsoletus yumanensis), that examined how the spatial scale of environmental variables, inclusion of anthropogenic disturbance variables, and accounting for imperfect detection in validation data influenced model performance. These models identified associations between environmental variables and occupancy. We used bird survey and spatial environmental data at 2473 locations throughout the species' U.S. range to create and validate occupancy models and produce predictive maps of occupancy. We compared habitat-based models at three spatial scales (100, 224, and 500 m radii buffers) with and without anthropogenic disturbance variables using validation data adjusted for imperfect detection and an unadjusted validation dataset that ignored imperfect detection. The inclusion of anthropogenic disturbance variables improved the performance of habitat models at all three spatial scales, and the 224-m-scale model performed best. All models exhibited greater predictive ability when imperfect detection was incorporated into validation data. Yuma Ridgway's rail occupancy was negatively associated with ephemeral and slow-moving riverine features and high-intensity anthropogenic development, and positively associated with emergent vegetation, agriculture, and low-intensity development. Our modeling approach accounts for common limitations in modeling species-habitat relationships and creating predictive maps of occupancy probability and, therefore, provides a useful framework for other species.

Increasing sea levels and anthropogenic disturbances have caused the world’s coastal vegetation to decline 25-50% in the past 50 years. Future sea level rise (SLR) rates are expected to increase, further threatening coastal habitats. In combination with SLR, the Everglades ecosystem has undergone large-scale drainage and restoration changing Florida’s coastal vegetation. Everglades National Park (ENP) has 21 coastal plant species threatened by SLR. My dissertation focuses on three aspects of coastal plant community change related to SLR and dehydration. 1) I assessed the extent and direction coastal communities—three harboring rare plant species—shifted from 1978 to 2011. I created a classified vegetation map and compared it to a 1978 map. I hypothesized coastal communities transitioned from less salt- and inundation-tolerant to more salt- and inundation-tolerant communities. I found communities shifted as hypothesized, suggesting the site became saltier and wetter. Additionally, all three communities harboring rare plants shrunk in size. 2) I evaluated invading halophyte (salt-tolerant) plant influence on soil salinity via a replacement series greenhouse experiment. I used two halophytes and two glycophytes (non-salt-tolerant) to look at soil salinity over time under 26 and 38‰ groundwater. I hypothesized that halophytes increase soil salinity as compared to glycophytes through continued transpiration during dry, highly saline periods. My results supported halophytic influence on soil salinity; however, not from higher transpiration rates. Osmotic or ionic stress likely decreased glycophytic biomass resulting in less overall plant transpiration. 3) I assessed the best plant life-stage to use for on-the-ground plot-based community change monitoring. I tested the effects of increasing salinity (0, 5, 15, 30, and 45‰) on seed germination and seedling establishment of five coastal species, and compared my results to salinity effects on one-year olds and adults of the same species. I hypothesized that seedling establishment was the most vulnerable life-stage to salt stress. The results supported my hypothesis; seedling establishment is the life-stage best monitored for community change. Additionally, I determined the federally endangered plant Chromolaena frustrata’s salinity tolerance. The species was sensitive to salinity >5‰ at all developmental stages suggesting C. frustrata is highly threatened by SLR.

Les marges de tourbières sont des écotones marqués par la présence de communautés végétales et de conditions édaphiques singulières. Elles sont généralement étudiées sur des sites naturels ou légèrement perturbés. L’objectif de ce projet est de déterminer les fonctions et la structure de ces marges dans un contexte de perturbations anthropiques, notamment l’isolement des tourbières dans une matrice agricole. L’étude porte sur la végétation et le sol de 21 transects marge-centre répartis également entre trois tourbières des basses terres du Saint-Laurent (Lac-à-la-Tortue, Mer Bleue et Alfred) qui représentent un gradient de perturbations. Les tourbières moins perturbées comme Lac-à-la-Tortue et Mer Bleue ont une végétation et une biogéochimie similaires à ce qui est observé ailleurs sur d’autres sites non perturbés. Les marges de la tourbière Lac-à-la-Tortue ne présentent aucune communauté végétale particulière alors que les marges de Mer Bleue ont au moins une ou deux communautés végétales de transition. Néanmoins, la présence de certaines espèces exotiques envahissantes, comme Frangula alnus et Phragmites australis subsp. australis, indique que les marges de la tourbière Mer Bleue subissent malgré tout l’influence des activités anthropiques environnantes. D’autre part, les marges naturelles de la tourbière Alfred ont été détruites par les activités agricoles et les marges actuelles étaient représentatives de sites fortement perturbés avec un dépôt de tourbe plus épais et une nappe phréatique plus basse qu’attendu à la limite de la marge. Le drainage intense des marges d’Alfred semble favoriser la croissance d’arbres et d’arbustes non spécifiques aux milieux humides. Par ailleurs, les conditions sèches des marges laissent présager une diminution de la capacité de stockage du carbone dans cette tourbière. Ceci témoigne de l’importance que devraient occuper les marges des tourbières dans les projets de conservation et de restauration des tourbières. / Peatland margins are ecotones characterized by their unique plant communities and edaphic conditions. However, they are usually studied in locations where the pressure from anthropogenic activities is relatively low. The goal of this project is to evaluate the functions and structure of ombrotrophic peatland margins in the context of anthropogenic disturbance. This project is based on the analysis of data collected on 21 transects distributed across three peatlands of the Saint Lawrence valley region (Lac-à-la-Tortue, Mer Bleue, and Alfred) chosen to represent a gradient of disturbance. The vegetation composition and biogeochemistry of the least disturbed sites (Lac-à-la-Tortue, and Mer Bleue) are similar to other undisturbed sites. Lac-à-la-Tortue margins do not have any transitional vegetation community while Mer Bleue margins have either one or two transitional communities. Nevertheless, exotic species such as Phragmites australis subsp. australis and Frangula alnus found on Mer Bleue raise concern regarding the ongoing urbanisation and agricultural activities around the peatland. On the other hand, Alfred's natural margins were destroyed by anthropic activities in the surrounding landscape which explains why we measured a thicker peat layer and a deeper water table than expected at the margin limits. The severe drainage of Alfred margins due to agriculture around the peatland is also responsible for the higher tree coverage and non-wetland species encroachment on its margins. The effect of this disturbance raises concern about the capacity of the margins nay the peatland to retain its carbon sequestration capacity. This study emphasizes the importance of integrating the peatland margins in conservation and restoration projects.

Greater sage-grouse populations have decreased steadily since European settlement in western North America. Reduced availability of brood-rearing habitat has been identified as a limiting factor for many populations. We used radio-telemetry to acquire locations of sage-grouse broods from 1998 to 2012 in Strawberry Valley, Utah. Using these locations and remotely-sensed imagery, we proceeded to 1) determine which features of brood-rearing habitat could be identified using widely available, fine-scale imagery 2) assess the scale at which sage-grouse selected brood-rearing habitat in our study area, and 3) create a predictive habitat model that could be applied across our large study area to identify areas of preferred brood-rearing habitat. We used AIC model selection to evaluate support for a list of variables derived from remotely-sensed imagery. We examined the relationship of explanatory variables at three scales (45, 200, and 795 meter radii). Our top model included 10 variables (percent shrub, percent grass, percent tree, percent paved road, percent riparian, meters of sage/tree edge, meters of riparian/tree edge, distance to tree, distance to transmission lines, and distance to permanent structures). Variables from each scale were represented in our top model with the majority of scale-sensitive variables suggesting selection at the larger (795 meter) scale. When applied to our study area our top model predicted 75% of naive brood locations suggesting reasonable success using this method and widely available NAIP (National Agricultural Imagery Program) imagery. We encourage application of this method to other sage-grouse populations and species of conservation concern. The northern river otter is a cryptic semi-aquatic predator that establishes and uses latrines. Highly used river otter latrines indicate otter "activity centers" since frequency of scat deposition is thought to be correlated to frequency of habitat use. We compared an indirect method (scat counts) and a direct method (remote cameras) of determining latrine utilization in order to assess the accuracy of the commonly used indirect method. To further compare these methods we used them to examine effects of anthropogenic disturbance on otters of the Provo River in Utah. We found that overall the direct and indirect methods were highly correlated. There was significant seasonal variation in the degree of correlation between the indirect and direct methods with correlation being significantly higher in the summer. We found similar results when using these methods to examine effects of anthropogenic disturbance. For each method the distance of the latrine to trails was significant in one of the top competing models. We suggest that space use of otters in our study area is being affected by anthropogenic disturbance as measured by distance to trails. We also suggest that scat counts should only be conducted during the summer when they correlate best with actual levels of otter activity.

Biodiversity is being lost around the world and anthropogenic activities, like non-native species introductions and urbanization, are among the leading causes of decline. Broadening our understanding of human-driven impacts on biodiversity can lead to more effective solutions and contribute towards stemming biodiversity losses. In this thesis, I explored the impacts of non-native species introductions and urbanization on butterfly-plant communities. I evaluated potential factors influencing the range expansion of a newly introduced species (Chapter 1), examined the role of urbanization in structuring biological communities (Chapter 2), and identified important ecological interactions between native and non-native species (Chapter 3). In my first chapter, I found that the newly introduced European Common Blue butterfly (Polyommatus icarus) was more abundant in urban and disturbed habitat that was unmown and where their preferred larval host plant (Lotus corniculatus), a non-native species, was present. I also found that P. icarus was not a strong flier relative to other butterfly species, suggesting that adult dispersal may not be a driving factor in range expansion. Instead, this species could expand its range in the future by colonizing habitats in developed regions across Canada given the association I found between P. icarus and disturbed habitat. In my second chapter, I found that urbanization led to the biotic homogenization of butterfly communities around Montréal, QC, favouring a few, highly abundant, non-native species. Homogenization was detected at both the taxonomic and functional levels and was driven by increases in P. icarus abundance in the more urban sites. In my third chapter, I found that non-native plants were well integrated into native butterfly nectar diets in an at-risk oak savanna ecosystem on Vancouver Island, BC and that usage of non-native plants increased when they were more available during the season. I also found that native butterflies visited non-native plants more often than flower availability predicted on its own, suggesting that butterflies may even prefer non-native nectar. Findings from my thesis research broaden our understanding of the ways in which butterfly communities can be influenced by human activities like urbanization and the introduction of non-native species, informing conservation efforts and directing future research needs.

No description available.

Effective management of the potential environmental impacts of naval sonar requires quantitative data on the behaviour and hearing physiology of cetaceans. Here, novel experimental and analytical methods were used to obtain such information and to test the effectiveness of an operational mitigation method for naval sonar. A Bayesian method was developed to estimate whale locations through time, integrating visual observations with measurements from on-animal inertial, acoustic, depth, and Fastloc-GPS sensors. The track reconstruction method was applied to 13 humpback whale (Megaptera novaeangliae) data sets collected during a multi-disciplinary behavioural response study in Norwegian waters. Thirty-one controlled exposure experiments with and without active transmissions of 1.3-2 kHz sounds were conducted using a moving vessel that towed a sonar source. Dose-response functions, representing the relationships between measured sonar dose and behavioural responses identified from the reconstructed tracks, predicted that 50% of the humpbacks would initiate avoidance at a relatively high received sound pressure level of 166 dB re 1 µPa. Very similar dose-response functions were obtained for cessation of feeding. In a laboratory study, behavioural reaction times of a harbour porpoise (Phocoena phocoena) to sonar-like sounds were measured using operant conditioning and a psychoacoustic method. Auditory weighting functions, which can be used to improve dose-response functions, were obtained for the porpoise based on the assumption that sounds of equal loudness elicit equal reaction time. Additional analyses of the humpback whale data set provided evidence that ramp-up of naval sonar mitigates harmful sound levels in responsive cetaceans located directly in the path of the source, and suggested that a subset of the humpback whale population, such as mother-calf pairs, and more responsive species would benefit from the use of sonar ramp-up. The findings in this thesis are intended to inform sound exposure criteria and mitigation guidelines for anthropogenic noise exposure to cetaceans.

L’usage des véhicules tout-terrain (VTT) est largement répandu en Minganie, municipalité régionale de comté reconnue pour ses grandes étendues de tourbières. Ce mémoire vise à comprendre les effets de cette perturbation linéaire en déterminant la distance d’influence des sentiers de VTT sur la végétation et les caractéristiques physiques des tourbières. De plus, il vise à déterminer l’ampleur de l’impact en fonction des caractéristiques des sentiers (largeur, profondeur et nombre de sillons). Répartis dans un rayon de 200 km autour de la municipalité de Havre-Saint-Pierre, 18 transects d’échantillonnage ont permis de constater un effet localisé et limité des sentiers de VTT sur la végétation et les variables abiotiques. Un sol dénudé et une plus grande densité de la tourbe ont été observés à l’emplacement du sentier. De plus, une couverture végétale plus faible a été constatée dans les sentiers, car près du quart des espèces ne résistent pas aux passages des VTT. Quatre espèces indicatrices associées aux placettes hors sentier (K. angustifolia, R. groenlandicum, C. rangiferina et S. fuscum) semblent partager des caractéristiques communes (p. ex. : forme érigée, branches basses et ligneuses, thalle friable) les rendant moins tolérantes aux passages des VTT. Certains sentiers couvrent des zones très étendues, surtout s’ils sont dans des zones fortement humides, de sorte que l'impact global du passage des VTT, bien que limité aux sentiers eux-mêmes, peut être très important localement. Puisque l'utilisation des VTT est une pratique en croissance dans la région, une gestion de leur utilisation dans les milieux sensibles ou une sensibilisation des utilisateurs de VTT sur les conditions des tourbières pourrait réduire les effets négatifs et assurer un usage durable pour maintenir les services écologiques fournis par les tourbières. / All-terrain vehicles (ATVs) are widely used in Minganie, a region known for its vast expanses of peat bogs. This thesis aims to understand the effects of this linear disturbance by determining the distance of influence of ATV trails on the vegetation and physical characteristics of the peatlands. In addition, it aims to determine the magnitude of the effect based on trail characteristics (width, depth, and number of ruts). Located within a 200 km radius of the municipality of Havre-Saint-Pierre, 18 sampling transects revealed a localized and limited effect of ATV trails on vegetation and abiotic variables. Bare soil and higher peat density were observed at the trail location. In addition, lower vegetation cover was observed on the trails, as nearly a quarter of the species did not survive the ATV passages. Four indicator species associated with the off-trail plots (K. angustifolia, R. groenlandicum, C. rangiferina, and S. fuscum) appear to share common characteristics that make them less tolerant of ATV traffic (i.e., erect form, base-branched woody stems, brittle thallus). Some trails cover wide areas, especially if they are in very wet areas, hence the global impact of ATV passage, while limited to the trails themselves, can be quite severe locally. Since ATV use is a growing activity in the region, managing ATV use in sensitive areas or awareness among ATV users about peatland conditions could reduce negative impacts and ensure sustainable use to maintain the ecosystem services provided by peatlands.

Of concern in this research were the ecological parameters associated with the establishment of a model invasive plant species, Imperata cylindrica, across a scale of ecological organization. Specifically, the study addressed the species’ ability to: differentially respond to abiotic and biotic constraints during seedling establishment, exhibit a novel underground competitive interference mechanism, and alter the decomposition dynamics in newly invaded ecosystems. Finally, the last portion of the research was centered around creating a predictive habitat model that will provide information on the most important variables responsible for creating habitat for this species. The population level seedling study indicated that soil characteristics and light availability play a significant role in seedling establishment. There were large trends in biomass allocation attributable to soil type with seedlings performing best in high nutrient soils representative of the Mississippi Alluvial Valley physiographic region. I. cylindrica seedlings also showed a positive response to increased seedling density during the initial stages of seedling establishment. The community level research examining a hypothesized novel interference mechanism deployed by I. cylindrica showed a significant and robust pattern of I. cylindrica damaging its own belowground tissue more often than that of its surrounding neighbors. Therefore, it is highly unlikely that I. cylindrica gains a competitive advantage by exposing the native plant assemblage to pathogen invasion (via ruptured tissue) as the plant would expose itself to these pathogens (to which it is evolutionarily naive) at much higher volumes. The ecosystem level examination of this globally important invasive species indicated that I. cylindrica invasion into native systems will significantly accelerate ambient rates of decomposition. Furthermore, fungal community composition in invaded areas was drastically altered as well as bacterial community functional activity in relation to several key enzymes responsible for the decomposition of plant tissue which were produced more abundantly in invaded areas.The landscape-scale analyses and modeling work validated decades of anecdotal evidence and indicated that anthropogenic disturbance factors associated with road maintenance and construction (soil disturbance and vegetation removal) are the principal factors responsible for creating habitat suitable for invasion by this species.