The Roanoke logperch (Percina rex) is a federally endangered large darter that occurs only within the Roanoke and Chowan drainages of Virginia. This dissertation examines multi-scale habitat use patterns by logperch in three river systems in Virginia, including comparisons among rivers and life stages. The first study in this dissertation compares microhabitat use patterns of logperch among the Roanoke, Pigg, and Nottoway rivers. My objectives are to: 1) compare available microhabitat and microhabitat use by logperch among these rivers; and 2) examine the transfer of habitat models among rivers. Habitat availability in the three rivers indicates that the Nottoway River is least impacted by human activity, while the Pigg River is most impacted. The Roanoke and Pigg rivers are found within the same region of Virginia and share many habitat characteristics. Logperch consistently use silt free, loosely embedded gravel in all rivers and can occupy a variety of depths and velocities to accommodate substrate requirements. Microhabitat models transfer better between the similar Pigg and Roanoke rivers. The second study in this dissertation compares micro- and meso-habitat use patterns by Roanoke logperch in the Roanoke and Nottoway rivers. My objectives are to: 1) compare micro- and meso-habitat use patterns of logperch in the Roanoke and Nottoway rivers; and 2) examine transfer of habitat models at both scales. An increase in scale from micro- to meso- habitat did not improve model transfer. Habitat selectivity and transfer was strongest at the microhabitat scale. Logperch appear to be microhabitat substrate specialists and mesohabitat generalists. The final study in this dissertation examines ontogenetic patterns of habitat use by Roanoke logperch in the Roanoke and Nottoway rivers. My goals are to: 1) examine habitat use by three age classes of logperch and 2) compare ontogenetic patterns of habitat use between the Roanoke and Nottoway rivers. In the Roanoke River, adult and subadult logperch primarily used run and riffle habitat, often over gravel substrate. Subadults were found in lower water velocities and more embedded microhabitats than adults. Young-of-year logperch were found in shallow, stagnant backwaters and secondary channels. In the Nottoway River, both adult and subadult logperch were found over sand and gravel in deep, low velocity pools and runs. Subadults were observed in slightly more silted, lower velocity habitat. Younger age classes of logperch appear to be more vulnerable to sedimentation caused by human activity. Evidence in this dissertation strongly indicates that logperch have strict substrate requirements and the distribution of habitat types and pathways of dispersal will be critical for completion of the logperch life cycle. A watershed-level conservation approach that addresses sediment loading and preserves ecological processes that provide ephemeral, seasonal, and persistent types of habitat required over logperch ontogeny will be most effective for management geared towards the recovery of this endangered species. / Ph. D.

La forêt n’est pas un espace naturel comme nous l’avons longtemps pensé. En utilisant l’ensemble des services que lui offre la forêt, l’homme influence la dynamique des espaces forestiers. L’objectif de cette thèse, s’inscrivant dans le champ de l’histoire de l’environnement, est d’analyser, dans le temps long, les interrelations entre paysages et sociétés riveraines, d’identifier les ruptures et continuités paysagères qui ont jalonné l’histoire forestière de l’Avesnois pour aboutir à ce que nous connaissons aujourd’hui. Cette recherche a été menée dans le cadre d’un contrat Cifre participant au Plan Forêt Régional - dont l’objectif est de doubler la superficie boisée sur l’ensemble du territoire d’ici une vingtaine d’années- et au Schéma Régional de Cohérence Ecologique Trames Vertes et Bleues. Ce dispositif en Sciences humaines et plus particulièrement en Histoire étant rare, il a fallu construire une démarche au carrefour de la démarche fondamentale et la démarche appliquée. Car non seulement il s’agissait d’analyser les modalités des actions humaines et leurs impacts sur les espaces forestiers mais il fallait plus particulièrement répondre à une demande des acteurs du monde forestier actuel conditionnant ainsi certaines problématiques scientifiques. Essentiel à la compréhension des interactions entre l’homme et son milieu, l’emboîtement des échelles spatio-temporelles constitue le cœur de cette recherche. La prise en considération de l’importance des emboîtements des échelles d’analyses, impliquant un croisement de sources de nature variée, ont conduit à une réflexion sur les outils et les méthodes à employer pour répondre aux questionnements initiaux. Tout en composant avec les limites des sources qu’il étudie, l’historien offre un recul sur les processus spatio-temporels qui ont fabriqué le paysage forestier d’aujourd’hui. Cette distanciation est nécessaire pour mener à bien les politiques environnementales actuelles : préserver un paysage, sa biodiversité doit nécessairement interroger le temps. / The forest is not a space natural as we thought of it for a long time. By using all the services which offers him the forest, the man influences the dynamics of the forest spaces. Our objective is to analyse, in the long time, the relations between landscapes and societies, to reveal the weight of the silvicultural inheritances in the contemporary sylvo-systems, to identify the breaks and the continuities of the landscape which marked out the forest history of the Avesnois, to end what we know today. This research was led within the framework of a Cifre contract participating in the Plan Forest Regional – the objectif of which is to double the surface afforested on the whole territory- and in the Regional Plan of Ecological Coherence Green and blue Wefts. This Cifre contract in Human sciences and more particularly in History being rare, it was necessary to build an approach in the crossroads of the fundamental approach and the applied approach. Because not only it was a question of analyzing the modalities of the human actions and their impacts on the forest spaces but it was more particularly necessary to answer a demand of the actors of the current forest world, conditioning certain scientific problems. The main part in the understanding of the interactions between the man and its environnement, the crossing of the spatiotemporal scales establishes the heart of this research. The taking into consideration of the importance of the crossings of the scales of analyse, implying a crossing of sources of varied nature, led to a reflection on tools and methods to use to answer the initial questionings. While composing with the limits of the sources which he studies, the historian offers a backward movement on the spatiotemporal processes which made the forest landscape of today. This distance is necessary to bring to a successful conclusion the current environmental policies : to protect a landscape, its biodiversity, it is inevitable to resort to the past.

Submitted by Mariana Dornelles Vargas (marianadv) on 2015-05-25T18:33:38Z No. of bitstreams: 1 influencia_mata.pdf: 1564434 bytes, checksum: d4085766e9b3221648da1454a2d57cca (MD5) / Made available in DSpace on 2015-05-25T18:33:38Z (GMT). No. of bitstreams: 1 influencia_mata.pdf: 1564434 bytes, checksum: d4085766e9b3221648da1454a2d57cca (MD5) Previous issue date: 2012 / Nenhuma / A presença ou ausência da mata ciliar é um fator que pode afetar a qualidade e disponibilidade de itens alimentares para peixes. O objetivo do presente trabalho foi testar a hipótese de que a extensão lateral da mata ciliar influencia a riqueza, abundância e alimentação da fauna de peixes. A partir da análise do conteúdo estomacal de quatro espécies de peixes, Bryconamericus iheringii (Boulenger, 1887), Characidium pterostictum (Gomes, 1947), Heptapterus mustelinus (Valenciennes, 1835) e Rineloricara microlepidogaster (Regan, 1904), foi possível realizar as análises de seletividade alimentar a fim de identificar alguma diferença e/ou padrão de consumo entre as áreas com vegetação ciliar densa e vegetação ciliar escassa. Os resultados deixaram evidentes que existe uma seleção positiva do consumo dos peixes para invertebrados aquáticos. Porém, não foi possível detectar as diferenças entre os dois tratamentos de mata das dietas das espécies. Nenhuma das espécies consumiu mais do que 2% de material alóctone. A não captação da influência da mata ciliar sobre a dieta dos peixes pode ter sido um efeito da escala espacial em que o trabalho foi realizado. As propriedades químicas, hidráulicas, morfológicas, de substrato e das associações com as comunidades biológicas dos copos hídricos são delineadas por muitos fatores da paisagem, que operam em diferentes escalas temporais e espaciais. Estudos afirmam que quanto maior é o grau de degradação das bacias hidrográficas menor vai ser a explicação dos fatores internos dos arroios sobre as alterações das comunidades. Devido a isso, é de suma importância a determinação dos fatores e da escala de influência sobre a comunidade íctica para se obter sucesso em ações de conservação e reabilitação dos corpos hídricos. / The presence or absence of riparian forest is a factor that can influence the quality and availability of food items for fish. The aim of this work is to test the hypothesis if the lateral extension of the riparian forest influences the richness, abundance and diet of fish fauna. By analyzing the stomach content of four fish species Bryconamericus iheringii (Boulenger, 1887), Characidium pterostictum (Gomes, 1947), Heptapterus mustelinus (Valenciennes, 1835) e Rineloricara microlepidogaster (Regan, 1904), it was possible to study their feeding selectivity in order to identify differences and/or consumption patterns in areas with dense riparian vegetation and areas with spare vegetation. The results show evidence for a positive selection for aquatic invertebrates in the diet of fish. However it was not possible to detect differences in the consumption concerning the type of vegetation. No species consumed more than 2% of allochthone material. The failed capture of the influence of the riparian for est on the diet of fish may have been an effect of the spatial scale design at which the work was done. The chemical, hydraulic, morphologic, substrate and associated biologic communities characteristics of the stream are delineated by many landscape factors, which are constrained by different temporal and spatial scales. Studies affirm that the greater the degradation of the watershed, the less explicable will be the internal factors of streams on changes in the community. Therefore it is of utmost importance to determine factors and scales of influence for ictic communities to ensure success in conservation and rehabilitation of water bodies.

abstract: The dynamics of urban water use are characterized by spatial and temporal variability that is influenced by associated factors at different scales. Thus it is important to capture the relationship between urban water use and its determinants in a spatio-temporal framework in order to enhance understanding and management of urban water demand. This dissertation aims to contribute to understanding the spatio-temporal relationships between single-family residential (SFR) water use and its determinants in a desert city. The dissertation has three distinct papers to support this goal. In the first paper, I demonstrate that aggregated scale data can be reliably used to study the relationship between SFR water use and its determinants without leading to significant ecological fallacy. The usability of aggregated scale data facilitates scientific inquiry about SFR water use with more available aggregated scale data. The second paper advances understanding of the relationship between SFR water use and its associated factors by accounting for the spatial and temporal dependence in a panel data setting. The third paper of this dissertation studies the historical contingency, spatial heterogeneity, and spatial connectivity in the relationship of SFR water use and its determinants by comparing three different regression models. This dissertation demonstrates the importance and necessity of incorporating spatio-temporal components, such as scale, dependence, and heterogeneity, into SFR water use research. Spatial statistical models should be used to understand the effects of associated factors on water use and test the effectiveness of certain management policies since spatial effects probably will significantly influence the estimates if only non-spatial statistical models are used. Urban water demand management should pay attention to the spatial heterogeneity in predicting the future water demand to achieve more accurate estimates, and spatial statistical models provide a promising method to do this job. / Dissertation/Thesis / Ph.D. Sustainability 2013

Orientadores: Paulo Inácio de Knegt López de Prado, Emerson Monteiro Vieira / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-16T00:11:22Z (GMT). No. of bitstreams: 1 Paise_Gabriela_D.pdf: 1506226 bytes, checksum: 2321b37857a637b42de135349a06edea (MD5) Previous issue date: 2010 / Resumo : Os efeitos negativos da fragmentação de habitats sobre pequenos mamíferos são amplamente reconhecidos. Entretanto, a intensidade desses efeitos depende de diversos fatores como o padrão de fragmentação, a escala avaliada, a permeabilidade de diferentes tipos de matrizes e a plasticidade comportamental de diferentes grupos de espécies. Neste estudo avaliamos os efeitos da fragmentação, em uma paisagem extremamente fragmentada de Mata Atlântica, na comunidade de pequenos mamíferos (i) através do uso diferencial de habitats pela comunidade e por guildas de espécies que usam habitats florestais, áreas abertas ou ambos (generalistas); (ii) através dos padrões de utilização de micro-habitats; (iii) através da similaridade na utilização da paisagem, entre sexos e espécies generalistas de habitat, em diferentes escalas espaciais. Nós utilizamos armadilhas de intercepção e queda em seis sítios de amostragem, nos quais avaliamos cinco habitats: floresta com rio, floresta sem rio, borda de floresta, matriz de pasto com rio e matriz de pasto sem rio. Nós detectamos que o habitat mais antrópico e inóspito, a matriz sem rio, suportou menor abundância de espécies. As guildas de espécies responderam diferentemente aos habitats da paisagem. Houve menor tolerância das espécies florestais ao habitat matriz sem rio. Até mesmo as espécies generalistas sofrem os efeitos negativos da matriz sem rio, diminuindo em abundância. Um pequeno aumento na estrutura da vegetação, como observado nas matrizes ripárias, mitigam o efeito negativo da matriz, tornando a abundância, riqueza e diversidade da matriz com rio comparável aos habitats florestais. A riqueza e abundância das guildas de espécies associadas à macro-habitats foram em geral influenciadas pela estrutura da vegetação em escala de micro-habitats e revelam um alto grau de especificidade de micro e macro-habitat. Esta especificidade mostra que, mesmo em paisagens altamente fragmentadas e alteradas, não ocorre a invasão das áreas florestais pela guilda de espécies de áreas abertas e que guildas de espécies florestais são incapazes de utilizar micro-habitats extremamente modificados. Nossos resultados indicam que a similaridade na utilização da paisagem varia entre espécies e sexos, entre diferentes escalas espaciais e pode ser fortemente dependente do padrão de fragmentação. O manejo das paisagens fragmentadas requer a existência de matrizes permeáveis, como a matriz de pasto com rio, as quais poderão funcionar como habitats potenciais, diminuindo a divisão da paisagem e facilitando a manutenção da comunidade original na paisagem fragmentada. / Abstract: The negative effects of habitat fragmentation on small-mammals are widely recognized. Nevertheless, the intensity of these effects depend on multiple factors such as the pattern of fragmentation, the evaluated scale, the permeability of different types of matrices, and the behavioral plasticity of different groups of species. In this study, we evaluated the effects of fragmentation on the community of small-mammals in a severely fragmented landscape of Brazilian Atlantic forest (i) through the differential use of habitats by the small-mammal community and by small-mammal guilds that use forest habitats, open areas or both (generalists); (ii) through the patterns of utilization of micro-habitats by small-mammal guilds; (iii) through the similarity in the use of the landscape, between sexes and generalist species in different space scales. We used pitfall traps installed in six sites. In each site, we sampled five habitats: forest fragments with streams, forest fragments without streams, forest edge, pasture matrix with streams, and pasture matrix without streams. We have detected that the pasture matrix without streams harbored lower species abundance than all other landscape units. The guilds responded differently to the different landscape units. The pasture matrix without streams is inhospitable for forest species which, even for generalists, suffer their effect, decreasing in abundance. A slight increase in the complexity of the vegetation, as observed in riparian matrices, mitigates its negative effect, making the abundance, richness and diversity of matrices with streams comparable to forest habitats. The richness and the abundance of macro-habitat-related guilds were, in general, influenced by the complexity of vegetation into the micro-habitat's scale and revealed a high degree of specificities of the macro- and micro-habitats. This specificity shows that, even in highly fragmented and altered landscapes, the invasion of forest habitats by open-area dwellers does not occur and that the forest dwellers are incapable to use the severely altered micro-habitats. Our results also indicate that in highly fragmented landscapes, the similarity in the use of the landscape varies between species and sexes, among different space scales, and can be strongly dependent on the pattern of fragmentation. The management of fragmented landscapes requires the existence of permeable matrices, as the pasture matrix with stream, which may function as potential habitat, decreasing the division of the landscape and facilitating the maintenance of the original community in the fragmented landscape. / Doutorado / Ecologia / Doutor em Ecologia

The vegetation provides an ecological space for birds and its structure reflects the availability of this place and resources. What specific influence does the vegetation structure have on bird abundance and which vegetation parameters are the most essential for bird species are classic, but still topical questions. The aim of this work was to find an answer using a study focused on birds in floodplain forests and to determine whether microhabitat characteristics affect the distribution of bird species within a single habitat. The data of this work were collected by the point counting method in six floodplain forests of the Czech Republic and Slovakia and statistically evaluated using regression, correlation and redundancy analysis. The birds were observed on a larger and smaller spatial scale. It was also used the study of the saturation of the environment by bird species over time and for the first time the analysis of habitat photo documentation as an alternative way for describing the vegetation structure. Results show that the analysis of vegetation photographs can be used to explain and predict avian abundance and thus create a new suitable method for birds' studies. Some bird species such as the collared flycatcher (Ficedula albicollis) and the Eurasian blue tit (Cyanistes caeruleus) have...

L'humidité du sol est une variable climatique essentielle dont le suivi à l'échelle globale est possible grâce à des instruments micro-ondes à bord des satellites. La précision de ces estimations est validée par comparaison directe aux mesures au sol. Tandis que les estimations satellitaires ont des résolutions allant de 30 à 100 km, les capteurs in situ sont généralement représentatifs d'une zone de quelques centimètres (résolution ponctuelle). Cette différence entre l'échelle spatiale des estimations satellitaires et in situ impacte le processus de validation et les statistiques obtenues à un niveau qui n'est pas connu actuellement. Cette thèse vise à améliorer la connaissance de l'impact du changement d'échelle spatiale, ainsi qu'à fournir des méthodes d'évaluation de celle-ci applicables à toute zone de validation. Pour ce faire, la relation entre les échelles spatiales et temporelles a été étudiée. Des séries modélisées et mesurées sur des régions différentes du globe ont été décomposées en échelles de temps allant de 0,5 et 128 jours, en utilisant des transformées en ondelettes. La représentativité spatiale des mesures à résolution ponctuelle a ensuite été évaluée, par échelle de temps, avec 4 approches différentes : l'analyse de la stabilité temporelle, la triple colocation, le pourcentage de zones corrélées (CArea) et une nouvelle approche utilisant des corrélations basées sur des ondelettes (WCor). De plus, l'incertitude d'échantillonnage a été évaluée séparément avec des approches bootstrap et des simulations de Monte Carlo de séries à résolution ponctuelle. À l'issue de ces expériences, il y a été constaté que la moyenne des valeurs de représentativité spatiale obtenues tend à augmenter avec l'échelle de temps, mais aussi leur dispersion. Cela implique que certaines stations ont de vastes zones de représentativité à des échelles saisonnières, tandis que d'autres ne l'ont pas. Aux échelles sous-hebdomadaires, toutes les stations présentaient de très petites zones de représentativité. Enfin, l'impact de l'incertitude d'échantillonnage s'est avéré assez important dans les métriques de validation satellitaire. / Soil moisture is an essential climate variable that is globally monitored with the help of satellite borne microwave instruments. The accuracy of satellite soil moisture estimations is assessed by direct comparison to in situ measurements. While satellite estimates have a resolution ranging between 30 and 100 km, in situ sensors typically measure over an area of a few centimetres (point resolution). This spatial scale mismatch between satellite and in situ soil moisture estimates impairs the validation process and the respective summary statistics to an extent that is not currently known. This thesis aims at improving the knowledge of the spatial scale mismatch, as well as providing methods for its assessment applicable to any validation area. To this end, the connection between the SM spatial and time scales was investigated. Modelled and measured soil moisture series at different regions of the globe were decomposed into time scales ranging from 0.5 to 128 days, using wavelet transforms. The spatial representativeness of the point measurements was then assessed, on a per time scale basis, with 4 different approaches: temporal stability analysis, triple collocation, the percentage of correlated areas (CArea) and a new approach that uses wavelet- based correlations (WCor). Moreover, one of the components of the mismatch, the sampling uncertainty, has been assessed separately with bootstrap and Monte Carlo simulations of point-support series. It was found that the average of the spatial representativeness values tends to increase with the time scales but so does their dispersion. This implies that some stations had large representativeness areas at seasonal scales, while others do not. At sub-weekly scales, all stations exhibited very small representativeness areas. Finally, the sampling uncertainty has been observed to have a considerable impact on satellite validation statistics.

No description available.

Wildlife management and natural resource policy decisions are increasingly being made at the landscape level. Understanding the relationship between modification and the pattern of land classes may minimize potential impacts and enhance the complement of wildlife species. Twenty-four expressions were selected for landscape analysis that describe the spatial heterogeneity, fragmentation, edge characteristics, and connectivity of pattern. Metric relationships were characterized across a variety of landscapes. Cluster analysis organized the metrics into classes quite different from the classification categories used in the literature. Cluster membership reflected the number of land classes, the amount and distribution of forest cover, number of forest patches, patch position, patch shape, patch radius, and edge length. Cartographic modeling was used to determine how modification influenced landscape pattern. The models depicted spatial relationships resulting from proposed landscape changes. Timber harvest schemes with a few large units and those in clustered arrangements led to less fragmentation than those schemes with several small units or those dispersed across the landscape. The placement of roads had either an invasive or partitioning effect on landscape pattern. Discriminant analysis rated the effectiveness of pattern expressions for environmental assessment. Metric effectiveness differed among the timber harvest, road expansion, and deforestation modification schemes. The utility and limitations of each expression was discussed. Sensitivity analyses examined the effects of changing spatial scale on pattern description. Scale influence was dependent upon landscape complexity, distribution of land classes, and the size and shape of those classes. The loss of ability to detect localized variability, to differentiate among spatial patterns, and to represent boundary detail accompanied the use of large pixels (420m²). There was evidence that spatial scale influences habitat evaluation. Semivariogram analysis assessed the constancy of expression behavior during changes in scale and presented the limits of tolerance for using large pixels in pattern analyses. The variability observed suggested that pattern misrepresentation occurred at coarse resolution levels. The successful application of landscape analysis depends on the ability to quantify pattern. By analyzing and understanding selected aspects of landscape pattern, I have examined how wildlife management can be enhanced through a knowledge of the landscape. / Ph. D.

An ensemble representation refers to a statistical summary representation of a group of similar objects. Recent work has shown that we can form multiple ensemble representations – ensemble representations for a single feature dimension across multiple stimulus groups, ensemble representations for multiple feature dimensions in the same stimulus group, and ensemble representations across multiple sensory domains. In our study, we use hierarchical stimuli based on the Navon figures (Navon 1977) to study properties of ensemble representations across multiple spatial scales. In Experiments 1 and 3, we study properties of ensemble representations for the orientation and size feature dimension, respectively. In Experiment 2, we study properties of individual representations for the orientation feature dimension. Results indicate that it is possible to form ensemble representations across multiple spatial scales. Experiment 1 shows that the global ensemble representations may be extracted automatically (without intent) whereas the local ensemble representation is only extracted in response to task demands (with intent). Finally, in both Experiment 1 and Experiment 3, participants were more accurate at reporting the global ensemble representation than the local ensemble representation whereas in Experiment 2, performance did not differ across the levels. These results point towards global precedence in the formation of ensemble representations.