Múltiplos fatores determinam as interações entre espécies em redes ecológicas, tais como as barreiras nas suas morfologias, distribuições espaços-temporais, suas abundâncias relativas e histórias evolutivas. Novos métodos estão tornando possível avaliar a importância relativa desses fatores determinantes. Todavia a capacidade de avaliar a importância das histórias evolutivas das espécies é ainda limitada pela escassez de métodos que permitam incluir informações derivadas de filogenias independentes entre os preditores das interações. Esse estudo objetiva superar essa limitação através da inclusão das histórias evolutivas das espécies entre os potenciais determinantes das interações, permitindo a análise comparativa das suas importâncias como estruturadores das redes ecológicas. Usando conceitos dos campos de redes ecológicas e da ecofilogenia foram hipotetizados possíveis cenários filogenéticos preditores das frequências de interações. Para ilustrar o uso desses cenários foi usada a base de dados de uma rede beija-flor-planta da Mata Atlântica do sudeste brasileiro, e foram avaliadas as importâncias relativas das histórias evolutivas das espécies, suas abundâncias e acoplamentos nas suas morfologias e fenologias como determinantes das suas frequências de interações. Os resultados sugerem que as histórias evolutivas de beija-flores e plantas são mais importantes do que as suas abundâncias relativas em estruturar a rede, mas são menos importantes do que barreiras morfológicas e fenológicas. Com o uso de cenários filogenéticos, é oferecida uma extensão de um arcabouço conceitual e metodológico já amplamente utilizado por representar uma forma robusta e flexível de testar a importância de múltiplos fatores e suas combinações como determinantes das interações entre espécies em comunidades. / Multiple factors determine species interactions in ecological networks, such as morphological barriers, spatio-temporal distributions, relative species abundance and their evolutionary history. Novel methods are making it possible to evaluate the relative importance of each of these determinants factors. However, the lack of methods that allow us to incorporate information from independent phylogenies among the predictors of interactions limits our capacity of evaluating the relative importance of evolutionary histories. This work aims to overcome this limitation by including the evolutionary histories of species among the potential determinants of interactions, allowing the comparative analysis of its importance in structuring ecological networks. Different possible phylogenetic scenarios were hypothesized to predict frequencies of species interactions by combining concepts from the fields of ecological networks and ecophylogenetics. The usage of these scenarios is illustrated in a hummingbird-plant interaction network database from the Atlantic Forest in southeastern Brazil, in order to evaluate the relative importance of evolutionary histories of species, species relative abundances, and morphological and phenological barriers as determinants of species interactions frequencies. The results suggests that evolutionary histories of hummingbirds and plants are more important than their relative abundances in structuring their interaction network, but less important than morphological and phenological barriers. Phylogenetic scenarios usage offers an extension to a conceptual and methodological framework widely used by representing a robust and flexible way to evaluate the relative importance of multiple factors and their combinations as determinants of species interactions in communities.

Submitted by Sandra Pereira (srpereira@ufrrj.br) on 2016-10-03T11:27:04Z No. of bitstreams: 1 2011 - Renata Cristina de Souza Coelho.pdf: 1271616 bytes, checksum: 7e462a30d8cdde8325d226c9741f0141 (MD5) / Made available in DSpace on 2016-10-03T11:27:04Z (GMT). No. of bitstreams: 1 2011 - Renata Cristina de Souza Coelho.pdf: 1271616 bytes, checksum: 7e462a30d8cdde8325d226c9741f0141 (MD5) Previous issue date: 2011-05-02 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / In the Atlantic forest, deforestation and the resulting forest fragmentation have been worsening since the sixteenth century. Recent data estimate that the area covered with forest of Mata Atlantica represents between 11.6% and 16% of its original length, resulting in the extinction of species due to habitat reduction and isolation and edge effect. Among animals, insects are noted for presenting the largest number of species and participate in a large number of interactions with other organisms. Being good bioindicators in studies of environmental impact assessment, including the effects of forest fragmentation. Ant communities (Hymenoptera: Formicidae) have been used as bioindicators because of their high species richness and respond to environmental changes. The main objective was to study the effects of forest fragmentation on the richness, diversity and community composition of ants foraging on plants. Moreover, there was the spatial and temporal variations of this community and the influence of vegetation structure and in the richness and diversity of arboreal ant fauna. The study was conducted during the dry season of 2009 and the rainy season of 2010. We sampled eight forest fragments in the City of Vassouras, besides Tingu? Biological Reserve, State of Rio de Janeiro. In a plot of 120 m2, 20 trees with CAP between 15 to 40 cm were marked, these being distant about 10 m apart. The same amount of sardines in edible oil, was placed in the trunk of each tree and on white paper, 10 cm x 12 cm, distributed over 20 bushes near their trees, the approximate height of 1 m. The baits were placed in the schedule between 10:30 and 11:00, one hour remaining on the vegetation. To sample the vegetation structure, we used the method of touch. All trees with CAP over 5 cm were counted and morphospecies and were also obtained the percentage of canopy cover. In order to study the influence of abiotic factors were recorded temperature and relative humidity. We collected a total of 73 morphospecies of ants distributed in 20 genera and six subfamilies, Myrmicinae (33), Dolichoderinae (15), Formicinae (12), Pseudomyrmecinae (7), Ponerinae (3), Ectatomminae (2) and Ecitoninae (1). Pheidole was the largest genus with species richness (13), followed by Linepithema (9) Solenopsis (8), Pseudomyrmex (7) and Brachymyrmex (6). Overall, the diversity index and species richness of ants were higher in the rainy season than in dry season. We found 12 unique species in the dry season and 32 in the rainy season. The variation of fragment size did not influence the species richness of ants on a local scale. The multiple regression analysis step by step to the data of vegetation structure of the fragments revealed that the richness and diversity (H') of ant species depended mainly on the density of shrubs and trees away all the vegetation structure has influenced ant community. This shows that for the arboreal ant community, the habitat quality is more important than the size of the area, stressing the importance of conservation of the Atlantic. / No bioma Mata Atl?ntica, o desmatamento e o consequente processo de fragmenta??o florestal v?m se agravando desde o s?culo XVI. Dados recentes estimam que a ?rea coberta com remanescentes florestais de Mata Atl?ntica representa entre 11,6% a 16% de sua extens?o original, tendo como consequ?ncia a extin??o de esp?cies, devido ? diminui??o e isolamento dos h?bitats e ao efeito de borda. Dentre os animais, os insetos se destacam por apresentarem o maior n?mero de esp?cies e participarem de um grande n?mero de intera??es com outros organismos. Sendo bons bioindicadores em estudos de avalia??o de impactos ambientais, incluindo os efeitos da fragmenta??o florestal. Comunidades de formigas (Hymenoptera: Formicidae) t?m sido utilizadas como bioindicadoras em fun??o de sua elevada riqueza de esp?cies e por responderem a mudan?as no ambiente. O principal objetivo deste trabalho foi estudar os efeitos da fragmenta??o florestal sobre a riqueza, a diversidade e a composi??o das comunidades de formigas que forrageiam sobre plantas. Al?m disso, verificou-se as varia??es espaciais e temporais desta comunidade e a influ?ncia da estrutura da vegeta??o e sob a riqueza e diversidade da mirmecofauna arbor?cola. O estudo foi realizado durante a esta??o seca de 2009 e a esta??o chuvosa de 2010. Foram amostrados oito fragmentos florestais do Munic?pio de Vassouras, al?m da Reserva Biol?gica do Tingu?, no Estado do Rio de Janeiro. Em uma parcela de 120 m2, 20 ?rvores com CAP entre 15 a 40 cm foram marcadas, estando estas distantes em cerca de 10 m entre si. Uma mesma quantidade de sardinha, em ?leo comest?vel, foi colocada no tronco de cada uma das ?rvores e sobre papel branco, com 10 cm x 12 cm, distribu?das sobre 20 arbustos, pr?ximos das respectivas ?rvores, a altura aproximada de 1 m. As iscas foram colocadas no hor?rio entre 10:30h e 11:00h, permanecendo 1 hora sobre a vegeta??o. Para estudar a estrutura da vegeta??o, foi utilizado o m?todo do toque. Todas as ?rvores com CAP acima de 5 cm foram contadas e morfoespeciadas e tamb?m foram obtidas a porcentagem de cobertura do dossel. A fim de estudar a influ?ncia dos fatores abi?ticos, foram registradas, com termohigr?metro, a temperatura e a umidade relativa do ar. Foi coletado um total de 73 morfoesp?cies de formigas distribu?das em 20 g?neros e seis subfam?lias: Myrmicinae (33), Dolichoderinae (15), Formicinae (12), Pseudomyrmecinae (7), Ponerinae (3), Ectatomminae (2) e Ecitoninae (1). Pheidole foi o g?nero com maior riqueza de esp?cies (13), seguido de Linepithema (9) Solenopsis (8), Pseudomyrmex (7) e Brachymyrmex (6). No geral, o ?ndice de diversidade e a riqueza de esp?cies de formigas foram maiores na esta??o chuvosa que na esta??o seca. Foram encontradas 12 esp?cies exclusivas na esta??o seca e 32 na esta??o chuvosa. A varia??o de tamanho dos fragmentos n?o influenciou a riqueza de esp?cies de formigas numa escala local. As an?lises de regress?o m?ltipla passo a passo para os dados da estrutura da vegeta??o dos fragmentos revelaram que a riqueza e a diversidade (H?) de esp?cies de formigas dependeram, principalmente, da densidade de arbustos e ?rvores. Isto mostra que para a comunidade de formigas arbor?colas, a qualidade do h?bitat ? mais importante do que o tamanho da ?rea, ressaltando a import?ncia do estado de conserva??o dos fragmentos para a prote??o da biodiversidade da Mata Atl?ntica

Adults associate their childhood with playing outdoors, often in natural settings. This type of free play is valuable to child development. Children tend to use outdoor play areas in physically active ways, and time spent outdoors relates positively to increased physical activity in children. However, children today are spending an increasing amount of time indoors rather than outdoors. Recent research has shown that the amount of time children spend in outdoor play is directly related to parental concerns about their children's exposure to outdoor hazards. The purpose of this project was to investigate the relationship between parental attitude toward nature and the development of fine and gross motor skills in young children. The sample for this study was drawn from parents of children ages 3 to 5 years old enrolled at one of two University Child Development Centers. The assessment tool used was composed of sections that ask parents about their attitudes toward nature, about their young children spending time outdoors, how much time their children actually spend in outdoor and indoor activities, and standard demographic questions. The childcare centers independently assessed d correlations and ANOVA. Results from this study indicated that parents had positive views toward nature and towards their child's recreation. Children who participated in certain indoor activities tended to score higher in the area of fine motor skills. However, children who spent more time indoors in free play had lower gross motor skill scores. Parents who scored better on the Parental Attitude toward Their Child's Outdoor Recreation scale reported that their child spent more time in outdoor free play and outdoor organized sports and activities. Parents preferred outdoor play spaces when compared to indoor play spaces and specifically those outdoor spaces that were constructed with more nearby natural components.

Múltiplos fatores determinam as interações entre espécies em redes ecológicas, tais como as barreiras nas suas morfologias, distribuições espaços-temporais, suas abundâncias relativas e histórias evolutivas. Novos métodos estão tornando possível avaliar a importância relativa desses fatores determinantes. Todavia a capacidade de avaliar a importância das histórias evolutivas das espécies é ainda limitada pela escassez de métodos que permitam incluir informações derivadas de filogenias independentes entre os preditores das interações. Esse estudo objetiva superar essa limitação através da inclusão das histórias evolutivas das espécies entre os potenciais determinantes das interações, permitindo a análise comparativa das suas importâncias como estruturadores das redes ecológicas. Usando conceitos dos campos de redes ecológicas e da ecofilogenia foram hipotetizados possíveis cenários filogenéticos preditores das frequências de interações. Para ilustrar o uso desses cenários foi usada a base de dados de uma rede beija-flor-planta da Mata Atlântica do sudeste brasileiro, e foram avaliadas as importâncias relativas das histórias evolutivas das espécies, suas abundâncias e acoplamentos nas suas morfologias e fenologias como determinantes das suas frequências de interações. Os resultados sugerem que as histórias evolutivas de beija-flores e plantas são mais importantes do que as suas abundâncias relativas em estruturar a rede, mas são menos importantes do que barreiras morfológicas e fenológicas. Com o uso de cenários filogenéticos, é oferecida uma extensão de um arcabouço conceitual e metodológico já amplamente utilizado por representar uma forma robusta e flexível de testar a importância de múltiplos fatores e suas combinações como determinantes das interações entre espécies em comunidades. / Multiple factors determine species interactions in ecological networks, such as morphological barriers, spatio-temporal distributions, relative species abundance and their evolutionary history. Novel methods are making it possible to evaluate the relative importance of each of these determinants factors. However, the lack of methods that allow us to incorporate information from independent phylogenies among the predictors of interactions limits our capacity of evaluating the relative importance of evolutionary histories. This work aims to overcome this limitation by including the evolutionary histories of species among the potential determinants of interactions, allowing the comparative analysis of its importance in structuring ecological networks. Different possible phylogenetic scenarios were hypothesized to predict frequencies of species interactions by combining concepts from the fields of ecological networks and ecophylogenetics. The usage of these scenarios is illustrated in a hummingbird-plant interaction network database from the Atlantic Forest in southeastern Brazil, in order to evaluate the relative importance of evolutionary histories of species, species relative abundances, and morphological and phenological barriers as determinants of species interactions frequencies. The results suggests that evolutionary histories of hummingbirds and plants are more important than their relative abundances in structuring their interaction network, but less important than morphological and phenological barriers. Phylogenetic scenarios usage offers an extension to a conceptual and methodological framework widely used by representing a robust and flexible way to evaluate the relative importance of multiple factors and their combinations as determinants of species interactions in communities.

Múltiplos fatores determinam as interações entre espécies em redes ecológicas, tais como as barreiras nas suas morfologias, distribuições espaços-temporais, suas abundâncias relativas e histórias evolutivas. Novos métodos estão tornando possível avaliar a importância relativa desses fatores determinantes. Todavia a capacidade de avaliar a importância das histórias evolutivas das espécies é ainda limitada pela escassez de métodos que permitam incluir informações derivadas de filogenias independentes entre os preditores das interações. Esse estudo objetiva superar essa limitação através da inclusão das histórias evolutivas das espécies entre os potenciais determinantes das interações, permitindo a análise comparativa das suas importâncias como estruturadores das redes ecológicas. Usando conceitos dos campos de redes ecológicas e da ecofilogenia foram hipotetizados possíveis cenários filogenéticos preditores das frequências de interações. Para ilustrar o uso desses cenários foi usada a base de dados de uma rede beija-flor-planta da Mata Atlântica do sudeste brasileiro, e foram avaliadas as importâncias relativas das histórias evolutivas das espécies, suas abundâncias e acoplamentos nas suas morfologias e fenologias como determinantes das suas frequências de interações. Os resultados sugerem que as histórias evolutivas de beija-flores e plantas são mais importantes do que as suas abundâncias relativas em estruturar a rede, mas são menos importantes do que barreiras morfológicas e fenológicas. Com o uso de cenários filogenéticos, é oferecida uma extensão de um arcabouço conceitual e metodológico já amplamente utilizado por representar uma forma robusta e flexível de testar a importância de múltiplos fatores e suas combinações como determinantes das interações entre espécies em comunidades. / Multiple factors determine species interactions in ecological networks, such as morphological barriers, spatio-temporal distributions, relative species abundance and their evolutionary history. Novel methods are making it possible to evaluate the relative importance of each of these determinants factors. However, the lack of methods that allow us to incorporate information from independent phylogenies among the predictors of interactions limits our capacity of evaluating the relative importance of evolutionary histories. This work aims to overcome this limitation by including the evolutionary histories of species among the potential determinants of interactions, allowing the comparative analysis of its importance in structuring ecological networks. Different possible phylogenetic scenarios were hypothesized to predict frequencies of species interactions by combining concepts from the fields of ecological networks and ecophylogenetics. The usage of these scenarios is illustrated in a hummingbird-plant interaction network database from the Atlantic Forest in southeastern Brazil, in order to evaluate the relative importance of evolutionary histories of species, species relative abundances, and morphological and phenological barriers as determinants of species interactions frequencies. The results suggests that evolutionary histories of hummingbirds and plants are more important than their relative abundances in structuring their interaction network, but less important than morphological and phenological barriers. Phylogenetic scenarios usage offers an extension to a conceptual and methodological framework widely used by representing a robust and flexible way to evaluate the relative importance of multiple factors and their combinations as determinants of species interactions in communities.

Em resposta aos danos ocasionados por insetos, as plantas emitem voláteis que atraem os inimigos naturais desses herbívoros. Embora essa relação tritrófica venha sendo intensamente estudada, muitos mecanismos envolvidos nesta interação ainda permanecem inexplorados. Dentre os compostos voláteis induzidos por herbivoria e emitidos pelas plantas, os terpenos são os mais expressivos e abundantes. Em resposta ao dano ocasionado por um inseto, cascatas bioquímicas são iniciadas na planta, as quais podem alterar a expressão de genes envolvidos na resposta a tal dano. Este trabalho analisou as mudanças na expressão gênica e produção de compostos voláteis em plantas de milho, Zea mays (Poaceae)promovidas por lagartas Spodoptera frugiperda (Lepidoptera: Noctuidae) ao longo do tempo. Utilizando a técnica de PCR em tempo real (qRTPCR) foram verificadas respostas no nível da expressão gênica das plantas submetidas à indução por herbivoria. Foram analisados os genes de uma lipoxigenase e de três terpeno sintases, enzimas envolvidas na produção de compostos voláteis que atraem parasitóides de S. frugiperda. As plantas submetidas à herbivoria apresentaram níveis de expressão gênica e emissão de voláteis maiores do que as plantas sadias. Os resultados fornecem bases para o entendimento dos mecanismos endógenos responsáveis pela liberação de voláteis nas plantas visando o estabelecimento de novos fundamentos para o controle biológico de pragas. / In response to insect damage, plants emit volatiles that attract natural enemies of herbivores. Although this tritrophic interaction has been intensively studied, many mechanisms involved in this interaction remain unexplored. Among the herbivore-induced volatile compounds, terpenes are the most abundant and significant ones. In response to insect damage, biochemical pathways are activated, which can alter the expression of genes involved in the response to that damage. This study examined changes in gene expression and volatile compounds production in maize plants, Zea mays (Poaceae) promoted by Spodoptera frugiperda (Lep.: Noctuidae) caterpillars through time. Using the real-time PCR technique (qRT-PCR) we verified responses on the level of gene expression of plants subjected to herbivores feeding. We analyzed genes of lipoxygenase and three terpene synthases, enzymes involved in the synthesis of volatile compounds that attract parasitoids of S. frugiperda. Plants subjected to herbivory had higher levels of gene expression and volatile emission when compared to healthy plants. Results provide basis for better understanding of plant volatile emission endogenous mechanisms in order to set new foundations for biological control of pests.

Au sein des communautés végétales, les traits fonctionnels dirigent et influencent les processus sol-plantes. Le ruissellement et l'érosion concentrés, causes principales de la dégradation des sols, peuvent être contrôlés par des végétations herbacées qui créent une rugosité hydraulique induisant la réduction de la vitesse des flux de ruissellement et la rétention des sédiments. L'approche des traits, plutôt que taxonomique, permet de comprendre et caractériser les effets directs de la végétation sur le ruissellement et la rétention des sédiments. Ce projet de recherche vise à approfondir les connaissances vis-à-vis des effets (i) des traits fonctionnels (Chapitre 1), (ii) de la complémentarité des traits (Chapitre 2), et (iii) de la diversité fonctionnelle (Chapitre 3) sur les écoulements concentrés et la rétention des sédiments afin d'évaluer l'efficacité et le design de haies herbacées pour réduire les impacts de l'érosion des sols dans les bassins versants limoneux d'Europe. Parmi les combinaisons de traits principaux identifiées comme augmentant la rugosité hydraulique (densité et diamètre des tiges, et densité et surface foliaire), certains traits sont négativement corrélés. Un meilleur effet pourrait donc être atteint au sein d'assemblage d'espèces par un effet complémentaire des traits. Cependant, des effets non-additifs des diversités en espèces et fonctionnelle ont été trouvés, chacun généré par un effet dominant des traits dans les communautés testées. Ces effets des traits et de la diversité fonctionnelle sur la rugosité hydraulique et la rétention des sédiments constituent une nouvelle avancée dans la compréhension des effets de l'assemblage des traits sur les processus d'écoulement et d'érosion des sols ainsi qu'une base pour le design et la modélisation des haies herbacées pour le contrôle du ruissellement et de l'érosion. / Plant-soil processes are driven and influenced by plant functional traits in vegetation communities. Concentrated runoff and erosion constitute the main cause of soil degradation and can be managed by herbaceous vegetation creating hydraulic roughness that induces flow velocity reduction and sediment retention. Using plant trait-based approach, unlike taxonomical approach, allows to understand and characterise the direct effects of the vegetation on runoff and sediment retention. This research project aims to deepen the knowledge regarding the effects of (i) plant functional traits (chapter 1), (ii) traits' complementarity (chapter 2) and (iii) functional diversity (chapter 3) on concentrated runoff and sediment retention processes, in order to evaluate the efficiency and design of herbaceous hedges to reduce the impacts of soil erosion in loamy European agricultural catchments. The identification of the main efficient traits and traits' combinations towards hydraulic roughness increase (stem density, diameter, leaf area and density) highlighted negatively correlated traits, suggesting that a trade-off could be reached within a plant species assemblage through a complementarity effect of the traits. However, non-additive effects of plant species diversity and functional diversity were found, both driven by dominant traits in the community. The effects of traits and functional diversity on the hydraulic roughness and sediment retention constitute a new advance in the understanding of plant trait assemblage on runoff and soil erosion processes and a baseline for the design and modelling of herbaceous hedges for runoff and erosion control.

Premise of research. The duration and intensity of flowering overlap among plants are the first determiners of the potential for pollinator-mediated plant-plant interactions. Yet, our ability to describe community-wide patterns of coflowering, and thus understand its impact on the structure of plant-pollinator communities, is limited. Methodology. We present a conceptual framework for how network theory can reveal structural properties that are ecologically relevant in diverse coflowering communities. Coflowering modules, in particular, may suggest that groups of species coflower more strongly (clustering) with each other than with other species (over-dispersion) in the community. Such a finding would indicate that competitive and facilitative interactions do not act alone but instead act simultaneously to mediate the assembly of coflowering communities. We illustrate our conceptual framework in four diverse coflowering communities in the serpentine seeps in northern California. Pivotal results. Our coflowering networks vary in size and degree but not in overall connectance, suggesting that both intrinsic community features (species richness) and ecological constraints (length of flowering season) play a role in mediating coflowering community structure (distribution of frequency and intensity of flowering overlap among plant species). We show, for the first time, that groups of species tend to coflower more strongly with each other than with other species in a community, supporting the idea that competition and facilitation are not mutually exclusive processes mediating coflowering community assembly. Our results show that the degree of modularity is not sensitive to the number of coflowering species within each community, suggesting that ecological factors may be more important in driving this pattern. Conclusions. Coflowering networks have the potential to advance our understanding of the causes and consequences of flowering overlap in diverse plant communities by revealing a more in-depth and novel characterization of coflowering community structure. Such characterization will allow for a better understanding of the importance of coflowering patterns in mediating the structure of plant-pollinator interactions.

Thesis (PhD (Conservation Ecology and Entomology))--Stellenbosch University, 2008. / ENGLISH ABSTRACT: Shifts in species ranges are an important consequence of climate change, and can affect the composition, structure and functioning of ecosystems. Generally, in response to rising temperatures, species have increased their altitudinal and latitudinal distributions along their cooler boundaries, although there has been large variation between species. However, in addition to climatic factors, species range limits are also sensitive to biotic interactions. Therefore, interspecific interactions may be able to influence the impact of climate change on species distributions. In this thesis climate change, range shifts and spatial variation in plant-plant interactions are documented to examine the potential for biotic interactions to mediate climate-driven altitudinal range shifts on sub-Antarctic Marion Island. The climate on Marion Island changed considerably between 1949 and 2003, with significant trends in biologically-relevant parameters encompassing average climatic conditions, variability in climate parameters and extreme weather events. Combining these trends showed that while environmental conditions have ameliorated for some species, they have become more abiotically stressful for others (e.g. hygrophilous species). Concurrent with changes in the island’s climate, there have been rapid changes in the elevational distribution of Marion Island’s native vascular flora. On average species ranges expanded upslope (as predicted in response to the warming experienced on the island), although individual range expansion rates varied greatly. As a result of the idiosyncratic expansion rates, altitudinal patterns of species richness and community composition changed considerably. Therefore, both speciesand community-level changes occurred in the flora of Marion Island, demonstrating the community’s sensitivity to climate change. To determine the potential for interspecific interactions to have mediated these changes in species elevational ranges, spatial variation in the balance of positive and negative plant-plant interactions were examined. Increasing spatial association between four dominant species along an altitudinal severity gradient suggested that the intensity of facilitation, relative to the intensity of competition, is greater under more severe conditions. While, interaction strength varied between species pairs, the nature of relationship was consistent across the species. At a broader spatial scale, the performance of the grass Agrostis magellanica was compared in the presence and in the absence of the cushion plant Azorella selago along the entire altitudinal range of both species. The influence of the cushion plant on A. magellanica switched from negative to positive with increasing environmental severity, reaching a positive asymptote under extreme environmental conditions. Therefore, on Marion Island the spatial variation in the nature of biotic interactions is related to environmental severity, and facilitative interactions can be strong under extreme environmental conditions. These results show that positive biotic interactions are important at higher elevations on Marion Island, and could thus accelerate upslope range expansions in response to climate change. Nonetheless, competitive inhibition of upslope species movement, especially in areas of dense vegetation (i.e. mid or low altitudes), could have the opposite result, acting antagonistically with the effect of rising temperatures. This research highlights the importance of considering interspecific interactions when examining the biotic implications of climate change, both for affecting the rate at which species ranges change and the extent of species distributions. / AFRIKAANSE OPSOMMING: Die verskuiwing van spesies se verspreidingspatrone is ‘n belangrike gevolg van klimaatsverandering en kan die samestelling, struktuur en funksionering van ekosisteme affekteer. Oor die algemeen, in reaksie op verwarming, kom spesies op hoër hoogtes bo seespieël en hoër breedtegrade voor, alhoewel daar groot verskille tussen spesies in hierdie aspek is. Behalwe vir klimatologiese faktore, is spesies se verspreidingslimiete ook sensitief vir biotiese interaksies met ander spesies. Daarom kan interaksies tussen spesies die effek van klimaatsverandering op spesiesverspreiding verder beïnvloed. In hierdie verhandeling word klimaatsverandering, verandering in verspreiding van spesies en geografiese variasie in plant-plant interaksies ondersoek. Dit word gedoen ten einde die moontlikheid te toets dat biotiese interaksies die verandering in verspreidingspatrone van klimaat gedrewe spesies op sub-Antarktiese Marion Eiland beïnvloed. Marion Eiland se klimaat het aansienlik tussen 1949 en 2003 verander, met betekenisvolle neigings in biologies-relevante parameters, insluitend gemiddelde klimaatstoestande, variasie in klimaat en uiterste weerstoestande. As die veranderinge saam beskou word, wys dit dat, terwyl omgewingstoestande vir sommige spesies verbeter het, toestande vir ander spesies abioties meer ongunstig geword het (bv. akwatiese plantsoorte). Tesame met die veranderinge in die eiland se klimaat, het die hoogte bo seespieël verspreiding van Marion Eiland se inheemse vaatplante vinnig verander. Gemiddeld het spesies-verspreiding se hoogte bo seespieël na hoër hoogtes verskuif (soos voorspel in reaksie op verwarming), alhoewel die tempo van verskuiwing na hoër hoogtes tussen spesies verskil het. As gevolg van hierdie idiosinkratiese reaksies, het die aantal en samestelling van plant spesies op verskillende hoogtes op die eiland aansienlik verander. Die sensitiwiteit van Marion Eiland se flora ten opsigte van klimaatsverandering word deur hierdie verandering gedemonstreer. Om te bepaal of die interaksies tussen spesies verspreidingspatrone kan beïnvloed, is die geografiese variasie in die balans van positiewe en negatiewe interaksies ondersoek. Vier dominante vaatplante het meer geassosieerd geraak hoe hoër hulle bo seespieël voorgekom het. Dit is ‘n aanduiding dat die sterkte van die positiewe interaksies (fasilitering), relatief tot die sterkte van die negatiewe reaksie (kompetisie), groter onder uiterste omgewingstoestande is. Die sterkte van die interaksie het verskil tussen spesies pare, maar die verhouding tussen omgewingstoestande en die sterkte van die interaksie was dieselfde vir alle spesies. Op ‘n breër geografiese vlak is die opbrengs van die gras Agrostis magellanica in die teenwoordigheid en afwesigheid van die polsterplant Azorella selago op alle hoogtes waar die plante saam voorkom vergelyk. Die invloed van A. selago op A. magellanica was negatief op lae hoogtes bo seespieël, maar het meer positief geraak met ‘n toename in hoogte bo seespieël, tesame met omgewingshardheid. Die invloed van die polsterplant op die gras het ‘n positiewe asimptoot onder uiterste omgewingstoestande bereik. Dus, op Marion Eiland is die geografiese variasie in biotiese interaksies verwant aan omgewingstoestande, en positiewe interaksies kan selfs onder die uiterste omgewingstoestande sterk wees. Hierdie resultate wys dat positiewe biotiese interaksies tussen plante belangrik is by hoër hoogtes bo seespieël op Marion Eiland. Die interaksies kan dus die opwaartse verspreiding van spesies in reaksie op klimaatsverandering versnel. Nogtans kan negatiewe interaksies die teenoorgestelde effek hê aangesien kompetisie tussen plante, veral in plekke met digte plantegroei (d.w.s. lae of middel hoogtes bo seespieël) opwaartse verskuiwing van spesies kan verhinder. Hierdie navorsing dui aan hoe belangrik dit is om interaksies tussen spesies in ag te neem, aangesien die interaksies die tempo en omvang van veranderinge in verspreiding kan beïnvloed.

Entomopathogenic fungi (EPF) of the genera Metarhizium and Beauveria are able to endophytically colonize a wide variety of plant species, providing protection against arthropod pests; besides increasing the plant development; and act as phytopathogen antagonists. The main objective of the present project was to evaluate the potential of entomopathogenic fungi as plant inoculants against the two-spotted spider mite Tetranychus urticae and the effects on plant growth promotion. Tritrophic effects were also studied, by evaluating prey consumption and feeding behavior of the predatory mite Phytoseiulus persimilis. The evaluated strategy has several potential benefits compared to the sole use of EPF as contact biocontrol agents, as it may control both pests and phytopathogens; be compatible with other natural enemies; provide limited exposure of fungal propagules to adverse environmental conditions, and accelerate seed emergence and plant growth. Considering this, the effects of seed inoculation using two isolates of Metarhizium robertsii and Beauveria bassiana were evaluated at University of Copenhagen, Denmark, on plant development (i.e. biomass and yield) and T. urticae population growth in a model system with bean plants under greenhouse conditions. Effects on feeding performance of P. persimilis were also studied in laboratory conditions. In Brazil, inoculation studies with EPF were conducted at ESALQ/USP with strawberry plants in greenhouse conditions and in the field in four commercial production areas of strawberries in Atibaia-SP and Senador Amaral-MG. In greenhouse studies, the effects of 15 isolates of Metarhizium spp., 5 isolates of B. bassiana and 5 of Cordyceps (= Isaria) fumosorosea were studied, whereas in the commercial area one isolate of Metarhizium and Beauveria was used. Strawberry roots were inoculated by submersion in fungal suspensions, and the population growth of spider mites, while plants development was assessed by measuring root lengths, biomass of roots and leaves, and the strawberry fruit weight. The results showed a significant reduction in T. urticae population and in general better plant development in both crops. The production of string beans and strawberry fruits were higher in inoculated plants than in non-inoculated plants. There was no difference in predation rate and feeding behavior of the predator mite P. persimilis towards T. urticae from fungal inoculated and uninoculated plants. In the commercial strawberry production areas there were significantly lower populations of T. urticae and fewer symptoms of plant diseases on plants in the fungal treated beds compared to plants in untreated beds. The results of this project bring a new perspective on the use of Metarhizium and Beauveria as plant protecting agents revealing that the use of entomopathogenic fungi as plant inoculants may be a promising strategy. / Fungos entomopatogênicos dos gêneros Metarhizium e Beauveria são capazes de colonizar endofiticamente uma ampla variedade de espécies de plantas e conferir à estas, proteção contra artrópodes pragas; além de acelerar o seu desenvolvimento; e atuar como antagonistas de fitopatógenos. O objetivo geral deste projeto foi avaliar o potencial de fungos entomopatogênicos como inoculantes contra o ácaro rajado Tetranychus urticae e seus efeitos na promoção de crescimento de plantas. O efeito tri-trófico no consumo e comportamento alimentar do ácaro predador Phytoseiulus persimilis também foi estudado. A estratégia avaliada traz vários potenciais benefícios comparado ao uso exclusivo de fungos entomopatogênicos como agentes de controle biológico de contato, como o controle duplo de pragas e fitopatógenos; compatibilidade com outros inimigos naturais; menor exposição de propágulos às condições ambientais adversas, além de acelerar a emergência de sementes e o crescimento de plantas. Diante disso, os efeitos da inoculação de sementes usando dois isolados de Metarhizium robertsii e Beauveria bassiana foram avaliados na Universidade de Copenhagen, Dinamarca, na promoção de crescimento das plantas (biomassa e produção) e no crescimento populacional de T. urticae em um sistema modelo com plantas de feijão em casa-de-vegetação. Efeitos no comportamento alimentar de P. persimilis foram também estudados em condições de laboratório. No Brasil, estudos foram conduzidos na ESALQ/USP com plantas de morangueiro em casa-de-vegetação e em quatro áreas de produção comercial de morangueiro em Atibaia-SP e Senador Amaral-MG. Nos estudos em casa-de-vegetação, os efeitos de 15 isolados de Metarhizium spp., 5 de B. bassiana e 5 de Cordyceps (= Isaria) fumosorosea foram estudados, enquanto em área comercial um isolado de Metarhizium e Beauveria foram utilizados. Raízes de morangueiro foram inoculadas por imersão em suspensões fúngicas, e foram avaliados o crescimento populacional do ácaro rajado e o desenvolvimento das plantas, quantificando o comprimento de raiz, biomassa de raiz e de parte aérea, e massa de frutos de morango. Os resultados mostraram redução significativa na população de T. urticae e em geral melhor desenvolvimento das plantas nas duas culturas. A produção de vagens em plantas de feijão e de frutos de morango foram superiores nas plantas inoculadas em relação às não inoculadas. Não se observou diferenças na taxa de predação e comportamento alimentar do ácaro predador P. persimilis quando oferecidos T. urticae provenientes de plantas inoculadas e não inoculadas. Em campo foram observadas populações significativamente menores de T. urticae e menos sintomas de doenças nas plantas inoculadas com os fungos, comparado às plantas não inoculadas. Os resultados obtidos por este projeto trazem uma nova perspectiva do uso de Metarhizium e Beauveria como agentes protetores de plantas revelando que a utilização de fungos entomopatogênicos como inoculantes pode ser uma estratégia promissora.