Considerando a importância das árvores por proporcionar o embelezamento das cidades, a amenização da temperatura local e entre outros fatores, se faz necessário conhecer as espécies que compõem a arborização urbana, o qual pode ser avaliada através do inventário. Após o levantamento florístico é possível medir a qualidade da arborização através de índices de riqueza e/ou índices espaciais das árvores em via pública. Baseado nisso, este estudo teve o objetivo de estudar a arborização urbana em duas regiões centrais da cidade Imperatriz – MA, avaliando riqueza, dominância, equidade e os índices espaciais. Para isso foi feito um inventário total dos indivíduos arbóreos, no qual contemplou-se altura das árvores ≥ 1,5 m, circunferência a altura do peito – CAP, raios e altura da copa, altura da 1ª bifurcação e também dados da malha urbana (largura e comprimento da calçada e vias, distância da árvore para o meio fio, dimensões da área de livre crescimento, altura de fiação e distância entre árvores). Todos os dados coletados foram inseridos em planilhas do programa Microsoft Office Excel onde foram calculados os índices de riqueza: Shannon-Weaver (H’), Odum, Menhinick (Dmn) e Jentsch (QM), índices de diversidade; Simpson (D) McIntosh (dominância); Pielou (J) e Bulla (E) (equidade) e os índices espaciais: ICA, IPO, Déficit, ICV, IDA, IAQC, PCV, IAVT, IAVPB, IAVPV, AVB, IPT, IPE, Sad, Npot e dfut. No estudo obteve-se um total de 228 quadras inventariadas, sendo 145 quadras pertencentes à Zona Central (ZC) e 83 a Zona Residencial Central (ZRC). Foram inventariados 2321 indivíduos distribuídos em 69 espécies e 27 famílias botânicas. Verificou-se também que na área total foram encontradas 24 espécies de origem nativas e 45 exóticas. Através da caracterização florística, observou-se que Licania tomentosa (Benth.) Fritsch e Azadirachta indica A. Juss são as espécies mais frequentes os quais representam 63,77% dos indivíduos. Os índices de riqueza demonstram baixa diversidade de espécies (H’, Dmn e QM), com exceção do índice de Odum. Os índices de dominância evidenciam a baixa diversidade, mostrando que existe alta dominância de poucas espécies. E os índices de equidade mostram haver baixa uniformidade do número de árvores para o número de espécies. No geral, a ZRC demonstrou ser menos diversa, com maior dominância e menor equidade. Quanto aos índices espaciais os resultados demonstram que a ocupação das copas em relação à área de calçadas está abaixo do recomendado, tanto para área total (19,81%) quanto para ZC (25,11%) e ZRC (16,93%), representando um déficit total de 7570 árvores, que representam percentualmente 76,5% de implantação de indivíduos para que houvesse ocupação completa.Quanto à relação do número de habitantes, a arborização de vias e praças de Imperatriz também se encontra inadequada, demonstrada pelo ICV (1,03 m²/habitante), IAVT e IAVPV (0,70 m²/habitante). Portanto, é possível perceber que a área de estudo em Imperatriz possui baixa diversidade, com poucos indivíduos em relação ao número de espécies, demonstra ainda haver desproporção entre a quantidade de árvores por espécie. Por outro lado, a área de estudo apresenta potencial para receber plantio de novas árvores desde que haja planejamento adequado por meio de um plano diretor de arborização urbana. / Considering the importance of trees for providing the beautification of cities, the amelioration of the local temperature and other factors, it is necessary to know the species that make up the urban forestry, which can be assessed through the inventory. After the floristic survey it is possible to measure the quality of the afforestation through indices of wealth and / or spatial indexes of the trees on public roads. Based on this, this study aimed to study the urban forestation in two central regions of the city Imperatriz - MA, evaluating wealth, dominance, equity and spatial indices. To this was done a total inventory of individual trees, which is included tree height ≥ 1.5 m, diameter at breast height - CAP rays and height of the canopy height of 1st data fork and also the urban network (width and length of sidewalk and pathways, distance from the tree to the curb, dimensions of the free growing area, spinning height and distance between trees). All data were entered in Microsoft Office Excel spreadsheet program where wealth indices were calculated: Shannon-Weaver (H '), Odum, Menhinick (Dmn) and Jentsch (QM), diversity indices; Simpson (D) McIntosh (dominance); Evenness (J) and Bulla (E) (fairness) and spatial indexes: ICA, IPO deficit, ICV, IDA IAQC, PCV IAVT, IAVPB, IAVPV, AVB, IPT IPE Sad, and Npot dfut. In the study yielded a total of 228 scheduled blocks, 145 blocks and belonging to the central zone (ZC) and 83 Central Residential (ZRC). 2321 individuals were scheduled distributed in 69 species and 27 botanical families. It was also found that the total area found 24 species of native origin and 45 exotic. Through the floristic characterization, it was observed that Licania tomentosa (Benth.) Fritsch and Azadirachta indica A. Juss s will be the most common species which represents 63.77% of the subjects. The richness indices show low diversity of species (H +, Dmn and QM), except Odum index. The dominance indexes show low diversity, showing that there is a high dominance of few species. And the equity indices show a low uniformity of the number of trees for the number of species. Overall, the ZRC proved to be less diverse, with greater dominance and less equity. As for spatial indexes s results demonstrate that the occupation of the cups with respect to area walkways are below the recommended both pa ra total area (19.81%) and for ZC (25.11%) and ZRC (16.93 %), representing a total deficit of 7570 trees, representing 76.5% percentage deployment individuals so that there was full occupancy. Regarding the number of inhabitants, the arborization of Imperatriz roads and squares is also inadequate, as demonstrated by the ICV (1.03 m² / inhabitant), IAVT and IAVPV (0.70 m² / inhabitant). Therefore, it is possible to notice that the study area in Imperatriz has low diversity, with few individuals in relation to the number of species, it also shows a disproportion between the number of trees per species. On the other hand, the study area has the potential to be planted with new trees provided there is adequate planning through a master plan for urban afforestation.

Nesse estudo investigou-se a composição faunística de insetos florestais, contrastando a diversidade de fragmentos de mata nativa com reflorestamento. Empregou-se ferramentas analíticas, incluindo as de natureza estatística e também descritiva, capazes de avaliar as diferenças na abundância e riqueza de espécies entre as áreas florestais. Especificamente, comparou-se índices faunísticos entre as diferentes áreas, analisou-se a similaridade das áreas com base na abundância e diversidade de insetos e avaliou-se a distribuição e sobreposição de guildas. A análise de diferentes grupos taxonômicos revelou resultados distintos em termos de abundância, diversidade e riqueza, com significativa dependência dos diferentes habitats. As ordens Hymenopetara e Coleoptera foram influenciadas pela característica da vegetação de cada área de coleta. Nas áreas de mata nativa foram encontrados os maiores valores de diversidade para Hymenoptera e essas áreas foram as que exibiram maior semelhança em relação à composição de espécies. Pinus tecunumannii foi a área com menor diversidade para o grupo. Para espécies da família Cerambycidae esse resultado se repetiu. Para espécies da família Elateridae Eucalyptus urograndis foi a área mais diversa. / In this study, we investigated the entomofauna of forests, confronting native fragments diversity with reforestation. We applied analytical tools, including statistical and descriptive analysis, which are able to assess differences in species abundance and richness among forest areas. Specifically, we compared faunistic indices in different areas, analysed their similarity based on insect abundance and diversity and assessed guild distribution. Different taxonomic groups showed distinct results in terms of abundance, diversity and richness, with significant dependence on habitat. The orders Hymenoptera and Coleoptera were influenced by the vegetation. In native forest we found the highest diversity for Hymenoptera and this area exhibited higher similarity with respect to the species composition. Pinus tecunumannii was the area with the lowest diversity. This result was also observed for Cerambycidade and, for Elateridae Eucalypts urograndis was the area exhibiting the highest diversity.

Submitted by Erika Demachki (erikademachki@gmail.com) on 2018-03-29T18:21:02Z No. of bitstreams: 2 Dissertação - Caroline Costa Corrêa - 2014.pdf: 2902824 bytes, checksum: b3fda66271e9778bcb3127d8281d2db4 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Erika Demachki (erikademachki@gmail.com) on 2018-03-29T19:23:49Z (GMT) No. of bitstreams: 2 Dissertação - Caroline Costa Corrêa - 2014.pdf: 2902824 bytes, checksum: b3fda66271e9778bcb3127d8281d2db4 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-03-29T19:23:49Z (GMT). No. of bitstreams: 2 Dissertação - Caroline Costa Corrêa - 2014.pdf: 2902824 bytes, checksum: b3fda66271e9778bcb3127d8281d2db4 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2014-06-16 / Outro / Anthropic systems seems to be less interesting for biodiversity conservation when compared to natural environments. Especially in tropical anthropic systems, there is a lack of knowledge about the drivers of species richness. Thus, we tested hypotheses of pond area, isolation and habitat quality that predict odonates (and separated suborders) species richness in farmland water bodies. We hypothesized that suborders will respond differently given of their distinct skills on landscape perception. We expected that landscape features would cause a smaller influence for the Anisoptera than the Zygoptera given their higher dispersion ability and less-demanding habitat requirements. We studied species richness of Odonata and suborders (Anisoptera and Zygoptera) at 53 ponds in an agricultural landscape in the Brazilian Cerrado. We used linear regressions and we selected the best models accordingly AICc and Akaike weights. As expected, there were different relations between odonates suborders and landscape features. Among all predictors, habitat quality was the main species richness driver. Despite our expectations, habitat quality was more related with Anisoptera than Zygoptera, which in turn was best related with pond area. Isolation was related in both suborders. Our results support the view that the differences between Odonata’s suborders reflect in how they perceive the landscape and that mechanisms such habitat selection can have great influence in species distributions and community dynamics. / Sistemas antrópicos não detém tanto interesse para conservação da biodiversidade quanto ambientes naturais. Especialmente em ambientes antrópicos tropicais, há uma falta de conhecimento dos mecanismos que regem a riqueza de espécies. Nesse sentido, nós testamos hipóteses de área, isolamento e qualidade de hábitat que predizem a riqueza de espécies de libélulas (Odonata e suas subordens) em corpos d’água provenientes de atividade agropecuária. Nós hipotetizamos que as subordens se relacionariam diferentemente com os preditores por possuírem distintas habilidades de perceber a paisagem. Nós esperávamos que a subordem Anisoptera fosse menos influenciada pelos preditores, pela maior capacidade de dispersão e menor exigência quanto ao hábitat. Estudamos a riqueza de Odonata (libélulas) e suas subordens (Anisoptera e Zygoptera) em 53 lagoas numa paisagem agropastoril no Cerrado Brasileiro. Nós utilizamos regressões lineares e selecionamos os melhores modelos segundo o AICc e o peso de Akaike. Como esperado, as subordens apresentam distintas relações com os preditores. Entre todos os preditores, a qualidade do hábitat foi mais importante para a riqueza de espécies estando presente nos melhores modelos. Contrariando nossas expectativas, a qualidade do hábitat esteve mais relacionada a Anisoptera do que com Zygoptera, que por sua vez teve melhores relações com a área da lagoa. O isolamento foi incluído nos modelos para ambas as subordens. Nossas resultados indicam que as subordens de Odonata tem percepções distintas da paisagem e que mecanismos como seleção de hábitat podem ter grande influência na distribuição dessas espécies e na dinâmica das comunidades.

Submitted by Rosivalda Pereira (mrs.pereira@ufma.br) on 2017-12-06T19:58:17Z No. of bitstreams: 1 EtielleAndrade.pdf: 5645245 bytes, checksum: 50dac4ede343d307c2d8d6fef223061f (MD5) / Made available in DSpace on 2017-12-06T19:58:17Z (GMT). No. of bitstreams: 1 EtielleAndrade.pdf: 5645245 bytes, checksum: 50dac4ede343d307c2d8d6fef223061f (MD5) Previous issue date: 2017-06-13 / FAPEMA / This study aimed to evaluate the diversity patterns and structure of anuran’s communities in the Cerrado remnants of the Parque Estadual do Mirado-PEM, correlating environmental variables with distribution patterns of the species and identifying factors that determine the conservation status of the park. Although the PEM is located an area of great ecological importance, few studies were conducted on the biological communities, especially of amphibians. Thus, we perform a survey about the amphibian’s species describing the richness and composition of anuran fauna and analyzing the influence of different vegetation types in their formation. The sampling was carried out through active search and survey on breeding sites in different water bodies in the PEM, which resulted in the registration of 31 species belonging to five families: Leptodactylidae, Hylidae, Bufonidae, Microhylidae and Phyllomedusidae. Species richness in the PEM was greater than that recorded by several other authors in different regions of Brazil, being formed by typical Cerrado species and by species strongly associated with other biomes. The replacement of the species among the different water bodies was considered high in all combination pairs tested, even among the nearest water bodies. The results revealed a different use in vocalization sites, forming different groups with varying degrees of overlap, with environmental heterogeneity being the best criterion to explain the high diversity and spatial and temporal distribution of the species. Structurally complex environments have greater availability of resources and the composition of communities is regulated by the degree of overlap in the use of available microenvironments. The PEM is an important corridor bioregional conservation and understand the factors that act on the ecological and biogeographic processes of species are useful in the implementation of the management plan of the park and essential for the conservation of amphibians of the Maranhão state. / O presente trabalho teve por objetivo avaliar os padrões de diversidade e estruturação das comunidades de anfíbios anuros em remanescentes de Cerrado do Parque Estadual do MiradorPEM, correlacionando as variáveis ambientais com os padrões de distribuição das espécies e identificando fatores que determinem o estado de conservação do parque. Apesar do PEM se encontrar numa área de grande importância ecológica, poucos foram os trabalhos realizados sobre as comunidades biológicas, especialmente a de anfíbios. Assim, foi realizado um levantamento das espécies de anfíbios, de modo a descrever a riqueza e a composição da anurofauna, analisando a influência dos diferentes tipos vegetacionais na sua formação. As amostras foram realizadas através de procura ativa e o levantamento em sítios reprodutivos em diferentes corpos d’água no parque que resultou no registro de 31 espécies, pertencentes à cinco famílias: Leptodactylidae, Hylidae, Bufonidae, Microhylidae e Phyllomedusidae. A riqueza de espécies no PEM foi maior que a registrada por vários outros autores em diferentes regiões do Brasil, sendo formada por espécies típicas de Cerrado e por espécies fortemente associadas a outros biomas. A substituição das espécies entre os diferentes corpos d’água amostrados foi considerada elevada em todos os pares de combinação testados, mesmo entre os corpos d’água mais próximos. Os resultados revelaram o uso diferenciado nos sítios de vocalização, formando diferentes grupos com graus variados de sobreposição, sendo a heterogeneidade ambiental o melhor critério para explica a elevada diversidade e a distribuição espaço-temporal das espécies. Ambientes estruturalmente complexos apresentam maior disponibilidade de recursos e a composição das comunidades é regulada pelo grau de sobreposição no uso dos microambientes disponíveis. O PEM é um importante corredor biorregional de conservação e entender os fatores que agem sobre os processos ecológicos e biogeográficos das espécies são úteis na implantação do plano de manejo do parque e fundamental para a conservação das espécies de anfíbios anuros do Maranhão.

The human population is rapidly urbanizing, creating dramatic changes in local land use and land cover, unprecedented species loss, and a society increasingly disconnected from nature. Nature, specifically biodiversity, has been shown to provide benefits and enhance well-being to humans. Living in an environment with reduced opportunity to interact with or experience biodiversity has increasingly been recognized as both a public health and environmental issue, whereby separation from nature can negatively impact human well-being and how humans value nature, diminishing interest in and understanding of nature and its conservation. Because urban living reduces contact with nature, it is imperative to understand how urban residents perceive and benefit from urban nature to better manage urban biodiversity to both support human well-being and conservation efforts. This study examines how urbanites perceive and benefit from two types of urban nature, trees and birds, by combining surveys of local residents with tree and bird data collected in two Midwestern agricultural cities, Cedar Rapids and Iowa City, Iowa from neighborhoods of varying urban intensity. A residential survey was distributed to these neighborhoods during the summer of 2018 to assess resident perceptions of neighborhood biodiversity and its benefits. In general, residents were not able to assess relative levels of biodiversity compared to other neighborhoods, except in the case of high tree species richness. There was a strong relationship between perceived biodiversity and actual biodiversity, as well as reported knowledge of a given taxon, but only residential perceptions of biodiversity, not actual biodiversity, were strongly related to reported benefits. Respondent perceptions of the influence of trees on their well-being exhibited strong relationships with a person’s connection to trees. Reported influence of birds on well-being was strongly related to a person’s connection to trees, connection to birds, and landscaping practices to support wild species in their yards. Actual bird species richness was significantly negatively related to perceived influence of birds on well-being. Perceived nuisances associated with trees were significantly negatively related to perceived tree species richness, while a person’s connection to trees was strongly positively related to tree nuisances. These results indicate that reported perceptions of the benefits from biodiversity are most heavily influenced by resident perceptions of biodiversity itself and orientation toward nature. This finding also implies that residents benefit from the presence of biodiversity, but that perceived benefits are only related to respondent perceptions of biodiversity, not to actual biodiversity. Further research is necessary to understand why and how this paradox occurs, yet this study provides reason to support efforts to increase knowledge of species as well as provide biodiverse environments that create opportunities for interaction with urban nature. Providing both would strengthen urban resident well-being and support biodiversity and conservation initiatives within cities.

The biological diversity of reef-fish in the Florida Keys National Marine Sanctuary (FKNMS) from 1999 – 2016 was evaluated in terms of abundance, biomass, species richness, evenness, Shannon diversity, Simpson diversity, and functional diversity, using observations collected by multiple agencies and institutions under the Reef Visual Census (RVC) program. To compare the different diversity indices species richness, Shannon diversity, Simpson diversity, and functional diversity were converted into effective number of species. I examined the seven indices by no-take marine zones, in seven benthic habitat strata, and across the three-distinct geographic subregions in the Florida Keys domain (Upper, Middle, and Lower Keys). The objective was to describe changes in reef fish community responses through time and space in the Florida Keys, and to determine whether patterns in reef fish diversity indices were attributable to levels of protection, benthic habitat strata, or geographic subregion. The goal was to develop a framework for reef fish biodiversity assessments that can inform management and policy in the FKNMS, and support updates to the periodic Condition Reports generated by the Sanctuary. Diversity indices (with the exception of evenness) were significantly higher in no-take marine zones compared to areas open to fishing. All indices were significantly different by strata type. High Relief Reef habitats had the highest abundance, biomass, richness, Simpson diversity, Shannon diversity, and functional diversity, but had moderate evenness values. The biodiversity metrics for the Upper Keys and Lower Keys were not significantly different, but both of these areas were significantly different from the Middle Keys for all indices except species richness, which did not vary by subregion. Generalized additive models revealed that the principal driver across indices was habitat structure (strata and depth). Time (year), space (latitude, longitude), and no-take marine zones (0, unprotected and 1, protected) explained roughly similar proportions of deviance across all indices. Simpson diversity, Shannon diversity, and functional diversity showed similar trends in no-take marine zones, strata, and subregion through time. The Florida Keys is characterized as having relatively low functional diversity due to a few common traits shared by many individuals and many rare traits shared by a few individuals. This suggests that the Florida Keys reef fish are less vulnerable to functional loss due to high functional redundancy among species. However, functionally rare traits, those possessed by few individuals, are vulnerable to functional loss and will have a larger impact on ecosystem functioning than species that share similar traits. Low functional diversity also suggests lower adaptability to environmental perturbations. Given the minimal robustness of traits, the ecosystem is less likely to possess functions that can withstand disturbances. The impacts of two types of perturbations were examined in a qualitative manner: hurricanes and cold-temperature events. Disturbance by hurricanes in 2004 and 2005 and the extreme cold event of January 2010 had a high impact on reef fish community composition. Between 2004 and 2006, following two consecutive years of hurricanes, abundance of reef fish declined 31%, biomass declined 53%, species richness declined 18%, Simpson diversity declined 12%, Shannon diversity declined 14%, and functional diversity declined 8%. Following a year without hurricanes in 2007 abundance of reef fish increased 11%, biomass increased 13%, richness increased 14%, Simpson and Shannon diversity increased 10%, and functional diversity increased 6%. After the January 2010 extreme cold event, reef fish abundance and biomass also declined 17%, richness declined 10%, Simpson diversity and Shannon diversity declined 5% and 6%, and functional diversity declined 2%. All matrices increased the following year, where abundance increased 13%, biomass increased 31%, richness increased 13%, Simpson diversity increased 7%, Shannon diversity increased 10%, and functional diversity increased 8%. Based on my findings and literature review, to better preserve biodiversity and enhance ecosystem functioning, I recommend prioritizing conservation efforts in source habitats (e.g., High Relief Reefs) and habitats with varying complexity by implementing corridor reserves that facilitate the natural migration of organisms between different habitat types. I also recommend prioritizing preservation of species that possess functionally rare traits with few individuals (e.g., cleaner species) by preserving areas with greater functional diversity (e.g., Higher Relief Reefs and Forereef Deep Linear Reefs).

<p>Biological diversity is controlled by an array of factors and processes all active at different spatial and temporal scales. Regional factors control what species are available to occur locally, whereas the local factors determine what species are actually capable of colonizing the locality.</p><p>I have investigated how these local and regional factors affect species richness and diversity, mainly of fish in Swedish lakes and in order to assess the impact of dispersal mode one study on bacteria was also performed. In addition, potential first steps towards speciation were investigated in perch (<i>Perca fluviatilis</i>) from two different habitats. </p><p>Fish species richness and diversity were found to be regulated by history, dispersal limitation and the local environment. In addition, striking similarities were found in the control of community composition for fish and bacteria. Both were regulated by nearly equal parts regional and local factors. The study of morphological and genetical variation in perch (<i>Perca fluviatilis</i>) revealed genetic differentiation at small spatial scales, suggesting that genetic differences can evolve between groups at strikingly small spatial scales, which might have implications for speciation in a long time perspective. </p><p>Based on these findings I conclude that space and time matter. Space has the potential to isolate sites. And both dispersal and local extinctions, it seems, might take a long time, as effects of the last ice-age can still be seen on the contemporary fish community richness and composition.</p>

Fire prone Mediterranean-type vegetation systems like those in the Mediterranean Basin and South-Western Australia are global hot spots for plant species diversity. To ensure management programs act to maintain these highly diverse plant communities, it is necessary to get a profound understanding of the crucial mechanisms of coexistence. In the current literature several mechanisms are discussed. The objective of my thesis is to systematically explore the importance of potential mechanisms for maintaining multi-species, fire prone vegetation by modelling. The model I developed is spatially-explicit, stochastic, rule- and individual-based. It is parameterised on data of population dynamics collected over 18 years in the Mediterranean-type shrublands of Eneabba, Western Australia. From 156 woody species of the area seven plant traits have been identified to be relevant for this study: regeneration mode, annual maximum seed production, seed size, maximum crown diameter, drought tolerance, dispersal mode and seed bank type. Trait sets are used for the definition of plant functional types (PFTs). The PFT dynamics are simulated annual by iterating life history processes. In the first part of my thesis I investigate the importance of trade-offs for the maintenance of high diversity in multi-species systems with 288 virtual PFTs. Simulation results show that the trade-off concept can be helpful to identify non-viable combinations of plant traits. However, the Shannon Diversity Index of modelled communities can be high despite of the presence of ‘supertypes’. I conclude, that trade-offs between two traits are less important to explain multi-species coexistence and high diversity than it is predicted by more conceptual models. Several studies show, that seed immigration from the regional seed pool is essential for maintaining local species diversity. However, systematical studies on the seed rain composition to multi-species communities are missing. The results of the simulation experiments, as presented in part two of this thesis, show clearly, that without seed immigration the local species community found in Eneabba drifts towards a state with few coexisting PFTs. With increasing immigration rates the number of simulated coexisting PFTs and Shannon diversity quickly approaches values as also observed in the field. Including the regional seed input in the model is suited to explain more aggregated measures of the local plant community structure such as species richness and diversity. Hence, the seed rain composition should be implemented in future studies. In the third part of my thesis I test the sensitivity of Eneabba PFTs to four different climate change scenarios, considering their impact on both local and regional processes. The results show that climate change clearly has the potential to alter the number of dispersed seeds for most of the Eneabba PFTs and therefore the source of the ‘immigrants’ at the community level. A classification tree analysis shows that, in general, the response to climate change was PFT-specific. In the Eneabba sand plains sensitivity of a PFT to climate change depends on its specific trait combination and on the scenario of environmental change i.e. development of the amount of rainfall and the fire frequency. This result emphasizes that PFT-specific responses and regional process seed immigration should not be ignored in studies dealing with the impact of climate change on future species distribution. The results of the three chapters are finally analysed in a general discussion. The model is discussed and improvements and suggestions are made for future research. My work leads to the following conclusions: i) It is necessary to support modelling with empirical work to explain coexistence in species-rich plant communities. ii) The chosen modelling approach allows considering the complexity of coexistence and improves the understanding of coexistence mechanisms. iii) Field research based assumptions in terms of environmental conditions and plant life histories can relativise the importance of more hypothetic coexistence theories in species-rich systems. In consequence, trade-offs can play a lower role than predicted by conceptual models. iv) Seed immigration is a key process for local coexistence. Its alteration because of climate change should be considered for prognosis of coexistence. Field studies should be carried out to get data on seed rain composition. / Feuer geprägte, mediterrane Vegetationstypen, wie sie im Mittelmeerraum und Süd-West Australien zu finden sind, gelten als globale „hotspots“ für Pflanzendiversität. Um sicher zu stellen, dass Managementprogramme zum Erhalt dieser hoch diversen Pflanzengesellschaften zielgerichtet beitragen, ist ein profundes Verständnis der wesentlichen Koexistenzmechanismen notwendig. In der aktuellen Literatur werden verschiedene Mechanismen diskutiert. Das Ziel meiner Doktorarbeit ist es, die Bedeutung der Mechanismen für den Erhalt der artenreichen, feuergeprägten Vegetation anhand eines Modells systematisch zu untersuchen. Das von mir dafür entwickelte Modell ist räumlich-explizit, stochastisch und regel- und individuenbasiert. Es ist unter Zuhilfenahme von Daten zu Populationsdynamiken parametrisiert, die über 18 Jahre im Mediterranen Buschland von Eneabba Westaustraliens gesammelt wurden. Anhand von 156 Arten sind sieben für meine Studie relevante Pflanzeneigenschaften identifiziert wurden: Regenerationsart, jährlich maximale Samenproduktion, Samengröße, maximaler Durchmesser, Trockentoleranz, Ausbreitungsart und Samenbanktyp. Kombinationen der Eigenschaften bilden funktionelle Pflanzentypen (PFTs), deren jährliche Dynamik über Lebenszyklusprozesse im Modell simuliert wird. Der erste Teil meiner Arbeit präsentiert die Studie zur Bedeutung von „trade-offs“ für den Erhalt der hohen Diversität in artenreichen Systemen. Die Simulationsergebnisse mit 288 virtuellen PFTs zeigen, dass das „trade-offs“-Konzept für die Identifizierung nicht-lebensfähiger Kombinationen von Pflanzeneigenschaften hilfreich sein kann. Allerdings kann der Shannon-Diversitäts-Index der modellierten Pflanzengesellschaft trotz der Anwesenheit von „Supertypen“ hoch sein. Ich schlussfolgere, dass „trade-off“ zwischen zwei Eigenschaften weniger wichtig für die Erklärung der Koexistenz von vielen Arten und hoher Diversität sind, als es durch konzeptionelle Modelle vorhergesagt wird. Viele Studien zeigen, dass Sameneintrag aus dem regionalen Samenpool essenziell für den Erhalt lokaler Artendiversität ist. Es gibt allerdings noch keine systematischen Studien zur Zusammensetzung des Samenregens artenreichen Systemen. Die Ergebnisse der Simulationsexperimente im zweiten Teil meiner Arbeit machen deutlich, dass ohne Sameneintrag die lokale Pflanzengesellschaft Eneabbas sich in eine Richtung entwickelt, in der nur wenige PFTs koexistieren. Mit steigender Samenimmigrationsrate erreicht die Anzahl an koexistierenden PFTs und die Shannon-Diversität schnell die Werte, die auch im Feld gefunden werden. Der regionale Sameneintrag kann also als Erklärung zur Struktur lokaler Pflanzengesellschaften dienen. Seine Zusammensetzung sollte jedoch in zukünftigen Studien berücksichtigt werden. Im dritten Teil meiner Doktorarbeit präsentiere ich Analysen zur Sensibilität der PFTs von Eneabba vorhergesagte Klimaszenarien und der Auswirkungen auf die Samenimmigration. Die Ergebnisse zeigen deutlich, dass Klimaänderungen das Potential haben, die Anzahl an ausgebreiteten Samen der meisten Eneabba PFTs zu verändern. Die Entscheidungsbaum-Analyse veranschaulicht, dass die Reaktion auf Klimaänderung PFT-spezifisch ist. In den Eneabba hängt die Sensitivität der PFTs gegenüber klimatischen Veränderungen von den PFT-spezifischen Eigenschaftskombinationen und vom Klimaszenarium ab, d.h. von der Entwicklung der Regenfallmenge und der Feuerfrequenz. Dieses Ergebnis betont, dass PFT-spezifische Reaktionen und die klimabedingten Änderungen in der Samenimmigration in Studien zum Einfluss von Klimaänderungen auf die zukünftige Artenverteilung berücksichtigt werden sollten. Die Ergebnisse aus den drei Kapiteln werden in der allgemeinen Diskussion zusammengeführt und analysiert. Das Modell wird diskutiert und Verbesserungen und Vorschläge für weitere Forschung aufgezeigt. Meine Arbeit führt zu folgenden Schlussfolgerungen: i) Es ist notwendig, empirische Arbeit und Modellierung zu kombinieren, um Koexistenz in artenreichen Systemen zu erklären. ii) Durch den gewählten Modellansatz kann die Komplexität von Koexistenz erfasst und das Verständnis vertieft werden. iii) Auf Felddaten basierende Annahmen bezüglich Umweltbedingungen und Lebenzyklus können zur Relativierung der Bedeutsamkeit von Mechanismen führen. So können Trade-offs eine geringere Rolle spielen, als konzeptionelle Modelle nahe legen. iv) Samenimmigration ist ein Schlüsselprozess für lokale Koexistenz. Deren Änderung aufgrund von Klimawandel sollte für Prognosen zu Artenvorkommen berücksichtigt werden. Feldstudien sollten durchgeführt werden, um die Datenlücken zur Samenregenzusammensetzung zu füllen.

The effect of moderate rates of nitrogen deposition on ground floor vegetation is poorly predicted by uncontrolled surveys or fertilization experiments using high rates of nitrogen (N) addition. We compared the temporal trends of ground floor vegetation in permanent plots with moderate (7–13 kg ha−1 year−1) and lower bulk N deposition (4–6 kg ha−1 year−1) in southern Sweden during 1982–1998. We examined whether trends differed between growth forms (vascular plants and bryophytes) and vegetation types (three types of coniferous forest, deciduous forest, and bog). Trends of site-standardized cover and richness varied among growth forms, vegetation types, and deposition regions. Cover in spruce forests decreased at the same rate with both moderate and low deposition. In pine forests cover decreased faster with moderate deposition and in bogs cover decreased faster with low deposition. Cover of bryophytes in spruce forests increased at the same rate with both moderate and low deposition. In pine forests cover decreased faster with moderate deposition and in bogs and deciduous forests there was a strong non-linear increase with moderate deposition. The trend of number of vascular plants was constant with moderate and decreased with low deposition. We found no trend in the number of bryophyte species. We propose that the decrease of cover and number with low deposition was related to normal ecosystem development (increased shading), suggesting that N deposition maintained or increased the competitiveness of some species in the moderate-deposition region. Deposition had no consistent negative effect on vegetation suggesting that it is less important than normal successional processes.

This thesis aims to improve our understanding of how riverine ecosystems respond to dam removal. Riverine and particularly riparian ecosystems are among the most variable and important features of all landscapes. They connect landscape elements both longitudinally and laterally, and are governed by processes such as flooding, erosion and deposition that create dynamic, diverse and heterogeneous habitats. In fact, riparian zones are among the world’s most species-rich habitats. Worldwide there are millions of dams that fragment stream and river systems, regulate flows and degrade ecosystems. Dams impact freshwater, marine and terrestrial ecosystems and threaten biodiversity by disrupting organism movements and energy flows in the landscape. An important upstream effect of dams is inundation of habitats and development of new shorelines around impounded areas. Effects downstream of dams are mainly caused by changed hydrological regimes and retention of organic and inorganic materials in reservoirs, leading to reduced transport and dispersal of for example seeds to reaches downstream. The removal of dams create expectations that biota will eventually recover. We have studied a number of dam removal projects in Sweden. Our experimental results showed that following dam removal, newly exposed soils in former impoundments were rapidly colonized by pre-removal species. Their species richness increased slightly with time and their species composition indicated a slow change towards that in the reference site. In addition, the vegetation in formerly impounded areas showed a direction of change from lentic riparian plants (high proportion of aquatics) towards lotic ones, consisting of native perennials typical of free-flowing streams. We also found that the apprehensions that former impoundments would turn into pools of mud did not come true; in fact, a process towards more pristine channel morphology was observed. After removal there was erosion and downstream transport of sediment. We found only minor effects on macroinvertebrate communities. For example, a few species decreased over the years, suggesting that dam removal in itself might cause a temporary disturbance. This highlights the importance of long-term studies after dam removal, and also the importance of comparisons with pre-removal conditions and stretches unaffected by dams. Thorough documentation of executed dam removal projects and distribution of the results and experiences are tremendously important in the planning process of future decommissioning projects. Also, our experiences have taught us that in order to attain a successful dam removal it is important to involve stakeholders such as non-governmental organizations and local inhabitants in the process.