Made available in DSpace on 2016-06-02T19:30:13Z (GMT). No. of bitstreams: 1 6775.pdf: 3213380 bytes, checksum: 36de81e56297427d70c405207779962f (MD5) Previous issue date: 2015-02-27 / Universidade Federal de Sao Carlos / The harvesting of non-timber forest products (NTFPs) has been considered as a low-impact activity. However, the increasing demand of these products made greater the exploitation, which may cause depletion of resources in Nature. Euterpe edulis Mart. (Arecaceae) is one of the most studied plant species in Brazil, because it is economically important, listed among the most relevant products provided by Atlantic Rainforest. Moreover, this species is considered ecologically important, because it is a valuable food resource for fauna. In natural conditions, E. edulis is the most abundant species in Atlantic Rainforest. Nevertheless, illegal and massive harvesting lead the species to local extinction in some remnants, which resulted in the inclusion of the palm tree amongst the endangered plant species in Brazil. In this context, this study aimed to evaluate the impact of palm tree harvest on diversity at seed rain, regeneration layer and their relationship with the adult plant community. Thus, this study was carried out in two areas at Ilha do Cardoso State Park, both of them with the same land use history, despite the occurrence of massive palm heart harvest within one of them until 20 years ago. At these areas, we sampled seed rain with and without pulp, the regeneration layer and the adult plant community. The major motivations for this study were to apply diversity analysis on the assessment of harvesting impact, and to provide scientific information to the establishment of viable guidelines to the sustainable harvest of palm tree products. Our results showed that the abundance of E. edulis is related to the change of diversity patterns and species composition in seed rain and regeneration layer, and may have an influence on species composition in the future. This confirms the general hypothesis of this study, i.e. the disturbance caused by palm heart harvesting causes changes on species abundance enough to modify plant community structure. These changes could be detected even it has been 20 years after the end of illegal harvesting within the harvested area. The results also indicate that it is viable to make the sustainable harvest of E. edulis products, considering a selective removal of adult individuals and avoiding total suppression of clumps of palm tree. These actions promote heterogeneity on species composition of seed rain and regeneration layer. / Pelas caracteristicas de seu uso e exploracao, a extracao de produtos florestais nao madeireiros (PFNMs) e tida como sendo de baixo impacto ecologico. Entretanto, a crescente utilizacao destas materias primas nos mercados consumidores levou a um aumento da demanda de exploracao, o que pode levar a deplecao dos produtos explorados. Euterpe edulis (Arecaceae) e uma das especies vegetais mais estudadas do pais, pois tem uma alta importancia economica, sendo um dos principais PFNMs obtidos da Mata Atlantica. Alem disso, a especie tem grande importancia ecologica, por ser um recurso alimentar valioso para a fauna. Em condicoes naturais, E. edulis e a especie dominante na comunidade adulta nas areas cobertas por Floresta Atlantica. Entretanto, a exploracao ilegal e massiva levou a especie a extincao local em certos remanescentes de Mata Atlantica, culminando em sua inclusao entre as especies ameacadas no pais. Diante deste contexto, o presente estudo teve como objetivo geral avaliar o impacto da exploracao do palmito de E. edulis sobre a diversidade na chuva de sementes, no estrato regenerante e a sua relacao com a comunidade adulta. Deste modo, o estudo foi realizado em duas areas no Parque Estadual Ilha do Cardoso, ambas com historico de uso similar, porem, uma delas sofreu exploracao massiva de palmito de E. edulis ate ha cerca de 20 anos, enquanto que a outra nao foi alvo deste tipo de uso. Nestas areas, amostramos a chuva de sementes com e sem polpa, o estrato regenerante e a comunidade adulta. As principais motivacoes deste estudo foram aplicar analises de diversidade na avaliacao e fornecer subsidio cientifico para o estabelecimento de diretrizes mais especificas e viaveis para o uso sustentavel deste produto, que e economicamente importante, mas que tambem e considerada uma especie chave na Floresta Atlantica. Os resultados mostraram que a abundancia de E. edulis altera padroes de diversidade e composicao em especies na chuva de sementes e no estrato regenerante, podendo influenciar na composicao das comunidades vegetais no futuro, confirmando a hipotese geral desta tese, de que o disturbio causado pela exploracao de E. edulis produz alteracoes na densidade de individuos da palmeira suficiente para modificar a estrutura das comunidades vegetais. Tais mudancas puderam ser detectadas mesmo apos 20 anos sem a atividade de exploradores ilegais na area estudada. Os resultados indicam, tambem, que o uso sustentavel do palmito de E. edulis pode ser viavel, considerando a remocao seletiva de individuos adultos, evitando a total supressao de adensamentos desta palmeira, promovendo a heterogeneidade da composicao da chuva de sementes e do estrato regenerante.

Ecótonos campo-floresta no sul do Brasil são originados pela expansão de ecossistemas florestais sobre os campestres, um processo natural gerado por mudanças climáticas de larga escala espacial e temporal. Este processo provoca mudanças vegetacionais que consequentemente modificam os padrões de distribuição, composição e riqueza faunística. Assim, ecótonos campo-floresta são sistemas adequados para inferir sobre a influência de processos históricos, biogeográficos e ecológicos na estruturação de comunidades. Para respondermos questões relacionadas a processos agindo em diferentes escalas espaciais, distribuímos as amostragens de modo a obtermos um panorama espacial da estrutura das assembléias. Assim, a proposta de estudo desenvolvido no Capítulo I foi avaliar o papel do ambiente e de dinâmicas espaciais sobre a composição, riqueza de espécies e número de indivíduos em metacomunidades de pequenos mamíferos não-voadores de ecótonos campo-floresta. Os resultados demonstram que os componentes ambiental, espacial e a estrutura espacial do ambiente contribuem igualmente na explicação da variância na composição de espécies, enquanto o ambiente foi mais importante em explicar mudanças na riqueza de espécies e número de indivíduos. Assim, concluímos que requerimentos de nicho das espécies e processos regionais como a limitação da dispersão, o distanciamento de centros de especiação e distribuição geográfica e o processo de expansão florestal conjuntamente explicam variações na estrutura de metacomunidades de pequenos mamíferos não-voadores em ecótonos campo-floresta no Sul do Brasil. No Capítulo II, inferimos sobre os processos gerando os padrões de coexistência de pequenos mamíferos não-voadores em assembléias baseando-se em afinidades filogenéticas e funcionais. Considerando estas similaridades, avaliamos se a diferenciação de nicho ou os filtros ambientais compõem processos importantes para explicar os padrões de coexistência em escalas de hábitat, paisagem e região. Os resultados apontam um padrão de agrupamento filogenético e funcional em todas as escalas avaliadas, embora um padrão de repulsão foi registrado no interior florestal, atestando a influência da diferenciação de nicho estruturando as assembléias de pequenos mamíferos não-voadores nesta porção do gradiente campo-floresta. A predominância do padrão de agrupamento filogenético e funcional afirma a ação de filtros ambientais como processos majoritariamente importantes em explicar os padrões de coexistência de espécies e indivíduos de pequenos mamíferos não-voadores nas escalas avaliadas. Desta forma, o estudo compõem uma das primeiras tentativas para definir os processos de estruturação de assembléias de pequenos mamíferos não-voadores neotropicais combinando aspectos taxonômicos, funcionais e filogenéticos, levantando também questões de conservação da biodiversidade nos sistemas ecológicos estudados. / Grassland-forest ecotones in southern Brazil are originated by forest expansion on grasslands, a natural process generated by climate shifts in large spatial and temporal scales, which causes vegetation changes and likely affects distribution, composition and faunal richness patterns. Thus, grassland-forest ecotones in southern Brazil are suitable systems to infer about influence of historical, biogeographical and ecological processes structuring communities. In order to make these inferences, we spatially sampled non-flying small mammals to characterize the spatial structure of species assemblages. The study proposal of Chapter I was to evaluate the role of environment and spatial dynamics on the composition, species richness and individuals number of nonflying small mammals metacommunities in grassland-forest ecotones. The results shows that environment, space and spatial structure of environment explained equally variations in species composition, while environment variables was the most important component explaining changes in species richness and number of individual. Thus, we conclude that niche requirements and regional processes like dispersal limitation, increase in distance of speciation cores and geographic distribution centers and the forest expansion process explain together variation in metacommunities structure of non-flying small mammals in grassland-forest ecotones at southern Brazil. In Chapter II, we inferred the coexistence patterns of non-flying small mammals based on phylogenetic and functional affinities. Considering these ecological similarities, we evaluate whether niche differentiation or environmental filters processes are responsible for patterns of species coexistence in habitat, landscape and regional scales. Results indicated a phylogenetic and functional cluster across all evaluated scales, although phylogenetic and functional repulsion was registered at forest interior, proving the importance of niche differentiation structuring non-flying small mammals assemblages in this grassland-forest gradient portion. Prevalence of phylogenetic and functional cluster across all scales attests environmental filters as important processes explaining species and individual coexistence patterns in habitat, landscape and regional scales. Therefore, this study comprises one of first attempts to define processes underlying the structure of neotropical non-flying small mammals assemblages combining taxonomic, functional and phylogenetic aspects, concurrently addressing important questions to biodiversity conservation in the ecological systems under study.

Submitted by (lucia.rodrigues@ufrpe.br) on 2016-08-24T13:55:27Z No. of bitstreams: 1 Felipe Rodrigo de Carvalho Rabelo.pdf: 1193812 bytes, checksum: b440d9ffc17e08e8e148bb16817c5fe3 (MD5) / Made available in DSpace on 2016-08-24T13:55:28Z (GMT). No. of bitstreams: 1 Felipe Rodrigo de Carvalho Rabelo.pdf: 1193812 bytes, checksum: b440d9ffc17e08e8e148bb16817c5fe3 (MD5) Previous issue date: 2012-03-30 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Data are presented for 2004, 2007 and 2010 on physiognomy, dynamics, diversity, species composition and density of the wood plant canopy (CA with CBH> 15 cm) and understory (UN, with a circumference at ground level between > 3cm and CAP <15cm) in a gradient edge-interior formed at 35 years in an Atlantic Forest fragment, Igarassu, PE. In 2004, three environments were evaluated: edge (0-50m), intermediate (50-100m) and interior (more than 150m from the tree line), and analyzed by environment of 1000 m², divided into plots of 10 × 10m, to measure the CA individuals. In each plot was plotted a subplot of 5 × 5m for the UN sample. In 2010 branches were collected from three adult individuals of the species for the collection of sample disks. The number of individuals (NI), basal area (BA) and demographic rates in the three environments the CA showed no edge effect or if there was, since the edge is sealed. In UN the edge had lower values of NI and BA demographic rates and higher than the inside. Differences between strata occur, regardless of sealing the border, as the young plants that are still in UN are more sensitive than the trees of the CA, the changes caused by the creation of the border. Rates of loss and gain of BA and BA rotation in NI and UN showed higher values than in the CA, which points to a stratum with major changes. In CA there were no differences in species richness between environments, distinct from that observed in UN. The composition in CA environments closer to the tree line were very similar and distinct from the interior, indicating that there has been no recovery in all environments while the composition of the UN had low similarity. The edges of CA and UN showed higher concentration of individuals at intervals of class values lower density wood. It can be concluded that the CA has regained biomass, although the edge and have not recovered to intermediate composition. The UN also suffer from edge effect. If we consider that the environment had more edge classes of individuals in wood density of less value and that there is an inverse relationship between wood density and mortality rates / annual periodic increment in diameter can be assumed that the different composition of the edge would be result of the increased mortality of species of lower density wood. / São apresentados dados de 2004, 2007 e 2010 sobre fisionomia, dinâmica, diversidade, composição de espécies e densidade da madeira de plantas do dossel (DO, com CAP > 15cm), e sub-bosque (SB, com circunferência ao nível do solo entre > 3cm e CAP < 15cm) em um gradiente borda-interior formado a 35 anos em um fragmento de Mata Atlântica, Igarassu, PE. Em 2004, foram avaliados três ambientes: borda (0-50m), intermediário (50-100m) e interior (mais de 150m do limite florestal), sendo analisados 1000 m² por ambiente, divididos em parcelas de 10×10m, para medir os indivíduos do DO. Em cada parcela foi plotada uma sub-parcela de 5×5m para amostragem do SB. Em 2010 foram recolhidos ramos de três indivíduos adultos das espécies, para coleta de discos amostrais. O número de indivíduos (NI), área basal (AB) e taxas demográficas no DO dos três ambientes mostraram que não houve efeito de borda ou se houve, a borda já estaria selada. No SB a borda teve menores valores de NI e AB e maiores taxas demográficas que o interior. Diferenças entre os estratos acontecem, independente do selamento da borda, já plantas jovens do DO que ainda estão no SB são mais sensíveis que as árvores do DO, as mudanças causadas pela criação da borda. Taxas de perda e ganho de AB e de rotatividade em NI e AB no SB apresentaram valores maiores que no DO, o que aponta para um estrato com maiores mudanças. No DO não ocorreram diferenças de riqueza de espécies entre os ambientes, distinto do observado no SB. A composição no DO nos ambientes mais próximos ao limite florestal foram bastante similares e distintos do interior, indicando que ainda não houve recuperação da composição enquanto todos os ambientes do SB tiveram baixa similaridade. As bordas do DO e SB apresentaram maior concentração de indivíduos em intervalos de classe de menores valores de densidade de madeira. Pode-se concluir que o DO já recuperou a biomassa, embora os ambientes de borda e intermediário não tenham recuperado a composição de espécies. O SB ainda sofrer efeito de borda. Se considerarmos que o ambiente de borda teve mais indivíduos em classes de densidade da madeira de menor valor e que há uma relação inversa entre densidade da madeira e taxas de mortalidade/incremento periódico anual em diâmetro pode-se supor que a composição diferenciada da borda seria resultado da maior mortalidade de espécies de menor densidade da madeira.

Submitted by Marlene Santos (marlene.bc.ufg@gmail.com) on 2016-08-10T17:58:39Z No. of bitstreams: 1 Tese - Fernanda Alves Martins - 2016.pdf: 7514352 bytes, checksum: 26ab210eab88a067ec233c173df6ef87 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2016-08-15T13:35:27Z (GMT) No. of bitstreams: 1 Tese - Fernanda Alves Martins - 2016.pdf: 7514352 bytes, checksum: 26ab210eab88a067ec233c173df6ef87 (MD5) / Made available in DSpace on 2016-08-15T13:35:27Z (GMT). No. of bitstreams: 1 Tese - Fernanda Alves Martins - 2016.pdf: 7514352 bytes, checksum: 26ab210eab88a067ec233c173df6ef87 (MD5) Previous issue date: 2016-05-24 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The interactions between the organisms and their physical environment and among the organisms themselves occur at definite spatial scales, and give rise to spatial patterns that may be assessed to a better understanding of these relationships. Thus, in order to understand the variation in species diversity, it is necessary to link the scale in which the variation is measured to the scale in which the processes operate. The main objective of this work is thus to identify the factors that best explain the diversity of dragonflies’ tropical assemblages and determine how they interact across scales. The work is based on the Community Assembly conceptual framework that relies on the idea that community assembly is affected by spatial processes hierarchically arranged. Dragonflies are good models because they comprise two distinct groups of species regarding to body size, thermoregulatory responses and dispersal ability. Due to their ecological differences, they may respond differently to local as well as to regional environmental conditions. Despite of their ecological differences, our results suggest that richness patterns for both groups are affected by the same factors, i.e., they respond in a similar fashion to the analysed factors. In regional scales, environmental filters, such as temperature seasonality, affect species richness. The abundance is the main predictor of local species richness. Nevertheless, the assemblages’ compositional patterns are different. Comparatively, Zygoptera (low-dispersal group) assemblages are more affected by local scale processes than Anisoptera. Our results suggest a better integration of metacommunity theory (focused on the role of dispersal shaping different spatial dynamics in the assemblages) and community assembly theory. The fact that the dispersal processes is more important at smaller scales indicate the potential importance of occupancy dynamics at this scale, calling for explicitly incorporating dispersal, affecting the spatial dynamics at different spatial scales. Furthermore, our results suggest that rather than being mutually exclusive, neutral and deterministic processes acts jointly on community assembly. / As interações ecológicas entre os organismos e seus ambientes ocorrem em diferentes escalas espaciais, dando origem a padrões espaciais de composição e riqueza das espécies. O objetivo principal desta tese é investigar fatores que operam em diferentes escalas na estruturação das comunidades de libélulas tropicais. O estudo se apoia no marco conceitual de Community Assembly, que se baseia na ideia de que a organização das comunidades ecológicas é afetada por processos hierárquicos espacialmente organizados. Libélulas são bons modelos de estudo porque compreendem dois grupos de espécies que diferem em características ecofisiológica tais como tamanho corporal afetando as relações com seus ambientes locais e regionais, influenciando os padrões de diversidade resultantes. A subordem Zygoptera compreende organismos com menor tamanho corporal e possuem menor habilidade de dispersão enquanto que Anisoptera é composta por espécies com maior tamanho corporal e maior habilidade de dispersão. Apesar das diferenças ecofisiológicas, nossos resultados indicam que a riqueza de espécies nos dois grupos de libélulas responde de maneira similar aos fatores analisados. Em escalas regionais, a riqueza de espécies de ambos os grupos é influenciada de maneira consistente por filtros ambientais, tais como as variações sazonais da temperatura ambiente. Em escalas locais, a riqueza dos dois grupos é determinada primariamente pela abundância total. No entanto, os padrões de composição das comunidades são diferentes para Zygoptera e Anisoptera. As comunidades de Zygoptera são mais afetadas por fatores que ocorrem em escala local do que Anisoptera. Nossos resultados sugerem que a dispersão desempenha um importante papel em escalas espaciais reduzidas, indicando a importância que as dinâmicas de ocupação podem ter na formação das comunidades ecológicas. Nesse sentido, sugerimos uma maior integração da teoria de metacomunidades (que enfatiza a importância do processo de dispersão na formação das dinâmicas espaciais nas comunidades) e com a teoria de Community Asssembly, com a incorporação explícita do processo de dispersão, afetando as dinâmicas espaciais nas diferentes escalas. Além disso, nossos resultados sugerem que processos neutros e processos determinados pelo nicho não são mutuamente exclusivos, mas atuam conjuntamente na formação das comunidades ecológicas.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Ants belong to a hyperdiverse social insect group with many species used as ecological indicators of their habitat conditions. This study aims to analyze richness, species composition, diversity, evenness, and environmental variables associated to leaf-litter ant fauna of eight forest fragments in the municipality of Santa Maria, Central Depression region of Rio Grande do Sul State, Brazil. The sampling followed standard protocol through a 200-m transect placement by fragment. In order to proceed statistical analyses, the fragments were grouped in two categories, according to their conservation status, preserved or on regeneration. Eighty ant species belonging to 24 genera and nine subfamilies were registered. Myrmicinae, Formicinae and Ponerinae, and Camponotus, Hypoponera and Pheidole were respectively the richest subfamilies and genera and Solenopsis sp. 1 and Gnamptogenys striatula were the most frequent species. Shannon-Wiener and Margalef diversity indexes had the same ordination among fragments, highest at FRJB 01, and lower at FRCE 05. The dominance indexes had the same ordination among higher values but differed among lower ones. FRJB 01 for Simpson and FPMC 06 for Berger-Parker. The fragments separation on two distinct groups was showed by NMDS and confirmed by similarity analyses. The dissimilarity percentage analysis showed that Gnamptogenys striatula and Wasmannia sp. 3 had the highest contribution for conservation status differentiation. The preserved fragments had more similarity among each other than the regeneration ones, highlighting Gnamptogenys striatula and Solenopsis sp. 1 at the first group, and Solenopsis sp. 1 and Hypoponera sp. 4 at the other. Only edge effect showed relationship with species richness among all environmental variables measured. Based on results, the studied ant fauna communities showed noticeably richness and composition partially related to their habitat traits. Although, other factors as adjacent vegetational areas isolation, regeneration time and history and intensity of disturbances could be interfering on these communities structure and their associated biodiversity. / Formigas pertencem a um grupo de insetos sociais hiper-diversos que possuem espécies usadas como indicadores ecológicos das condições dos habitats em que ocorrem. O presente estudo visa analisar riqueza, composição de espécies, diversidade, similaridade e variáveis ambientais associadas à mirmecofauna de serapilheira de oito fragmentos florestais no município de Santa Maria, localizado na região da Depressão Central do Rio Grande do Sul, Brasil. As amostragens seguiram um protocolo padronizado, através do estabelecimento de um transecto de 200 m em cada fragmento. Para fins de análise estatística, os fragmentos foram agrupados em duas categorias, de acordo com seu estado de conservação, preservados ou em regeneração. Foi registrado um total de 80 espécies de formigas, pertencentes a 24 gêneros e nove subfamílias. Myrmicinae, Formicinae e Ponerinae foram as subfamílias mais ricas e Camponotus, Hypoponera e Pheidole, os gêneros com o maior número de espécies. As espécies mais freqüentes foram Solenopsis sp. 1 e Gnamptogenys striatula. Os índices de diversidade de Shannon-Wiener e Margalef tiveram a mesma ordenação entre os fragmentos, sendo maiores em FRJB 01, e menores para FRCE 05. Os índices de dominância apresentaram a mesma ordenação em relação aos valores maiores, mas diferiram em relação aos mínimos, com FRJB 01 menor para Simpson e FPMC 06 para Berger-Parker. O NMDS evidenciou a separação dos fragmentos nos dois grupos distintos, confirmado pela análise de similaridade. A análise de porcentagem de dissimilaridade mostrou que Gnamptogenys striatula e Wasmannia sp. 3 tiveram maior contribuição para a diferenciação dos estados de conservação. Os fragmentos preservados apresentaram maior similaridade entre si do que os em regeneração, destacando-se Gnamptogenys striatula e Solenopsis sp. 1 nos primeiros, e Solenopsis sp. 1 e Hypoponera sp. 4 nos outros. De todas variáveis ambientais mensuradas, apenas tamanho da borda apresentou relação com a riqueza de espécies. Baseado nos resultados encontrados, as comunidades de mirmecofauna estudadas apresentaram riqueza e composição expressivas parcialmente relacionadas com as condições de seus habitats. No entanto, outros fatores como isolamento de áreas de vegetação contíguas, tempo de regeneração e histórico e intensidade das perturbações sofridas podem estar interferindo na estruturação dessas comunidades e sua biodiversidade associada.

The purpose of this study was to collect baseline data of juvenile scleractinian coral density, spatial variability, size variability, and species composition across the linear shore parallel hard bottom coral communities offshore Broward County, Florida. Adult coral population data was also collected and compared with that of the juvenile coral population to better understand the local coral demographics and potential factors that influence the population structure. The juvenile and adult coral data from the Broward County coral communities was then compared to a second study region 50 kilometers south to identify latitudinal changes in the coral population structure. The results of this study found that the densities and the list of coral species observed within the Broward County study region did fall within the range of densities found in other studies completed along the southern portion of the Florida Reef Tract and the Caribbean. Despite having similar species richness to other Caribbean studies, there was an overwhelming dominance of only a few species. This was also found in the adult coral population in the Broward study region. The densities of both the juvenile and adult coral populations were significantly positively correlated as well as their number of species observed across the sites in the Broward County study region. Additionally, the highly dominant species found in the juvenile population were in the adult population. Despite increasing coral density and diversity with decreasing latitude found in other studies conducted along the Florida Reef Tract, the results from this study were not as clear. Density of corals and the number of coral species did increase from north to south on the Outer reef however there was a significant decrease in the depth of the sample sites. On the Pavement habitat the density of juvenile corals increased from north to south however the number of coral species did not increase. The density and number of species of adult corals did not increase on the Pavement habitat with decreasing latitude as well making the results unclear.

The historic Everglades Ridge and Slough landscape maintained regularly spaced and elevated sawgrass ridges interspersed among exposed deeper-water sloughs; however, widespread but irregular hydrologic modification has degraded much of this landscape patterning. My study assessed the effects of hydrologic modification on vegetation community distinctness within the Ridge and Slough landscape through sampling species composition at fine-scales along a hydrologic gradient to measure the magnitude of segregation of species among patch types. The results show that vegetation community and topographic variation degradation is widespread, with distinctness differences proceeding and possibly being driven by topographic variation loss. Vegetation responses to past hydrologic regime modifications are likely affected by temporal lags; however, vegetation distinctness regeneration may also be hindered by a vegetatively homogeneous alternative stable state. Hydrologic regime restoration is critical for Ridge and Slough patterned landscape reestablishment, but management targets are complicated by vegetation response lags and possibly alternative stable states.

Oak habitats are rich in saproxylic species, but the habitat is declining with loss of diversity due to encroachment which decrease the vitality of oaks. The present explorative study compared results from a study conducted in 1994, with present species communities to observe if there has been change in species composition and what factors that can explain species diversity and composition. The results revealed that the overall species composition between 1994 and 2018 has changed. There were 130 species recorded in 2018 compared to 108 species in 1994 (31 new species were recorded in 2018, and 9 species lost from the study in 1994). There was a high species turnover recorded per individual tree, and the species composition between the living and encountered dead trees did not differ. Species composition was affected by canopy cover, and trunk circumference (CCA P-value 0.001 and 0.014 respectively). Unlike 1994, there were no variables in 2018 that could explain the association with species numbers. Warmer conditions recorded during the sampling period have probably led to increased flight activity of beetles and therefore increasing chances of capturing more species and individuals. The warmer conditions possibly shadowed the effects of the explanatory variables in explaining the changes in species numbers. Perhaps the change in species composition could also be attributed to existing management interventions that may be supporting an increasing species number of saproxylic beetles, however no strong conclusions could be drawn. Management interventions such as the recruitment of new oaks should be encouraged and intensified in order to provide habitats and support stable populations as the loss of oaks may lead to increased risk of extinction of the saproxylic beetles in the study area.

Horseshoe crabs (Limulus polyphemus) have been harvested along the east coast of the United States since the 1800s, however a Fishery Management Plan (FMP) was only recently created for this species. To date, there have not been any studies that have attempted to identify or quantify bycatch in the horseshoe crab trawl fishery. A horseshoe crab trawl survey was started in 2001 to collect data on the relative abundance, distribution, and population demographics of horseshoe crabs along the Atlantic coast of the United States. In the present study, species composition data were collected at sites sampled by the horseshoe crab trawl survey in 2005 and 2006. Seventy-six different taxa were identified as potential bycatch in the horseshoe crab trawl fishery. Non-metric multidimensional scaling (NMS) was used to cluster sites and identify the spatial distribution of taxa. Sites strongly clustered into distinct groups, suggesting that species composition changes spatially and seasonally. Species composition shifted between northern and southern sites. Location and bottom water temperature explain most of the variation in species composition. These results provide a list of species that are susceptible to this specific trawl gear and describe their distribution during fall months throughout the study area. Identifying these species and describing their distribution is a first step to understanding the ecosystem-level effects of the horseshoe crab trawl fishery. / Master of Science

Models of climate change predict that temperature will increase during the 21th century and the largest warming will take place at high northern latitudes. In addition to warming, predictions for northern Europe include increased annual precipitation and a higher proportion of the precipitation during winter falling as rain instead of snow. These changes will substantially alter the hydrology of rivers and streams and change the conditions for riverine communities. The warming is also expected to result in species adjusting their geographic ranges to stay within their climatic tolerances. Riparian zones and wetlands are areas where excess water determines the community composition. It is therefore likely that these systems will be highly responsive to alterations in precipitation and temperature patterns. In this thesis we have tested the predicted responses of riparian vegetation to climate-driven hydrologic change with a six year long transplant experiment (I). Turfs of vegetation were moved to a new elevation with shorter or longer flood durations. The results demonstrate that riparian species will respond to hydrologic changes, and that without rare events such as unusually large floods or droughts, full adjustment to the new hydrological regime may take at least 10 years. Moreover, we quantified potential effects of a changed hydrology on riparian plant species richness (II) and individual species responses (III) under different climate scenarios along the Vindel River in northern Sweden. Despite relatively small changes in hydrology, the results imply that many species will become less frequent than today, with stochastic extinctions along some reaches. Climate change may threaten riparian vegetation along some of the last pristine or near-natural river ecosystems in Europe. More extensive loss of species than predicted for the Vindel River is expected along rivers in the southern boreal zone, where snow-melt fed hydrographs are expected to be largely replaced by rain-fed ones. With a seed sowing experiment, we tested the differences in invasibility between open wetlands, forested wetlands and riparian zones (IV). All six species introduced were able to germinate and survive in all habitats and disturbance levels, indicating that the tested wetlands are generally invisible. Germination was highest in open wetlands and riparian zones. Increasing seed sowing density increased invasion success, but the disturbance treatments had little effect. The fact that seeds germinated and survived for 2 to 3 years in all wetland habitats indicates that wetland species with sufficiently high dispersal capacity and propagule pressure would be able to germinate and establish here in their respective wetland type. Our results clearly demonstrate that a changed climate will result in substantial changes to functioning, structure and diversity of boreal wetland and riparian ecosystems. To preserve species rich habitats still unaffected by dams and other human stressors, additional protection and management actions may have to be considered.