<p>The work in this thesis deals with effects of changed species richness on process rates among stream-living macroinvertebrates. Global biodiversity is decreasing rapidly and it is poorly known what the consequences of this loss may be for ecosystems and the services they provide. Hence, it is important to investigate the potential effects of losing species. In streams, deforestation, introduction of non-native species, pollution and channelization are examples of events that may affect species richness negatively. In this thesis emphasis is on changes in species richness within functional feeding groups (FFGs) of stream-living macroinvertebrates. The FFGs used were shredding detritivores, grazers, filter feeders and predators - all of which uphold important ecological processes in streams. Along with an observational field study, species richness was manipulated in laboratory and field experiments to investigate the effects of changed species richness on process rates and thus ecosystem functioning.</p><p>The results show that effects of changed species richness on process rates may be dramatic. Among the shredding detritivores there were negative effects on leaf mass loss, regardless whether fixed, random or predicted sequences of species loss was investigated. These effects could be attributed to either species richness per se or species composition. However, among the other FFGs the relationship between species richness and process rates was less consistent. In filter feeders, there was no or a negative effect of decreasing species richness while both grazers and predators showed positive effects of species loss.</p><p>The results also show that the most important interactions between species in an experiment, thus potentially in a natural community, are likely to determine what the effect of species loss on process rates will be. Facilitation and niche differentiation lead to reduced process rates if species are lost, while mechanisms, such as interspecific resource or interference competition, produce the opposite effect. Furthermore, in systems with a diminishing resource, the first two mechanisms may become more important over time enhancing the effect of species loss in the long term.</p><p>In conclusion, effects of species loss may be dramatically negative or positive even if lost species are classified as redundant. The effect in the short term most likely depends on which species are lost, on the original species composition and on the underlying mechanisms. Questions remaining to be answered are how important the observed effects are in more complex systems and if they are persistent over time? Future studies will tell. </p>

<p>A tool for management and conservation of valuable forests in Sweden are WKH:s. In this study WKH:s different in size, connectivity, amount of dead wood and quality of logs were investigated for species richness of bryophytes and brackets on coniferous logs. The aim was to clarify which scales and features that was important for the diversity of species as well as for individual species. The results showed that the amount of dead wood was most important on the site scale, and some species were affected at the landscape scale, a positive effect of valuable tracts. On the scale of individual logs, factors such as diameter, sun exposure, succession stage, contact with ground and ground bryophytes cover was most important. Red-listed species preferred logs with large diameter and late successional stages. The conclusion was that the quality of the substrate and the amount of dead wood was most important, but the amount of WKH:s on the landscape scale was also important for some species.</p>

<p>Since the start of the industrialisation, the deposition of nitrogen and sulphur and the atmospheric concentrations of greenhouse gases have increased. The main objectives of this study were to find how these changes in climate and deposition can change the vegetation of mire ecosystems and the growth of <i>Sphagnum</i>species. Two main approaches were applied: re-investigated of two mires previously investigated 40-50 years ago and experiment manipulations. </p><p>The plant species diversity had decreased on one of the two re-investigated mires (Skattlösbergs Stormosse; central Sweden), but the total number of species was unchanged on the other (Åkhultmyren; southern Sweden). On Skattlösbergs Stormosse, an acidification was found in the high pH areas, coinciding with reduction in rich fen species. At Åkhultmyren, there was a similar reduction in pH, but the changes in the plant composition also indicated increased nutrient levels and a drier mire surface. Therwere large changes in species composition on Åkhultmyren. For instance <i>Scheuchzeria palustris</i> had disappeared from the investigated area. Further, the cover of Scots pine (<i>Pinusylvestris</i>) had increased, which can be explained by a changed ground-water table regime. Monitoring of pines growing on a bog over a ten-year period showed that pines growing higher above the ground-war table had higher survival than lower-growing pines.</p><p>Experimental addition of nitrogen during 3-4 years reduced <i>Sphagnum </i>growth in bogs and poor fens repressenting a wide range of ambient nitrogen deposition. A changed interspecific competitive relation was found between <i>S. lindberg</i>and <i>S. balticum</i> when increasing nitrogen influx, but the competitive relations between two hummock-growing species pairs did not change in a three-year nitrogen fertilization study. Sulphur additiodid not affect the production or length increment in <i>S. balticum</i>. An increased temperature reduced <i>Sphagnum </i>growth, but there were no indications of altered competitive relationshipbetween hummock and hollow inhabiting <i>Sphagnum </i>species in a four-year experiment.</p>

Since the start of the industrialisation, the deposition of nitrogen and sulphur and the atmospheric concentrations of greenhouse gases have increased. The main objectives of this study were to find how these changes in climate and deposition can change the vegetation of mire ecosystems and the growth of Sphagnumspecies. Two main approaches were applied: re-investigated of two mires previously investigated 40-50 years ago and experiment manipulations. The plant species diversity had decreased on one of the two re-investigated mires (Skattlösbergs Stormosse; central Sweden), but the total number of species was unchanged on the other (Åkhultmyren; southern Sweden). On Skattlösbergs Stormosse, an acidification was found in the high pH areas, coinciding with reduction in rich fen species. At Åkhultmyren, there was a similar reduction in pH, but the changes in the plant composition also indicated increased nutrient levels and a drier mire surface. Therwere large changes in species composition on Åkhultmyren. For instance Scheuchzeria palustris had disappeared from the investigated area. Further, the cover of Scots pine (Pinusylvestris) had increased, which can be explained by a changed ground-water table regime. Monitoring of pines growing on a bog over a ten-year period showed that pines growing higher above the ground-war table had higher survival than lower-growing pines. Experimental addition of nitrogen during 3-4 years reduced Sphagnum growth in bogs and poor fens repressenting a wide range of ambient nitrogen deposition. A changed interspecific competitive relation was found between S. lindbergand S. balticum when increasing nitrogen influx, but the competitive relations between two hummock-growing species pairs did not change in a three-year nitrogen fertilization study. Sulphur additiodid not affect the production or length increment in S. balticum. An increased temperature reduced Sphagnum growth, but there were no indications of altered competitive relationshipbetween hummock and hollow inhabiting Sphagnum species in a four-year experiment.

The work in this thesis deals with effects of changed species richness on process rates among stream-living macroinvertebrates. Global biodiversity is decreasing rapidly and it is poorly known what the consequences of this loss may be for ecosystems and the services they provide. Hence, it is important to investigate the potential effects of losing species. In streams, deforestation, introduction of non-native species, pollution and channelization are examples of events that may affect species richness negatively. In this thesis emphasis is on changes in species richness within functional feeding groups (FFGs) of stream-living macroinvertebrates. The FFGs used were shredding detritivores, grazers, filter feeders and predators - all of which uphold important ecological processes in streams. Along with an observational field study, species richness was manipulated in laboratory and field experiments to investigate the effects of changed species richness on process rates and thus ecosystem functioning. The results show that effects of changed species richness on process rates may be dramatic. Among the shredding detritivores there were negative effects on leaf mass loss, regardless whether fixed, random or predicted sequences of species loss was investigated. These effects could be attributed to either species richness per se or species composition. However, among the other FFGs the relationship between species richness and process rates was less consistent. In filter feeders, there was no or a negative effect of decreasing species richness while both grazers and predators showed positive effects of species loss. The results also show that the most important interactions between species in an experiment, thus potentially in a natural community, are likely to determine what the effect of species loss on process rates will be. Facilitation and niche differentiation lead to reduced process rates if species are lost, while mechanisms, such as interspecific resource or interference competition, produce the opposite effect. Furthermore, in systems with a diminishing resource, the first two mechanisms may become more important over time enhancing the effect of species loss in the long term. In conclusion, effects of species loss may be dramatically negative or positive even if lost species are classified as redundant. The effect in the short term most likely depends on which species are lost, on the original species composition and on the underlying mechanisms. Questions remaining to be answered are how important the observed effects are in more complex systems and if they are persistent over time? Future studies will tell.

De ekologiskt betydelsefulla småbiotoperna blir allt färre i det moderna jordbruket på grund av intensifieringen av jordbrukslandskapet som resulterat i ett allt mer fragmenterat landskap. För att kunna ge småbiotoper, såsom åkerholmar, ett optimalt skydd behövs flera studier om organismerna på holmarna, deras diversitet och spridning. I denna undersökning studeras artrikedomen av mossor och lavar på busk- och trädbekädda samt öppna åkerholmar i ett öppet- och ett skogsdominerat landskap. Analysen av artrikedom i studien tyder på att de finns fler arter av mossor och lavar i det öppna landskapet i förhållande till det skogsdominerade landskapet samt på de åkerholmarna som saknade busk- och trädvegetation. Dessa miljöer består av torr och stenig mark och växer igen relativt långsamt, vilket är gynnsamt för vissa mossor och lavar. Det fanns ingen signifikant korrelation mellan diversitet och storleken på åkerholmarna eller mellan diversitet och holmarnas avstånd till skog. Antalet arter i ett habitat kan bero på regionala artpoolen samt antalet potentiella kolonisatörer men även lokala processer. Vidare är det viktigt att nämna att studien tyder på att diversitet av mossor och lavar påverkas av förhållandena på holmarna, såsom busk- och trädtäckningen. Detta i kombination med en variation inom dessa små biotoper kan skapa goda förutsättningar för ett landskap med hög diversitet. / The ecologically important small remnant habitats are becoming fewer in modern agriculture due to the intensification of agricultural landscapes that have resulted in an increasingly fragmented landscape. In order to provide an ideal conservation framework for small habitats, such as midfield islets, several studies about the organisms on the islets, their diversity and distribution are needed. In this study I investigated the diversity of mosses and lichens on open midfield islets with and without shrubs and trees in an open and a forest-dominated landscape. The analysis of species diversity in the study suggests that, overall; there are more species of mosses and lichens in the open landscape in relation to the forest-dominated landscape, and on the opened islets lacking shrub and tree vegetation. These environments consist of dry and rocky soils and overgrow relatively slowly, which is favourable for mosses and lichens. There was no significant correlation between diversity and size of the midfield islets or their distance to forest. The number of species in a habitat may depend on regional species pool and the number of potential colonizers but also local processes. Furthermore, it is important to mention that the study suggests that the diversity of mosses and lichens is influenced by the conditions on the midfield islands, such as shrub and tree cover. These conditions, combined with a variation within these small habitats can create good conditions for a landscape with high diversity.

A tool for management and conservation of valuable forests in Sweden are WKH:s. In this study WKH:s different in size, connectivity, amount of dead wood and quality of logs were investigated for species richness of bryophytes and brackets on coniferous logs. The aim was to clarify which scales and features that was important for the diversity of species as well as for individual species. The results showed that the amount of dead wood was most important on the site scale, and some species were affected at the landscape scale, a positive effect of valuable tracts. On the scale of individual logs, factors such as diameter, sun exposure, succession stage, contact with ground and ground bryophytes cover was most important. Red-listed species preferred logs with large diameter and late successional stages. The conclusion was that the quality of the substrate and the amount of dead wood was most important, but the amount of WKH:s on the landscape scale was also important for some species.

Made available in DSpace on 2015-03-26T13:30:40Z (GMT). No. of bitstreams: 1 texto completo.pdf: 1259817 bytes, checksum: 312ebed75b287bd629b3efca4b0ea9ea (MD5) Previous issue date: 2012-02-24 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / No capítulo 1, este estudo investiga os determinantes da diversidade e abundância de grilos de serapilheira, e as possíveis interações com feições geomorfológicas. Ainda, nós propomos uma abordagem analítica que inclui amostragem local passiva como uma explicação necessária para a variação da diversidade e evidencia eventuais efeitos do ambiente nas relações diversidade-abundância. Concluímos que os processos biológicas regulando o número de espécies de grilos não são diretamente afetados por feição geomorfológica. A riqueza local é mais provavelmente limitada por processos amostrais do pool regional. No capítulo 2, avaliamos se a diversidade de gêneros de grilos sul-americanos pode ser empiricamente explicada por área de distribuição e tamanho corporal. Analisamos as espécies reportadas pela Orthoptera Species File para a região Neotropical e estimamos a área de distribuição e biomas interceptados para cada gênero. A diversidade aumenta com a área, mas o aumento é maior em áreas descontínuas. A diversidade aumenta com tamanho corporal e área tanto em áreas contínuas quanto em áreas descontínuas. A distribuição descontínua podem ou subestimar a distribuição verdadeira ou superestimar o escopo do gênero. O aumento da diversidade com tamanho corporal foi contrário às nossas expectativas. Isso pode ser resultado de efeito amostral, isto é, grilos maiores são mais facilmente amostrados e identificados. Concluímos que a distribuição de dados de grilos, embora incipiente, são relevantes para explicar diversidade de espécies entre gêneros. Os processos biológicos envolvidos nas relações empíricas merecem melhor investigação. / On chapter 1, this study investigates drivers of the diversity and abundance of litter crickets, and their possible interactions with the geomorphological feature. Moreover, we propose an analytical approach which includes local passive sampling as a necessary explanation for diversity variation and thus highlights eventual effective influence of environment on diversity and diversity-abundance relationship. It is concluded that the biological processes regulating number of species are not directly affected by the geomorphological feature. Local richness is most probable limited solely by a sampling process of the regional pool, and sample size is determined by factors affecting all species equally, in other words, affect the number of individuals. At Chapter 2, we aimed to evaluate if genus diversity of South-American crickets (Orthoptera: Grylloidea) may be empirically explained by distribution area and body size. We analyzed all species reported in the Orthoptera Species File with geographic distribution range reported for the Neotropics. We estimated reported distribution area, as well as intercepted biome area for each genus. Diversity increased with area, but this increase was higher and steeper in discontinuous than continuous areas. Diversity increased with body and area in both continuous and discontinuous distribution areas. Discontinuous distribution records may either underestimate actual distribution area, or overestimate the genus scope. The increase of diversity with body size was opposite to our expectations. This could result from sampling effect, where larger cricket species with smaller body size would be under-represented due to taxonomic issues. We conclude that cricket distribution data, although sparse and not-systematic, are relevant to explain species diversity among genera. The biological processes involved in the empirical relationships deserve further investigation.

Made available in DSpace on 2015-04-17T14:55:31Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 2030208 bytes, checksum: a9ca9fd74d6c51300138eb942585c8c8 (MD5) Previous issue date: 2013-04-23 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Ecological analysis of the structure of understory bird communities of forest remnants of Atlantic Forest of Paraíba. South America is the region with the highest bird diversity in the world. The Atlantic Forest biome in Brazil is the second most diverse. Its portion in Paraíba integrates Pernambuco Endemism Centre, a region that is home of two-thirds of the bird species present in the biome. The present study investigated the bird communities in the understory of three Atlantic Forest remnants of Paraíba through the method of capture with mist nets. Ten nets were positioned in the forest understory in eight different points in each remnant, in a summit of 48 day samples, in a total effort of 2.895 hours-net. A total of 333 specimens of 44 species were captured, divided into 19 families. The recapture rate was 2%. The species with the highest representation were Arremon taciturnus (n = 40), Chiroxiphia pareola (n = 32) and Conopophaga melanops (n = 28), the latter being an endemic species considered as threatened in the Atlantic Forest with the status of vulnerable . Endangered species totaled 16% of the records and the same value was found for the endemic. Species richness among the three remnants did not differ (χ² = 0.667, d.f = 2, p = 0.7165), and according to the communities of birds found, diversity was considered low, with a predominance of dominant and generalists species. The species composition was little similar among the remnants, suggesting that the size, matrix and the availability of different microhabitats in each remnant may have influenced the species presence. The Reserva Particular do Patrimônio Natural Engenho Gargaú remnant was the one with the highest number of endemic and threatened species, as well as with the most understory insectivores, thus suggesting that this remnant is best conserved. / Análise ecológica da estrutura das comunidades de aves de sub-bosque de remanescentes florestais de Mata Atlântica da Paraíba. A América do Sul é a região que possui a maior diversidade de aves no mundo. No Brasil a Mata Atlântica é o segundo bioma mais diverso. A Mata Atlântica da Paraíba integra o Centro de Endemismo Pernambuco, uma região que abriga cerca de 2/3 de das espécies de aves presentes no bioma. O presente estudo investigou as comunidades de aves de sub-bosque de três remanescentes de Mata Atlântica da Paraíba através do método de captura com redes de neblina. Dez redes foram posicionadas no sub-bosque florestal em oito pontos distintos ao longo de cada remanescente, tendo sido realizadas 48 dias de amostragem ao todo, totalizando 2.895 horas-rede. Ao todo foram capturados 333 indivíduos de 44 espécies divididas em 19 famílias. A taxa de recaptura foi de 2%. As espécies com maior representatividade foram Arremon taciturnus (n = 40), Chiroxiphia pareola (n = 32) e Conopophaga melanops (n = 28), sendo esta última espécie endêmica e ameaçada da Mata Atlântica com status de vulnerável . As espécies ameaçadas totalizaram 16% dos registros e o mesmo valor foi encontrado para as espécies endêmicas. A riqueza de espécies entre os três remanescentes não diferiu (χ² =0,667; g.l = 2; p = 0,7165), e de acordo com as comunidades de aves encontradas, a diversidade foi considerada baixa, com predominância de espécies dominantes e generalistas. A composição das espécies foi pouco similar entre os remanescentes, sugerindo que o tamanho, a matriz e a disponibilidade de microhabitats distintos de cada um possam ter influenciado na presença das espécies. O remanescente Reserva Particular do Patrimônio Natural Engenho Gargaú foi o que apresentou o maior número de espécies endêmicas e ameaçadas, assim como insetívoros de sub-bosque, sugerindo assim que tal remanescente seja mais bem conservado.

Made available in DSpace on 2015-04-17T14:55:33Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 12252069 bytes, checksum: 1600b25f25cfdf6ca826316a966d8ec7 (MD5) Previous issue date: 2014-01-24 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The objective of the present study was to estimate the population density of jaguar (Panthera onca) and ocelot (Leopardus pardalis), and the abundance and species richness of other terrestrial mammals on the Fazenda São Nicolau, in the north of the Brazilian state of Mato Grosso, located in the southern Amazon basin. Camera traps were used to record the presence of the different species. Twelve collecting points were established in forested areas and sampled during four years between 2008 and 2011, with a total of 3603 trap-days of records. In impacted areas, 16 points were sampled in a rotating system over two years (2009 and 2010), with a total of 658 traps-days of records. Population parameters were estimated for the felids only in the forested areas, while the mammal community was analyzed in both habitats. Population density was estimated considering both open and closed populations, with individuals being identified based on pelage coloration patterns. The conventional capture-recapture method (CAPTURE) and the Spatially Explicit (SECR) model were used for the closed population analysis, while the Jolly-Seber and Pollock's robust design were used for the open population. A total of 10 jaguar were identified from 88 photo-records. Jaguar sexual ratio was estimate in 1,5:1. Population estimates of the jaguar were performed only for 2010 using closed population models. Population density based on the CAPTURE and the maximum distance traveled (MMDM) average was estimated at 4.12 ind/km ². The SECR estimated density was 3.03 (±1,57) ind/km ². Overall, 24 ocelots were identified from 134 photo-records, with density being estimated for all four years based on both open and closed population models. Ocelot sexual ratio was 1:1. Population density was estimated in the four seasons following the use of closed and open population analysis. The results of the SECR were more moderate, estimating 7.87 (± 3.0), 14.17 (± 6.5), 10.46 (± 4.4) and 7.36 (± 2.9) ind/km² between 2008 and 2011, respectively. The Jolly-Seber model obtained the highest estimates, 19.54, 25.01, 16.03 and 19.74 ind. / km ², each season. Survival and population growth were also estimated for this species. This result indicates that the spatially explicit model was adequate for the understanding of the population dynamics of the two felid species, although the robust design returned a greater number of demographic parameters, complementing the population analysis. The average population density of the ocelot for four seasons in southern Amazonia based on SECR, was estimated on 11.81 (± 2.29) ind/100km2 in a region with at least 25% of the disturbed area. Total mammalian richness for the study area was estimated at 26 species, with between 21 and 24 species being recorded in any given year. In the altered habitat, species richness was estimated to be 18 species, although only 17 were recorded (13 in one year and 15 in the other). The most common species were Tayassu pecari in the forested area and Cerdocyon thous in the altered habitat. The analysis of 24 indices of Beta diversity indicated a more homogeneous distribution of species in the forested areas in comparison with the altered habitat. Overall, this study has demonstrated that camera-trapping studies of population density or community structure require monitoring over two or more years for the collection of data for reliable analyses. This reinforces the importance of long-term studies for the understanding of the dynamics of wild populations and community structure. / Este estudo teve o objetivo de estimar as populações de onça-pintada (Panthera onca) e de jaguatirica (Leopardus pardalis) e a riqueza e a abundância dos mamíferos terrestres na Fazenda São Nicolau, no norte do estado de Mato Grosso, sul da Amazônia. Utilizei armadilhas-fotográficas para registrar as espécies. Amostrei 12 pontos em áreas de floresta durante quatro temporadas (2008 a 2011), totalizando 3603 dias/câmeras. Nas áreas alteradas amostrei 16 pontos em duas temporadas (2009 e 2010), em sistema de rodízio, totalizando 658 dias/câmeras. Estimei parâmetros populacionais dos felídeos apenas nas áreas de floresta. Analisei a comunidade de mamíferos nos dois ambientes. A densidade populacional das duas espécies de felídeos foi estimada analisando a população fechada e aberta dentro de ocasiões de captura de 10 dias, aproximadamente. Identifiquei os indivíduos comparando as diferenças nas malhas da pelagem. Utilizei o método convencional de captura e recaptura (CAPTURE) e o modelo espacialmente explícito (SECR) para as análises de população fechada. Para análises de população aberta, utilizei o modelo Jolly-Seber e o desenho robusto de Pollock. Identifiquei 10 onças, em 88 eventos fotográficos nas quatro temporadas. A razão sexual (M:F) foi de 1,5:1. As estimativas populacionais da onça-pintada foram realizadas somente para 2010 utilizando os modelos de população fechada. A densidade populacional com base no CAPTURE e na média da máxima distância percorrida (MMDM) foi estimada em 4,12 ind./km². O SECR estimou a densidade em 3,03 (±1,57) ind./km². No caso das jaguatiricas, identifiquei 24 indivíduos em 134 eventos fotográficos. A razão sexual foi de 1:1. Estimei a densidade populacional nas quatro temporadas utilizando os modelos de população fechada e aberta. Os resultados do SECR foram mais moderados, estimando 7,87 (±3,0), 14,17 (±6,5), 10,46 (±4,4) e 7,36 (±2,9) ind./km², entre 2008 e 2011, respectivamente. Entretanto o modelo Jolly-Seber foi o que obteve as maiores estimativas, sendo 19,54, 25,01, 16,03 e 19,74 ind./km², a cada temporada. Também estimei a sobrevivência e o crescimento populacional desta espécie. O modelo SECR estabilizou as estimativas de densidade mesmo com os valores de buffer mais elevados, evitando superestimar a população. Estes resultados indicam que o modelo espacialmente explícito foi adequado para a compreensão da dinâmica populacional das duas espécies de felídeos. Entretanto, o desenho robusto retornou um maior número de parâmetros demográficos, complementando as análises populacionais. A densidade populacional média da jaguatirica para as quatro temporadas ao sul da Floresta Amazônica com base no SECR, foi estimada em 11,81 (±2,29) ind/100km2, em uma região com pelo menos 25% de área alterada. O número de espécies observadas de mamíferos entre as temporadas variou de 21 a 24 na área de floresta, e a riqueza foi estimada em 26 espécies. Na área alterada o número de espécies observadas nas duas temporadas foi de 13 e 15 e a riqueza foi estimada em 18 espécies, sendo que o total de espécies observadas foi 17. As espécies mais representativas foram o Tayassu pecari, na área de floresta e o Cerdocyon thous, na área alterada. A análise gráfica composta de 24 índices de diversidade beta indicou que a área de floresta teve maior homogeneidade na ocorrência das espécies do que na área alterada. Este estudo demonstra que quando há uma coleta de dados por mais que uma temporada, seja para investigar a população de uma espécie ou a estrutura de uma comunidade, os resultados não serão os mesmos, mesmo utilizando os mesmos procedimentos. Isso reforça a importância dos estudos da dinâmica das populações silvestres para compreender a oscilação na abundância e também na riqueza da comunidade.