Thesis (MScConEcol)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: Restoration practices commonly make use of a reference condition in order to restore a site to a better ecological state than it is currently in. The selection process and relevance of the reference condition has not yet been tested in upland Western Cape rivers especially with relation to spatial and temporal scales. This thesis sought to evaluate whether space (longitudinal) and time (temporal) influence riparian plant community composition (laterally), how it influences the community composition and whether these differences impacts the selection of a reference condition used in restoration practices. In order to investigate the role longitudinal position, sites were selected across three longitudinal zones: mountain stream, transitional and upper foothills. Historic sites used in a previous study on riparian vegetation of upland rivers were resampled and datasets used for temporal comparisons between undisturbed sites, sites recovering after clearing of invasive alien plants and sites affected by fire. Riparian vegetation communities showed differences between longitudinal zones, basins and rivers. The species responsible for marginal zone identity (plants in close proximity to the active channel), determined using relative cover abundance varied, with Isolepis prolifera responsible for the group identity in the mountain stream and transitional sites but in the foothills Calopsis paniculata, Drosera capensis and Metrosideros angustifolia saplings were responsible for lateral zone identity. The lower dynamic (transitional between wet and drybank) had no similarities between different longitudinal zones across rivers. In the lower zone Pteridium aqualinum was mostly responsible for the identity. The upper bank had no single species responsible for group identity. The species described to be typical for the reference condition on these particular rivers by other studies were mostly present in the comparable lateral zone but it was however not always responsible for the identity of the specific lateral zone. By comparing selected environmental variables such as horizontal distance from active channel, elevation and substrate calibre with different longitudinal zones’ riparian vegetation species distribution, different combinations were produced. The mountain streams showed the strongest relationship with horizontal distance and elevation in combination to one another and the upper foothills horizontal distance from the active channel was linked most strongly to vegetation positioning. These results confirm the importance of space when attempting to assess, study or restore riparian communities. Temporally, sites had stronger similarity to data collected during the same sampling period than with historic data. Also, the overall relative species abundance did not show significant change to be present at a site scale. The changes in community composition were found to be due to a lateral zone scale variation in species abundance. As expected the undisturbed rivers showed less variation in species responsible for temporal changes than the recovering and fire-exposed rivers. Species responsible for changes in relative abundance at a lateral zone scale were Metrosideros angustifolia, Morella serrata, Brabejum stellatifolium, Isolepis prolifera, Elegia capensis, Prionium serratum and Calopsis paniculata. Due to the species diversity not changing much temporally but the relative abundance of specific species showing much variation over time it can be concluded that the changes are not diversity based but instead driven by changes in relative abundances of species typical for a lateral zone. The spatial and temporal variation in riparian vegetation community composition was found to be significant enough to suggest that the use of a fixed reference condition for all Western Cape rivers would not be feasible due to clear differences between basins. Secondly when selecting a reference site the spatial location of this site should be within the same longitudinal zone since bank shape does influence riparian plant species distribution. Finally the temporal comparison between sites showed high diversity in species abundances but small differences in diversity overall. This would suggest that a general community description specific to 1) where the site is situated and 2) based on the present riparian vegetation community composition within a specific basin may be more realistic and achievable for restoration and environmental management purposes as opposed to using site descriptions from the past and reference sites too far upstream or downstream from the restoration site. / AFRIKAANSE OPSOMMING: Herstel praktyke maak algemeen gebruik van 'n verwysing toestand om 'n terrein te herstel na 'n beter ekologiese toestand as wat dit tans is. Die keuringsproses en relevansie van die verwysing toestand is nog nie in die boonste gedeeltes van Wes-Kaap Riviere getoets nie, veral met betrekking tot ruimtelike en tydskale nie. Hierdie tesis het gesoek om te evalueer of ruimte (longitudinaal) en tyd (temporaal) rivieroewers plant gemeenskap samestelling (lateraal) beïnvloed en of hierdie verskille die keuse van 'n verwysing toestand in die herstel praktyke beïnvloed. Ondersoek terreine was oor drie longitudinale sones geselekteer: berg stroom, oorgangs en boonste hange terreine. Historiese terreine was weer ondersoek en die datastelle was gebruik vir die temporale vergelykings tussen onversteurde terreine, terreine wat herstel na die skoonmaak van indringer spesies en wat geraak was deur 'n brand. Oewerplantegroei gemeenskappe het verskille tussen longitudinale sones, rivier-kom en rivier takke gewys. Die spesies wat verantwoordelik was vir marginale zone (plante in nabye afstand met die aktiewe rivier kanaal) identiteit, bepaal met behulp van relatiewe dekking hoeveelheid, het gevarieer met Isolepis prolifera verantwoordelik vir die groep identiteit in die berg stroom en oorgangs trerreine, maar in die boonste hange was dit Calopsis paniculata, Drossera capensis en Metrosideros angustifolia boompies wat verantwoordelik was vir die laterale sone identiteit. Die laer dinamiese area het geen ooreenkomste tussen marginale gebiede van verskillende longitudinale sones gehad nie. In die onderste sone was Pteridium aqualinum meestal verantwoordelik vir die groepering se identiteit. Die boonste bank het nie 'n enkele spesie wat verantwoordelik was vir die groep identiteit gehad nie. Die spesies beskryf as tipies vir die laterale sone deur Reinecke et al. (2007) was meestal teenwoordig in die beskryfde laterale sone van hierdie studie, maar dit was egter nie altyd verantwoordelik vir die identiteit van die laterale sone gemeenskap nie. Verskillende lengte sones het gekorreleer met verskillende omgewingsveranderlikes wat sterkste gekoppel kon word aan die verspreiding van spesies. Die bergstrome het die sterkste verhouding met horisontale afstand en hoogte in kombinasie met mekaar gehad en in die boonste hange was horisontale afstand van die aktiewe kanaal die sterkste gekoppel aan plantegroei posisie. Die belangrikheid van ruimte is onmiskenbaar ten opsigte van evaluering, bestudering en die herstel van rivieroewers gemeenskappe. Terreine het sterker ooreenkoms met data gehad wat tydens dieselfde tydperk versamel was, as met historiese data. Die algehele relatiewe spesies hoeveelheid het egter nie beduidende verandering getoon op 'n terrein skaal nie. Soos verwag was het die onversteurde riviere minder temporale variasie in spesies getoon as die herstellende en brand blootgestelde riviere. Spesies wat verantwoordelik was vir die verandering in relatiewe hoeveelhede op 'n laterale sone skaal was M. angustifolia, Morella serrata, Brabejum stellatifolium, I. prolifera, Elegia capensis, Prionium serratum en C. paniculata. As gevolg van die diversiteit van spesies wat nie baie verander het tydelik nie, maar die relatiewe hoeveelheid van spesifieke spesies wat heelwat variasie oor tyd getoon het, kan dit afgelei word dat die veranderinge nie diversiteit gebaseerd was nie, maar eerder gedryf was deur veranderinge in relatiewe hoeveelhede van tipiese spesies in 'n laterale sone. Die ruimtelike en tydelike variasie in oewerplantegroei gemeenskap samestelling was beduidende genoeg om voor te stel dat die gebruik van 'n vaste verwysing toestand vir alle Wes-Kaapse riviere nie haalbaar sou wees nie as gevolg van duidelike verskille tussen riviere. Tweedens, by die kies van 'n verwysing terrein moet die ruimtelike plek van hierdie terrein in dieselfde lengte sone wees aangesien bank vorm 'n invloed op rivieroewer plant verspreiding het. Laaastens, het die tydelike vergelyking tussen terreine hoë diversiteit in spesies verspreidings maar klein verskille in algehele diversiteit gehad. Dit stel voor dat 'n algemene beskrywing van die gemeenskap wat spesifiek op 1) waar die terrein geleë is en 2) gebaseer op die huidige oewerplantegroei gemeenskap samestelling binne 'n spesifieke rivier netwerk dalk meer realisties en haalbaar vir hersteel en bestuurs doeleindes sou wees. Hierdie benadering word verkies bo die gebruik van n terrein beskrywings uit die verlede en verwysing terreine te ver stroomop of stroomaf van die herstel gebied.

Os riachos em trechos de cabeceira são fontes importantes de água, sedimento e biota, apresentam baixa produtividade primária autóctone e são fortemente influenciados pela vegetação ripária, pois nesses trechos, a energia básica para sustentação das comunidades é proveniente do input de matéria orgânica particulada alóctone. Portanto, o desmatamento e o uso inadequado do solo afetam negativamente as condições dos riachos, o que é considerado umas das principais causas de degradação ambiental em países em desenvolvimento. Uma avaliação rápida da qualidade do habitat físico pode prover uma idéia geral das condições dos riachos e detectar alterações antrópicas de maneira rápida, fácil e de baixo custo. A combinação desta ferramenta com a avaliação de outros fatores físicos, químicos e biológicos, especialmente, a composição das assembléias de macroinvertebrados bentônicos, é essencial para o desenvolvimento de estratégias de monitoramento nesses ecossistemas. O objetivo geral do presente estudo foi identificar as principais alterações antrópicas sobre os riachos da APA Embu Verde e selecionar aqueles que apresentaram melhores condições de habitat para a fauna bentônica, a fim de conhecer a composição dessas assembléias e sua relação com o habitat. Para atender os objetivos, primeiramente foram avaliados 23 sítios amostrais, por meio de um Protocolo de Avaliação de Habitat e algumas variáveis relevantes. A partir daí, foram selecionados 4 riachos com base, prioritariamente, na semelhança das características do entorno, pequena variação no nível de degradação ambiental e potencialidade de oferta de habitats para os macroinvertebrados. Procedeu-se, então, à avaliação da vegetação ripária, do canal dos riachos e dos tipos de substratos para melhor compreensão da relação dos macroinvertebrados com o meio físico. A principal alteração antrópica na APA Embu Verde é o desmatamento da vegetação ripária natural, sendo evidenciados indícios de efeitos negativos sobre os riachos, como erosão nas margens e deposição de sedimentos finos. As variáveis que melhor explicaram a variação da fauna estão relacionadas ao porte do riacho, energia cinética de suas águas e aos tipos de substrato. Este último foi determinante para a composição das assembléias de macroinvertebrados bentônicos, pois estas variaram mais entre os tipos de substratos do que entre os sítios amostrais. A família Chironomidae foi dominante em todos os sítios e tipos de substratos. A diversidade e riqueza de família aumentaram com a estabilidade dos substratos inorgânicos / Headwater streams are relevant suppliers of water, sediment, and biota. They support low autochthonous primary productivity and suffer strong influence from riparian vegetation as in these streams the basic energy for communities maintenance has its origin in the allochthonous particulate organic matter. Hence, deforestation and inadequate soil use negatively affect stream conditions, being among the main causes of environmental degradation in developing nations. A rapid assessment of the physical habitat quality can provide a general idea about stream conditions and detect anthropic changes in a rapid, easy and low cost manner. The combination of this tool with the assessment of other physical, chemical and biological features, especially the benthic macroinvertebrate assemblage composition, is essential to the development of monitoring strategies in those ecosystems. The general aim of this study was to identify the main anthropic changes on streams of Environmental Protection Area Embu Verde and to select those with better habitat conditions for benthic fauna. So it would be possible to know the assemblages composition and its relation with the habitat. First we evaluated 23 sampling sites using a Habitat Assessment Protocol and some relevant variables. Therewith we selected four streams, grounded primarily on the similarity of the surroundings features, little variation on the environmental degradation level and potential of habitats to macroinvertebrates. Then we made an assessment of stream riparian vegetation and substrate types to improve the understanding of the relation between macroinvertebrates and the physical environment. The major anthropic change in the sampling area is the deforestation of the natural riparian cover, and we observed evidences of its negative effects on streams, as bank erosion and fine sediment deposition. Variables that better explained fauna variations are related to the stream size, water kinetic energy and substrate types. Substrate was determinant to the composition of benthic macroinvertebrate assemblages as these ones variate more with the substrates types than with the sampling sites. Chironomidae dominated in all the sampling sites and substrate types. Family diversity and richness increased with the stability of inorganic substrates

Os ecossistemas aquáticos são afetados por processos que ocorrem em escalas finas (locais) e amplas (regionais). Os processos locais incluem, por exemplo, filtros ambientais e interações interespecíficas, enquanto que os regionais abrangem principalmente questões relacionadas à dispersão de indivíduos. O entendimento de como esses processos atuam sobre comunidades, populações e interações em peixes de riachos é fundamental para a conservação dos ecossistemas aquáticos, pois permite predizer as consequências de alterações antrópicas e fornece subsídios para ações de manejo e políticas de conservação. Na presente tese, eu desenvolvi cinco estudos em distintas escalas espaciais. Cada um é apresentado em capítulos distintos. Nos capítulos 1 e 2, eu abordei questões relacionadas à compreensão de como alterações antrópicas feitas em distintas escalas espaciais influenciam as diversidades alfa e beta de comunidades de peixes de riachos. No capítulo 3, eu procurei entender como processos previstos na teoria de metacomunidades influenciam mudanças temporais na composição e abundâncias de espécies em comunidades locais. No capítulo 4, eu estudei como os impactos antrópicos levam a alterações no papel trófico e no intestino de populações de uma espécie generalista e persistente. Por fim, no capítulo 5, eu usei uma abordagem de aninhamento, desenvolvida inicialmente na Ecologia de Comunidades, para avaliar a ocupação de larvas de uma espécie de quironomídeo (Diptera) sobre o corpo de seu hospedeiro (uma espécie de peixe da família Loricaridae). / Aquatic ecosystems are influenced by processes that occur at fine (local) and broad (regional) scales. Local processes include, for example, environmental filters and interspecific interactions, whereas regional processes encompass mainly questions regarding individual dispersion. Knowledge on how these processes affect communities, populations and interactions in stream fish is essential for conservation of aquatic ecosystems, as it allows predicting consequences of human-alterations and provides subsidy for management actions and conservation policies. In this dissertation, I developed five studies using distinct spatial scales. I presented each one in a separate chapter. In the 1st and 2nd chapters, I addressed questions concerned with the understanding of how human alterations at different spatial scales influence alpha and beta diversity of stream fish communities. In the 3rd chapter I looked for understanding how processes predicted in metacommunity theory influence mid- to long-term changes in composition and species abundances of local communities. In the 4th chapter, I studied how anthropic impact drives modification in the trophic role and intestine of a generalist and persistent fish species. Lastly, in the 5th chapter, I employed nestedness approach previously developed for Community Ecology to evaluate occupation of chironomid species larvae (Diptera) on the body of its host (an armored catfish species of the family Loricariidae).

A l’image du Rhône au sud-est de la France, les fleuves font l’objet de multiples usages, entrainant des modifications profondes de leurs dynamiques fluviales. Par conséquent, les fonctionnements hydro-sédimentaire et écologique de leurs chenaux ainsi que de leurs plaines alluviales sont altérés. Des programmes intégrés de restauration s’attellent à définir les potentiels et les risques liés à de tels ‘écosystèmes anthropo-construits’ et de comprendre les interactions entre divers facteurs de contrôle ayant influencé leur formation. La présente étude s’est focalisée sur 293 casiers Girardon – des unités rectangulaires délimitées par des digues submersibles longitudinales et latérales construites dans le lit mineur au 19ème siècle afin d’améliorer la navigabilité du Rhône. Ceux-ci sont distribués sur quatre secteurs court-circuités au 20ième siècle pour la production hydro-électrique. Nous avons analysé les patrons spatio-temporels de la sédimentation, ainsi que la structure et la composition des boisements grâce à des données issues de la télédétection et de terrain. Nous proposons également un modèle conceptuel des facteurs de contrôle et des processus potentiels en lien avec les patrons observés. Quatre-vingts pourcents des casiers ont évolué du stade aquatique à un stade terrestre et boisé, suivant des trajectoires historiques variées à la fois inter- et intra-secteurs. Les boisements diffèrent en caractéristiques structurelles de boisements de référence plus naturels. Leur composition est plus proche de celle des systèmes matures que pionniers. Nous observons également une forte présence d’espèces allochtones, comme par exemple l’Érable negundo (Acer negundo), invasive, en particulier dans les stades de régénération. Notre approche comparative constitue une première étape pour démêler les effets cumulatifs des facteurs de contrôle et hiérarchiser leurs rôles individuels. Nous avons constaté que des facteurs locaux jouent un rôle majeur, en particulier la connectivité au chenal principal court-circuité. L’évolution des facteurs environnementaux eux-mêmes a contribué à la complexité des patrons. Ce travail ouvre la voie à des futures études sur des écosystèmes anthropo-construits sur cours d’eau, et donne une nouvelle perspective aux gestionnaires du Rhône relativement à son échelle spatiale innovante. / The multiple uses made of large rivers, such as the Rhône in south-eastern France, have provoked profound modifications of their fluvial dynamics. As a consequence, the hydro-sedimentary and ecological functioning of their channels and floodplains are highly altered. Integrated restoration programmes struggle in defining potentials and risks related to such ‘novel ecosystems’ and to understand the various interacting drivers which influence their formation. This study comparatively focused on 293 dike fields—rectangular units delimited by longitudinal and lateral submersible dikes constructed in the channel in the late 19th century to promote the navigability of the Rhône. They are distributed over four reaches by-passed in the 20th century for hydro-electric energy production. We investigated the spatio-temporal patterns of sediment deposition and the structure and composition of the forest stands using remote sensing and field data. We also propose a conceptual model of potential drivers and processes behind the observed patterns. Eighty percent of the dike fields have evolved from the aquatic to a terrestrial and forested stage, following variable historical trajectories both between and within reaches. The forest stands presented structural characteristics which differed from more natural reference stands and compositional characteristics closer to mature than to pioneer systems. They featured a high presence of non-native species, such as the invasive Box elder (Acer negundo). Our comparative approach constituted a first step to disentangle the cumulative effects of the drivers and define their individual roles: we discovered a prominent role of local factors, especially the connectivity to the main by-passed channel. The evolution of the environmental factors themselves added to the complexity of the patterns. This work provides a basis for future studies of novel ecosystems on rivers, and a new perspective to river managers on the Rhône due to its innovative spatial-scale.

Os riachos em trechos de cabeceira são fontes importantes de água, sedimento e biota, apresentam baixa produtividade primária autóctone e são fortemente influenciados pela vegetação ripária, pois nesses trechos, a energia básica para sustentação das comunidades é proveniente do input de matéria orgânica particulada alóctone. Portanto, o desmatamento e o uso inadequado do solo afetam negativamente as condições dos riachos, o que é considerado umas das principais causas de degradação ambiental em países em desenvolvimento. Uma avaliação rápida da qualidade do habitat físico pode prover uma idéia geral das condições dos riachos e detectar alterações antrópicas de maneira rápida, fácil e de baixo custo. A combinação desta ferramenta com a avaliação de outros fatores físicos, químicos e biológicos, especialmente, a composição das assembléias de macroinvertebrados bentônicos, é essencial para o desenvolvimento de estratégias de monitoramento nesses ecossistemas. O objetivo geral do presente estudo foi identificar as principais alterações antrópicas sobre os riachos da APA Embu Verde e selecionar aqueles que apresentaram melhores condições de habitat para a fauna bentônica, a fim de conhecer a composição dessas assembléias e sua relação com o habitat. Para atender os objetivos, primeiramente foram avaliados 23 sítios amostrais, por meio de um Protocolo de Avaliação de Habitat e algumas variáveis relevantes. A partir daí, foram selecionados 4 riachos com base, prioritariamente, na semelhança das características do entorno, pequena variação no nível de degradação ambiental e potencialidade de oferta de habitats para os macroinvertebrados. Procedeu-se, então, à avaliação da vegetação ripária, do canal dos riachos e dos tipos de substratos para melhor compreensão da relação dos macroinvertebrados com o meio físico. A principal alteração antrópica na APA Embu Verde é o desmatamento da vegetação ripária natural, sendo evidenciados indícios de efeitos negativos sobre os riachos, como erosão nas margens e deposição de sedimentos finos. As variáveis que melhor explicaram a variação da fauna estão relacionadas ao porte do riacho, energia cinética de suas águas e aos tipos de substrato. Este último foi determinante para a composição das assembléias de macroinvertebrados bentônicos, pois estas variaram mais entre os tipos de substratos do que entre os sítios amostrais. A família Chironomidae foi dominante em todos os sítios e tipos de substratos. A diversidade e riqueza de família aumentaram com a estabilidade dos substratos inorgânicos / Headwater streams are relevant suppliers of water, sediment, and biota. They support low autochthonous primary productivity and suffer strong influence from riparian vegetation as in these streams the basic energy for communities maintenance has its origin in the allochthonous particulate organic matter. Hence, deforestation and inadequate soil use negatively affect stream conditions, being among the main causes of environmental degradation in developing nations. A rapid assessment of the physical habitat quality can provide a general idea about stream conditions and detect anthropic changes in a rapid, easy and low cost manner. The combination of this tool with the assessment of other physical, chemical and biological features, especially the benthic macroinvertebrate assemblage composition, is essential to the development of monitoring strategies in those ecosystems. The general aim of this study was to identify the main anthropic changes on streams of Environmental Protection Area Embu Verde and to select those with better habitat conditions for benthic fauna. So it would be possible to know the assemblages composition and its relation with the habitat. First we evaluated 23 sampling sites using a Habitat Assessment Protocol and some relevant variables. Therewith we selected four streams, grounded primarily on the similarity of the surroundings features, little variation on the environmental degradation level and potential of habitats to macroinvertebrates. Then we made an assessment of stream riparian vegetation and substrate types to improve the understanding of the relation between macroinvertebrates and the physical environment. The major anthropic change in the sampling area is the deforestation of the natural riparian cover, and we observed evidences of its negative effects on streams, as bank erosion and fine sediment deposition. Variables that better explained fauna variations are related to the stream size, water kinetic energy and substrate types. Substrate was determinant to the composition of benthic macroinvertebrate assemblages as these ones variate more with the substrates types than with the sampling sites. Chironomidae dominated in all the sampling sites and substrate types. Family diversity and richness increased with the stability of inorganic substrates

Made available in DSpace on 2017-07-10T14:38:29Z (GMT). No. of bitstreams: 1 Liliane - corrigida.pdf: 1735621 bytes, checksum: 9e277642042840851fc3ac2d9dacd470 (MD5) Previous issue date: 2015-02-23 / Fundação Araucária / This work aimed to evaluate the influence of the riparian vegetation of Santa Maria Biodiversity Corridor on the structure and composition of the phytoplankton community, comparing two streams with different levels of riparian preservation: Apepu stream and Tenente João Gualberto stream. Samples were monthly collected, between September 2012 and August 2013. As a result, 371 taxa were identified, mainly benthic and periphytic taxa, belonging to the Classes Diatomeae and Euglenophyceae. An increase in the features density and species richness was observed from the Apepu stream (greater riparian bank) to the Tenente João Gualberto stream (smaller riparian bank. This fact may have been influenced by the shading caused by the riparian forest of station 1, since the nutrients concentrations of both environments were practically the same. However, despite showing lower values in the ecological attributes, Apepu stream presented a greater stability in the features and structure of the phytoplanktonic community during the study period. Besides, the greater equitability and similarity found in the first station indicate a greater homogeneity, when compared to Tenente João Gualberto stream. In summary, it was possible to demonstrate the importance of the riparian vegetation of Santa Maria Biodiversity Corridor for the stability of the phytoplanktonic community. / Este trabalho objetivou avaliar a influência da vegetação ciliar do Corredor de Biodiversidade Santa Maria na composição e estrutura da comunidade fitoplanctônica, comparando-se dois riachos com diferentes níveis de preservação ciliar: riacho Apepu (25º30'40.5"S 54º20'31.9"W) e Tenente João Gualberto (25º28'36.3"S 54º19'40.9"W). Amostras foram coletadas mensalmente, entre setembro de 2012 e agosto de 2013. Foram identificados 371 táxons, principalmente táxons bentônicos e perifíticos das classes Diatomeae e Euglenophyceae. Foi observado um aumento dos atributos densidade e riqueza de espécies a partir da estação com maior margem ripária (Apepu) para a estação com menor margem ripária (Tenente João Gualberto). Este fato pode ter sido influenciado pelo sombreamento causado pela mata ciliar na primeira estação, já que as concentrações de nutrientes foram pouco diferentes entre os ambientes estudados. No entanto, apesar de apresentar menores valores nos atributos ecológicos, o riacho Apepu apresentou maior estabilidade na estrutura e atributos da comunidade fitoplanctônica durante o período de estudo. Além disto, a maior equitabilidade e semelhança observadas neste estação, indicam maior homogeneidade, quando comparada com o riacho Tenente João Gualberto. Em síntese, foi possível demonstrar a importância da vegetação ripária do Corredor de Biodiversidade Santa Maria para a estabilidade da comunidade fitoplanctônica.

<p>Effekterna på öringens (Salmo trutta) diet till följd av en avverkning av kantzonsvegetationen har undersökts i ett fältexperiment, där två av de potentiella effekterna av en skogsavverkning simulerades. Fokus låg på de två faktorerna ökad ljusinstrålning och minskat nedfall av terrestra evertebrater. Ökad ljusinstrålning har simulerats med hjälp av montage av lysrör och nedfall av terrestra evertebrater med hjälp av plasttält. Frågeställningarna rör andelen terrester föda i olika behandlingar och årstider, dietskillnader mellan äldre och yngre öringindivider, skillnader i mängden akvatisk föda vid ökad ljusinstrålning samt en taxonomisk översikt av dietens sammansättning. Signifikanta skillnader mellan behandlingarna fanns, där individerna i kontrollbehandlingen åt signifikant mer terrester föda än individer i tältbehandlingen och den kombinerade tält- och ljusbehandlingen. Signifikanta skillnader fanns även mellan provtagningstillfällena där en högre andel terrester föda återfinns senare på säsongen. Inga signifikanta skillnader fanns med avseende på andelen terrester föda mellan äldre och yngre individer, ej heller mellan mängd akvatisk föda mellan de olika behandlingarna. Den akvatiska födan var mer varierad och divers än den terrestra, och daggmaskar (Lumbriculidae) var en mycket vanlig födopartikel.</p> / <p>The effects on the diet of brown trout (Salmo trutta) of a clear cutting of the riparian vegetation has been investigated in a field-experiment, where two of the potential effects of a clear cut were simulated. The focus was placed on the two factors increased light and input of terrestrial invertebrates. The increase of ligth was manipulated by placing fluorescent lights over the brook and the input of terrestrial invertebrates was manipulated by placing plastic tents over the brook. Issues discussed are the percentage terrestrial food in the different treatments and at the different times of sampling, differences in the percentage terrestrial food between older and younger individuals of brown trout, differences in the amount of aquatic food in the light-treatment and a taxonomic summary of the composition of the diet. There were significant differences between the the different treatments, where the individuals in the control treatment ate significantly more terrestrial food as compared to the individuals in the tent and in the combined light and tent treatment. There was also a significant difference between the different times of sampling, more terrestrial food was consumed later in the season. No sigificant differences were detected between older and younger individuals concerning the percentage of terrestrial food eaten, nor between the different treatments concearning the amount of aquatic food consumed. The aquatic food showed a wider variation and was more diverse as compared to the terrestrial food, and earthworms (Lumbriculidae) was a very common food item.</p>

Effekterna på öringens (Salmo trutta) diet till följd av en avverkning av kantzonsvegetationen har undersökts i ett fältexperiment, där två av de potentiella effekterna av en skogsavverkning simulerades. Fokus låg på de två faktorerna ökad ljusinstrålning och minskat nedfall av terrestra evertebrater. Ökad ljusinstrålning har simulerats med hjälp av montage av lysrör och nedfall av terrestra evertebrater med hjälp av plasttält. Frågeställningarna rör andelen terrester föda i olika behandlingar och årstider, dietskillnader mellan äldre och yngre öringindivider, skillnader i mängden akvatisk föda vid ökad ljusinstrålning samt en taxonomisk översikt av dietens sammansättning. Signifikanta skillnader mellan behandlingarna fanns, där individerna i kontrollbehandlingen åt signifikant mer terrester föda än individer i tältbehandlingen och den kombinerade tält- och ljusbehandlingen. Signifikanta skillnader fanns även mellan provtagningstillfällena där en högre andel terrester föda återfinns senare på säsongen. Inga signifikanta skillnader fanns med avseende på andelen terrester föda mellan äldre och yngre individer, ej heller mellan mängd akvatisk föda mellan de olika behandlingarna. Den akvatiska födan var mer varierad och divers än den terrestra, och daggmaskar (Lumbriculidae) var en mycket vanlig födopartikel. / The effects on the diet of brown trout (Salmo trutta) of a clear cutting of the riparian vegetation has been investigated in a field-experiment, where two of the potential effects of a clear cut were simulated. The focus was placed on the two factors increased light and input of terrestrial invertebrates. The increase of ligth was manipulated by placing fluorescent lights over the brook and the input of terrestrial invertebrates was manipulated by placing plastic tents over the brook. Issues discussed are the percentage terrestrial food in the different treatments and at the different times of sampling, differences in the percentage terrestrial food between older and younger individuals of brown trout, differences in the amount of aquatic food in the light-treatment and a taxonomic summary of the composition of the diet. There were significant differences between the the different treatments, where the individuals in the control treatment ate significantly more terrestrial food as compared to the individuals in the tent and in the combined light and tent treatment. There was also a significant difference between the different times of sampling, more terrestrial food was consumed later in the season. No sigificant differences were detected between older and younger individuals concerning the percentage of terrestrial food eaten, nor between the different treatments concearning the amount of aquatic food consumed. The aquatic food showed a wider variation and was more diverse as compared to the terrestrial food, and earthworms (Lumbriculidae) was a very common food item.

What drives species diversity across landscapes is one of the most fundamental questions in ecology. Further, understanding the mechanisms underlying species diversity patterns is important not only for forming and challenging ecological theories but also essential for appropriate landscape management and effective nature conservation. This thesis focuses on patterns of vascular plant, moss and liverwort species richness and composition in relation to water flow in boreal-forest catchments, focusing mostly on riparian zones (RZs), that is terrestrial areas bordering streams and rivers. I addressed some of the most essential questions related to the ecology of riparian vegetation including the role of stream network position, groundwater (GW) flow paths, substrate availability, upland perturbations, and stream restoration. I also investigated how riparian soil processes and habitat properties relate to these factors in order to provide a holistic understanding of riparian dynamics. The results showed that the species richness and composition of riparian vascular plants, mosses and liverworts are strongly influenced by position along the stream network, GW discharge, presence of variable substrates in RZs, and by stream restoration. Generally, more species were found downstream in the network, at sites with inputs of upland GW, sites with high diversity of substrates (e.g., open mineral soil, rocks, stones, wood and bark), and along streams restored after channelization. This thesis also describes how riparian habitat properties responded to position in the landscape and human impacts, thus providing mechanistic links between plant species diversity and riparian processes across spatial scales. These ecological insights are further implemented into numerous recommendations for freshwater and upland management in boreal Sweden. Given that streams and rivers connect landscape elements both longitudinally and laterally I argue that management plans should be designed for entire catchments instead of individual river segments. Ignoring the connectivity of streams as well as the high connectivity of riparian areas to uplands via GW flows may result in failure of restoration, mitigation and/or protection actions. Further, during forestry operations more emphasis should be placed on GW discharge areas along streams and rivers, because they represent important ecological and biogeochemical hotspots in the landscape. The riparian buffers left along streams in boreal catchments affected by forestry are presently insufficiently wide and often uniform in width. This threatens the assemblages of species in GW discharge hotspots and the ecosystem services they provide. Overall, this thesis describes a holistic picture of riparian diversity patterns and riparian processes in boreal landscapes, acknowledges and elaborates on current ecological theories, presenting new patterns in biodiversity, and offers management guidelines.

Made available in DSpace on 2014-06-11T19:35:43Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-06-02Bitstream added on 2014-06-13T20:46:50Z : No. of bitstreams: 1 souza_up_dr_rcla.pdf: 976950 bytes, checksum: b3702264109c8e9210e947b1e4df6b90 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O objetivo geral do presente estudo foi analisar a biologia e o ciclo de vida de Astyanax cf. scabripinnis paranae no ribeirão Grande, um riacho de cabeceira localizado no Parque Estadual da Serra do Mar (PESM), Núcleo Santa Virgínia, SP. Os exemplares foram coletados mensalmente de janeiro a dezembro em 2004 e 2006, utilizando-se redes de espera, redinha de mão e covo. Foram coletados dados de temperatura da água, oxigênio dissolvido e pH. Dados de pluviosidade, umidade relativa e temperatura do ar foram obtidos junto à Estação Meteorológica do PESM. Os peixes foram fixados em formalina a 10% e conservados em álcool 70%. No laboratório foram mensurados quanto ao comprimento total e padrão, peso e registrados os graus de repleção estomacal, de gordura acumulada, o sexo e os estádios de maturação gonadal. As correlações entre as variáveis ambientais e os meses de coletas foram verificadas por uma análise de componentes principais, que indicou uma separação entre períodos mais chuvosos (outubro a abril) e menos chuvosos (maio a setembro). A dieta foi analisada pelo grau de preferência alimentar. Diferenças no consumo de itens autóctones e alóctones e possíveis mudanças ontogenéticas ao longo do desenvolvimento da espécie foram verificadas por uma análise de correspondência. Para o estudo da reprodução foram analisadas as variações nos estádios de maturação, relação gonadossomática, grau de gordura acumulada, condição corporal, fecundidade e tipo de desova. O comprimento médio de primeira maturação gonadal foi estimado pelo ajuste não-linear e a condição corporal foi avaliada por modelos de análise de covariância. A fecundidade foi estimada pelo método volumétrico e relacionada ao comprimento padrão, ao peso total, ao peso das gônadas e à relação gonadossomática. No estudo do crescimento, a separação das coortes... / The present study aimed to analyze the biology and ecology of Astyanax cf. scabripinnis paranae in the Ribeirão Grande, a headwater stream located in the Parque Estadual da Serra do Mar (PESM), Núcleo Santa Virgínia, SP. The fishes were sampled monthly from January to December in 2004 and 2006, using gillnets, sieves and funnel traps. Temperature, dissolved oxygen and pH of the water were measured. Pluviometric data, relative humidity and temperature of the air were obtained in the Meteorological Station of PESM. The fishes were fixed in 10% formalin and conserved in 70% alcohol. In the laboratory they were measured as for the total and standard length, weighed and registered the degrees of stomach repletion, of accumulated fat, the sex and the stadiums of gonad maturation. The correlation structure among the environmental variables measured in the sampling collections was verified by a principal components analysis (PCA), which indicated a separation among rainier (October to April) and the less rainy periods (May to September). Differences in the consumption of autochthonous and allochthonous items and possible ontogenetic changes along the specimens development were verified by a correspondence analysis (CA). For the study of the reproduction the variations were analyzed at the maturation stadiums, gonadossomatic relationship, degrees of accumulated fat, corporal condition, fecundity and spawning type. The mean length of first gonad maturation was assessed by a no-linear adjustment. The corporal condition was evaluated by analysis of covariance. The fecundity was estimate by the volumetric method and related to the standard length, to the total weight, to the gonad weight and to the gonadossomatic relationship. In the study of the fish growth, the cohorts’ separation and their mean lengths were obtained using the package MIXDIST and the Bhattacharya method... (Complete abstract click electronic access below)