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

Conselho Nacional de Desenvolvimento Científico e Tecnológico / The work was developed to recognize farmers profiles living in Ibirapuitã s Environmental Protection Area (Ibirapuitã s EPA) and identifies characteristics guiding management decisions and their social reproduction. Evaluation of the use of functional types based on grasses was also considered as an alternative to guide decision making considering appropriate management and sustainable development of areas of native grasslands. The work is divided into two approaches. The first is to collect data through semi-structured interviews, in production units located in Alegrete, Rosário do Sul and Santana do Livramento, within the Ibirapuitã s EPA. Data were tabulated in an Excel spreadsheet and multivariate analysis was performed to determine ranchers profiles in the area. Cluster analysis showed three basic profiles: familiar farmers, specialized familiar farmers and enterprise ranchers . All produce cattle and sheep on natural pasture. Through ordination analysis, we determined socioeconomic and cultural characteristics that influence in management of natural resources. In the second approach were conducted four assessments of the floristic composition in Alegrete municipality in October 2008, April 2009, October 2009 and January 2010. In all evaluations were performed to determine the specific leaf area (SLA) and dry matter content (LDMC) of grasses with the greater contribution in forage mass. Data relating to botanical survey were analyzed using software MULTIV. SLA and LDMC collected data were analyzed together with the same attributes already determined in Santa Maria and Bagé, where functional types had already been determined by testing the factors grazing, burning, fertilization, site and functional types. We performed multivariate analysis using the software MULTIV. Variation of herbage mass of botanical families in the evaluated area was relevant to management compared with total variation in herbage mass. The grazing factor allowed the selection of species of types A and B over the species conservation of resources types C and D. The use of functional types of grasses can be extended to other regions like the West Border of the RS by the consistency showed that the functional attributes. / A dissertação foi desenvolvida objetivando reconhecer os perfis dos pecuaristas que vivem na Área de Proteção Ambiental do Rio Ibirapuitã e identificar caracteríticas que podem nortear suas decisões de manejo e reprodução social. Também foi considerada avaliação do uso dos tipos funcionais baseados em gramíneas como alternativa para orientar as tomadas de decisão quanto ao manejo adequado e sustentável das áreas de campo nativo. O trabalho está dividido em duas abordagens. A primeira consiste na coleta de dados, por meio de entrevistas semiestruturadas, em unidades produtivas localizadas em Alegrete, Rosário do Sul e Santana do Livramento, dentro da Área de Proteção Ambiental do Rio Ibirapuitã. Os dados foram tabulados em planilha Excel e foi realizada análise multivariada para determinar os perfis de pecuaristas existentes na área. A análise de agrupamento apresentou três perfis básicos: pecuaristas familiares, pecuaristas familiares especializados e pecuaristas empresariais. Todos produzem bovinos e ovinos em pastagem natural. Por meio da análise de ordenação foi possível constatar que as características sócio-econômicas e culturais influenciam no manejo dos recursos naturais. Na segunda abordagem, foram realizadas quatro avaliações da composição florística no município de Alegrete, em outubro de 2008, abril de 2009, outubro de 2009 e janeiro de 2010. Em todas as avaliações foi realizada a determinação da área foliar específica (AFE) e teor de matéria seca (TMS) das gramíneas com contribuição majoritária na massa de forragem. Os dados referentes ao levantamento botânico foram analisados utilizando software MULTIV. A AFE e o TMS determinados no presente trabalho foram analisados conjuntamente com os mesmos atributos já determinados nos municípios de Santa Maria e Bagé onde os tipos funcionais já haviam sido determinados, testando os fatores pastejo, queima, adubação, local e tipos funcionais. Foi realizada análise estatística multivariada utilizando o software MULTIV. A variação da massa de forragem das famílias botânicas na área avaliada foi relevante para o manejo em comparação a variação da massa de forragem total. O fator pastejo permitiu a seleção de espécies dos tipos A e B, em detrimento às espécies de conservação de recursos dos tipos C e D. O uso dos tipos funcionais de gramíneas pode ser extendido para outras regiões, como a Fronteira Oeste do RS pela consistência que os atributos funcionais apresentaram.

O conceito de ‘ecossistema’ emergiu da necessidade de compreender o caráter extremamente dinâmico da vegetação, interpretado a partir daí como o resultado da interação recíproca entre um dado complexo de organismos e seu conjunto amplo de fatores do ambiente físico. Um ramo das ciências ecológicas desenvolveu-se desse conceito, visando examinar o resultado de tais interações em termos de fluxos de energia, matéria e informação. Desenvolvimentos conceituais recentes apontam para uma concepção do ecossistema sob a ótica de um novo paradigma, para o qual aninhamento, hierarquia, decomposabilidade relativa, probabilidade e dependência de escala são critérios chave. Outro desenvolvimento importante, a análise de trajetórias, abriu a possibilidade de tratar a dinâmica e o funcionamento do ecossistema como fenômenos em múltiplas escalas. Incertezas metodológicas e ecológicas decorrem numa visão pouco nítida de como o funcionamento e a estrutura do ecossistema interagem sob a influência de um determinado conjunto de fatores de uso e do ambiente físico. A situação demanda uma abordagem analítica na qual classificações funcionais e estruturais sejam implementadas independentemente, com o fim de estabelecer ‘a posteriori’ quanto e como as classificações estão interconectadas. A tarefa é ainda mais desafiante, em termos de método e interpretação, quando consideramos o contexto hierárquico e complexo em que a análise deve ser feita e a dependência de definição dos resultados. Esta tese refere-se ao desenvolvimento de ferramentas conceituais e metodológicas para analisar a heterogeneidade funcional dos ecossistemas no espaço, em relação a fatores significativos de uso e do ambiente, e aos diferentes tipos de vegetação presentes numa determinada região. Com esse objetivo, adotamos o conceito de ‘Tipos Funcionais de Ecossistemas’ (TFEs), os quais reúnem unidades espaciais com padrão de funcionamento similar, sem considerar seus atributos estruturais, e avançamos num esquema classificatório de TFEs que permite capturar as respostas funcionais de curto prazo dos ecossistemas em cenários de mudanças ambientais e de uso altamente dinâmicas. Também examinamos a sensibilidade dos tipos funcionais de ecossistemas a diferentes definições de funcionamento e parâmetros de escala espacial. Os TFEs provaram ser sensíveis a estas variáveis analíticas, oferecendo assim a possibilidade de indagar a natureza multidimensional e multi-escala dos fenômenos do ecossistema. Os TFEs capturam eficientemente os aspectos mais relevantes da resposta sazonal da vegetação aos fatores do ambiente biofísico, provendo assim uma ferramenta útil para descrever a heterogeneidade espacial do funcionamento dos ecossistemas em domínios temporais e geográficos específicos. Nesta tese avançamos no reconhecimento e descrição dos principais tipos de paisagem no planalto basáltico do Rio Grande do Sul, e propomos mecanismos e controles responsáveis desses padrões característicos. Da associação espacial entre feições do terreno, solos, tipos de uso e vegetação, identificamos três tipos básicos de paisagens e definimos preliminarmente seu domínio espacial. Os resultados descrevem um forte relacionamento entre a distribuição dos grandes tipos fisionômicos de vegetação, os solos e os processos formadores de relevo. Assim sendo, os campos dominam onde relevo e solos indicam a ocorrência de remanescentes de uma antiga superfície de pediplanação, em quanto as florestas prevalecem onde os agentes geomorfológicos têm rejuvenescido a paisagem. Porém, com o objetivo de compreender os processos responsáveis destes padrões, é essencial fazer ‘downscaling’ desde a escala regional na qual os processos formadores de relevo e de solos dominam a diferenciação espacial de variáveis ecológicas, até a escala local na qual fatores biológicos e relacionados com o regime de distúrbio adquirem maior importância na produção de padrões de heterogeneidade espacial. Identificamos que a abordagem ecossistêmica funcional é a maneira mais promissora de relacionar processos de natureza tão divergente. / The ‘ecosystem’ concept emerged from the need for understanding the highly dynamic nature of the vegetation, interpreted from thereon as the reciprocal interaction among the organism-complex and a wide array of factors of the physical environment. A full branch of the ecological sciences developed from this concept, aimed to assessing the outcome of such interactions as flows of energy, matter and information. Recent conceptual developments points to a conception of ecosystem as an entity evolving under the influence of a novel paradigm, for which nestedness, hierarchy, relative decomposability, probability and scale-dependency are central. Another important development, trajectory analysis, opens the possibility to treat ecosystem dynamics and ecosystem functioning as multi-scale phenomena. Methodological and ecological uncertainties determine a rather fuzzy picture of how ecosystem function and structure interplay under the influence of some set of drivers of the physical environment and land use. The whole situation waits for an analytical path to be designed in which functional and structural classifications are carried out independently, in order to establish a posteriori whether they are connected and how they are connected. The task is even more defiant, both in terms of methods and interpretation, if we consider the already complex hierarchical context in which the analysis should be set and the definition-dependency of the outcome. This thesis is about the development of conceptual and analytical tools for analyzing the functional heterogeneity of the ecosystems in the space, in relation to meaningful environmental and land-use factors and to the different types of vegetation present over a given region. To that aim, we adopt the concept of Ecosystem Functional Types (EFTs), which enclose spatial units with similar functional patterns, no attention paid to their structure, and advance on an EFT classificatory scheme that allows capturing the short-term functional response of the ecosystems to environmental and land-use changes. Furthermore, we examine the effect of using different surrogates of ecosystem functioning on the resulting picture of functional patchiness. The effect of changing parameters of spatial scale is also tested. The Ecosystem Functional Types proved to be heavily definition-dependent and sensitive to spatial scale, which allows exploring the multi-dimensional and multi-scale nature of ecosystem phenomena. The EFTs efficiently capture the most relevant features of the seasonal response of the vegetation to the drivers of the biophysical environment, providing so a useful tool for depicting the spatial heterogeneity of ecosystem functioning in a given geographic and temporal domain. In this report we also accomplished the recognition and description of main landscape types in the basaltic tablelands of Rio Grande do Sul, and proposed mechanisms and controls responsible for their characteristic patterns. From the spatial association of terrain features, soils, land-use and vegetation, we identified three basic landscape types and broadly defined their spatial domain. The picture described tells of a rather close relationship among the distribution of the major physiognomic types of the vegetation, soils, land-use and land-forming processes. In this picture, the grasslands prevail where terrain and soil features suggest there are the remnants of an old pediplanation surface, while forests seems to dominate wherever geomorphic agents have rejuvenated the landscape. However, in order to understand the processes responsible of these patterns it is then essential to downscale from the regional realm where terrain and soil-forming phenomena dominate spatial differentiation, to the fine-scale processes at which biological and disturbance-related factors are most influential in the production of patterns of spatial heterogeneity. We identify the functional approach to the ecosystems as the most promising way to correlate processes of such a different nature.

The development of economically viable production systems, which can make compatible good beef cattle profit and the preservation of natural grassland ecosystems, should be supported by knowledge of dynamic of vegetation that occur after some management practices. Vegetation dynamic studies show the existence of populations replacement processes which can be observed in space and time, in different scales. Modeling these systems would be one alternative to achieve this premise. To achieve this purpose, this thesis, is divided in two chapters. In the are presented, respectively, temporal dynamics of grasslands vegetation, based on species composition (taxons) or Plants´ Functional Types (PFT) groups. These were based on the traits: Specific Leaf Area (SLA) e Leaf Dry Matter Content (LDM), which grouped Poaceae family species in four groups (A, B, C and D). Data used in this thesis came from vegetation relévés from 1995 to 2001, and data predict by Markov chains. Typical disturbance factors of grassland vegetation, grazing and burning, and their interactions, combined with relief position, express the scenarios which should be modeled along the time. Results obtained by using ordination and randomization analysis show that is possible using this tool to build up predictive models of vegetation composition in grassland areas, independently from the evaluation being based on taxons or PFT. When it was based in taxons, a certain degree of imprecision in the estimation of forage mass of species with a low initial contribution. Grazing and relief position were determinant of ordination trajectory, and that was not possible to identify in burning. When based in PFTs, results obtained from model validation, from ordination analysis and from randomization tests, showed a tendency of trajectories and of predicted values of functional groups, which is more suitable for plots under grazing. Using this model, as a management tool for areas under grazing, is in dependence of new validation researches, using new data, but for this is necessary to make strong the exchange of informations among research groups in this area. / O desenvolvimento de sistemas de produção viáveis economicamente, que tornem compatíveis bons ganhos animais com a preservação dos ecossistemas de pastagens naturais, deve ser apoiado pelo conhecimento da dinâmica da vegetação que ocorre após determinadas práticas de manejo. Estudos de dinâmica da vegetação revelam processos de substituição de populações, que podem ser observados no espaço e no tempo, em diferentes escalas. A modelagem destes sistemas pode representar uma alternativa para revelar esses processos. Deste modo, a presente tese, está dividida em dois capítulos, sendo abordadas, respectivamente, as dinâmicas temporais da vegetação, baseadas na composição de espécies da área (Táxons) ou dos grupos de Tipos Funcionais de Plantas (TFP). Estes foram baseados nos atributos Área Foliar Específica (AFE) e Teor de Matéria Seca Foliar (TMS), os quais agruparam as espécies pertencentes à família Poaceae, em quatro grupos (A, B, C e D). Os dados utilizados nesta tese foram procedentes de inventários da vegetação, dos anos de 1995 a 2001, e de matrizes de transição das Cadeias de Markov. Os fatores pastejo e queima, e suas interações, combinados com as posições de relevo, foram os fatores de distúrbio que expressam os cenários a serem modelados no tempo. Os resultados obtidos através das análises de ordenação e aleatorização demonstram a aplicabilidade das Cadeias de Markov na construção de modelos preditivos da composição da vegetação em áreas campestres, independentemente da avaliação ser baseada em Taxóns ou TFP. Quando a avaliação foi realizada com base em Táxons, houve certa imprecisão na estimativa de valores de massa de forragem das espécies com baixa contribuição inicial. Os fatores pastejo e posição topográfica apresentaram-se como determinantes das trajetórias de ordenação, o que não foi identificado para o fator queima. Com relação aos TFP, os resultados obtidos na validação do modelo, através das análises de ordenação e aleatorização, indicam uma tendência das trajetórias e dos valores preditos para grupos de TFP, serem mais adequados para as parcelas sobre influencia de pastejo. A difusão deste modelo, como ferramenta de manejo das áreas sobre pastejo, depende ainda de novas validações, utilizandose novos grupos de dados, para isso se torna necessário o fortalecimento do intercâmbio de informações entre os grupos de pesquisa nesta área.

O conceito de ‘ecossistema’ emergiu da necessidade de compreender o caráter extremamente dinâmico da vegetação, interpretado a partir daí como o resultado da interação recíproca entre um dado complexo de organismos e seu conjunto amplo de fatores do ambiente físico. Um ramo das ciências ecológicas desenvolveu-se desse conceito, visando examinar o resultado de tais interações em termos de fluxos de energia, matéria e informação. Desenvolvimentos conceituais recentes apontam para uma concepção do ecossistema sob a ótica de um novo paradigma, para o qual aninhamento, hierarquia, decomposabilidade relativa, probabilidade e dependência de escala são critérios chave. Outro desenvolvimento importante, a análise de trajetórias, abriu a possibilidade de tratar a dinâmica e o funcionamento do ecossistema como fenômenos em múltiplas escalas. Incertezas metodológicas e ecológicas decorrem numa visão pouco nítida de como o funcionamento e a estrutura do ecossistema interagem sob a influência de um determinado conjunto de fatores de uso e do ambiente físico. A situação demanda uma abordagem analítica na qual classificações funcionais e estruturais sejam implementadas independentemente, com o fim de estabelecer ‘a posteriori’ quanto e como as classificações estão interconectadas. A tarefa é ainda mais desafiante, em termos de método e interpretação, quando consideramos o contexto hierárquico e complexo em que a análise deve ser feita e a dependência de definição dos resultados. Esta tese refere-se ao desenvolvimento de ferramentas conceituais e metodológicas para analisar a heterogeneidade funcional dos ecossistemas no espaço, em relação a fatores significativos de uso e do ambiente, e aos diferentes tipos de vegetação presentes numa determinada região. Com esse objetivo, adotamos o conceito de ‘Tipos Funcionais de Ecossistemas’ (TFEs), os quais reúnem unidades espaciais com padrão de funcionamento similar, sem considerar seus atributos estruturais, e avançamos num esquema classificatório de TFEs que permite capturar as respostas funcionais de curto prazo dos ecossistemas em cenários de mudanças ambientais e de uso altamente dinâmicas. Também examinamos a sensibilidade dos tipos funcionais de ecossistemas a diferentes definições de funcionamento e parâmetros de escala espacial. Os TFEs provaram ser sensíveis a estas variáveis analíticas, oferecendo assim a possibilidade de indagar a natureza multidimensional e multi-escala dos fenômenos do ecossistema. Os TFEs capturam eficientemente os aspectos mais relevantes da resposta sazonal da vegetação aos fatores do ambiente biofísico, provendo assim uma ferramenta útil para descrever a heterogeneidade espacial do funcionamento dos ecossistemas em domínios temporais e geográficos específicos. Nesta tese avançamos no reconhecimento e descrição dos principais tipos de paisagem no planalto basáltico do Rio Grande do Sul, e propomos mecanismos e controles responsáveis desses padrões característicos. Da associação espacial entre feições do terreno, solos, tipos de uso e vegetação, identificamos três tipos básicos de paisagens e definimos preliminarmente seu domínio espacial. Os resultados descrevem um forte relacionamento entre a distribuição dos grandes tipos fisionômicos de vegetação, os solos e os processos formadores de relevo. Assim sendo, os campos dominam onde relevo e solos indicam a ocorrência de remanescentes de uma antiga superfície de pediplanação, em quanto as florestas prevalecem onde os agentes geomorfológicos têm rejuvenescido a paisagem. Porém, com o objetivo de compreender os processos responsáveis destes padrões, é essencial fazer ‘downscaling’ desde a escala regional na qual os processos formadores de relevo e de solos dominam a diferenciação espacial de variáveis ecológicas, até a escala local na qual fatores biológicos e relacionados com o regime de distúrbio adquirem maior importância na produção de padrões de heterogeneidade espacial. Identificamos que a abordagem ecossistêmica funcional é a maneira mais promissora de relacionar processos de natureza tão divergente. / The ‘ecosystem’ concept emerged from the need for understanding the highly dynamic nature of the vegetation, interpreted from thereon as the reciprocal interaction among the organism-complex and a wide array of factors of the physical environment. A full branch of the ecological sciences developed from this concept, aimed to assessing the outcome of such interactions as flows of energy, matter and information. Recent conceptual developments points to a conception of ecosystem as an entity evolving under the influence of a novel paradigm, for which nestedness, hierarchy, relative decomposability, probability and scale-dependency are central. Another important development, trajectory analysis, opens the possibility to treat ecosystem dynamics and ecosystem functioning as multi-scale phenomena. Methodological and ecological uncertainties determine a rather fuzzy picture of how ecosystem function and structure interplay under the influence of some set of drivers of the physical environment and land use. The whole situation waits for an analytical path to be designed in which functional and structural classifications are carried out independently, in order to establish a posteriori whether they are connected and how they are connected. The task is even more defiant, both in terms of methods and interpretation, if we consider the already complex hierarchical context in which the analysis should be set and the definition-dependency of the outcome. This thesis is about the development of conceptual and analytical tools for analyzing the functional heterogeneity of the ecosystems in the space, in relation to meaningful environmental and land-use factors and to the different types of vegetation present over a given region. To that aim, we adopt the concept of Ecosystem Functional Types (EFTs), which enclose spatial units with similar functional patterns, no attention paid to their structure, and advance on an EFT classificatory scheme that allows capturing the short-term functional response of the ecosystems to environmental and land-use changes. Furthermore, we examine the effect of using different surrogates of ecosystem functioning on the resulting picture of functional patchiness. The effect of changing parameters of spatial scale is also tested. The Ecosystem Functional Types proved to be heavily definition-dependent and sensitive to spatial scale, which allows exploring the multi-dimensional and multi-scale nature of ecosystem phenomena. The EFTs efficiently capture the most relevant features of the seasonal response of the vegetation to the drivers of the biophysical environment, providing so a useful tool for depicting the spatial heterogeneity of ecosystem functioning in a given geographic and temporal domain. In this report we also accomplished the recognition and description of main landscape types in the basaltic tablelands of Rio Grande do Sul, and proposed mechanisms and controls responsible for their characteristic patterns. From the spatial association of terrain features, soils, land-use and vegetation, we identified three basic landscape types and broadly defined their spatial domain. The picture described tells of a rather close relationship among the distribution of the major physiognomic types of the vegetation, soils, land-use and land-forming processes. In this picture, the grasslands prevail where terrain and soil features suggest there are the remnants of an old pediplanation surface, while forests seems to dominate wherever geomorphic agents have rejuvenated the landscape. However, in order to understand the processes responsible of these patterns it is then essential to downscale from the regional realm where terrain and soil-forming phenomena dominate spatial differentiation, to the fine-scale processes at which biological and disturbance-related factors are most influential in the production of patterns of spatial heterogeneity. We identify the functional approach to the ecosystems as the most promising way to correlate processes of such a different nature.

O conceito de ‘ecossistema’ emergiu da necessidade de compreender o caráter extremamente dinâmico da vegetação, interpretado a partir daí como o resultado da interação recíproca entre um dado complexo de organismos e seu conjunto amplo de fatores do ambiente físico. Um ramo das ciências ecológicas desenvolveu-se desse conceito, visando examinar o resultado de tais interações em termos de fluxos de energia, matéria e informação. Desenvolvimentos conceituais recentes apontam para uma concepção do ecossistema sob a ótica de um novo paradigma, para o qual aninhamento, hierarquia, decomposabilidade relativa, probabilidade e dependência de escala são critérios chave. Outro desenvolvimento importante, a análise de trajetórias, abriu a possibilidade de tratar a dinâmica e o funcionamento do ecossistema como fenômenos em múltiplas escalas. Incertezas metodológicas e ecológicas decorrem numa visão pouco nítida de como o funcionamento e a estrutura do ecossistema interagem sob a influência de um determinado conjunto de fatores de uso e do ambiente físico. A situação demanda uma abordagem analítica na qual classificações funcionais e estruturais sejam implementadas independentemente, com o fim de estabelecer ‘a posteriori’ quanto e como as classificações estão interconectadas. A tarefa é ainda mais desafiante, em termos de método e interpretação, quando consideramos o contexto hierárquico e complexo em que a análise deve ser feita e a dependência de definição dos resultados. Esta tese refere-se ao desenvolvimento de ferramentas conceituais e metodológicas para analisar a heterogeneidade funcional dos ecossistemas no espaço, em relação a fatores significativos de uso e do ambiente, e aos diferentes tipos de vegetação presentes numa determinada região. Com esse objetivo, adotamos o conceito de ‘Tipos Funcionais de Ecossistemas’ (TFEs), os quais reúnem unidades espaciais com padrão de funcionamento similar, sem considerar seus atributos estruturais, e avançamos num esquema classificatório de TFEs que permite capturar as respostas funcionais de curto prazo dos ecossistemas em cenários de mudanças ambientais e de uso altamente dinâmicas. Também examinamos a sensibilidade dos tipos funcionais de ecossistemas a diferentes definições de funcionamento e parâmetros de escala espacial. Os TFEs provaram ser sensíveis a estas variáveis analíticas, oferecendo assim a possibilidade de indagar a natureza multidimensional e multi-escala dos fenômenos do ecossistema. Os TFEs capturam eficientemente os aspectos mais relevantes da resposta sazonal da vegetação aos fatores do ambiente biofísico, provendo assim uma ferramenta útil para descrever a heterogeneidade espacial do funcionamento dos ecossistemas em domínios temporais e geográficos específicos. Nesta tese avançamos no reconhecimento e descrição dos principais tipos de paisagem no planalto basáltico do Rio Grande do Sul, e propomos mecanismos e controles responsáveis desses padrões característicos. Da associação espacial entre feições do terreno, solos, tipos de uso e vegetação, identificamos três tipos básicos de paisagens e definimos preliminarmente seu domínio espacial. Os resultados descrevem um forte relacionamento entre a distribuição dos grandes tipos fisionômicos de vegetação, os solos e os processos formadores de relevo. Assim sendo, os campos dominam onde relevo e solos indicam a ocorrência de remanescentes de uma antiga superfície de pediplanação, em quanto as florestas prevalecem onde os agentes geomorfológicos têm rejuvenescido a paisagem. Porém, com o objetivo de compreender os processos responsáveis destes padrões, é essencial fazer ‘downscaling’ desde a escala regional na qual os processos formadores de relevo e de solos dominam a diferenciação espacial de variáveis ecológicas, até a escala local na qual fatores biológicos e relacionados com o regime de distúrbio adquirem maior importância na produção de padrões de heterogeneidade espacial. Identificamos que a abordagem ecossistêmica funcional é a maneira mais promissora de relacionar processos de natureza tão divergente. / The ‘ecosystem’ concept emerged from the need for understanding the highly dynamic nature of the vegetation, interpreted from thereon as the reciprocal interaction among the organism-complex and a wide array of factors of the physical environment. A full branch of the ecological sciences developed from this concept, aimed to assessing the outcome of such interactions as flows of energy, matter and information. Recent conceptual developments points to a conception of ecosystem as an entity evolving under the influence of a novel paradigm, for which nestedness, hierarchy, relative decomposability, probability and scale-dependency are central. Another important development, trajectory analysis, opens the possibility to treat ecosystem dynamics and ecosystem functioning as multi-scale phenomena. Methodological and ecological uncertainties determine a rather fuzzy picture of how ecosystem function and structure interplay under the influence of some set of drivers of the physical environment and land use. The whole situation waits for an analytical path to be designed in which functional and structural classifications are carried out independently, in order to establish a posteriori whether they are connected and how they are connected. The task is even more defiant, both in terms of methods and interpretation, if we consider the already complex hierarchical context in which the analysis should be set and the definition-dependency of the outcome. This thesis is about the development of conceptual and analytical tools for analyzing the functional heterogeneity of the ecosystems in the space, in relation to meaningful environmental and land-use factors and to the different types of vegetation present over a given region. To that aim, we adopt the concept of Ecosystem Functional Types (EFTs), which enclose spatial units with similar functional patterns, no attention paid to their structure, and advance on an EFT classificatory scheme that allows capturing the short-term functional response of the ecosystems to environmental and land-use changes. Furthermore, we examine the effect of using different surrogates of ecosystem functioning on the resulting picture of functional patchiness. The effect of changing parameters of spatial scale is also tested. The Ecosystem Functional Types proved to be heavily definition-dependent and sensitive to spatial scale, which allows exploring the multi-dimensional and multi-scale nature of ecosystem phenomena. The EFTs efficiently capture the most relevant features of the seasonal response of the vegetation to the drivers of the biophysical environment, providing so a useful tool for depicting the spatial heterogeneity of ecosystem functioning in a given geographic and temporal domain. In this report we also accomplished the recognition and description of main landscape types in the basaltic tablelands of Rio Grande do Sul, and proposed mechanisms and controls responsible for their characteristic patterns. From the spatial association of terrain features, soils, land-use and vegetation, we identified three basic landscape types and broadly defined their spatial domain. The picture described tells of a rather close relationship among the distribution of the major physiognomic types of the vegetation, soils, land-use and land-forming processes. In this picture, the grasslands prevail where terrain and soil features suggest there are the remnants of an old pediplanation surface, while forests seems to dominate wherever geomorphic agents have rejuvenated the landscape. However, in order to understand the processes responsible of these patterns it is then essential to downscale from the regional realm where terrain and soil-forming phenomena dominate spatial differentiation, to the fine-scale processes at which biological and disturbance-related factors are most influential in the production of patterns of spatial heterogeneity. We identify the functional approach to the ecosystems as the most promising way to correlate processes of such a different nature.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The impact arising from livestock activity in grassland ecosystems reflects a long history of how this activity was carried. One alternative of lasting management for conservation of these lands is to use the capacity of resilience of natural grassland, in which important tools for recovery are control of leaf defoliation and nutrient replacement. Changes in vegetation take place throughout time and space by a broad range of factors and, for their interpretation, plant s mechanisms of capture and storage of resources must be understood. Plant functional types are one approach highlighted at large scale responses. However to make this framework operational, it depends on knowledge of species development and especially their role in biomass production or in ecological processes at the landscape level. This work s hypothesis is that communities ranked into functional groups of plants may show patterns of biomass distribution along the community that are related to environmental factors and management. The experiment was conducted in livestock farms (UEPAs) enrolled in a project linked to EMBRAPA-CPPSUL established since 2008. In such UEPAs rotational grazing and natural fertilizers were applied together in natural grassland paddocks. Four surveys were conducted for assessment of species contribution on biomass since April/2012 to September/2011. Poaceae species were ranked according to its contribution in vegetation, through their morphological traits: specific leaf area and leaf dry matter content. This approach allows defining groups of species with different features even for large-scale environmental factors . Through biomass accumulation of plant groups with similar functional traits it was possible to diagnose vegetation patterns in response to environmental and management factors. / O impacto decorrente da atividade pecuária em ecossistemas campestres reflete um longo histórico da forma como essa atividade foi exercida. Para manutenção dessas áreas, uma alternativa de manejo durável é usar a capacidade de resiliência da pastagem natural, onde são partes importantes na recuperação: o controle da desfolha e a reposição de nutrientes. Mudanças na vegetação ocorrem ao longo do tempo e do espaço por uma ampla extensão de fatores e para a sua interpretação devem ser entendidos os mecanismos de captura e estocagem de recursos efetuados pela planta. A abordagem de tipos funcionais de plantas é destacada nas respostas em ampla escala, no entanto tornar esse conhecimento um quadro mais operacional depende do conhecimento do desenvolvimento das espécies e sobre tudo sua implicação na produção ou nos processos ecológicos em nível de pastagem. A hipótese deste trabalho é que as comunidades classificadas em grupos funcionais de plantas possam demonstrar padrões de configurações de biomassa na comunidade que se relacionam a fatores ambientais e de manejo. Este estudo foi realizado em estabelecimentos rurais (UEPAs) cadastradas em projeto vinculado a EMBRAPA-CPPSUL implantado a partir do ano de 2008. Nessas UEPAs foram realizados quatro inventários para determinação da composição botânica e contribuição das espécies na massa de forragem, no período de setembro/2011 a abril/2012. O manejo do pastoreio foi o rotativo e a pastagem natural recebeu aplicação de fertilizantes naturais. Na abordagem foram classificadas as espécies de Poaceae que possuem maior participação na vegetação, através de seus atributos morfológicos TMS e AFE, possibilitando agrupar espécies com diferentes características em diferentes condições ambientais. Através do acúmulo de biomassa nas comunidades de grupos de plantas com atributos funcionais semelhantes foi possível diagnosticar padrões de vegetação em resposta aos fatores ambientais e de manejo.

>Magister Scientiae - MSc / Understanding of Groundwater Dependent Ecosystems (GDEs) and their extent within the Table Mountain Group (TMG) aquifer is poor. To understand the dependence to basic ecological and hydrogeological concepts need explanation. The use of current literature aided in identification and classification. From the literature it has come clear that groundwater dependence centers around two issues, water source and water use determination. The use of Geographical Information System (GIS) showed its potential in proof of water sources. Rainfall data and a Digital Elevation Model (DEM) for the Uniondale area have been used to do watershed delineation, which is in line with locating GDEs on a landscape. Thus the conceptual approach should be a broad one that sets a basis for both investigation (scientific research) and institutional arrangements (management). On the scientific research aspect: 1) Methods used to ascertain groundwater dependence have been identified and described (for example morphological traits, physiological traits, etc.) a) Use of GIS to delineate watersheds in the Uniondale area, putting it as one of useful methods that can be used in locating GDEs in a landscape. b) Use of Digital Elevation Models (DEMs) to create both geological and topographic cross-sections. Topographic cross-sections are important to locate ecosystems along a landscape, while geological cross-sections are useful in conceptualising groundwater flow. 2) The Plant Functional Type concept, which puts together plant species regardless of phylogeny but rather on morphological, phenological and physiological/life history trait similarity, has been suggested as a useful concept for the TMG GDEs. On the management aspect: 1) An ecosystem approach to understand groundwater has been identified and modified to suite the TMG GDE management. 2) A retention strategy useful to manage the TMG GDEs effectively has been suggested. There are knowledge gaps that exist in the TMG aquifer about Groundwater Dependent Ecosystems. Thus there is: • A need to identify GDE types that exist based on their degrees of dependency on groundwater. • A need to classify the GDEs using a PFTconcept. • To compile a trait (morphological, phenological and physiological) database for TMG aquifer GDEs.

Invasive exotic plants can persist and successfully spread within ecosystems and negatively affect the recruitment of native species. The exotic invasive Ailanthus altissima and the native Robinia pseudoacacia are frequently found in disturbed sites and exhibit similar growth and reproductive characteristics, yet each has distinct functional roles such as allelopathy and nitrogen fixation, respectively. 1) A four-month full additive series in the greenhouse and 2) spatial point pattern analysis of trees in a silvicultural experiment were used to analyze the intraspecific and interspecific interference between these two species. In the greenhouse experiment, total biomass responses per plant for both species were significantly affected by interspecific but not by intraspecific interference (p <0.05). Competition indices such as Relative Yield Total and Relative Crowding Coefficient suggested that A. altissima was the better competitor in mixed plantings. Ailanthus altissima consistently produced a larger above ground and below ground relative yield while R. pseudoacacia generated a larger aboveground relative yield in high density mixed species pots. However, R. pseudoacacia exhibited more variation for multiple biomass traits, occasionally giving it an above ground advantage in some mixed species pots. Analysis of spatial point patterns in the field with Ripley's K indicated that the two species were positively associated with each other along highly disturbed skid trails in the majority of the field sites. Locally, increased disturbances could lead to more opportunities for A. altissima to invade, negatively interact with R. pseudoacacia (as was evident in the greenhouse study), and become established in place of native species. / Master of Science

Dissertation presented for the degree of Doctor of Philosophy (PhD) at Stellenbosch University. / Thesis (PhD (Conservation Ecology and Entomology))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: The South African Cape lowlands have been severely transformed and reduced to fragments embedded in matrices of various activities. With the need to prioritise conservation efforts, information on the conservation worthiness and management of these fragments is required. This study aimed to better understand how fragmentation affects the Cape lowland vegetation patterns and dynamics and more specifically, to determine if, and if so to what extent these fragments contribute to regional plant diversity and more importantly their functionality. The novel approach adopted focused on plant functional traits, which are better predictors of ecosystem response to global change than individual species. Species were sampled at four scales in four sites of decreasing sizes, including: a mainland and three fragments of three Cape lowland vegetation types i.e. Atlantis Sand Fynbos (ASF), Swartland Shale Renosterveld (SSR) and Langebaan Dune Strandveld (LDS). Traits such as dispersal, pollination, breeding mode and longevity were selected based on relevance to species’ and plantfunctional types’ (PFTs) responses to fragmentation. The findings revealed different effects on species richness and PFTs. The effect of reduced patch size on species richness was more evident in ASF where fragments below 600 ha had significantly fewer species than the mainland. This effect was not unequivocal in SSR and LDS due to several confounding factors (notably the grazing history of the sites). The SSR fragment grazed by indigenous herbivores had significantly more species than the ungrazed sites. Also, the largest LDS fragment grazed by livestock had significantly more species than the ungrazed mainland, indicating that grazing rather than fragment size influences species richness, although the smallest fragments of these two vegetation types had significantly fewer species than the larger fragments. Species turnover and complementarity were high for all three vegetation types, reflecting the degree of habitat heterogeneity and high contribution of beta diversity to overall gama diversity. The effect of reduced patch size was higher on PFT diversity than on PFT richness, with Langebaan Dune Strandveld where habitat fragmentation was more recent being the least affected of the three vegetation types. This indicates a degree of functional redundancy in the Cape lowlands, which is important for ecosystem resistance and resilience. The ASF mainland and the largest fragment had higher PFT diversity than the medium-sized and the smallest fragments; the mainland had also higher PFT diversity than all the fragments combined. Similarly, the smallest SSR fragment had significantly lower PFT diversity and richness than the other sites. The grazed SSR fragment had higher PFT richness and diversity than the ungrazed mainland and smallest fragment, indicating the role of grazing in maintaining renosterveld vegetation. The PFTs absent from the different sites were mostly short-distance dispersed dioecious and non-dioecious species, and some with highly specialised pollination systems. This suggests that dispersal and pollination are vital functional attributes for the persistence of the studied fragmented ecosystems. Habitat fragmentation effects plant community composition and ecological functions in the Cape lowlands, a conclusion supported also by the revealed significant trait-convergence and divergence assembly patterns. These communities result from various fragmentation filters that operate at different spatial-temporal scales and selecting species with suitable responses. All three vegetation types are susceptible to fragmentation, albeit at varying degree. The fragmentation effect was confounded by the sampling and temporal scales, the nature of disturbance regime, and the traitmediated differences in species’ response. The role of the surrounding matrix on fragment connectivity and gene flow appears to be of crucial importance, hence mitigation measures focusing on improving connectivity between patches, monitoring threatened taxa, and promoting dispersal and pollination have been recommended. / AFRIKAANSE OPSOMMING: Suid-Afrika se Kaapse laagland het dramaties verander en weggekwyn tot fragmente wat in matrikse van verskeie bedrywighede veranker is. Gedagtig aan die voorkeuraandag wat bewaringspogings tans geniet, is inligting oor die bewaringswaardigheid en bestuur van hierdie fragmente nodig. Hierdie studie stel dit ten doel om beter begrip te vorm van hoe fragmentasie die plantegroeipatrone en -dinamiek in die Kaapse laagland raak, en meer bepaald om vas te stel óf, en indien wel, in watter mate, hierdie fragmente tot streeksplantdiversiteit en -funksionaliteit bydra. Die ongewone studiebenadering konsentreer op funksionele kenmerke van plante, wat beter aanwyser van ekosisteemreaksie op wêreldwye verandering is as individuele spesies. Spesiemonsters is op vier skale by vier terreine van wisselende grootte ingesamel, wat insluit moederstrook en drie fragmente van elk van drie plantegroeisoorte in die Kaapse laagland, naamlik Atlantis-sandfynbos (ASF), Swartland-skalierenosterveld (SSR) en Langebaan-duinestrandveld (LDS). Kenmerke soos verspreiding, bestuiwing, voortplantingsmetode en lewensduur is gekies op grond van die tersaaklikheid daarvan vir spesies en plantfunksionele tipes (PFT’s) se reaksie op fragmentasie. Die studie bring verskillende uitwerkings op spesie-oorvloed en PFT’s aan die lig. Wat spesie-oorvloed betref, was die uitwerking van kleiner strookgrootte (“patch size”)duideliker te sien by ASF, waar fragmente kleiner as 600 ha beduidend minder spesies as die moederstrook bevat het. Hierdie uitwerking kon nie so duidelik by SSR en LDS waargeneem word nie weens verskeie strengelingsfaktore, veral die weidingsgeskiedenis van die terreine. Die SSR-fragment waarop inheemse herbivore gewei het, het beduidend meer spesies as die onbeweide terreine bevat. Voorts het die grootste LDS-fragment waarop vee gewei het heelwat meer spesies as die onbeweide moederstrook gehad, wat daarop dui dat weiding eerder as fragmentgrootte spesie-oorvloed beïnvloed, hoewel die kleinste fragmente van hierdie twee plantsoorte steeds aansienlik minder spesies as die groter fragmente bevat het. Spesie-omset en -aanvullendheid was hoog vir ál drie plantsoorte, wat aanwyser is van die mate van habitat-heterogeniteit en die groot bydrae wat betadiversiteit tot algehele gammadiversiteit lewer. Die uitwerking van kleiner strookgrootte was duideliker te bespeur op PFT-diversiteit as PFT-oorvloed – in dié verband het LDS, waar habitatfragmentasie mees onlangs plaasgevind het, die ligste van die drie plantsoorte afgekom. Dít dui op mate van funksionele oorbodigheid in die Kaapse laagland wat belangrik is vir ekosisteemweerstandigheid en -gehardheid. Die ASF-moederstrook en die grootste ASF-fragment het hoër PFT-diversiteit getoon as die medium- en kleinste fragmente; die moederstrook het in werklikheid oor hoër PFT-diversiteit as ál die fragmente saam beskik. Insgelyks het die kleinste SSR-fragment beduidend minder PFT-diversiteit en -oorvloed as die ander terreine getoon. Die beweide SSR-fragment was hoër in PFT-oorvloed én -diversiteit as die onbeweide moederstrook en die kleinste fragment, wat die rol van weiding in die instandhouding van renosterveldplantegroei beklemtoon. Die PFT’s wat nié op die verskillende terreine voorgekom het nie, was meestal tweehuisige en nietweehuisige spesies wat oor kort afstande versprei, en sommige spesies met hoogs gespesialiseerde bestuiwingstelsels. Dít dui daarop dat verspreiding en bestuiwing noodsaaklike funksionele kenmerke vir die voortbestaan van die bestudeerde gefragmenteerde ekosisteme is. Habitatfragmentasie raak die samestelling en ekologiese funksies van plantgemeenskappe in die Kaapse laagland. Dié gevolgtrekking word ook gerugsteun deur die bewese patrone van beduidende kenmerkkonvergensie (“trait convergence”) en divergensiesamekoms (“divergence assembly”). Hierdie plantgemeenskappe spruit uit verskeie fragmentasiefilters wat op verskillende ruimte-tydskale funksioneer, en wat spesies met geskikte reaksies kies. Ál drie plantsoorte is ontvanklik vir fragmentasie, hoewel in wisselende mate. Die fragmentasie-uitwerking is beïnvloed deur monsterinsameling- en tydskale, die soort versteuringsbedeling, en die kenmerkbemiddelde (“traitmediated”) verskille in spesiereaksie. Die rol van die omringende matriks op fragmentverbondenheid en geenvloei blyk van die allergrootste belang te wees, en dus word temperingsmaatreëls aanbeveel wat daarop gemik is om verbondenheid tussen stroke te verbeter, bedreigde taksa te moniteer, en verspreiding en bestuiwing aan te help.