Em ecologia de comunidades buscam-se padrões reproduzíveis, dentre os quais se destaca a busca por regras de montagem ou padrões de organização de comunidades. Diante disso propomos a avaliação desses padrões, com base em convergência e divergência de atributos (TCAP – trait convergence assembly patterns e TDAP – trait divergence assembly patterns, respectivamente), e da influência filogenética na organização de assembléias de espécies lenhosas em florestas. As comunidades foram descritas a partir de atributos funcionais de espécies vegetais, considerando um gradiente sucessional de Floresta Ombrófila Mista, entre áreas que sofreram supressão total da vegetação (denominadas comunidades iniciais) e áreas que não sofreram intervenções expressivas (comunidades avançadas). Para tal, as espécies amostradas, tanto para o estrato superior (indivíduos com DAP ≥ 10 cm), quanto para o estrato inferior (indivíduos com altura > 0,10 m e até 1 cm de DAP), que apresentaram frequência superior a 10%, considerando a amostragem total, foram descritas a partir de 17 atributos funcionais e por relações filogenéticas. Os dados foram analisados a partir de algoritmos baseados em multiplicação e correlações parciais entre diferentes matrizes, que possibilitam discriminar a relevância de TCAP, TDAP e do sinal filogenético para os padrões. Os resultados indicaram que está ocorrendo estruturação das comunidades vegetais a partir dos padrões avaliados, seja convergência ou divergência, relacionados, também, com a filogenia. Diante disso, avaliamos fatores abióticos (filtros ambientais) e bióticos (filtros bióticos) exercem efeitos distintos em comunidades ao longo de um gradiente sucessional, sendo possível observar, também, o sinal filogenético nessas. / In community ecology reproducible patterns are sought, among which stands out the search for assembly rules or assembly patterns. Considering this we propose to evaluate these patterns, based on convergence and divergence of attributes (TCAP – trait convergence assembly patterns and TDAP – trait divergence assembly patterns, respectively) and the phylogenetic influence in the organization of assemblages of woody species in forests. The communities were described from functional traits of plant species, considering a successional gradient of Araucaria Forest, among areas subjected to total removal of vegetation (called initial communities) and areas that haven’t suffered significant interventions (advanced communities). To this end, the species sampled for both the upper stratum (individuals with DBH ≥ 10 cm), and for the lower stratum (individuals with height > 0.10 m and until 1 cm DBH), which had a frequency exceeding 10%, considering the total sampling, were described from 17 functional attributes and phylogenetic relationships. Data were analyzed using algorithms based on multiplication and partial correlations between different matrixes, which permit to discriminate the relevance of TCAP, TDAP and phylogenetic signal to the patterns. The results indicated that is occurring organization of plant communities from the patterns assessed, either convergence or divergence, related also with the phylogeny. Given this, we conclude that abiotic (environmental filters) and biotic (biotic filters) factors exert distinct effects on communities along a successional gradient, and it was possible to observe also the phylogenetic signal in these.

Em ecologia de comunidades buscam-se padrões reproduzíveis, dentre os quais se destaca a busca por regras de montagem ou padrões de organização de comunidades. Diante disso propomos a avaliação desses padrões, com base em convergência e divergência de atributos (TCAP – trait convergence assembly patterns e TDAP – trait divergence assembly patterns, respectivamente), e da influência filogenética na organização de assembléias de espécies lenhosas em florestas. As comunidades foram descritas a partir de atributos funcionais de espécies vegetais, considerando um gradiente sucessional de Floresta Ombrófila Mista, entre áreas que sofreram supressão total da vegetação (denominadas comunidades iniciais) e áreas que não sofreram intervenções expressivas (comunidades avançadas). Para tal, as espécies amostradas, tanto para o estrato superior (indivíduos com DAP ≥ 10 cm), quanto para o estrato inferior (indivíduos com altura > 0,10 m e até 1 cm de DAP), que apresentaram frequência superior a 10%, considerando a amostragem total, foram descritas a partir de 17 atributos funcionais e por relações filogenéticas. Os dados foram analisados a partir de algoritmos baseados em multiplicação e correlações parciais entre diferentes matrizes, que possibilitam discriminar a relevância de TCAP, TDAP e do sinal filogenético para os padrões. Os resultados indicaram que está ocorrendo estruturação das comunidades vegetais a partir dos padrões avaliados, seja convergência ou divergência, relacionados, também, com a filogenia. Diante disso, avaliamos fatores abióticos (filtros ambientais) e bióticos (filtros bióticos) exercem efeitos distintos em comunidades ao longo de um gradiente sucessional, sendo possível observar, também, o sinal filogenético nessas. / In community ecology reproducible patterns are sought, among which stands out the search for assembly rules or assembly patterns. Considering this we propose to evaluate these patterns, based on convergence and divergence of attributes (TCAP – trait convergence assembly patterns and TDAP – trait divergence assembly patterns, respectively) and the phylogenetic influence in the organization of assemblages of woody species in forests. The communities were described from functional traits of plant species, considering a successional gradient of Araucaria Forest, among areas subjected to total removal of vegetation (called initial communities) and areas that haven’t suffered significant interventions (advanced communities). To this end, the species sampled for both the upper stratum (individuals with DBH ≥ 10 cm), and for the lower stratum (individuals with height > 0.10 m and until 1 cm DBH), which had a frequency exceeding 10%, considering the total sampling, were described from 17 functional attributes and phylogenetic relationships. Data were analyzed using algorithms based on multiplication and partial correlations between different matrixes, which permit to discriminate the relevance of TCAP, TDAP and phylogenetic signal to the patterns. The results indicated that is occurring organization of plant communities from the patterns assessed, either convergence or divergence, related also with the phylogeny. Given this, we conclude that abiotic (environmental filters) and biotic (biotic filters) factors exert distinct effects on communities along a successional gradient, and it was possible to observe also the phylogenetic signal in these.

Em ecologia de comunidades buscam-se padrões reproduzíveis, dentre os quais se destaca a busca por regras de montagem ou padrões de organização de comunidades. Diante disso propomos a avaliação desses padrões, com base em convergência e divergência de atributos (TCAP – trait convergence assembly patterns e TDAP – trait divergence assembly patterns, respectivamente), e da influência filogenética na organização de assembléias de espécies lenhosas em florestas. As comunidades foram descritas a partir de atributos funcionais de espécies vegetais, considerando um gradiente sucessional de Floresta Ombrófila Mista, entre áreas que sofreram supressão total da vegetação (denominadas comunidades iniciais) e áreas que não sofreram intervenções expressivas (comunidades avançadas). Para tal, as espécies amostradas, tanto para o estrato superior (indivíduos com DAP ≥ 10 cm), quanto para o estrato inferior (indivíduos com altura > 0,10 m e até 1 cm de DAP), que apresentaram frequência superior a 10%, considerando a amostragem total, foram descritas a partir de 17 atributos funcionais e por relações filogenéticas. Os dados foram analisados a partir de algoritmos baseados em multiplicação e correlações parciais entre diferentes matrizes, que possibilitam discriminar a relevância de TCAP, TDAP e do sinal filogenético para os padrões. Os resultados indicaram que está ocorrendo estruturação das comunidades vegetais a partir dos padrões avaliados, seja convergência ou divergência, relacionados, também, com a filogenia. Diante disso, avaliamos fatores abióticos (filtros ambientais) e bióticos (filtros bióticos) exercem efeitos distintos em comunidades ao longo de um gradiente sucessional, sendo possível observar, também, o sinal filogenético nessas. / In community ecology reproducible patterns are sought, among which stands out the search for assembly rules or assembly patterns. Considering this we propose to evaluate these patterns, based on convergence and divergence of attributes (TCAP – trait convergence assembly patterns and TDAP – trait divergence assembly patterns, respectively) and the phylogenetic influence in the organization of assemblages of woody species in forests. The communities were described from functional traits of plant species, considering a successional gradient of Araucaria Forest, among areas subjected to total removal of vegetation (called initial communities) and areas that haven’t suffered significant interventions (advanced communities). To this end, the species sampled for both the upper stratum (individuals with DBH ≥ 10 cm), and for the lower stratum (individuals with height > 0.10 m and until 1 cm DBH), which had a frequency exceeding 10%, considering the total sampling, were described from 17 functional attributes and phylogenetic relationships. Data were analyzed using algorithms based on multiplication and partial correlations between different matrixes, which permit to discriminate the relevance of TCAP, TDAP and phylogenetic signal to the patterns. The results indicated that is occurring organization of plant communities from the patterns assessed, either convergence or divergence, related also with the phylogeny. Given this, we conclude that abiotic (environmental filters) and biotic (biotic filters) factors exert distinct effects on communities along a successional gradient, and it was possible to observe also the phylogenetic signal in these.

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.

A identificação de atributos funcionais de colêmbolos associada com sua caracterização taxonômica responde aos impactos causados por mudanças de uso e manejo, além de terem um efeito sobre os processos funcionais do solo. Além disso, a descrição de atributos funcionais visa também atender o crescente interesse de investigar mecanismos relacionados com os processos de montagem de comunidade, tais como a convergência e divergência de atributos funcionais. Este trabalho teve três objetivos: 1) investigar a composição e estrutura de comunidades de colêmbolos em relação a alterações de uso do solo e diferentes ofertas de forragem através de uma abordagem funcional e taxonômica; 2) avaliar a existência de filtros ambientais e diferenciação de nichos dentro das comunidades; 3) avaliar o efeito de diferentes grupos funcionais dos colêmbolos no funcionamento do solo. Para isto, foram realizamos três estudos, sendo avaliados no primeiro estudo diferentes usos do solo (mata, campo e eucalipto) e no segundo estudo quatro níveis de ofertas de forragem. Como resultado principal de ambos os estudos, observamos que os de índices taxonômicos, tais como riqueza e diversidade de espécies, podem apresentar padrões diferentes dos índices funcionais, porém ambas as abordagens foram sensíveis aos tratamentos avaliados. De modo geral, o aumento da riqueza e diversidade de colêmbolos não é diretamente relacionado com o aumento da diversidade funcional. Também foi observado em ambos os estudos que a composição e estrutura das comunidades de colêmbolos foram afetadas significativamente pela existência de um filtro ambiental e pela diferenciação de nicho ecológico, uma vez que observamos convergência e divergência de atributos funcionais significativamente relacionados com os gradientes estudados. O terceiro estudo, realizado em condições de microcosmos, consistiram em 6 tratamentos e um controle, sendo os tratamento a combinação de diferentes grupos funcionais de colêmbolos. De modo geral, os resultados mostram que a presença de colêmbolos não afetou significativamente o tamanho da comunidade microbiana do solo, porém estimulou a mineralização de C e N. A presença de apenas um grupo funcional de colêmbolos estimulou a atividade microbiana, sendo estes significativamente diferentes do tratamento controle. Estas diferenças são ainda maiores quando há duas e três grupos funcionais no mesmo microcosmo. O estímulo sobre a comunidade microbiana possivelmente deve-se aos diferentes nichos ocupados pelos colêmbolos dentro do solo, pelas modificações na composição microbiana e pela redistribuição de nutrientes no interior do solo. Palavra-chave: colêmbolos; filtro ambiental; interação biológica; regras de montagem; campos; uso do solo; grupo funcional; atributo funcional; convergência de atributos; divergência de atributos. / Traits-based approach (functional traits) associated with taxonomical description in collembolan communities can response to environmental changes and have a directly effect on soil functioning. Furthermore, trait-based approach also aims to attend the growing interest in investigating mechanisms that are related to assembly process in communities, such as trait-convergence and trait-divergence assembly patterns. This work was three objective: 1) investigating the composition and structure of Collembola communities regarding environmental changes in soil and litter induced by land-use and grassland management using both taxonomic and functional approaches; 2) assessing the existence of environmental filtering and biotic interaction within collembolan communities; 3) evaluating the effect of three collembolan life-form on soil functioning. To this, we carried out three studies to investigate these objectives which two of them was carried out in three land-uses types (study 1) and four herbage allowance (study 2).The results of the studies 1 and 2 showed that taxonomic indices such as richness and taxonomical diversity and functional indices can have different patterns in collembolan communities, but both approaches are sensitive to the treatments evaluated. In general, increasing the richness and diversity of collembola was not directly related with the increase of the functional diversity. We also observed in both studies the composition and structure of Collembolan communities are significantly affected by the existence of an environmental filtering and biotic interaction, since we observed significantly trait-convergence and trait- divergence related to ecological gradients tested. Our findings show that functional traits provide a better understanding of the response of communities to biotic and abiotic changes. The third study was carried out in microcosm conditions and consisted of 6 different combinations of collembolan life-form. Overall, our results showed that collembolan life-forms did not significantly affect microbial biomass but collembolan life-forms affected microbial activities. The presence of only one life-form stimulated C and N mineralization regarding to their CO2 and enzymatic activities, but these stimulations were higher when there was two or three life-forms in the same microcosm. We suggest that stimulation on the microbial community is due to different niches occupied by each collembolan life-form, the changes on microbial composition and redistribution of nutrients in the soil.

Competition between species is believed to lead to patterns of either competitive exclusion or limiting similarity within ecological communities; however, to date the amount of support for either as an outcome has been relatively weak. The two classes of null model commonly used to assess co-occurrence and limiting similarity have both been well studied for statistical performance; however, the methods used to evaluate their performance, particularly in terms of type II statistical errors, may have resulted in the underreporting of both patterns in the communities tested. The overall purpose of this study was to evaluate the efficacy of the negative co-occurrence and limiting similarity null models to detect patterns believed to result from competition between species and to develop an improved method for detecting said patterns. The null models were tested using synthetic but biologically realistic presence-absence matrices for both type I and type II error rate estimations. The effectiveness of the null models was evaluated with respect to community dimension (number of species × number of plots), and amount of pattern within the community. A novel method of subsetting species was developed to assess communities for patterns of co-occurrence and limiting similarity and four methods were assessed for their ability to isolate the species contributing signal to the pattern. Both classes of null model provided acceptable type I and type II error rates when matrices of more than 5 species and more than 5 plots were tested. When patterns of negative co-occurrence or limiting similarity were add to all species both null models were able to detect significant pattern (β > 0.95); however, when pattern was added to only a proportion of species the ability of the null models to detect pattern deteriorated rapidly with proportions of 80% or less. The use of species subsetting was able to detect significant pattern of both co-occurrence and limiting similarity when fewer than 80% of species were contributing signal but was dependent on the metric used for the limiting similarity null model. The ability of frequent pattern mining to isolate the species contributing signal shows promise; however, a more thorough evaluation is required in order to confirm or deny its utility.

A identificação de atributos funcionais de colêmbolos associada com sua caracterização taxonômica responde aos impactos causados por mudanças de uso e manejo, além de terem um efeito sobre os processos funcionais do solo. Além disso, a descrição de atributos funcionais visa também atender o crescente interesse de investigar mecanismos relacionados com os processos de montagem de comunidade, tais como a convergência e divergência de atributos funcionais. Este trabalho teve três objetivos: 1) investigar a composição e estrutura de comunidades de colêmbolos em relação a alterações de uso do solo e diferentes ofertas de forragem através de uma abordagem funcional e taxonômica; 2) avaliar a existência de filtros ambientais e diferenciação de nichos dentro das comunidades; 3) avaliar o efeito de diferentes grupos funcionais dos colêmbolos no funcionamento do solo. Para isto, foram realizamos três estudos, sendo avaliados no primeiro estudo diferentes usos do solo (mata, campo e eucalipto) e no segundo estudo quatro níveis de ofertas de forragem. Como resultado principal de ambos os estudos, observamos que os de índices taxonômicos, tais como riqueza e diversidade de espécies, podem apresentar padrões diferentes dos índices funcionais, porém ambas as abordagens foram sensíveis aos tratamentos avaliados. De modo geral, o aumento da riqueza e diversidade de colêmbolos não é diretamente relacionado com o aumento da diversidade funcional. Também foi observado em ambos os estudos que a composição e estrutura das comunidades de colêmbolos foram afetadas significativamente pela existência de um filtro ambiental e pela diferenciação de nicho ecológico, uma vez que observamos convergência e divergência de atributos funcionais significativamente relacionados com os gradientes estudados. O terceiro estudo, realizado em condições de microcosmos, consistiram em 6 tratamentos e um controle, sendo os tratamento a combinação de diferentes grupos funcionais de colêmbolos. De modo geral, os resultados mostram que a presença de colêmbolos não afetou significativamente o tamanho da comunidade microbiana do solo, porém estimulou a mineralização de C e N. A presença de apenas um grupo funcional de colêmbolos estimulou a atividade microbiana, sendo estes significativamente diferentes do tratamento controle. Estas diferenças são ainda maiores quando há duas e três grupos funcionais no mesmo microcosmo. O estímulo sobre a comunidade microbiana possivelmente deve-se aos diferentes nichos ocupados pelos colêmbolos dentro do solo, pelas modificações na composição microbiana e pela redistribuição de nutrientes no interior do solo. Palavra-chave: colêmbolos; filtro ambiental; interação biológica; regras de montagem; campos; uso do solo; grupo funcional; atributo funcional; convergência de atributos; divergência de atributos. / Traits-based approach (functional traits) associated with taxonomical description in collembolan communities can response to environmental changes and have a directly effect on soil functioning. Furthermore, trait-based approach also aims to attend the growing interest in investigating mechanisms that are related to assembly process in communities, such as trait-convergence and trait-divergence assembly patterns. This work was three objective: 1) investigating the composition and structure of Collembola communities regarding environmental changes in soil and litter induced by land-use and grassland management using both taxonomic and functional approaches; 2) assessing the existence of environmental filtering and biotic interaction within collembolan communities; 3) evaluating the effect of three collembolan life-form on soil functioning. To this, we carried out three studies to investigate these objectives which two of them was carried out in three land-uses types (study 1) and four herbage allowance (study 2).The results of the studies 1 and 2 showed that taxonomic indices such as richness and taxonomical diversity and functional indices can have different patterns in collembolan communities, but both approaches are sensitive to the treatments evaluated. In general, increasing the richness and diversity of collembola was not directly related with the increase of the functional diversity. We also observed in both studies the composition and structure of Collembolan communities are significantly affected by the existence of an environmental filtering and biotic interaction, since we observed significantly trait-convergence and trait- divergence related to ecological gradients tested. Our findings show that functional traits provide a better understanding of the response of communities to biotic and abiotic changes. The third study was carried out in microcosm conditions and consisted of 6 different combinations of collembolan life-form. Overall, our results showed that collembolan life-forms did not significantly affect microbial biomass but collembolan life-forms affected microbial activities. The presence of only one life-form stimulated C and N mineralization regarding to their CO2 and enzymatic activities, but these stimulations were higher when there was two or three life-forms in the same microcosm. We suggest that stimulation on the microbial community is due to different niches occupied by each collembolan life-form, the changes on microbial composition and redistribution of nutrients in the soil.

A identificação de atributos funcionais de colêmbolos associada com sua caracterização taxonômica responde aos impactos causados por mudanças de uso e manejo, além de terem um efeito sobre os processos funcionais do solo. Além disso, a descrição de atributos funcionais visa também atender o crescente interesse de investigar mecanismos relacionados com os processos de montagem de comunidade, tais como a convergência e divergência de atributos funcionais. Este trabalho teve três objetivos: 1) investigar a composição e estrutura de comunidades de colêmbolos em relação a alterações de uso do solo e diferentes ofertas de forragem através de uma abordagem funcional e taxonômica; 2) avaliar a existência de filtros ambientais e diferenciação de nichos dentro das comunidades; 3) avaliar o efeito de diferentes grupos funcionais dos colêmbolos no funcionamento do solo. Para isto, foram realizamos três estudos, sendo avaliados no primeiro estudo diferentes usos do solo (mata, campo e eucalipto) e no segundo estudo quatro níveis de ofertas de forragem. Como resultado principal de ambos os estudos, observamos que os de índices taxonômicos, tais como riqueza e diversidade de espécies, podem apresentar padrões diferentes dos índices funcionais, porém ambas as abordagens foram sensíveis aos tratamentos avaliados. De modo geral, o aumento da riqueza e diversidade de colêmbolos não é diretamente relacionado com o aumento da diversidade funcional. Também foi observado em ambos os estudos que a composição e estrutura das comunidades de colêmbolos foram afetadas significativamente pela existência de um filtro ambiental e pela diferenciação de nicho ecológico, uma vez que observamos convergência e divergência de atributos funcionais significativamente relacionados com os gradientes estudados. O terceiro estudo, realizado em condições de microcosmos, consistiram em 6 tratamentos e um controle, sendo os tratamento a combinação de diferentes grupos funcionais de colêmbolos. De modo geral, os resultados mostram que a presença de colêmbolos não afetou significativamente o tamanho da comunidade microbiana do solo, porém estimulou a mineralização de C e N. A presença de apenas um grupo funcional de colêmbolos estimulou a atividade microbiana, sendo estes significativamente diferentes do tratamento controle. Estas diferenças são ainda maiores quando há duas e três grupos funcionais no mesmo microcosmo. O estímulo sobre a comunidade microbiana possivelmente deve-se aos diferentes nichos ocupados pelos colêmbolos dentro do solo, pelas modificações na composição microbiana e pela redistribuição de nutrientes no interior do solo. Palavra-chave: colêmbolos; filtro ambiental; interação biológica; regras de montagem; campos; uso do solo; grupo funcional; atributo funcional; convergência de atributos; divergência de atributos. / Traits-based approach (functional traits) associated with taxonomical description in collembolan communities can response to environmental changes and have a directly effect on soil functioning. Furthermore, trait-based approach also aims to attend the growing interest in investigating mechanisms that are related to assembly process in communities, such as trait-convergence and trait-divergence assembly patterns. This work was three objective: 1) investigating the composition and structure of Collembola communities regarding environmental changes in soil and litter induced by land-use and grassland management using both taxonomic and functional approaches; 2) assessing the existence of environmental filtering and biotic interaction within collembolan communities; 3) evaluating the effect of three collembolan life-form on soil functioning. To this, we carried out three studies to investigate these objectives which two of them was carried out in three land-uses types (study 1) and four herbage allowance (study 2).The results of the studies 1 and 2 showed that taxonomic indices such as richness and taxonomical diversity and functional indices can have different patterns in collembolan communities, but both approaches are sensitive to the treatments evaluated. In general, increasing the richness and diversity of collembola was not directly related with the increase of the functional diversity. We also observed in both studies the composition and structure of Collembolan communities are significantly affected by the existence of an environmental filtering and biotic interaction, since we observed significantly trait-convergence and trait- divergence related to ecological gradients tested. Our findings show that functional traits provide a better understanding of the response of communities to biotic and abiotic changes. The third study was carried out in microcosm conditions and consisted of 6 different combinations of collembolan life-form. Overall, our results showed that collembolan life-forms did not significantly affect microbial biomass but collembolan life-forms affected microbial activities. The presence of only one life-form stimulated C and N mineralization regarding to their CO2 and enzymatic activities, but these stimulations were higher when there was two or three life-forms in the same microcosm. We suggest that stimulation on the microbial community is due to different niches occupied by each collembolan life-form, the changes on microbial composition and redistribution of nutrients in the soil.