São poucos os estudos da flora no Núcleo Cabuçu, mais raro ainda é o estudo das plantas herbáceas. Este estudo teve como objetivo geral conhecer a composição florística e estrutural de uma área localizada na região de borda do Núcleo Cabuçu, Parque Estadual da Cantareira, município de Guarulhos/SP. Para tanto, foram amostradas três áreas, com fisionomia e estádios distintos de sucessão, denominadas de capoeira, mata e pinus, em cinco transecções paralelas distanciadas em 20m. Nestas transecções foram marcadas as parcelas de 4m2 (2m X 2m) a cada 10m, compondo 38 amostras. Foram realizados o levantamento, a localização, a identificação das espécies vegetais arbóreas, herbáceas, oportunistas de clareiras, nativas e exóticas com DAP (diâmetro na altura do peito) menor que 10 cm, a análise da estrutura horizontal, a variação interna da composição, a riqueza e a diversidade da área, o reconhecimento das espécies características das séries sucessionais e a verificação das possíveis espécies indicadoras destes estádios. Foi também estudada a dinâmica da paisagem enfocando níveis pontuais, através de zoneamento em unidades, estratificando os diferentes tipos de vegetação e níveis sucessionais através da integração dos procedimentos geoestatísticos em SIG (sistema de informação geográfica), visando contribuir com estas informações para a conservação e adoção de práticas corretas para a proteção das florestas atlânticas e da reserva da biosfera do Cinturão Verde da cidade de São Paulo. Foram levantados 3405 espécimes nas amostras, distribuídos em 123 espécies, pertencentes a 95 gêneros e 41 famílias, incluindo quatro morfo-espécies identificadas até família e 25 morfo-espécies identificadas até gênero. A análise revelou grande divergência na composição florística relativa à riqueza e diversidade, além das diferenças estruturais (abundância e freqüência) nas diferentes tipologias. É de considerável relevância a elevada diversidade de espécies encontradas na região em estudo, comprovada pelo índice de \"Shannon\" (3,18 nits/ind). Com relação a este índice, a diversidade da área de mata (3,45 nits/ind) possui elevado valor comparando-se com áreas de florestas tropicais. As áreas de pinus (2,57 nits/ind) e capoeira (2,02 nits/ind) apresentaram valores próximos. As áreas de pinus e capoeira divergiram em riqueza, sendo esta maior na área de pinus. Já na área de mata a riqueza foi superior devido à presença de espécies raras. Foram encontradas espécies exóticas, porém não com características de invasoras. / There are few studies on the flora of Núcleo Cabuçu, and fewer still are the studies on herbaceous plants. The aim of this study was to acknowledge the floristical and structural composition of an area located in the edge of Núcleo Cabuçu, Parque Estadual da Cantareira, municipallity of Guarulhos/SP. Three areas with distinct phisiognomy and successional stages, called capoeira, mata and pinus, were sampled in five parallel transections distant 20m from each other. In these transections, 4m2 (2m X 2m) plots were established every 10m, totaling 38 samples. The survey, location, and identification of arboreal, herbaceous, gap opportunistic, native and exotic plants with DBH (diameter at breast height) lower than 10cm, were conducted, as well as the analysis of the horizontal structure, internal variation composition, richness and diversity of the areas, the recognition of species characteristic of successional series and the verification of possible indicator species of these stages. The landscape dynamics was also studied, with emphasis at punctual levels, through unit zoning, stratifying the different types of vegetation and successional levels through the integration of geostatistics methods such as GIS (geographic information system), aiming with this knowledge to contribute for the conservation and adoption of adequate practices for the protection of the Atlantic forests and the biosphere reserve of the Green Belt of Sao Paulo city. A total of 3405 specimens were sampled, distributed among 123 species, belonging to 95 genera and 41 botanical families, including four morpho-species identified up to the family level and 25 morpho-species identified up to the genus level. The analyses revealed high divergence in the floristical composition relative to the richness and diversity, besides structural differences (abundance and frequency) in the different typologies. Of a strong relevance is the high species diversity found in the study area, confirmed with the \"Shannon\" index (3.18 nits/ind). The diversity in the mata area (3.45 nits/ind) was high when compared to other areas of tropical forests. The areas of pinus (2.57 nits/ind) and capoeira (2.02 nits/ind) presented similar values. These two areas were divergent in richness, which was higher in the pinus area. In the area of mata the richness was superior due to the presence of rare species. Exotic species were found in the study area, but with no invasive characteristics.

Herbaceous communities are critical to the functioning of forest ecosystems. They recycle nutrients, help prevent erosion, provide critical microhabitats and maintain biodiversity. In the eastern United States, most hardwood forests are growing on land once entirely cleared or used for some form of agriculture. Although some of these forests are nearly 150 years old, they still have depauperate native herbaceous communities when compared to remaining old-growth forests. This long-term depletion may result from dispersal limitation or environmental limitation. I tested the hypothesis that dispersal was the primary factor contributing to the absence of five spring-flowering herbaceous species in four secondary mesic hardwood forests. I transplanted adults and sowed fresh propagules into chosen forests. By establishing negative controls, I showed that propagules of experimental species were not incidentally dispersed and would not have been present at the sites had I not introduced them. In all four sites, seeds of three ant-dispersed species germinated and adults of these species survived, flowered and self-sowed viable propagules. These results strongly indicated dispersal limitation in all sites. Another ant-dispersed species showed evidence of being dispersal-limited in at least two sites. The limitations of one gravity-dispersed species were unclear. I discuss results from the first year after transplanting and offer management suggestions to facilitate the return of these species to degraded forests.

O objetivo geral desta tese foi caracterizar a diversidade, estrutura e dinâmica da vegetação e verificar a chuva de sementes ornitocóricas em comunidades secundárias de Floresta Atlântica de Terras Baixas no sul do Brasil. As áreas de estudo localizam-se no município de Dom Pedro de Alcântara (29°22'59"S 49°50'18"W), Rio Grande do Sul. Constituem comunidades secundárias com aproximadamente cinco (5a.) e vinte anos (20a.) de abandono após uso como pastagem e cultivos, respectivamente. As áreas são adjacentes a um remanescente pouco alterado de floresta primária. Foi feito o levantamento florístico e fitossociológico do componente herbáceo-subarbustivo e da sinúsia arbórea. Para as árvores foram consideradas plântulas (20 cm < altura < 100 cm), juvenis (altura >= 100 cm, DAP < 5 cm) e adultas (DAP >= 5 cm). A classe adulta foi reamostrada após dois anos do levantamento inicial. Também foi verificada a chuva de sementes mediada por aves sob poleiros artificiais instalados na capoeira 5a. durante dois anos. As duas áreas tiveram diferenças significativas. O componente herbáceo-arbustivo apresentou 76 espécies, das quais 77% heliófilas, e 2,305 nats/ind na capoeira 5a. e 34 espécies, 44% heliófilas e 1,961 nats/ind na capoeira 20a. O componente regenerante da sinúsia arbórea teve maior densidade e diversidade do que a classe adulta nas duas áreas. A similaridade florística foi maior entre a classe das plântulas e juvenis. A classe adulta da capoeira 5a. apresentou elevado recrutamento (186%) e baixa mortalidade (14%), com maior cobertura, riqueza e diversidade no segundo levantamento. A composição e estrutura da classe das árvores adultas não tiveram mudanças significativas na capoeira 20a. A chuva de sementes ornitocóricas foi significativamente aumentada pelo uso dos poleiros, com 8.878 sementes/ano, especialmente de Ficus spp., Trema micrantha e Cecropia spp. A chuva de sementes foi mais abundante no verão (47%) e no outono (32%). A densidade e riqueza de sementes mostraram-se positivamente associadas às médias mensais de temperatura, com maior densidade em coletores distantes de bordas florestais. O tipo de uso pretérito, a fertilidade do solo, o sombreamento nos estratos inferiores e a distância de bordas florestais influenciam a composição florística, a estrutura e a dinâmica dessas comunidades secundárias. Além disso, a chuva de sementes ornitocóricas foi abundante e composta basicamente por espécies pioneiras, variando com a oferta de frutos e a dispersão feita por aves que forrageiam em áreas abertas e bordas florestais. / The general purpose of this thesis was to describe vegetation diversity, structure and dynamics and to verify bird mediated seed rain in secondary communities of Lowland Atlantic Rain Forest in southern Brazil. Studied areas are located in Dom Pedro de Alcântara municipality (29°22'59"S 49°50'18"W), Rio Grande do Sul. These areas constitute secondary communities with five (5y.) and 20 years (20y.) of abandonment after use as pasture and plantations, respectively. Bordering the areas, there's a slightly altered remnant of primary forest. Floristic and phytosociological survey of herbaceous-subshrubby component and tree synusiae was performed. Survey of tree synusiae considered seedlings (20 cm < height < 100 cm), saplings (height >= 100 cm, DBH < 5 cm) and adults (DBH >= 5 cm). After two years from initial survey, adult trees were resampled. During two years, bird mediated seed rain under artificial perches installed in 'capoeira' 5y. was verified. Both areas had significant differences. Herbaceous-subshrubby component had 76 species, of which 77% light-demanding, and 2.305 nats/ind. in 'capoeira' 5y., and 34 species, 44% light-demanding and 1.961 nats/ind. in 'capoeira' 5y. Regenerating component of the tree synusiae had higher density and diversity than the adult class in both areas. Floristic similarity was superior between seedlings and saplings. Adult class of 'capoeira' 5y. had elevated recruitment (186%) and low mortality (14%), with higher basal cover, richness and diversity in the second survey. Composition and structure of adult class didn't have significant changes in 'capoeira' 20y. Ornithochoric seed rain was significantly increased by perch use, with 8,878 seeds/year, specially of Ficus spp., Trema micrantha and Cecropia spp. Seed rain was more abundant in the summer (47%) and fall (32%). Seed density and richness were positively associated to monthly atmospheric temperatures, with higher density in traps far away from forest edges. Past land use, soil fertility, inferior strata shading, and distance from forest edges influenced floristic composition, structure and dynamics of these secondary communities. Moreover, ornithochoric seed rain was abundant and composed mainly by pioneer species, varying with fruit offer and dispersal promoted by birds that forrage in open areas and forest edges.

O objetivo geral desta tese foi caracterizar a diversidade, estrutura e dinâmica da vegetação e verificar a chuva de sementes ornitocóricas em comunidades secundárias de Floresta Atlântica de Terras Baixas no sul do Brasil. As áreas de estudo localizam-se no município de Dom Pedro de Alcântara (29°22'59"S 49°50'18"W), Rio Grande do Sul. Constituem comunidades secundárias com aproximadamente cinco (5a.) e vinte anos (20a.) de abandono após uso como pastagem e cultivos, respectivamente. As áreas são adjacentes a um remanescente pouco alterado de floresta primária. Foi feito o levantamento florístico e fitossociológico do componente herbáceo-subarbustivo e da sinúsia arbórea. Para as árvores foram consideradas plântulas (20 cm < altura < 100 cm), juvenis (altura >= 100 cm, DAP < 5 cm) e adultas (DAP >= 5 cm). A classe adulta foi reamostrada após dois anos do levantamento inicial. Também foi verificada a chuva de sementes mediada por aves sob poleiros artificiais instalados na capoeira 5a. durante dois anos. As duas áreas tiveram diferenças significativas. O componente herbáceo-arbustivo apresentou 76 espécies, das quais 77% heliófilas, e 2,305 nats/ind na capoeira 5a. e 34 espécies, 44% heliófilas e 1,961 nats/ind na capoeira 20a. O componente regenerante da sinúsia arbórea teve maior densidade e diversidade do que a classe adulta nas duas áreas. A similaridade florística foi maior entre a classe das plântulas e juvenis. A classe adulta da capoeira 5a. apresentou elevado recrutamento (186%) e baixa mortalidade (14%), com maior cobertura, riqueza e diversidade no segundo levantamento. A composição e estrutura da classe das árvores adultas não tiveram mudanças significativas na capoeira 20a. A chuva de sementes ornitocóricas foi significativamente aumentada pelo uso dos poleiros, com 8.878 sementes/ano, especialmente de Ficus spp., Trema micrantha e Cecropia spp. A chuva de sementes foi mais abundante no verão (47%) e no outono (32%). A densidade e riqueza de sementes mostraram-se positivamente associadas às médias mensais de temperatura, com maior densidade em coletores distantes de bordas florestais. O tipo de uso pretérito, a fertilidade do solo, o sombreamento nos estratos inferiores e a distância de bordas florestais influenciam a composição florística, a estrutura e a dinâmica dessas comunidades secundárias. Além disso, a chuva de sementes ornitocóricas foi abundante e composta basicamente por espécies pioneiras, variando com a oferta de frutos e a dispersão feita por aves que forrageiam em áreas abertas e bordas florestais. / The general purpose of this thesis was to describe vegetation diversity, structure and dynamics and to verify bird mediated seed rain in secondary communities of Lowland Atlantic Rain Forest in southern Brazil. Studied areas are located in Dom Pedro de Alcântara municipality (29°22'59"S 49°50'18"W), Rio Grande do Sul. These areas constitute secondary communities with five (5y.) and 20 years (20y.) of abandonment after use as pasture and plantations, respectively. Bordering the areas, there's a slightly altered remnant of primary forest. Floristic and phytosociological survey of herbaceous-subshrubby component and tree synusiae was performed. Survey of tree synusiae considered seedlings (20 cm < height < 100 cm), saplings (height >= 100 cm, DBH < 5 cm) and adults (DBH >= 5 cm). After two years from initial survey, adult trees were resampled. During two years, bird mediated seed rain under artificial perches installed in 'capoeira' 5y. was verified. Both areas had significant differences. Herbaceous-subshrubby component had 76 species, of which 77% light-demanding, and 2.305 nats/ind. in 'capoeira' 5y., and 34 species, 44% light-demanding and 1.961 nats/ind. in 'capoeira' 5y. Regenerating component of the tree synusiae had higher density and diversity than the adult class in both areas. Floristic similarity was superior between seedlings and saplings. Adult class of 'capoeira' 5y. had elevated recruitment (186%) and low mortality (14%), with higher basal cover, richness and diversity in the second survey. Composition and structure of adult class didn't have significant changes in 'capoeira' 20y. Ornithochoric seed rain was significantly increased by perch use, with 8,878 seeds/year, specially of Ficus spp., Trema micrantha and Cecropia spp. Seed rain was more abundant in the summer (47%) and fall (32%). Seed density and richness were positively associated to monthly atmospheric temperatures, with higher density in traps far away from forest edges. Past land use, soil fertility, inferior strata shading, and distance from forest edges influenced floristic composition, structure and dynamics of these secondary communities. Moreover, ornithochoric seed rain was abundant and composed mainly by pioneer species, varying with fruit offer and dispersal promoted by birds that forrage in open areas and forest edges.

Mountain forests are an important part of the landscape in our country. In the last three decades they have been seriously damaged by anthropogenic influence, especially immissions. The immissions make worse the health status of Norway spruce (Picea abies) forests, which cause changes in a structure of herbaceous layer, in which the health status of forest stand is reflected. The main goals of my work were to map the cover of herbaceous and mossy layers in two permanent research plots in the Giant Mountains ( Alžbětinka, Modrý důl), to create maps of herbaceous cover, to digitize them and to compare these maps with the extent in years 1993-1994 using a developing analysis in GIS and to detect influence of light conditions on herbaceous layer. Using digitizing and static evaluation of prepared detailed vegetation maps of the both permanent research plots, some important changes were found out in dominant soil cover categories. In the first research plot Alžbětinka, decline of the grass Calamagrostis villosa and increasing of Vaccinium myrtillus cover were evident. In the second research plot Modrý důl, decline of both investigated species, Avenella flexuosa and Calamagrostis villosa, was observed. Another goal of my research was to detect influence of the light conditions on herbaceous layer and nature regeneration of the Norway spruce on permanent research plot Modrý důl. Dependence of the basic categories of the soil cover on the percentual ratio of the light gaps in the crown canopy was proved. Dependence of the height of the seedlings on the ratio of the light gaps was also tested but it was not statistically proved. The negative dependence of survival on the ratio of the light gaps of the seedlings germinated in 1996 was proved, but not of the seedlings germinated in 2004.

The aim of this study was to summarize information about the behavior of mercury in soils, particularly the assessment of its mobility and bioavailability, and to verify the extent of contamination of alluvial soils under the reservoir Skalka. This research was aimed to evaluate the contamination of mercury floodplain soils with mercury belong the upper river Ohře near the town of Chvoječná, near 230th river kilometer. River sediments of the upper river Ohře and the surrounding alluvial soils in floodplains contain high mercury levels. The site has been sampled for mercury analysis of soil samples taken from farmed areas, which are expected enrichment of mercury deposits of the inserted river Ohře. There were two main types of land-use, permanent grassland and arable land. The observed results can be concluded that the river floodplain sediments enrich the soil with mercury. Analytical method (atomic absorption spectrometry, CV-AAS) showed that almost all surface soil samples from the flooded area exceeds the maximum allowed value (for light soils 0.6 mg.kg-1 and other land 0.8 mg.kg-1 ) that are designated for agricultural land. Indicative of mercury was determined by mobility, which was up to 2.18%. Levels of organic forms of mercury were also measured in the soils that reached the area of grassland 2 maximum 0.147 mg.kg-1; the subsidiary surface S1 had the relative distribution of organic mercury 10.98% at a depth of 101-140 cm.

São poucos os estudos da flora no Núcleo Cabuçu, mais raro ainda é o estudo das plantas herbáceas. Este estudo teve como objetivo geral conhecer a composição florística e estrutural de uma área localizada na região de borda do Núcleo Cabuçu, Parque Estadual da Cantareira, município de Guarulhos/SP. Para tanto, foram amostradas três áreas, com fisionomia e estádios distintos de sucessão, denominadas de capoeira, mata e pinus, em cinco transecções paralelas distanciadas em 20m. Nestas transecções foram marcadas as parcelas de 4m2 (2m X 2m) a cada 10m, compondo 38 amostras. Foram realizados o levantamento, a localização, a identificação das espécies vegetais arbóreas, herbáceas, oportunistas de clareiras, nativas e exóticas com DAP (diâmetro na altura do peito) menor que 10 cm, a análise da estrutura horizontal, a variação interna da composição, a riqueza e a diversidade da área, o reconhecimento das espécies características das séries sucessionais e a verificação das possíveis espécies indicadoras destes estádios. Foi também estudada a dinâmica da paisagem enfocando níveis pontuais, através de zoneamento em unidades, estratificando os diferentes tipos de vegetação e níveis sucessionais através da integração dos procedimentos geoestatísticos em SIG (sistema de informação geográfica), visando contribuir com estas informações para a conservação e adoção de práticas corretas para a proteção das florestas atlânticas e da reserva da biosfera do Cinturão Verde da cidade de São Paulo. Foram levantados 3405 espécimes nas amostras, distribuídos em 123 espécies, pertencentes a 95 gêneros e 41 famílias, incluindo quatro morfo-espécies identificadas até família e 25 morfo-espécies identificadas até gênero. A análise revelou grande divergência na composição florística relativa à riqueza e diversidade, além das diferenças estruturais (abundância e freqüência) nas diferentes tipologias. É de considerável relevância a elevada diversidade de espécies encontradas na região em estudo, comprovada pelo índice de \"Shannon\" (3,18 nits/ind). Com relação a este índice, a diversidade da área de mata (3,45 nits/ind) possui elevado valor comparando-se com áreas de florestas tropicais. As áreas de pinus (2,57 nits/ind) e capoeira (2,02 nits/ind) apresentaram valores próximos. As áreas de pinus e capoeira divergiram em riqueza, sendo esta maior na área de pinus. Já na área de mata a riqueza foi superior devido à presença de espécies raras. Foram encontradas espécies exóticas, porém não com características de invasoras. / There are few studies on the flora of Núcleo Cabuçu, and fewer still are the studies on herbaceous plants. The aim of this study was to acknowledge the floristical and structural composition of an area located in the edge of Núcleo Cabuçu, Parque Estadual da Cantareira, municipallity of Guarulhos/SP. Three areas with distinct phisiognomy and successional stages, called capoeira, mata and pinus, were sampled in five parallel transections distant 20m from each other. In these transections, 4m2 (2m X 2m) plots were established every 10m, totaling 38 samples. The survey, location, and identification of arboreal, herbaceous, gap opportunistic, native and exotic plants with DBH (diameter at breast height) lower than 10cm, were conducted, as well as the analysis of the horizontal structure, internal variation composition, richness and diversity of the areas, the recognition of species characteristic of successional series and the verification of possible indicator species of these stages. The landscape dynamics was also studied, with emphasis at punctual levels, through unit zoning, stratifying the different types of vegetation and successional levels through the integration of geostatistics methods such as GIS (geographic information system), aiming with this knowledge to contribute for the conservation and adoption of adequate practices for the protection of the Atlantic forests and the biosphere reserve of the Green Belt of Sao Paulo city. A total of 3405 specimens were sampled, distributed among 123 species, belonging to 95 genera and 41 botanical families, including four morpho-species identified up to the family level and 25 morpho-species identified up to the genus level. The analyses revealed high divergence in the floristical composition relative to the richness and diversity, besides structural differences (abundance and frequency) in the different typologies. Of a strong relevance is the high species diversity found in the study area, confirmed with the \"Shannon\" index (3.18 nits/ind). The diversity in the mata area (3.45 nits/ind) was high when compared to other areas of tropical forests. The areas of pinus (2.57 nits/ind) and capoeira (2.02 nits/ind) presented similar values. These two areas were divergent in richness, which was higher in the pinus area. In the area of mata the richness was superior due to the presence of rare species. Exotic species were found in the study area, but with no invasive characteristics.

O objetivo geral desta tese foi caracterizar a diversidade, estrutura e dinâmica da vegetação e verificar a chuva de sementes ornitocóricas em comunidades secundárias de Floresta Atlântica de Terras Baixas no sul do Brasil. As áreas de estudo localizam-se no município de Dom Pedro de Alcântara (29°22'59"S 49°50'18"W), Rio Grande do Sul. Constituem comunidades secundárias com aproximadamente cinco (5a.) e vinte anos (20a.) de abandono após uso como pastagem e cultivos, respectivamente. As áreas são adjacentes a um remanescente pouco alterado de floresta primária. Foi feito o levantamento florístico e fitossociológico do componente herbáceo-subarbustivo e da sinúsia arbórea. Para as árvores foram consideradas plântulas (20 cm < altura < 100 cm), juvenis (altura >= 100 cm, DAP < 5 cm) e adultas (DAP >= 5 cm). A classe adulta foi reamostrada após dois anos do levantamento inicial. Também foi verificada a chuva de sementes mediada por aves sob poleiros artificiais instalados na capoeira 5a. durante dois anos. As duas áreas tiveram diferenças significativas. O componente herbáceo-arbustivo apresentou 76 espécies, das quais 77% heliófilas, e 2,305 nats/ind na capoeira 5a. e 34 espécies, 44% heliófilas e 1,961 nats/ind na capoeira 20a. O componente regenerante da sinúsia arbórea teve maior densidade e diversidade do que a classe adulta nas duas áreas. A similaridade florística foi maior entre a classe das plântulas e juvenis. A classe adulta da capoeira 5a. apresentou elevado recrutamento (186%) e baixa mortalidade (14%), com maior cobertura, riqueza e diversidade no segundo levantamento. A composição e estrutura da classe das árvores adultas não tiveram mudanças significativas na capoeira 20a. A chuva de sementes ornitocóricas foi significativamente aumentada pelo uso dos poleiros, com 8.878 sementes/ano, especialmente de Ficus spp., Trema micrantha e Cecropia spp. A chuva de sementes foi mais abundante no verão (47%) e no outono (32%). A densidade e riqueza de sementes mostraram-se positivamente associadas às médias mensais de temperatura, com maior densidade em coletores distantes de bordas florestais. O tipo de uso pretérito, a fertilidade do solo, o sombreamento nos estratos inferiores e a distância de bordas florestais influenciam a composição florística, a estrutura e a dinâmica dessas comunidades secundárias. Além disso, a chuva de sementes ornitocóricas foi abundante e composta basicamente por espécies pioneiras, variando com a oferta de frutos e a dispersão feita por aves que forrageiam em áreas abertas e bordas florestais. / The general purpose of this thesis was to describe vegetation diversity, structure and dynamics and to verify bird mediated seed rain in secondary communities of Lowland Atlantic Rain Forest in southern Brazil. Studied areas are located in Dom Pedro de Alcântara municipality (29°22'59"S 49°50'18"W), Rio Grande do Sul. These areas constitute secondary communities with five (5y.) and 20 years (20y.) of abandonment after use as pasture and plantations, respectively. Bordering the areas, there's a slightly altered remnant of primary forest. Floristic and phytosociological survey of herbaceous-subshrubby component and tree synusiae was performed. Survey of tree synusiae considered seedlings (20 cm < height < 100 cm), saplings (height >= 100 cm, DBH < 5 cm) and adults (DBH >= 5 cm). After two years from initial survey, adult trees were resampled. During two years, bird mediated seed rain under artificial perches installed in 'capoeira' 5y. was verified. Both areas had significant differences. Herbaceous-subshrubby component had 76 species, of which 77% light-demanding, and 2.305 nats/ind. in 'capoeira' 5y., and 34 species, 44% light-demanding and 1.961 nats/ind. in 'capoeira' 5y. Regenerating component of the tree synusiae had higher density and diversity than the adult class in both areas. Floristic similarity was superior between seedlings and saplings. Adult class of 'capoeira' 5y. had elevated recruitment (186%) and low mortality (14%), with higher basal cover, richness and diversity in the second survey. Composition and structure of adult class didn't have significant changes in 'capoeira' 20y. Ornithochoric seed rain was significantly increased by perch use, with 8,878 seeds/year, specially of Ficus spp., Trema micrantha and Cecropia spp. Seed rain was more abundant in the summer (47%) and fall (32%). Seed density and richness were positively associated to monthly atmospheric temperatures, with higher density in traps far away from forest edges. Past land use, soil fertility, inferior strata shading, and distance from forest edges influenced floristic composition, structure and dynamics of these secondary communities. Moreover, ornithochoric seed rain was abundant and composed mainly by pioneer species, varying with fruit offer and dispersal promoted by birds that forrage in open areas and forest edges.

Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2017-02-21T14:40:07Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertação Lígia Gomes Ferreira de Souza.pdf: 862040 bytes, checksum: 84b33fa4d8721af1d396e97801bddc15 (MD5) / Made available in DSpace on 2017-02-21T14:40:07Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertação Lígia Gomes Ferreira de Souza.pdf: 862040 bytes, checksum: 84b33fa4d8721af1d396e97801bddc15 (MD5) Previous issue date: 2016-02-25 / CNPq / A presença de rios sempre foi uma das condições primárias para o estabelecimento de grupos humanos, e as atividades destes grupos têm causado grande empobrecimento ambiental. Na caatinga, onde as características meteorológicas são consideradas extremas e o regime de chuvas é bastante irregular, a vegetação às margens dos rios encontra-se numa situação de perda de biodiversidade. Sendo assim, este estudo teve por objetivo gerar informações que contribuam em futuros projetos de recuperação de matas ciliares em regiões semiáridas através da avaliação do banco de sementes do solo de três localidades (Preservada, Intermediária e Degradada) submetidas a diferentes usos da terra em uma região de caatinga. Quarenta amostras de solo foram coletadas aleatoriamente em cada área, ao final das estações seca e chuvosa e avaliadas através do método de germinação. Ao final dos experimentos, 23.651 sementes viáveis foram observadas e 80,5% destas, germinaram durante o primeiro mês. Foram encontradas 89 espécies, onde 50 delas foram de herbáceas. As famílias que mais se destacaram foram Poaceae, Cyperaceae, Euphirbiaceae, Malvaceae, Fabaceae e Solanaceae. Maior densidade de sementes ocorreu ao final da estação seca, com a área Preservada apresentando uma densidade 3,7 vezes maior que a Intermediária. O índice de diversidade de Shannon apresentou comportamento decrescente e significativo para as áreas, da estação seca para a chuvosa. Sendo assim, o banco de sementes fornece principalmente espécies pioneiras, existindo uma limitação de espécies pertencentes aos estágios mais avançados. / The presence of rivers has always been one of the primary conditions for the establishment of human groups, and the activities of these groups have caused major environmental impoverishment. In the Caatinga, where the meteorological characteristics are considered extreme and rainfall patterns are very irregular, the vegetation along the riverbanks finds itself in a situation of loss of biodiversity. Thus, the objective of this study was to generate information which could contribute in future recovery projects of riparian forests in semi-arid regions by evaluating the soil seed bank of three locations (Preserved, Intermediate, Degraded) under different land uses in a caatinga region. Forty soil samples were collected randomly in each area at the end of the dry and rainy seasons and evaluated through the germination method. At the end of the experiments, 23,651 viable seeds were observed and 80.5% of these germinated during the first month. There were found 89 species, where 50 of them were of herbaceous found. Families who stood out were Poaceae, Cyperaceae, Euphirbiaceae, Malvaceae, Fabaceae and Solanaceae. The highest density of seeds occurred at the end of the dry season, with the Preserved area featuring a density 3.7 times greater than the Intermediary. The Shannon diversity index showed decreasing behavior and significant for the areas, from the dry season to the rainy season. Thus, the seed bank primarily provides pioneer species and there is a limitation of species belonging to the most advanced stages.

L’assemblage des espèces (leurs présences/absence) dans une communauté naturelle est la conséquence de plusieurs mécanismes de filtrage réalisés par l'environnement. Parmi ces filtres, le filtre abiotique sélectionne les espèces capables de tolérer les conditions environnementales locales. La variation de la disponibilité de l'eau dans le sol est l'un des principaux gradients environnementaux selon lesquels les espèces végétales sont différemment réparties. Considérant l’hypothèse que les traits fonctionnels et leurs relations sont hiérarchisées, les préférences d’habitat des espèces le long de gradients environnementaux devraient être déterminées par une combinaison de traits physiologiques et morpho-anatomiques hiérarchisés. Au cours de ce doctorat, mon objectif général est d'identifier les traits fonctionnels morphologiques, anatomiques et physiologiques de tolérance à la sécheresse qui peuvent prédire la présence des espèces le long d'un gradient d’hydrologie des sols. Plus spécifiquement, nous cherchons à savoir : (i) Quels sont les traits physiologiques qui reflètent le mieux la tolérance à la sécheresse ? (ii) Quelles sont les relations entre les traits morpho-anatomiques et les traits physiologiques de tolérance ? (iii) Quels sont les traits morpho-anatomiques en conditions optimales permettant de prédire la tolérance des espèces herbacées à la sécheresse ? (iv) Quelles formes ont les relations qui existe entre les traits morpho-anatomiques de tolérance en condition optimale et la présence des espèces en cas de sécheresse ? (v) Peut-on prédire les présences des espèces en cas de sécheresse à partir de leurs traits morpho-anatomiques? Nos résultats montrent (1) qu’il est possible de prédire la distribution des espèces sur un gradient d’hydrologie des sols à partir de cinq traits physiologiques de tolérance à la sécheresse. Ces cinq traits sont la photosynthèse nette maximale, la conductance stomatique maximale, le potentiel hydrique du sol au point de flétrissement, la conductance stomatique au point de flétrissement et l’efficacité d’utilisation de l’eau au point de flétrissement. Nous avons montré que (ii) les traits physiologiques de tolérance à la sécheresse sont prédits par les traits morpho-anatomiques en conditions optimales (surface spécifique foliaire, teneur en matière sèche des feuilles, teneur en azote foliaire, longueur spécifique racinaire et surface stomatique). (iii) Les traits morpho-anatomiques seuls ne sont pas de bons prédicteurs de l’hydrologie des espèces et (iv) que la séquence « traits morpho-anatomiques → traits physiologiques → hydrologie des espèces » donne les meilleures prédictions. Cependant, (v) le modèle ne donne pas de prédictions fiables si l’on utilise des traits morpho-anatomiques mesurés en conditions naturelles. Ces résultats confirment, au moins partiellement, l’hypothèse que la distribution des espèces sur un gradient hydrologiques peut être prédite à partir de leurs traits de tolérance à la sécheresse eux-mêmes prédits par leurs traits morpho-anatomiques. En résumé, nous avons utilisé une approche fonctionnelle en construisant un modèle causal prédictif qui nous a permis de nous intéresser aux mécanismes de filtrage environnementaux et plus précisément au rôle de la niche hydrologique des espèces dans l’assemblage des communautés végétales. / Abstract : Species assembly (their presence/absence) in a natural community is the consequence of several filtering mechanisms made by the environment. Among these filters, the abiotic filter selects species able to tolerate local environmental conditions. Variation in water availability in the soil is one of the main environmental gradients according to which plant species are differently distributed. Considering the hypothesis that functional traits and their relationships are hierarchical, habitat preferences of species along environmental gradients should be determined by a combination of hierarchical physiological and morpho-anatomical traits. During this PhD, my overall goal is to identify morphological, anatomical and physiological drought tolerance functional traits that can predict the presence of species along a soil hydrology gradient. More specifically : (i) What are the physiological traits that best reflect drought tolerance? (ii) What are the relationships between morpho-anatomical traits and physiological traits of tolerance? (iii) What are the optimal morpho-anatomical traits for predicting tolerance of herbaceous species to drought? (iv) What forms of relationships exist between optimal morpho-anatomical traits of tolerance and the presence of species in drought condition? (v) Can the presence of species in drought condition be predicted from their morpho-anatomical features? Our results show (1) that it is possible to predict the distribution of species on a soil hydrology gradient from five physiological traits of drought tolerance. These five traits are maximum net photosynthesis, maximum stomatal conductance, water potential of the soil at the wilting point, stomatal conductance at the wilting point, and efficiency of water use at the wilting point. We have shown that (ii) the physiological traits of drought tolerance are predicted by optimal morpho-anatomical traits (leaf area, leaf dry matter content, leaf nitrogen content, root length and stomatal surface). (iii) Morpho-anatomical features alone are not good predictors of species hydrology and (iv) the sequence “morpho-anatomical traits  physiological traits  species hydrology” gives the best predictions. However (v) the model does not provide reliable predictions using morpho-anatomical traits measured under natural conditions. These results confirm, at least partially, the hypothesis that the distribution of species on a hydrological gradient can be predicted from their drought tolerance traits themselves predicted by their morpho-anatomical features. In summary, we used a functional approach by constructing a predictive causal model that allowed us to focus on environmental filtering mechanisms and more specifically on the role of the species hydrological niche in assembling plant communities.