Arid Recovery, a fenced reserve free of feral predators in arid South Australia, has successfully reintroduced two critical weight range (CWR) mammals, greater bilbies (Macrotis lagotis) and burrowing bettongs (Bettongia lesueur) to facilitate the restoration of arid Australian ecosystems. This thesis evaluates the ecological roles of these reintroduced species and their relationship to ecosystem functioning and the restoration of these ecosystems. Surveys of foraging diggings and soil seed banks, and dietary analysis were used to measure impacts of these species on three main habitats within the Reserve. The results showed that bilbies and bettongs have three major roles in ecosystem functioning: consumers, ecosystem engineers, and dispersers of seeds and fungi. Both bilbies and bettongs were omnivorous, though their diets were distinctly different, with the bilbies focused more on invertebrates and seeds, while the bettongs consumed a greater proportion of coarser plant materials. The seed portion of the diets of both species during 2003-04 differed from a similar study three years previously, shortly after the animals had been reintroduced to Arid Recovery in 2000- 01. During 2003-04, the bilbies consumed a lower proportion of seeds of species of grasses and more of forbs, while seed consumption by bettongs narrowed to be almost exclusively the seeds of shrubs. The number of bilby and bettong diggings varied significantly both spatially and temporally, with averages of 7,530 ± 820 diggings ha-1 in Dunes, 10,560 ± 980 diggings ha-1 in Mulga, and 7,120 ± 610 diggings ha-1 in Swale. This resulted in an average of 2 to 3% disturbance of soil surface area, which is similar to or higher than reported for other Australian or overseas semi-fossorial species. The temporal variation in rates of digging was correlated with minimum daily temperatures and rainfall but not moonlight. This variation was also correlated with counts of bilby but not bettong tracks, suggesting that the temporal variability of diggings was related to levels of bilby activity. The persistence of bilby and bettong diggings differed between the three habitat types, with the majority of the diggings in the Mulga (94%) and Swale (87%) persisting for over 12 months, while Dune diggings filled much faster, with only 15% persisting over 12 months. These diggings were shown to accumulate and bury seeds and litter, and, under some conditions, enhance germination. The seeds of two plant species, the annual grass, Dactyloctenium radulans, and the shrub, Enchylaena tomentosa, germinated from bilby faecal pellets, and over a third of bilby faecal pellets contained fungal spores. Therefore bilbies have the potential to be dispersers of both seeds and fungi. All three major roles of the bilbies and bettongs in ecosystem functioning (consumers, ecosystem engineers, and dispersers of seeds and fungi) have the potential to affect the flows of organic, soil and water resources, and therefore vegetation structure and overall productivity. Soil seed bank densities differed between areas with and without bilbies and bettongs. However, the heterogeneity of the system made it difficult to confidently relate these differences to any particular effects of the bilbies and bettongs. Both bilbies and bettongs were able to locate and dig seeds buried 20 cm deep, and the caches of seed-harvester ants. Experiments showed that in areas of high digging density, 71 to 94% of seed rain accumulated and became buried in diggings. Since bilbies and bettongs have the potential to use buried seed resources, they have the potential to significantly affect soil seed banks through their consumption of seeds, redistribution of seeds through their digging activities and their interactions with other granivorous species. This study is a first step towards understanding the roles of reintroducing CWR mammals to arid ecosystems. Possible longer term effects of these reintroductions will depend on suitable regulation of animal numbers, and climatic patterns, as restorative effects of diggings would be greatest during periods of good rainfall, whereas droughts would slow restorative processes. Although the results of this research are unique for Arid Recovery, the principles of evaluating all major ecological roles of reintroduced species and their interactions with their environment could provide guidance for other reintroductions. These interactions are complex and would require longer-term studies over a range of conditions and locations to further understand the role of reintroducing CWR mammals to ecological restoration. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1348600 / Thesis (Ph.D.) - University of Adelaide, School of Earth and Environmental Sciences, 2009

Arid Recovery, a fenced reserve free of feral predators in arid South Australia, has successfully reintroduced two critical weight range (CWR) mammals, greater bilbies (Macrotis lagotis) and burrowing bettongs (Bettongia lesueur) to facilitate the restoration of arid Australian ecosystems. This thesis evaluates the ecological roles of these reintroduced species and their relationship to ecosystem functioning and the restoration of these ecosystems. Surveys of foraging diggings and soil seed banks, and dietary analysis were used to measure impacts of these species on three main habitats within the Reserve. The results showed that bilbies and bettongs have three major roles in ecosystem functioning: consumers, ecosystem engineers, and dispersers of seeds and fungi. Both bilbies and bettongs were omnivorous, though their diets were distinctly different, with the bilbies focused more on invertebrates and seeds, while the bettongs consumed a greater proportion of coarser plant materials. The seed portion of the diets of both species during 2003-04 differed from a similar study three years previously, shortly after the animals had been reintroduced to Arid Recovery in 2000- 01. During 2003-04, the bilbies consumed a lower proportion of seeds of species of grasses and more of forbs, while seed consumption by bettongs narrowed to be almost exclusively the seeds of shrubs. The number of bilby and bettong diggings varied significantly both spatially and temporally, with averages of 7,530 ± 820 diggings ha-1 in Dunes, 10,560 ± 980 diggings ha-1 in Mulga, and 7,120 ± 610 diggings ha-1 in Swale. This resulted in an average of 2 to 3% disturbance of soil surface area, which is similar to or higher than reported for other Australian or overseas semi-fossorial species. The temporal variation in rates of digging was correlated with minimum daily temperatures and rainfall but not moonlight. This variation was also correlated with counts of bilby but not bettong tracks, suggesting that the temporal variability of diggings was related to levels of bilby activity. The persistence of bilby and bettong diggings differed between the three habitat types, with the majority of the diggings in the Mulga (94%) and Swale (87%) persisting for over 12 months, while Dune diggings filled much faster, with only 15% persisting over 12 months. These diggings were shown to accumulate and bury seeds and litter, and, under some conditions, enhance germination. The seeds of two plant species, the annual grass, Dactyloctenium radulans, and the shrub, Enchylaena tomentosa, germinated from bilby faecal pellets, and over a third of bilby faecal pellets contained fungal spores. Therefore bilbies have the potential to be dispersers of both seeds and fungi. All three major roles of the bilbies and bettongs in ecosystem functioning (consumers, ecosystem engineers, and dispersers of seeds and fungi) have the potential to affect the flows of organic, soil and water resources, and therefore vegetation structure and overall productivity. Soil seed bank densities differed between areas with and without bilbies and bettongs. However, the heterogeneity of the system made it difficult to confidently relate these differences to any particular effects of the bilbies and bettongs. Both bilbies and bettongs were able to locate and dig seeds buried 20 cm deep, and the caches of seed-harvester ants. Experiments showed that in areas of high digging density, 71 to 94% of seed rain accumulated and became buried in diggings. Since bilbies and bettongs have the potential to use buried seed resources, they have the potential to significantly affect soil seed banks through their consumption of seeds, redistribution of seeds through their digging activities and their interactions with other granivorous species. This study is a first step towards understanding the roles of reintroducing CWR mammals to arid ecosystems. Possible longer term effects of these reintroductions will depend on suitable regulation of animal numbers, and climatic patterns, as restorative effects of diggings would be greatest during periods of good rainfall, whereas droughts would slow restorative processes. Although the results of this research are unique for Arid Recovery, the principles of evaluating all major ecological roles of reintroduced species and their interactions with their environment could provide guidance for other reintroductions. These interactions are complex and would require longer-term studies over a range of conditions and locations to further understand the role of reintroducing CWR mammals to ecological restoration. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1348600 / Thesis (Ph.D.) - University of Adelaide, School of Earth and Environmental Sciences, 2009

The rock outcrop plants are neglected group of plants, even though they include endangered or endemic species. Despite this fact, there is only a few of studies focusing at this topic. The aim of this thesis is to focus on this group of plants in terms of its population dynamics. Aurinia saxatilis ssp. saxatilis was chosen as a model species. It is a species of the Czech thermophyticum. Three populations were chosen and studied over three years. The population dynamics was compared between the populations by integral projection modelling (IPM) and matrix population modelling (MPM). The results of these two analytical approaches were compared to one another, too. The population growth rate (λ) predicts that one of the populations is stable, whereas the other two populations are declining. The highest elasticity is mostly for the seeds survival in the seed bank. The population growth rate does not differ distinctly between the two statistical approaches, IPM and MPM. In all cases the IPM λ is lower than the MPM λ. Within the IPM analysis, the influence of the substrate type was also studied. The analyses, however, did not indicate any major differences between the substrates. For maintaining the populations, it is necessary to protect the new seeds and seedling recruitment and to create the new space...

Made available in DSpace on 2016-06-02T19:29:58Z (GMT). No. of bitstreams: 1 5454.pdf: 8508696 bytes, checksum: 427d6057ce7582f3ad197b6887b04a5e (MD5) Previous issue date: 2012-08-03 / Universidade Federal de Minas Gerais / Fire protection has caused ongoing changes in savannas throughout the world, with the expansion of the woody component over more open vegetation. Although these changes have been documented at the landscape level, some questions regarding changes in the floristic composition of communities and the regeneration mechanisms present in different physiognomies remain. The aim of this study was to evaluate species richness and abundance in several components of the community (seed rain, seed bank, and the understory, intermediate, and upper strata) in a cerrado area after 50 years of fire protection. This research was developed along the physiognomic gradient (typical cerrado, dense cerrado and cerradão) existent at Assis Ecological Station, São Paulo state. Seed rain, seed bank, and floristic composition of the three strata were sampled in 30 20 x 50 m plots, 10 plots in each physiognomy. Differences between physiognomies and between seasons were analyzed by means of uni- and multivariate analysis of variance and by linear regression and correlation. Basal area was used as a surrogate of biomass along the physiognomic gradient. Species richness decreased across the whole community for the ground layer and intermediate layer along the successional gradient. In seed rain and seed bank, the floristic composition and abundance differed significantly between the three physiognomies. In seed rain, trees and saplings, mostly generalist species, represented the predominant growth forms, both in relative abundance, as in richness. In the seed bank, herbaceous species presented the highest values for richness and abundance in all physiognomies. The seed rain and seed bank are important as regeneration strategies for a group of species, usually generalists. The homogenization of vegetation structure and floristic composition puts under question the management strategies currently employed in areas designed for Cerrado conservation. Considering that Cerrado fragmentation has concentrated its gene pool in small, isolated remnants and that some plant and animal species are restricted to more open physiognomies, a more refined discussion of the implications that management regimes may have on these communities is essential. / A proteção contra o fogo tem causado mudanças contínuas em savanas pelo mundo, com a expansão do componente arbóreo sobre fisionomias mais abertas. Essas mudanças têm sido documentadas no nível de paisagem, mas ainda persistem questões sobre as mudanças florísticas na comunidade e os mecanismos de regeneração nas diferentes fitofisionomias do Cerrado. O objetivo deste estudo foi avaliar a riqueza e abundância de espécies em diferentes compartimentos da comunidade (chuva de sementes, banco de sementes e estratos inferior, intermediário e superior) e em diferentes estações do ano em uma área de cerrado protegida do fogo há 50 anos. Esta pesquisa foi desenvolvida no gradiente fisionômico (cerrado típico, cerrado denso e cerradão) da Estação Ecológica de Assis, SP. As coletas da chuva de sementes, banco de sementes e o levantamento florístico nos três estratos da vegetação foram conduzidos em 30 parcelas de 20 × 50 m, sendo 10 parcelas para cada fisionomia. As diferenças entre fisionomias e entre estações do ano foram analisadas por meio de Análise de Variância Univariada e Multivariada e por meio de análise de correlação e regressões lineares. A área basal foi utilizada como representante da variável biomassa no gradiente fisionômico. Houve uma diminuição na riqueza para toda a comunidade (três estratos em conjunto), para o estrato inferior e para o estrato intermediário ao longo do gradiente fisionômico. Na chuva e no banco de sementes, a composição florística e a abundância diferiram significativamente entre as três fisionomias. Na chuva de sementes, as espécies arbóreas e arvoretas, em sua maioria generalistas, representaram as formas de crescimento predominantes, tanto em abundância relativa, quanto em riqueza. No banco de sementes, as espécies herbáceas apresentaram os maiores valores para riqueza e abundância, em todas as fisionomias. A chuva e o banco de sementes constituem estratégias de regeneração importantes para um grupo restrito de espécies, em geral, generalistas. O processo de homogeneização da vegetação, quanto à estrutura e composição florística, coloca sob questão as estratégias de manejo atualmente empregadas nas áreas destinadas à conservação do Cerrado. Considerando que a intensa fragmentação do Cerrado tem concentrado seu pool gênico em remanescentes pequenos e isolados e que há um conjunto de espécies de fauna e flora restritas às fisionomias mais abertas, um debate mais cuidadoso sobre as implicações de manejo para estas comunidades se faz essencial.

Made available in DSpace on 2015-03-26T12:27:01Z (GMT). No. of bitstreams: 1 texto completo.pdf: 1904414 bytes, checksum: 0f853262b604bb07ab9bdc77441a952d (MD5) Previous issue date: 2010-01-22 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / The present work was aims to realize ecologic studies in Seasonal Semideciduous Forest (initial and advanced forests) for manner to valuation the floristic composition and phytossociology, of correlations between soil factors and floristic variation, the litterfall, the seed rain and seed bank. The study was realized in Mata da Agronomia in Viçosa, MG (20°46 S e 42°52 W), individual trees with ≥ 15 cm circumference at breast height (DCH) were sampled in 20 - 25 x 10 m plots (10 plots in each site). On the sampled center was an installed quadrate litter trap with 1x1 m, where was monthly collect the material deposited between April/2007 and March/2008. Forty soil samples total in two distinct period (drought station finish and rainy station finish and arranged for germinate in wooden boxes (0,5 x 0,5 x 0,1 m) in shading of 60%. The soil samples were collected at 0-10 cm depth and submitted to chemical and physics analysis. The floristic lifting registered one total the 820 individuals were registered, once, 440 in the initial forest and 380 in the advanced forest. The families show up in richest in initial forest were Fabaceae (137), Urticaceae (45) and Sapindaceae (41) and advanced forest were Fabaceae (103), Meliaceae (49) e Flacourtiaceae (34). In the continuum the Shannon diversity index (H ) was 3.82 nat.ind.-1 and the Pielou evenness (J ) was 0.84. The initial and advanced forests revealed the low similarity among theses forests by Sorensen index. While, the canonical correspondence analysis (CCA) indicated significant correlation between the trees species availed and the fertility chemical soil. The litter production annual in the initial forest (8,349.5 kg/ha) was superior signification of advanced forest production (6,712.8 kg/ha). On the seed rain study were recognized 84 taxa, where 41 species were identified distributed among 40 families in the initial forest and 24 species belonging to 13 families in advanced forest. The life form dominate was arborous and the dispersion syndrome was zoocory. Hundred nine taxa were sampled in the seed bank the forest altogether, 101 species were identified as belonging to 73 genera distributed among 40 families, 56 species commonness in two successional stages of forest and 49 species commonness of two levy period. The herbaceous individuals predomination in all forests and valuation epoch, whit not representation the fragility of the seed bank, by little quantity inhibitor herbaceous individuals in relation to overmuch herbaceous, arboreus and arbutus individuals wat contribute for successional dynamics. / O presente trabalho teve como objetivo realizar estudos ecológicos em Floresta Estacional Semidecidual (floresta inicial e avançada) por meio da avaliação da composição florística e fitossociológica, das correlações entre os fatores edáficos e vegetacionais, da produção de serapilheira, da chuva de sementes e do banco de sementes. O estudo foi realizado na Mata da Agronomia situada em Viçosa, MG (20°46 S e 42°52 W), onde foram alocadas 10 parcelas de 25 x 10 m em cada trecho, sendo amostrados todos os indivíduos com circunferência do tronco a 130 cm do solo (CAP) ≥ 15 cm. No centro de cada parcela foi colocado um coletor de 1x1 m, no qual foi realizadas coletas mensais do material precipitado entre abril de 2007 e março de 2008. Também foram coletadas 40 amostras do banco de sementes em dois períodos distintos (final da estação seca e chuvosa) e colocadas para germinar em caixas de madeira de 0,5 x 0,5 x 0,1 m sob 60% de sombreamento. Além dessas amostras, outras foram realizadas nas parcelas (camada de 0-10 cm) e submetidas à análise química e física. No levantamento florístico registrou-se o total de 820 indivíduos, sendo, 440 registrados na floresta inicial e 380 na floresta avançada. As famílias de maior riqueza específica na floresta inicial foram Fabaceae (137), Urticaceae (45) e Sapindaceae (41) e na avançada Fabaceae (103), Meliaceae (49) e Flacourtiaceae (34). Para o conjunto, o índice de Shannon (H ) e a equabilidade (J ) foram de 3,82 nat.ind.-1 e 0,84, respectivamente. As florestas inicial e avançada apresentaram baixo índice de similaridade florística. A análise de correspondência canônica (CCA) indicou correlação significativa entre a distribuição das espécies arbóreas avaliadas no perfil topográfico e a fertilidade do solo. A produção anual de serapilheira na floresta inicial (8349,5 kg/ha) foi significativamente superior à produção da floresta avançada (6712,8 kg/ha). No estudo de chuva de sementes foram reconhecidos 84 taxa, sendo 41 espécies pertencentes a 25 famílias na floresta inicial e 24 espécies pertencentes a 13 famílias na floresta avançada. A forma de vida dominante foi arbórea e a síndrome de dispersão predominante foi a zoocórica. No estudo do banco de sementes foram registrados 109 taxa no banco de sementes da floresta como um todo, sendo reconhecidas 101 espécies distribuídas em 73 gêneros de 40 famílias. Ocorreram 56 espécies comuns aos dois trechos de floresta e 49 espécies comuns aos dois períodos de coleta. Os indivíduos herbáceos predominaram em todas as florestas e épocas de avaliação, o que não representou a fragilidade do banco de sementes, pela pequena quantidade de invíduos herbáceos inibidores em relação aos demais herbáceos, arbóreos e arbustivos que contribuem para a dinâmica sucessional.

Made available in DSpace on 2015-05-14T12:17:28Z (GMT). No. of bitstreams: 1 parte1.pdf: 2181706 bytes, checksum: c9955f222106de763afe071b312bcaf3 (MD5) Previous issue date: 2011-02-25 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The valorization of the cultivation of sustenance is related to the construction of new territories, strengthened by various local cultures, in many cases, assigned to a mystical value, social, historical, political and economical. In Brazil, mainly in the Northeast, the tradition of seed storage today reduced due to new techniques introduced by agricultural modernization is a form of guarantee power in times of drought and of quality seeds for planting at the right time. This thesis aims to analyze a form of pleasant resistance to the process of capital‟s domination in the agriculture, the Seed Bank comunities (BSC acronyn in Portuguese), through the case study of BSC from settlement called Três Irmãos. To do this, we highlight as specific objectives: a) to debate the meanings on the territory, rural development and sustainable agricultural practices, while categories of theoretical reasoning and analysis; b) redeem the historical process of territorial from Sertão of Paraíba - one region from the state- formation in the light of uneven development of capitalism and combined in the field; c) retrieve and discuss the historical process of construction of the territory of the settlement and BSC Três Irmãos (Triunfo PB); d) understand the social, economic, cultural and political dynamics of seed banks and their reflections on the territories. The locus of research was the settlement Três Irmãos composed of 74 families, distributed in 6 parts: Três Irmãos, Mulunguzinho, Tabuleiro Grande, Cróa and Vertente, located in the microregion of Cajazeiras. Choosing this Settlement occurred due to the fact he was the first in the Sertão of Paraiba to develop a Community seed bank in the 1990s being the third in Brazil. The methodology used was a case study of quantitative and qualitative approach with emphasis on second. Data collection was performed from Exploratory Research interviews, testimonials of family farmers, people from NGOs and technicians, plus comments, field visits and attendance at events. The Paper is divided into four chapters, besides the introduction and final considerations. It is concluded that seed storage represents a form of resistance to negative impacts on the field, caused by the prevailing capitalist model; Furthermore, it contributes to the strengthening of territories of hope by sharing knowledge and seeds to farmers about their localities; also, collaborates with the rescue of new and old peasant production techniques, in Paraíba, which culminates in the State Party of Seed of Passion. / A valorização do cultivo de alimentos está relacionada à construção de novos territórios, fortalecidos por diversas culturas locais, em muitos casos, atribuídos a um valor místico, social, histórico, político e econômico. No Brasil, principalmente no Nordeste, a tradição da estocagem de sementes - hoje reduzida devido às novas técnicas introduzidas pela modernização agrícola - é uma forma de garantia de alimentação em tempos de estiagem e de sementes de qualidade para o plantio na época certa. Esta dissertação objetiva analisar uma forma de resistência camponesa ao processo de dominação do capital na agricultura, o Banco de Sementes Comunitário, através do estudo de caso do BSC do Assentamento Três Irmãos. Para isso, elencamos como objetivos específicos: a) rediscutir as acepções sobre território, desenvolvimento rural e práticas agrícolas sustentáveis, enquanto categorias de fundamentação e análise teórica; b) resgatar o processo histórico de formação territorial do Sertão paraibano à luz do desenvolvimento desigual e combinado do capitalismo no campo; c) recuperar e discutir o processo histórico de construção do território do Assentamento e do BSC Três Irmãos (Triunfo - PB); d) entender a dinâmica social, econômica, cultural e política dos Bancos de Sementes e seus reflexos sobre o território. O locus da pesquisa foi o Assentamento Três Irmãos, composto por 74 famílias, distribuídas em 06 glebas: Três Irmãos, Mulunguzinho, Saco, Tabuleiro Grande, Croá e Vertente, localizadas na microrregião de Cajazeiras. A escolha desse Assentamento ocorreu devido ao fato dele ter sido o primeiro, no Sertão Paraibano, a desenvolver um Banco de Sementes Comunitário, na década de 1990, sendo o terceiro do Brasil. A metodologia utilizada foi um estudo de caso, de abordagem quanti-qualitativa, com ênfase à segunda. A coleta de dados foi realizada a partir de entrevistas semiestruturadas, depoimentos de agricultores familiares, agentes de ONGs e técnicos, além de observações, visitas de campo e participação em eventos. O trabalho está dividido em quatro capítulos, além da introdução e das considerações finais. Conclui-se que a cultura de estocagem de sementes representa uma forma de resistência aos impactos negativos no campo, causados pelo modelo capitalista vigente; Ademais, contribui para o fortalecimento dos territórios de esperança através da partilha de sementes e dos conhecimentos dos camponeses sobre suas localidades; também, colabora com o resgate de novas e antigas técnicas de produção camponesa que, na Paraíba, culmina na Festa Estadual da Semente da Paixão.

Orientador: Carlos Alfredo Joly / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-10T11:35:16Z (GMT). No. of bitstreams: 1 Souza_SilvanaCristinaPereiraMunizde_D.pdf: 1575660 bytes, checksum: 98a9f7bfb573c6e75828a881cb9c32dd (MD5) Previous issue date: 2008 / Resumo: O banco de sementes da comunidade, a estrutura e a dinâmica populacional de espécies de diferentes grupos ecológicos, definidos de acordo com a tolerância à sombra, foram avaliados em um trecho de Floresta Ombrófila Densa Submontana. Os objetivos do estudo foram investigar a dinâmica, composição e as características das espécies presentes no banco de sementes; descrever a estrutura e a dinâmica populacional das seguintes espécies arbóreas: i) três colonizadoras de bordas e clareiras - Alseis floribunda, Bathysa australis e Rapanea hermogenesii; iii) três típicas de dossel - Chrysophyllum viride, Quiina glaziovii e Tetrastylidium grandifolium; iii) seis típicas de subosque - Eugenia cuprea, Garcinia gardneriana, Guapira opposita, Handroanthus serratifolius, Inga marginata e Rudgea jasminoides. A área de estudo localiza-se no interior de uma parcela permanente de 10 ha, subdividida em 256 sub-parcelas de 20 x 20 m, instalada no Parque Estadual de Carlos Botelho (24°00¿ a 24°15¿S, 47°45¿ a 48°10¿W), município de Sete Barras, São Paulo. Foram sorteadas 25 sub-parcelas, em cada uma das quais foram coletadas três amostras de solo de 0,25 x 0,25 m, com 0,05 m de profundidade, em março e setembro de 2004 e 2005. As amostras foram incubadas por seis meses, em casa de vegetação sob 70% da luminosidade total. Nas subparcelas sorteadas todos os indivíduos das espécies escolhidas, com altura > 3 cm, foram etiquetados e tiveram registrados a altura e o diâmetro do caule no nível do solo (DAS), em 2004 e 2005. Analisou-se a distribuição dos indivíduos em classes de DAS e altura e calculou-se: coeficiente de Gini, mortalidade, recrutamento e crescimento. Do banco, germinaram 3.204 sementes (170,9 ± 42,6 sem.m-2), de 93 espécies. Dentre as espécies árboreas germinadas, 21 (97,0% do total de sementes germinadas) são intolerantes à sombra e 13 (3,0% do total de sementes germinadas) são tolerantes. Os resultados confirmaram a hipótese de que as espécies arbustivas e arbóreas do banco de sementes desta formação florestal são, predominantemente, intolerantes à sombra e zoocóricas. Em relação às estruturas de tamanho, mais de 60% de todos os indivíduos concentraram-se na classe de menor tamanho e todas as espécies apresentaram valores de Coeficiente de Gini superiores a 0,49, indicando baixa equabilidade de tamanhos (alta hierarquia). Apenas duas espécies apresentaram incremento populacional no período, ambas de subosque - Inga marginata (0,04) e Rudgea jasminoides (0,05) e os maiores descréscimos foram de Chrysophyllum viride (-0,17) e Tetrastylidium grandifolium (-0,12), devido a altas taxas de mortalidade e baixo recrutamento. O crescimento em altura e diâmetro não diferiu entre os grupos ecológicos. No entanto, foi observada uma tendência de maior crescimento em altura e diâmetro com o aumento da classe de tamanho para todas as espécies. Portanto, não foi possível estabelecer uma relação direta entre a estrutura de tamanho e tolerância à sombra para as populações estudadas e os descritores de dinâmica utilizados. Mortalidade, recrutamento e crescimento não indicaram diferenças entre os grupos ecológicos que justifiquem a separação das espécies realizada a priori, reforçando a idéia que os agrupamentos de espécies mascaram diferenças inter e intra-específicas / Abstract: The community seed bank, the structure and population dynamics of species belonging to different ecological groups, defined according to their shade tolerance, were evaluated on a stand of Submontane Ombrophilous Dense Forest. The aims of this study were to investigate the dynamics, composition and characteristics of the species present in the seed bank; to describe the structure and the population dynamics of the following tree species: i) three edge and gap colonizers - Alseis floribunda, Bathysa australis, Rapanea hermogenesii; ii) three typical of the canopy - Chrysophyllum viride, Quiina glaziovii and Tetrastylidium grandifolium; iii) six typical of the understory - Eugenia cuprea, Garcinia gardneriana, Guapira opposita, Handroanthus serratifolius, Inga marginata and Rudgea jasminoides. The studied area is located within a 10 ha permanent plot, subdivided into 256 20 X 20 m sub-plots, installed in the Carlos Botelho State Park 24°00¿ a 24°15¿S, 47°45¿ a 48°10¿W), Sete Barras municipality, São Paulo state. Twenty-five sub-plots were randomly selected, and in each of these sub-plots three 0.25 X 0.25m soil samples, 0.05 m deep, were collected, in March and September 2004 and 2005. Those samples were incubated for six months, in a green house, under 70% of total light. In the selected subplots all individuals of the chosen species that were _ 3 cm in height, were tagged and measured for their height and trunk diameter at ground level (DGL), in both years. Distribution of individuals among DGL and height classes was analyzed and Gini coefficient (G), mortality, recruitment and growth rate were calculated. 3,204 seeds from the seed bank germinated (170,9 ± 42,6 seeds.m-2), of 93 species. From the tree species that germinated, 21 (97% of the total germinated seeds) are shade intolerant and 13 (3% of the total germinated seeds) are shade tolerant. The results confirm the hypothesis that shrub and tree species that form seed bank in this specific type of forest are predominantly shade intolerant and zoocoric. Concerning size structures, more than 60% of all individuals were concentrated in the smallest size class and all species presented Gini Coefficient higher than 0.49, indicating low size evenness (high hierarchy). Only two species showed population increment in the period, both from the understory, Inga marginata (0.04) and Rudgea jasminoides (0.05) and the most expressive decrease were found in Chrysophyllum viride (-0.17) e Tetrastylidium grandifolium (-0.12), due to high mortality rate and low recruitment. Height and diameter growth did not differ among the ecological groups. However, it was observed a tendency for an increased height and diameter growth related to increase in the size class for all species. Hence, it was not possible to establish a direct relation between size structure and shade tolerance for the studied populations and the dynamics descriptors used. Mortality, recruitment and growth, did not indicate differences among the ecological groups that justify the division of species done a priori, reinforcing the idea that species grouping conceal inter and intra-specific differences / Doutorado / Biologia Vegetal / Doutor em Biologia Vegetal

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Many researches have been focused on reforestation projects, taking advantages on the self recuperation mechanism of the frorest such as seed rain, soil seed bank and seedling banks. Seed rain is an initial process which develops the dynamic, organization and structuration of the forest. However, the seed bank is one of the most important factors for natural recolonization of affected areas which start the succession process. Through this natural regeneration, a set of individuals are able to be recruited to the upper stages. In this way, the present study was performed aiming to evaluate the plant species establishment strategies through natural regeneration, in an area in the city of Laranjeiras-SE. Thirty plots were installed, and in center of these plots, collectors were installed (1m x 1m) to estimate the seed rain. To characterize the seed bank, was collected from August 2014 (corresponding to the rainy season in the region) to February 2015 (dry season), a soil sample from the center of each subplot (1m x 1m) through a metal jig which was introduced into the soil to remove a 5 cm layer. In the seedling bank evaluation, height and diameter of seedlings were analyzed between August 2014 (rainy season) and Februare 2015 (dry season) in subplots (1m x 1m). In seed rain were found 7,788 seeds, in which Shinus terebinthifollius Raddi (aroeira) presented a higher number of seeds collected with 6,799 samples and its frequency was 87.84% in relation with others species. The autochoric syndrome of dispersion was observed to Centrosema brasilianum (L.) Benth., Fabaceae 2 and Anadenanthera colubrina (Vell.) Brenan, for Asteraceae 1 and Bignoniaceae 1 the dispersion syndrome observed was anemocoric and to Schinus terebinthifollius and Passiflora mansoi (Mart.) Mast, the dispersion syndrome was zoochoric. In the study of seed bank, it was found a total of 171 seeds. The seed bank analyzes by the rainy season and dry season, Schinus terebinthifollius prevailed with more individuals in the rainy season. However, Fabaceae sp prevailed in the dry season. The distribution of species per plot was heterogeneous in both seasons, but presented a better distribution in the rainy season. In the study of seedlings bank, samples were found belonging to seven families and thirteen species. Shinus terebinthifollius represented 28% of total specimen, followed by Genipa Americana L. with 20%. The rainy season showed better seedling distribution along the plots. The processes of natural regeneration at studied area have presented a diversity of species into three regeneration kinds evaluated in different fructification seasons, establishing int this way, a steady supply of seeds, enabling the development of new individuals for future process. / Inúmeras pesquisas têm sido voltadas a projetos de reflorestamentos, aproveitando o próprio mecanismo de recuperação da floresta como chuvas de sementes, bancos de sementes do solo e bancos de plântulas. A chuva de sementes é um processo inicial que desenvolve a dinâmica, organização e estruturação da floresta. No entanto, o banco de sementes é um dos fatores mais importantes para a recolonização natural das áreas afetadas dando início ao processo sucessional. Por meio dessa regeneração natural, um conjunto de indivíduos são capazes de ser recrutados para os estádios superiores. Dessa forma, o presente trabalho foi realizado objetivando avaliar as estratégias de estabelecimentos das espécies vegetais por meio da regeneração natural, numa área em reflorestamento, no município de Laranjeiras-SE. Foram instaladas 30 parcelas, e no centro dessas parcelas foram instalados coletores (1m x 1m) para estimar a chuva de sementes. Para a caracterização do banco de sementes, foi coletada, no mês de agosto de 2014 (correspondente a estação chuvosa na região) e fevereiro de 2015 (estação seca), uma amostra de solo no centro de cada subparcela (1m x 1m), através de um gabarito metálico que foi introduzido no solo para remover uma camada de 5 cm. Na avaliação do banco de plântulas, foram realizadas análises de altura e diâmetro das plântulas, entre agosto de 2014 (estação chuvosa) a fevereiro de 2015 (estação seca), em subparcelas (1m x 1m). Na chuva de sementes foram encontradas 7.788 sementes, dentre as quais a espécie Schinus terebinthifollius Raddi (aroeira) apresentou maior número de sementes coletadas, com 6.799 amostras possuindo frequência de 87,84% em relação as outras espécies. A síndrome de dispersão autocórica foi observada para as espécies Centrosema brasilianum (L.) Benth., Fabaceae 2 e Anadenanthera colubrina (Vell.) Brenan, para Asteraceae 1 e Bignoniaceae 1 a síndrome de dispersão observada foi anemocorórica e para as espécies Schinus terebinthifollius e Passiflora mansoi (Mart.) Mast, a síndrome de dispersão presente foi a zoocórica. No estudo do banco de sementes, foi encontrado um total de 171 sementes. Nas análises por estação chuvosa e seca do banco de sementes, a espécie Schinus terebinthifollius prevaleceu com maior número de indivíduos na estação chuvosa. Contudo, prevaleceu a espécie Fabaceae 1 na estação seca. A distribuição das espécies por parcela foi heterogênea em ambas as estações, porém apresentou uma melhor distribuição no período chuvoso. No estudo do banco de plântulas, foram encontradas amostras pertencentes a sete famílias e treze espécies. A espécie Schinus terebinthifollius representou 28% dos espécimes amostrados, seguida por Genipa americana L. com 20%. Na estação chuvosa houve uma melhor distribuição de plântulas ao longo das parcelas. O processo de regeneração natural da área de estudo apresentou uma diversidade de espécies nas três formas de regeneração avaliadas com diferentes épocas de frutificação, estabelecendo assim, uma constante oferta de sementes, viabilizando o desenvolvimento de novos indivíduos para processos futuros.

Tradicionalmente o manejo das plantas daninhas é realizado levando-se em consideração a infestação média destas plantas nas áreas agrícolas; sendo então adotadas estratégias de manejo de forma homogênea em toda a área. Porém, as plantas daninhas não se distribuem uniformemente, sendo comum o comportamento contagioso, formando manchas ou “reboleiras”. No entanto, a localização e mapeamento de diferentes infestações são tarefas difíceis de serem executadas em larga escala e requerem metodologias adequadas. Desta forma, métodos de determinação dessa variabilidade espacial necessitam de melhores esclarecimentos e estudos científicos. Com o objetivo de estudar o comportamento da variabilidade espacial das plantas daninhas e seu respectivo banco de sementes com a utilização de ferramentas da agricultura de precisão, foram realizados quatro experimentos para avaliar esta variabilidade espacial e temporal e analisar a potencialidade que a mesma pode proporcionar para o manejo racional das plantas daninhas, principalmente a possibilidade da aplicação localizada de herbicidas. O primeiro experimento consistiu do mapeamento do banco de sementes ao longo de dois anos consecutivos no intuito de comparar sua variabilidade espacial com a flora emergente. Concluiu-se que existe uma correlação entre o banco de sementes e a flora emergente e entre bancos de sementes de anos consecutivos, principalmente para as plantas daninhas Ageratum conyzoides L. e Commelina benghalensis L.. Analisando a dependência espacial, foi detectada uma dependência entre 7 e 15 m para o banco de sementes e a flora emergente. Os mapas gerados mostraram uma grande variabilidade espacial das plantas daninhas, sendo observadas algumas tendências de estabilidade ao longo do tempo. No segundo experimento foram feitos dois mapeamentos da infestação da planta Panicum maximum Jacq., um durante a colheita da cultura de milho e outro após a colheita, para fins de aferição do método de mapeamento realizado durante a colheita. Foi constatada uma subestimação de 6% da área infestada pelo método de mapeamento durante a colheita, quando este foi comparado com o caminhamento numa grade regular após a colheita. Os dois métodos foram coincidentes em 45% das áreas marcadas. O terceiro experimento consistiu de uma avaliação da eficácia da aplicação localizada de herbicidas pós-emergentes na cultura da soja, baseada em mapas de infestação das plantas daninhas. Para isto foi feito uma amostragem numa grade de 6 x 6 m e, baseado na infestação em cada célula, foi pulverizado duas doses de herbicidas pós-emergentes dependendo da infestação de cada local. Foi obtida uma economia de produto da ordem de 18 e 44%, sendo a eficácia similar à aplicação convencional utilizando dose única e pulverização uniforme em área total. No quarto experimento foi realizada uma pulverização localizada de herbicida pré-emergente baseada no mapeamento prévio do banco de sementes das plantas daninhas; sendo verificado uma eficácia igual à convencional e uma economia de 22% de produto herbicida. Portanto, técnicas de mapeamento da variabilidade espacial das plantas daninhas são importantes ferramentas para que melhores decisões sejam tomadas dentro dos sistemas de produção agrícola, sendo de extrema urgência um maior conhecimento e embasamento técnico-científico de técnicas agronômicas que considerem esta variabilidade espacial. / Traditionally the weed management has been done considering the overall weed infestation in the whole field and then herbicides are sprayed according to a single weed control recommendation for the field. But weeds are not uniformly distributed and normally have clumped populations showing weed patches presenting high spatial variability. This nature of the weed populations can be mapped, and so it can help the decisions associated with weed management on agricultural systems. However, localization and mapping of the weed clusters are very difficult tasks in large areas, and require adequate methodology. Therefore, determination method of this weed infestation variability in space must be scientifically studied. With the objective of studying the weed spatial variability and temporal behavior of weed seedlings infestations and their respective seed banks, four experiments were conducted to evaluate the spatial temporal behavior of the weeds and the potential of weed mapping technology could bring to the rational weed management. The aim of the first experiment was to evaluate the spatial temporal behavior of the weed seedlings and their respective seed banks using the mapping technology. A grid sampling was used to understand the seedling and seed bank behavior in the space and time. Correlations using “Spearman rank” test were observed, mainly in Ageratum conyzoides L. and Commelina benghalensis L. The spatial dependence was noted between 7 and 15 m for the weed seedlings and seed banks. The weed maps showed that the weeds have a high spatial variability making patches with some temporal stability. In the second experiment two weed surveys were done with the objective of mapping Panicum maximum Jacq. during and after corn harvest. The grid sampling method after harvest corn was used to evaluate the harvest mapping method. It was underestimated about 6% of the weed infestation using the harvest mapping method when it was compared with the grid sampling method after corn harvest. In this experiment the harvest mapping method had just 45% of efficiency in recording weed infestation areas. The third experiment was done in order to analyzed the post emergence herbicide efficacy in soybeans based on weed maps constructed with grid sampling mapping. The weed seedling was counted in a 6 by 6 m grid and, based on weed infestation of each grid, it was sprayed two post emergence herbicide rates according to the weed infestation. It was saved 18 to 44% of herbicides compared to broadcast application with the same herbicide efficacy. In the fourth experiment a pre emergence herbicide application was carried out in soybeans crop based on weed seed bank map and, it was observed that the site-specific application had similar efficacy saving 22% of herbicides. So, the weed mapping technology is an important tool to bear on decisions associated with crop production, and it is a priority for the implementation of this technology multiple sources of scientific knowledge in weed biology and management regarding to the weed spatial variability.

Thesis (M.Sc. Agriculture (Pasture Science)) -- University of Limpopo, 2021 / Savanna rangelands are ecosystems which are characterized by the co-existence of scattered trees and shrubs with a continuous grass layer. However, the grass and tree balance has been highly altered as a result of disturbances caused by bush encroachment. Encroaching woody species have been shown to decrease species richness and abundance of the seed bank and ground‐layer diversity. So far little is known on the effect of bush encroachment and soil depth on the soil seed bank diversity in savanna rangelands. The objectives of this mini-dissertation were to (1) determine the influence of soil depth on soil seed bank diversity in bush encroached savanna rangelands, and (2) determine the relationships between soil seed bank herbaceous vegetation and physicochemical properties in encroached rangeland. In order to address these objectives, a savanna rangeland was demarcated into two encroachment gradients spanning from open to encroached rangeland. Within each encroachment gradient, six plots of 10 m x 10 m were randomly selected, whereby soil sampling and herbaceous vegetation were carried out and determined. In each replicate plot per encroachment level, five soil samples were randomly collected at 0-10 and 10-20 cm depths. The number of seedlings of different species emerging from the soil samples was used as a measure of the number of viable seeds in the soil and the composition of the seed bank using the seedling emergence method. The total seed densities showed significant differences (P<0.05) in the 0-10 cm depth layer in the open rangeland and encroached rangeland. Bush encroachment significantly (P<0.05) decreased the seed density of perennial grasses, specifically in 0-10 cm depth layer. Further, species diversity increased with bush encroachment in the 10-20 cm depth layer. Menhinick’s richness index showed no significant difference in the open and encroached rangeland, while species evenness decreased in the 0-10 cm depth layer and increased at 10-20 cm depth.The study also revealed negative correlations between organic carbon, calcium, clay, silt and forbs while mean weight diameter (MWD), a measure of soil aggregate stability was positively correlated with forbs. The canonical correspondence analysis (CCA) showed that pH, phosphorus, potassium and calcium were positively correlated to Eragrostis curvula and magnesium was negatively correlated to Panicum maximum. In open rangeland, CCA revealed that clay content was negatively correlated with species evenness while xii magnesium was negatively correlated to the Shannon Weiner index. Further, silt content was positively correlated with species richness and evenness. In the encroached rangeland, the CCA showed a negative correlation between magnesium and the Shannon Weiner index. The Sørensen’s index between soil seed banks and aboveground vegetation was low with index values of 0.22 and 0.24 in open and encroached rangeland, respectively. / AgriSeta