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Fish harvest and replacement of top piscivorous predators in aquatic food webs: implications for restoration and fisheries managementMcGregor, Andrea M Unknown Date
No description available.
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Characterisation of the hydrological processes and responses to rehabilitation of a headwater wetland of the Sand River, South Africa.Riddell, Edward Sebastian. January 2011 (has links)
The erosion of headwater wetlands in the Sand River catchment, in the lowveld of north-eastern South Africa has led to a focus on their rehabilitation, both for livelihood security for those that use them for subsistence agriculture, as well as for provision of streamflow regulation services for the Sand River itself. One such wetland, the Craigieburn-Manalana itself undergoing severe erosion was subject to technical rehabilitation using concrete weirs and gabion dams to stabilize the erosion gullies during 2007. Through a series of papers the research discussed in this thesis examined the response of the wetland?s hydrodynamics to the implementation of these measures. Through the installation of a network of hydrometric apparatus the research has shown that the wetlands hydrology is largely controlled by the presence of both horizontal and vertical clay aquicludes within a hydraulically conductive sandy matrix. The sequence of these aquicludes had allowed for artesian phreatic surface phenomena identified in a relatively hydrologically intact region of the wetland. The gully erosion had initiated hydraulic drawdown of the wetland?s water table leading to the desiccation of the system. The construction of a buttress weir within the erosion gully had restored the wetlands hydrodynamics to that typical of conditions upstream of a clay-plug. The research also explored the role that clay plays in terms of controlling the wetland?s hydro-geomorphic setting through geophysical analysis. A conceptual model was then derived that states that these wetlands are held in place by clay-plugs that form through clay illuviation from the hillslopes at regions of valley confinement. This has important implications for the connectivity of wetland process domains. The research also determined the inputs of surface and subsurface flows to the wetland and it was found through detailed examination of soil moisture responses and variably saturated soil physics modelling using the HYDRUS model, that the wetland is hydrologically connected to its contributing hillslope by threshold induced preferential flow pathways, via macropores, that only respond after specific antecedent soil moisture conditions are met. In addition, the thesis describes novel approaches to use information provided by soil scientists for the development of catchment hydrological models. It was shown that the use of this hydropedology information improved the low flow response function of the catchment model, ACRU. This development has important implications for up-scaling of catchment process domains, or hydrological response units by being able to generalize on hillslope hydrological responses based on configuration of their soil type elements. The research also undertook to examine the role that the wetlands play in catchment processes. It was found through water budgeting, supported by hydrological time-series, stable isotope analysis and the quantification of vegetation water use within the wetland and contributing catchment, that these wetlands do not augment baseflows during the dry season. Furthermore, it is only early on during the wet season that these systems may attenuate peak flows, thereafter they act as conduits for high storm flows. Similarities emanated from this research with previous hydrological studies of headwater wetland systems in southern Africa and these are discussed. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2011.
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The role of the reintroduction of Greater Bilbies (Macrotis lagotis) and Burrowing Bettongs (Bettongia Lesueur) in the ecological restoration of an arid ecosystem: foraging diggings, diet, and soil seed banks.Newell, Janet January 2009 (has links)
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
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The role of the reintroduction of Greater Bilbies (Macrotis lagotis) and Burrowing Bettongs (Bettongia Lesueur) in the ecological restoration of an arid ecosystem: foraging diggings, diet, and soil seed banks.Newell, Janet January 2009 (has links)
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
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The value of ecological restoration volunteer programs a case study in Western Washington State /Langenfeld, Catherine. January 1900 (has links) (PDF)
Thesis (M.E.S.)--Evergreen State College, 2009. / "March 2009." Title from title screen (viewed 4/8/2010). Includes bibliographical references (p. 101-105).
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Processus et dynamique de la recolonisation et de la bio-diversité dans les bras du Rhin et autres cours d'eau restaurés de la plaine d'Alsace après reconnexion / Processes and dynamics of recolonization and biodiversity in side-channels of the Rhine river (France) and other restored streams after reconnectionMeyer, Albin 12 December 2012 (has links)
Durant les 20 dernières années d'anciens bras latéraux du Rhin ont été restaurés par reconnexion au cours principal. L'objectif de cette thèse est d'évaluer l'efficacité de la restauration et de vérifier si l'écosystème aquatique a retrouvé sa fonctionnalité. Les communautés végétales aquatiques sont utilisées ici comme indicateurs de ces changements. De nombreux facteurs ont été mesurés : les communautés végétales, leurs traits biologiques, les flux et stocks de diaspores, la chimie de l'eau, du sédiment et des plantes, l'hydro-géomorphologie. Cette étude a été menée dans 9 sites restaurés et 3 sites de référence. Trois communautés végétales ont été identifiées : une "eutrophe", une "mésotrophe", et une "rhéophile". La composition de ces communautés est liée aux conditions physiques et trophiques, et aux flux de diaspores. Les reconnexions ont permis aux sites restaurés de retrouver des communautés et une fonctionnalité écologique semblables à celles des sites de référence. / During the last 20 years, side channels of the Rhine have been reconnected to the main course. The objective of this thesis is to assess the efficiency of restoration and the recovery of the ecosystems functionality. The aquatic plant communities were used as indicators of changes. Many factors were monitored: plant communities, their biological characteristics, flux and bank of propagules, the chemistry of water, sediment and plants, hydro-geomorphology. This study was conducted in 9 restored sites and 3 reference sites. Three aquatic plant communities were identified: eutrophic, mesotrophic and rheophilic. The composition of these communities is first linked to physical conditions and second to trophic level, together with flux of propagules. Reconnections allowed the restored sites to exhibit communities and ecological functioning similar to reference sites, in a relatively short time.
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Trajetórias sucessionais e fatores condicionantes na restauração de matas ciliares em região de floresta estacional semidecidual / Successional trajectories and conditioning factors in the restoration of riparian semideciduous forestMarcio Seiji Suganuma 04 April 2013 (has links)
O número de projetos de restauração de ecossistemas florestais no Brasil aumentou nas últimas décadas e, consequentemente, aumentaram as exigências na avaliação e na busca por indicadores de sucesso. Apesar dos avanços na ecologia da restauração, existem lacunas no conhecimento em relação ao funcionamento e à autossustentabilidade dos ecossistemas restaurados. Esta pesquisa teve o objetivo de responder às seguintes questões: (1) É possível detectar padrões nos atributos de riqueza, estrutura e grupos funcionais nas matas ciliares nativas da Floresta Estacional Semidecidual (FES), que podem ser utilizados como metas da restauração florestal nesta região? (2) Quais as variáveis de biodiversidade, estrutura florestal e grupos funcionais, nas áreas restauradas, que seguem trajetórias previsíveis com o tempo? (3) Quanto tempo é necessário para que estas variáveis atinjam os valores de referência das matas ciliares nativas? (4) Quais são os fatores bióticos, abióticos, de técnica de plantio e de manutenção pós-plantio que influenciam nas trajetórias das matas ciliares restauradas? O estudo foi desenvolvido em região de FES, onde amostramos quatro matas nativas (referências) e 26 plantios de restauração, com idade entre quatro e 53 anos, que utilizamos para modelar as trajetórias em cronoseqüência. Em cada área, dez parcelas de 100 \'M POT.2\' foram aleatoriamente distribuídas, dentro de uma faixa de até 50 m de largura a partir da margem. Identificamos e contabilizamos os indivíduos de espécies arbóreas e arbustivas, plantadas ou regenerantes, a partir de 50 cm de altura e os agrupamos em três classes de tamanho segundo o diâmetro à altura do peito (DAP): DAP < 1 cm, 1 cm \'< ou =\' DAP < 5 cm e DAP \'> ou =\' 5 cm. Na classe de maior tamanho registramos o DAP e estimamos a altura de cada indivíduo. Classificamos as espécies de acordo com a sua síndrome de dispersão, ritmo de crescimento, tolerância à sombra, capacidade de fixar N, grau de ameaça e raridade. Para cada parcela, medimos a abertura do dossel, contabilizamos o número de lianas, pteridófitas e árvores com epífitas e coletamos uma amostra de solo, para formar uma amostra composta para cada local de estudo. Calculamos a biomassa acima do solo para árvores com DAP \'> ou =\' 5 cm, a riqueza total estimada por Jackknife e a riqueza rarefeita para 100 indivíduos. Por meio de entrevistas, observações em campo e análises da paisagem, obtivemos dados representativos de fatores abióticos, bióticos e de manejo que poderiam influenciar as trajetórias das comunidades arbóreas restauradas. Modelamos a trajetória de cada variável relativa à comunidade arbustivo-arbórea em função do tempo e estimamos o tempo que será necessário para igualar os ecossistemas de referência para cada variável. Entre as variáveis analisadas, selecionamos, como indicadores para monitoramento da evolução e sustentabilidade do ecossistema restaurado, as que fossem mais previsíveis (melhor qualidade dos modelos) e que representassem processos ecológicos mais relevantes. Os atributos que não variaram entre florestas nativas e que puderam ser utilizados como referência foram: riqueza observada, riqueza estimada para 100 indivíduos com DAP \'> ou =\' 5 cm, riqueza estimada por Jackknife para indivíduos com DAP \'> ou =\' 1 cm, densidade de indivíduos com DAP \'> ou =\' 1 cm, área basal, biomassa, cobertura de copas, proporção de indivíduos tolerantes à sombra e proporções de espécies zoocóricas, de crescimento lento, tolerantes à sombra, fixadoras de nitrogênio e de distribuição rara. No geral, as trajetórias foram mais bem ajustadas aos modelos logarítmicos, mas a riqueza de regenerantes de maior tamanho (DAP \'> ou =\' 5) ajustou-se melhor ao modelo linear. A riqueza nesta classe de tamanho não atingiu o nível de regenerantes dos ecossistemas de referência no período estudado. As trajetórias seguiram padrões semelhantes, independentes das técnicas de plantio ou do número de espécies plantadas. Variáveis de estrutura florestal foram homogêneas entre as matas nativas. Nos plantios, são facilmente medidas e evoluem rapidamente. Assim, metas da restauração podem ser estabelecidas com base nos parâmetros estruturais das matas nativas e tais variáveis seriam bons indicadores inclusive em plantios de restauração mais jovens. As variáveis que tendem a alcançar mais rapidamente os valores de referência são: área basal (12 anos), biomassa (13 anos), altura média das maiores árvores (26 anos), cobertura de gramíneas (33 anos), cobertura de copas (35 anos), riqueza de regenerantes com DAP \'> ou =\' 1 cm (52 anos), densidade de regenerantes com DAP \'> ou =\' 1 cm (52 anos) e riqueza total (53 anos). A área basal e a biomassa ultrapassaram em muito os valores de referência, o que pode indicar um filtro restritivo para a regeneração natural, caso a densidade dos indivíduos na classe de maior tamanho (geralmente plantados) não diminua naturalmente com o tempo. Para alguns grupos de espécies (zoocóricas, fixadoras de N, espécies raras e ameaçadas), as proporções em termos de riqueza e de densidade não apresentaram trajetórias previsíveis, mas algumas matas ciliares restauradas atingiram e ultrapassam os valores de referência. Excluímos o fator idade para identificar os fatores que influenciaram as trajetórias das variáveis selecionadas como indicadores, calculando um índice de sucesso (proporção entre o dado observado em cada local e o estimado para a mesma variável com base no modelo). Entre as seis variáveis selecionadas como indicadores, uma foi influenciada somente pela distância de fragmento-fonte (riqueza de regenerantes com DAP \'> ou =\' 5) e outra apena pela proporção de partículas finas no solo (área basal). Apesar da proporção do terreno ocupada por gramíneas não influenciar nas trajetórias, o controle da mato-competição com herbicida resultou em maiores valores de riqueza de plantas em regeneração. Independentemente das técnicas de plantio e dos tipos de manejo dos projetos de restauração, a estrutura florestal e os processos funcionais dos ecossistemas restaurados tendem a se tornar mais semelhantes aos ecossistemas de referência com o tempo, desde que haja fontes de propágulos e disponibilidade de água e nutrientes no solo. Os resultados obtidos apontam para uma influência muito pequena ou nula das técnicas de plantio e manejo, se comparados com a influência dos fatores ambientais e da paisagem sobre as trajetórias das matas ciliares em restauração. / A remarkable increase in the number of forest restoration projects has been recorded in Brazil in the last decade. As a consequence of this increase, the demand for monitoring and indicators of restoration success has also increased. Despite the advances in restoration ecology, there are still gaps in knowledge about the functioning and self-sustainability of restored ecosystems. In order to fill some of these gaps, in this study we aimed at to answer the following questions: (1) Are there patterns in the attributes of richness, structure, and functional groups on the native riparian Seasonally Semideciduous Forest (SSF), which may be used as goals to forest restoration in this region? (2) What are the variables representing biodiversity, forest structure and functional groups in the restored areas, which follow predictable paths over time? (3) How long it takes for these variables to achieve the reference values of native riparian forests? (4) Among the biotic, abiotic and technical factors analyzed, which can be considered as drivers of the successional trajectories of the restored forests? We assessed four native forests (as references) and 26 restored forests in the SSF region (a sub-type of the Atlantic Forest) in a chronosequence from four to 53 years since planting. At each site, the sample area comprised ten plots of 100 \'M POT.2\' randomly distributed within a range of 50 m away from the margin. We identified and counted all individuals of tree and shrub species from 50 cm in height, planted or regenerating, categorized in three size classes according to diameter at breast height (DBH): DBH < 1 cm, 1 cm \'< ou =\' DBH < 5 cm DBH \'> ou =\' 5 cm. We measured DBH and estimated the height of each individual from the upper class. We categorized the species according to their dispersion syndrome, growth rate, shade tolerance, Nitrogen-fixing ability, degree of threaten, and rarity. For each plot, we measured the canopy openness, and recorded the number of lianas, pteridophytes and number of trees with epiphytes. We also collected composite soil samples for chemical and physical analyses, from each study site. We estimated the aboveground biomass for trees with DBH \'> ou =\' 5 cm, total richness and richness rarefied to 100 individuals. By interviews, field observations, and landscape studies, we obtained information on other ecological factors and management practices that could affect the paths of the restored plant communities. We modeled the trajectory of each variable of the plant community over time, and estimated the period of time required for the restored forests to reach the reference ecosystems. Amongst the analyzed variables, we selected as indicators for monitoring the evolution and sustainability of the restored ecosystem those that were more predictable (best quality models) and that represent the most relevant ecological processes. The attributes that did not change among the native forests and could be used as references were: observed richness, estimated richness for 100 individuals with DBH \'> ou =\' 5 cm, total richness estimated by Jackknife DBH \'> ou =\' 1 cm, density DBH \'> ou =\' 1 cm, basal area, biomass, canopy cover, proportion of shade-tolerant individuals, and proportion of zoochoric species, slow growing, shade tolerant, nitrogen fixers, and rare distribution. Overall, the trajectories were best fitted to the logarithmic models, but richness (DBH \'> ou =\' 5 cm) was better adjusted to the linear model. In the upper size class, richness did not reach the \"species pool\" of the reference ecosystems in the 53 years period analyzed. The trajectories followed similar patterns, regardless of the planting techniques or the number of planted species. Variables representing forest structure were similar among the native forests and quickly recovered in comparison to those related to biodiversity. Thus, the restoration goals can be established based on native forests parameters and such variables would be good indicators even in young restoration plantings. The variables reaching more quickly the reference values were: basal area (12 years), biomass (13 years), average height of the largest trees (26 years), grass cover (33 years), canopy cover (35 years), richness of regenerants with DBH \'> ou =\' 1 cm (52 years), density of regenerants with DBH 1 cm (52 years), and total richness (53 years). The basal area and biomass greatly exceeded the reference values, which may indicate a restrictive filter for the forest dynamics if the density of individuals in the upper class (most planted) does not decrease naturally over time. For some functional groups (zoochoric, N-fixing, rare, and endangered species), the proportions of species and relative densities did not follow predictable trajectories, but some of the restored riparian areas reached and exceeded the reference values. In order to identify the factors driving the paths of the variables selected as indicators, we excluded the age factor, calculating an index of success (the ratio between observed and estimated values for the variable, the first directly measured for each site and the last obtained by the linear models). Among the six variables selected as indicators, some were influenced only by the distance of the source fragment (seedling richness of DBH \'> ou =\' 5 cm) and others only by the proportion of fine particles in the soil (basal area). While the ground cover by grasses does not influence the trajectories, weed control with herbicides resulted in higher plant richness in regeneration. Regardless of planting techniques and management practices, the forest structure and functional processes of restored ecosystems tend to become more similar to reference ecosystems over time, as long as there are propagule sources in the vicinity and availability of soil water and nutrients. Our findings pointed to a weak, if any, effect from the planting techniques or management and a high influence of environmental and landscape factors on the trajectories of a riparian forest restoration.
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Avaliação da funcionalidade ecológica de uma área em processo de restauração no bioma da Mata Atlântica, Rio de Janeiro / Evaluation of the ecological functionality of an area of forest restoration process in the Atlantic Forest, Rio de JaneiroAltivo, Felipe de Souza 16 December 2015 (has links)
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Previous issue date: 2015-12-16 / Não recebi financiamento / The restoration should involve the return of vegetation cover and ecological processes. This study aims to assess whether the restoration of diversity also promoted the recovery of the ecological functionality of an area located in the Atlantic Forest, in Rio de Janeiro. During the study, a set of ecological functionality of indicators based on community diversity, its structure and its context in the landscape were analized. The most efficient indicators for evaluation of the areas were the structure (density, height and basal area), followed by diversity and evenness (H 'and J). Between the 5th and 20th month, there was a significant reduction of diversity, further for families than for the species. However, indicators of ecological functions did not change between the ages despite the reduction in diversity, showing that there was redundancy of functions between different species. The results suggest the deployment of fewer species maintaining the proportion of the functional diversity of species can optimize the actions of forest restoration for promoting the reduction of mortality, therefore generating greater increase in community structure. The regenerating analysis showed the importance of faunal interactions in forest restoration activities, since 77% of regenerating species found in the area have zoochorous dispersion syndrome. / A restauração deve envolver o retorno da cobertura de vegetação e dos processos ecológicos. O presente trabalho visa avaliar se a restauração da diversidade também promoveu a recuperação da funcionalidade ecológica em uma área situada no bioma Mata Atlântica, no Rio de Janeiro. Durante o estudo foi analisado um conjunto de indicadores de funcionalidade ecológica baseados na diversidade da comunidade, sua estrutura e seu contexto na paisagem. Os indicadores mais eficientes para avaliação das áreas foram os de estrutura (densidade, altura e área basal), seguidos dos de diversidade e equitabilidade (H´ e J). Entre 5 e 20 meses de idade, houve redução significativa da diversidade, sendo maior para famílias do que para as espécies. Contudo, os indicadores de funções ecológicas não variaram entre as idades apesar da redução na diversidade, mostrando que houve redundância de funções entre diferentes espécies. A análise dos resultados permite sugerir que a implantação de menor número de espécies mantendo-se a proporção da diversidade funcional das espécies, pode otimizar as ações de restauração florestal por promover a diminuição da mortalidade, consequentemente podendo gerar maior incremento em estrutura da comunidade. A análise de regenerantes evidenciou a importância das interações faunísticas nas ações de restauração florestal, já que 77% das espécies regenerantes encontradas na área possuem síndrome de dispersão zoocórica.
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Relação entre características funcionais e o desempenho de espécies arbóreas nativas em um plantio de restauração / Relationship between functional traits and performance of native tree species in restoration plantingBruno Sano 09 August 2016 (has links)
Em ambientes degradados, a restauração ecológica visa acelerar o processo de sucessão ecológica. A técnica mais utilizada para a restauração de ambientes muito degradados é o plantio de mudas. A seleção das espécies é determinante para o sucesso dos projetos de restauração, pois as espécies precisam se estabelecer e crescer diante das condições do ambiente. Utilizar a abordagem de características funcionais pode ser uma ferramenta promissora para auxiliar a seleção de espécies em projetos de restauração. Em ambientes florestais, há evidências de que as características funcionais afetam o desempenho das espécies, entretanto, existem poucos estudos realizados em áreas em restauração. Neste estudo, foi avaliada a relação entre as características funcionais foliares e a taxa de crescimento relativo em altura e em diâmetro à altura do solo de espécies arbóreas nativas plantadas em uma área degradada que está sendo restaurada. Para descrever a relação entre as características funcionais e a taxa de crescimento relativo (TCR) dos indivíduos foi utilizada a abordagem de seleção de modelos baseados em modelos lineares de efeitos mistos (MLEM). A seleção de modelos foi realizada utilizando o critério de informação de Akaike (Akaike\'s Information Criterion) (AIC). As características funcionais não apresentaram relação com a taxa de crescimento relativo em altura e diâmetro dos indivíduos das espécies, possivelmente devido às diferenças nas condições ambientais entre ambientes florestais e ambientes degradados. Apesar de não ter sido encontrada uma relação entre as características funcionais e a TCR, o modelo mais plausível selecionado indica que indivíduos maiores no início do monitoramento possuem menores taxas de crescimento relativo em altura, ou seja, indivíduos mais altos possuem menores taxas de crescimento em altura. Isso pode ser um indicativo de que as espécies analisadas possuem taxa de crescimento relativo dependente do tamanho. Considerando que não foi encontrada relação entre as características funcionais morfológicas e a taxa de crescimento relativo em uma área em restauração, é razoável supor que essa abordagem não pode ser utilizada em todos os ambientes. Estudos que avaliem características funcionais foliares nos diferentes estágios de desenvolvimento das plantas em ambientes degradados podem refinar essas análises e ajudar a definir se a seleção de espécies para projetos de restauração pode ser feita usando a abordagem de características funcionais / In degraded environments, ecological restoration aims to accelerate the process of ecological succession. The most widely used technique for restoration of degraded environments is the planting of seedlings. The selection of species is crucial to the success of the restoration projects, because the species need to establish and grow under the harsh conditions of the environment. Using the approach of functional traits can be a promising tool to assist in the selection of species in restoration projects. In forest environments, there is evidence that functional traits affect the performance of the species, however, there are few studies conducted in areas undergoing restoration. In this study, the relationship between the functional leaf traits and the relative growth rate in height and in diameter at ground level of native tree species planted in a degraded area that is being restored was evaluated. To describe the relationship between the functional traits and the relative growth rate (RGR) of individuals, we used the approach of model selection based on linear mixed effects models (LMEM). The selection of models was performed using Akaike\'s Information Criterion (AIC). The functional traits showed no relationship with the relative growth rate in height and diameter of the individuals of the species, possibly due to differences in environmental conditions between forest environments and degraded environments. Despite not finding a relationship between the functional traits and the RGR, the most plausible model selected indicates that larger individuals at the beginning of monitoring have lower relative growth rates in height, that is, taller individuals have lower rates of growth in height. Considering that no relationship between the morphological functional traits and the relative growth rate in an area undergoing restoration was found, it is reasonable to assume that this approach cannot be applied in all environments. Studies that assess functional traits of the leaf in the different stages of plant development in degraded environments can refine these analyses and help define whether the selection of species for restoration projects can be accomplished using the approach of functional characteristics
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Caracterização de solos degradados pela atividade agrícola e alterações biológicas após reflorestamentos com diferentes associações de espécies da Mata Atlântica / Characterization of soils degraded by the agricultural activity and biological changes after reforestation with different species associations of the Atlantic ForestLauro Rodrigues Nogueira Junior 15 February 2001 (has links)
No presente estudo perseguimos os seguintes objetivos: a) caracterizar o grau de degradação física e química de solos usados em cultivo agrícola por várias décadas, originalmente cobertos por Mata Atlântica (Floresta Estacional Semidecidual) em Botucatu, SP; b) avaliar as alterações biológicas destes solos ao longo de 16 meses pós-reflorestamento com diferentes modelos de associação de espécies da Mata Atlântica. As áreas experimentais estavam localizadas em duas propriedades (Fazenda Lageado e Edgardia) da Faculdade de Ciências Agronômicas (FCA/UNESP) em Botucatu-SP. O clima da região é do tipo tropical com inverno seco (Cwa, classif. de Köppen). Os solos das áreas experimentais são os seguintes: um Nitossolo Vermelho (NV) de textura argilosa; um Argissolo Vermelho-Amarelo (AVA) álico, de textura areia-franca; e um Latossolo Vermelho-Amarelo (LVA) álico, de textura arenosa. Seis tratamentos (delineamento em blocos casualizados, com três repetições) foram usados: Testemunha; Semeadura Direta; Taungya; Consorciação; Restauração e, por fim, Fragmentos Florestais. Os atributos físicos (textura, densidade e porosidade) foram avaliados nas camadas de 0-10, 10-20 e 20-40cm, os atributos químicos (pH, MO, P, S, K, Ca, Mg, H, Al, CTC, B, Cu, Fe, Mn e Zn) nas camadas de 0-5, 5-10, 10-20 e 20-40cm e os atributos biológicos (C da biomassa microbiana, liberação de CO2 e mineralização de N) nas camadas de 0-5 e 5-20cm. No NV, o teor de argila no solo degradado foi 57% maior do que o obtido no solo sob o Fragmento Florestal (camada 0-10cm), no AVA, 33% maior e, no LVA, 77% menor. Este efeito, no NV e AVA, foi atribuído à remoção de camadas superiores do solo, mais arenosas, pela erosão e exposição das camadas inferiores mais argilosas. No LVA, o menor teor de argila e silte no solo degradado foiatribuído à perda destas frações por eluviação ou em suspensão na enxurrada. O pH, teor de MO, de P e de Ca nos solos NV e LVA foram bem superiores nos Fragmentos Florestais relativamente aos obtidos nas áreas com solos degradados. Diferenças menos acentuadas foram observadas no AVA, como também detectadas para a composição textural, indicando que este solo está menos degradado que os demais. A CTC dos solos mostrou-se altamente correlacionada com os teores de argila e de MO. Isto destaca a importância da preservação da composição granulométrica e elevação dos teores de MO com o intuito de restaurar importantes propriedades físico-químicas do solo, como a CTC. Em áreas com cobertura florestal (Fragmentos Florestais do NV, AVA e LVA), o C da biomassa microbiana apresenta maiores valores na camada superficial e no verão. Fato atribuído a condições mais favoráveis (MO, pH, umidade, temperatura, etc) à manutenção da vida microbiana no solo. O C da biomassa microbiana e, em menor escala, a liberação de CO2 apresentaram-se como bons indicadores das alterações ocorridas após o reflorestamento com as diferentes associações de espécies. No LVA, como o solo desta área se apresenta mais degradado, em relação ao NV e ao AVA, a alta correlação e relação C microbiano/C orgânico indica que a biomassa microbiana é um importante compartimento de reserva do C orgânico do solo. Quanto aos atributos biológicos, as diferenças entre os Fragmentos Florestais e os demais tratamentos continuam a existir nas três áreas e camadas, devendo ser gradativo o retorno desses atributos à condição pré-existente; ademais, o tempo de retorno sofrerá influência das condições edafoclimáticas da área e da associação de espécies presentes. / This study seeks to: a) characterize the degree of physical and chemical degradation of the soils used in agricultural cultivation for several decades, originally covered by the Atlantic Forest (Seasonal Semideciduous Forest) in Botucatu, SP; b) evaluate the biological changes of these soils along a 16-month post-reforestation with different models of species association of the Atlantic Forest. The experimental areas were located in two properties (Fazenda Lageado and Edgardia) of the Agronomic Sciences College (FCA/UNESP) in Botucatu-SP. The climate in that region is the tropical type with dry winter (Cwa, Köppen class.). The soils of the experimental areas are: clayey Red Nitosol (NV), loamy alic Red-Yellow Argisol (AVA), and sandy alic Red-Yellow Latosol (LVA). Six treatments (randomized block design with three replications) were used: Test; Direct Seeding; Taungya; Consortium; Restoration and finally Forestal Fragments. The physical attributes (texture, density and porosity) were evaluated in layers of 0-10, 10-20 and 20-40cm; the chemical attributes (pH, MO, P, S, K, Ca, Mg, H, Al, CTC, B, Cu, Fe, Mn and Zn) in layers of 0-5, 5-10, 10-20 and 20-40cm and the biological attributes (Microbial biomass C, CO2 release and N mineralization) in layers of 0-5 and 5-20cm. The clay content in the degraded soil in NV was 57% higher than that obtained in soil under Forest Fragment (0-10cm layer), 33% higher in AVA, and 77% lower in LVA. This effect in NV and AVA was accredited to the removal of the soil top layers, which are sandier due to the erosion and exposition of the lower layers that are more clayey. In LVA the lowest clay and silt content in the degraded soil was accredited to the loss of these fractions by eluviation or flood suspension. The pH, MO, P and Ca contents in NV and LVA soils were much higher in Forestal iv Fragments regarding those reached in degraded soil areas. The less marking differences were observed in AVA and also detected for the textural composition, thus indicating that this soil is less degraded than the other ones. The CTC of the soils was highly correlated with the clay and MO contents. That highlights the importance of preserving the granulometric composition and elevation of the MO contents in order to restore important physical-chemical soil properties, such as the CTC. In primary forest areas (NV, AVA and LVA Forestal Fragments), the microbial biomass C presents higher values at the top layer and in the summer, a fact accredited to more favorable conditions (MO, pH, moisture, temperature, etc) for the maintenance of the microbial life in the soil. The microbial biomass C and, in a lesser scale, the CO2 release were good indicators of the changes occurred after the reforestation with the different species associations. In the LVA, since the soil of this area is more degraded in relationship to NV and AVA, the high correlation and microbial C/organic C relationship indicate that the microbial biomass is an important reserve compartment of the soil organic C. As to the biological attributes, the differences between the Forestal Fragments and the remaining treatments still exist in the three areas and layers, and the return to the pre-existing attributes is likely to be gradual; moreover, the time of return should undergo influences of the pedoclimatic conditions of the area and of the association of the present species.
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