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The evaluation of various reseeding methods for restoring old croplands in the Highveld region of South AfricaVan Oudtshoorn, Frits 30 November 2007 (has links)
In spite of the relative simple vegetation structure, the Grassland biome has
surprisingly high species diversity. The Grassland biome is also the most
transformed biome in South Africa, with cultivation having the largest impact. When
croplands are abandoned, secondary succession leads to low diversity Hyparrhenia
hirta dominated grassland. A combination of two seed mixtures, two seeding
densities and two establishment methods was established in plots on a recently
abandoned cropland at Suikerbosrand Nature Reserve to evaluate their effect on
secondary succession. The rip plots, where more resources were available between
the rip lines, have shown higher densities of relic weeds as well as local perennials,
showing some progressive successional movement. However, Hyparrhenia hirta was
one of the non-sown perennials increasing in the rip plots. Hyparrhenia invasion and
relic weeds were best controlled in the plough plots. Although Hyparrhenia was
successfully controlled in plough plots, no secondary succession occurred in these
treatments. / Agriculture, Animal Health & Human Ecology / M. Tech. (Nature Conservation)
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Modelling the ecological-economic impacts of restoring natural capital, with a special focus on water and agriculture, at eight sites in South AfricaCrookes, Douglas John 12 1900 (has links)
Thesis (PhD)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: The restoration of natural capital has ecological, hydrological and economic benefits. Are these benefits greater than the costs of restoration when compared across a range of dissimilar sites? This study examines the impact of restoration at eight case study sites distributed throughout South Africa. The benefits of restoration include improved grazing values and crop yields, improvements in water yield and quality, soil carbon improvements, wild products, lumber, fuelwood and electricity. The impact of restoration on all forms of natural capital (i.e. cultivated, replenishable, renewable and non-renewable) is therefore quantified. The costs of restoration include depreciation on capital expenditure, labour costs, equipment and bond refinancing costs. The literature review done during this study presents three frameworks. The first framework classifies social science using the classification scheme of Burrell and Morgan. It shows that system dynamics modelling and neoclassical economics share the same epistemological and ontological characteristics, both of these fall within the naturalistic paradigm, which also characterises most of scientific research. System dynamics modelling and neoclassical economics, however, digress in the Flood and Jackson classification scheme, which is the second framework for classifying social science. Neoclassical economics is characterised by a small number of elements and few interactions between the elements. Systems dynamics modelling, on the other hand, is characterised by a large number of elements and many interactions between the elements. The nature-freedom ground motive is subject to a number of criticisms, including the fact that it introduces dualistic thinking into the analysis, as well as that it does not adequately address normative or moral issues. The framework of Dooyeweerd, the third framework, is presented as a means of transcending the nature-freedom ground motive. Although the nature-freedom ground motive is largely utilised in this study, the analysis does transcend the traditional economic approach in a number of areas. These include, for example, a focus on transdisciplinary methods, disequilibria, adopting a case study approach, and empirical estimation instead of theoretical models. The restoration case studies in this study are examples of individual complex systems. Eight system dynamics models are developed to model interactions between the economic, ecological and hydrological components of each of the case studies. The eight system dynamics models are then used to inform a risk analysis process that culminates in a portfolio mapping exercise. This portfolio mapping exercise is then used to identify the characteristics and features of the different case study sites based on the risk profile of each sites. This study is the first known application of system dynamics, risk analysis and portfolio mapping to an environmental restoration project. This framework could potentially be used by policymakers confronted with budgetary constraints to select and prioritise between competing restoration projects. / AFRIKAANSE OPSOMMING: Die restorasie van natuurlike kapitaal het ekologiese, hidrologiese en ekonomiese voordele. Maar is hierdie voordele groter as die kostes verbonde aan restorasie wanneer dit oor verskeie ongelyksoortige terreine vergelyk word? Hierdie studie bestudeer die impak van restorasie op agt verskillende studie terreine versprei regoor Suid-Afrika. Die voordele van restorasie sluit die volgende in: beter weiding waardes en oes opbrengste, verbeterde water lewering en water kwaliteit, verbetering van grondkoolstof, wilde produkte, hout, brandstofhout en elektrisiteit. Die impak van restorasie op alle vorme van natuurlike kapitaal (gekultiveerd, aanvulbaar, hernubaar en nie-hernubaar) is daarom gekwantifiseer. Die kostes van restorasie sluit in ‘n vermindering in kapitaal uitgawes, arbeidskoste, toerusting en verband herfinansieringskoste. Die literatuurstudie hou drie raamwerke voor. Die eerste raamwerk klassifiseer sosiale wetenskappe volgens die Burrel en Morgan klassifikasie skema. Dit wys daarop dat dinamiese stelsel modellering en neoklassieke ekonomie dieselfde epistemologiese en ontologiese eienskappe deel; beide val binne die naturalistiese paradigma, wat dan ook meeste wetenskaplike navorsing tipeer. Stelseldinamiese modellering en neoklassieke ekonomie wyk egter af na die Flood and Jackson klassifikasie skema, wat die tweede raamwerk is waarvolgens sosiale wetenskappe geklassifiseer word. Neoklassieke ekonomie word gekenmerk aan 'n klein aantal elemente en 'n beperkte hoeveelheid interaksie. Stelseldinamiese modellering het egter 'n groot aantal elemente met veel meer interaksies tussen hierdie elemente. Die natuur-vryheid grondmotief is onderworpe aan 'n aantal punte van kritiek, insluitende die feit dat dit dualistiese denke in analise inbring. Verder spreek dit ook nie voldoende die normatiewe of morele kwessies aan nie. Die raamwerk van Dooyeweerd, wat dan die derde raamwerk is, word voorgestel as 'n wyse waarop die natuur-vryheid grond-motief getransendeer kan word. Alhoewel die natuur-vryheid grondmotief grootliks gebruik word in hierdie studie, transendeer die analise die tradisionele ekonomiese benadering op 'n aantal gebiede. Hierdie gebiede sluit die volgende in: 'n fokus op transdissiplinere metodes, onewewigtigheid, 'n gevallestudie benadering, en empiriese skatting in plaas van teoretiese modelle. Die restorasie gevallestudies wat in hierdie studie gebruik word is voorbeelde van individuele komplekse sisteme. Agt dinamiese stelsel modelle word ontwikkel om die interaksies tussen ekonomiese, ekologiese en hidrologiese komponente in elke gevallestudie te modelleer. Hierdie agt stelseldinamiese modelle word dan gebruik in 'n risiko analise proses wat uitloop op 'n portefeulje plot oefening. Hierdie portefeulje plot oefening word dan gebruik om eienskappe en kenmerke van verskeie gevallestudie terreine te identifiseer gebaseer op die risiko profiel van elke terrein. Hierdie studie is die eerste bekende toepassing van dinamiese stesels, risiko analise en portefeulje plot tot 'n omgewingsrestorasie projek. Hierdie raamwerk kan potensieël gebruik word deur beleidskrywers wat met begrotings beperkinge gekonfronteer word om tussen restorasie projekte te kies en om hulle te prioritiriseer.
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Rehabilitation as a method of understanding vegetation change in Paulshoek, Namaqualand.Simons, Liora-lee January 2005 (has links)
The main aim of this study was to test rehabilitation interventions in a system altered by heavy grazing, and to develop methods of monitoring these interventions.
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De la mise en évidence à la gestion de l’effet de cerf : Leçons pratiques et théoriques fournies par l’introduction du cerf à queue-noire sur Haïda Gwaii / From research to management of deer impacts : Practical and theoretical lessons learned from the introduction of black-tailed deer to Haida GwaiiChollet, Simon 05 December 2012 (has links)
Depuis le début du 20ième siècle, les changements d'usage des terres, la disparition des prédateurs et les régulations de la chasse ont provoqué une augmentation des populations de cervidés dans les forêts tempérés et boréales. Ce phénomène, qui est un grand succès de la conservation de ces espèces, a toutefois conduit à des surabondances qui ont entrainé des effets négatifs en cascades sur la végétation et les communautés animales qui en dépendent.J'ai utilisé l'expérience naturelle qu'est l'introduction du cerf à queue noire sur l'archipel d'Haïda Gwaii pour étudier les conséquences de sa surabondance sur un écosystème tempéré peu perturbé par les activités anthropiques. J'ai ainsi pu mettre en évidence les contrôles descendants directs et indirects qu'exerce l'herbivore sur les Bryophytes (positifs), les plantes vasculaires (négatifs) et sur l'avifaune (négatifs) quand il n'est pas limité par les prédateurs ou la chasse.J'ai complété ces résultats par une analyse régionale sur 20 ans pour montrer que la perte de biodiversité enclenchée par la surabondance de ces cerfs était un phénomène d'érosion continu se prolongeant bien au-delà de l'impact initial. A l'échelle de l'Amérique du Nord, j'ai ensuite pu montrer, conformément aux prédictions faite à partir des études locales, qu'il existait une relation entre surabondance des populations d'ongulés et déclin de l'avifaune du sous-bois du continent. Enfin, j'ai analysé les suivis d'une expérience de réduction des densités de cerfs entamée sur deux îles il y a 13 ans. La végétation et l'avifaune se sont partiellement reconstituées démontrant qu'il est possible (1) de restaurer les réseaux trophiques fortement modifiés et (2) qu'une telle restauration si elle est possible prendra du temps et ne convergera pas (rapidement) vers un état initial. Afin de limiter les conséquences dommageables provoquées par la surabondance des cervidés, la conservation des prédateurs et l'augmentation de la chasse doivent être favorisés. / Since the past century land use changes, elimination of predators and hunting regulations triggered an increase of deer populations in temperate and boreal forests. This remarkable conservation success, lead to deer overabundance and to a cascade of negative effects on vegetation and on animal communities depending on it. I used the natural experiment provided by the introduction of black-tailed deer to Haida Gwaii to analyze the consequences of overabundant herbivore populations on temperate ecosystem only slightly modified by human activities. This unique situation allowed me to demonstrate the direct and indirect top-down effects that herbivores uncontrolled by predation or hunting exert on Bryophytes (positive) and Vascular plants (negative) as well as on songbirds (negative).I used an analysis of regional trends spanning over 20 years to show that biodiversity erosion caused by overabundant deer extends far beyond the initial impact. At the North-American scale I was able to establish a relationship between expanding deer populations and continent wide declines in understory birds. Finally I analyzed the results of an experimental reduction in deer populations initiated 13 years ago on two islands. The understory plants and songbirds responded positively and we show that (1) it is possible to restore trophic networks even after their dramatically modification, (2) that such a restoration while possible takes time and does not (rapidly) converge towards an identified initial state. From a practical standpoint I recommend that to mitigate negative effects of overabundant deer, predator conservation and hunting have to be promoted.
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Estudos genéticos de jatobá (Hymenaea courbaril L.) em área natural e restauração florestal com espécies nativas / Hymenaea courbaril L. (jatobá): genetic studies in natural population and forest restoration areas with native speciesPereira, Lya Carolina da Silva Mariano 09 October 2017 (has links)
O bioma Mata Atlântica tem sofrido com a fragmentação florestal e como forma de reestabelecer ambientes florestais são realizados plantios de restauração. Porém, por muito tempo houve preocupação somente com a composição florística das áreas e a diversidade genética foi negligenciada. Além disso, muitas áreas são implantadas a partir de sementes coletadas em áreas florestais geralmente pouco conservadas, pequenas e isoladas, o que pode comprometer a qualidade genética das mudas, produzindo indivíduos menos adaptados em decorrência da depressão endogâmica. Assim este trabalho teve como objetivo principal analisar o aspecto genético em áreas de restauração na região do Pontal do Paranapanema e área natural de referência, o Parque Estadual Morro do Diabo (PEMD), utilizando o jatobá (Hymenaea courbaril L.) como espécie modelo. No capítulo 1 com o objetivo de verificar a diversidade genética de H. courbaril em áreas de restauração florestal, foram selecionadas duas áreas de plantio com espécies nativas. Nestas áreas e no PEMD foram coletadas amostras foliares de indivíduos adultos que foram genotipadas para oito locos microssatélites. No PEMD ainda foram coletados frutos em 12 matrizes para caracterização do sistema reprodutivo. As três áreas estudadas apresentaram diversidade genética e níveis de endogamia similares. Nas três áreas de estudo foi identificada baixa estruturação genética espacial. Houve predomínio de fecundação cruzada para a produção de frutos na área natural, porém a taxa de cruzamentos entre indivíduos aparentados foi até dez vezes maior que a observada em outras populações da espécie. No capítulo 2 com o objetivo de verificar se há depressão endogâmica em progênies provenientes do PEMD foram selecionadas 320 sementes de 12 matrizes. Estas e seus frutos foram medidos. As plântulas a que deram origem também foram mensuradas, mensalmente, durante 15 meses. Todos os indivíduos foram genotipadas para oito locos microssatélites. A coancestria, foi estimada e os indivíduos separados em: não aparentados (tu), aparentados (tr) e autofecundação (s). Foi verificada diferença entre as métricas das plantas de acordo com o nível de coancestria entre indivíduos. Também foram estimados os valores de depressão endogâmica (ID). A quantidade de indivíduos irmãos de autofecundação foi muito pequena, sendo a maioria proveniente de cruzamento entre indivíduos não aparentados. A depressão endogâmica por autofecundação foi mais evidente no peso e tamanho dos frutos, e amena ou inexistente para os demais caracteres. Isto provavelmente por estas sementes terem sido coletadas em um fragmento grande e bem conservado e que ainda não sofre as consequências da depressão endogâmica. Assim, nosso trabalho mostrou que áreas de restauração florestal que seguiram as recomendações genéticas de implantação, apresentam diversidade genética suficiente para H. courbaril, podendo estas áreas serem fonte de coleta de sementes no futuro. E que os indivíduos provenientes de sementes do PEMD não apresentaram efeito de depressão endogâmica até 15 meses de desenvolvimento em viveiro. / The Brazilian Atlantic Forest was severely deforested and restoration initiatives are necessary to reestablish environments. However, for a long time there is only concern over floristic composition and the genetic diversity has been neglected. In addition, several restoration areas are planted from seeds collected in forest areas that are generally poorly preserved, small and isolated, which may compromise the genetic quality of the seedlings, producing less adapted individuals due to inbreeding depression. The aim of this work was to analyze the genetic aspects of Hymenaea courbaril L. in restoration areas in Pontal do Paranapanema region, and a natural reference forest, the Morro do Diabo State Park (PEMD), where seeds were also collected. In Chapter 1, to verify the genetic diversity of H. courbaril in areas of forest restoration, using eight microsatellites, two restoration areas were selected. In these areas and in the PEMD, leaf samples from adult individuals were collected. In the PEMD, fruits were collected in 12 seed trees for mating system characterization. The three areas presented similar genetic diversity and levels of inbreeding. Low spatial genetic structure was identified in the three studied areas. In the natural forest, fruits were mainly produced through outcrossings, but the rate of mating among relatives was up to ten times higher than the observed in other H. courbaril populations. In Chapter 2, to verify the inbreeding depression in the PEMD were selected 320 seeds from eight seed trees. The seeeds and their fruits were measured. The seedlings were also measured monthly, during 15 months. All seedlings were genotyped with eight microsatellite loci. From the pairwise coancestry the seedlings were separated into three categories: outcrossing among unrelated individuals (tu), outcrossing among related individuals (tr), and selfing (s). We verified differences among groups in the metrics of seedlings according to the level of coancestry among individuals. The values of inbreeding depression (ID) were also estimated. The number of selfed seedlings were very small, and the majority were from outcrossing among unrelated individuals. Inbreeding depression by selfing was more evident in weight and size fruit, and was insignificant or non-existent for other characters. This is probably because these seeds were collected in a large and preserved forest fragment, that does not suffer the consequences of inbreeding depression yet. Thus, our work showed that forest restoration areas that followed the genetic recommendations present enough genetic diversity for H. courbaril, and these areas may be a source of seeds for collection in the future. Besides that, seedlings from seed trees in PEMD did not present inbreeding depression effect up to 15 months of nursery development.
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Tamanhos de recipientes e o uso de hidrogel no estabelecimento de mudas de espécies florestais nativas / Sizes of containers and the use of hydrogel in the establishment of native forest species seedlingsBarbosa, Tiago Cavalheiro 14 September 2011 (has links)
A demanda por projetos de restauração ecológica, com a utilização de técnicas de plantio total, tem aumentado nos últimos anos, com a consequente necessidade de otimização dos insumos para tal atividade que, além de garantir maior sobrevivência das mudas a campo, é essencial para o setor. Assim, as compensações ambientais, geradas pela obra do trecho sul do Rodoanel Mário Covas (São Paulo), proporcionaram uma importante oportunidade de se realizar alguns estudos nessa temática. O objetivo deste trabalho foi avaliar a taxa de sobrevivência e o crescimento inicial (12 meses), de 30 espécies arbóreas nativas, provenientes de mudas acondicionadas em recipientes com 3 volumes distintos (tubetão 290 cm3, tubetinho 56 cm3 e bandeja 9 cm3), com e sem utilização de hidrogel no plantio, e submetidas às mesmas ações de manutenção. As espécies nativas regionais contemplaram todos os grupos sucessionais (pioneira e não pioneiras), pertencentes a 17 famílias botânicas. Como resultados deste trabalho, pode-se concluir que as espécies provenientes do recipiente tubetão obtiveram as menores porcentagens de mortalidade, seguidas de tubetinho e bandeja, entretanto algumas espécies de bandeja mostraram-se com índices de mortalidade menores, se comparadas a outras espécies provenientes de tubetinhos, apresentando assim possibilidades de uso, desde que adotados manejos diferenciados (irrigação pós-plantio e controle de competidores) visando a garantir o aumento da sobrevivência inicial das mudas. O hidrogel não interferiu no estabelecimento e nem no crescimento das mudas nos diferentes recipientes, para o período em que o experimento foi avaliado. Quanto ao desenvolvimento das mudas em crescimento e incremento de altura, pode-se concluir que, uma vez garantido o estabelecimento das mudas, não houve diferenças entre os recipientes, reforçando que, com manejos diferenciados, os custos da restauração poderão ser significativamente reduzidos, para as situações que exijam como metodologia o plantio total na restauração ecológica de uma dada área. / The demand for ecological restorations project, using total planting techniques, has increased in recent years, with the consequent optimizations need of inputs for such activity that, besides increasing the seedlings survival in the field, is essential for the sector. Thus, environmental compensation, generated by the work of the southern section of the Rodoanel Mário Covas (São. Paulo), provided a valuable opportunity to conduct some studies in this area. This studys aim was to evaluate the survival rate and early growth (12 months) of 30 native species from plants in containers packed with three separate volumes (290 cm3 tubetão, tubetinho 56 cm3 and bandeja 9 cm3), with and without hydrogels use at planting, and subordinated to the same maintenance actions. The regional native species, contemplated at all successional groups (pioneer and non-pioneer), belonging to 17 botany families. As a result of this work, we can conclude that species from the container tubetão had the lowest percentage of mortality, followed by tubetinho and bandeja, however some bandeja species have come out with lower mortality rates, compared to other species from tubetinhos, thus presenting use opportunities since different management are adopted (irrigation after planting and control of competitors) in order to guarantee the increase of initial survival of seedlings. The hydrogel did not affect the establishment and neither the growth of seedlings in different containers, during the period in which the experiment was evaluated. Concerning the seedlings development in growth and increase in height, one can conclude that once guaranteed the seedlings establishment of, there were no differences between the containers, reinforcing that with different managements, the restoration costs may be significantly reduced for situations that require the total planting as a methodology in ecological restoration of a given area.
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Enriquecimento de uma floresta em restauração por meio da semeadura direta e introdução de plântulas / Enrichment of a forest undergoing restoration through direct seeding and inroduction of small seedlingsNahssen, Maria Helena Cury 05 November 2018 (has links)
O enriquecimento assistido é uma alternativa possível para se aumentar as chances de autoperpetuação de florestas em processo de restauração ecológica que foram implantadas por meio de uma combinação inadequada de espécies, inseridas em matrizes pouco permeáveis à fauna e à flora e que passaram por um intenso histórico de perturbação. No entanto, técnicas de baixo custo para o enriquecimento de áreas em restauração ainda são pouco estudadas, havendo demanda de pesquisas para as diferentes fitofisionomias florestais e espécies nativas pertencentes aos grupos sucessionais. Neste contexto, o presente trabalho visa avaliar a viabilidade e a eficiência da semeadura direta e da introdução de plântulas de espécies arbóreas de diversidade para o enriquecimento de uma área em processo de restauração a 14 anos, situada na fitofisionomia Floresta Estacional Semidecidual, município de Mogi-Guaçu-SP. Foram utilizadas sementes e plântulas de sete espécies arbóreas (cinco secundárias iniciais - Centrolobium tomentosum Guillem. ex Benth.; Chrysophyllum gonocarpum (Mart e Eicheler). Engl; Lafoensia pacari Saint-Hilaire; Astronium graveolens Jacq.; Pterogyne nitens Tul. e duas clímaces - Hymenaea courbaril L.; Eugenia involucrata DC.) que foram introduzidas em áreas com diferentes níveis de luz (borda e interior da floresta). A técnica de introdução de plântulas resultou em uma taxa de estabelecimento após um ano mais elevada (25,71%) do que a semeadura direta (8,61%). Os indivíduos da maior parte das espécies tiveram pequeno incremento em altura ao longo de um ano. A linha de enriquecimento situada no interior da área em restauração apresentou maior densidade em comparação às linhas da borda para ambas as técnicas. Contudo, as repostas variaram entre as espécies, sugerindo que a introdução de propágulos em diversos microssítios pode ser a alternativa mais adequada. A emergência das plântulas foi positivamente relacionada ao peso da semente, isto é, as espécies com sementes mais pesadas tiveram um maior número de plântulas emergentes do que as espécies com sementes de peso intermediário e mais leves. A semeadura direta apresentou melhor custo-efetividade do que a introdução de plântulas pois, mesmo precisando de uma maior densidade de propágulos para se obter o número desejado de indivíduos estabelecidos, seus custos ainda são inferiores. No entanto, ainda faltam sementes em quantidade e de qualidade no mercado, assim como conhecimentos acerca do desempenho das espécies utilizando ambas as técnicas testadas. Concluiu-se que tanto a semeadura direta, quanto a introdução de plântulas se mostraram técnicas viáveis para o enriquecimento inicial de uma área em restauração, mas a efetividade ecológica e econômica das mesmas pode ser melhorada por meio de introduções dos propágulos em diferentes períodos da estação chuvosa e pelo aumento da densidade de propágulos a serem introduzidos em campo, desde que ainda seja vantajoso economicamente. Futuros estudos também poderiam explorar diferentes ações que garantam a sobrevivência das plântulas após o plantio, como aclimatação das plântulas antes da introdução em campo e adubações adequadas para a formação de um torrão bem agregado. / Assisted enrichment is a possible alternative to increase the chances of self-perpetuation of forests undergoing restoration implemented through an inadequate combination of species. It takes place specially in restoration sites inserted in matrices that are not permeable to fauna and flora and a long land-use history. However, low cost techniques for the enrichment of areas under restoration are still little studied, and there is a demand for research on different types of forest and native species belonging to different ecological groups. In this context, the present study evaluated the viability and efficiency of direct seeding and introduction of small seedlings of seven species for the enrichment of a 14-year-old restoration area, located in the municipality of Mogi-Guaçu, SP, Brazil, inside the Atlantic Forest, specifically in the Seasonal Semidecidual Forest type. Seeds and seedlings of seven tree species (five early secondary - Centrolobium tomentosum Guillem. Ex Benth.; Chrysophyllum gonocarpum (Mart and Eicheler), Engl. Lafoensia pacari Saint-Hilaire; Astronium graveolens Jacq., Pterogyne nitens Tul.; and two climax - Hymenaea courbaril L., Eugenia involucrata DC.) were introduced in areas with different levels of light (edge and interior of the area under restoration). Establishment rates after one year were higher for seedling introduction technique (25.71%) than direct seeding (8.61%). The individuals of most species had small increases in height over a year. The enrichment line located inside the restoration area presented higher density in comparison to the edge lines for both techniques. However, the responses varied among the species, suggesting that the introduction of propagules in several microsites may be the most adequate alternative. Emergence was positively related to seed weight. Direct seeding was more cost-effective than seedling introduction because, even though it requires a higher density of seedlings to obtain the desired number of established individuals, its costs are still lower. However, there is still a lack of quality and quantity seed in the market, as well as knowledge about the performance of the species using both techniques tested. Therefore, both direct seeding and small seedling introduction were feasible techniques for the initial enrichment of an area undergoing restoration, but the ecological and economic effectiveness of the techniques can be improved through introductions of propagules at different periods of the rainy season and by increasing the density of propagules to be introduced in the field, as long as it is still economically advantageous. Future studies could also explore ways to ensure seedling survival after planting, such as acclimatization of seedlings before field introduction and adequate fertilization for the formation of a well-aggregated clod.
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A habitat suitability model for wading birds in a large subtropical lake: linking hydrologic fluctuations and nestingUnknown Date (has links)
Anthropogenic hydrologic alterations can affect the quality of lake littoral zone
habitats for wading birds, such as the great egret (Ardea alba), snowy egret (Egretta
thula), and white ibis (Eudocimus albus). One such lake in Florida, Lake Okeechobee,
has experienced a marked decline in wading bird nesting since the 1970’s, concomitant
with changes in lake level management. It’s hypothesized that a reduction in foraging
habitat has led to the nesting decline; however, there is little quantitative evidence of this
link. A habitat suitability model was developed for Lake Okeechobee wading birds that
incorporate the spatial and temporal dynamics of environmental factors that affect
wading bird foraging and tests whether foraging habitat is linked to numbers of nests. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2014. / FAU Electronic Theses and Dissertations Collection
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Tamanhos de recipientes e o uso de hidrogel no estabelecimento de mudas de espécies florestais nativas / Sizes of containers and the use of hydrogel in the establishment of native forest species seedlingsTiago Cavalheiro Barbosa 14 September 2011 (has links)
A demanda por projetos de restauração ecológica, com a utilização de técnicas de plantio total, tem aumentado nos últimos anos, com a consequente necessidade de otimização dos insumos para tal atividade que, além de garantir maior sobrevivência das mudas a campo, é essencial para o setor. Assim, as compensações ambientais, geradas pela obra do trecho sul do Rodoanel Mário Covas (São Paulo), proporcionaram uma importante oportunidade de se realizar alguns estudos nessa temática. O objetivo deste trabalho foi avaliar a taxa de sobrevivência e o crescimento inicial (12 meses), de 30 espécies arbóreas nativas, provenientes de mudas acondicionadas em recipientes com 3 volumes distintos (tubetão 290 cm3, tubetinho 56 cm3 e bandeja 9 cm3), com e sem utilização de hidrogel no plantio, e submetidas às mesmas ações de manutenção. As espécies nativas regionais contemplaram todos os grupos sucessionais (pioneira e não pioneiras), pertencentes a 17 famílias botânicas. Como resultados deste trabalho, pode-se concluir que as espécies provenientes do recipiente tubetão obtiveram as menores porcentagens de mortalidade, seguidas de tubetinho e bandeja, entretanto algumas espécies de bandeja mostraram-se com índices de mortalidade menores, se comparadas a outras espécies provenientes de tubetinhos, apresentando assim possibilidades de uso, desde que adotados manejos diferenciados (irrigação pós-plantio e controle de competidores) visando a garantir o aumento da sobrevivência inicial das mudas. O hidrogel não interferiu no estabelecimento e nem no crescimento das mudas nos diferentes recipientes, para o período em que o experimento foi avaliado. Quanto ao desenvolvimento das mudas em crescimento e incremento de altura, pode-se concluir que, uma vez garantido o estabelecimento das mudas, não houve diferenças entre os recipientes, reforçando que, com manejos diferenciados, os custos da restauração poderão ser significativamente reduzidos, para as situações que exijam como metodologia o plantio total na restauração ecológica de uma dada área. / The demand for ecological restorations project, using total planting techniques, has increased in recent years, with the consequent optimizations need of inputs for such activity that, besides increasing the seedlings survival in the field, is essential for the sector. Thus, environmental compensation, generated by the work of the southern section of the Rodoanel Mário Covas (São. Paulo), provided a valuable opportunity to conduct some studies in this area. This studys aim was to evaluate the survival rate and early growth (12 months) of 30 native species from plants in containers packed with three separate volumes (290 cm3 tubetão, tubetinho 56 cm3 and bandeja 9 cm3), with and without hydrogels use at planting, and subordinated to the same maintenance actions. The regional native species, contemplated at all successional groups (pioneer and non-pioneer), belonging to 17 botany families. As a result of this work, we can conclude that species from the container tubetão had the lowest percentage of mortality, followed by tubetinho and bandeja, however some bandeja species have come out with lower mortality rates, compared to other species from tubetinhos, thus presenting use opportunities since different management are adopted (irrigation after planting and control of competitors) in order to guarantee the increase of initial survival of seedlings. The hydrogel did not affect the establishment and neither the growth of seedlings in different containers, during the period in which the experiment was evaluated. Concerning the seedlings development in growth and increase in height, one can conclude that once guaranteed the seedlings establishment of, there were no differences between the containers, reinforcing that with different managements, the restoration costs may be significantly reduced for situations that require the total planting as a methodology in ecological restoration of a given area.
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Transplante de epífitas entre Florestas Estacionais Semideciduais para enriquecimento de florestas em processo de restauração / Enrichment of forests in process of restoration through epiphytes transplantation, in Semideciduous Seasonal ForestDuarte, Marina Melo 06 March 2013 (has links)
O enriquecimento com diferentes formas de vida, como com epífitas, é fundamental para o desenvolvimento de florestas em restauração, em paisagens fragmentadas, onde a dispersão natural é limitada. Epífitas são plantas que crescem sobre outras (forófitos). Têm papel ecológico importante, realizando ciclagem de nutrientes e oferecendo microambientes e alimentos a outras formas de vida. Características de forófitos, clima e microclima influenciam populações locais de epífitas. Para aumentar o sucesso do enriquecimento em florestas em restauração, é importante determinar quais filtros podem atuar no processo. Fizemos o censo de áreas que receberam autorização para supressão vegetal e obtivemos que, a cada ano, cerca de 500 ha de Florestas Estacional Semidecidual e Ombrófila Densa, em diferentes estágios de regeneração, são desmatados, apenas no estado de São Paulo. Elas podem fornecer material que pode ser recuperado e empregado na restauração de outras florestas. Neste trabalho, damos enfoque às epífitas que podem ser disponibilizadas a partir desse desmatamento. Transferimos 360 indivíduos de seis espécies delas, entre Bromeliaceae (Aechmea bromeliifolia e Tillandsia pohliana), Orchidaceae (Catasetum fimbriatum e Rodriguezia decora) e Cactaceae (Lepismium cruciforme e Rhipsalis floccosa) para duas Florestas Estacionais Semideciduais em processo de restauração, uma com 13 anos e outra com 23. As médias anuais de cobertura de dossel, entre os forófitos escolhidos, variaram entre 62,2 e 85,0% na floresta de 13 anos e entre 79,3 e 92,9% na floresta de 23 anos. Taxas de sobrevivência das diferentes espécies de epífitas foram superiores em floresta mais jovem, variando de 63.33 a 100%, enquanto em floresta mais madura variaram entre 55,17 e 89,66%. Transplantes usando fibra de palmeiras, capaz de reter água, e realizados no início de estação chuvosa podem ter explicado o maior sucesso em floresta mais nova. Taxas de sobrevivência, fixação, ramificação, floração e frutificação não estiveram relacionadas à espécie de forófito, à rugosidade de casca ou à posição de transplante. Por outro lado, elas estiveram relacionadas às espécies das próprias epífitas. Apenas em algumas situações e para determinadas espécies, taxas de fixação, ramificação e reprodução sexuada estiveram relacionadas aos valores de cobertura de dossel. Animais podem ter importantes papéis como polinizadores e dispersores de epífitas, o que mostra que sua presença na floresta é fundamental para a permanência dessas plantas em longo prazo. Ao final, separamos as principais conclusões tiradas deste trabalho e fizemos um guia de procedimentos práticos a serem adotados no enriquecimento de florestas em restauração usando epífitas provenientes de florestas a serem suprimidas. / Enrichment using non-arboreal life forms, such as epiphytes, is critical to the development of forests under restoration, in fragmented landscapes, where natural dispersal is scarce. Epiphytes are plants that grow on top of other plants (phorophytes). They play very important ecological role, performing nutrient cycling and providing microenvironments and food to other life forms. Features of phorophytes, climate, and microclimate influence local diversity of epiphytes. In order to improve success of enrichment in areas under restoration, it is important to determine what filters may play a role in this process. We censused areas that received authorization for vegetation removal and found out that, every year, about 500 ha of Semideciduous Seasonal Forests and Rainforests, in different regeneration stages, are legally cut down, only in the state of Sao Paulo. They can provide material that can be recovered and used to restore other forests. In this work, we focused on the epiphytes that may become available from deforestation. We transferred 360 individuals of six species of this life form among Bromeliaceae (Aechmea bromeliifolia and Tillandsia pohliana), Orchidaceae (Catasetum fimbriatum and Rodriguezia decora) and Cactaceae (Lepismium cruciforme and Rhipsalis floccosa) to two different Semidecidual Seasonal Forests in process of restoration, one of them was 13 years old and the other, 23 years old. Annual canopy cover averages provided by diffferent phorophytes ranged from 62.2 to 85.0% in 13-year old forest and from 79.3 to 92.9% in 23-year-old forest. Survival rates of epiphytes species were higher in the younger forest, from 63.33 to 100%, compared to the ones obtained in the more mature forest, from 55.17 to 89.66%. Transplants performance using palm tree fiber, which enables higher water retention, and at the beginning of rainy season may have been responsible for higher survival rates in the young forest. Survival, rooting, sprouting, flowering and fruiting rates were not related to phorophyte species, to their bark roughness nor to the position of transplantation. On the other hand, they were always relatated to epiphyte species. Only in some cases and for determined species, rooting, sprouting, flowering and fruiting were related to canopy cover. Animals can play important roles as pollinators and dispersers of epiphytes, which shows that their presence in forests is fundamental for the long-term persistance of these plants. In the end, we gathered the main results taken from this work and organized a guide of practical procedures to be adopted in enrichment of areas using epiphytes from forests about to be suppressed.
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