Dissertations / Theses on the topic 'Nature conservation – Florida'

Key Largo woodrats are an endangered subspecies with an extremely limited habitat. This study sought to understand woodrat habitat preferences in order to guide management. Woodrats build stick nests from natural and artificial materials, so nest distribution and nest occupancy were used as indicators of preference. Distribution was determined by nest surveys, and remote cameras were used to assess occupancy. Forest structure, human disturbance, nest, and animal presence metrics were also collected. More nests were found along abandoned roads than along forest transects and more artificial nests were occupied than natural nests. These findings indicate that woodrats prefer areas with human disturbance, rather than forest age and structure as previously believed. This may have consequences on woodrat management, as it suggests that man-made materials are currently needed by woodrats even in a protected natural area.

There are two biomes in the state of Rio Grande do Sul - the Atlantic Forest and the Pampa. According to official agencies, they represent the smallest native vegetation coverages left in Brazil, and only about 2.6% of this territory is protected in Conservation Units (CUs).Thus, we see the importance of the implementation of CUs in these areas of the state, as well as the need for knowledge of the flora, in order to provide effective measures to preserve not only species, but of the whole ecosystem. This study aimed to carry out the floristic survey (native vascular plants) of a fragment located in a biome area of Atlantic Forest, in the forest edge of the Serra Geral, in the MO Ã Private Reserve of the State Natural Heritage, located in the municipality of Itaara, Rio Grande do Sul, Brazil.To do so, in the period between 2014 and 2015, fifteen collecting expeditions took place in the study area, by the Caminhamento method, covering the sixteen seasons. The collected material was identified, herborized and forwarded for inclusion in the SMDB herbarium. In total, there were 277 native taxa from Brazil, belonging to 72 families. Among the Angiosperms, the highest number of species was distributed in the Asteraceae, Poaceae and Fabaceae families; among the Ferns, the highest number was from the Polypodiaceae, Pteridaceae and Dryopteridaceae families. The group of Gymnosperms was represented by the Araucaria angustifolia (Bertol.)Kuntze and Podocarpus lambertii Klotzsch ex Endl. This study provided a table including the families and species with their habit, illustrations, and information on the occurrence of species in the different environments of the area that was studied, as well as their degree of threat in Rio Grande do Sul. The results extend the knowledge of the local flora and of the edge Plateau of Rio Grande do Sul in Itaara, also demonstrating the importance and potential of the studied site.
O estado do Rio Grande do Sul está contemplado por dois biomas, a Mata Atlântica e o Pampa, os quais, segundo órgãos oficiais, estão entre as menores coberturas remanescentes vegetais nativos no Brasil e apenas cerca de 2,6% do seu território estão protegidos em Unidades de Conservação (UCs). Com isso, percebe-se a importância da implementação de UCs nessas áreas do Estado, bem como a necessidade do conhecimento da flora a fim de propiciar ações efetivas para a preservação não só das espécies, mas de todo ecossistema. Neste trabalho, teve-se por objetivo realizar o levantamento florístico (plantas vasculares nativas), de fragmento localizado em área do bioma Mata Atlântica, em região de floresta no rebordo da Serra Geral, na Reserva Particular do Patrimônio Natural Estadual MO Ã, localizada no município de Itaara, Rio Grande do Sul, Brasil. Para isso, no período entre 2014 e 2015, foram realizadas dezesseis expedições de coleta na área estudada, por meio do método de caminhamento, abrangendo as quatro estações do ano. O material coletado foi identificado, herborizado e encaminhado para inclusão no herbário SMDB. No total, foram registrados 277 táxons nativos do Brasil, pertencentes a 72 famílias. Entre as Angiospermas, o maior número de espécies ficou distribuído nas famílias Asteraceae, Poaceae e Fabaceae; entre as Samambaias, nas famílias Polypodiaceae, Pteridaceae, Dryopteridaceae. O grupo das Gimnospermas ficou representado por Araucaria angustifolia (Bertol.) Kuntze e Podocarpus lambertii Klotzsch ex Endl. Neste trabalho também é fornecida uma tabela com as famílias e espécies com respectivo hábito, fotografias, além de informações relacionadas à ocorrência das espécies nos diferentes ambientes da área estudada e ao grau de ameaça das mesmas. Os resultados obtidos ampliam o conhecimento sobre a flora local, bem como da região do rebordo do Planalto Meridional, demonstrando também a importância e o potencial do local estudado.

Coastal forest retreat in the Florida Keys during the 20th century has been attributed to a combination of sea level rise and hurricane storm surge impacts, but the interactions between these two disturbances leading to forest decline are not well understood. The goal of my research was to assess their effects over a period spanning more than two decades, and to examine the relationships between these press and pulse disturbances and freshwater availability in pine rockland, hardwood hammock, and supratidal scrub communities. Impacts and recovery from two storm surges, Hurricanes Georges (1998) and Wilma (2005), were assessed with satellite-derived vegetation indices and multiple change detection techniques. Impacts were greater at lower elevations, and in hardwood hammock, spectral signatures indicative of plant stress and productivity returned to pre-disturbance levels within a few years. In pine rockland, impacts were predominately related to Hurricane Wilma, however, a similar return to pre-disturbance conditions was absent, suggesting that trajectories of disturbance recovery differed between the two communities. Long-term monitoring of forest composition, structure, and groundwater salinity showed that compositional shifts in the low shrub stratum were associated with salinization of the freshwater resource attributable to sea level rise. Throughout the course of twelve months of climate and groundwater monitoring (2011-2012), groundwater salinity generally decreased in response to large precipitation events. Modeling of geophysical data indicated that groundwater salinity was an important predictor of community type. Isotopic analysis of d18O in plant stem water and foliar d13C was used to determine temporal and spatial patterns in water use and plant stress in two community dominants, slash pine, Pinus elliottii var. densa, and buttonwood, Conocarpus erectus. Both species relied heavily on groundwater, and plant stress was related to increasing groundwater salinity. The results of this work suggest that the interaction of press and pulse disturbances drive changes in community composition by causing mortality of salt-sensitive species and altering the freshwater resource.

Terrestrial ecosystems in the southeastern United States have evolved with fire as a common disturbance and as a result many natural communities require the presence of fire to persist over time. Human development precludes natural fires from occurring within these communities; however, prescribed fire is considered to be a critical tool in the effort to restore fire-dependent ecosystems after decades of fire exclusion. Direct effects of fire on individual floral and faunal species as well as benefits to biodiversity at the landscape (gamma diversity) level have largely been supported in previous research. However, information on the effects of natural and prescribed fire on plant diversity at the local level (alpha diversity) is limited, particularly for southeastern forests. The applicability of the Intermediate Disturbance Hypothesis (IDH), which suggests that the highest levels of biodiversity are found at intermediate levels of disturbance, is also untested for North Florida upland plant communities. This study compared the effects of fire on local scale mean plant species diversity by examining burned and unburned portions of three fire-dependent communities to determine if there is an effect of prescribed fire on in alpha biodiversity. Alpha biodiversity was not significantly different (p=0.433) between burned and unburned fire-dependent plant communities in northern Florida, suggesting that prescribed fire does not affect plant species diversity in these communities and/or the IDH for plant communities is not supported at the time scale tested. However, the application of prescribed fire did result in changes in abundance of species, particularly with species such as Dicanthelium acuminatum, Quercus myrtifolia, and Vaccinium myrsinites, that respond positively to fire, which may have implications for associated faunal diversity.

La agricultura ecológica se ha planteado como una posible solución paliativa a las negativas consecuencias de la intensificación agrícola. Aunque los beneficios de una agricultura más sostenible y menos intensiva son claros para la flora arvense de los campos de cereales gestionados ecológicamente, no son tan obvios para grupos de artrópodos oportunistas como son los pulgones que pueden ocasionar grandes pérdidas económicas, ni para sus enemigos naturales. Los estudios que abordan el tema de planta-artrópodo son escasos y frecuentemente se ciñen a evaluar las abundancias de ciertos grupos en vez de estudiar el impacto de la comunidad vegetal entera sobre la comunidad de artrópodos. Así que es necesario evaluar la interacción entre grupos funcionales vegetales (gramíneas, dicotiledóneas (excluyendo leguminosas) y leguminosas) y grupos funcionales de artrópodos (herbívoros succionadores y masticadores, consumidores florales, saprófagos, omnívoros, parasitoides, y predadores) para poder evaluar la efectividad real de las medidas agro-ambientales aplicadas en estas últimas décadas en la búsqueda de una gestión más sostenible.

Pine rocklands are endangered ecosystems unique to south Florida, the Bahamas and Cuba. As a result of their karstic calcium carbonate­rich soil, these systems are limited in phosphorus and nitrogen, making symbiotic associations critical to plant growth. Four leguminous species (Cajanus cajan, Chamaecrista fasciculata, Tephrosia angustissima, and Abrus precatorious) were used to determine the relationship between rhizobial partners and plant performance, and the symbiosis related gene nifH was amplified to characterize the diversity of rhizobial symbionts. Plants were grown in soils from four different south Florida pine rocklands, and a salinity treatment was added to determine how storm surge and sea level rise could affect this symbiotic relationship. While plant performance and nodulation were highly impacted by soil type, salinity did not represent a significant effect. Phylogenetic analysis determined that all four plant species were found to associate with Bradyrhizobium spp. and no rhizobial shift between salinity treatment and soil type was found.

Over the last few decades coral reefs have faced unprecedented declines in health due to natural and anthropogenic sources. Until recently few studies have examined genotypic variation of growth and thermal stress resistance in Acropora cervicornis. This study aims to assess the potential for energy trade-offs between growth and thermal stress resistance by following 120 coral fragments from 12 genotypes of Acropora cervicornis over the course of 15 months to determine average growth rates for each genotype. Following the completion of the growth observation a bleaching event occurred in the lower Florida Keys providing the opportunity for examining thermal stress resistance. We found that the coral genotype had a significant effect on growth and survival; however no significant correlation was observed between growth under normal conditions and thermal stress resistance. This result shows that there is not a trade-off between growth and thermal stress resistance and that a genotype’s ability to resist thermal stress cannot be predicted from growth under normal conditions. The lack of a trade-off facilitates intraspecific competition. For genotypes with similar thermal stress tolerances but different growth characteristics, the increase in frequency of disturbances could result in the increased abundance of faster growing genotypes relative to the slow growing genotypes. These results emphasize the importance of maintaining coral nurseries as gene banks to protect the genetic diversity of the reef area in which it is located. Through protecting a wide variety of genotypes, the likelihood of preserving those that have a high thermal tolerance, disease resistance, or faster growth rates is increased.

Increased demands on water supplies caused by population expansion, saltwater intrusion, and drought have led to water shortages which may be addressed by use of recycled water as recycled water products. Study I investigated recycled water production in Florida and California during 2009 to detect gaps in distribution and identify areas for expansion. Gaps were detected along the panhandle and Miami, Florida, as well as the northern and southwestern regions in California. Study II examined gaps in distribution, identified temporal change, and located areas for expansion for Florida in 2009 and 2015. Production increased in the northern and southern regions of Florida but decreased in Southwest Florida. Recycled water is an essential component water management a broader adoption of recycled water will increase water conservation in water-stressed coastal communities by allocating recycled water for purposes that once used potable freshwater.

Thesis (Ph. D.)--Florida State University, 2005.
Advisor: Dr. Jon Anthony Stallins, Florida State University, College of Social Sciences, Dept. of Geography. Title and description from dissertation home page (June 15, 2005). Document formatted into pages; contains xiii, 169 pages. Includes bibliographical references.

Prescribed fire is commonly used as a land management tool to enhance and maintain habitats and to mitigate wildfire risk. However, their beneficial/detrimental role in forest structure and the consequences for forest-dwelling biota is not consensual. Hence, this study aimed to assess the impact of prescribed fire in the flora and in the soil edaphic community, and to understand their evolution since the fire occurrence. This study was conducted in Baldio de Carvalhais, a private land managed by the Montis association, which was divided in four sub-areas: three areas that were managed with prescribed fire (4 months, 1 and 2 years ago); and one fourth that was not burnt recently. The data collected in each sub-area included the soil pH, electrical conductivity (EC) and organic matter (OM), as well as the composition and structure of the flora and the edaphic macrofauna. The results showed lower OM values and slightly lower pH values in the sub-areas that burnt more recently. The EC only presented lower values in the sub-area burnt recently. Regarding the vegetation, this study highlights the role of prescribed fire in promoting their diversity, the abundance, species richness and evenness of the plants. Also, the use of natural engineering seems to have contributed to an increase in abundance and diversity of the flora in one of the sub-areas. In an opposite trend, the edaphic macrofauna decrease in their richness and evenness due to the fire. This study also revealed that with the time since the fire occurrence, the flora and edaphic macrofauna in the burnt sub-areas are recovering and approaching the unburned area. Nevertheless, more temporal studies and more soil parameters are required to better insight into the impacts of prescribed burning in the ecosystem functions and their services.
O fogo controlado é geralmente usado como uma ferramenta de gestão de solos para melhorar e manter habitats e para mitigar riscos de incêndios florestais. No entanto, o seu papel benéfico / prejudicial na estrutura da floresta e as consequências para o seu biota não são consensuais. Assim, este estudo teve como objetivo avaliar o impacto do fogo controlado na flora e na comunidade edáfica do solo e compreender a sua evolução desde a ocorrência do fogo. Este estudo foi realizado no Baldio de Carvalhais, uma propriedade privada administrada pela associação Montis, e que foi dividida em quatro subáreas: três áreas geridas com fogo controlado (há 4 meses, 1 e 2 anos); e uma quarta que não foi queimada recentemente. Os dados recolhidos em cada subárea incluíram o pH do solo, a condutividade elétrica (CE) e a matéria orgânica (MO), assim como a composição e estrutura da flora e da macrofauna edáfica. Os resultados mostraram valores mais baixos de MO e valores de pH ligeiramente mais baixos nas subáreas ardidas mais recentemente. A CE apresentou apenas valores mais baixos na subárea queimada recentemente. Em relação à vegetação, este estudo destaca o papel do fogo prescrito na promoção de sua diversidade, abundância, riqueza de espécies e uniformidade das plantas. Além disso, o uso da engenharia natural parece ter contribuído para um aumento na abundância e diversidade da flora numa das subáreas. De modo oposto, a macrofauna edáfica diminuiu a sua riqueza e uniformidade devido ao fogo. Este estudo também revelou que, com o tempo decorrido desde a ocorrência do incêndio, a flora e a macrofauna edáfica nas subáreas queimadas estão-se recuperando e aproximando da área não queimada. No entanto, mais estudos temporais e mais parâmetros do solo são necessários para uma melhor compreensão dos impactos do fogo controlado nas funções do ecossistema e nos seus serviços.
Mestrado em Ecologia Aplicada