Current Search: Vegetation dynamics (x)
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- Title
- Effect of external pH on cyanobacterial pigment expression.
- Creator
- West, Maria., Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
- Abstract/Description
-
Cyanobacteria are classified as alkalophiles despite their preferential uptake of the acidic form of dissolved inorganic carbon. Long term impacts of external pH on the expression of photosynthetic and structural pigments in Schizothrix calcicola were investigated as potential contributing factors to this phenomenon. More robust cell walls in S. calcicola at pH
Show moreCyanobacteria are classified as alkalophiles despite their preferential uptake of the acidic form of dissolved inorganic carbon. Long term impacts of external pH on the expression of photosynthetic and structural pigments in Schizothrix calcicola were investigated as potential contributing factors to this phenomenon. More robust cell walls in S. calcicola at pH <7 are suggested by significantly greater expression of myxoxanthophylls. Direct and indirect physiological costs of altering cell walls may contribute to S. calcicola's depressed growth at acidic pH. Comparison of chlorophylls expression suggests that alkaline rather than neutral external pH is only beneficial for S. calcicola growth in absence of nutrient limitation. While the cyanobacterial biomarker ratio of chlorophylls to echinenone was stable across the pertinent pH range of 6-8, other pigment ratios in S. calcicola were affected by pH with an approximately two week lag between the change of pH and the corresponding change of pigment expression.
Show less - Date Issued
- 2010
- PURL
- http://purl.flvc.org/FAU/2795335
- Subject Headings
- Environmental toxicology, Cyanobacteria, Environmental aspects, Ecosystem management, Vegetation dynamics
- Format
- Document (PDF)
- Title
- The impact of willow encroachment on water and carbon exchange in the vegetation of a subtropical wetland.
- Creator
- Budny, Michelle L., Benscoter, Brian, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
- Abstract/Description
-
Shortened periods of inundation due to water management have led to the encroachment and expansion of Carolina willow (Salix caroliniana) in sawgrass (Cladium jamaicense) marsh communities. Morphologic and physiologic differences between sawgrass and willow have potential consequences for microhabitat conditions and ecosystem function such as a reduction in temperatures and light availability and changes in primary productivity. Since it is a woody shrub, willow is often assumed to exhibit...
Show moreShortened periods of inundation due to water management have led to the encroachment and expansion of Carolina willow (Salix caroliniana) in sawgrass (Cladium jamaicense) marsh communities. Morphologic and physiologic differences between sawgrass and willow have potential consequences for microhabitat conditions and ecosystem function such as a reduction in temperatures and light availability and changes in primary productivity. Since it is a woody shrub, willow is often assumed to exhibit higher rates of transpiration than non woody plants, which in turn can affect photosynthesis and carbon exchange and ultimately wetland water management. In this study willow was found to have higher rates of stomatal conductance (gs) and photosynthesis (Anet) than sawgrass. However, sawgrass had greater intrinsic water use efficiency (WUE) than willow. This suggests that willow is capable of greater gas exchange and carbon assimilation than sawgrass but requires more water. Understanding the implications of willow expansion will improve landscape models of wetland water and carbon exchange and inform water management decisions.
Show less - Date Issued
- 2015
- PURL
- http://purl.flvc.org/fau/fd/FA00004350, http://purl.flvc.org/fau/fd/FA00004350
- Subject Headings
- Biogeochemistry, Ecosystem management, Surfaces (Technology) -- Measurement, Vegetation dynamics, Wetland ecology
- Format
- Document (PDF)
- Title
- VEGETATION DYNAMICS AT DIFFERENT SPATIO-TEMPORAL SCALES IN FREQUENTLY BURNED MIXED CONIFER FORESTS, NORTHERN SIERRA NEVADA RANGE, CALIFORNIA.
- Creator
- Paudel, Asha, Markwith, Scott H., Florida Atlantic University, Department of Geosciences, Charles E. Schmidt College of Science
- Abstract/Description
-
Mixed conifer forests in the Sierra Nevada, California, face threats from frequent highseverity fire associated with climate change and fuel accumulation leading to vegetation shifts at local and landscape scales. Under rapid climate change, a clear understanding of how vegetation responds to single and/or repeated wildfires is still lacking and needs to be investigated. Using field and satellite data, the effects of wildfire on vegetation dynamics were explored at the plot and landscape...
Show moreMixed conifer forests in the Sierra Nevada, California, face threats from frequent highseverity fire associated with climate change and fuel accumulation leading to vegetation shifts at local and landscape scales. Under rapid climate change, a clear understanding of how vegetation responds to single and/or repeated wildfires is still lacking and needs to be investigated. Using field and satellite data, the effects of wildfire on vegetation dynamics were explored at the plot and landscape levels in this dissertation project. Results from the field data suggest that management activities may be required in high-severity burned areas to restore dominance of mixed conifer forests and regain historical species composition in areas where live trees persist. Results from satellite data suggested that large shrub patches, created after mixed severity fire, fragment the homogenous mixed conifer dominated forest of the Sierra Nevada to create a more heterogeneous landscape, however the extent of diversity and fragmentation were dependent on fire severity and scales. Natural wildfires may restore landscape heterogeneity to conditions equivalent to the pre-Columbian era, but effects under the projected climate change scenario for 21st century remain uncertain. Mixed conifer dominated forests are predicted to be the dominant component of the Sierra Nevada landscape under historical fire probabilities and excluding higher probability of high-severity fire over the next 100 years.
Show less - Date Issued
- 2022
- PURL
- http://purl.flvc.org/fau/fd/FA00013966
- Subject Headings
- Vegetation dynamics, Climate change, Fire ecology, Wildfires--Management
- Format
- Document (PDF)
- Title
- Using scientific visualization to enhance historical aerial photography in documenting vegetation change over time: Melaleuca quinquenervia, a case study.
- Creator
- Morrow, Victoria Elizabeth, Florida Atlantic University, Roberts, Charles
- Abstract/Description
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The objective of this thesis is to conduct a time series analysis of melaleuca growth in the littoral zone of western Lake Okeechobee, using historical aerial photography and Scientific Visualization, Image Enhancement and Image Exploration techniques are examined and compared. Problems associated with creating a time series analysis using aerial photography for use in an integrated GIS are explored. A spatial analysis of environmental factors affecting the growth of Melaleuca quinquenervia...
Show moreThe objective of this thesis is to conduct a time series analysis of melaleuca growth in the littoral zone of western Lake Okeechobee, using historical aerial photography and Scientific Visualization, Image Enhancement and Image Exploration techniques are examined and compared. Problems associated with creating a time series analysis using aerial photography for use in an integrated GIS are explored. A spatial analysis of environmental factors affecting the growth of Melaleuca quinquenervia is conducted, and an analysis of the validity of such statistical inferences for use in future decision making is examined. Results indicate that managed water levels inside Lake Okeechobee did indeed have an effect on the rate of growth of Melaleuca quinquenervia. Recommendations for future data gathering and study are outlined.
Show less - Date Issued
- 1997
- PURL
- http://purl.flvc.org/fcla/dt/15395
- Subject Headings
- Melaleuca quinquenervia--Monitoring--Florida--Okeechobee, Lake, Vegetation dynamics, Vegetation monitoring, Okeechobee, Lake (Fla)
- Format
- Document (PDF)
- Title
- Development of a remote sensing technique for woody vegetation in Rotenberger Wildlife Management Area.
- Creator
- Franklin, Sarah., Charles E. Schmidt College of Science, Department of Geosciences
- Abstract/Description
-
The Florida Fish and Wildlife Conservation Commission lacks a viable method for monitoring woody vegetation in expansive wetland communities, such as the Florida Everglades. This study used aerial photographs of Rotenberger Wildlife Management Area in southeastern Palm Beach County, Florida to develop techniques for remotely monitoring changes in woody vegetation. Imagery from 2006, 2008, and 2010 were classified into woody and non-woody categories using Adobe Photoshop's Magic Wand Tool....
Show moreThe Florida Fish and Wildlife Conservation Commission lacks a viable method for monitoring woody vegetation in expansive wetland communities, such as the Florida Everglades. This study used aerial photographs of Rotenberger Wildlife Management Area in southeastern Palm Beach County, Florida to develop techniques for remotely monitoring changes in woody vegetation. Imagery from 2006, 2008, and 2010 were classified into woody and non-woody categories using Adobe Photoshop's Magic Wand Tool. Selection was performed with a bias toward over classification, as project objectives required identifying as many trees as possible. Classified pixels in Time 1 within 4 feet (2 pixels) of classified pixels from Time 2 were considered the same canopy. Overall accuracy for the study was 98%.
Show less - Date Issued
- 2011
- PURL
- http://purl.flvc.org/FAU/3175018
- Subject Headings
- Environmental monitoring, Remote sensing, Vegetation dynamics, Ecosystem management
- Format
- Document (PDF)
- Title
- The cascading impacts of vegetation on peat soil properties and crayfish survival in the Florida everglades.
- Creator
- Chapman, Alexander, Benscoter, Brian, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
- Abstract/Description
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Changes in vegetation may influence the quality and quantity of the underlying organic peat soils and have impacts on faunal populations. My goal was to determine whether shifts from native slough communities to invasive cattail in the Florida Everglades could affect peat characteristics that could cascade to impact the dry season survival of crayfish (Procambarus fallax). I contrasted peat soils from native slough and cattail-invaded sites as alternative dry-season burrowing substrates for...
Show moreChanges in vegetation may influence the quality and quantity of the underlying organic peat soils and have impacts on faunal populations. My goal was to determine whether shifts from native slough communities to invasive cattail in the Florida Everglades could affect peat characteristics that could cascade to impact the dry season survival of crayfish (Procambarus fallax). I contrasted peat soils from native slough and cattail-invaded sites as alternative dry-season burrowing substrates for crayfish. Cattail peat had higher average bulk density and inorganic content within the first ten centimeters of the soil profile. Crayfish showed marginally greater initial burrowing success in slough peat than in cattail peat but survival was equivalent in both peat soils and high overall. Understanding these indirect linkages between vegetation and crayfish populations in the Everglades can provide insight on the consequences of plant invasion on ecosystem trophic dynamics.
Show less - Date Issued
- 2014
- PURL
- http://purl.flvc.org/fau/fd/FA00004091, http://purl.flvc.org/fau/fd/FA00004091
- Subject Headings
- Crayfish (Ecology), Ecosystem management, Everglades National Park (Fla.), Vegetation dynamics -- Florida -- Everglades National Park
- Format
- Document (PDF)
- Title
- Studies of specific gene expression of phosphate transporters in sawgrass (Cladium jamaicense crantz) and cattail (Typha domingensis pers.).
- Creator
- Lin, Li, Charles E. Schmidt College of Science, Department of Biological Sciences
- Abstract/Description
-
In the Florida Everglades, sawgrass has been displaced by cattail, predominantly resulting from phosphate enrichment. It has been found that phosphate transporters and arbuscular mycorrhizal (AM) fungi play an important role in phosphate uptake in the plants. This study aimed to reveal the symbiosis between AM fungi and sawgrass and cattail and identify the phosphate transporters, especially AM-specific phosphate transporters in these two species. AM colonization was only found in sawgrass...
Show moreIn the Florida Everglades, sawgrass has been displaced by cattail, predominantly resulting from phosphate enrichment. It has been found that phosphate transporters and arbuscular mycorrhizal (AM) fungi play an important role in phosphate uptake in the plants. This study aimed to reveal the symbiosis between AM fungi and sawgrass and cattail and identify the phosphate transporters, especially AM-specific phosphate transporters in these two species. AM colonization was only found in sawgrass roots, not cattail, at low phosphate concentrations in lab and field samples by trypan blue staining. AM fungi could increase sawgrass growth and had little effect on cattail growth. Four phosphate transporters were identified in sawgrass. CjPT1, CjPT2 and CjPT3 were expressed in roots and shoots independent of AM fungi and phosphate availability, while CjPT4 appeared to be an AM regulated phosphate transporter gene and its expression was induced by AM fungi.
Show less - Date Issued
- 2010
- PURL
- http://purl.flvc.org/FAU/1930493
- Subject Headings
- Phosphorus, Physiological transport, Soil stabilization, Vegetation dynamics, Ecosystem management, Soil mineralogy, Plant physiology
- Format
- Document (PDF)
- Title
- Patterns of inorganic phosphate and carbohydrate allocation in sawgrass (Cladium jamaicense Crantz) and southern cattail (Typha domingensis Pers.) grown at low and high phosphate levels.
- Creator
- Hill, Brian, Charles E. Schmidt College of Science, Department of Biological Sciences
- Abstract/Description
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In recent history, C. jamaicense has been displaced by another native monocot, T. domingensis, predominantly resulting from increased phosphorous enrichment in the Everglades. This study aimed to elucidate these two species responses to low and high [Pi] in terms of allocation, photosynthate partitioning and growth. C. jamaicense growth was independent of Pi, while T. domingensis growth increased with [Pi]. Under high [Pi], allocation to younger T. domingensis shoots occurred, while C....
Show moreIn recent history, C. jamaicense has been displaced by another native monocot, T. domingensis, predominantly resulting from increased phosphorous enrichment in the Everglades. This study aimed to elucidate these two species responses to low and high [Pi] in terms of allocation, photosynthate partitioning and growth. C. jamaicense growth was independent of Pi, while T. domingensis growth increased with [Pi]. Under high [Pi], allocation to younger T. domingensis shoots occurred, while C. jamaicense shoots retained more [Pi], while low [Pi] resulted in homogeneous allocation patterns for both species. Additionally, Pi deficiencies induced carbohydrate levels in older shoots of T. domingensis, while [Pi] had no effect on photosynthate partitioning patterns in C. jamaicense. ACP activity was induced by Pi deficiency in all T. domingensis shoots and increased with shoot age, while no effect was observed in C. jamaicense. Results indicate these two species differ in allocation strategies when [Pi] is altered.
Show less - Date Issued
- 2009
- PURL
- http://purl.flvc.org/FAU/238480
- Subject Headings
- Nitrogen-fixing algae, Biogeochemical cycles, Phosphorus, Psychological transport, Soil stabilization, Ecosystem management, Vegetation dynamics
- Format
- Document (PDF)
- Title
- A comparison of pixel based and object based vegetation community classification in the Arthur R. Marshall Loxahatchee National Wildlife Refuge.
- Creator
- Barone, Dorianne M., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Geosciences
- Abstract/Description
-
Pixel based and object based vegetation community classification methods were performed using 30 meter spatial resolution Landsat satellite imagery of the Arthur R. Marshall Loxahatchee National Wildlife Refuge (Refuge), a remnant of the northern Everglades. Supervised classification procedures using maximum likelihood and parallelepiped algorithms were used to produce thematic maps with the following vegetation communities : wet prairie, sawgrass, cattail, tree island, brush, aquatic/open...
Show morePixel based and object based vegetation community classification methods were performed using 30 meter spatial resolution Landsat satellite imagery of the Arthur R. Marshall Loxahatchee National Wildlife Refuge (Refuge), a remnant of the northern Everglades. Supervised classification procedures using maximum likelihood and parallelepiped algorithms were used to produce thematic maps with the following vegetation communities : wet prairie, sawgrass, cattail, tree island, brush, aquatic/open water. Spectral data, as well as NDVI, texture and principal component data were used to produce vegetation community classification maps. The accuracy levels of the thematic maps produced were calculated and compared to one another. The pixel based approach using the parallelepiped classification algorithm on the spectral and NDVI dataset had the highest accuracy level. A generalized form of this classification using only three vegetation communities (all wet prairie, tree island/brush and aquatic/open water) was compared to a previously published classification which used 1987 SPOT imagery in order to extract information on possible vegetation community transitions that are occurring within the Refuge. Results of the study indicate that 30 meter spatial resolution may be useful for understanding broad vegetation community trends but not species level trends. Pixel based procedures provide a more accurate classification than object based procedures for this landscape when using 30 meter imagery. Lastly, since 1987 there may be a trend of tree island/brush communities replacing wet prairie communities in the northern part of the Refuge and a transition to wet prairie communities in place of tree island/brush communities in the southern portion of the Refuge.
Show less - Date Issued
- 2008
- PURL
- http://purl.flvc.org/FAU/58002
- Subject Headings
- Ecosystem management, Vegetation dynamics, Vegetation classification, Spatial ecology, Mathematical models
- Format
- Document (PDF)
- Title
- A Regression Model for Predicting Percent Built-up Land Cover from Remotely Sensed Imagery of Pucallpa, Peru.
- Creator
- Sprague, Drake H., Garcia Quijano, Maria, Florida Atlantic University
- Abstract/Description
-
Accurate information about built-up land cover and population density is essential for sustainable urban growth, especially in lesser developed countries. Unfortunately, this data is often too expensive for planning agencies, prompting use of outdated and unreliable information. As a proxy for estimating population density, a linear regression model is proposed to test the relationship between the percentage of built-up land cover and vegetation in Pucallpa, Peru. Expert knowledge, low-cost...
Show moreAccurate information about built-up land cover and population density is essential for sustainable urban growth, especially in lesser developed countries. Unfortunately, this data is often too expensive for planning agencies, prompting use of outdated and unreliable information. As a proxy for estimating population density, a linear regression model is proposed to test the relationship between the percentage of built-up land cover and vegetation in Pucallpa, Peru. Expert knowledge, low-cost moderate-resolution sate llite imagery, and high-resolution Google Earth images are used to estimate the percentage of built-up land cover at randomly assigned reference locations. Normalized Difference Vegetation Index (NDVI) data, acquired at each reference point, is the independent variable in a linear regression model constructed to predict the percentage of built-up land cover. The results were successful, with an adjusted R2 = 0.774 at 95% confidence. Strength and accuracy are further evaluated against zoning maps and population estimates provided by local authorities.
Show less - Date Issued
- 2007
- PURL
- http://purl.flvc.org/fau/fd/FA00000966
- Subject Headings
- Geodynamics, Geographic information systems, Land use, Rural--Government policy--Peru, Vegetation dynamics--Peru--Pucallpa
- Format
- Document (PDF)
- Title
- The Effect of Vegetation (Ipomoea pes-caprae) on Leatherback (Dermochelys coriacea) Nest Productivity.
- Creator
- Conrad, Jeremy R., Wyneken, Jeanette, Florida Atlantic University
- Abstract/Description
-
From 2004 - 2007, the beach at Sandy Point National Wildlife Refuge (St. Croix, USVI) experienced low summer erosion, which allowed native pioneer vegetation to spread seaward and invade leatherback-nesting areas. The encroachment of vegetation reduced nest survival. Here I describe the results of an experimental assessment of vegetation control methods and of the effects of native vegetation on leatherback hatching and emergence success. I tested four treatments: (i) naturally vegetated, (ii...
Show moreFrom 2004 - 2007, the beach at Sandy Point National Wildlife Refuge (St. Croix, USVI) experienced low summer erosion, which allowed native pioneer vegetation to spread seaward and invade leatherback-nesting areas. The encroachment of vegetation reduced nest survival. Here I describe the results of an experimental assessment of vegetation control methods and of the effects of native vegetation on leatherback hatching and emergence success. I tested four treatments: (i) naturally vegetated, (ii) herbicide treated vegetation, (iii) mechanically removed above ground vegetation, and (iv) non-vegetated (control) plots. Nests were relocated into each of the plot types then left to incubate naturally. Hatching and emergence success was reduced when vegetation was present. Vegetation was not adequately controlled by any of the methods tested. The results identify future research needs for the development of appropriate management to control the native vegetation and enhance leatherback nest productivity.
Show less - Date Issued
- 2008
- PURL
- http://purl.flvc.org/fau/fd/FA00000736
- Subject Headings
- Vegetation dynamics, Wildlife habitat improvement, Sandy Point National Wildlife Refuge (United States Virgin Islands), Leatherback turtle--Habitat--Conservation
- Format
- Document (PDF)
- Title
- Predicting leatherback sea turtle sex ratios using spatial interpolation of nesting beach temperatures.
- Creator
- Weston, Emily G., Wyneken, Jeanette, Charles E. Schmidt College of Science, Department of Biological Sciences
- Abstract/Description
-
Sex determination in leatherback sea turtles is directed primarily by the temperatures a clutch experiences during the middle third of development. Warmer temperatures tend to produce females will cooler temperatures yield males. Nest temperatures can vary spatially and temporally. During the 2010 and 2011 nesting seasons, this study estimated the hatchling sex ratio of leatherback sea turtles on Sandy Point National Wildlife Refuge (SPNWR), St. Croix, U.S. Virgin Islands. I measured sand...
Show moreSex determination in leatherback sea turtles is directed primarily by the temperatures a clutch experiences during the middle third of development. Warmer temperatures tend to produce females will cooler temperatures yield males. Nest temperatures can vary spatially and temporally. During the 2010 and 2011 nesting seasons, this study estimated the hatchling sex ratio of leatherback sea turtles on Sandy Point National Wildlife Refuge (SPNWR), St. Croix, U.S. Virgin Islands. I measured sand temperatures from May- August and across the spatial range of leatherback nesting habitat. I spatially interpolated those temperatures to create maps that predicted temperatures for all nests incubating on SPWNR. Nest temperatures were also directly measured and compared with predicted nest temperatures to validate the prediction model. Sexes of dead-in-nest hatchlings and full term embryos were used to confirm the sex-temperature response. The model showed that microclimatic variation likely impacts the production of both sexes on SPNWR.
Show less - Date Issued
- 2013
- PURL
- http://purl.flvc.org/fau/fd/FA0004071
- Subject Headings
- Leatherback turtle -- Habitat -- St. Croix -- Sandy Point National Wildlife Refuge (United States Virgin Islands), Loggerhead turtle -- Effect of temperature on, Sandy Point National Wildlife Refuge (United States Virgin Islands), Sea turtles -- Nests -- St. Croix -- Sandy Point National Wildlife Refuge (United States Virgin Islands), Sex determination, Genetic, Sex ratios, Vegetation dynamics
- Format
- Document (PDF)