Browsing by Subject "Land cover"

Now showing 1 - 8 of 8

Open Access
A DECISION SUPPORT TOOL FOR PREDICTING WATER QUALITY BASED ON LAND COVER
(2011-04-28) Baker, Brittney
Managers at Marine Corps Base Camp Lejeune must evaluate the environmental impacts of their proposed development plans. The effect of land cover changes on water quality is an important consideration for these evaluations. An interactive geospatial tool was developed in 2009. The tool allows managers to interactively select their proposed development site and input what the proposed land cover will be for the site. The tool returns the changes in average ammonium concentration in the tributary creeks. The tool incorporates water quality data collected by the DCERP project from 2008-2009 to drive the prediction model. The purpose of this project was to (1) improve usability of the tool to make it a spatial decision support system, (2) update the water quality data used to drive the statistics of the water quality prediction models, and (3) determine if using the National Land Cover Dataset (NLCD) from 2006 instead of the 2001 NLCD changes the relationship between land cover predictors and water quality response variables. Tool usability was enhanced by adding in-tool and external help menus, creating a user guide, and adding the ability to name and save outputs. The updated tool allows the user to run multiple land development scenarios for comparison without overwriting the previous results. Adding additional water quality data from 2007-2010 resulted in fewer significant water quality prediction models. The most predictive of these models was for organic nitrogen. The model, predicted by barren (rock/sand/clay), shrub/scrub, and grassland/herbaceous land covers, was incorporated into the decision support tool. Using land cover data from 2001 and 2006 allowed the same two water quality parameters to be predicted: NOx and ON. Managers at Marine Corps Base Camp Lejeune can use this data driven Spatial Decision Support System to evaluate how different development scenarios will affect the concentration of organic nitrogen in the tributary creeks on base.
Open Access
Land Cover Change and Ecosystem Services on the North Carolina Piedmont 1985 to 2005
(2008-04-25T20:38:43Z) Donohue, Michael John
Analyses of ecosystem processes are advanced through remote sensing and geostatistical modeling methods capable of capturing landscape pattern over broad spatial and temporal scales. Many ecological studies rely on land cover data classified from satellite imagery. In this, changes in land cover are often presumed to correlate with changes in ecosystem processes or services provided by ecosystems (e.g., watershed protection). Documenting changes in land cover requires that images be classified over time, often using historical images to document landscape change. But this is difficult to do for historical images because we cannot ground-truth old images, lacking actual land cover data from the past. I developed a land cover classification scheme using a classification and regression tree (CART) model generated from 2001 National Land Cover Dataset (NLCD) and Summer, Fall, and Winter triplets of Landsat 5 Thematic Mapper (TM) imagery. The model is robust to inter-annual variability in surface reflectance, and thus can be extended in time to classify land cover from images from any time, past or future. The model was used to predict land cover from 1985 to 2005, for a study region in the Piedmont of North Carolina. Temporal and spatial analyses focused on ecosystem services of carbon sequestration and biodiversity support as affected by forest fragmentation. This study offers a landscape-level identification of the relationships between spatial and temporal development patterns and the provision of ecosystem services. The project also represents the creation of a multi-annual land cover classification dataset of which few exist, thus providing a framework for further studies of landscape pattern and ecological processes.
Open Access
Land Use Land Cover in the Western Ghats, India
(2013-04-26) Gerlach, Paul; Hubbard, Malissa; Norment, Elizabeth
In India’s Western Ghats mountain range, a UNESCO World Heritage Site and Conservation International biodiversity hotspot, human-caused habitat loss threatens many native species. A number of protected areas have been created to provide a refuge for these species and prevent further habitat loss. However, encroaching development continues to threaten these delicate ecosystems. Despite the area’s environmental value, there is no reliable, high-resolution land use land cover (LULC) map that would allow managers to estimate the extent and distribution of development as well as habitat condition and connectivity across the region. Using ASTER imagery, we conducted LULC classifications of 6 protected areas and their surroundings (20 km buffers). Separate classifications were conducted on Anshi-Dandeli National Park, Nagarahole and Bandipur National Parks, BRT Wildlife Sanctuary, and Kudremukh and Bhadra Wildlife Sanctuaries, for a total of four classification regions. We conducted both supervised maximum likelihood and unsupervised ISODATA classifications. Accuracy of the supervised classifications was higher than accuracy of the unsupervised classifications, with values ranging from 75.6-84.4%. Forest class accuracy ranged from 74% - 91%. We used the LULC classifications to assess the amount of forest cover within the protected areas and in the 20 km surrounding buffer. Within the classifications, 45-67% of the land is forested, while 17-35% of the land has been cleared for human use. We also conducted pilot analyses of forest fragmentation, patch connectivity, and human-affected areas in different parks. The LULC maps will be used to help managers set conservation goals and establish land use baselines for the region.
Open Access
Micro-topographic roughness analysis (MTRA) highlights minimally eroded terrain in a landscape severely impacted by historic agriculture
(Remote Sensing of Environment, 2019-03-01) Brecheisen, ZS; Cook, CW; Heine, PR; Richter, DDB
© 2018 Elsevier Inc. The 190 km2 Calhoun Critical Zone Observatory in the Piedmont region of South Carolina, USA lies in an ancient, highly weathered landscape transformed by historic agricultural erosion. Following the conversion of largely hardwood forests to cultivated fields and pastures for ~200 years, excess runoff from fields led to extreme sheet, rill, and gully erosion across the landscape. Roads, terraces, and a variety of other human disturbances have increased the landscape's surface roughness. By the 1950s, cultivation-based agriculture was largely abandoned across most of the Southern Piedmont due to soil erosion, declining agricultural productivity, and shifting agricultural markets. Secondary forests, dominated by loblolly and shortleaf pines, have since regrown on much of the landscape, including the 1500 km2 Sumter National Forest, which was purchased from farmers and private land owners in the 1930s. Although this landscape was intensively farmed for approximately 150 years, there are a few hardwood forest stands and even entire small watersheds that have never been plowed and degraded by farming. Such relatively old hardwood stands and watersheds comprise relic landforms whose soils, regoliths, and vegetation are of interest to hydrologists, environmental historians, biogeochemists, geomorphologists, geologists, pedologists, and others interested in understanding the legacy of land-use history in this severely altered environment. In this work we champion the need for high-resolution terrain mapping and demonstrate how Light Detection And Ranging (LiDAR) digital elevation model (DEM) data and microtopographic terrain roughness analyses (MTRA) can be used to infer land use history and management. This is accomplished by analyzing fine scale variation in terrain slope across the 1190 km2 CCZO using data derived from three independent and overlapping LiDAR datasets at varying spatial resolutions. Terrain slope variability MTRA is further compared to three other methods of capturing and quantifying fine-scale surface roughness. We lastly demonstrate how these analyses can be employed in concert with historic aerial photography from the 1930's, contemporary Landsat remote sensing data, and ecological field data to identify reference relic landforms: hardwood stands, hillslopes, and small watersheds that have experienced minimal anthropogenic erosion for study and conservation.
Open Access
Protected Area Impacts on Land Cover in Mexico
(2013-04-15) Santiago-Ávila, Francisco J.
Although national and international efforts to mitigate deforestation during the last few decades have had some limited impact, they have failed to substantially slow the loss of tropical forests. This MP applies an approach for providing more evidence on what has worked or not worked in terms of conservation policies intended to reduce tropical natural land cover. Specifically, the work and approaches used in my analysis should help to illuminate the tradeoffs currently facing Mexico, a country which is seriously considering pursuing REDD policies, but also knows it would not be without economic costs. My main objective is to answer the question: "have conservation parks affected change in land cover in Mexico?” while a related objective is to assess if some types of parks have had reliably more impact. Due to the nonrandom establishment of protected areas (PAs), I employ a matching approach (propensity score) in order to construct a plausible counterfactual by controlling explicitly for land characteristics that proved to be significant drivers of both land cover change and protection status. My results indicate not only that my approach improved impact estimates, but also, in particular, that PAs lower land cover change pressure by 3.1%, and that strict protection seems to avoid more land cover change (5.3%) than loose (multi-use) protection (2.7%). While these results are suggestive, I would recommend also trying to get better and more data to test their robustness.
Open Access
Protected Area Impacts on Land Cover in Mexico
(2013-04-15) SantiagoÁvila, Francisco J
Although national and international efforts to mitigate deforestation during the last few decades have had some limited impact, they have failed to substantially slow the loss of tropical forests. This MP applies an approach for providing more evidence on what has worked or not worked in terms of conservation policies intended to reduce tropical natural land cover. Specifically, the work and approaches used in my analysis should help to illuminate the tradeoffs currently facing Mexico, a country which is seriously considering pursuing REDD policies, but also knows it would not be without economic costs. My main objective is to answer the question: "have conservation parks affected change in land cover in Mexico?” while a related objective is to assess if some types of parks have had reliably more impact. Due to the nonrandom establishment of protected areas (PAs), I employ a matching approach (propensity score) in order to construct a plausible counterfactual by controlling explicitly for land characteristics that proved to be significant drivers of both land cover change and protection status. My results indicate not only that my approach improved impact estimates, but also, in particular, that PAs lower land cover change pressure by 3.1%, and that strict protection seems to avoid more land cover change (5.3%) than loose (multi-use) protection (2.7%). While these results are suggestive, I would recommend also trying to get better and more data to test their robustness.
Open Access
The Effects of Land Use Change on Carnivore Use of Wildlife Dispersal Routes in Ranthambhore Tiger Reserve, India
(2017-04-27) Ranganathan, Priya
As the human population increases and climate change exacerbates resource scarcity, India’s wildlife faces the increasing threat of fragmentation and habitat loss in a human-centric landscape. The wild exists in small semi-isolated pockets, connected sparsely, if at all, by wildlife corridors. Such wildlife corridors may be the last hope for charismatic megafauna such as the Bengal tiger (Panthera tigris tigris). This project assesses the impacts of encroachment and land use change on the use of two wildlife dispersal (corridors) connecting Ranthambhore National Park (RNP) to other intact forest patches in the larger Ranthambhore Tiger Reserve (RTR) by the tiger and other large carnivores. The research objectives are: (1) to quantify land use and land cover change between 2011 and 2016 in RTR; (2) to assess the effects of this change on the two major wildlife dispersal corridors; and (3) to better understand how this affects land cover preference and use by tigers. Field data collection of wildlife presence and human encroachment in the two corridors was carried out during May-June 2016, and geospatial analysis was used to generate maps for WWF-India, as well as to study the changes in the landscape over the five-year period. Major threats to corridors were found to be the expansion of agricultural land, sand mining, overgrazing of forest vegetation by livestock, and urban expansion. Agricultural expansion has caused a decline in forest and ravine land cover, which are preferred by dispersing carnivores. Most threats were concentrated around the northwest corridor, making it a conservation priority. The southeast corridor is also heavily used by dispersing tigers as it is mostly characterized by ravines, a preferred habitat type; however, flattening of ravines for agricultural expansion and mining brings carnivores into proximity with humans, increasing the potential for conflict in the region. Based on these results, we recommend increased protection of the buffer zone of the northwest corridor and suggest that remaining efforts be put towards conservation education and stricter regulation of land use practices in areas surrounding corridors and intact habitat patches.
Open Access
Vertical Structure, Horizontal Cover, and Temporal Change of the North Carolina Piedmont (1985-2005)
(2009) Sexton, Joseph O.
An ecosystem is a community of organisms interacting with its environment, and landscapes are spatially interactive ecosystems. Earth's burgeoning human population demands ever more from finite ecosystems; but if managed well, landscapes can sustain their provision of resources and services and adapt to fulfill the changing human appetite. Management relies on sound information, and managing landscape change requires reliable spatio-temporal databases of ecologically relevant information. Remote sensing technologies fill this niche, providing increasingly large and diverse datasets, but the algorithms to extract information from the data must be developed. I developed and compared three remotely sensed measurements of forest canopy height to one another and to in situ field measurements. Both the precision and the accuracy (as well as the cost) of the measurements sorted along an axis of spatial scale, with Light Detection and Ranging (lidar) measurements proving most reliable at fine scales but prohibitively expensive over large areas and various radar technologies more appropriate for larger areas, especially when calibrated to the more accurate and precise lidar measurements. I also adapted traditional, single-time landcover classification algorithms to extract dense time series of categorical landcover maps from archival multi-spectral satellite images. These measurements greatly expand the potential spatio-temporal scope of landscape ecology and management, facilitating a shift away from data-imposed reliance on "space-for-time substitution" and loosely connected case studies toward robust, statistical analysis based on consistent information.

Browsing by Subject "Land cover"

Results Per Page

Sort Options