809 research outputs found

    Predicting Presence of Amphibian Species Using Features Obtained from GIS and Satellite Images

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    The construction of transport infrastructure is often preceded by an environmental impact assessment procedure, which should identify amphibian breeding sites and migration routes. However, the assessment is very difficult to conduct because of the large number of habitats spread out over a vast expanse, and the limited amount of time available for fieldwork. We propose utilizing local environmental variables that can be gathered remotely using only GIS systems and satellite images together with machine learning methods. In this article, we introduce six new and easily extractable types of environmental features. Most of the features we propose can be easily obtained from satellite imagery and spatial development plans. The proposed feature space was evaluated using four machine learning algorithms, namely: a C4.5 decision tree, AdaBoost, random forest and gradient-boosted trees. The obtained results indicated that the proposed feature space facilitated prediction and was comparable to other solutions. Moreover, three of the new proposed features are ranked most important; these are the three dominant properties of the surroundings of water reservoirs. One of the new features is the percentage access from the edges of the reservoir to open areas, but it affects only a few species. Furthermore, our research confirmed that the gradient-boosted trees were the best method for the analyzed dataset

    Classification of Depressional Wetlands in the Great Plains and Development of a Sampling Manual to Predict Playa Ecosystem Services

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    Most depressional wetlands in the Great Plains, an area where wetland losses are estimated to be over 50%, exist in highly cultivated landscapes. The depressional wetlands of the Great Plains include prairie-potholes in the Prairie Pothole Region and playas in the High Plains Region. Both prairie-pothole and playa wetlands provide a host of ecosystem services to society, but service provisioning is greatly influenced by land-use practices that occur both in the wetland and in the surrounding watershed. The most common wetland classification system used to group Great Plains wetlands by type often combines wetlands with of functionally different types into a single grouping, thereby hampering efforts to evaluate ecosystem service provisioning. Thus, my objectives were to 1) develop methodologies, and associated keys, that use aerial and/or satellite imagery and other readily available data sources to place pothole and playa wetlands into hydrogeomorphic function focused groupings to facilitate ecosystem-service assessments, 2) develop a process to remotely determine metrics needed to apply preexisting predictive ecosystem-service models in the playa region and rank the models according to ease of use, and 3) develop a sampling manual for playa wetlands that incorporates the playa-specific key and associated models. Using remotely sensed data, I observed the geomorphic setting of 200 randomly selected palustrine wetlands in each of the two regions and developed a hydrogeomorphic classification key specific to each region. The key included 5 Prairie Pothole Region classes with 12 subclasses and 4 High Plains Region classes with 9 subclasses. The predictive playa ecosystem-service models I evaluated included quantified contaminant filtration, contaminant concentration, pesticide residue, sediment depth, floodwater storage, greenhouse-gas flux, soil organic carbon, plant species richness, amphibian species richness, waterfowl abundance, and avian species richness. I ranked each of these ecosystem-service models by ease of use. The ranking of models resulted in the abiotic-service models being identified as the simplest models to apply and biotic service models as the most complex. I then incorporated the playa-specific hydrogeomorphic key, model rankings and application processes into a sampling manual. The sampling manual included the High Plains Region key and instructions for remotely estimating 10 different playa ecosystem services. This manual will facilitate the identification of wetland function and the estimation of ecosystem services derived from playa wetlands. Use of this manual by natural resource managers would provide information regarding changes in playa wetland service provisioning and inform conservation decisions

    Anthropogenic landscape change and amphibian diversity in tropical montane biodiversity hotspots: insights from satellite remote sensing in the Madagascar highlands

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    The magnitude of anthropogenic landscape change in tropical montane biodiversity hotspots and its relationship with biodiversity is a global issue that remains ‘locked-in’ in the broad narrative of tropical change in Africa. Over a montane biodiversity hotspot of Madagascar highlands (Ankaratra Massif), we conducted analysis on land cover change with Landsat satellite sensor data to identify the magnitude of change (1995–2016) and on the habitat change–amphibian diversity relationship to understand links with biodiversity. The results evidenced that 17.8% of the biodiversity hotspot experienced change in land cover in only 20 years. That pressured the already threatened forests, particularly since 2005. Of the total forest area in 1995 (2062.7 ha), 21.5% was cleared by 2016 (1618.3 ha). Changes in forest cover followed a bidirectional pattern. While in the period 1995–2005, forests expanded at a rate of 2.0% year−1 (from 2062.7 to 2524.8 ha), the area declined between 2005 and 2016 at a rate of − 4.1% year−1, fourfold the rate reported nationally for Madagascar (− 1.1% year−1). Forest-to-shrubland transitions emerged as being of increasing concern to forest integrity. We identified a significant link between habitat change and amphibian diversity, but only for species richness. Counter to expectations, no significant relationship was found between species richness and deforestation rates, and between microendemism rates and any of the habitat change variables. Species richness responded to the spatiotemporal variability in vegetation dynamics represented by the standard deviation of the Normalized Differenced Vegetation Index (NDVI_std). Species richness was strongly negatively related to NDVI_std in the short-term (R2 = 0.91, p = 0.003) and long-term (R2 = 0.69, p = 0.03), increasing where the spatiotemporal variability in NDVI was lower. The magnitude of changes in this biodiversity hotspot suggests that region-specific assessments are necessary in the context of the tropical change narrative in Africa and should consider conservation policies tailored for local conditions. Reducing deforestation and land conversion rates through a management plan codesigned with local communities is urgent. Habitat change appears to impact on amphibian diversity by altering the functional attributes of the habitat and not just by reducing habitat extent. NDVI_std seems a relevant indirect metric for monitoring such change although other biophysical attributes obtained from satellite sensor data should be integrated and explored.info:eu-repo/semantics/acceptedVersio

    SPATIAL PRIORITIZATION FOR INVASIVE PLANT MANAGEMENT

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    Invasive exotic plant species have been recognized as serious threats to ecosystems. Extensive research on invasive exotic plant species has primarily focused on the impacts, characteristics, and potential treatments. Decision tools and management models that incorporate these findings often lack input from managers and have limited use in differing invasion scenarios. Therefore, in this study, I created a scientifically-driven framework that incorporates expert input to prioritize watersheds for management within the Inner Bluegrass region of Kentucky. The widely distributed invasive exotic plant Amur honeysuckle (Lonicera maackii) was used as an example species. The framework is built around the Analytic Hierarchy Process and highlights areas in most need of invasive exotic plant management by incorporating weighted landscape variables associated with the invasion process. Results of the prioritization provide useful information for natural resource managers by aiding in the development of control strategies while also creating a valuable framework that can be adapted to various invasive exotic plant species

    Statistical and cartographic modeling of vernal pool locations: Incorporating the spatial component into ecological modeling

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    Vernal pools are small, isolated, depressions that experience cyclical periods of inundation and drying. Many species have evolved strategies to utilize the unique characteristics of vernal pools; however, their small size, seasonal nature, and isolation from other, larger water bodies, suggest increased risk of damage/loss by development. The goals of this research were to statistically determine physical predictors of vernal pool presence and, subsequently, to represent the output cartographically for use as a conservation tool. Logistic regression and Classification and Regression Tree (CART) routines were used to define important variables (slope, aspect, land use, soils, and reflectance) of 405 known vernal pools across northeastern Massachusetts. The CART models performed most favorably, achieving cartographic accuracies as high as 97% and providing a set of rules for vernal pool prediction. This combined statistical and spatial approach represents an efficient and accurate method of identifying vernal pools in Massachusetts and other, similar landscapes

    REMOTE DETECTION OF EPHEMERAL WETLANDS IN MID- ATLANTIC COASTAL PLAIN ECOREGIONS: LIDAR AND HIGH-THROUGHPUT COMPUTING

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    Ephemeral wetlands are ecologically important freshwater ecosystems that occur frequently throughout the Atlantic coastal plain ecoregions of North America. Despite the growing consensus of their importance and imperilment, these systems historically have not been a national conservation priority. They are often cryptic on the landscape and methods to detect ephemeral wetlands remotely have been ineffective at the landscape scales necessary for conservation planning and resource management. Therefore, this study fills information gaps by employing high-resolution light detection and ranging (LiDAR) data to create local relief models that elucidate small localized changes in concavity. Relief models were then processed with local indicators of spatial association (LISA) in order to automate their detection by measuring autocorrelation among model indices. Following model development and data processing, field validation of 114 predicted wetland locations was conducted using a random stratified design proportional to landcover, to measure model commission (α) and omission (β) error rates. Wetland locations were correctly predicted at 85% of visited sites with α error rate = 15% and β error rate = 5%. These results suggest that devised local relief models captured small geomorphologic changes that successfully predict ephemeral wetland boundaries in low-relief ecosystems. Small wetlands are often centers of biodiversity in forested landscapes and this analysis will facilitate their detection, the first step towards long-term management

    Condicionantes ecológicos de la distribución de anfibios en el Parque Nacional de Doñana

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    [ES] En esta tesis se analizan los requerimientos de hábitat de las especies de anfibios en el Parque Nacional de Doñana, prestando una atención especial a los aspectos metodológicos que pueden sesgar los resultados inferidos. En particular, se ha tenido en cuenta la dinámica temporal del sistema y la fiabilidad de las ausencias, una consecuencia directa de la detectabilidad imperfecta de la especie en el área. También se ha evaluado la utilidad de la teledetección en el estudio de la variación espacial y temporal de los hábitats reproductivos de los anfibios y en la elaboración de modelos estadísticos de distribución de las especies.[EN] In this thesis there are analyzed the requirements of habitat of the species of amphibians in Doñana's National Park, giving a special attention to the methodological aspects that can slant the inferred results. Especially, there has been born in mind the temporary dynamics of the system and the reliability of the absences, a direct consequence of the imperfect detectabilidad of the species in the area. Also the usefulness of the teledetección has been evaluated in the study of the spatial and temporary variation of the reproductive habitats of the amphibians and in the production of statistical models of distribution of the species
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