Delineation of Coastal Marsh Types Along the Central Texas Coast

Mitchell, M.; Ballard, Bart M.; Visser, Jenneke M.; Brasher, Michael G.; Redeker, Eric J.

doi:10.1007/s13157-014-0531-4

Cited by 3 publications

(3 citation statements)

References 17 publications

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“…Salt marshes provide habitat for rare and endangered species, prevent erosion and protect coastal areas, sequester carbon, and act as nurseries for fish and shellfish. However, projected sea level rise as a result of climate change (Melillo et al 2014;IPCC, 2014) will cause marshland to become submerged or move inland, resulting in habitat changes or loss for fish and wildlife (Mitchell et al, 2014). For these reasons, we need improved methods for assessing these changes to inform management and public policy.…”

Section: Introductionmentioning

confidence: 99%

“…However, the spatial resolution of these traditional satellite-based data sources (e.g., 15x15 meters for panchromatic Landsat ETM+), coupled with the inability to acquire these imagery "on demand" limit the land cover detail they can provide. Mitchell et al (2014) recognize the utility of higher spatial and temporal resolution imagery for more fine-scaled classifications of these landscapes, but raise the concern of costs over benefits. However, their discussion alludes to the use of more traditional remote sensing technologies (e.g., helicopters); the use of UAS-based remote sensing might dramatically reduce this cost versus benefit equation.…”

Section: Introductionmentioning

confidence: 99%

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Developing a Land Cover Classification of Salt Marshes Using Uas Time-Series Imagery and an Open Source Workflow

Myers

Schweik

Wicks

et al. 2018

Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci.

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Salt marsh ecology classification is difficult using traditional coarse resolution remote sensing techniques. Salt marshes exhibit a spatial pattern of vegetation zonation that are visually identifiable using imagery that has an improved 0.04 meter per pixel resolution. This project applies high resolution unmanned aerial system (UAS) imagery to aid in multi-temporal classification of our study area (Horseneck Beach) in Westport, Massachusetts, USA. We flew a DJI Phantom Pro 3 at low-and high-tide to capture effects the changing tide has on vegetation in an effort to predict effects of the rising sea level on saline plant species. We implement an open source software workflow using OpenDroneMap and the Semi-Automatic Classification Plugin for QGIS to create the necessary orthomosaics and to conduct vegetation classification required of this project. We compare land cover classifications using one-time-point RGB imagery to a multi-time-point (low tide, high tide) RGB image stack to investigate whether the multi-time point stack improves land cover classification accuracy. We find it does. More generally, this paper provides a model for others wishing to use low-cost UAS equipment carrying a simple low-cost RGB camera, and free and open source for geospatial (FOSS4G) tools, to develop multi-band image stacks to improve land cover classification accuracy. Further, we provide some reflections and technical notes on our experience. The approach we present here could be extended to include other image layers that UAS can provide when equipped with other sensors, such as multi-spectral (e.g., NIR, thermal), or by adding another band with photogrammetry-produced digital elevation data.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Developing a Land Cover Classification of Salt Marshes Using Uas Time-Series Imagery and an Open Source Workflow

Myers

Schweik

Wicks

et al. 2018

Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci.

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“…However, because the Western Gulf Coast population primarily occupies coastal marshes, understanding how these potential influences on populations may be affected by projected climate change is important for management of the species. From 1955 to 1992, it is estimated that the estuarine wetland area through the Texas Coastal Plain decreased by 9.5% (∼24,126 ha) and palustrine wetlands decreased by 4.3% (61,127 ha; Moulton et al ), likely causing reductions in the carrying capacity of waterfowl habitats along the Texas Gulf Coast (Mitchell et al ). Additionally, it remains unknown how environmental factors may contribute to variation in the population relative to intrinsic factors such as density dependence.…”

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confidence: 99%

Quantifying changes and influences on mottled duck density in Texas

2017

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Understanding the relative influence of environmental and intrinsic effects on populations is important for managing and conserving harvested species, especially those species inhabiting changing environments. Additionally, climate change can increase the uncertainty associated with management of species in these changing environments, making understanding factors affecting their populations even more important. Coastal ecosystems are particularly threatened by climate change; the combined effects of increasing severe weather events, sea level rise, and drought will likely have non-linear effects on coastal marsh wildlife species and their associated habitats. A species of conservation concern that persists in these coastal areas is the mottled duck (Anas fulvigula). Mottled ducks in the western Gulf Coast are approximately 50% below target abundance numbers established by the Gulf Coast Joint Venture for Texas and Louisiana, USA. Although evidence for declines in mottled duck abundance is apparent, specific causes of the decrease remain unknown. Our goals were to determine where the largest declines in mottled duck population were occurring along the system of Texas Gulf Coast National Wildlife Refuges and quantify the relative contribution of environmental and intrinsic effects on changes to relative population density. We modeled aerial survey data of mottled duck density along the Texas Gulf Coast from 1986-2015 to quantify effects of extreme weather events on an index to mottled duck density using the United States Climate Extremes Index and Palmer Drought Severity Index. Our results indicate that decreases in abundance are best described by an increase in days with extreme 1-day precipitation from June to November (hurricane season) and an increase in drought severity. Better understanding those portions of the life cycle affected by environmental conditions, and how to manage mottled duck habitat in conjunction with these events will likely be key to persistence of the species under future environmental conditions. Ó 2017 The Wildlife Society.

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