scholarly journals Optimal and robust vegetation mapping in complex environments using multiple satellite imagery: Application to mangroves in Southeast Asia

2021 ◽  
Vol 99 ◽  
pp. 102320
Author(s):  
Han Xiao ◽  
Fenzhen Su ◽  
Dongjie Fu ◽  
Vincent Lyne ◽  
Gaohuan Liu ◽  
...  
Keyword(s):  
Southeast Asia ◽  
Satellite Imagery ◽  
Vegetation Mapping ◽  
Complex Environments

scholarly journals Change in tropical forest cover of Southeast Asia from 1990 to 2010

2013 ◽  
Vol 10 (8) ◽  
pp. 12625-12653 ◽  
Author(s):  
H.-J. Stibig ◽  
F. Achard ◽  
S. Carboni ◽  
R. Raši ◽  
J. Miettinen
Keyword(s):  
Southeast Asia ◽  
Satellite Imagery ◽  
Forest Cover ◽  
Satellite Image ◽  
Image Interpretation ◽  
Selective Logging ◽  
Automated Classification ◽  
Forest Cover Change ◽  
Forest Change ◽  
The One

Abstract. The study assesses the extent and trends of forest cover in Southeast Asia for the period 1990–2000–2010 and provides an overview on the main drivers of forest cover change. A systematic sample of 418 sites (10 km × 10 km size) located at the one-degree geographical confluence points and covered with satellite imagery of 30 m resolution is used for the assessment. Techniques of image segmentation and automated classification are combined with visual satellite image interpretation and quality control, involving forestry experts from Southeast Asian countries. The accuracy of our results is assessed through an independent consistency assessment, performed from a subsample of 1572 mapping units and resulting in an overall agreement of > 85% for the general differentiation of forest cover vs. non-forest cover. The total forest cover of Southeast Asia is estimated at 268 Mha in 1990, dropping to 236 Mha in 2010, with annual change rates of 1.75 Mha (~0.67% and 1.45 Mha (~0.59%) for the periods 1990–2000 and 2000–2010, respectively. The vast majority of forest cover loss (~2/3 for 2000–2010) occurred in insular Southeast Asia. Combining the change patterns visible from satellite imagery with the output of an expert consultation on the main drivers of forest change highlights the high pressure on the region's remaining forests. The conversion of forest cover to cash crop plantations (e.g. oil palm) is ranked as the dominant driver of forest change in Southeast Asia, followed by selective logging and the establishment of tree plantations.

scholarly journals Shining Light on Data-Poor Coastal Fisheries

2021 ◽  
Vol 7 ◽  
Author(s):  
Owen M. Exeter ◽  
Thaung Htut ◽  
Christopher R. Kerry ◽  
Maung Maung Kyi ◽  
Me'ira Mizrahi ◽  
...  
Keyword(s):  
Southeast Asia ◽  
Satellite Imagery ◽  
Low Income ◽  
Marine Ecosystem ◽  
Small Scale ◽  
Marine Biodiversity ◽  
Artificial Light ◽  
Coastal Fisheries ◽  
Fishing Vessels ◽  
Biomass Removal

Coastal fisheries provide livelihoods and sustenance for millions of people globally but are often poorly documented. Data scarcity, particularly relating to spatio-temporal trends in catch and effort, compounds wider issues of governance capacity. This can hinder the implementation and effectiveness of spatial tools for fisheries management or conservation. This issue is acute in developing and low-income regions with many small-scale inshore fisheries and high marine biodiversity, such as Southeast Asia. As a result, fleets often operate unmonitored with implications for target and non-target species populations and the wider marine ecosystem. Novel and cost-effective approaches to obtain fisheries data are required to monitor these activities and help inform sustainable fishery and marine ecosystem management. One such example is the detection and numeration of fishing vessels that use artificial light to attract catch with nighttime satellite imagery. Here we test the efficiency and application value of nighttime satellite imagery, in combination with landings data and GPS tracked vessels, to estimate the footprint and biomass removal of an inshore purse seine fishery operating within a region of high biodiversity in Myanmar. By quantifying the number of remotely sensed vessel detections per month, adjusted for error by the GPS tracked vessels, we can extrapolate data from fisher logbooks to provide fine-scale spatiotemporal estimates of the fishery's effort, value and biomass removal. Estimates reveal local landings of nearly 9,000 mt worth close to $4 million USD annually. This approach details how remote sensed and in situ collected data can be applied to other fleets using artificial light to attract catch, notably inshore fisheries of Southeast Asia, whilst also providing a much-needed baseline understanding of a data-poor fishery's spatiotemporal activity, biomass removal, catch composition and landing of vulnerable species.

scholarly journals Change in tropical forest cover of Southeast Asia from 1990 to 2010

2014 ◽  
Vol 11 (2) ◽  
pp. 247-258 ◽  
Author(s):  
H.-J. Stibig ◽  
F. Achard ◽  
S. Carboni ◽  
R. Raši ◽  
J. Miettinen
Keyword(s):  
Southeast Asia ◽  
Satellite Imagery ◽  
Forest Cover ◽  
Satellite Image ◽  
Image Interpretation ◽  
Important Change ◽  
Automated Classification ◽  
Natural Forests ◽  
Forest Cover Change ◽  
Forest Change

Abstract. The study assesses the extent and trends of forest cover in Southeast Asia for the periods 1990–2000 and 2000–2010 and provides an overview on the main causes of forest cover change. A systematic sample of 418 sites (10 km × 10 km size) located at the one-degree geographical confluence points and covered with satellite imagery of 30 m resolution is used for the assessment. Techniques of image segmentation and automated classification are combined with visual satellite image interpretation and quality control, involving forestry experts from Southeast Asian countries. The accuracy of our results is assessed through an independent consistency assessment, performed from a subsample of 1572 mapping units and resulting in an overall agreement of >85% for the general differentiation of forest cover versus non-forest cover. The total forest cover of Southeast Asia is estimated at 268 Mha in 1990, dropping to 236 Mha in 2010, with annual change rates of 1.75 Mha (∼0.67%) and 1.45 Mha (∼0.59%) for the periods 1990–2000 and 2000–2010, respectively. The vast majority of forest cover loss (∼2 / 3 for 2000–2010) occurred in insular Southeast Asia. Complementing our quantitative results by indicative information on patterns and on processes of forest change, obtained from the screening of satellite imagery and through expert consultation, respectively, confirms the conversion of forest to cash crops plantations (including oil palm) as the main cause of forest loss in Southeast Asia. Logging and the replacement of natural forests by forest plantations are two further important change processes in the region.

A method for vegetation stratification using scale-related, vegetation-enhanced satellite imagery

Bothalia ◽  
1986 ◽  
Vol 16 (2) ◽  
pp. 263-268 ◽  
Author(s):  
R. H. Westfall ◽  
O. G. Malan
Keyword(s):  
Satellite Imagery ◽  
Vegetation Mapping

A method for visual vegetation stratification and pattern refinement, using scale-related, vegetation-enhanced satellite imagery, is described. The method simplifies colour assignment, facilitates accurate vegetation mapping and could lead to balanced floristic classifications.

Sign in / Sign up

Export Citation Format

Share Document