Facing the peat CO2 threat: digital mapping of Indonesian peatlands—a proposed methodology and its application

Abstract

Purpose We conducted this project to develop a feasible method for mapping tropical peat lands of Bengkalis Island-as a test site-in Indonesia. Materials and methods The method based on limited availability of field measurements and a wide range of remotely sensed spatial datasets like radar elevation product, MODIS, and Landsat imageries. We applied land use category based sampling to extend existing field data of peat thickness. New peat thickness data was collected by boring and simultaneous electrical resistivity tomography (ERT). Based on remotely sensed and field data sets, peat maps were compiled by simulated spatial annealing. Peat map statistics were derived after 500 runs including mean, median, minimum, maximum, and percentile values. Results and discussion The resulted maps represent the limiting values of expected peat thickness using 90% confidence level. Results showed that ERT is suitable for determining peat layer thickness. Using independent samples, we found that peat thickness predictions tend to overestimate peat thickness by ca. 2 m in general. Conclusions According to predictions, the peat volume of Bengkalis Island is estimated to be in the range of 3.28-3.58 km 3 .

Machine learning for digital soil mapping: Applications, challenges and suggested solutions

“…This has been further considered by Stojanova et al (2013) for both categorical and quantitative mapping of ecological variables. Illés et al (2019) applied polygonal declustering technique to spatially clustered samples by assigning weights on the units based on Voronoi's area proportion.…”

Mapping peat thickness and carbon stock of a degraded peatland in West Sumatra, Indonesia

“…The challenge of mapping such an area is that peat thickness had a weak relationship with the covariates, and spatial interpolation provided the best estimates. Past studies on peatlands in Indonesia found a strong correlation between elevation and peat thickness (Illés et al, 2019;Rudiyanto et al, 2016Rudiyanto et al, , 2018. This lack of a strong relationship with elevation and distance to rivers could be because of the nature of peatland in West Sumatra and intense human disturbances.…”

“…In addition, method based on land cover was used to map peatland in remote area such as the Central Congo Basin (Crezee et al, 2022). DSM can help generate accurate peatlands maps (Minasny et al, 2019) and has been applied to map peat thickness in Kalimantan and the east coast of Sumatra with prominent dome-shaped peats (Crowson et al, 2019;Illés et al, 2019;Rudiyanto et al, 2016Rudiyanto et al, , 2018. However, DSM application to assess the level of peatland degradation in the tropics is still limited.…”

Evaluation of change in the peat soil properties affected by different fire severities

“…Digital mapping of the tropical peatlands of Bengkalis Island has been proposed using the electrical resistivity tomography to determine peat layer thickness (Illés et al 2019). Sadly, many peatlands are threatened by the human activities for the development of the plantation areas.…”