The application of Landsat imageries and mangrove vegetation index for monitoring mangrove community in Segara Anakan Lagoon, Cilacap, Central Java

Abstract

The only place for estuarine-mangroves in Java Island, Segara Anakan Lagoon, experiences the vast decline of mangrove cover. Satellite remote sensing has a critical role in monitoring that change as it allows to record vast areas over time. However, most studies tend to utilize satellite data to investigate the change of mangrove areas into other land-use types rather than identify the mangrove community’s shifting. This study utilized the mangrove vegetation index (MVI) for monitoring the changes of mangrove communities at the life-form level using satellite data. The study used multi-temporal Landsat images as it has historical systematic archive data. The threshold value of the index for each class is defined by referring to the field data. The class referred to the life-form classification consisting of mangrove trees, Nypa, and understorey. The image analysis was conducted using Google Earth Engine (GEE), while R software was used for determining threshold values through statistical analysis. The result shows that the MVI can differentiate between some life forms of mangroves, with the overall accuracy reaching 78.79% and a kappa coefficient of 0.729. Further, the multi-temporal maps showed the decline of mangrove tree areas, which the understorey and Nypa community have replaced.

Mangrove forest encroachment by Nypa frutican, Derris trifoliata, and Acanthus spp. in Segara Anakan Lagoon

“…Data preparation This study used a multi-temporal mangrove map resulting from the previous study by [4]. The maps were generated from the LANDSAT images series representing three decades of mangrove distribution within 10 years intervals, namely 1990 (t0), 2000 (t1), 2010 (t2), to 2020 (t3).…”

“…However, this study used two classes of mangrove communities: mangrove trees and Nypa-understory. Nypa and understory are integrated into a class as those have a similar distribution pattern to spread rapidly in SAL [4]- [6]. Further, Derris trifoliata as the understory species and Nypa frutican are also considered invasive species [8]- [10], [12], [13].…”

“…indicates the degradation of mangroves in SAL. Understory and Nypa frutican have been increasingly dominant in the west and central part of SAL [4]- [6]. Conversely, the mangrove trees communities such as Avicennia alba and Sonneratia caseolaris have declined within a decade (2005 -2015) [5], [6].…”

Maintaining Carbon Storage Does Not Reduce Fish Production from Mangrove-Fish Pond System: A Case Study in Coastal Area of Subang District, West Java, Indonesia

“…Avicennia marina BGB = 1.28 × D 1.17 Komiyama et al [28] Rhizophora mucronata BGB = 0.1994 × ρ 0.899 × D 2. 15 Komiyama et al [29] BGB: Below-ground biomass (kg), D: tree DBH (cm).…”

“…A previous report recorded that the highest rate of mangrove deforestation occurred in three decades before 2010, where about 40% of mangrove cover was lost [12]. Between 2009 and 2019, the loss reached approximately 182 thousand ha [13], which occurred in many regions, including coastal areas on Java Island [14,15]. The main driving factors included over-exploitation of mangrove forests and conversion of the mangrove forests into brackish water aquaculture areas [10,16].…”