scholarly journals Continuous Wavelet Analysis of Leaf Reflectance Improves Classification Accuracy of Mangrove Species

2019 ◽  
Vol 11 (3) ◽  
pp. 254 ◽  
Author(s):  
Yi Xu ◽  
Junjie Wang ◽  
Anquan Xia ◽  
Kangyong Zhang ◽  
Xuanyan Dong ◽  
...  

Due to continuous degradation of mangrove forests, the accurate monitoring of spatial distribution and species composition of mangroves is essential for restoration, conservation and management of coastal ecosystems. With leaf hyperspectral reflectance, this study aimed to explore the potential of continuous wavelet analysis (CWA) combined with different sample subset partition (stratified random sampling (STRAT), Kennard-Stone sampling algorithm (KS), and sample subset partition based on joint X-Y distances (SPXY)) and feature extraction methods (principal component analysis (PCA), successive projections algorithm (SPA), and vegetation index (VI)) in mangrove species classification. A total of 301 mangrove leaf samples with four species (Avicennia marina, Bruguiera gymnorrhiza, Kandelia obovate and Aegiceras corniculatum) were collected across six different regions. The smoothed reflectance (Smth) and first derivative reflectance (Der) spectra were subjected to CWA using different wavelet scales, and a total of 270 random forest classification models were established and compared. Among the 120 models with CWA of Smth, 88.3% of models increased the overall accuracy (OA) values with an improvement of 0.2–28.6% compared to the model with the Smth spectra; among the 120 models with CWA of Der, 25.8% of models increased the OA values with an improvement of 0.1–11.4% compared to the model with the Der spectra. The model with CWA of Der at the scale of 23 coupling with STRAT and SPA achieved the best classification result (OA = 98.0%), while the best model with Smth and Der alone had OA values of 86.3% and 93.0%, respectively. Moreover, the models using STRAT outperformed those using KS and SPXY, and the models using PCA and SPA had better performances than those using VIs. We have concluded that CWA with suitable scales holds great potential in improving the classification accuracy of mangrove species, and that STRAT combined with the PCA or SPA method is also recommended to improve classification performance. These results may lay the foundation for further studies with UAV-acquired or satellite hyperspectral data, and the encouraging performance of CWA for mangrove species classification can also be extended to other plant species.

2019 ◽  
Vol 7 (1) ◽  
Author(s):  
Syahrul Muharamsyah ◽  
M Sofwan Anwari ◽  
Hafiz Ardian

Mangrove forests are unique ecosystems that have ecological, biological and socio-economic functions. The function of mangrove forests on the environment is very important especially in the coastal and oceanic regions. Mangrove forests providers of wood, leaves as raw material for medicines, and natural dye. This study aims to inventory the diversity of species of mangrove vegetation in Mendalok Village, Sungai Kunyit Subdistrict, Mempawah Regency. The benefits of this study are to provide the data on mangrove forest vegetation as basic data for local government and related agencies in efforts to protect and preserve mangrove forests in Mendalok Village, Sungai Kunyit Subdistrict, Mempawah Regency. Inventory the tree in mangrove forest used a line with measured 200 meters. There are 6 lines and the distance between the lines as far as 100 meters. The lines of observation are placed by purposive sampling. The results of research found 11 types of species and consisted of 6 genera. The genera are Avicennia, Bruguiera, Ceriops, Rhizophora, Soneratia and Xylocarpus. The species found were Avicennia alba, Avicennia marina, Bruguiera cylindrica, Bruguiera gymnorrhiza, Bruguiera parviflora, Ceriops decandra, Rhizophora apiculata, Rhizophora mucronata, Rhizophora stylosa, Sonneratia caseolaris, Xylocarpus mollucensis. Diversity of mangrove species in Mendalok Village, Sungai Kunyit Subdistrict, Mempawah Regency was high and should be maintained for conservation and ecotourism area. Keywords : conservation, ecotourism, mangrove, Mendalok Village


2020 ◽  
Vol 7 (2) ◽  
pp. 70
Author(s):  
Wahyudi Andrito ◽  
Syafruddin Nasution ◽  
Efriyeldi Efriyeldi

 Mangrove ecosystems are one of three important ecosystems in the coastal areas that supports global warming mitigation efforts. The existence of mangrove forests is needed to reduce the increased CO2 concentrations in the atmosphere. However, the rise of the water temperatures and sea levels indirectly affects the presence and condition of mangrove forests in coastal areas. The purpose of this study is to determine the condition of the mangrove community on the East Coast of Jemaja, Anambas Archipelagoes Regency. The survey method  was used in this study and a series survey activities were conducted for a quadrant transect with a size of 10m by 10m in December 2019 - March 2020.The result shown that the five mangrove species were identified, such as Rhizophora apiculata, R. mucronata, Bruguiera gymnorrhiza, Ceriops tagal and Xylocarpus granatum. R. apiculata dominates with an important value index of 123.12%. While, the average density of mangroves and saplings in the study area was 3155 ± 785 individuals/ha and the average canopy cover was 84.03 ± 3.11%. With this finding, it can be concluded that the condition of mangroves in the East Coast of Jemaja is very dense and still in a good condition.


2020 ◽  
Vol 3 (1) ◽  
pp. 29-37
Author(s):  
Paulinus ◽  
Mubarak Mubarak ◽  
Efriyeldi Efriyeldi

The study was conducted in May-June 2019 on Rangsang Island. This study aims to determine the effect of mangrove forests on coastline found on the island of Rangsang in Riau Province. The sampling location was determined by purposive sampling, namely 3 station points, namely Segomeng Village, Tanjung Kedabu Village, and Sungai Gayung Kiri Village. Landsat image data analyzed at the Oceanographic Physics Laboratory of the Department of Marine Sciences, Faculty of Fisheries and Maritime Affairs, University of Riau. To find out the area of ​​mangroves using Landsad 5 TM satellite imagery and Landsat 8 OLI Tirs imagery and analyzed using Er Mapper Software, Envi 4.5 and Arcgis 10.3. Calculation of the structure of the mangrove community is carried out using the line plot plot method. The results of the analysis of the vast landsat image of mangroves in the coastal areas of Rangsang Island in 1997, 2002, 2007, 2013, 2019 were respectively 11,093 ha, 10,807 ha, 10,393 ha, 10,121 ha and 9,971 ha. Changes in the coastline indicate the occurrence of abrasion and accretion, where the highest abrasion occurs at station three with an average of -7.6 m/year and accretion occurs at station one with an average of 2.68 m / year. Mangrove density at station one is 2266.7 ind / ha and at station two that is 1466.7 ind / ha. Mangrove species found were Rhizophora apiculata, Rhizophora mucronata, Avicennia alba, Sonneratia ovata, Bruguiera gymnorrhiza, and Xylocarpus granatum.


2019 ◽  
Vol 11 (21) ◽  
pp. 2479 ◽  
Author(s):  
Huiying Li ◽  
Mingming Jia ◽  
Rong Zhang ◽  
Yongxing Ren ◽  
Xin Wen

Information on mangrove species composition and distribution is key to studying functions of mangrove ecosystems and securing sustainable mangrove conservation. Even though remote sensing technology is developing rapidly currently, mapping mangrove forests at the species level based on freely accessible images is still a great challenge. This study built a Sentinel-2 normalized difference vegetation index (NDVI) time series (from 2017-01-01 to 2018-12-31) to represent phenological trajectories of mangrove species and then demonstrated the feasibility of phenology-based mangrove species classification using the random forest algorithm in the Google Earth Engine platform. It was found that (i) in Zhangjiang estuary, the phenological trajectories (NDVI time series) of different mangrove species have great differences; (ii) the overall accuracy and Kappa confidence of the classification map is 84% and 0.84, respectively; and (iii) Months in late winter and early spring play critical roles in mangrove species mapping. This is the first study to use phonological signatures in discriminating mangrove species. The methodology presented can be used as a practical guideline for the mapping of mangrove or other vegetation species in other regions. However, future work should pay attention to various phenological trajectories of mangrove species in different locations.


2020 ◽  
Vol 17 (12) ◽  
pp. 2150-2154 ◽  
Author(s):  
Zhi He ◽  
Qian Shi ◽  
Kai Liu ◽  
Jingjing Cao ◽  
Wen Zhan ◽  
...  

REINWARDTIA ◽  
2014 ◽  
Vol 14 (1) ◽  
pp. 171
Author(s):  
Suhardjono Prawiroatmodjo ◽  
Kuswata Kartawinata

We studied  the floristic compostion and structure of mangrove forests and mangrove species distribution at the Raja Ampat Regency, West Papua  We sampled the forests using (10x10 m) quadrats to record trees and saplings  laid out contiguously along 9 transects of 60 – 450 m long,  stretching perpendicularly from the coastlines or riverbanks to the landward borders. Seedlings were sampled using a 1x1 m subplot nested in each quadrat.  The transects were established on the islands of  Batanta (6), Salawati  (2). and Waigeo (1).  Within quadrats and transects we recorded 17 mangrove species of trees with density of 768 stems/ha and basal area of  37.82 m2/ha and tree height of  10 – 30 m.   Two species possessed  the highest importance value  (IV) , frequency, density and basal area  i.e. Rhizophora apiculata (IV=168.06 %) and  Bruguiera gymnorrhiza (IV=67.18).  They also showed the highest similarity in their distribution,  indicating highest degree of association.  The mangrove at Raja Ampat may, therefore,  be designated as the Rhizophora apiculata-Bruguiera gymnorrhiza Association. Other species with highest degree of distributional similarities but with low densities, basal areas and importance values were Barringtonia racemosa, Excoecaria agallocha, Hibiscus tiliaceus, Inocarpus fagifera,  Lumnitzera littorea and Sterculia shillinglawii,  of which four of them are not  true mangrove species, usually growing on less saline and more solid soils. The floristic composition of the transects in the three islands showed relatively high similarities of about 70 % and at higher similarities the transects in Batanta Island formed four groups, Salawati Island two groups and Waigeo Island one group.The Bray-Curtis polar ordination  resulted in four groups  of transects, which were related to the habitat  conditions and the length of the transects. Species diversity in the islands was very low, where the  Shannon diversity index  ranged  from  0.19 to 0.64 giving  the average  of 0.42. Rhizophora apiculata and Bruguiera gymnorrhiza  were gregenerating well and in the future they will remain dominant.  The mangrove forests of the Raja Ampat Islands by any means should be maintained as green belts and  protected from all kinds of destruction and should be made into conservation areas in order to sustain its ability to provide ecological services  and non-destructive economic benefits.


2019 ◽  
pp. 67-75
Author(s):  
Teofanes Patindol ◽  
Eulito Casas

This study reflects the present status of Tacloban City mangrove vegetation and would be useful for mangrove restoration program. Surveys of mangrove forests in Tacloban City were conducted from October to November 2017 in 12 selected sites. Quadrat method was used to assess the species composition and stand structure of the canopy layer, representing seaward, middle and landward zones. The mangrove forests in Tacloban City contain 23 mangrove species belonging to 12 families and 15 genera. Rhizophoraceae and Acanthaceae are the most dominating families. As per IUCN report, among the 23 species, 4 were recognized as threatened. These include the Endangered Camptostemon philippinensis, the Vulnerable Avicennia rumpiana and the Near Threatened Aegiceras floridum and Ceriops decandra. Rhizophora Apiculata is the most abundant species, followed by Sonneratia alba. Other abundant species are Avicennia officinalis, Avicennia marina and Rhizophora mucronata. The least abundant are Bruguiera gymnorrhiza, Camptostemon philippinensis and Xylocarpus granatum. The canopy layer is composed of small-sized trees with an average tree density of 1,678 per ha and stem density of 3,133 per ha. The average height and diameter are 6.15m and 8.95cm, respectively. Mangrove diversity is generally low. Shannon index of diversity value ranges from 0.762 to 1.132, with an average value of 0.914. Understory is characterized by few species of regenerants, low density and low species diversity.


Check List ◽  
2011 ◽  
Vol 7 (3) ◽  
pp. 253 ◽  
Author(s):  
Prabakaran Nehru ◽  
Paramasivam Balasubramanian

Mangrove habitats are crucial for maintaining the biodiversity of coastal ecosystem. Climatic change, sea level rise and anthropogenic pressures are the major threats to mangrove forests. The Nicobar Islands comprised one of the pristine mangrove stands in India. The mega earthquake of >9 M and subsequent tsunami during 2004 caused destruction of over 70% of mangrove vegetation in Nicobar Islands. The present study was carried out in the Central Nicobar Group of Islands (Camorta, Nancowry, Katchall and Trinkat), where tsunami has entirely wiped out the mangrove vegetation. Re-colonization started on its own course. We enumerated nine species of mangrove plants and 30 species of mangrove associates from the surveyed locations. Lumnitzera racemosa has been recorded for the first time from the study area. Rhizophora mucronata and Bruguiera gymnorrhiza were the common pioneer mangrove species. Long-term monitoring of re-colonization process will help us in understanding succession of mangrove forests. 


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