Mangrove Rehabilitation Programs Research Articles

MAPPING AND CHANGE ANALYSIS IN MANGROVE FOREST BY USING LANDSAT IMAGERY

Mangrove is located in the tropical and subtropical regions and brings good services for native people. Mangrove in the world has been lost with a rapid rate. Therefore, monitoring a spatiotemporal distribution of mangrove is thus critical for natural resource management. This research objectives were: (i) to map the current extent of mangrove in the West and Central Africa and in the Sundarbans delta, and (ii) to identify change of mangrove using Landsat data. The data were processed through four main steps: (1) data pre-processing including atmospheric correction and image normalization, (2) image classification using supervised classification approach, (3) accuracy assessment for the classification results, and (4) change detection analysis. Validation was made by comparing the classification results with the ground reference data, which yielded satisfactory agreement with overall accuracy 84.1% and Kappa coefficient of 0.74 in the West and Central Africa and 83.0% and 0.73 in the Sundarbans, respectively. The result shows that mangrove areas have changed significantly. In the West and Central Africa, mangrove loss from 1988 to 2014 was approximately 16.9%, and only 2.5% was recovered or newly planted at the same time, while the overall change of mangrove in the Sundarbans increased approximately by 900 km<sup>2</sup> of total mangrove area. Mangrove declined due to deforestation, natural catastrophes deforestation and mangrove rehabilitation programs. The overall efforts in this study demonstrated the effectiveness of the proposed method used for investigating spatiotemporal changes of mangrove and the results could provide planners with invaluable quantitative information for sustainable management of mangrove ecosystems in these regions.

MAPPING AND CHANGE ANALYSIS IN MANGROVE FOREST BY USING LANDSAT IMAGERY

Abstract. Mangrove is located in the tropical and subtropical regions and brings good services for native people. Mangrove in the world has been lost with a rapid rate. Therefore, monitoring a spatiotemporal distribution of mangrove is thus critical for natural resource management. This research objectives were: (i) to map the current extent of mangrove in the West and Central Africa and in the Sundarbans delta, and (ii) to identify change of mangrove using Landsat data. The data were processed through four main steps: (1) data pre-processing including atmospheric correction and image normalization, (2) image classification using supervised classification approach, (3) accuracy assessment for the classification results, and (4) change detection analysis. Validation was made by comparing the classification results with the ground reference data, which yielded satisfactory agreement with overall accuracy 84.1% and Kappa coefficient of 0.74 in the West and Central Africa and 83.0% and 0.73 in the Sundarbans, respectively. The result shows that mangrove areas have changed significantly. In the West and Central Africa, mangrove loss from 1988 to 2014 was approximately 16.9%, and only 2.5% was recovered or newly planted at the same time, while the overall change of mangrove in the Sundarbans increased approximately by 900 km2 of total mangrove area. Mangrove declined due to deforestation, natural catastrophes deforestation and mangrove rehabilitation programs. The overall efforts in this study demonstrated the effectiveness of the proposed method used for investigating spatiotemporal changes of mangrove and the results could provide planners with invaluable quantitative information for sustainable management of mangrove ecosystems in these regions.

Vegetation and soil characteristics as indicators of restoration trajectories in restored mangroves

We investigated the restoration trajectories in vegetation and soil parameters of monospecific Rhizophora mucronata stands planted 6, 8, 10, 11, 12, 17, 18, and 50 years ago (restored system). We tested the hypothesis that the changes in vegetation characteristics, with progressing mangrove age, are related to the changes in soil characteristics. The vegetation and soil parameters were compared across this restoration sequence using a reference system comprising mature, natural mangrove stands of unknown age. Rapid increases in leaf area index and aboveground biomass, and declines in tree density and size (in terms of tree diameter and height) occurred with increasing stand age. Soil organic matter, total nitrogen, and soil redox potential increased, and soil temperature decreased as stands aged. These patterns tended to stabilize at approximately the 11th year, indicating the probable age that restoration plots tend toward forest maturity. The time for the restored systems to reach forest maturity, attaining characteristics similar to the reference system, is estimated at 25 years, which is relatively slow compared to forest regeneration trajectories estimated for natural mangroves. Our study describes the trajectory patterns for planted mangroves, which are important for the assessment of both the progress and success of mangrove rehabilitation programs.

Contribution of organic material from white mangrove (Avicennia marina) to evaluate mangrove ecosystem management: Case Study of Labuhan Maringgai, East Lampung

Abstract. Yulma, Adiwilaga EM, Wardiatno Y. 2013. Contribution of organic material from white mangrove (Avicennia marina) to evaluate mangrove ecosystem management: Case Study of Labuhan Maringgai, East Lampung. Bonorowo Wetlands 3: 12-29. The purpose of this study was to determine the potential contribution of organic matter (C, N, and P) of mangrove forest litter production in Labuhan Maringgai, East Lampung, to the marine environment, as well as evaluate the mangrove rehabilitation program conducted by the Lampung Mangrove Center program of the University of Lampung, Bandar Lampung. Lampung Mangrove Center (LMC) provides litter productivity of 4.53 g/m2/day with the most significant contributor from leaf litter and twigs, while flowers and fruit are not found. The dry weight of the remaining mangrove leaf litter on day 56 ranged between 5-2.5 g. LMC has the potential production of organic material that can be used litter amounted to 0.76164 GC/m2/day; 0.00628 GN/m2/day; 0.00331 GP/m2/day. Mangrove rehabilitation involving three parties, including the Government of East Lampung District, University of Lampung, and the community, is very effective in conserving mangrove forests in LMC within 1,000 ha of mangrove ranges.

Comparing Mangrove Forest Management in Hai Phong City, Vietnam towards Sustainable Aquaculture

This study examined the driving forces of mangrove change and compared mangrove forest management mechanisms in coastal districts in Hai Phong city, Vietnam. Survey data was used to ascertain the driving forces of mangrove change. The market price approach was used to analyze how local people responded to mangrove forest conservation. The results indicated that implementation of mangrove management instigated by the authorities, community or local people has affected mangrove change. The main driving factor of mangrove degradation in Hai Phong was over expansion of shrimp aquaculture. In Trang Cat commune, Hai An district, the average size of shrimp ponds where expansion was controlled by the local people, was 12.81 hectares. This number was over 53 times higher than in Bang La commune, Do Son district, which was mainly converted from salt ponds. Extensive aquaculture in the former case was the main method of farming which provides low net benefits while the improved shrimp culture in the latter case brings higher net benefits. Mangrove plantation programs funded by the Japanese organizations helped the poor guarantee their lives in Bang La. In Trang Cat, the poorer households would like to participate in mangrove conservation more than richer families. Nevertheless, the upper and rich families in Bang La engaged in mangrove plantation programs did more extensively than the middle and the poor did. Mangrove rehabilitation programs in Bang La have been successfully conducted on account of community-based forest management in cooperation with local authorities. The failure to convert shrimp ponds from mangrove forests was clearly recorded in Trang Cat. This commune needed to replant mangrove in abandoned shrimp ponds and follow the mangrove management mechanism in Bang La.

Breakdown of mangrove leaf litter in a replanted mangrove forest in Kalpitiya, Puttlam lagoon

The mangroves in Puttlam Lagoon were exploited by coastal communities for various purposes such as for fuel wood, for construction timber fencing and for shrimp farms. In order to protect and expand the mangrove vegetation the Turtle Conservation Project (TCP) has initiated a mangrove rehabilitation program in Puttlam Lagoon. By this project Rhizopora mucronata was replanted as it is the dominant species in the area. The present study was conducted with a view to assess the decomposition rate of R. mucronata leaves under replanted conditions. Decomposition of the selected sp leaves was studied in situ using litter bags in 5 years old replanted sites in Kalpitiya, Puttlam lagoon. Four sites were selected for the study as Eththala, Palakuda, Palliwasathurai and Anawasala in Kalpitiya. Litter samples were placed in 0.5 x 0.5 m litter bags and placed on the plantation floor to assess the litter decomposition rate. During 123 days decomposition experiment in each site, Eththala(83.95%), Palakuda(71.99%), Palliwasathurai(82.51%) and Anawasala (92.10 %) weight loss of fresh mass was recorded. According to the p-value (0.452) there were no significant differences in dry weight mass loss among these 5 year old replanted sites. A single exponential decay model was used to describe the rate of decomposition in each site. According to the results obtained from the exponential model rate of decomposition constant per day was 0.02, 0.01, 0.01 and 0.02 in Anawasala, Palakuda, Palliwasthurai and Eththala respectively. There was no significant difference of rate of decomposition constant in each site. The time in days required for the loss of half of the initial dry mass was 34, 67, 49 and 49 in Anawasala, Palakuda, Palliwasthurai and Eththala respectively. In order to calculate the maximum decomposition limit for litter decomposition for a period of one year, time spent in data collection data was not sufficient. Therefore, it was forecasted the limit value according to the pattern of decomposition and trend analysis with Minitab 14. The maximum decomposition values for Rhizophora mucronata replanted sites were 99.99%.

Mangrove Rehabilitation Program in Southern Thailand with Japanese Volunteers and Local People

Mangrove Rehabilitation Program in Southern Thailand with Japanese Volunteers and Local People

Monitoring mangrove forest dynamics of the Sundarbans in Bangladesh and India using multi-temporal satellite data from 1973 to 2000

Mangrove forests in many parts of the world are declining at an alarming rate—possibly even more rapidly than inland tropical forests. The rate and causes of such changes are not known. The forests themselves are dynamic in nature and are undergoing constant changes due to both natural and anthropogenic forces. Our research objective was to monitor deforestation and degradation arising from both natural and anthropogenic forces. We analyzed multi-temporal satellite data from 1970s, 1990s, and 2000s using supervised classification approach. Our spatio-temporal analysis shows that despite having the highest population density in the world in its periphery, areal extent of the mangrove forest of the Sundarbans has not changed significantly (approximately 1.2%) in the last ∼25 years. The forest is however constantly changing due to erosion, aggradation, deforestation and mangrove rehabilitation programs. The net forest area increased by 1.4% from the 1970s to 1990 and decreased by 2.5% from 1990 to 2000. The change is insignificant in the context of classification errors and the dynamic nature of mangrove forests. This is an excellent example of the co-existence of humans with terrestrial and aquatic plant and animal life. The strong commitment of governments under various protection measures such as forest reserves, wildlife sanctuaries, national parks, and international designations, is believed to be responsible for keeping this forest relatively intact (at least in terms of area). While the measured net loss of mangrove forest is not that high, the change matrix shows that turnover due to erosion, aggradation, reforestation and deforestation was much greater than net change. The forest is under threat from natural and anthropogenic forces leading to forest degradation, primarily due to top-dying disease and over-exploitation of forest resources.

Early growth of seven mangrove species planted at different elevations in a Thai estuary

This study aimed to determine the effect of elevation on survival and growth of mangrove seedlings during the establishment period. Seven typical mangrove species, Rhizophora mucronata Poir, R. apiculata Bl., Bruguiera cylindrica (L.) Bl., Ceriops tagal (Pirr.) C.B. Rob., Sonneratia alba J. Sm., Avicennia officinalis L. and Xylocarpus granatum Koenig were planted at various topographic sites in an intertidal zone of Phang Nga province, southern Thailand. These six bare areas included two that were abandoned after tin mining and four gap areas in natural habitats in June 1998. The experimental plots were on a slope and showed a maximal elevation difference of 1.8 m. The plots were naturally submerged with 2–3% saline water twice a day. Salinity, pH and the concentrations of several ions in the soil water were similar in all the plots. Survival and growth performance of seedlings were measured every 6 months. Many seedlings of B. cylindrica, C. tagal and X. granatum planted at lower elevations died with a year. R. mucronata and S. alba survived even at the lowest elevations, but showed changes in growth rate in response to topography. Thus, early growth of the seven mangrove species at different elevations differed and showed increasing tolerance to higher tidal inundations in the order: R. mucronata, S. alba, R. apiculata, A. officinalis, C. tagal, B. cylindrica and X. granatum. These findings provide guideline information for appropriate species selection in a mangrove rehabilitation program.