scholarly journals Mangrove Phenology and Water Influences Measured with Digital Repeat Photography

2021 ◽  
Vol 13 (2) ◽  
pp. 307
Author(s):  
Veeranun Songsom ◽  
Werapong Koedsin ◽  
Raymond J. Ritchie ◽  
Alfredo Huete

The intertidal habitat of mangroves is very complex due to the dynamic roles of land and sea drivers. Knowledge of mangrove phenology can help in understanding mangrove growth cycles and their responses to climate and environmental changes. Studies of phenology based on digital repeat photography, or phenocams, have been successful in many terrestrial forests and other ecosystems, however few phenocam studies in mangrove forests showing the influence and interactions of water color and tidal water levels have been performed in sub-tropical and equatorial environments. In this study, we investigated the diurnal and seasonal patterns of an equatorial mangrove forest area at an Andaman Sea site in Phuket province, Southern Thailand, using two phenocams placed at different elevations and with different view orientations, which continuously monitored vegetation and water dynamics from July 2015 to August 2016. The aims of this study were to investigate fine-resolution, in situ mangrove forest phenology and assess the influence and interactions of water color and tidal water levels on the mangrove–water canopy signal. Diurnal and seasonal patterns of red, green, and blue chromatic coordinate (RCC, GCC, and BCC) indices were analyzed over various mangrove forest and water regions of interest (ROI). GCC signals from the water background were found to positively track diurnal water levels, while RCC signals were negatively related with tidal water levels, hence lower water levels yielded higher RCC values, reflecting brownish water colors and increased soil and mud exposure. At seasonal scales, the GCC profiles of the mangrove forest peaked in the dry season and were negatively related with the water level, however the inclusion of the water background signal dampened this relationship. We also detected a strong lunar tidal water periodicity in seasonal GCC values that was not only present in the water background, but was also detected in the mangrove–water canopy and mangrove forest phenology profiles. This suggests significant interactions between mangrove forests and their water backgrounds (color and depth), which may need to be accounted for in upscaling and coupling with satellite-based mangrove monitoring.


2021 ◽  
Author(s):  
J. Aaron Hogan ◽  
Edward Castañeda-Moya ◽  
Lukas Lamb-Wotton ◽  
Christopher Baraloto

AbstractPhotosynthesis is an essential process to mangrove forest carbon cycling, which plays a critical role in the global carbon cycle. We investigated how differences in mangrove island micro-elevation (i.e., habitat) affect tree physiology in a scrub mangrove forests of the southeastern Everglades. We measured leaf gas exchange rates of scrub Rhizophora mangle trees monthly during 2019, hypothesizing that CO2 assimilation (Anet) and stomatal conductance (gsw) would decline with increases in water level and salinity, with larger differences at mangrove islands edges than centers, where inundation and salt stress are greatest. Water levels varied between 0 and 60 cm, rising during the wet season (May-October) relative to the dry season (November-April). Porewater salinity ranged from 15 to 30 ppt, being higher at mangrove island edges compared to centers. Anet maximized at 15.1 µmol m-2 s-1, and gsw was typically <0.2 mol m-2 s-1, both of which were greater in the dry than the wet season and greater at mangrove island centers than edges. After accounting for season and habitat, water level had a positive effect on Anet in both seasons, but no effect on gsw. Similarly, porewater salinity had a slightly positive marginal effect on Anet but a negligible effect on gsw Our findings suggest that water levels drive variation in Anet more than salinity in Everglades scrub mangroves, while also constraining Anet more than gsw, and that the interaction between permanent flooding and habitat varies with season as physiological stress is alleviated at higher-elevation mangrove island center habitats in the dry season. Additionally, habitat heterogeneity leads to differences in nutrient and water acquisition and use between trees growing in island centers versus edges, creating distinct physiological controls on leaf physiology and photosynthesis which could ultimately affect carbon flux dynamics of scrub mangrove forests across the Everglades landscape.



Author(s):  
Roger R Tabalessy

Coastal areas can either meet the human needs or give great contribution to the development. However, rapid infrastrural development in Sorong, west Papua, has been followed by high demand for mangrove timber and caused mangrove forest degradation due to exploitation. This exploitation could also result from high economic value of the mangrove timber. This study was done to analyze the economic value of mangrove wood utilized by the people to support the development process in Sorong. This study used primary data obtained through interviews and the economic value calculation of mangrove forests. It found that Sorong had mangrove economic value of IDR 165,197,833, 491. Wilayah pesisir selain dapat memenuhi kebutuhan hidup manusia juga memberikan kontribusi yang besar bagi pembangunan. Cepatnya pembangunan infrastruktur di Kota Sorong diikuti pula dengan tingginya permintaan akan kayu mangrove dan menyebabkan terjadinya degradasi hutan mangrove akibat eksploitasi. Eksploitasi ini disebabkan juga akibat kayu mangrove memiliki nilai ekonomi. Penelitian yang dilakukan ini bertujuan untuk menganalisis nilai ekonomi kayu mangrove yang dimanfaatkan oleh masyarakat Kota Sorong dalam proses menunjang pembangunan. Penelitian ini menggunakkan data primer yang diperoleh melalui hasil wawancara dan perhitungan nilai ekonomi hutan mangrove. Hasil penelitian ini menunjukkan nilai ekonomi ekosistem hutan mangrove yang berada di Kota Sorong adalah Rp165.197.833.491.



Forests ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 637
Author(s):  
Huong Thi Thuy Nguyen ◽  
Giles E. S. Hardy ◽  
Tuat Van Le ◽  
Huy Quoc Nguyen ◽  
Hoang Huy Nguyen ◽  
...  

Mangrove forests can ameliorate the impacts of typhoons and storms, but their extent is threatened by coastal development. The northern coast of Vietnam is especially vulnerable as typhoons frequently hit it during the monsoon season. However, temporal change information in mangrove cover distribution in this region is incomplete. Therefore, this study was undertaken to detect change in the spatial distribution of mangroves in Thanh Hoa and Nghe An provinces and identify reasons for the cover change. Landsat satellite images from 1973 to 2020 were analyzed using the NDVI method combined with visual interpretation to detect mangrove area change. Six LULC classes were categorized: mangrove forest, other forests, aquaculture, other land use, mudflat, and water. The mangrove cover in Nghe An province was estimated to be 66.5 ha in 1973 and increased to 323.0 ha in 2020. Mangrove cover in Thanh Hoa province was 366.1 ha in 1973, decreased to 61.7 ha in 1995, and rose to 791.1 ha in 2020. Aquaculture was the main reason for the loss of mangroves in both provinces. Overall, the percentage of mangrove loss from aquaculture was 42.5% for Nghe An province and 60.1% for Thanh Hoa province. Mangrove restoration efforts have contributed significantly to mangrove cover, with more than 1300 ha being planted by 2020. This study reveals that improving mangrove restoration success remains a challenge for these provinces, and further refinement of engineering techniques is needed to improve restoration outcomes.



2020 ◽  
Vol 13 (1) ◽  
pp. 52
Author(s):  
Win Sithu Maung ◽  
Jun Sasaki

In this study, we examined the natural recovery of mangroves in abandoned shrimp ponds located in the Wunbaik Mangrove Forest (WMF) in Myanmar using artificial neural network (ANN) classification and a change detection approach with Sentinel-2 satellite images. In 2020, we conducted various experiments related to mangrove classification by tuning input features and hyper-parameters. The selected ANN model was used with a transfer learning approach to predict the mangrove distribution in 2015. Changes were detected using classification results from 2015 and 2020. Naturally recovering mangroves were identified by extracting the change detection results of three abandoned shrimp ponds selected during field investigation. The proposed method yielded an overall accuracy of 95.98%, a kappa coefficient of 0.92, mangrove and non-mangrove precisions of 0.95 and 0.98, respectively, recalls of 0.96, and F1 scores of 0.96 for the 2020 classification. For the 2015 prediction, transfer learning improved model performance, resulting in an overall accuracy of 97.20%, a kappa coefficient of 0.94, mangrove and non-mangrove precisions of 0.98 and 0.96, respectively, recalls of 0.98 and 0.97, and F1 scores of 0.96. The change detection results showed that mangrove forests in the WMF slightly decreased between 2015 and 2020. Naturally recovering mangroves were detected at approximately 50% of each abandoned site within a short abandonment period. This study demonstrates that the ANN method using Sentinel-2 imagery and topographic and canopy height data can produce reliable results for mangrove classification. The natural recovery of mangroves presents a valuable opportunity for mangrove rehabilitation at human-disturbed sites in the WMF.



2016 ◽  
Vol 13 (17) ◽  
pp. 5085-5102 ◽  
Author(s):  
Caitlin E. Moore ◽  
Tim Brown ◽  
Trevor F. Keenan ◽  
Remko A. Duursma ◽  
Albert I. J. M. van Dijk ◽  
...  

Abstract. Phenology is the study of periodic biological occurrences and can provide important insights into the influence of climatic variability and change on ecosystems. Understanding Australia's vegetation phenology is a challenge due to its diverse range of ecosystems, from savannas and tropical rainforests to temperate eucalypt woodlands, semi-arid scrublands, and alpine grasslands. These ecosystems exhibit marked differences in seasonal patterns of canopy development and plant life-cycle events, much of which deviates from the predictable seasonal phenological pulse of temperate deciduous and boreal biomes. Many Australian ecosystems are subject to irregular events (i.e. drought, flooding, cyclones, and fire) that can alter ecosystem composition, structure, and functioning just as much as seasonal change. We show how satellite remote sensing and ground-based digital repeat photography (i.e. phenocams) can be used to improve understanding of phenology in Australian ecosystems. First, we examine temporal variation in phenology on the continental scale using the enhanced vegetation index (EVI), calculated from MODerate resolution Imaging Spectroradiometer (MODIS) data. Spatial gradients are revealed, ranging from regions with pronounced seasonality in canopy development (i.e. tropical savannas) to regions where seasonal variation is minimal (i.e. tropical rainforests) or high but irregular (i.e. arid ecosystems). Next, we use time series colour information extracted from phenocam imagery to illustrate a range of phenological signals in four contrasting Australian ecosystems. These include greening and senescing events in tropical savannas and temperate eucalypt understorey, as well as strong seasonal dynamics of individual trees in a seemingly static evergreen rainforest. We also demonstrate how phenology links with ecosystem gross primary productivity (from eddy covariance) and discuss why these processes are linked in some ecosystems but not others. We conclude that phenocams have the potential to greatly improve the current understanding of Australian ecosystems. To facilitate the sharing of this information, we have formed the Australian Phenocam Network (http://phenocam.org.au/).



2015 ◽  
Vol 105 (1) ◽  
pp. 35-40 ◽  
Author(s):  
Diva S. Tavares ◽  
Rafaela C. Maia ◽  
Cristina Rocha-Barreira ◽  
Helena Matthews-Cascon

Leaf litter represents a food source to many organisms that may directly contribute to organic matter decomposition. In addition, the physical presence of these vegetal detritus contributes for the modification of some environmental areas and produce microhabitats that may act as a refuge against predators and desiccation for many animals. The pulmonate gastropod Melampus coffeus (Linnaeus, 1758) (Ellobiidae) is a very common specie in Atlantic Coast mangrove forests and feeds on fallen mangrove leaves. It was hypothesized that the spatial distribution of Melampus coffeus is directly affected by mangrove leaf litter biomass deposition. Thus, this research aimed at evaluating the spatial distribution of these gastropods in relation to the biomass of mangrove leaf litter through a twelve-month period. The study area was established in the middle estuary of Pacoti River, state of Ceará, Brazil where two adjacent zones with different topographic profiles were determined. Samples of Melampus coffeus and leaf litter were collected monthly, throughout a year, from the mangrove ground surface. The results indicated that the presence of twigs in mangrove litter favor the occupation by smaller individuals of M. coffeus, probably because smaller individuals are more susceptible to predator attacks and desiccation than larger ones, and twigs and branches may provide a safe microhabitat.



2017 ◽  
Vol 8 (1) ◽  
pp. 63-68
Author(s):  
Omo Rusdiana ◽  
Fajar Alif Sam Pangestu

The area of mangrove forests in Indonesia is currently only spanning as much as 3.4 milion acres, so there is a need for the participation of the government and community to maintain its sustainability. South Halmahera is the district with the largest mangrove area in the North Maluku Province. One of the mangrove areas in the District of South Halmahera is located at Sayoang Village, East Bacan Subdistrict Up until its eleventh founding anniversary, this district have never conducted an inventorizing of its mangroves, both ecological and social studies in the field of public. This study aims to analyze the compotition of mangrove species in Sayoang Village, East Bacan Subdistrict, South Halmahera, and identify the knowledge of surrounding communities of mangrove areas as protected areas. Data were retrieved using sampling method with applications terraced paths, and analyzed by calculating its important value index (INP) and its index value diversity (IVD). The public social data were taken using in-depth interviews and questionnaires. Results obtained from this study show that the mangrove forest in Sayoang Village, East Bacan District, Halmahera, consists of major mangrove species with as many as eleven species belonging to families Rhizophoraceae, Sonneratiaceae, Avicenniaceae, Meliaceae and Myrtaceae, and as many as three species of minor mangrove belonging to families of Loranthaceae, Acanthaceae, and Pteridaceae. The mangrove's species diversity and richness is and low, but it has high evenness. The results showed that 60% of total respondents know the benefit of mangrove as fish habitat, while for mangrove area as conserving areas, 50% of total respondent don't know the status of the area. The cutting problems happened in mangrove areas, 90% of total respondent know the activity and 85% of total respondent think that the logging activities in mangrove area is still allowed. The management activity of mangrove area in Sayoang village hasn't been conducted, either by the community or by local Dinas Kehutanan, and 53% of total respondent still wishing the mangrove can give more benefit economically.Key words: Mangrove forest, mangrove protected areas, community knowledge



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



2021 ◽  
Vol 748 (1) ◽  
pp. 012017
Author(s):  
E Wahyuni ◽  
Zulhafandi ◽  
Hendris ◽  
Jarin

Abstract Mangrove forests are natural resources in coastal areas that have an important role in terms of social, economic and ecological aspects. However, the utilization of the mangrove ecosystem makes it vulnerable to damage. This study aims to determine the level of public knowledge of the economic, ecological benefits and damage that happened to mangrove areas in Tarakan City. The scoring method was used to determine the total score or the total score of the respondents’ answers, which amount to 50 people. that the community’s knowledge of the economic benefits of mangrove forests was categorized as know for the benefits of mangroves as firewood, mangrove areas as a place for settlement, mangroves as a place to get fish and mangrove benefits as aquaculture areas with total scores of 226, 200, 232,230 respectively. However, the level of community knowledge about the benefits of mangroves as a medicinal ingredient obtained a total score of 164, which means the level of community knowledge was in the doubtful category. While the level of community knowledge of the ecological benefits of mangrove forests as coastline guards, sea wave barriers, sea wind protectors, and animal breeding sites were included in the category of “Know” with a total score of 228, 224, 234, 240 respectively, but the level of knowledge The community regarding the benefits of mangroves that can manage household waste was in the “doubtful” category with a total score of 128. The community was aware of the damage to mangrove forest ecosystems caused by garbage, logging / mangroves, expanding aquaculture, settlements and increasing population. with a total score of 234,232, 210,228 and 200 levels of knowledge, respectively, which are included in the “Know” category.



2019 ◽  
Vol 7 (1) ◽  
Author(s):  
. Wahyuti ◽  
Iskandar A M ◽  
Gusti Hardiansyah

The community role is needed in the implementation of mangrove forest tourism management, especially in planning activities. The role of the community is the involvement of community itself in the development activities, both in the planning, implementation, evaluation, and the stages of esnjoying the results of the development itself. The purpose in this descriptive qualitative study was to determine the role of community in managing mangrove forest tourism in the subdistrict of Sukadana of Kayong Utara regency. Data collection techniques consist of observation, interviews, and documentation. While the analysis was carried out with descriptive analysis technique. The results of this study indicate that the role of of the sejahtera village community in managing mangrove forest tourism is limited to the maintenance of natural resources, maintenance of cleanliness and nursery of mangrove forests. Due to mangrove forest management is still fully managed by The Gunung Palung National Park Agency, the role of the community in the management of tourism in mangrove forests is still low. Therefore, the involvement of the surrounding community needs special attention and other related parties in utilizing mangrove forest tourism.Keyword: community role, mangrove forest, themanagement of mangrove tourism



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