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Mangroves in Myanmar
Abstract
The mangrove extent in Myanmar, according to the most recent forest resources assessment in 2020, has been estimated as 1.12 million acres. Among three main tracts of mangroves—Rakhine coastline, Ayeyarwady delta, and Tanintharyi coastline—the mangroves in the Tanintharyi coastline have now turned into the largest areal extent despite the fact that the Ayeyarwady delta had the largest in the past. With a large share of the Bay of Bengal Large Marine Ecosystem, coastal and delta ecosystems including mangroves, coral reefs, seagrass beds, beaches, and dunes largely flourish throughout the Myanmar coastline. In this context, the Tanintharyi coast showed the highest species diversity of mangrove flora while the least species diversity was observed in the Ayeyarwady delta. Provided that a total of ten prominent provisioning, regulating, supporting, and cultural services were considered, fishery nursery and habitat has shown its highest value in the mangrove ecosystem services, followed by coastal protection. In particular for the latter services of coastal protection, local communities and their tremendous properties were saved, and lifelong lessons were learned during the deadliest impacts of Cyclone Nargis 2008. The mangrove ecosystems in Myanmar, however, have been alarmingly threatened due to overexploitation of fuelwood and charcoal production; mangrove conversion to other land uses such as rice fields, shrimp farming, and salt pans; coastal and delta development with human settlement; improper revenue collection on mangrove products in forest management; and climate change and natural disasters. One of the major measures to tackle the existing issues and problems is community-based forest management, called “community forestry (CF)” in mangroves that is a remarkable initiative since 1995 in the aspects of partnership, participation, and decentralization in managing the mangroves in Myanmar. In connection with the findings on the CF study regarding the regeneration of some resilient mangrove species after the impact of Cyclone Nargis, coppice management would be supportive and beneficial to local communities in their own mangrove management. The case study in the chapter demonstrated as well that most of the local stakeholders had fairly sufficient awareness and attitudes to enable active participation in mangrove restoration although there were slight differences between the different stakeholders. In particular, poorer attitudes were observed in some migrant communities compared to the settled communities. In developing a mangrove management strategy, inclusiveness should, therefore, be one of the key take-home messages by prioritizing the subsistence needs of the local people plus economic benefits.
... Furthermore, the Yangon Region bottleneck area is close to the Dedaye, which is a potentially important dispersal route connecting the eastern section of the Ayeyaewady mangroves and the western section of the Yangon mangroves (Fig. 3b). However, there are considerable losses of mangrove cover in Ayeyarwady and the adjacent Yangon Region due to pressures from human use, and damage from natural disasters in recent decades (De Alban et al., 2020;Aung, 2022). Illegal logging within protected areas, including the Meinmahla Kyun wildlife sanctuary (Wang, 2016), has resulted in sparse mangrove trees, indicating that deforestation extends beyond unprotected regions (Webb et al., 2014). ...
Landscape-level conservation strategies are needed to protect the saltwater crocodile population and habitats in Myanmar. Identifying the remaining habitats and movement corridors is essential due to population decline across coastal regions and insufficient habitat coverage, even within protected areas. This study predicts the distribution of habitats and creates low-resistance corridors that facilitate movement across the landscape. Occurrence dataset encompassing a 20-year period (1999-2019) was used incorporating records gathered from the Global Biodiversity Information Facility-GBIF, crocodile counting reports from the Meinmahla Kyun wildlife sanctuary of Myanmar, and recent spotlight and camera-trap surveys. Using landscape connectivity tools, structural compositions of habitat classes were determined, and habitat patches were delineated to simulate the least-cost corridor and dispersal pathways. Two patches in Rakhine, two in Ayeyarwady and Yangon, one in Mon, and two in Tanintharyi, were identified that include 1247 km 2 of core suitable habitat areas. The Ayeyarwady Delta exhibits a plethora of suitable habitats, while the Rakhine and Tanintharyi regions have higher marginal habitats that are largely unprotected. Only 12 % of the extent of occurrence of saltwater crocodiles are suitable habitats with a high potential for occupancy. Habitats are highly fragmented and four bottlenecks are identified to assist population connectivity in those fragmented patches. Despite notable challenges in ensuring connectivity to restore populations across the habitat patches, we highlighted connectivity as the foundation for establishing an ecological network of Myanmar's coastal habitats, leveraging the saltwater crocodile as an umbrella species for the region's coastal wetlands, and identifying key areas for enhanced protection.
Background
Mangrove forests are highly productive ecosystems that serve as biodiversity points, containing many organisations, contributing to carbon storage, improving water quality and providing ecosystem goods and services to improve local means of subsistence. These resilient ecosystems are characterised by their morphological modification and their particular respiratory structures (pneumatophores), which allow them to proliferate in salt-rich environments. Mangroves play a crucial role in maintaining invertebrate and fishery resources, providing shelter and nutrients to a diverse range of species. However, mangrove ecosystems are threatened by anthropogenic activities such as the extraction of building materials, firewood, crushing plants and salt manufacturing, resulting in the disintegration of ecosystems and the loss of inhabitants. This study aimed to determine the abundance and diversity of macro-benthic invertebrates on the different parts (roots, stems and leaves) of common mangrove species of the Mbegani coast, along the Indian Ocean using a completely randomised design.
Results
The sampling was done using a 1 m ² quadrat focussed on the three mangrove parts, viz. roots, stems and leaves. The results showed that the highest percentage of macro-invertebrates were recorded on Bruguera gymnorhiza (66.8%), followed by Avicennia marina (20.8%) and the least were Ceriops tagal (12.4%), such variation differed significantly between the three mangrove species across the selected plots ( F (2,524) = 5.71, p = 0.035). The stems (54.4%) inhabited a large number of macro-invertebrates, followed by roots (32.8%) and the least were leaves (12.8%), which varied significantly between the three mangrove parts sampled across the selected mangrove species ( F (2,524) = 7.25; p = 0.008). The majority of macro-invertebrates were planktonic feeders stuck on stems or herbivores shuttling between the roots and leaves of the plants. Macro-invertebrates recorded on Bruguiera gymnorhiza were more diverse than those found in C. tagal . The findings emphasise the importance of macro-invertebrates in the ecological balance of mangrove ecosystems.
Conclusion
The study concludes that mangroves in the Mbegani ecosystem have a high potential for biodiversity and are important for the coastal community and the ecosystem of the Bagamoyo District. The results contribute to coastal resources management programmes and future surveillance activities.
Fauna and Flora International Inc initiated an ecological and botanical assessment of Meinmahla Kyun Wildlife Sanctuary (MKWS) and its adjacent western and eastern banks over the course of two weeks in May 2016. MKWS is essentially an extensive mangrove forested island with many channels in the Ayeyarwady (or Irrawaddy) region of Myanmar. Following the field survey, three post-trip validation of all the sampled plants (photographs) was conducted using the herbarium materials kept at the Singapore Botanic Gardens herbarium (SING), and the main reference consulted for Myanmar plants was provided by Kress et al (2003) (A checklist of the trees, shrubs, herbs, and climbers of Myanmar, Smithsonian Institution, US National Herbarium vol 45, 1-590). In addition, various post-trip research and analyses (floristic, ecological, geographical and agricultural) were carried out to support a future five-year biodiversity and livelihood management strategy for MKWS and its adjacent riverbanks communities.
This manuscript describes the biogeography and composition of mangroves in Myanmar. It underlines the significant and ongoing decline of mangrove coverage, the importance to protect these ecosystems, and their roles for critically endangered species of flora and fauna. Reasons for mangrove habitat loss are analysed. The monetary value of mangrove ecosystem services for coastal people has been estimated. UNESCO Biosphere Reserves and Ramsar sites have been suggested as best options for the future conservation and management of Myanmar’s mangroves. Developing community-based protected areas and forest management within the framework of the Man and the Biosphere Programme would cater for most of the management options that also involve local communities.
In a survey of the Myeik Archipelago, we documented seven seagrass species in the southern region. Three seagrass species (Cymodocea rotundata, Enhalus acoroides, and Halophila ovalis) have previously been reported in the Myeik Archipelago; three species (Halodule pinifolia, Halodule uninervis, Syringodium isoetifolium) are new reports for the archipelago; and one species (Thalassia hemprichii) is a new report for Myanmar.
The restoration of mangroves has received a lot of attention world wide for several reasons. Firstly, the long ignored ecological and environmental values of mangrove forests have been documented for many mangrove areas in the world. Secondly, there is a high subsistence dependence on natural resources from mangrove forests. In addition, large losses of man- groves have occurred throughout the world leading to coastal erosion, decline of fishery resources and other environmental consequences, some of which in need of urgent attention. Finally, governments throughout the world are showing commitments towards sustainable use of mangrove areas. This paper outlines the activi- ties of mangrove restoration and management around the world with particular emphasis on Eastern Africa. As noted here, extensive research has been carried out on the ecology, structure and functioning of the man- grove ecosystem. However, the findings have not been interpreted in a management framework, thus mangrove forests around the world continue to be over-exploited, converted to aquaculture ponds, and polluted. We strongly argue that links between research and sustain- able management of mangrove ecosystems should be established.
Tropical mangrove forests are characterized by clear zonation along a tidal gradient, and it has been supposed that the zonation is primarily controlled by soil factors. However, effects of disturbance on mangrove forests are still not well understood and may play an important role on the vegetation patterns and forest dynamics in some forest formations. In this study, the pattern of disturbance regime and its effects on regeneration of tropical mangrove forests along a tidal gradient were investigated in Ranong, Thailand. We established one or two 0.5ha plots in four vegetation zones, i.e. Sonneratia alba–Avicennia alba zone, Rhizophora apiculata zone, Ra – Bruguiera gymnorrhiza zone, Ceriops tagal–Xylocarpus spp. zone. Gap size (percentage gap area to total study area and individual gap size) was the largest in Sa–Aa zone which is located on the most seaward fringe, and it declined from seaward to inland. Canopy trees of S. alba and A. alba had stunted trunks and showed low tree density. On the contrary, canopy dominants in the other three inland zones, e.g. R. apiculata, B. gymnorrhiza, and Xylocarpus spp., had slender trunks and showed high tree density. Accordingly, differences in disturbance regime among the four zones were resulted from the forest structural features of each zone. Disturbance regime matched with regeneration strategies of canopy dominants. Seedlings and saplings of S. alba and A. alba, which need sunny condition for their growth, were abundant in gaps than in understorey. By contrast, R. apiculata, B. gymnorrhiza, and Xylocarpus spp., which can tolerate less light than S. alba and A. alba, had greater seedling and sapling density under closed canopy than gaps. Many large gaps may enhance the abundance of S. alba and A. alba in Sa–Aa zone, and a few small gaps may prevent the light demanding species to establish and grow in the other inland zones. Correspondence of disturbance regime and regeneration strategies (e.g. light requirement) of canopy dominants may contribute to the maintenance of the present species composition in each of the vegetation zones.
Although hurricane disturbance is a natural occurrence in mangrove forests, the effect of widespread human alterations on
the resiliency of estuarine habitats is unknown. The resiliency of mangrove forests in southwest Florida to the 2004 hurricane
season was evaluated by determining the immediate response of mangroves to a catastrophic hurricane in areas with restricted
and unrestricted tidal connections. The landfall of Hurricane Charley, a category 4 storm, left pronounced disturbances to
mangrove forests on southwest Florida barrier islands. A significant and negative relationship between canopy loss and distance
from the eyewall was observed. While a species-specific response to the hurricane was expected, no significant differences
were found among species in the size of severely impacted trees. In the region farthest from the eyewall, increases in canopy
density indicated that refoliation and recovery occurred relatively quickly. There were no increases or decreases in canopy
density in regions closer to the eyewall where there were complete losses of crown structures. In pre-hurricane surveys, plots
located in areas of management concern (i.e., restricted connection) had significantly lower stem diameter at breast height
and higher stem densities than plots with unrestricted connection. These differences partially dictated the severity of effect
from the hurricane. There were also significantly lower red mangrove (Rhizophora mangle) seedling densities in plots with restricted connections. These observations suggest that delays in forest recovery are possible
in severely impacted areas if either the delivery of propagules or the production of seedlings is reduced by habitat fragmentation.
Mangrove forests along many tropical coastlines are frequently andseverely damaged by hurricanes. The ability of mangrove forests to regeneratefollowing hurricanes has been noted, but changes that occur in vegetationfollowing disturbance by hurricane winds and storm tides have not been studied.We measured changes in plant community structure and environmental variables intwo fringe mangrove forests in south Florida, USA that experienced high windvelocities and storm tides associated with Hurricane Andrew (August1992). Loss of the forest canopy stimulated regeneration via seedlinggrowth and recruitment, as well as resprouting of some trees that survived thehurricane. Initial regeneration differed among species in both forests:Rhizophora mangle L. regenerated primarily via growth ofseedlings present at the time of the hurricane (i.e., release of advancerecruits), but many trees of Avicennia germinans(L.) Stearn and Laguncularia racemosa Gaertn.f.resprouted profusely from dormant epicormic buds. In one forest, which wasformerly dominated by Laguncularia, high densities ofRhizophora seedlings survived the hurricane and grew toform dense stands of saplings and small trees ofRhizophora. In the other forest, there were lowerdensitiesof surviving Rhizophora seedlings (possibly due tohigher storm tide), and extensive bare areas that were colonized byAvicennia, Laguncularia, andherbaceous species. This forest, predominantly Rhizophoraat the time of the hurricane, now contains stands of saplings and small treesofall three species, interspersed with patches dominated by herbaceous plants.These findings indicate that moderately damaged fringe forests may regenerateprimarily via release of Rhizophora advance recruits,leading to single-species stands. In severely damaged forests, seedlingrecruitment may be more important and lead to mixed-species stands.Regeneration of mangrove forests following hurricanes can involve differentpathways produced by complex interactions between resprouting capability,seedling survival, post-hurricane seedling recruitment, and colonizationby herbaceous vegetation. These differences in relative importance ofregeneration pathways, which may result in post-hurricane forestsdifferent from their pre-hurricane structure, suggest that models forregeneration of mangrove forests will be more complex than directregeneration models proposed for other tropical forests whereregeneration after hurricanes is dominated by resprouting.
This review assesses the degree of resilience of mangrove forests to large, infrequent disturbance (tsunamis) and their role in coastal protection, and to chronic disturbance events (climate change) and the future of mangroves in the face of global change. From a geological perspective, mangroves come and go at considerable speed with the current distribution of forests a legacy of the Holocene, having undergone almost chronic disturbance as a result of fluctuations in sea-level. Mangroves have demonstrated considerable resilience over timescales commensurate with shoreline evolution. This notion is supported by evidence that soil accretion rates in mangrove forests are currently keeping pace with mean sea-level rise. Further support for their resilience comes from patterns of recovery from natural disturbances (storms, hurricanes) which coupled with key life history traits, suggest pioneer-phase characteristics. Stand composition and forest structure are the result of a complex interplay of physiological tolerances and competitive interactions leading to a mosaic of interrupted or arrested succession sequences, in response to physical/chemical gradients and landform changes. The extent to which some or all of these factors come into play depends on the frequency, intensity, size, and duration of the disturbance. Mangroves may in certain circumstances offer limited protection from tsunamis; some models using realistic forest variables suggest significant reduction in tsunami wave flow pressure for forests at least 100 m in width. The magnitude of energy absorption strongly depends on tree density, stem and root diameter, shore slope, bathymetry, spectral characteristics of incident waves, and tidal stage upon entering the forest. The ultimate disturbance, climate change, may lead to a maximum global loss of 10–15% of mangrove forest, but must be considered of secondary importance compared with current average annual rates of 1–2% deforestation. A large reservoir of below-ground nutrients, rapid rates of nutrient flux and microbial decomposition, complex and highly efficient biotic controls, self-design and redundancy of keystone species, and numerous feedbacks, all contribute to mangrove resilience to various types of disturbance.
There is growing research interest in the ethnobiology, socio-economics and management of mangrove forests. Coastal residents who use mangroves and their resources may have considerable botanical and ecological knowledgeable about these forests. A wide variety of forest products are harvested in mangroves, especially wood for fuel and construction, tannins and medicines. Although there are exceptions, mangrove forest products are typically harvested in a small-scale and selective manner, with harvesting efforts and impacts concentrated in stands that are closer to settlements and easiest to access (by land or by sea). Mangroves support diverse, local fisheries, and also provide critical nursery habitat and marine productivity which support wider commercial fisheries. These forests also provide valuable ecosystem services that benefit coastal communities, including coastal land stabilization and storm protection. The overlapping of marine and terrestrial resources in mangroves creates tenure ambiguities that complicate management and may induce conflict between competing interests. Mangroves have been cut and cleared extensively to make way for brackish water aquaculture and infrastructure development. More attention is now given to managing remaining forests sustainably and to restoring those degraded from past use. Recent advances in remotely sensed, geo-spatial monitoring provide opportunities for researchers and planners to better understand and improve the management of these unique forested wetlands.
The world over, public institutions appear to be responding to the calls voiced by activists, development practitioners and
progressive thinkers for greater public involvement in making the decisions that matter and holding governments to account
for following through on their commitments. Yet what exactly ‘participation’ means to these different actors can vary enormously.
This article explores some of the meanings and practices associated with participation, in theory and in practice. It suggests
that it is vital to pay closer attention to who is participating, in what and for whose benefit. Vagueness about what participation
means may have helped the promise of public involvement gain purchase, but it may be time for more of what Cohen and Uphoff
term ‘clarity through specificity’ if the call for more participation is to realize its democratizing promise.
Significance
This study quantifies the proximate drivers (i.e., replacement land uses) of mangrove deforestation across Southeast Asia between 2000 and 2012. Mangrove forests in the region were lost at an average rate of 0.18% per year. Aquaculture was a major pressure on mangrove systems during this period, but its dominance was lower than expected, contrary to popular development narratives. Rice agriculture has been a major driver of mangrove loss in Myanmar, and oil palm expansion is a key but under-recognized threat in Malaysia and Indonesia. The threat of oil palm to mangroves is likely to increase in the future as new frontiers open up in Papua, Indonesia. Future research and policy responses must consider the diversity of drivers of mangrove deforestation.
The impacts of four different management systems on diversity of ground-foraging ants were examined to assess potential for conservation of biological diversity in human-influenced agricultural or agroforestry systems. Using a variety of indices, diversity was measured along a gradient of anthropogenically disturbed habitats. The gradient, in terms of increasing levels of disturbance, ranged from primary rain forest, abandoned cacao plantations, productive cacao plantations, to banana plantations. The primary forest and abandoned cacao plantations were situated in a reserve and the productive cacao plantations, and banana plantations were located on privately owned land within 35 km of the reserve in the Sarapiqui Valley of Costa Rica. To sample ground-foraging ants, we placed tuna baits along the ground in each habitat. Although tuna baits attract a generalist assemblage of ants that may be better able to adapt to more disturbed sites, diversity of this community was significantly reduced with increased disturbance. Ant diversity was not different for forest and abandoned cacao sites except in terms of evenness, with the forest having a more even distribution of species. Forest and abandoned cacao sites were significantly more diverse than both productive cacao and banana plantations. The latter two did not differ significantly from each other in terms of diversity, but there was considerable variability within each of these habitat types. The results of this study suggest that conservation of diversity may be possible in a @'mosaic@' of different land uses, but further studies, such as those addressing the importance of scale and nearby source populations, are necessary before management practices can be implemented.
We review historical, current, and projected future impacts of four classes of anthropogenic disturbance-extraction, pollution, reclamation, and changing climate-on Caribbean mangrove ecosystems (mangal). These disturbances occur, respectively, at increasing spatial and temporal scales, and require increasing recovery time. Small-scale selective extraction has little system-wide effect, but regeneration is slow even on single hectare clear-cuts due to rapid soil acidification. Petroleum is the primary pollutant of Caribbean mangal, and results in tree defoliation, stand death, and loss of associated sessile and mobile animal species. Hydrocarbons persist in mangrove sediments for decades, and are correlated with increasing seedling mutation rates. Chemical, industrial, and urban wastes are associated with increased heavy metal content of seedlings, stand die-back, reduced system-wide species richness, and higher incidence of Vibrio spp. (shellfish poisoning). Mangal has been reclaimed for urbanization, industrialization, and increasingly, for tourism. Overall, the region is losing mangrove forests at ≈1 percent per yr, although the rate is much faster on the Caribbean mainland (≈1.7% yr1) than it is on the islands (≈0.2% yr-1). The region's fisheries are declining at a similar rate, as most commercial shellfish and finfish use mangal for nurseries and/or refugia. Few Caribbean states have legislation or enforcement capabilities to protect or manage mangal, although at least 11 international treaties and conventions could be applied to conserve or sustainably use these forests. These treaties may protect riverine and basin mangal, but are likely to be moot with respect to fringing mangal, which may vanish as a consequence of global climate change. Growth enhancements of mangroves resulting from increasing atmospheric CO2 probably will not compensate for negative effects of concomitant rises in regional sea level.
The estuarine crocodile Crocodylus porosus was formerly abundant in coastal regions of Myanmar, but is now known principally from the lower Ayeyarwady Delta. We conducted a survey during January 1999 to assess quantitatively the status of crocodile populations in protected areas of the lower delta. Spotlight counts were conducted along 275.4 km of waterways. Sixty-one crocodiles (50 juveniles, 4 subadults, 2 adults and 5 eyeshines) were observed in the Meinmahla Kyun Wildlife Sanctuary (MKWS), and the total population was estimated to be less than 100. The Kadônkani and Pyindaye Reserved Forests (RF) apparently no longer support viable populations. Although crocodiles remain critically endangered in the region, a comparison with survey data from 1980 suggests localized recovery is occurring in MKWS. Population declines are attributed to a combination of commercial skin hunting, habitat loss, drowning in fishing nets and over-collection of living animals to supply crocodile farms. A programme of law enforcement, habitat protection and head-starting juveniles is necessary to ensure the continued survival of estuarine crocodiles in the Ayeyarwady Delta.
Mangroves in the Ayeyarwady Mega Delta of Myanmar are crucial for the ecology, society and economy of this country. At the beginning of May 2008, a severe cyclonic storm, Cyclone Nargis, struck the Ayeyarwady mangroves. Since that time, the present long-term study has been exploring the dynamics of post-cyclone mangrove vegetation. Every year since the 2008 cyclone, a census has been taken of 60 permanent plots (each measuring 10 m × 10 m) in six mangrove communities in order to predict trends in their long-term recovery. Each selected mangrove community was dominated by either Avicennia officinalis, Bruguiera sexangula, Excoecaria agallocha, Heritiera fomes, Rhizophora apiculata, or Sonneratia caseolaris. Mortality among the Rhizophoraceae group, including B. sexangula and R. apiculata adult individuals, was more than 90%, whereas for other species belonging to the non-Rhizophoraceae group, it was less than 20%. Based on the 5-year assessment, the mangroves showed considerable resilience after the catastrophic cyclone disturbance. However, the recovery potential of specific species varied. In particular, communities where R. apiculata dominated demonstrated slow recovery processes. The reasons for the vulnerability of this species of Rhizophora to cyclone disturbance is assumed to be the result of three indirect post-cyclone consequences: high mortality caused by limited sprouting ability after wind-induced disturbance; erosion that occurred in the stressful habitat on riverbank mud flats with frequent tidal inundation; and delayed phenology after the catastrophic disturbance. The attempt to generalise the recovery rate of mangroves based on the crown closure of the six dominant mangrove communities explored in this study showed a recovery rate of 61.06% during the 4 years after Cyclone Nargis. The demonstration of these patterns and processes among the most dominant mangrove species after the cyclone disturbance should therefore provide reliable information to forest managers, ecologists and local people, helping them make management decisions regarding measures for mangrove restoration.
The objective of this study was to compare the variation in the soil seed banks and the aboveground vegetation in relation to three habitats, i.e., swamp forests, grassland and sand dunes within the Sundarbans mangrove forests of Bangladesh. We collected vegetation data (species and their percentage cover) by using quadrat sampling: 10m×10m for swamp forests and 5m×5m for grassland and sand dunes. We estimated the density of viable seeds of species in the seed bank by counting germinants from soil cores in a germination chamber. Species richness and composition of both aboveground vegetation and the soil seed banks differed significantly among habitats. We identified a total of 23 species from the soil seed bank. Of these, two were true mangrove species and the remaining were non-mangrove species, including halophytic grasses, herbs and mangrove associate species. Our results confirm that mangrove species do not possess a persistent soil seed bank. The presence of high-density non-mangrove and associated mangrove species in the soil seed bank implies that after frequent catastrophic disturbances which limit incoming propagules from adjacent forest stand, large canopy gaps can easily become invaded by non-mangrove and mangrove associate species. This would result in the formation of a cover of non-mangrove species and cryptic ecological degradation in mangrove habitats. We suggest that forest managers should actively consider gap plantations with mangrove species in the large canopy gaps created after catastrophic disturbances to counteract the invasion of non-mangrove species and cryptic ecological degradation.
The International Union for Conservation of Nature and Natural Resources Red List considers Batagur baska regionally extinct in Myanmar owing to the paucity of recent records. We conducted field surveys in coastal regions of Myanmar during 2004 and verified the occurrence of small populations of B. baska at scattered localities in Mon State, and Tanintharyi and Ayeyarwady Divisions. We attribute the continued persistence of these populations to a combination of local religious beliefs that discourage the capture of turtles and areas of armed conflict between government forces and Mon insurgents where fishermen can venture only at great personal risk.
The aim of this research is to analyze the situation of mangroves in Myanmar, including their formation and their economic and ecological importance. Economic importance includes fisheries, fuel-wood, charcoal production, construction materials and medicine, while ecological importance includes shoreline stabilization, protection from wind and storms, coastal ecosystem stability and biodiversity protection. Myanmar's coastal areas were in good condition until 30 years ago. However, population increase and political instability have caused environmental and economic damage and threaten recovery. Awareness of the importance of the biodiversity of the coastal ecosystem and its endangered situation has led to the implementation of measures to ensure sustainable development and conservation.
A quantitative study was conducted in 1998 to investigate differences in perception, knowledge, awareness, and attitude with regard to environmental problems between educated and community groups and to identify human-dimension factors to improve public perception, knowledge, awareness, and attitude in relation to global environmental conservation concerns in developing countries. Educated and community groups in Jakarta were interviewed, and data obtained from a total of 537 males aged 30-49 years were analyzed. The data were evaluated by the chi-squared test and logistic regression was applied after factor analysis. The results show that: (1) The perception, knowledge, awareness, and attitude of educated subjects in regard to regional and global environmental problems were much better than those of subjects in the community group; (2) The highest 'yes' response in the community group was in regard to perception of AIDS (82.9%). Few subjects in the community group knew the effects and the cause or source of environmental problems, however, they were well informed about AIDS (86.4% for effects and 93.9% for cause or source). The conclusions are: (1) subjects in the educated group had better perception, more detailed knowledge, were more aware, and had better attitudes in regard to regional and global environmental problems than those in the community group; (2) more education is needed to develop environmental actions and ethics in developing countries; (3) non-formal environmental education through popular mass media should be used more widely and frequently, and more detailed information on the environment should be provided to literate people by newspapers and other means.
The literature on the effects of catastrophic wind disturbance (windstorms, gales, cyclones, hurricanes, tornadoes) on forest vegetation is reviewed to examine factors controlling the severity of damage and the dynamics of recovery. Wind damage has been quantified in a variety of ways that lead to differing conclusions regarding severity of disturbance. Measuring damage as structural loss (percent stems damaged) and as compositional loss (percent stems dead) is suggested as a standard for quantifying severity. Catastrophic wind produces a range of gaps from the size caused by individual treefalls to much larger areas. The spatial pattern of damage is influenced by both biotic and abiotic factors. Biotic factors that influence severity of damage include stem size, species, stand conditions (canopy structure, density), and the presence of pathogens. Abiotic factors that influence severity of damage include the intensity of the wind, previous disturbance, topography, and soil characteristics. Recovery from catastrophic wind disturbance follows one of four paths: regrowth, recruitment, release, or repression. The path of recovery for a given site is controlled both by the severity of disturbance and by environmental gradients of resources. Recovery is influenced also by frequency of wind disturbance, which varies across geographical regions. To develop robust theories regarding catastrophic wind disturbance, the relative roles of different abiotic and biotic factors in controlling the patterns of severity of damage must be determined. These patterns of severity and environmental gradients must then be tied to long-term dynamics of recovery.
Changes in mangal area were quantified in the eastern Exmouth Gulf over six years (1999–2004) after Cyclone Vance using Landsat TM satellite imagery and aerial photography. Vance was the strongest tropical cyclone ever to impact the Australian mainland before 2006 and produced wind gusts of more than 280 km h−1. Image data were processed using ENVI™ and IDRISI™ software. Three sets of Landsat TM images from 1999 (a few days before the cyclone), 2002 and 2004 were used, along with 2004 digital aerial photography. A ‘common’ subset of 904 km2 was selected from all images and classification was developed using ISODATA™ unsupervised classification to identify spectrally distinct areas followed by principal component analysis (PCA), vegetation indices and supervised classification. Some 12,800 ha of mangrove habitat was present before the cyclone and approximately 5700 ha (44%) was removed by it. Most mangroves lost (74%) between 1999 and 2004 were converted either to bare sediment or to live saltmarshes and this occurred mostly between 1999 and 2002. Five basic categories of damage were conspicuous from imagery and field observations, and evidence suggests that much of the loss was due to the longer term consequences of sediment deposition or smothering, rather than the immediate effects of wind or waves. Mangroves exhibited accelerated recovery between 2002 and 2004, and around 1580 ha regenerated during this time, amounting to a return of 68% of their former coverage. At this recovery rate we estimate that they should have returned to their pre-cyclone area by 2009. Over half of the saltmarsh habitats (54%) were removed by the cyclone (4060 ha) but their recovery has been far more rapid than mangroves. After 5 years, saltmarshes had returned to 87% of their previous area. The 5700 ha of mangrove habitat damaged by Cyclone Vance exceeds any anthropogenic impact that has ever taken place in Western Australia by several orders of magnitude.
The resilience perspective is increasingly used as an approach for understanding the dynamics of social–ecological systems. This article presents the origin of the resilience perspective and provides an overview of its development to date. With roots in one branch of ecology and the discovery of multiple basins of attraction in ecosystems in the 1960–1970s, it inspired social and environmental scientists to challenge the dominant stable equilibrium view. The resilience approach emphasizes non-linear dynamics, thresholds, uncertainty and surprise, how periods of gradual change interplay with periods of rapid change and how such dynamics interact across temporal and spatial scales. The history was dominated by empirical observations of ecosystem dynamics interpreted in mathematical models, developing into the adaptive management approach for responding to ecosystem change. Serious attempts to integrate the social dimension is currently taking place in resilience work reflected in the large numbers of sciences involved in explorative studies and new discoveries of linked social–ecological systems. Recent advances include understanding of social processes like, social learning and social memory, mental models and knowledge–system integration, visioning and scenario building, leadership, agents and actor groups, social networks, institutional and organizational inertia and change, adaptive capacity, transformability and systems of adaptive governance that allow for management of essential ecosystem services.
Storms are considered to have significant impacts on the development of chenier plains, particularly through the devastation of mangrove vegetation, but also in terms of winnowing sand and shell from mudflats and forming chenier ridges. Shoal Bay, in the Beagle Gulf, northern Australia, contains a small chenier plain, which was struck by a severe tropical cyclone, Cyclone Tracy, on Christmas Day 1974 as it devastated the city of Darwin. The morphology, vegetation and stratigraphy of the plain are described. The plain is underlain by lower intertidal sand with shell hash. A radiocarbon age of 6130 years BP, indicates mangrove colonisation of this flat at the time that sea level stabilised around its present level after the postglacial transgression. Subsequently, progradation of mudflats has occurred, especially around 2300 years ago, and shells of this age are found both in growth position from within the mudflats, and incorporated into the shelly chenier ridges. A further phase of build-out, and subsequent erosion is reflected by stumps and in situ bivalves being excavated presently on the foreshore, radiocarbon dating about 900–1100 years BP. Within this context of evolution, Cyclone Tracy can be seen to have had severe consequences upon the patterning of mangroves, with extensive windthrow of Ceriops, and defoliation of Rhizophora at the western end of the plain. Recovery of the mangrove vegetation has been gradual, and is still incomplete. However, the storm had little influence on the pattern of landform development. Indeed, the aerial photographic sequence indicates a trend by which sand shoals are gradually reworked landwards, in places moving through mangrove vegetation. The study suggests that rather than pronounced regional episodes of alternative mudflat buildout and erosion, both processes occur simultaneously at different points along this foreshore.
February 23-25, 2010, Phuket, Thailand Nine species of seagrass were found around Lampi and neighbouring islands of the Myeik Archipelago, Myanmar. Those species were Cymodocea rotundata, Cymodocea serrulata, Enhalus acoroides, Halodule pinifolia, Halodule uninervis, Halophila beccarii, Halophila decipiens, Halophila ovalis and Thalassia hemprichii. Meadows occurred on the east side of islands on flats inshore of coral reefs where they were sheltered from the monsoons. The largest meadows occurred on the eastern sides of Nyaung Wee, Bo Cho and Lampi Islands, and were mixed intertidal meadows with up to six species, not including E. acoroides or H. decipiens. The former was concentrated around the Ko Phawt Island group and the latter occurred in clear water greater than five metres deep on the west side of Nyaung Wee Island. The size of the most significant meadow at Lampi Island was estimated to be 28 hectares. Estimates were made of percent seagrass cover along transects across that meadow. Sampled sites with seagrass averaged 43% cover, including 27% C. rotundata, 11% T. hemprichii, 5% H. ovalis. Dugong feeding trails were found in dense patches of H. ovalis in March 2008 at Lampi, and at both Nyaung Wee and Lampi Islands in November 2008. Those trails are the first concrete evidence of the occurrence of a resident dugong population in the Myeik Archipelago.
The hypothesis that species richness in tropical, tidal (mangrove) forests in the eastern and western portions of the Australian continent is influenced by different suites of environmental parameters is investigated. Maximum and minimum temperatures were positively correlated with species richness in both regions. Increasing temperatures led to increases in species richness. Tidal amplitude is inversely related to species richness in the east and west. Estuary length, the size of the surrounding catchment, rainfall variation and the frequency of tropical cyclones have significant effects on species richness in eastern but not western mangrove forests. Estuaries which are long and have large catchments tend to have more species than those being shorter with smaller catchments. Although similarities do exist, there are important differences between eastern and western mangrove forests in the response of species richness to the environment.
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