Indus Delta Research Articles

Explaining the de facto open access of public property commons: Insights from the Indus Delta mangroves

Public property common pool resources in many developing countries are often portrayed as being in a dismal state, allegedly due to their governments’ inability to manage them sustainably. While this explanation may have some merit, it is certainly inadequate. Instead, we argue that public property commons degrade partially because governments, in their attempt to obtain an overall societal balance, sometime accord low priority to some resources and bestow their ownership to an agency that may lack the appropriate mandate. While for many governments, this tendency is deliberate, it results in a de jure public property commonly exhibiting de facto open-access status and creates a situation where anybody may benefit but nobody feels responsible for the conservation and management of such resources. Based on the policy and institutional analyses of mangrove management in the Indus Delta of Pakistan, we propose such a case for theoretical debate on the issue. We conclude that instead of packaging and allocating rights to a single entity, rights in complex CPRs may be defined and allocated separately to different entities to produce socially desired goods and services. No matter how complex it seems, such an arrangement is necessary to deal with the complexity inherent in various socio-ecological systems like mangroves.

Late Pleistocene–Holocene clay mineral record from the Great Rann of Kachchh basin, Western India: Implications for palaeoenvironments and sediment sources

The present study uses clay mineralogy to delineate a ∼17 ka record of palaeoenvironmental/palaeoclimatic changes in the recently uplifted palaeogulf of Arabian Sea i.e. Great Rann of Kachchh (GRK). Situated on continental margin of Indian subcontinent and flanked by Indus delta, the GRK basin has preserved continuous record of post glacial sedimentation. Clay mineral studies on two long cores (∼60 m and 50 m long) show more abundance of physical weathering products (illite and chlorite) over the chemical weathering products (smectite and kaolinite). We show that the GRK sediments depict multiple sources of sediment input. Dominance of illite-chlorite suggests GRK received sediments dominantly from the Himalayan terrain with minor contribution from adjacent regions. We present the oldest clay mineralogical signature of an interval of intensified monsoon conditions during the late Pleistocene (∼17.7–16.3 cal ka B.P.). Monsoon became stronger before ∼8.4 cal ka B.P., and whereas the mid Holocene weakening of monsoon occurred after ∼7 cal ka B.P. Despite the differences in source region and composition of clay mineral records from the GRK with northeastern and southeastern Arabian Sea, the sedimentation responded to major climatic shifts that have occurred since the LGM.

Environmental flow requirements and impacts of climate change-induced river flow changes on ecology of the Indus Delta, Pakistan

Modification of Indus River flows to meet anthropogenic needs has seriously undermined the ecological benefits the river generates in the deltaic region. This paper provides an assessment of ecological conditions of the Indus Delta under different climate change scenarios by using ecological health of the Indus River as a proxy. First, we assessed the existing state of deltaic ecology and categorised it into an arbitrary environmental management class (EMC). Then, using Global Environmental Flow Calculator, we determined the Environmental Flows (E-flows) that are required for the Indus delta in (i) the present, and (ii) in the future under two climate change scenarios. Our analysis shows that due to inadequate and inconsistent release of E-flows downstream of Kotri barrage, deltaic ecosystems have deteriorated overtime. Our analysis reveals that under climate change Scenario 1, more flows may be available that can bring river flows close to natural E-flows. Under Scenario 2, there may be reduced river flows to the extent that E-flows required under prevailing conditions would not be possible. The study concludes that if the current deterioration of aquatic ecology continues, it will be challenging to maintain present, or achieve higher ecological management class (EMC), regardless of the changes in river flows in the future. In this light, there is a need to interlink economic and development needs of communities with environmental needs of Indus River in the deltaic region. Most importantly, there is a need for ensuring climate-compatible e-flows in water regulating sites such as Kotri Barrage.

Vulnerability of the Indus River Delta of the North Arabian Sea, Pakistan

<div> <p>Seawater intrusion has been a serious problem in the Indus River Estuary (IRE) for decades. The literature reviews, hydrological and meteorological observations were analyzed to examine and discuss the causes and consequences of seawater intrusion in the IRE. Both sea water intrusion and coastal erosion are having a devastating environmental and social impact and the whole ecosystem of the Indus Delta is facing serious threat. The Indus deltaic region is not only threatened by continuing activities upstream but also by the neighboring sea in the south, due to the impacts of local weather conditions. Observational results suggest that seawater intrusion reaches 84 km upstream in the IRE during the dry season. Extensive field investigations and a high resolution coastal ocean model are urgently needed for future study.</p> </div> <p> </p>

Reply to the comment on “Geochemistry of buried river sediments from Ghaggar Plains, NW India: Multi-proxy records of variations in provenance, paleoclimate, and paleovegetation patterns in the Late Quaternary” by Singh et al. (2016), Palaeogeography, Palaeoclimatology, Palaeoecology 449 (2016) 85–100

In the comment on our paper (this issue), Clift et al. (2016) compared our recently reported radiogenic Nd-isotopic record in two drill cores (Singh et al., 2016) with those from the Hakra floodplain sediments and Indus Delta sediments. While they agree with the concept of erosion patterns in the western Himalayan sources being climatically modulated, they offer an alternative interpretation for our reported variability in the radiogenic Nd-isotopic values. Here, we show that the Nd-isotopic values for the Holocene succession instead can be explained by the bedrock geology of the source region of these sediments. Moreover, we note that whereas our paper considers a ~75ka fluvial depositional record, their comment is only based on the post-Last Glacial Maximum (LGM) record. When considering the longer record, their arguments do not negate the main conclusions of our original paper.

Mangrove Ecosystem Services: Indus Delta (PQA), Sindh

Mangroves of the Indus Delta are the world’s fifth largest assemblage, and the largest in the arid zone. Mangroves of Indus delta (PQA) provide immense benefits, products and unrecognized regulatory services. Products of Direct Economic Value: Fish, Minerals and food. There are Products of Natural System (intangible) supplies of rich nutrients to support productivity. Coastal communities benefit in a multitude of ways from Mangrove ecosystems. Collectively, these benefits are known as ecosystem services. The ecological role of mangrove ecosystems in the Indus Deltaic area of Port Qasim Authority (PQA) is, economically and socially significant. The Mangroves are well known for their high biological productivity and their consequent importance provided to the coastal community in terms of services and products of direct and indirect value to the adjacent coastal waters. Mangrove Ecosystem services are regularly involved in the provisioning of food and services and the decomposition of organic wastes. They export organic matter, mainly in detritus form of leaf litter to the marine environment, thus providing a highly nutritious food source for themselves and for the Benthic and terrestrial animals found in the mangrove areas, as well as for those in neighboring estuarine and marine ecosystems. Apart from nutrient export, mangroves also contribute to offshore fisheries by acting as nurseries and shelters for many species of commercially important finfish and crustaceans. Degradation of Indus Deltaic mangrove in PQA would destabilize the economic potential and the livelihood of communities’ which include services and benefits offered by the mangrove ecosystem. Rehabilitation and conservation of mangroves ecosystem in PQA is essential for sustained biological productivity in the region.

Marine Ecological Assessment for LNG Terminal at Port Qasim

Multinational companies intend to develop a Liquefied Natural Gas (LNG) terminal with floating storage and regasification arrangement (FSRA) in the jurisdiction of Port Qasim. Approximately 500 MMSCFD or 3.5 million tons per annum of LNG would be transferred through a mooring arrangement, which would require marine works/structures such as a berth for docking and mooring of LNG Carriers and Floating Ship Regasification Arrangement (FSRA) i.e., unloading, storage and vapor recovery and return unit and pipelines to the delivery point for transport to off-takers. The FSRA will deliver the re-gasified liquefied natural gas (RLNG) via jetty and onshore associated facilities to the gas network operated by the in-country transmission pipeline providers SSGCL and SNGPL. The approach channel of Port Qasim is associated with Gharo Phitti Creek System consists of three creeks: Gharo Creek, Kadiro Creek and Phitti Creek has tidal creeks and are with associated mangrove and mudflats ecosystems that are linked with a network of creeks in the Indus Delta. Dredging will be required to create the berthing and the turning basin of diameter 400 to 700 m with a depth of -13.5 m below chart datum (CD). Approximate dredged material would be upto 5.5 Million cubic meters. The dredged material will be utilized for the reclamation and to construct shore protection structure. Land Area of 75-100 acres with water front of 1000 m has been allocated in the PQA for this project. This would be the first time that LNG terminals are being set up in PQA.

Fluvial–Eolian Interactions In Sediment Routing and Sedimentary Signal Buffering: An Example From the Indus Basin and Thar Desert

Abstract Sediment production and its subsequent preservation in the marine stratigraphic record offshore of large rivers are linked by complex sediment-transfer systems. To interpret the stratigraphic record it is critical to understand how environmental signals transfer from sedimentary source regions to depositional sinks, and in particular to understand the role of buffering in obscuring climatic or tectonic signals. In dryland regions, signal buffering can include sediment cycling through linked fluvial and eolian systems. We investigate sediment-routing connectivity between the Indus River and the Thar Desert, where fluvial and eolian systems exchanged sediment over large spatial scales (hundreds of kilometers). Summer monsoon winds recycle sediment from the lower Indus River and delta northeastward, i.e., downwind and upstream, into the desert. Far-field eolian recycling of Indus sediment is important enough to control sediment provenance at the downwind end of the desert substantially, although the proportion of Indus sediment of various ages varies regionally within the desert; dune sands in the northwestern Thar Desert resemble the late Holocene–Recent Indus delta, requiring short transport and reworking times. On smaller spatial scales (1–10 m) along fluvial channels in the northern Thar Desert, there is also stratigraphic evidence of fluvial and eolian sediment reworking from local rivers. In terms of sediment volume, we estimate that the Thar Desert could be a more substantial sedimentary store than all other known buffer regions in the Indus basin combined. Thus, since the mid-Holocene, when the desert expanded as the summer monsoon rainfall decreased, fluvial–eolian recycling has been an important but little recognized process buffering sediment flux to the ocean. Similar fluvial–eolian connectivity likely also affects sediment routing and signal transfer in other dryland regions globally.

Climate change vulnerability and adaptation options for the coastal communities of Pakistan

This study aims to explore climate change induced socio-economic vulnerability of mangrove-dependent communities in the Indus Delta. We evaluate the linkages between vulnerability indicators by relating a community perceptions with observed and projected climate change scenarios. In evaluating these linkages, some key questions are considered such as: what are the likely socio-economic drivers contributing to community's sensitivity? Are these drivers impacting the community and how much is the community's coping potential to climate change? What are the key adaptation options necessary for increasing the community's resilience? This study is carried out in a coastal town (Keti Bandar), which is located in the Indus delta. This region is highly sensitive to declining fresh water flows, changing climate and meager socio-economic resources of local population. We have used the Composite Vulnerability Index (CVI) approach in order to draw a general picture of the community's vulnerability under a changing climate in Keti Bandar. The data for three CVI components (exposure, sensitivity and adaptive capacity) are collected at household level through questionnaire-based survey in six villages, however for exposure, secondary data is also acquired. Our assessment shows that these coastal communities, either engaged with the fishery or agriculture sector, are not only exposed, but are also highly sensitive to climate change driven threats. Moreover, lack of access to basic facilities, inadequate income diversification, and low education levels are negatively affecting the adaptive capacity of the entire local population. However, the communities' nature of dwelling, their strong family networks, and their ability to migrate contribute positively to their adaptive capacity.

Environmental Injustice in Pakistan: Impacts of Upstream Dams on Indus Delta and its Inhabitants

The aim of this study is to focus on the adverse impacts of upstream dams on Indus delta and its inhabitants. The large dams and barrages, besides their global economic significance, have become the focus of strong discussion on account of their frequently severe social and environmental impacts. These negative impacts do not impinge on all people but people who are poor powerless and belong to marginalized ethnic minorities. Since the inception of Pakistan, Punjabi a dominant ethnic group in Pakistan controls armed forces and key political institution and make all decision without considering the interests of Sindh. The construction of dams raises serious environmental justice concerns, with economic benefits for upper riparian Punjab and social and environmental costs for Sindh. The construction activities on Indus River were accomplished largely without getting consensus from Sindh violating the agreement between Sindh and Punjab. Excessive water diversion by Punjab has resulted in the economic, social and ecological problems in Sindh. Deltaic communities of Sindh who draw their livelihood directly from communal access to land, water, forests, coastal mangroves, and other ecosystems are being the hardest hit by the construction of large dams. Sindhi people, especially deltaic people are subjected to environmental injustice due to their subordinate status in Pakistan. DOI: 10.5901/ajis.2015.v4n1s2p11

Sea-level responses to erosion and deposition of sediment in the Indus River basin and the Arabian Sea

Changes in sea level are of wide interest because they shape the sedimentary geologic record, modulate flood-related hazards, and reflect Earth's climate. One driver of sea-level change is the erosion and deposition of sediment, which induces changes in sea level by perturbing Earth's crust, gravity field, and rotation axis. Here we use a gravitationally self-consistent global model to explore how sediment erosion and deposition affected sea level during the most recent glacial–interglacial cycle in the northeastern Arabian Sea and the Indus River basin, where fluvial sediment fluxes are among the highest on Earth. We drive the model with a widely used reconstruction of ice mass variations over the last glacial cycle and a sediment loading history that we constructed from published erosion and deposition rate measurements. Our modeling suggests that sediment fluxes from the Indus River are large enough to produce meter-scale changes in sea level near the Indus delta in as little as a few thousand years. These sea-level perturbations are largest closest to the center of the Indus delta, and they grow larger over time as sediment deposition increases. This implies that the elevation of sea-level markers near the Indus delta will be significantly altered by sediment transfer over millennial timescales, and that such deformation should be accounted for in studies that use paleo-sea-level markers to infer past ice sheet volume or explore local processes such as sediment compaction. Our analysis highlights the role that massive fluvial sediment fluxes play in driving sea-level changes over >1000-yr timescales from the Indus River, and, by implication, from other rivers with large sediment fluxes.

Analysis of Land Surface Temperature and NDVI Using Geo-Spatial Technique: A Case Study of Keti Bunder, Sindh, Pakistan

Keti Bunder is a small coastal community situated at about 200 km south east of Karachi. It has four major creeks namely Chann, Hajamro, Kangri (Turchhan) and Khober with an arid subtropical climate and temperature remaining moderate throughout the year. This paper reports the application of an integration of Remote Sensing (RS) and Geographic Information Systems (GIS) for analysis and monitoring of the relationship of land surface temperature (LST) with Normalized Difference Vegetation Index (NDVI) in the area. LST is one of the critical elements in the natural phenomena of surface energy and water balance at local and global extent. [1-5]. Remote sensing in accord with tradition utilizes the NDVI to provide specific information on vegetation abundance to the LST–vegetation relationship. For mapping purposes, satellite images of Landsat-5 ETM+, Landsat-7 TM and Landsat-8 OLI / TIRS images, acquired on March 08, 2000, April 29, 2010 and April 08, 2014 respectively, were used. The results indicate that the maximum land surface temperature increased gradually from 39°C in 2000, to 42°C in 2010 and 45°C in 2014. Due to global warming and climatic changes. Keti Bunder of the Indus delta has experienced a serious condition over the past few years; the local communities have suffered badly from climate change impacts as heavy rainfalls, floods and cyclones have forced people to migrate to other places for their livelihood and shelter. However, mean NDVI value increased to -0.009 in 2014 as compared to 2010 (-0.165), due to several plantations of mangroves being established by the government. In the past, the mangrove forest was degraded due to lack of freshwater and seawater intrusion. The rate of degradation of mangrove forest in the delta was approximately 6 percent per year between 1980 and 1995 and only a small percentage of mangroves are now considered to be healthy [6-7].

Occurrence and temporal variation in the size-frequency distribution of2 bloom-forming jellyfishes, Catostylus perezi (L. Agassiz, 1862) and Rhizostoma pulmo (Cuvier, 1800), in the Indus Delta along the coast of Sindh, Pakistan

Blooms of jellyfishes were studied at 3 sites, namely Bhanbore, Mirpur Sakro, and Keti Bunder. The sampling was carried out from April 2005 to March 2006. Only 2 species of jellyfish, Catostylus perezi and Rhizostoma pulmo, were found in samples. C. perezi was present at all 3 sampling sites, whereas R. pulmo was found only at Keti Bunder. Specimens of C. perezi appeared in the subsurface waters for a period of 6-8 months during April to August 2006 and February to March 2006. The smallest specimens of C. perezi appeared in January, and a gradual increase in size was observed in the population until August. The smallest specimens of R. pulmo were found in February, and their largest specimens occurred in July. The numeric abundance of medusae in zooplankton was also studied. They were more abundant at Mirpur Sakro, with a peak in December and January, while at Keti Bunder their highest number was noted in May. Their number at Bhanbore was comparatively lower than at the other 2 sites. No significant difference in physical oceanographic factors such as salinity, pH, dissolved oxygen, and suspended load of the sampling site was found, except for water temperature.

A Review of the Status of the Indian Ocean Humpback Dolphin (Sousa plumbea) in Pakistan.

Limited historical and new information on Indian Ocean humpback dolphins, Sousa plumbea, in Pakistan are reviewed. Although present along most of the coast, S. plumbea concentrates in the mangrove-lined creek system of the Indus Delta (Sindh), Miani Hor (Sonmiani Bay), Kalmat Lagoon, Gwadar and the Dasht River estuary (Gwater Bay, Jiwani). Other areas of distribution comprise the Karachi coast, Kund Malir, Ormara and Pasni. In the Indus Delta, 46 small-boat surveys conducted monthly (minus July and October) in 2005-2009, documented 112 sightings (439 individuals) in major creeks, smaller channels and nearshore waters. Group sizes ranged from 1-35 animals (mean=3.92±4.60). Groups of 1-10 animals composed 91% of total (27.9% single animals). An encounter rate of 0.07-0.17 dolphins km(-1) lacked a significant trend across survey years. A discovery curve remained steep after 87 dolphins were photo-identified, suggesting the population is vastly larger. In Sonmiani Bay, Balochistan, during 9 survey days in 2011-2012, group sizes ranged from 1-68 animals (mean=11.9±13.59; n=36), totalling 428 dolphins. Incidental entanglements, primarily in gillnets, pollution (especially around Karachi), overfishing and the ship breaking industry in Gaddani, pose major threats. Incidental catches occur along the entire Pakistani coast. Of 106 stranded cetaceans, 24.5% were S. plumbea. Directed takes in Balochistan, driven by demand for bait in shark fisheries, have reportedly declined following dwindling shark stocks. Habitat degradation threats include depletion of prey and increased maritime traffic. Domestic sewage and solid waste pollution are predominant on the Balochistan coast, especially at Miani Hor, Kund Malir, Ormara, Kalmat Lagoon, Pasni, Gwadar and Jiwani. An exhaustive habitat assessment combined with appropriate fishery management is the only way to safeguard the future of S. plumbea in Pakistan.

Evaluation of Land Cover Changes at the Coast of Sindh through Successive Landsat Imageries

Satellite remote sensing is the most readily available and updated data source for detection, quantification, and mapping of Land-use/Land Cover (LULC) patterns and changes because of its repetitive data acquisition, digital format suitable for computer processing, and accurate geo-referencing procedures. The objective of the study is to analyze the land cover changes and to examine the Land Surface Temperature (LST) with other climatic effects on the Sindh coastal region. Satellite images of Landsat-7 ETM+, Landsat-5 TM and Landsat-8 OLI/TIRS were used in the study, acquired on March 08, 2000, November 20, 2009 and April 08, 2014 respectively. The land cover classes selected for the study are vegetation, mudflat, built-up/vacant land, shallow water and deep water. Maximum likelihood supervised classification and LST techniques were used in the study. The results of the classification mainly consist of land cover classes for 2000, 2009 and 2014, respectively. The land cover in the study area is under the serious threat of climate change. The major cause of ecological, environmental and land use degradation of Indus delta is reduction in fresh water flow, sea water intrusion and natural disasters. Sindh coastline is widely exposed to the disasters like heavy rains, floods, frequent storms and cyclones. This coast faces cyclones approximately every year. Eastern part of Sindh Province is at high risk of tropical cyclones. It is a huge threat to the land covers, biodiversity and human population.

Examining Spatio-Temporal Change Detection in the Indus River Delta with the Help of Satellite Data

The morphology of a river thalweg in a deltaic environment is continuously reshaped by the interactive balancing of the fluvial and marine hydrodynamic processes. Fluvial flow parameters such as volume and flow velocity are favorable to increase the width of thalweg and develop a braided pattern in river course within a delta region. The present study utilized historical satellite images to show that as result of the development of the world largest water divergent networks, the Indus River discharge and sediments load discharge into the Indus delta have been enormously depleted in the last 150 years. Satellite images revealed significant and successive narrowing of the thalweg and distinct widening of the course of the Indus River near the delta. Based on the model results, we show that the style of the rapid morphological changes demonstrates seaward widening and the landward narrowing of the Indus river course and its thalweg. Our results indicate that anthropogenic diversions of the flow in the upstream region of the Indus River have resulted in the devastating domination of marine hydrodynamic processes over the weakened and destabilized natural fluvial processes in the delta region.

Ecological impacts of altered environmental flow on Indus Deltaic ecosystem, Pakistan: a review

The Indus River Delta plays a central role in the lives of the people, economy, environment, and ecological well-being of the region. Indus River originates from Mansarovar Lake in Tibet, India at an elevation of about 5182 m. The River Indus flows for about 2880 km down into the Arabian Sea through the Indus Delta. Indus Delta is situated in Keti Bunder, a coastal town in district Thatta, Sindh, Pakistan 180 km away from Karachi City. There are 17 major creeks making up the Delta. Waters of the River Indus have been dammed or diverted upstream. Only a fraction of water and most of the times no water is released to the Delta region and this resulted in drastic ecological disaster at Indus Delta. The Delta land is reduced and its biodiversity, ecosystem, and its resources are under threat. The objective of this paper is to make an analysis of various documents and works carried out by the environmental organizations on Indus Delta in relation to declined water flows. Reports show that the frequency and intensity of cyclones has increased in the last 30 years. Other environmental changes have only served to increase the vulnerability of the region. Beginning in the mid-19th century a huge irrigation infrastructure was developed upstream drawing water from the Indus River and its tributaries, and since then a series of barrages and dams have been built leading to over-extraction of water for agriculture. Reports show that river flows into the delta have decreased as much as 90% from the 1990s. The result is a reduced flow of nutrient rich silt, and growing sea intrusion destroying mangrove ecosystems and causing land erosion. Community livelihoods have been negatively affected by a decline in agriculture, shortage of drinking water and population displacement. This review attempted to present an overview of the impacts on the Indus Delta resulting from various driving forcing that has brought the Delta to the brink of death and destruction. DOI: http://dx.doi.org/10.4038/jepsl.v3i1.7310 Journal of Environmental Professionals Sri Lanka, Vol. 3 No. 1 2014, 11-21

Assessment of vegetative Phenology with respect to leaf elongation pattern of Avicennia marina and Rhizophora mucronata in Hajambro creek, Indus delta, Pakistan

Leaves emergence and the rate of elongation have been studied in Hajambro creek in Indus deltaic region, Pakistan. Leaves emergence was found higher during the summer months (mostly pre-monsoon period), that was March April, May and June. Leaves of A. marina that were observed from March to July, till the leaves reached their maximum length (about 77 mm), showed a gradual increase in their length, reaching maximum in April. Leaves of Avicennia marina reached their maximum length (about 77 mm) in about 113 days. The leaves showed gradual increase in their length, reaching maximum in April (0.97mm d-1). The per-day increment in length was 0.54 mm d-1. As reaching their maximum length (77mm), the per-day increment in the length gradually slower down. The leaves of Rhizophora mucronata were observed from February to November. The leaves of Rhizophora mucronata showed elongation rate of 0.24 mm d-1 from the day of the first observation till the leaves reached their maximum length (120 mm). The maximum time required by the leaves to reach their maximum length (120 mm) was 236 days. The rates of elongation of leaves are also fast in summer. The rate of elongation of the leaves was found to be highly correlated with the temperature (p

Distribution and dynamics of mangrove forests of South Asia

Mangrove forests in South Asia occur along the tidal sea edge of Bangladesh, India, Pakistan, and Sri Lanka. These forests provide important ecosystem goods and services to the region's dense coastal populations and support important functions of the biosphere. Mangroves are under threat from both natural and anthropogenic stressors; however the current status and dynamics of the region's mangroves are poorly understood. We mapped the current extent of mangrove forests in South Asia and identified mangrove forest cover change (gain and loss) from 2000 to 2012 using Landsat satellite data. We also conducted three case studies in Indus Delta (Pakistan), Goa (India), and Sundarbans (Bangladesh and India) to identify rates, patterns, and causes of change in greater spatial and thematic details compared to regional assessment of mangrove forests.Our findings revealed that the areal extent of mangrove forests in South Asia is approximately 1,187,476 ha representing ∼7% of the global total. Our results showed that from 2000 to 2012, 92,135 ha of mangroves were deforested and 80,461 ha were reforested with a net loss of 11,673 ha. In all three case studies, mangrove areas have remained the same or increased slightly, however, the turnover was greater than the net change. Both, natural and anthropogenic factors are responsible for the change and turnover. The major causes of forest cover change are similar throughout the region; however, specific factors may be dominant in specific areas. Major causes of deforestation in South Asia include (i) conversion to other land use (e.g. conversion to agriculture, shrimp farms, development, and human settlement), (ii) over-harvesting (e.g. grazing, browsing and lopping, and fishing), (iii) pollution, (iv) decline in freshwater availability, (v) floodings, (vi) reduction of silt deposition, (vii) coastal erosion, and (viii) disturbances from tropical cyclones and tsunamis. Our analysis in the region's diverse socio-economic and environmental conditions highlights complex patterns of mangrove distribution and change. Results from this study provide important insight to the conservation and management of the important and threatened South Asian mangrove ecosystem.

Changes in Organic, Inorganic contents, Carbon Nitrogen ratio in decomposingAvicennia marinaand Rhizophora mucronataleaves on tidal mudflats in Hajambro creek, Indus delta, Pakistan

Leaf decomposition of Avicennia marina (Forskål) Vierh in Denkschr and Rhizophora mucronata (Poiret) was studied in situ using litterbags in Hajambro creek, Indus deltA. A single exponential model was presented, which best described the rate of decomposition for both the species. The rate of decomposition was species specific, A. marina leaves decomposed slower than the R. mucronata (p