There are comprehensive initiatives to protect these intertidal habitats, e.g. sea wall. However, the problem lies in that authorities would not like to invest in these initiatives as the effect can not be discerned in short term.

Broadly three main strategies are possible:

1) More effective land use planning to conserve existing areas of mangrove and prevent their conversion to agriculture, shrimp farming or development. Enabling mechanisms could involve protected area designations, local community participation/empowerment and greater recognition of the protective properties of mangroves against storm surges and tsunami;

2) Improved consideration of the long term effects of dams and flow regulation on rivers that can greatly affect the input of sediments to many mangrove coasts. While it is not easy to de-engineer large river catchments it is important to know whether sediment shortage is a factor that could be addressed through improved sediment conservation measures within eroding mangrove zones;

3) Carefully targetted mangrove restoration. Technical capability and experience is improving in this area - see the following links: http://www.mangroverestoration.com/  http://mangroveactionproject.org/  Benefits can include: conservation, fisheries and improved protection against storm surges and tsunami.

Internet searches for the following search terms should be be useful: "mangrove restoration" "Mangrove" AND "shrimp farming"

I wish you success with mangrove conservation.

Dear Subrata Trivedi Ji, Yes i agree with you Mangroves are ut most essential part of coastal ecosystem. As they always protect us from various calamities like Tsunami. But very littile is being done to protect them. Here are few links attached which have some important information on arresting depletion of mangroves. Thanks

http://tribune.com.pk/story/479554/saving-coastal-forests-worried-experts-say-lack-of-freshwater-causing-mangrove-depletion/

http://www.indiaenvironmentportal.org.in/content/367686/fresh-lease-of-life-likely-for-mangroves/

Conversion of mangroves into aquaculture is already substantial and likely to increase manifold over the coming years. Beyond conversion, the effluent of aquaculture may effect mangroves. Most mangroves and marine coastal zones are in effect open access commons with, at best, informal artisanal marine fishery rights. Local and Regional land use planning authorities have usually no offshore jurisdictions. And the national state has usually no local representatives or experts on the spot. Allocation and registration of local ownership and use rights in mangroves would seem necessary. 

Article The living commons of West Tyrol, Austria: Lessons for land ...

Article Eutrophication of mangroves linked to depletion of foliar an...

By adopting innovative sustainable construction practices in infrastructure delivery. These include;

1. Transplanting existing mangroves that are affected by construction projects and processes,

2. Replacing any felled mangrove during construction by planting the same number in another approved location.

This requires effective environmental law and jurisdiction.

Much can be said about the great  importance of mangroves. It is important to add the urgent need of awareness and education about of the paramount importance of mangroves in an increasing sea level scenario induced by climate change. Education and awareness must reach all levesl of society, from local communities to national level governments. Climate change is a great threat for many parts of the world, but also can be taken as an opportunity to warn and convince about the urgency of protecting mangroves  and promoting their sustainable use.

As contributions are rather abstract, both on the institutional and technical level, I will try to become more concrete than my preceding contribution. 

"Community" is not a legal person with authority; instead, a municipality, village council or registered public law association (e.g. of fishermen), could be, depending on the law of the land.

Removal of each tree (including mangrove) for shrimps farms must be compensated by the developer through replanting a tree elsewhere, as is legislated and implemented on the land in various countries. Forestry Departments are often the competent authority. Project investment budgets for shrimp farms and EIAs must include a budget-line for replanting.

The above raises several issues; often the development of shrimp farms in mangroves takes place gradually and spontaneously on tidal land with unclear tenure without competent authority and consequently EIAs appear rare in this context. In other words, good governance is a basic condition for progress here. Further, planting of mangrove is an immature technology to the best of my knowledge. I know only of a partially successful attempt in the Philippines. 

Dear Subrata,

The above mentioned ideas are welcomed. I also list some of the opportunities.

Just a word of caution on replanting mangroves as mitigation for destroying mangroves in an area.. replanting may have a very low success rate due to various reasons (improper planting, lack of follow up care, different environment that may lead to mortality). Also, a long-standing mangrove ecosystem cannot be recreated overnight, as there are layers of peat and soil, along with a highly diverse invertebrate community. Wherever possible, existing mangrove ecosystems must be protected. In addition, other areas can be planted, as mentioned by Mathiventan, Hein, Malcolm and others.. 

I very much agree with Amartya Saha's most timely answer. Very careful consideration of mitigation schemes are required if it is intended that the mitigation forms part of a permission for development of an established mangrove zone. I can list some of the considerations as follows:

1) The area designed for mitigation should generally be larger than that lost due to any development - that is to allow time for the development of ecological quality within the newly mitigated area. In effect the mitigation would be attempting to substitute quantity of new habitat created to offset the quality of any established mangrove lost;

2) The location for mitigation should ideally be a former mangrove zone as there may be remaining substratum that could aid or accelerate the restoration process;

3) The mitigation area ideally should be close to or within a region contiguous with the habitat it is designed to replace. That way there is the possibility for migration to the new area so there is no net feeding or breeding area loss for the mobile species affected;

4) Mangrove habitat banking could be a useful concept to develop. It could involve potential developers funding mangrove restoration or creation in advance of any proposal/permission to develop established mangrove - that way it is more likely to achieve a good balance between any mangrove lost or gained since the quality of the mangrove mitigation would be known.

All of these measures require organisation, funding and technical expertise to maximise the probability that any mitigation would genuinely offset the qualities of any mangrove areas developed. It makes it even more important wherever possible to steer development away from established mangrove zones and focus on restoring damaged areas to increase mangrove areas rather than to concentrate on concepts of no net loss.

I see great potential in selectively adapting and applying habitat conservation principles developed over the past 20 years for saltmarsh and wetland environments from higher latitudes. I see the key transferable principles/methods as follows:

A) Habitat loss/gain accounts (including future predictions or extrapolations) for defined regions to determine the scale of the problems and the requirements for habitat protection and restoration;

B) Compilation of guidance manuals for good practice in mangrove management, restoration and creation. This could include a database of case study examples of management or restoration and a communication forum for solving of common problems and sharing of good practice;

C) Investigation of the potential for habitat banking to improve the mitigation process for those instances where it is impossible to protect established mangroves from development.

Internet searches for "saltmarsh restoration" "managed realignment" "habitat banking" should provide supporting literature and examples of these principles in action. I have two technical reports on my Researchgate account that document some of these principles as follows:

https://www.researchgate.net/publication/269402513_The_Solent_Coastal_Habitat_Management_Plan_Final_Report_Vol_1

https://www.researchgate.net/publication/269402590_The_Solent_Coastal_Habitat_Management_Plan_Final_Report_Vol_2

I invite comment as to how transferable and practical for mangroves these ideas are and I wish you all success in mangrove conservation.

Technical Report The Solent Coastal Habitat Management Plan Final Report Vol 1

Technical Report The Solent Coastal Habitat Management Plan Final Report Vol 2

Amartya, your caution is appreciated and valid; my experience shows that by legislating replanting the trial and error practice as well as fundamental research may be initiated and funded; individual small shrimp farmers may not have the means to do so, but corporate operators often have.

Thanks Malcolm for useful references.

I've just come across some recently published work highly relevant to this question which I thought that I should share as follows:

A new report by the United Nations Environment Programme (UNEP) indicates that mangrove forests have major untapped social and economic potential. Especially underestimated are their values as carbon stores. The report provides guidance on restoration methods and presents case studies of successful projects. 

http://www.espa.ac.uk/news-events/espa-news/2014-12/60247

http://www.unep.org/pdf/Guiding_principles_for_delivering_coastal_wetland_projects.pdf

A second UNEP report “Carbon Pools and Multiple Benefits of Mangroves in Central Africa - Assessment for REDD+” estimates that the carbon benefits from mangroves in Central Africa could be as high as US $66 billion not including benefits from fisheries, coastal protection and other ecosystem services.

http://www.unep.org/pdf/REDDcarbon_lowres.pdf

A third UNEP report comprises an assessment of satellite-based monitoring for mangroves “Monitoring the Restoration of Mangrove Ecosystems from Space” which concludes that satellite remote sensing can detect mangrove restoration efforts and therefore can be included as a useful tool in planning and monitoring mangrove management projects

http://www.unep.org/pdf/REDDcarbon_lowres.pdf

My current awareness source that informed me about these new reports is

http://coinatlantic.ca/index.php/aczisc-coastal-update-e-newsletter

I wish all the followers of this question success in their research.

Thanks for the resources, Malcolm, great perspectives too ! I wonder if one can also use Google Earth for detecting/monitoring mangrove restoration projects. I did a study of mangroves in the Ruvu estuary, Tanzania, and subsequently was quite impressed with the resolution of GE to note specifi patches of mangroves. Of course, GE won';t be able to indicate the health/water stress etc of the mangroves, which are emerging areas of work using remote sensing in mangroves.

Great references, Malcolm. In practice, the situation is complex on at least two accounts. A couple of days ago I waded through mangrove at the Kosi Bay estuary at the Indian Ocean coast of South Africa at the border with Mozambique. Expanding mangrove: positive for carbon sequestration; however, negative for local fisheries; several fish kraals were completely overgrown and others threatened by expanding mangrove. Like always, the question here is who wins and who looses, and are the winners able and willing to compensate the losers? Do the winners even perceive the losers?

And of course expansion or contraction of mangrove, like any forest, can be monitored by using satellite imagery; the valid question is here why such forest monitoring is not standard practice after three decades of satellite remote sensing. Apparent technical and institutional hurdles are discussed in the featured publication under my profile.

Amartya,

I think that Google Earth is superior to the satellite sources on resolution allowing individual tree crowns to be resolved permitting detailed visual interpretation mapping of patterns of fragmentation/consolidation, frontal advance or retreat and agricultural encroachment. Its problem is that some locations have better coverage than others and there may not be appropriate historical imagery with which to make comparisons. If you are lucky with your location then its possible to click through the available historical photography using the historical images function and you can see the changes in front of your eyes - absolutely fantastic for a quick scoping survey! I've just looked at the infamous Benoa land reclamation area in SE Bali (immediately to east of Kuta resort) and found great imagery for 2003, 2009 and 2014.

I would guess that satellite imagery could offer a wider choice of images if it were important to select particular tidal conditions, lighting or a wider variety of imagery wavelengths and it would be more consistent when covering larger areas since Google Earth is very much a mosaic of different image qualities, resolutions and survey dates. I would recommend reading the UNEP report and perhaps comparing the case study satellite images included within it with the corresponding locations viewed using Google Earth - I would guess that Google Earth would win hands down, but only IF is has appropriate coverage.

The correct link for the UNEP 3rd report is:

http://www.unep.org/pdf/Monitoring_the_Restoration_of_Mangroves.pdf

Apologies for the incorrect link in my previous answer. Anyhow I must now tear myself away from Google Earth as I have a lecture to prepare for Monday.

PS Hein, thanks for your comment - I agree with the points that you are making. In all areas of coastal management there are always difficulties in translating apparently sound high level policies into practical ones that can be implemented on the ground. Funders are too often reluctant to invest in enabling mechanisms.

How do we protect mangroves in local communities in developing countries where the exploitation of the mangroves is the main livelihood. I mean areas where the subsistence of the local community depend on the exploitation of the mangroves.  In most cases, the mangroves are used as source of fuel (firewood) or farmland (crop and shrimp faming) for both domestic and local industries. In such scenario the policy of conservation/protection of mangroves from exploitation may not be successful if the local people are not educated about the value of mangrove conservation to the community. In addition the local community should be engaged and supported to develop an alternative livelihood independent on the mangroves. Most of the time researchers do their best to provide the necessary measure and strategies to facilitate policy development on mangrove conservation and restoration. However, the major setback in this case is the lack of financial and technical support to the local people to develop the required alternative livelihood to facilitate mangrove conservation and protection. The question is how do we bridge this gap? Who is responsible to provide the needed support?

 Many important points were given by  so many learned scintists, beyond all, Strict rules should be implemented by the Govt. agencies  for protection of these fragile ecosystem

Issac, there have been instances of USAID funding to develop community-based coastal management programs ( eg http://www.crc.uri.edu/) , with an interdisciplinary focus on income generation, that seeks alternatives while attempting sustainable harvesting of mangrove poles, crabs, seafood, etc. However, such efforts are few, and much of the funds going in for international development is wasted in overheads. Mobilizing more of these funds for coastal community programs involving all stakeholders can be a way. For that however, the donors would need to be made aware of the critical condition of most of the tropical shorelines,  for which there needs to be some common forum for scientists and donor program managers to interact..

Selection of a suitable growing medium is mandatory for all kind of mangroves. In this regard, the following paper will provide a broad idea on selecting appropriate substrate for vegetations:

Preprint Analysis of Physical and Chemical Properties of Alternative ...