Mangrove Nursery Lessons


Meaningful Volunteer and CERV Philippines runs a mangrove nursery in the Barangay of Cabolutan – just off the main road between Long Beach and San Agustin on the way to the Cabolutan Elementary School. Currently there are about
5,000 Rhizophora seddlings (propagules) waiting to be planted. But as we don’t know where to plant them yet, they need constant maintenance and monitoring in the nursery. This document provides volunteers some general information on the nursery, the tasks that have to be done, the problems we are facing and the lessons learned from previous failures.

What has to be done in the nursery?

  • Water the seedlings!
    Especially during dry season and periods with alack of rain the plants should get water at least twice, better three times a week.
  • Clean up and keep weed away!
    Weed is a constant problem that can only be solved by picking it out of the mangrove cups regularly. They extract the nutrients from the soil and grow faster and even bigger than the actual mangrove seedlings.
  • Look for diseases!
    Some mangroves are affected by diseases you can easily spot on the propagules. Separate these seedlings from the rest, clean them and monitor them regularly.
  • Separate seedlings turning black!
    Propagules that lost all their leaves and start to turn black also need to be separated from the healthy seedlings. Small ants colonize them and live in the inside of these dying mangroves. However, when the propagules are still green, there is a little chance for them to recover.

The obvious reason for a mangrove nursery is to get the seedlings being planted when they are big enough. There is no reason to keep them in the nursery for too long. They will even stop growing at a certain point due to bad conditions (lack of sunlight, small cups). But mangroves cannot be planted anywhere on the shoreline – this is especially true for Rhizophora. More things have to be done outside the nursery:

  • Find appropriate planting sites!
    This is a difficult task and needs a lot of time, monitoring and measurement. Find out about the specific needs for this Rhizophora species and look for places on the shoreline with the best conditions for the seedlings (soil, low tide and
    high tide etc.) before planting them.
  • Talk to people!
    Some locals are very interested and even enthusiastic about mangrove reforestation projects. They might also suggest planting sites. Tell them about the problems to face and have a look at the planting site before offering seedlings for planting.

What are the problems we face?

  • Mangrove seedlings stop growing
    The small cups prevent the seedlings from growing further. Propagules in bigger cups grow faster and higher at the same time. More and more seedlings even die! They lose all their leaves and start to turn black. They might develop new leaves, but ants obviously claim these struggling mangrove seedlings as their habitat.
  • Where to plant the mangroves?
    Still it is hard to find out the best places to plant the seedlings with the appropriate conditions for Rhizophara. The Carmen Marine Sanctuary is an example for a badly chosen planting site. Most seedlings already died, the still existing ones struggle to survive.
  • Concentration on planting
    Although planting mangrove seedlings is obviously a major step in every mangrove reforestation project, it is not the only one. Mangrove seedlings are requested for planting from time to time, but without knowing the planting site, constant monitoring and protection of the planting site as well as the communities’ active involvement it is just a question of time until when these seedlings will be washed away by the sea or die like most of them before.
  • Lack of community involvement
    This is actually the most important point to keep in mind: Involve locals! Whatever you do, you do it for the coastal communities in San Agustin. There is no reason for not involving them in every stage of mangrove reforestation. Especially students are excited to learn more about mangroves and will be happy to support you. Measuring, monitoring,planting, cleaning up – get people involved andexplain why it has to be done! This will also raise
    awareness for the mangrove ecosystem.

What lessons can be learned?

Based on our experience from the work in and outside the mangrove nursery there are many lessons that have been learned already. There will be more to come as volunteers will experience new problems and learn about various other important aspects.

Here are some points to keep in mind:

  • The bigger the cup, the better will the mangroves grow!
  • The nursery needs constant maintenance (think of weeds, diseases, mangroves turning black)!
  • The seedlings need a lot of sunlight to grow and should be watered regularly!
  • Rhizophora needs certain conditions to grow up. Seedlings cannot be planted anywhere!
  • Planting of seedlings without further monitoring is waste of time and resources!
  • The community needs to be involved in every single step of the project!


11 Oct 2009