The Issues of Transplanting Mangroves
I have been asked several times on my recommendations for transplanting mangroves but I don't think folks really like to hear the answer. If good methods exist to reforest mangroves and allow them to adapt in their natural habitat with very little human assistance, we want to avoid transplants as much as possible. There are many successful transplant initiatives in the region and any attempts of such should really consider the lessons learnt to avoid situations like this picture. Healthy young mangroves were chosen for this transplant exercise in an area north of Ambergris Caye. The mangroves were still very much alive for many months after the transplantation, as can be noted from the healthy green leaves. However, the mangroves may undergo a period of shock from which they may not recover, especially if the substrate and salinity conditions vary considerably from their initial environment. This would result in poor foliage and root structure and dwarfed trees. Such trees would not be able to provide the intended or desired functions; coastal resiliency, nursery habitat etc. In my opinion the greatest loss of examples such as these is the great effort invested in the approach
Good messaging for keeping mangroves close to home when they are planted, and yes in general it's best to let natural processes dictate what grows where. Unfortunately, on the front side of San Pedro, those natural processes are most off the table. Mangrove can grow there, but removal has been substantial. Interesting that whoever planted these managed to get them to survive at all with tertiary roots and branching already underway. Larger trees normally experience greater shock when they are moved. It's the small seedlings that normally survive.
The original picture above was taken in January 2012 but we are unsure when the mangroves were actually transplanted. We did a site visit last week and find the mangroves still alive but there doesn't seem to be much growth progress in the past 2 years. My assumption is that the transplants were taken from a high nutrient, low-energy environment. The fact that they are still alive in this windward side of Ambergris Caye emphasizes the reliency of the mangroves but the substrate and hydrology difference is too great. Will the mangroves overcome this shock or will they remain stunted?
You can see a patch of mature mangroves on the top left of the picture. Mangroves are patchy in this area as natural recruitment is very slow and unpredictable. When they do take, their growth can be affected by yearly storm surges and other factors. Elbert's description sounds similar to a couple natural recruits we have been observing at the REM sites. Although they are located in nutrient-rich and protected seagrass shoals, they seem to be very slow growing . The foliage blooms nicely once they get a reasonable network of secondary prop roots going. Given that the REM mangroves we put in 4 years ago didn't seem to have the problem, we assume it's because of the occasional storm surges. The REM site is located about 10 minutes south of this site.
I've been watching one at my dock for 11 years and it has only a few more leaves than it did when I first noticed it. It's growing in a turtle grass bed beach side. My best guess is not enough nutrients as it would get in the back lagoon.
Belizean Mangrove Conservation Network