Restoration techniques urgently need to be upscaled
[20150811 Day 12 Set 1]
SECORE: Dirk, the SECORE team is currently testing different methods to upscale coral reef restoration based on sexual reproduction. Why is such a large-scale approach needed?
Dirk Petersen: Coral reef restoration is still in its infancy. Current methods regardless whether using asexual or sexual recruits are too cost and labor intensive. The scale of what actual restoration activities can achieve so far is relatively small―although a lot of effort is put into it. But if you look at the results of these conservation activities, they cannot face the geographical scale of reef decline. Current restoration projects are rather useful for outreach and raising public awareness since local communities may be involved. This is very important for holistic coral conservation, but to directly aid reef rehabilitation, restoration techniques urgently need to be upscaled. Also, it is important to point out that any restoration efforts will only make sense, if the area is well managed for example in a MPA, but for some reason, there is a lack of natural recruitment. Having partners on-site, like marine park authorities and environmental agencies, is important for a long-term success.
Can you give us an estimate, how many corals are needed for bigger restoration projects?
Let’s assume that the goal is to establish at least one coral recruit per square meter in a degraded reef. For one hectare, which is an area of 100 by 100 meter, you would need 10,000 coral recruits, assuming an unlikely success rate of 100 per cent. More realistic is a success rate of 50 to 25 per cent, which requires 20,000 to 40,000 coral recruits per hectare! This is approximately the magnitude that current restoration efforts may reach. Projects this size may help to restore a reef site damaged by a ship grounding. But to address reef decline on a regional scale of a magnitude of square kilometers, we talk about at least 2-4 million corals per square kilometer!
But these numbers of corals cannot be produced manually?
I don’t think so, especially if you look at asexual propagation techniques like fragmentation. You have to handle every single coral fragment manually during the production process for several times. First, you take each fragment and attach it to a substrate. Then you need to transfer all these corals to a nursery and in a third step you outplant them on the reef. Just imagine, you have to do this by hand for a million corals! There have been projects done on a scale of a few ten thousands corals which is a great start, but it took people a lot of effort. With the existing techniques it seems unrealistic that restoration in its current state can become a significant management tool to help fighting global coral reef decline.
How does SECORE address this challenge?
Our main question is: How can we upscale our restoration techniques in a way that we reach numbers of corals that are needed to rehabilitate coral reefs on a larger scale. There are different ways! Using sexual recruits for upscaling reef restoration has one big advantage compared to other techniques. If you look at the production of corals only, it does not matter if you are dealing with 1,000 larvae or one million. Once you know the conditions the particular species requires for settlement, you just create these conditions. Then you can manage thousands of substrates and millions of larvae. The larvae will settle by themselves, no manual help is needed. Therefore, the manpower and time needed to deal with a few hundred larvae or a million does not differ. It is then more a question of providing space and adequate logistics to deal with such quantities. This is where SECORE is right now – upscaling logistics.
[20150811 Day 12 Set 3]
[20150811 Day 12 Set 4]
How much does coral reef restoration cost?
There is a huge range of costs between the different approaches. We just had an elkhorn coral research project finalized in Curacao, where we significantly reduced the cost-intensive nursery period down to two weeks compared to common time periods of one year and more. With this technique, we still had costs of 5 US dollars per successfully established coral. We carried out this study in a relative healthy environment with good water quality. The future will show if reduced nursery times also work under less favorable conditions. Usually nursery periods, are much longer creating costs of more than 50 US dollars per established colony. That means, if you look at a restoration site with the size of a hectare, you quickly need half a million US Dollars to rehabilitate such a small area.
So, using sexual recruits can save you a lot of money?
That is what our work is all about: If you want to do coral reef restoration it has to be in a realistic manner. It has to be payable, because most tropical coral reefs are located in third world countries with little financial opportunities. It is all about reducing costs and establishing the logistics in order to deal with large quantities of corals needed.
What is the main focus of your ongoing SECORE workshop in Mexico?
During the past few years, we broadened our knowledge on restoring endangered species such as the elkhorn coral. We also did a lot of research to upscale restoration efforts. Now, the first pilot project has started in Mexico. In this project we are looking at automating processes, reducing labor and simplifying the tools and material needed. We need to go low-tech, managers and restoration practitioners should be able to get most material right on site. If you look at the areas where coral restoration is mostly needed, you won’t find any laboratory or aquarium installations dotted along the coast. Instead, you work in remote areas. Our major goal is to upscale reef restoration and using low-tech methods and materials that you can get on site.
[20150811 Day 12 Set 2]
How is the pilot study going so far?
Mexico is the ideal location to do such a project. Anastazia Banaszak has managed to get a great network of people together. Basically all important local and national stakeholders are involved. Together, we are looking at the logistics that are needed to deal with large quantities of coral recruits. We are receiving a lot of support, especially from UNAM, CONANP and last but not least the Xcaret Eco Park Aquarium team. They have tremendous logistics and capacities to help us, which is one reason for the big success of this workshop. It will take a few years to get the logistics in place, but we are confident that together with our local partners, we will be able to contribute to upscaling reef restoration activities here in Mexico and at other places in the future.