Sonneratia apetala Mangrove Invades the Coast of Brazil

By Alfredo Quarto,

Program & Policy Director

Co-founder, MAP

 

There is a rather urgent situation concerning the bio-invasion of the Sonneratia apetala mangrove species now threatening the coastal wetlands of Brazil. Here is a bit of background information. 

The invasive species Sonneratia apetala is native to SE and S. Asia, and was introduced into China over 30 years ago as a way to buffer China's SE coastal regions from erosion and storms. The S. apetala seedlings were originally brought in from Bangladesh in the late 1980s through the 1990s, raised in nurseries, then planted along extensive stretches of coastline. The reasoning behind the decision to introduce this non-native species to China was that the S. apetala mangrove grew taller and more rapidly than native species, but unfortunately this also meant this introduced species outcompeted the native mangroves, leading to a bio-invasion that today threatens the native mangrove wetlands of SE China. It was also found that its soft stems broke easily from intense winds, and thus S. apetala was not as effective as native mangrove species for storm protection. Today, S. aperala comprises nearly 11% of China's mangroves occupying an area of around 3,000 ha. The rapid spread of S. apetalsa has alarmed the Forest Department, which issued a ban on further such introductions, and initiated an ambitious eradication program to counter this now unwelcome invader. 

Unfortunately, the S. apetala has had too long a grace period to establish itself in China, and so now, after millions of dollars have already been spent on eradication, it may be impossible to halt its advance. Each S. apetala tree produces thousands of seeds, thus colonizing faster than the eradication program can counter.

This situation in China is quite relevant to a new bio-invasion of S. apetala in Brazil because the same problem of uncontrolled spread of S. apetala is today occurring in Brazil. It is believed there the seedlings of S. apetala were brought to Brazil's coast by accident via the ballast waters of visiting vessels from China. The invasive trees were found recently by accident 2km from the Port of Santos, Cubatao-Baixada Santista, State of Sao Paulo, Thus, without intention the uncontrollable spread of S. apetala has recently begun in Brazil, thus needing immediate remedial action to eradicate this invasive species before it's too late to do so.

The Brazilian environmentalist Geraldo Eyslink who directs HC2 Solucoes had stumbled upon evidence of this bio-invasion while carrying out some mangrove restoration work in NE Brazil. Here is his comment concerning this problem:

"A few months ago, we identified the presence of Sonneratia apetala (a species of mangrove from the Indian region but which most likely came through the ballast water of ships from China. We are very concerned and we urgently need to eradicate them. There are 159 trees ( that we managed to register), and with a lot of fruits (around 2,000 fruits per tree (average of three trees that we have already cut down) and each fruit has an average of 70 seeds, which totals 140,000 seeds per tree...."

From the above description, it becomes clear that immediate action is needed to ensure this invasive species does not have the chance to spread throughout the region, as this could have serious consequences for the native flora and fauna. If you would like more information on this issue, please contact Alfredo Quarto at alfredo@mangroveactionprojet.org, or Geraldo Eyslink at geraldo@hc2solucoes.com.br.