A matter of balance

 

With New Zealand’s mangroves generally regarded either as a nuisance to be uprooted or a natural vegetation to be left alone, a former NIWA principal scientist says the answer to the controversial ‘what to do with mangroves’ question essentially comes down to how people would like their estuaries to be.

Estuarine, coastal and marine specialist, and director of Streamlined Environmental Ltd, Dr Malcolm Green says choosing between either ‘stopping or suffering the spread of mangroves’ does not actually come down to science. 

“To me that's a values argument… however science can help answer questions around whether removal will be effective in certain areas and what the ecological impacts might be,” he says. “Each setting is unique, and will respond to intervention in a different way.”

Reviews conducted in recent years by a number of scientists show NZ mangroves do have a purpose Green says, with the plants providing a home for some varieties of fish, birds and crustaceans. 

However (Andre and Robin) La Bonte’s work is essentially still correct as, while they are still indigenous trees and serve a function, it is to a lesser extent than tropical forests which are more species rich, and yes we need more work to be done on our mangroves.”

With the plants’ tendency to spread easily and rapidly, Green says there is a necessity to protect other habitats, especially valuable open water areas which become lost once mangroves take root. 

“I wouldn’t say getting rid of them entirely is a good thing to do but I think there’s a good argument for managing our mangrove forests,” he says. “It’s all a matter of balance.”