Dr Cristina Banks-Leite
Dr Cristina Banks-Leite, Department of Life Sciences at Imperial College London, is revealing how much rainforest we need to protect in order to maintain biodiversity in these fragile ecosystems.
I have always loved nature. I grew up with nature all around me on our farm in Brazil’s Atlantic rainforest, and as a young girl, my grandfather would come back from the Amazon with these amazing stories of the things he had seen. I was fascinated, so I think I was always going to be an ecologist.
How much rainforest do we need to protect in order to maintain biodiversity? For the past few decades, the Brazilian government has obliged farmers in the Atlantic forest to set aside at least 20 per cent of their land for rainforest, but there wasn’t any scientific evidence to support whether that was enough. A group of around 50 of us collected data for ten years before I analysed the set as a whole. There was a very clear pattern to show that the birds, mammals and amphibians needed at least 30 per cent forest cover to survive and thrive. Below this threshold you get a huge difference to the type of species available and the habitat becomes unrecognisable.
As a scientist you never know whether the work you have done is going to be taken up by policymakers, but I think our evidence was so unambiguous it provided a clear message. I was proud that, in 2017, the Brazilian government announced it was looking to increase forest cover to a minimum of 30 per cent in priority areas. Currently, many areas fall well below this target, and so our research has also helped identify where reforestation efforts should be targeted. There is a long way to go but even though compliance is not always great, Brazil’s environmental laws are good – 80 per cent of the Amazon rainforest is protected, which puts the conservation policies of other countries into perspective.
Farming is important to the economy but there is a compromise to be had with conservation. Part of our research calculated that compensating farmers, such as Payments for Ecosystem Services (PES), would cost relatively little. I would like to advance that work in future and bring attention to the benefits of paying farmers to protect forest they have or restore it on their land.
While I don’t doubt competition between species is important, I have a feeling that so much attention has been focussed on it in the past because male researchers see value in competition. In reality, there’s a lot more facilitation and positive interactions in nature, and these are only just starting to be explored. There are a lot of women scientists working on mutualistic interactions, which makes me think that what we study often reflects our view of the world. Without women scientists we are missing a whole set of perspectives.