What is the core of your research?
Broadly speaking, my work tries to outline the social costs of bio-diversity losses. Ecologists have been telling us that we are losing species left and right but that doesn’t explain how this loss of bio-diversity and ecosystems affects us in terms of its impacts on human well-being.
A large part of my work tries to figure out this multifaceted puzzle by analysing what happens in a region in terms of tangible outcomes when it undergoes a significant decline in species. A complement to this work is to see how effective conservation policies are and whether these tend to have large indirect costs as impacts on land or labour markets.
What are the social costs which you found in your study on substituting biological pest control?
We tend to think of pest control as done with human-made chemicals — but the world has always gained from biological pest control. Out in nature, crop pests have natural enemies which benefit us. Such pest control might not be as effective as chemical insecticides but it’s free and doesn’t pose the health hazards of toxic compounds in insecticides. I found species of bats in the United States feed on insects — ecologists hypothesised that they provide a very important form of biological pest control and if they declined, farmers would have to compensate by increasing their use of chemical insecticides.
Now, in 2006, a wildlife disease called White Nose Syndrome spread, which made bats wake up during their winter hibernation — they had nothing to feed on then and couldn’t survive. Bat populations declined very sharply. I utilised this natural shock to see whether farmers responded by increasing their use of insecticides — they did by about 30%.
That validated the claim that humanity benefits economically from nature’s provision of biological pest control. But the effects go beyond the agricultural landscape because as farmers use more insecticides, the latter mostly get eroded by water and wind and generate off-farm exposure. I found in places affected by White Nose Syndrome, in the years after exposure, human infant mortality rates increased by over 5% on average, driven by internal causes and not accidents, etc.