Abstract: Reductions in natural capital can result in complicated knock-on effects that can connect seemingly unrelated outcomes. This paper focuses on the specific setting where pesticides, a form of non-point source pollution, are used to compensate for falling levels of naturally provided pest-control. I use a natural experiment and find the first causally interpretable results for the adverse health effects of pesticides. Identification exploits mortality shocks to bats – a major predator of insects – that result from the unexpected emergence of a wildlife disease known as White Nose Syndrome (WNS). WNS first emerged in the U.S. in 2006 and started to gradually spread across counties. I use a Difference-In-Differences strategy and find that farmers increase their use of insecticides by 39.6% relative to their mean use. Because insects carry fungi between plants, the use of fungicides increases as well by 20.1% relative to the mean. Using linked birth and death certificates I focus on infant mortality due to non-violent causes for births that were conceived during the pesticides application season of April through July. The infant mortality rate increases by 1.01 deaths per 1,000 births in the counties exposed to WNS. This is driven mostly by female infant mortality and represents an increase of 14.5% relative to the mean. These results suggest that mixtures of pesticide compounds can affect health even if each compound is used below its regulatory threshold.
Traders in illegal wildlife markets have incomplete information regarding the scarcity of different species. If poachers and collectors are targeting rare species, then information shocks on species’ rarity could adversely affect conservation efforts. In this paper I use monthly level data on extinction risk updates, for the period of 2002-2010, and match it with wildlife import data into the U.S. Using a non-parametric event study strategy I demonstrate that information shocks on the extinction risk of species lead to an increase in trade levels by 2.47 to 3.11 standard deviations, relative to the baseline period prior to the update. These results provide evidence that publicly revealing updates about the extinction risks of species can result in better coordination between supply and demand in wildlife trade markets. Therefore, monitoring and enforcement efforts could improve their effectiveness by increasing their focus on species that receive such information shocks.
Work in Progress:
Rats are considered as a global pest and common wisdom among insurance and fire experts attributes about 20-25% of unexplained fires to the gnawing of electric cables by rats. I use zip code level data on fire records, and rat inspections in New York City to provide empirical estimates of the infrastructure damages caused by rats.