Striking paper by Anant Sudarshan and Eyal Frank (via Dylan Matthews at Vox Future Perfect) on the importance of vultures as a keystone species.
To quote the paper and newsletter — the basic story is that vultures are extraordinarily efficient scavengers, eating nearly all of a carcass less than an hour after finding it, and farmers in India historically relied on them to quickly remove livestock carcasses, so they functioned as a natural sanitation system in helping to control diseases that could otherwise be spread through the carcasses they consume. In 1994, farmers began using diclofenac to treat their livestock, due to the expiry of a patent long held by Novartis leading to the entry of cheap generic brands made by Indian companies. Diclofenac is a common painkiller, harmless to humans, but vultures develop kidney failure and die within weeks of digesting carrion with even small residues of it. Unfortunately this only came to light via research published a decade later in 2004, by which time the number of Indian vultures in the wild had tragically plummeted from tens of millions to just a few thousands today, the fastest for a bird species in recorded history and the largest in magnitude since the extinction of the passenger pigeon.
When the vultures died out, far more dead animals lay around rotting, transmitting pathogens to other scavengers like dogs and rats and entering the water supply. Dogs and rats are less efficient than vultures at fully eliminating flesh from carcasses, leading to a higher incidence of human contact with infected remains, and they’re also more likely to transmit diseases like anthrax and rabies to people. Sudarshan and Frank estimate that this led to ~100,000(!) additional deaths each year from 2000-05 due to a +4.2%(!) increase in all-cause mortality among the 430 million people living in districts that once had a lot of vultures, which is staggering; this is e.g. more than the death toll in 2001 from HIV/AIDS (92,000), malaria (53,000), and alcohol use disorders (14,000).
(Cause X, anyone? Preventing a hundred thousand deaths a year for less than half a billion dollars annually clears the GiveWell top charity-level threshold, and half a billion is in the ballpark of Open Philanthropy’s entire annual grantmaking...)
So what to do? For vultures in particular, Sudarshan and Frank say their results “inform current vulture recovery efforts in India, and conservation efforts elsewhere” e.g. parts of Africa and Spain, albeit without elaborating. More broadly, they hope their paper informs better policymaking by providing “a particularly stark example of the type of hard-to-reverse and unpredictable costs that must be accounted for when evaluating the introduction of new chemicals into fragile and diverse ecosystems”, stating “it is plausible that a counterfactual policy regime in India that tested chemicals for their toxicity to at least keystone species might have avoided the collapse of vultures”. They conclude:
In the absence of empirical estimates of the social benefits conferred by different species, conservation policy may be heavily influenced by existence values unrelated to utility. The vulture is not a particularly attractive bird and evokes rather different emotions at first sight than do more charismatic poster-animals of wildlife conservation such as tigers and panda bears. Nevertheless our results suggest that subjective existence values alone may not be the best way to formulate conservation policy.
The remark that vultures are not particularly attractive reminds me of the overlooked plight of farmed chickens, shrimp, insects etc for not being charismatic fauna. (I am admittedly sort of emotionally conflating the welfare of vultures with their ecosystem importance as a keystone species here.)
Striking paper by Anant Sudarshan and Eyal Frank (via Dylan Matthews at Vox Future Perfect) on the importance of vultures as a keystone species.
To quote the paper and newsletter — the basic story is that vultures are extraordinarily efficient scavengers, eating nearly all of a carcass less than an hour after finding it, and farmers in India historically relied on them to quickly remove livestock carcasses, so they functioned as a natural sanitation system in helping to control diseases that could otherwise be spread through the carcasses they consume. In 1994, farmers began using diclofenac to treat their livestock, due to the expiry of a patent long held by Novartis leading to the entry of cheap generic brands made by Indian companies. Diclofenac is a common painkiller, harmless to humans, but vultures develop kidney failure and die within weeks of digesting carrion with even small residues of it. Unfortunately this only came to light via research published a decade later in 2004, by which time the number of Indian vultures in the wild had tragically plummeted from tens of millions to just a few thousands today, the fastest for a bird species in recorded history and the largest in magnitude since the extinction of the passenger pigeon.
When the vultures died out, far more dead animals lay around rotting, transmitting pathogens to other scavengers like dogs and rats and entering the water supply. Dogs and rats are less efficient than vultures at fully eliminating flesh from carcasses, leading to a higher incidence of human contact with infected remains, and they’re also more likely to transmit diseases like anthrax and rabies to people. Sudarshan and Frank estimate that this led to ~100,000(!) additional deaths each year from 2000-05 due to a +4.2%(!) increase in all-cause mortality among the 430 million people living in districts that once had a lot of vultures, which is staggering; this is e.g. more than the death toll in 2001 from HIV/AIDS (92,000), malaria (53,000), and alcohol use disorders (14,000).
(Cause X, anyone? Preventing a hundred thousand deaths a year for less than half a billion dollars annually clears the GiveWell top charity-level threshold, and half a billion is in the ballpark of Open Philanthropy’s entire annual grantmaking...)
So what to do? For vultures in particular, Sudarshan and Frank say their results “inform current vulture recovery efforts in India, and conservation efforts elsewhere” e.g. parts of Africa and Spain, albeit without elaborating. More broadly, they hope their paper informs better policymaking by providing “a particularly stark example of the type of hard-to-reverse and unpredictable costs that must be accounted for when evaluating the introduction of new chemicals into fragile and diverse ecosystems”, stating “it is plausible that a counterfactual policy regime in India that tested chemicals for their toxicity to at least keystone species might have avoided the collapse of vultures”. They conclude:
The remark that vultures are not particularly attractive reminds me of the overlooked plight of farmed chickens, shrimp, insects etc for not being charismatic fauna. (I am admittedly sort of emotionally conflating the welfare of vultures with their ecosystem importance as a keystone species here.)