The story of surprising "Keystone Species" of Vultures (and Wolves)

A "keystone species" is an animal that plays an oversized role in an environment. Typically, removing this species has a follow-on result that disrupts a stable ecosystem*. Think of the absence of Mountain Lions in California. The lack of these predators allowed skyrocketing numbers of deer in the state. Or the vast numbers of impalas in Africa, which are the main diet of nearly all large predators on that continent.

And occasionally, we find a surprising species we did not know was essential and only find out after they are gone. Like honeybees. Or, in this case, vultures.

Vultures are carrion eaters; that is, they pick clean the carcasses of dead animals after the primary and secondary predators are through with a dead body. In India, the case for vultures was made in a surprising way. The 10s of millions of birds started dying in the last '90s and early 2000s. In 2004, it was found that the new generics of an anti-inflammatory medicine used on cattle were toxic to vultures. By 2006, the number of vultures had declined by 95%. They were functionally extinct.

The results have been horrible. Without vultures to eat all the dead flesh, it rotted and entered the environment, polluting rivers, and drinking water. The number of wild dogs (feral - if you do Wordle, you know) grew exponentially, dining of dead animals. These dogs in India carry rabies, infecting millions of people. All told, scientists have pegged the extra deaths at 500,000 a year. With no practical way of changing this in the short term.

The introduction of wolves back into the Northern US also had an unexpected result. I've talked about how they positively affected the ecosystems of the Northern Rockies and negatively affected ranchers in Montana and Wyoming. But another effect has been to keep deer populations down. This has actually reduced car / deer accidents by 25% in Wisconsin. The economic benefit is 63 TIMES the negative effect on livestock in the area.

Of course, livestock farms don't profit from those savings which is a problem of who benefits and who is hurt. But that is for a different time. LINK 

*My first major at UCLA was Geography Ecosystems, which I loved. But you had to take Biology, which I hated (and got a D in) and so it was on to Geography & Economics. I don't think they offer a Geography Ecosystem degree now as Geography itself expanded to focus on this.