You can create NFTs which programmatically collect royalties on each sale [0]. This royalty could be used for continued conservation efforts. I don't know much about programming smart contracts but I think one could be programmed such that if it isn't transferred within a certain period of time it could be burned the next time the user tries to transfer it.
You "just" need to tie each NFT to a specific gorilla and raise enough to find someone willing to sell an annuity tied to the expected lifespan of said gorilla.
Or just raise enough for the average investment returns from the one-off sales to fund the charity.
But the person who the money/etherium is sent to could be the charity, no? As in, people donate their digital art or whatever to a charity and the charity auctions off the NFTs to raise money.
That’s the way real life charity fundraisers sometimes work: you donate a physical object and they sell it to raise money. The benefit over you selling at and donating the money is that you don’t have to deal with selling it. The usage of NFTs here would be to take advantage of the mass hysteria(?) surrounding them to drum up the price.
An NFT could work like that, though. There's nothing stopping someone from writing an NFT smart contract that directs a percentage (of any size, including 100%) of future sales to the initial cause.
The NFT standard itself is quite basic, nearly every NFT people talk about are controlled by smart contracts that expand on the standard.
[0] https://rarible.com/create/erc721