Facebook’s big News Feed changes — which will show you more posts from friends and family and fewer from public pages — won’t just decrease the reach of brands and publishers, they’re going to hit nonprofits, too.

There are more than 1.5 million nonprofits on Facebook, and many of them have built presences there at the platform’s encouragement. Now, they’re headed into a period of uncertainty inspired by News Feed changes which could diminish a critical tool they use to reach people interested in supporting their causes.

Nonprofits reach many new supporters through Facebook: When they post, nearly half the people who see their updates come from outside the immediate network of people liking their page, according to research from M+R. And some have used the 2.07-billion-user platform to fundraise massive amounts of money. The Syrian American Medical Society, for instance, raised $1.5 million for medical care in Syria last year. A drop in reach on Facebook could set back nonprofits’ efforts significantly.

“For any nonprofit organization, your Facebook page is pretty huge. We have our largest social following on Facebook,” Hannah Orenstein, digital manager at the Malala Fund, told BuzzFeed News. “A decline in reach would certainly not be good for achieving our mission.”

The Malala Fund is a nonprofit that Facebook touts as a “success story” in its nonprofit recruitment efforts, which include a microsite encouraging groups to “Join the 1.5M nonprofits using Facebook Pages to build their communities.” Yet it hasn’t yet received guidance from Facebook on how to…