Nearly all major environmental groups saw their donations increase, some significantly so, with President Trump in the White House, according to an Axios analysis of tax filings.

The big picture: This is classic Washington. When one side is in power, interest groups on the other side often see more financial support — which is why environmental groups are on the rise during one of the most aggressive regulatory rollbacks in American history.

Driving the news: Between 2015 and 2017, donations to 10 of America’s most influential environmental groups increased between 20% and 149%.

That’s the last full year before Trump’s election and the first full year since his victory. (2017 is the most recent year with widely available forms.)

This chart, adjusted for inflation, shows 10 of the total 18 we analyzed. All but two saw growth.

Expand chart Data: Forms 990; Get the data; Chart: Harry Stevens/Axios

By the numbers:

Oceana's 149% increase was by far the biggest. Its CEO, Andy Sharpless, says its fundraising jumped partly because of its campaign to stop the Trump administration’s plans to expand offshore oil drilling, and also because of big donations by Bloomberg Philanthropies and the Wyss Foundation to expand ocean conservation efforts around the world.

Its CEO, Andy Sharpless, says its fundraising jumped partly because of its campaign to stop the Trump administration’s plans to expand offshore oil drilling, and also because of big donations by Bloomberg Philanthropies and the Wyss Foundation to expand ocean conservation efforts around the world. Earthjustice and League of Conservation Voters saw their fundraising nearly double between 2015 and 2016, suggesting a sharp spike in donations after Trump’s November 2016 election.

The median increase was 30%.

Two groups out of the 18 we analyzed — Conservation Fund and Environmental Working Group — raised slightly less money in the year after Trump's election than the year before it.

What they’re saying: Axios reached out for comment to all of the groups included on the chart. Most said Trump’s election was behind the increase, while a couple said the two were unrelated.

“Americans see the damage the Trump administration is doing to our environment and know that we are nearing a point of no return on climate,” said Sam Sankar, senior vice president of programs at Earthjustice.

In its fundraising, the group has touted its “Overruling Trump tracker,” which tracks all lawsuits the group has filed against Trump: 122 when we started writing this a few weeks ago, and 127 last we checked.

Yes, but: It’s hard to confirm a direct line of causation between the increased donations and Trump’s election. Several factors could be going into this, including an improving economy.

Nonetheless, the data shows a notable increase after Trump’s election when comparing it to earlier years going back to 2013.

The intrigue: In addition to big donations from deep-pocketed institutional donors like Bloomberg Philanthropies, individuals are also changing how they give, according to interviews and conversations we've had. Here's one.

Bob Finnegan, a 65-year-old attorney in Connecticut, has decided to donate one bigger pile of money to one environmental group — Earthjustice — instead of smaller donations to several groups.

“I decided I really like what Earthjustice was doing the most because they are really going after these people,” Finnegan said in a recent phone interview.

Finnegan says he typically gives $1,000-$1,500 a year, and although that number hasn’t increased recently, his single donation to Earthjustice has. He also says he plans to up his donations in the coming years.

What motivates him the most, he says, is his anger over the Trump administration’s removal of federal protections of public lands in the West.

What we’re watching: If this trend accelerates or flat-lines if Trump wins reelection in 2020. If a Democrat wins, we’ll be watching to see if donations drop off as the threat to environmental policies lessens.