What should we prioritize to try to save from the flood tide of extinction?

“The world is on fire, and we have to do something about it,” said Kate Jones, an ecologist with University of College in London.

Jones was one of the speakers at two Harvard panels last month about the species extinction perils of our Anthropocene age: climate change, overfishing and overhunting, pollution, loss of habitat, invasive species, sea level rise, ocean acidification and all the ugly rest.

Extinction threats are not like a field of bullets hitting everything equally, noted Jones, speaking at a session on Human Imprints on the Tree of Life. Primates are at greater risk than most mammals. Amphibians, palms and corals are particularly vulnerable. Ditto species on islands. Animals with large body sizes, long lives and small ranges are vanishing. Along with, of course, so many other forms of life.

Facing this global storm of extinction with severely limited resources, what should conservation groups and governments prioritize?

One framework for decisions is to safeguard plants and animals with particular values to humans, as food, fuel, eye candy or just insurance for the future, the scientists said. Another framework is to consider the tree of life—protecting genetic diversity so that we can better understand biology and maybe exploit that understanding down the road. (Saving, for instance, the ginkgo tree, full of idiosyncrasies after branching off from other trees 100 million years ago.)

Habitat protection initiatives don’t always follow these outlines, naturally enough. As one audience member noted, many projects in Britain aim to preserve butterflies that remain happily common elsewhere in Europe.

“Most conservation is local, which is fine,” said Ana Rodrigues of the French National Center for Scientific Research. But very few resources work at a global level, Rodrigues emphasized.

One of the few is the Evolutionarily Distinct & Globally Endangered (EDGE) program led by the Zoological Society of London. “We can take attention away from charismatic megafauna like pandas, which are cute and fluffy with big eyes,” remarked Jones. Instead, attention can be paid to offbeat creatures like the pink fairy armadillo. (“It’s another poster child but I think it’s spreading out the love.”)

“We’re in deep trouble,” said Yale botanist Michael Donoghue. “We have to act quickly. The problem is, there are too many things we value.”

Many forms of ecological damage have spread surprisingly quickly across vast areas of ocean, noted biologists at an Ocean Evolution Today seminar. Jellyfish are on the march  as we vacuum up commercial finfish. Two-thirds of the Great Barrier Reef’s coral died off in two years. “In the Arctic, ice algae is disappearing and the entire food web is compromised,” commented Samantha Joye of the University of Georgia.

All too often this marine damage is invisible to most of us, said Boston University’s Randi Dawn Rotjan. Even survival stories can be worrisome–for instance, the killifish that have evolved to shrug off PCB-laced harbors.

More generally, “I’m worried that my children will jump into the water and not know what they haven’t seen,” Rotjan said.

“The most important ecosystems on the planet are almost unknown,” pointed out Bruce Robison of the Monterey Bay Aquarium Research Institute. One case in point: the ocean animals that migrate in “uncountable numbers” up toward the surface at night and then back down during the day, which brings carbon out of the surface waters.

Or we can think of the seafloor hot water vents discovered 40 years ago, which stream out key nutrients and may act “like the ocean’s multi-vitamins,” said Harvard’s Peter Girguis. Life throughout the sea, he added, “is linked to things that happen in the deepest darkest parts of the ocean.”

The scientists applauded the spread of marine sanctuaries, which can provide significant safeguards if established (and enforced) on sufficient scale. So far, sanctuaries have grown most notably in sparsely populated stretches of the Pacific. (The Republic of Kiribati’s Phoenix Islands Protected Area is a coral archipelago the size of California with exactly 24 people, living on one island, Rotjan said.) The High Seas Alliance aims to extend this strategy with protected areas in the no-man’s-lands of the open ocean.

Another positive sign is the rapid growth of sustainable aquaculture, to supplement and replace capture fisheries.

And we also can see payoffs of local and regional marine renewal efforts, such as the massive cleanup of Boston Harbor. Last month, out with a boatful of biologists for a conference hosted by Northeastern University, we were cheered to see harbor porpoises calmly working the clean waters of the Mystic River, in what not long ago was the dirtiest harbor in the U.S.

Top, the “life-size” version of Noah’s Ark built by Johan Huibers of the Netherlands. Bottom, clockwise from panda: Ice algae, pink fairy armadillo, ginkgo berries, mussel.