One summer, I worked in a poop lab.

When I signed up for the conservation gig at the National Zoo in Washington, D.C., I thought I would get to watch cute tamarins and penguins and panda bears play. But I guess I didn't read the job description closely enough.

The only contact I had with the animals was through their scat.

I handled marble-sized marmoset droppings, earthy elephant dung and everything else in between. I scooped it, dried it, burned it and dissolved it in acid that could eat your face off. Why did my employers put me through this?

For one thing, poop can be a powerful indicator of an animal's health, and it's a whole lot easier to follow an elephant around with a shovel than bring it down with tranquilizers to draw a vial of blood.

And beyond learning about a single animal, many samples taken together can predict the vitality of an entire population -- how many animals there are, what they're eating, whether or not they are sick or reproducing. And it doesn't just work at the zoo. In the wild, those small scat samples like the ones that I studied can tell conservationists about the health of an entire ecosystem, from the plants and animals living in it to the prosperity of the people that depend on those natural resources.

Caroline Fraser's new book, Rewilding the World: Dispatches from the Conservation Revolution, provides both those poop-level and people-level views of conservation projects across the globe and helps us see how they're all interconnected.

"The environment is the economy," she writes, making the direct link between two facets of life that people often view quite separately. "No problem -- not poverty, not climate change, not the economic downturn -- can be addressed without simultaneously restoring the systems that are life itself."

Fraser, a veteran author and essayist, travels with scientists, conservationists and community leaders across the globe for her detailed, on-the-ground reporting, letting their stories unfold in candid accounts of what's working and what isn't.

At Botswana's seasonally verdant Okavango Delta, Fraser explores a project designed to protect and maintain the vast inland oasis that attracts hoards of wildlife during the rainy season and serves as an elephant habitat during the dry season. This critical water resource also supports an increasing number of farmers who are trying to grow crops in arid Botswana, giving the community a reason to help preserve it.

From her experiences in southern Africa, Fraser concludes that local support for conservation projects is paramount. Conservation imposed on people from outside forces is bound to fail.

At New York's former Fresh Kills landfill on Staten Island, Fraser discovers another type of conservation project. This time the aim isn't to protect a critical resource, but to restore a degraded habitat by turning 150 million tons of garbage into a 2,200-acre park.

Rewilding is as circuitous as it is ambitious. The book tackles a lot of big issues as Fraser takes a whirlwind tour of the world's major conservation projects. She winds around the theme of grassroots activism and local conservation as the key to connecting and preserving fragmented habitats, but she never quite nails it down. It seems at times that in the face of overwhelming poverty and conflict around the globe, even all-important local support may not be enough to stave off the self-destructive tendencies of humans.

But Fraser remains an idealist. She toys with the idea that conservation has reached a tipping point. Around the world, local communities, scientists and politicians alike are reaching the consensus that wildlife is important for sustainability, especially when it comes to ecosystems that are stressed by the needs of a growing human population.

Though Fraser writes with a sense of urgency and peril, she ends on a note of hope -- that we have what it takes to protect and preserve critical ecosystems before it is too late.

And for me, the book offers a sense of consolation: perhaps my lonely summer in the poop lab wasn't for naught.