Every spring, U.S. colleges and universities shut down for a week or two, allowing students to relax at home or take a vacation from their studies.  Some head to the beaches in Florida or other warm spots.  But more students are trading their vacation opportunities for volunteer work projects in Miami and other cities.

A Dartmouth College student hammers a roof during a spring break service project in Miami

A group of Dartmouth College students is spending break in a low-income neighborhood in Miami building houses with the charity Habitat for Humanity. Leo Anzagira is an engineering student from Ghana. He says the work gave him valuable experience on a construction site.

"It just moves so fast, and the way all the pieces come together, it is faster than what I have seen back home," he says.

Construction work may be unfamiliar to some volunteers, such as math major Evans Amoah. He says few of his colleagues are working so hard during their vacation.

About 14,000 students are building homes with the organization Habitat for Humanity during their spring break vacations

"We did have a chance to visit the beach once, but I could have gone home," he says. "It is hard work, but it is fun working alongside your mates."

Some volunteers will add the experience to their work resumés, and others simply want to give back to the community. About 14,000 students are building homes with Habitat during spring break.  Scores more are helping other projects.

At Everglades National Park outside Miami, Louie Toth is leading a group of students from the University of Wisconsin into remote areas of the forest.

Louie Toth teaches student volunteers to identify and remove invasive plant species in the Florida Everglades

"This is a Brazilian pepper tree, and if you scan the area around it, you will see there is no other vegetation growing around it," he explains.

The Brazilian pepper and other foreign plants were introduced by accident to the Everglades and now crowd out native species. Student volunteers are ripping out these invaders and trying to collect the seeds to prevent new plants from growing.

Wildlife ecology student Samantha Mueller says she understands the problem, because she researched one invasive fish species in Wisconsin.

"It is this crazy creature that takes over the food web, and the species here have never seen anything like it," she notes. "And it is the same with this plant. Look at how many pods. They are everywhere."

The back-breaking work can takes its toll, in the form of injuries, sun burns or mosquito bites.  But many relish the chance to be outside in the sun, especially for students who leave behind cold winter temperatures.

University of Wisconsin students Sarah Zipperle and Samantha Mueller search for invasive Brazilian pepper plants, which crowd out native species

"I have always wanted to see the Everglades, and I thought a hands-on way would be the best way to do that," says Emily Barker, a first-year biology student. "And it is spring break, [so] I wanted to go somewhere warm."

Despite the hard work, students say they get a sense of satisfaction from offering a hand during their break. Sophomore Sarah Zipperle says she enjoyed her Everglades trip more than if she had taken a regular vacation.

"You are also doing something meaningful and worth your time, and it makes you feel you have done something great with your break instead of sitting on the beach at a resort."

It may take years for native plants and trees in the Everglades to return, after the invasive species are removed.  The students hope the mark they leave behind will have a lasting impact.