Mexico's ecological diversity is among the broadest of any country in the world, with an abundance of ecosystems ranging from the northern deserts to the central conifer forests and the southern tropical rainforests. Mexico also supports 111 million people and welcomes more than 20 million visitors each year. Tourism is one of the country's biggest and most lucrative industries, and while tourism has brought jobs and growth to much of Mexico, it has also created and even accelerated many of Mexico's ecological problems. Cancún might be the highest-profile example: Rapidly developed from a rural outpost to an international resort destination, Cancún imported turf from Florida for its golf courses, inadvertently introducing a disease that wiped out the local coconut palms. The region's mangroves, a key habitat for native species and vital to protecting the land from hurricanes and erosion, have also suffered.

However, tourism has also encouraged development of ecological conservation. Mexico is home to seven of the world's eight species of sea turtle, and the entire turtle population was decimated on both coasts as a result of tourism growth and local overfishing. A recent success story comes from the Riviera Maya, where marine biologists are working with hotels to guard nesting turtles and their eggs.

Mexico's people are proud of their land and culture, and through your travels, especially in rural areas, you will likely encounter ejidos, and cooperativos, or local cooperatives, that offer small-scale tourism services -- this may be as simple as taking visitors on a boat ride through a lake or as visible as controlling access to archeological ruins. Ejidos will also run tours to popular ecotourism destinations similar to those offered by large travel agencies. When you deal with ejidos, everyone you encounter will be from the community and you know that your money goes directly back to them. States with a strong network of cooperatives include Chiapas, Quintana Roo, and Yucatán. Playa del Carmen's Alltournative (www.alltournative.com) is one example of a private company that has created tour options that include local input and grow by sustainable development.

The Mexican Caribbean supports the Great Mesoamerican Barrier Reef, the second-largest reef in the world, which extends down to Honduras. This reef and other marine ecosystems face increasing pressure from sedimentation, pollution, overfishing, and exploitative recreational activities, all newly associated with growing regional tourism. The Coral Reef Alliance (CORAL; www.coral.org) is an example of an organization that, by teaming up with the World Wildlife Fund (WWF; www.wwf.org) and United Nations Environmental Program (UNEP; www.unep.org), has been working to address threats to the Mesoamerican Barrier Reef and improve environmental sustainability throughout the region. CORAL partners with Mexican Amigos de Sian Ka'an, Conservation International, and the Cozumel Reefs National Park in an effort to build sustainability into mass tourism (such as cruise ships and hotels). CORAL assists marine tourism operators in implementing a voluntary code of conduct for best environmental practices. CORAL is soon to spread its influence to the Yum Balam region of the Yucatán Peninsula, where guidelines for whale shark interactions are greatly needed.

One of the best contributions a diver can make to support a healthy reef is to avoid physical contact with the reef during a dive. Talk to your scuba outfitter about proper buoyancy control and body position to avoid damaging these fragile ecosystems.

Tabasco suffered devastating flooding in 2007 that brought widespread suffering to the population, which is among Mexico's poorest. The floods also affected Chiapas, though to a lesser extent. 2010 brought more severe flooding. Tabasco's sinking land, and the extraction of oil and gas, land erosion, and deforestation all contributed to the state's vulnerability.

Ecotourism and sustainable tourism opportunities abound in Chiapas, where a growing number of small, local tourism cooperatives have organized to take tourists on guided hikes, treks, and even kayak expeditions into the state's isolated jungles and nature reserves. The Chiapas Tourism Secretariat has information in Spanish about ecotourism at locations across the state (www.turismochiapas.gob.mx). Two private companies that run ecotours throughout Chiapas are Ecochiapas (Primero de Marzo 30, San Cristóbal de las Casas; tel. 01800/397-5072 toll-free in Mexico or 967/674-7498 in San Cristóbal; www.ecochiapas.com) and Latitud 16 (Calle Real de Guadalupe 23, San Cristóbal de las Casas; tel. 967/678-3909; www.latitud16.com).

The Mesoamerican Ecotourism Alliance (tel. 800/682-0584 in the U.S.; www.travelwithmea.org) offers award-winning ecotours recognized by National Geographic to the Yucatán and Chiapas.

Biodegradable Sunscreen -- Recent scientific studies have shown that chemicals in commercial sunscreen can do long-term damage to coral reefs, collect in freshwater, and even build up in your own body system. The Riviera Maya receives more than 2.5 million visitors every year, many of them drawn to its rare marine environment -- a unique combination of freshwater cenotes and the world's second-largest coral reef. A few ounces of sunscreen multiplied by 2.5 million is equal to a substantial amount of harmful chemicals suspended in the ocean and freshwater. That's why tours to the Sian Ka'an Biosphere Reserve and water parks Xcaret and Xel-Ha ask that you use only biodegradable sunscreen or wear none at all when swimming in their ocean or cenotes.

The label of a biodegradable sunscreen should state that it is 100% biodegradable (and only 100% will do). You can buy it at the parks, but you'll get a better price at local markets. If you're curious, you can obtain a list of banned chemicals by contacting the parks directly. Buy a supply of biodegradable formula before you go from www.mexitan.com or www.caribbean-sol.com.

Animal-Rights Issues

The Yucatán presents many opportunities to swim with dolphins. The capture of wild dolphins was outlawed in Mexico in 2002. The only dolphins added to the country's dolphin swim programs since then were born in captivity. This law may have eased concerns about the death and implications of capturing wild dolphins, but the controversy is not over. Local organizations have been known to staple notes to Dolphin Discovery ads in magazines distributed in Cancún hotels. Marine biologists who run the dolphin swim programs say the mammals are thriving and that the programs provide a forum for research, conservation, education, and rescue operations. Animal-rights advocates maintain that keeping these intelligent mammals in captivity is nothing more than exploitation. Their argument is that these private dolphin programs don't qualify as "public display" under the Marine Mammal Protection Act because the entry fees bar most of the public from participating.

Visit the website of the Whale and Dolphin Conservation Society at www.wdcs.org or the American Cetacean Society, www.acsonline.org, for further discussion on the topic.

Bullfighting is considered an important part of Latin culture, but you should know, before you attend a correo, that the bulls (at least four) will ultimately be killed in a gory spectacle. This is not the case in some countries, such as France and Portugal, but the Mexicans follow the Spanish model. That said, a bullfight is a portal into understanding Mexico's Spanish colonial past, although nowadays bullfights are more of a tourist attraction, especially in tourist-laden Cancún. To read more about the implications of attending a bullfight, visit the website of People for the Ethical Treatment of Animals (PETA) at www.peta.org.

Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.