Officials at Hawaii Volcanoes National Park on the Big Island saw a potential problem a few decades ago with people taking a few rocks home with them as souvenirs. To prevent this problem from escalating, the park rangers created a legend that the fiery volcano goddess, Pele, did not like people taking anything (rocks, chunks of lava) from her home, and bad luck would befall anyone disobeying her wishes. There used to be a display case in the park's visitor center filled with letters from people who had taken rocks from the volcano, relating stories of all the bad luck that followed. Most of the letters begged Pele's forgiveness and instructed the rangers to please return the rock to the exact location that was its original home.
Unfortunately, Hawaii's other ecosystem problems can't be handled as easily.
Marine Life -- Hawaii's beautiful and abundant marine life has attracted so many visitors that they threaten to overwhelm it. A great example of this is Oahu's Hanauma Bay. Crowds flock to this marine preserve, which features calm, protected swimming and snorkeling areas loaded with tropical reef fish. Its popularity has forced government officials to limit admissions and charge an entrance fee. Commercial tour operators have also been restricted.
Hawaii's reefs have faced increasing impact over the years as well. Runoff of soil and chemicals from construction, agriculture, and erosion can blanket and choke a reef, which needs sunlight to survive. Human contact with the reef can also upset the ecosystem. Coral, the basis of the reef system, is very fragile; snorkelers and divers grabbing onto it can break off pieces that took decades to form. Feeding the fish can also upset the balance of the ecosystem (not to mention upsetting the digestive systems of the fish). In areas where they're fed, the normally shy reef fish become more aggressive, surrounding divers and demanding food.
Flora -- The rainforests are among Hawaii's most fragile environments. Any intrusion -- from hikers carrying seeds on their shoes to the rooting of wild boars -- can upset the delicate balance of these complete ecosystems. In recent years, development has moved closer and closer to the rainforests.
Fauna -- The biggest impact on the fauna in Hawaii is the decimation of native birds by feral animals, which have destroyed the bird's habitats, and by mongooses that have eaten the birds' eggs and young. Government officials are vigilant about snakes because of the potential damage they can do to the remaining bird life.
A recent pest introduced to Hawaii is the coqui frog. That loud noise you hear after dark is the cry of the male coqui frog looking for a mate. A native of Puerto Rico, where the frogs are kept in check by snakes, the coqui frog came to Hawaii in some plant material and found no natural enemies.
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.