CDF STUDIES REVEAL UNWELCOME VISITORS TRAVELLING WITH TOURIST BOATS
Sixteen Galapagos based tourist boats recently participated in a Charles Darwin Foundation (CDF) led study to find out how ship lights might contribute to the dispersal of insects in the archipelago. The study by Lazaro Roque and other CDF entomologists found solutions that will reduce the spread of introduced species to and between the Galapagos Islands.
Although a trip to Galapagos allows visitors the privilege of experiencing nature at its most remarkable, tourism is not without costs to the environment. The boats and planes that arrive daily bring with them insects and other invertebrates that threaten Galapagos ecosystems. Once here, alien species are frequently dispersed between islands by human activity or under their own power.
Results of the study revealed that the large number of external and internal lights used by the boats attracts nocturnal insects, especially moths, and that these species follow the ships to other islands. A total of 171 species were collected during the study. A quarter of these species are introduced to Galapagos and over half of are considered a threat to the biodiversity of pristine islands, such as Fernandina.
"The chances of transporting insects on boats are even higher in the rainy season, which is associated with greater insect activity" commented Roque, whose team found that during a 3 hour period in the dry season, an average of 150 insects were attracted to a boat with 18 external lights. Contrast that with the same amount of time in the rainy season when over three times the number of insects was collected (466).
Simple solutions suggested for the local fleet are the use of light bulbs with colors that are less attractive to insects and turning off lights four hours before a ship's departure, both effective methods to avoid insects alighting on the boats. Said Roque "We have identified cost efficient options that the Galapagos tourist sector can employ to reduce the unnatural spread of species." CDF has also recommended that tour itineraries be reviewed so that pristine islands are not visited
immediately after sites with higher numbers of invasive species.
The transportation of insects from other parts of the world to Galapagos via tourist boats is even more worrying. The routes taken by these boats form a dangerous link between Galapagos and other countries. This creates new pathways for invasive species which are not found on mainland Ecuador and thus currently not at risk of being introduced by commercial airlines or cargo boats that already visit Galapagos on a regular basis.
In 2006 CDF entomologists carried out a survey for the Galapagos National Park to evaluate the risks associated with international cruise liners visiting the islands. During a four hour collecting session aboard the cruise liner M/V Discovery researchers found 43 individuals of six moth species that had been attracted to the ship's lights and traveled on board the ship to Galapagos. Four of the moths are not found in Galapagos and all potentially pose a serious threat to
Galapagos species. Caution suggests that international cruise ships be considered likely vectors of invasive species.
It makes good business sense for the tourism sector to lead the way in preventing the spread of introduced species. Tourism is one of the most important sources of revenue for Ecuador and for Galapagos. The financial and ecological cost of invasive species spreading throughout the islands' fragile ecosystems is far higher than taking early preventative steps to reduce the movement of insects to and around the islands. Working together to find solutions will help ensure that this astonishing and extraordinary community of animals, plants, and people will remain the best preserved oceanic archipelago on the planet.
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