Ecotourism Case Study: The Bahamas Iguanas
Tourism companies through the Bahamas are increasingly marketing the feeding of endangered rock iguanas as part of their activity packages. But are the benefits to the local community and potentially to conservation worth the health costs being felt by the animals themselves?
Ecotourism helps conservation in many ways. It generates money, jobs and educational opportunities for the local community and it raises awareness of the plight of biodiversity, thus increasing the incentive to protect species and habitats. Overall, it proves that animals are worth more alive than dead.
An increasingly common tourist activity is the feeding of wildlife. It is encouraged for a wide variety of species, yet there is not a whole lot of understanding about the long-term impacts. Potentially, it is beneficial - increasing an animal’s food intake would clearly help it during times of food scarcity, and would improve its body condition, help it develop fat stores and enhance reproduction. The human interaction with the species may even make the human feel more positively towards its conservation.
The health and population impacts on species that are fed by tourists is an area of conservation that is severely under-studied. Yet there is one species for which thorough research has been conducted - the Northern Bahamian rock iguana.
Before the arrival of humans, this iguana ruled in its home range, being amongst the biggest animals on the islands. Today, it is one of the world’s most endangered lizards. Habitat loss due to logging and clearing for development and invasive species such as dogs, cats and pigs brought to the islands by yachtsmen have pushed the iguanas into smaller and smaller areas. It is also the only Caribbean species of iguana to still be hunted for human consumption, and is threatened by poaching for the illegal pet trade.
There are 3 subspecies of Northern Bahamian rock iguana. Two exist on small, uninhabited cays on the 200 km-long Exuma Island chain, and the third is found on Andros Island, which is inhabited by people. The iguanas living on the Exuma Islands occur naturally on eight cays and have become increasingly popular as feeding attractions. Historically, the number of visits was low, at around 20 people per day in the 1980s. But the economic success of tour operators has prompted others to bring more and more tourists, so the number has sky-rocketed to up to 150 people per day, ferried on fast powerboats from Nassau.
Not all iguanas are visited by tourists, some areas are free from visits, and this means that a nice comparison can be made between the iguanas from tourist-visited areas and non-tourist areas. And it seems that feeding these animals is negatively affecting both their health and their behaviour.
The iguanas are naturally vegetarians, their diet comprising predominantly of seven year apple, buttonwood, sandfly bush and wild dilly, however they are opportunistic foragers that graze over 40 plant species. The food the tour operators bring is usually grapes, bread and meat - for the iguanas, not a healthy diet.
Scientists making the comparison have discovered that the sugary grapes resulted in the iguanas from feeding areas having high concentrations of glucose in their blood. Their new diet also caused them to have diarrhoea. Iguana scat usually resembles a cigar, consisting of tightly rolled leaves and fruit that often remain intact, but these iguanas had scat that was looser and more liquid, consisting of grapes and sand. Why sand? Because iguanas were (unnaturally) feeding from the beaches where tourists land. Iguanas usually feed in vegetated inland areas, but when fed by tourists they ingested sand alongside the food. This appeared in the blood test results as they had altered trace mineral levels. Large amounts of sand may even have the converse effect, of making the scat hard and cement-like, leading to constipation, cloacal prolapse and possibly death.
The disproportionate amount of time foraging on the beach meant that they also ingested higher levels of invertebrates or fish that had washed ashore. The greater amount of protein in their diet, also caused by being fed meat such as ground beef by tourists, resulted in the iguanas having higher uric acid levels, making them susceptible to renal disease and gout. In addition, males had raised cholesterol concentrations due to having meat in their diet - males are more aggressive when feeding than females, so eat more of it. And talking of aggression, males also had higher levels of testosterone.
Both males and females had a 100% endoparasitic infection rate. The long-term health and population stability of these animals is clearly in question. Yet it is not just their health that is altered compared to the iguanas from non-tourist areas, their behaviour has changed too.
Scientists have noticed that the iguanas are much less wary of humans. This lack of threat response has worrying consequences in a species so vulnerable to poaching…simply because it makes them much easier to poach. It is easy to pick them off, because they congregate in much higher concentrations on the beach, and they are at greater risk of predation by dogs and cats that come ashore with their human companions. Additionally, the increasingly aggressive behaviour of male iguanas in particular makes them more of a perceived threat to the tourists, so large individuals may be removed by tour operators. Over time, this will reduce the overall body size of the population.
And what about the impact on the ecosystem itself? The iguanas are the largest native herbivores on islands where they occur, so play a vital ecological role by dispersing seeds, modifying the vegetation and regulating plant communities. Changes to their feeding patterns will clearly have implications for the entire habitat and the other species within it.
Understanding these changes in detail, and their long-term implications, is vitally important to the future management of these already endangered animals. Due to the economic and educational advantages that tourism brings to The Bahamas, scientists who have studied this species do not recommend that feeding stops altogether or tourist visits are reduced. Instead, tour operators should use pelleted iguana food, specially formulated to mitigate the provisioning of unhealthy food and provide a more nutritionally balanced diet. Educational campaigns may also help, as may discouraging the references to feeding iguanas in tour company advertisements.
There are examples of successful ecotourism initiatives that are much less harmful to animals. In fact, a similar situation facing iguanas in the Turks and Caicos was reversed through the transformation of tourist activities from direct feeding into a non-feeding walking tour along a boardwalk where tourists could still see iguanas. This has seen no reduction in tourist interest.
The issue of tourism and feeding wildlife is complex, especially when many countries are so dependent on tourism revenue. But short-term economic benefits should never trump the long-term ecological consequences, especially when so little is known. So when you are next on holiday, no matter how acclimated animals seem to be towards humans, never approach or touch them. Let’s keep wild animals wild, and appreciate them from a distance.
With many thanks to Charles R. Knapp from the John G. Shedd Aquarium for his assistance.