Threatened site is home to globally important cave system

Many were filled, collapsed and/or buried by the creation of the golf course, and with them went their ecology, species and their potential for eco-tourism.

The Bermuda Environmental and Sustainability Taskforce (BEST) asked renowned cave expert Dr. Tom Iliffe for his assessment of the value of and threats to the island’s caves.

Biodiversity hotspots are defined as relatively small areas with exceptional concentrations of endemic species.

Bermuda’s marine caves readily qualify as hotspots of global significance due to their remarkably rich and diverse community of cave-limited animals.

Seventy-five species, most of them endemic, have been identified from Bermuda caves, including two new orders of crustaceans, one new family and 15 new genera.

Per unit of land area, Bermuda has more caves and cave animals than any country in the world. 

But even on a small island such as Bermuda, caves are not evenly distributed — most of the 150 known caves are located in the narrow strip of land separating Harrington Sound from Castle Harbour, where the island’s oldest limestone, the Walsingham Formation, is exposed.

An estimated 90 per cent of Bermuda caves occur in 10 per cent of the island’s land area. Many of Bermuda’s cave-dwelling animals are even more restricted, having been found only in a single cave or cave system.

Due to their limited distribution, the fragile nature of the marine cave habitat and severe water pollution and/or development threats, 25 of these species are listed as critically endangered.

Amazingly, close relatives of Bermuda’s cave species inhabit similar marine caves in the Caribbean, Eastern Atlantic, Mediterranean and even the Galapagos Islands in the Pacific, suggesting that cave species have been living on Bermuda for tens of millions of years. Due to the absence of light, photosynthetic production of organic nutrients and oxygen does not occur, thus food and dissolved oxygen in cave waters are limited. 

As a consequence, populations of animals are very small and usually found only in deeper, fully marine waters of the caves.

Sinkholes

The Tucker’s Point property is by far the largest single plot of land in Bermuda with Walsingham limestone and as such has an extremely high density of caves and other related karstic landforms, including sinkholes and eroded rock pinnacles. In such areas, rainfall rapidly disappears into the ground and moves down to the subterranean water table, which locally corresponds to sea level in the porous limestone. 

Because of the vertical transport of water, pollutants such as road runoff, fertilizers, pesticides, weed killers and other chemicals are likely to enter the ground water and the caves, with harmful effects on the fauna.

A large percentage of the land surface at Tucker’s Point was modified in the 1930s to create a golf course and undoubtedly untold numbers of caves were filled in or destroyed.

The caves that survived are primarily situated on the steep flanks of hillsides or near their crests where it was not practical to construct fairways. Paynter’s Hill and Quarry Hill have some of the highest elevation cave entrances in Bermuda, and yet many of the caves extend down to sea level and below, honeycombing the hills with a maze of passageways and collapse chambers. 

Because of the vertical nature of the caves, requiring advanced rope work and transport of scuba gear, most are not explored. 

Due to the small entrance sizes of many caves in this area, coupled with dense brush and rampant poison ivy impeding explorers, many unknown caves likely await discovery.

Considering the global importance of Bermuda caves and the critically endangered species that inhabit them, it is essential for a thorough and complete evaluation of caves on the whole of the Tucker’s Point property to be conducted as soon as possible by recognized and qualified experts. 

Destruction

This should include complete exploration and mapping of both the dry and submerged portions of the caves, as well as a faunal inventory of them.

Even with all due care and diligence by the developers, destruction of caves and potential extinction of cave-limited species is a very real threat.

The steep hillsides with little to no soil cover means extensive excavation must occur in order to provide level ground for building sites, as well as for roads and other essential infrastructure. 

During this process, previously unknown caves are likely to be uncovered and even destroyed. 

To lose Bermuda’s most precious natural resources would diminish the attraction to tourists.

To do so for the sake of an already unviable and arguably unsalvageable business venture make no sense at all, ecologically or economically.