Bermuda

Invasive species and biosecurity

A total of 901 non-native species (marine and terrestrial) was recorded for Bermuda by the RSPB Stocktake (Churchyard et al 2014).

Taxon Total species Non-native species
Invetebrates 5,708 467
Vertebrates 1,281 32
Plants 2,348 402
Casuarina stand (invasive); Brazil Pepper Tree with ripe fruit

Casuarina stand (invasive); Brazil Pepper Tree with ripe fruit

Problems with invasive non-native species

In Bermuda invasive species cause extensive ecological problems. For example, invasive Casuarina trees (Casuarina equisetifolia) over-shade native plants and increase soil erosion, while various species of introduced birds predate the endemic wildlife such as the Bermuda Skink, and displace native birds from nesting sites. The pressures of habitat loss and extensive development have made these problems more acute, as very little natural habitat remains. Bermuda is particularly vulnerable to the introduction of invasive species through the importation of food and other consumer products. These shipments can inadvertently introduce invasive species into the environment. Additionally, people smuggling plants, animals, seeds or fruit back from their vacations could accidentally introduce an invasive species that will seriously damage Bermuda’s environment.

An estimated 95% of the surviving population of native Bermuda cedar (Juniperus bermudiana) was destroyed between 1946 and 1951 following the accidental introduction of two coccoid scale insects. Only an estimated 1% of the original cedar forest survived the blight. Subsequent reforestation using a scale-resistant strain has returned the cedar to roughly 10% of its former abundance, though these efforts have been hampered by the introduction of fast-growing casuarinas and other exotics into much of the cedar habitat

Case Study - The Brazil Pepper Tree

The Brazil Pepper Tree (Schinus terebinthifolius), which is locally often referred to as Mexican Pepper, is arguably Bermuda’s worst invasive species. It was introduced as a garden plant prior to the 1950’s and has since successfully invaded all parts of the island and every terrestrial habitat. Brazil Pepper has been so successful that it has displaced many native plants and drastically altered the habitats it has invaded.

Case study – the Pacific lionfish

Lionfish are native to the Indo-Pacific but in the 1980s some were released off the coast of Florida. Since then, they have spread across the Caribbean and the US East Coast, with the first one recorded in Bermuda in 2000. They are now ubiquitous in Bermuda waters. Lionfish are voracious predators and have a devastating impact on native fish. The lionfish has no natural predators in the Atlantic, and some shallow sites in the Bahamas have 390 lionfish per hectare and the impact of lionfish at these densities has been devastating.

Between 2012 and 2017 the number of sightings of the Pacific lionfish in Bermuda increased from less than 200 to over 1400

Priority invasive non-native species and actions

The main priority invasive species and actions for plant and animal (vertebrate and invertebrate) species are shown below.

Plants

Scientific name Common name More info Actions Other notes
Schinus terebinthifolius Brazil Pepper
Eugenia uniflora Surinam Cherry Gov. Bermuda factsheet (external link) Still sold in garden centres. fruits are edible Looks like native Eugenia.
Casuarina equisetifolia Casuarina
Ficus retusa Indian Laurel
Asparagus densiflorus Asparagus Fern
Livistonia chinesis Chinese Fan Palm
Leucaena leucocephala Wild Mimosa (Jumbie Bean)
Eichhornia crassipes Water Hyacinth
Scaevola sericea Beach Naupaka Gov. Bermuda factsheet (external link) Looks like native Scaevola plumieri
Arundo donax Cow Cane
Sphagneticola trilobata Seaside Creeping Daisy Formerly Wedelia trilobata
Cenchrus setaceus Fountain Grass Formerly Pennisetum setaceum


Animals


Scientific name Common name More info Actions Other notes
Pterois volitans Lionfish A lionfish control programme and related research is being coordinated by the Bermuda Aquarium
Sturnus vulgaris European Starling Gov. Bermuda factsheet (external link) No control action This species is on the IUCN list of 100 of the world’s worst invasive alien species
Pitangus sulphuratus Great Kiskadee Gov. Bermuda factsheet (external link) No control action Introduced from Trinidad to control Anolis lizards in 1957.
Trachemys scripta elegans Red-eared Slider Gov. Bermuda factsheet (external link) Periodic trapping in ponds and nature reserves. This species is on the IUCN list of 100 of the world’s worst invasive alien species. Unwanted pet terrapins should be taken to a vet or the Aquarium for euthanasia
Rattus rattus Black Rat Gov. Bermuda factsheet (external link) Regular baiting programme island wide
Rattus norvegicus Brown or Norway Rat Gov. Bermuda factsheet (external link) Regular baiting programme island wide
Mus musculus House Mouse Gov. Bermuda factsheet (external link)
Corvus brachyrhynchos American or Common Crow Gov. Bermuda factsheet (external link) Subject to regular culls
Columba livia Pigeon Gov. Bermuda factsheet (external link) Native birds are being protected by creating artificial burrows and non-native pigeons are being culled. Feral pigeons foul the nest holes used by white-tailed tropicbirds (Longtails) making the nest sites un-useable.
Passer domesticus House Sparrow Gov. Bermuda factsheet (external link) Very numerous, but no control programme in place. Competes for nesting sites with native Bluebirds. Sparrows will kill bluebird chicks and take over the nestbox.
Gallus domesticus Feral Chicken Gov. Bermuda factsheet (external link) Control ongoing.
Euglandina rosea Rosy Wolf Snail Gov. Bermuda factsheet (external link) The local population may have crashed due to lack of prey This species is on the IUCN list of 100 of the world’s worst invasive alien species
Pomacea sp. Apple Snail An escaped or released aquarium species. Present in some freshwater ponds. No active control. This species is on the IUCN list of 100 of the world’s worst invasive alien species
Linepithema humile Argentine Ant Gov. Bermuda factsheet (external link) Ants are generally controlled by commercial pest control companies. This ant is the most common species. This species is on the IUCN list of 100 of the world’s worst invasive alien species
Pheidole megacephala Big-headed Ant This species is on the IUCN list of 100 of the world’s worst invasive alien species

Biosecurity

in 2017 a biosecurity gap analysis (PDF) was completed. Bermuda capacity is reasonable for Early Warning and Rapid Response, but weak for Prevention. Risk analysis is done on an ad-hoc basis. Border operations cover both agricultural and livestock issues, as well as invasive plants and marine species and sea shells.

Baseline inventories are good across all taxa. The legal framework is weak overall, with a focus on plant health and animal health issues, and it does not cover species established on-island. There is no national biosecurity strategy or policy, although there are invasive species items in the Biodiversity Strategic Action Plan.

In 2018 a pathway analysis (PDF) was completed. Pathways of introduction to Bermuda are several, with direct access from a number of other countries outside the Caribbean region both by air and sea. There is one international airport, with daily direct flights to US, Canada and the UK. There are no direct flights within the region. Cruise ships depart cruise ports for Bermuda from the Azores, Canada, Guatemala, Panama Canal, and the USA, and within the region from the Bahamas, Cuba, Puerto Rico and USVI. Yachts have only one port of entry, St George’s Harbour, but once they have cleared Immigration and Customs they can take up anchorage anywhere.

Cargo arrives by both ship and plane. Within the region, cargo is mainly flown in from the USA but also arrives on the British Airways flight from the UK. There are at least 6 different companies on Bermuda that are directly involved with the air cargo business. One local company offers air consolidation service from USA, Canada, UK, Europe and the Far East (the latter goes through Dubai before being expedited to Bermuda). Cargo arrives by ship from the USA, with two regularly scheduled weekly callers in addition to car-carriers and special cargo ships, for example unloading gravel and building supplies for the new airport.

Horizon scanning was carried out in 2019, identifying a total of 38 new invasive species of concern which have the potential to arrive within the next 5 – 10 years; read a report on the horizon scanning (PDF).

Thin strip of image show tree trunk and bark