Introduction to ‘guest blog’ (by Shelagh McCartan)
Rosemary Newton is an ecologist with a seed background. She is based at RBG Kew, UK. In her blog, she discusses the prickly challenges of collecting seeds for conservation.
Guest Blog by Rosemary Newton ( Career Development Fellow (Islands) at the Royal Botanic Gardens Kew, UK)
One of the strategic outputs of the Science Strategy of the Royal Botanic Gardens, Kew, is to bank 25% of the world’s plant species by 2020. Kew’s Millennium Seed Bank (MSB) Partnership is working with partners in 80 countries to achieve this target. One of these partners is the National Parks Trust of the Virgin Islands (NPTVI), based on Tortola, one of the British Virgin Islands (BVI) in the Caribbean. The Flora of the West Indies documents approximately 940 seed plant species (including non-native species) recorded from the four largest islands in BVI. The vegetation on the islands comprises mainly tropical dry forest, dry scrub, mesic forest in the higher elevations, salt ponds in low-lying areas and mangrove swamps along the coast. Since 2003, 112 seed collections of 82 plant species have been made by Kew and NPTVI staff from eight of the approximately 60 islands that comprise the BVI archipelago.
In June 2016, Kew’s United Kingdom Overseas Territories (UKOTs) team travelled to the British Virgin Islands to launch a Tropical Important Plant Areas (TIPAs) project, the aim of which is to assess and map TIPAs in the BVI to enable local authorities to prioritise their protection and conservation efforts. Following the workshop which was held at the J.R. O’Neal Botanical Gardens, the UKOTs team and regional collaborators embarked on day trips to previously unexplored areas on the islands of Tortola, Beef Island, Virgin Gorda, Great Tobago and Prickly Pear in search of new, rare and threatened plants and also to map the occurrence of invasive plant species. A new species for the MSB which we were able to collect seed from was the spiny legume Pictetia aculeata, endemic to the Virgin Islands and Puerto Rico.
Tom Heller and Colin Clubbe collecting Pictetia aculeata seed on Beef Island
Many of the plant species on the islands possess spines or thorns, which makes moving through dense vegetation a painstakingly slow process! One species of Cactaceae, Opuntia repens, made an unforgettable impression on the team as we made our way across the island of Great Tobago. Commonly called the jumping cactus, this plant has perfected the art of vegetative reproduction, as segments readily break off from the plant when touched and the barbed spines attach securely to clothing and even the covered skin beneath. We very quickly learned not to try to remove the segments with our bare hands but to carefully flick them away with a stout stick. Although the primary mode of reproduction and dispersal in this species is vegetative, these plants produce very attractive flowers.
The jumping cactus, Opuntia repens, in flower on Great Tobago
An attractive native tree that we encountered and that is widespread across the region is Coccoloba uvifera of the Polygonaceae, locally known as the sea grape. This dioecious plant is useful for coastal dune stabilisation as it is both wind resistant and salt tolerant. It is also an attractive ornamental shrub, with the female plants producing large bunches of edible fruit that are purple when ripe and that are consumed raw, used to make jam or fermented to produce sea grape wine. Unfortunately, we were unable to collect seeds from this species on this trip as the fruits were still green and so not yet ripe. However, the MSB does have a couple of seed collections of this species conserved in the bank from other localities.
Coccoloba uvifera, commonly known as the sea grape, with unripe fruits
Fruits on the islands form an important part of the diet of indigenous iguanas. On the limestone island of Anegada we met up with Kelly Bradley from Fort Worth Zoo, a conservation biologist studying the Critically Endangered Anegada iguana (Cyclura pinguis). This species was reduced to a population of fewer than 300 individuals due to pressures from feral domestic animals, in particular cats, which kill hatchlings and juveniles for food. In 1997 a headstart facility was built to enable conservationists to rear hatchlings in captivity. This facility has been successfully rearing animals until they are large enough to survive alongside cats and can be released back into the wild. Whether the passage of seeds within fruits through the iguana’s gut facilitates seed dispersal and promotes germination or is detrimental to seed viability is still largely unknown. As the iguanas’ range became restricted to Anegada during the last deglaciation, the role of the iguana in recruitment of fruit-bearing plants is being investigated by Kelly and Kew staff member, Martin Hamilton, with NPTVI colleagues.
A juvenile Anegada iguana at the headstart facility
As a relatively new member of the UKOTs team, this field trip was a memorable introduction to the unique flora of BVI and the challenges facing plant conservation in the region. On this trip we were able to collect seed from plant species on Prickly Pear and Beef Island, two new localities for the MSB. In total, 12 collections of eight species new to the MSB were accessioned.
Thanks to Dr Martin Hamilton for organising the logistics, Kelly Bradley for showing us the Anegada iguana headstart facility, and Kew, NPTVI and Puerto Rico colleagues for sharing their knowledge and expertise of the local flora. The BVI TIPAs project is funded by HSBC through the 150th Anniversary Fund and the seed collecting work is funded by the Garfield-Weston Foundation through the Global Tree Seed Bank Project. Regional collaborations and capacity building for NPTVI staff are being made possible through the Darwin Plus funded project [DPLUS030] “Building systems and capacity to monitor and conserve BVI’s flora”.