New records of plants for San Andres and Old Providence islands (International Biosphere Reserve Seaflower ),

: Fifty seven new records of vascular plants are reported for the Archipelago of San Andres and Old Providence, part of the International Biosphere Reserve Seaflower . Of these, about 81% have been introduced for agriculture or ornamental purpose. With these introductions, we report ten new families and 30 new genera for the Archipelago. The possible impacts of some of these introductions are discussed.


Introduction
The archipelago of San Andres, Old Providence and Sainte Cataline islands is located about 200 km off the coast of Nicaragua and due to its vicinity with the Central American continental platform, the vascular flora has a higher affinity with the flora of Central America and Northern South America, compared to the Antillean flora (Lowy 2000).
The island vegetation is classified as transitional, with elements of both dry forest and wet tropical forest (González at al. 1995;Lowy 2000). Due to the high population density, the natural vegetation on San Andres Island has been completely transformed, while on Old Providence Island the original vegetation is still present on the top of the hill (the Peak, Marquez et al. 2006).
The flora of the Archipelago has not been extensively studied. Díaz and Lowy (1992) reported 374 species of vascular plants (366 angiosperms and 7 pteridophytes). Later, Lowy (2000) updated all the botanical information available for the islands, including reports (e.g. Barriga 1969;González et al. 1995) and herbarium specimens, registering a total of 409 species of vascular plants, 77% of which were considered native, and the other 23% introduced.
More recently, Tobar and Gavio (2011) reported the presence of the invasive Pteridium caudatum on Old Providence Island.
Introduced plants are an important component of the actual flora of most countries (Chacón and Saborío 2006), and may cause extensive damage (Mack and Lonsdale 2000). Particularly, introduced species are the most important threat for native species in oceanic islands (Chacón and Saborío 2006).
To contribute to the knowledge of the vascular flora of the International Biosphere Reserve, we carried out an inventory of species not previously reported for the islands. All species have been introduced for agricultural or ornamental purposes. The possible impact of some of these species is discussed. Abstract: Fifty seven new records of vascular plants are reported for the Archipelago of San Andres and Old Providence, part of the International Biosphere Reserve Seaflower. Of these, about 81% have been introduced for agriculture or ornamental purpose. With these introductions, we report ten new families and 30 new genera for the Archipelago. The possible impacts of some of these introductions are discussed.
New records of plants for San Andres and Old Providence islands (International Biosphere Reserve Seaflower), Caribbean Colombia these, ten families and thirty genera are reported for the first time from the islands ( Table 3). All species encountered have a wide tropical and subtropical distribution, and have been introduced for ornamental and agricultural purposes. While 81% of the species listed herein are still confined to greenhouses, backyards and gardens, the other 19% of the new records are naturalised and often escaped into the surrounding areas.
With this study, the percentage of introduced plant species in the International Biosphere Reserve increases to 30%, from the 23% reported by Lowy (2000). The majority of the taxa newly reported have ornamental use (Table 2). Of these, X. sagittifolium, C. maxina, M. x paradisiaca, C. lanatus, A. macrorrhizos, C. melo, T. divaricata, C.warscewiczii, P. ebenea and S. podophyllum have been observed in wild settings on the islands.
Among the species reported, two may become a possible nuisance, due to its invasive behaviour reported in other regions. S. podophyllum (Abrecht et al. 2003) is a species which is difficult to eradicate and tends to expand rapidly at the expense of other species because it has an epiphytical growth form that may suffocate native species. S. podophyllum has been observed in several parts of San Andres Island, in the wild, completely covering other plants.
Casuarina equisetifolia is an invasive tree native to Southeast Asia, Australia and southern Pacific islands to Tahiti and Samoa. Its non-native range now extends to North and Central America, much of the Caribbean as well as islands in the northern Pacific and Indian Oceans. It is thought to be one of the most common tree species on beaches in the tropics (Wheeler et al. 2011). If Casuarina expands, it may alter the habitat of infested areas, inhibiting native plants with rapid growth, dense coverage, and thick litter accumulation (Hammerton, 2001). Casuarina is thought to promote beach erosion (Austin 1978;Deaton 1994;Hammerton 2001), reduce populations of small mammals (Mazzotti et al. 1981), and interfere with the nesting of  Duppy Gully (DG) 4 School Cajasai (CS) 5 Sarie Bay (SB) 6 Airport surroundings (ARP) 7 School Sagrada familia (CSF) 8 Avenida 20 de Julio (A20J) 9 Parque Simón Bolívar (PSB) 10 La Loma diagonal San Francisco Church (LLR ) 11 Center (CEN) 12 New Point Mall (CNP) 13 Los Almendros (BLA) 14 Elsy Bar (SEB) 15 Simpson Well (BSW) 16 Vietnam (BVC) 17 School Modelo Adventista (CMA) 18 Vía San Luis in front of basketball stadium (VSL) 19 Juan XXIII (J23) 23 Botanical Garden (JBU)

Number Name and Abbreviation 15
Agua Dulce (ADP) 21 Surroundings of the catholic church María Inmaculada (IMI) 22 The peak (PEP)  endangered sea turtles (Schmid et al. 2008). Planted along beaches and near homes for protection against wind, the trees are among the first to fall during high winds because of their great height and shallow roots (Schmid et al. 2008;Wheeler et al. 2011). Its wood is susceptible to termites, and if planted close to traditional wooden houses may accelerate their deterioration. The species Allamanda blanchetii, Aglaonema commutatum and Cnidoscolus chayamansa are toxic if consumed, while Allamanda blanchetii produces a latex which may irritate the skin upon contact.
As for the highly invasive and cancirogenic fern Pteridium caudatum, reported recently for Old Providence (Tobar and Gavio 2011), all the species registered here have been voluntarily introduced by the inhabitants of the islands. It is necessary to improve environmental education in the islands and explain the potential risks of introduced species to the population, to avoid negative impacts on the native flora of the archipelago. Small islands are more susceptible to invasive species, and particular care should be taken to reduce the introduction of exotic species and mitigate their impact once established.