Management and Biodiversity conservation of outer islands

All of the outer islands of Seychelles (except D’Arros and St Joseph Atoll) are owned by the Seychelles Government, and the majorities are leased to Islands Development Company (IDC), a parastatal formed in 1980 to establish and supervise economic activities on outer islands. An exception is the Aldabra Atoll, a World Heritage Site, which is being managed by the Seychelles Islands Foundation (SIF). In 2004 IDC signed a MoU with the Island Conservation Society (ICS) that appoints ICS as conservation advisors on all islands owned by IDC. In 2007, this MoU was strengthened into an agreement endorsed by the Ministry of Environment.

The outer islands of Seychelles make up more than half of the total number of islands within the archipelago. These islands hold nine of the twenty Important Bird Areas (IBAs) of Seychelles, vital Green turtle nesting beaches and other native biodiversity but mostly large concentrations of seabirds. However due to their remoteness our scientific knowledge is incomplete. ICS has started coordinating research programs to fill the gaps, however the data collected have in the past been sporadic due to limited access to these islands not only as a result of piracy but also due to logistical constraints.

Since the decline of agricultural activities of outer islands, IDC has shifted its economic activities, and has recognised the importance and benefits of maintaining the rich marine and terrestrial biodiversity. Furthermore, all developers on IDC islands, prior to initiating development, are required to sign an agreement stating that they will create a trust fund which will finance conservation management of the island. These agreements are especially important during a time when climate change and increased tourism development threaten marine and terrestrial habitats, and ICS’s involvement ensures the protection and conservation of habitats which could otherwise be lost.

BIODIVERSITY IN SOME OF THE OUTER ISLANDS

South and Goëlettes Island (Farquhar)

South & Goëlettes Islands, despite being dominated by coconut palms, have high diversity of native beach crest vegetation, including Scaevola sericea, Suriana maritima, Guettarda speciosa and Tournefourtia argentea. Relatively large areas of mangrove forest exist on both islands. Biodiversity is relative high including native species within families of mangrove crabs, mudskippers, crustaceans, arthropods and other invertebrates, water-birds and other aquatic organisms. Between 10 and 40 pairs of Black-napped Tern (Sterna Sumatrana) (protected in the Seychelles only at Aldabra) breed on Goëlettes making it one of only 6 known breeding sites for this species in Seychelles, which hosts the entire known population of the African region. Goëlettes also supports 15–20 pairs of Roseate Tern (Sterna dougalii) and a large Sooty Tern (Sterna fuscata) colony (200,000–400,000 pairs) during the south-east monsoon. Other significant breeding seabird species include Red-footed Booby (Sula sula) (50–70 pairs), and Brown Noddy (Anous stolidus) (10 000 pairs). South island supports significant colonies of seabirds as well as concentrations of Green turtles. The combined biodiversity richness and importance of both islands are important for the long-term conservation of Seychelles biodiversity as they provide a corridor between the outer and inner islands for migratory species and hence deserve to be considered as such.

Grand & Petite Polyte and Grande Ile (Cosmoledo)

Grand Polyte (21ha), Petit Polyte (1ha) and Grande Ile (142ha) within the Cosmoledo atoll are three important seabirds and sea turtles nesting sites. Important concentrations of Arenaria interpres (Turnstone) (up to 700 individuals) and Dromas ardeola (Crab Plover) (up to 1500 individuals), Puffinus pacificus (Wedge-tailed shearwater) 16000 individuals, the rare and endangered Sula leucogaster (Brown Booby), Fregata minor  (Greater Frigate-bird) 2-4 pairs and  Sterna bergii (Crested Tern) (around 200 pairs) are recorded at Cosmoledo.  It is also the only and largest breeding colony in this region for sooty tern.  Resident land-birds include three endemic Seychelles races, the white-eye, the sunbird, and the turtle dove. The Madagascar Cisticola is common on most of the islands and occurs only on Cosmoledo and Astove in Seychelles. The three islands combined holds Seychelles largest colonies of Sula sula (Red Footed Booby)), and Sula dactylatra, both of which have suffered drastic decline in numbers elsewhere in the Indian Ocean, including extinction on certain islands within the archipelago.

The vegetation is typical of coralline islands flora and mirror that of Aldabra, hence dominated along the coast by salt-resistant Pemphis acidula, (Dwa damann) but with some extensive open grassy areas that provide ideal habitats for three ground- nesting seabird species not present on Aldabra (Sula dactylatra, (Masked Booby), Sula leucogaster (Brown Booby) and Sterna fuscata (Sooty tern). Grande Ile used to have a human settlement who was engaged mostly in agriculture, fishing, and the exploitation of seabirds and their eggs as well as sea turtles. The atoll is now abandoned but receives frequent visits from boats within Seychelles and from Comoros for illegal poaching of seabirds, eggs and turtles.

Desnoeufs Island

Desnoeufs Island is a 35hectares low lying coralline island within the Amirantes group and lying approximately 325km Southwest off Mahe Island. The Department of Environment has an ongoing seabird monitoring programme during the South-East Monsoon to control and police Sooty Tern (Sterna fuscata) egg harvest. Half of the island is dedicated to conservation while eggs within the other half are harvested. The island offers safe breeding ground for the largest colony of Sooty tern (>1million individuals) in the Seychelles. Although there are no endemic species, there is however significant number of Wedge-tailed shearwater (Puffinus pacificus), Audubon’s Shearwater (P. Iherminieri), Masked Boobies (Fou Zenero) and a few pairs of Brown Noddies (Annous stolidus). The island is therefore a haven for seabird species that reproduce within the archipelago. Vegetation community is dominated by Stenotaphrum micranthum. Large areas of a sheltered mixed herb community including the white flowered Catharanthus roseus (Madagascar periwinkle) and Acalypha indica, mixed with S. jamaicensis and Ipomoea pes-caprae. Other plants observed included Cocos nucifera (coconut palm), Gossypium hirsutum (cotton), Morinda citrifolia (Indian mulberry), Desmanthus virgatus, Colubrina asiatica, Hibiscus tiliaceus and Nicotiana tabacum (tobacco).

Saint Francois & Bijoutier Islands (Alphonse group)

The Alphonse Group falls under the jurisdiction of the Island Conservation Society (ICS), a Seychelles based conservation NGO. The ICS, in partnership with the Island Development Company (IDC), is in charge of conservation in the outer islands. Strict restrictions are in place limiting the number of fly-fishermen at Saint Francois at any one time, only barbless hooks are used, and all fishing is ‘catch and release’. By the late 1800s, Saint Francois was developed as coconut plantations, however, large areas of native broad-leaf forest have since naturally re-established themselves. Bijoutier and Saint Francois meets IBA criteria for four species of congregatory water-birds: Black-napped Tern, Saunders’ Tern (Sterna saundersi), Crab Plover and Ruddy Turnstone (Arenaria interpres). The proposed PA incorporates important nesting sites for Green Turtles (Chelonia mydas) and Hawksbill Turtles (Eretmochelys imbricata). Saint Francois may be a site of global importance as a wintering ground for Dromas ardeola (Crab Plover); up to 1,500 birds (3% of the known world population) have been recorded. Saint Francois is hosts to a large number and diversity of crabs, including Callinectes sapidus (Blue Crab) and the world largest crab, Birgus latro (Coconut or Robber Crab).

Birds which have been observed at Saint Francois include 1,000-1,500 pairs of Gygis alba (white Tern), Anous stolidus (Brown or Common Noddy) and Fregata minor (Greater Frigatebird). In February 2008, 11 breeding pairs of Sterna sumatrana (Black-naped Tern) were recorded at Saint Francois Ardea cinerea (Grey Heron) frequently patrol the reef-flats in search of fish when the tide recedes. Dromas ardeola (Crab Plover), a wader that is especially adapted for eating crabs, is also found and Saint Francois may be a site of global importance as a wintering ground. Up to 1,500 birds (3% of the known world population) have been recorded at Saint Francois, and nowhere else in the world can such a high proportion of ‘migratory species be found wintering so far from a continental landmass. Saint Francois hosts to a large number and diversity of crabs, including Callinectes sapidus (Blue Crab) and the world largest crab, Birgus latro (Coconut or Robber Crab).

Saint Francois was included in the proposal for the First Inventory of Important Bird Areas, adopted at a national workshop in 1998 but removed from the final list as it was considered that more data were needed. Since then, surveys by the Island Conservation Society (ICS) have confirmed Saint Francois meets IBA criteria for four species of congregatory water-birds: Black-napped Tern (Sterna sumatrana), Saunders’ Tern (Sterna saundersi), Crab Plover and Ruddy Turnstone (Arenaria interpres). The proposed PA incorporates important nesting sites for Green Turtles (Chelonia mydas) and Hawksbill Turtles (Eretmochelys imbricata). The inland lagoons are also important foraging habitat for both turtle species as well as important feeding habitats for immature sea turtles in the western Indian Ocean. Poaching is also of concern on Saint Francois: in 2001, the remains of 111 slaughtered Hawksbill Turtles were found on the island (report in The Nation, 19 Oct 2001).

Saint Francois is encircled by a wide sandy beach. The surrounding reef platform, probably an in-filled lagoon is still present to the southeast of the island, is almost completely covered with low to high density sea-grass (Thalassodendron ciliatum and Thalassia hemprichii), with the macro-algae Halimeda sp. and Microdictyon sp. also being present. There is no well-developed reef crest; rather, the fore-reef is characterized by extensive areas of fore-reef sand. Particularly on the western margin, and concentric bands of reef, with localised strips of high density sea-grass, merging into more continuous coral coverage in deeper water. Goreau described a rocky slope at the south-eastern reef margin which, prior to bleaching in 1998, was dominated to water depths of 20m by Acroporid corals with some colonies of Heliopora coerulea, Pocillopora verrucosa and other species. In deeper water, at least half the rocky substrate was encrusted with coralline algae. At 16-25 m depth on the western fore-reef slope of Bijoutier, large reef buttresses support gorgonian sea fans and Tubastrea micrantha, indicating high current flow which attracts large schools of fish and mega-fauna. Surveys in March 2003 showed there to be 27% live coral cover at a depth of 17m on this western fore-reef slope, with Porites and Pocillopora cover combined accounting for half the coral community present.

Assumption Island

The island was uninhabited until June 1908, when a guano-mining settlement was established on the northwest coast. Between 1926 and 1945, 161, 000 tons of guano was exported. This has led to major environmental catastrophe especially changes in seabird composition and density. The Abbott’s booby (Sula abbotti) is now extinct and breeds only on Christmas Island. The booby breeding colonies over the northern half of the island have disappeared. The endemic rail Dryolimma cuvieri abbotti and the endemic subspecies of turtledove (Streptopelia picturata) are now extinct. On the other hand, the endemic sunbird (Nectarinia sovimanga abbotti), the crow (Corvus albus) and many migrants and vagrants are still present and very common. The only native mammal at Assumption is an insectivorous bat Taphozous mauritianus while the geckos Phelsuma abbotti abbotti and Hemidactylus mercatorius, and the skink Ablepharus boutonii, are also native. 18 species of flowering plants are native while three are endemic to Assumption. Assumption is also very rich in invertebrate’s fauna similar to the inverts communities of Aldabra.

Aldabra

Aldabra is the only place where a wide number of species can be seen, mostly the Aldabran endemic land birds. Aldabra is also the world’s pre-eminent place for giant tortoises, even though the main population is not open to tourism, more giant tortoises can be seen on the accessible parts of Aldabra then on anywhere else on earth. Aldabra atoll is a strict nature reserve famous for its huge frigate bird colonies, seabirds and land birds.

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