Main Ridge, Tobago (20672)
Trinidad and Tobago, Caribbean

Site overview

KBA status: confirmed

Year of last assessment: 2007

National site name: Main Ridge, Tobago

Central coordinates: Latitude: 11.2812, Longitude: -60.6175

System: terrestrial

Elevation (m): 0 to 549

Area of KBA (km²): 39.82523

Protected area coverage (%): 38.43

KBA classification: Global/Regional TBD

Legacy site: Yes

Site details

Site description: The Main Ridge in Tobago forms the “backbone” of the northeastern half of the island. There is no well defined peak but the highest points are 549 m near the mid point of the ridge and 541m at Pigeon Peak near the northern end. One main road crosses the ridge but there is no habitation. The Main Ridge has been formally protected since 1765 by the designation of the Main Ridge Forest Reserve. The reserve is surrounded by forested or agricultural lands, many of which have been abandoned and have reverted to secondary forest.

Rationale for qualifying as KBA: This site qualifies as a Key Biodiversity Area of international significance because it meets one or more previously established criteria and thresholds for identifying sites of biodiversity importance (including Important Bird and Biodiversity Areas, Alliance for Zero Extinction sites, and Key Biodiversity Areas)

Additional biodiversity: The Main Ridge provides habitat for four restricted range species three of which are endemic subspecies. These include the White-tailed Sabrewing, Venezuelan Flycatcher, The Main Ridge provides habitat for four restricted range species three of which are endemic subspecies. These include the White-tailed Sabrewing, Venezuelan Flycatcher, Rufous-vented Chachalaca and Copper-rumped Hummingbird. The ridge also provided habitat for a further 17 endemic sub-species. The Tobago populations of White-tailed Sabrewing and Blue-Backed Manakins were thought to have been exterminated by hurricane Flora in 1963. Populations have now recovered and displaying Blue-backed Manakins are one of the main attractions to visitors to the forests of Tobago. Non-bird biodiversity: While Tobago has not been particularly isolated a number of endemic forms have been recognized. The frogs Manophryne olmonae, and Eleutherodactylus charlotvillensis are limited to Tobago. Eleutherodactylus urichi is limited to Trinidad and Tobago, and the Tobago populations of Hyalinobatrachium orientale are considered to be the subspecies H.o. tobagoensis. Among the lizards, the Ocellated Gecko Gonatodes ocellatus is a Tobago endemic as is the subspecies of Bachia heteropa, B.h. alleni . One endemic snake species Erythrolamprus ocellatus, and two subspecies Liophis reginae ssp. and Mastigodryas boddaerti dunni are currently only known from Tobago. There are 16 endemic plants listed from Tobago, most of which are likely to occur within the boundary of the Main Ridge Forest Reserve.

Delineation rationale: Mark has the shapefiles.

Habitats

Summary of habitats in KBA: Along the Main Ridge soil moisture is adequate even in the dry season to support Rain Forest, of which three types have been recognized. Lowland Rain Forest, Lower Montane Rain Forest and Xerophytic Rain Forest. The predominant vegetation is Lower Montane Rain Forest of the Byrsonima spicata - Ternstroemia oligostemon (Rosewood-Redwood) type. In its climax state the canopy is at 12-30m with abundant Rosewood, Byrsonima spicata, Wild Cocoa Licania biglandulosa, Redwood, Ternstroemia oligostemon, Devilwood Eschweilera decolorans and Lionwood Sloanea trinitensis . The lower storey occurred from 3-12m with abundant Euterpe palms, Wild Coffee Styrax glaber and Myrtaceous species. Lowland Rain Forest occurs up to 240m and extends to 360m depending on exposure. While this forest covers much of the lower slopes of the main ridge comparatively little occurs within the Main Ridge Forest Reserve. The forest is characterized by a closed canopy at 35m with two poorly defined lower strata. A middle storey occurs at 12-24m, a lower storey at 3-12m and a ground layer. Abundant species include Crabwood, Carapa guianensis, Angelin Andira inermis, Roseflesh, Hieronyma caribaea and Devilwood, Eschweilera decolorans. Towards the south west of the Main Ridge, soils are of igneous origin, drainage and exposure are high and consequently soil moisture is low despite regular rainfall. Dominant species show adaptations to temporary but not seasonal shortages of water. This vegetation has been classified as Xerophytic Rain Forest. Dominant species include Gooseberry Manikara bidentata, Blue-copper Guettarda scabra, Galba, Calophyllum lucidum, Bayleaf Amomis caryophyllata and Myrtaceae spp. While the forest in Tobago represented a climax state when originally described in 1942, they were devastated by hurricane Flora in 1963 with little or none of the original canopy remaining, especially in exposed areas. The forest has been recovering steadily since but is yet to reach the condition originally described. In 1990 the forest canopy was estimated at “55 ft” with a “dense and impenetrable” under storey. This is in contrast to conditions prior to 1963 when one could walk freely through the forest.

Land use: agriculture | urban/industrial/transport

IUCN Habitat	Coverage %	Habitat detail
Forest	100

Threats

Summary of threats to biodiversity at KBA: The people of Tobago appear to show a general appreciation of their environment which, coupled with the importance of the local eco-tourist industry, will help to curb the threat of hunting and widespread habitat destruction. Hurricanes pose a serious threat, especially given the expected increase in intensity and frequency of hurricanes associated with climate change. Bush fires are common during the dry season and contribute to significant habitat loss.

Additional information