Ecology of Trinidad and Tobago

Trinidad and Tobago has some of the richest natural communities in the Caribbean. Unlike most of the islands of the Caribbean, Trinidad and Tobago supports a primarily South American flora and fauna. As a result, Trinidad and Tobago is richer in plant and animal species than is the rest of the Caribbean. However, rates of endemism are lower than in the rest of the Caribbean because most of the species in Trinidad and Tobago are also found on the South American mainland.

Plant communities

The standard description of plant communities follows John Beard's work (Beard, 1946). He classified natural vegetation in a hierarchical fashion on the basis of the physiognomy of the dominant trees.

* Seasonal Formations
** Evergreen Seasonal Forest
** Semi-Deciduous Seasonal Forest
** Deciduous Seasonal Forest
* Dry Evergreen Formations
** Littoral Woodland
* Montane Formations
** Lower Montane Forest
** Montane Forest
** Elfin Woodland
* Edaphic Formations
** Mangrove Forest
** Palm Swamp
** Seasonal Swamp Forest
** Seasonal Swamp Savanna
** Herbaceous Swamp

: "See also: Trinidad and Tobago dry forests

Terrestrial animal communities

Mammals

Trinidad and Tobago is home to a little over 100 species of mammals, a large percentage of them being bats (one of them being a fishing bat). Another of the bat species, the Vampire Bat, does not deserve its notorious reputation, as it feeds almost exclusively on non-human blood. Carnivorous mammals include the Ocelot, the Tayra, the Crab-eating Raccoon and the Neotropical River Otter. Large herbivores include the Red Brocket, the Collared Peccary and the highly endangered West Indian Manatee (a few of which persist in the ecologically diverse Nariva Swamp on Trinidad's east coast). The Red Howler Monkey and the White-fronted Capuchin are the country's two native primate species. The Silky Anteater and its relative the Tamandua are two of the most bizarre creatures of Trinidad's forests. Other small to medium sized mammals present include the agouti, the paca, the prehensile-tailed porcupine, the Nine-banded Armadillo and a few species of opossum. A number of small rodents including a species of squirrel are native to the islands. A few Cetacean species (whales and dolphins) including Pilot Whales and Orcas have been known to occur in the seas around Trinidad. Whales were once far more common in Trinidad's Gulf of Paria (which Columbus called Golfo de la Ballena or the Gulf of Whales) but a rigorous whaling industry during the 19th century severely reduced the population of various species that once thrived there. The Indian Mongoose was introduced during colonial times to mainly help to control the population of rats (and possibly to a lesser extent snakes) found on the Trinidad's plantations. The local names (many of which are of French Patois and Native Carib/Arawak origin) for some of the islands' mammalian fauna are listed below:

Birds

468 species of birds have been recorded in Trinidad and Tobago. There are few places in the world where so many birds can be seen in such a small area, and many of them are unique, very rare, or of particular interest. They range from the many species of hummingbird to the primitive cave-dwelling oilbird (that uses sonar to fly in the dark) to the spectacularly beautiful Scarlet Ibis. The islands are within a few miles of Venezuela, and the species are therefore typical of tropical South America. However, the variety is relatively impoverished compared to the mainland, as would be expected with small islands.

The resident breeding birds are augmented in the northern winter by migrants from North America.

Species occur on both islands except where indicated. Tobago has only about half the number of bird species of Trinidad, but 22 birds have occurred only on the smaller island, including 12 breeding species.

: "See also: List of birds of Trinidad and Tobago"

Reptiles and Amphibians

In addition to the snakes (which range in size from some of the world's smallest to the world's largest) which may be seen listed at the link below, Trinidad and Tobago is home to a host of other interesting herpetofuana.

There are a number of lizards ranging in size from just over an inch or two in length to the huge convert|6|ft|m|sing=on long Green Iguana ("Iguana iguana"). The 'so called' Luminous Lizard ("Proctoporus shrevei") makes its home in the mouths of caves and cool stream banks near the summits of Trinidad's 2 highest peaks. The large Tegu ("Tupinambis teguixin") or Matte as it is locally called and the Green Iguana (very common, even in sub-urban areas) are considered delicacies on both Trinidad and Tobago. A number of Anole species may be easily observed, even in sub-urban areas. Other macro-teiids (or whip-tailed lizards) include the common "Ameiva ameiva" (locally called the Zandolie or Ground lizard and common even in sub-urban gardens) and "Cnemindophorus lemniscatus" (most widely seen along Trinidad's east and south coasts and on the islands of Chacachacare and Huevos). There are a number of small colourful diurnal geckos of the genus "Gonatodes" that are present. One of them, "Gonatodes ocellatus" is endemic to Tobago while another, "Gonatodes vittatus" or the 'streak lizard' as it is locally known, is very common and can be seen in most sub-urban and even urban backyards in Trinidad.

Terrapins, tortoises and turtles make their homes on these islands. The giant Leather Backed Turtle, the Hawksbill Turtle, the Loggerhead Turtle, the Olive Ridley Turtle and the Green Sea Turtle are marine species that all nest on the islands' beaches or frequent their coastal waters. The land dwelling yellow-footed Tortoise ("Geochelone denticulata") or Morocoy as it is locally known is threatened by over hunting. The odd mata-mata turtle is known to inhabit the Nariva Swamp. All the turtle species are threatened by rampant illegal hunting activity - in 2007 I passed a shop with at least 5 large turtle shells hanging for sale by Manzanilla beach (a nesting spot for several species).

The Spectacled Caiman ("Caiman crocodilus") which may grow up to about convert|8|ft|m in length shares its habitat in the Nariva Swamp on Trinidad's east coast with the mighty Green Anaconda ("Eunectes murinus"). Caiman are to be found throughout both islands in slow moving fresh or brackish water. The are shy creatures and pose no real threat to humans unless intentionally provoked or approached while nesting. While it was considered that the few records of both the American Crocodile ("Crocodylus acutus") as well as the Orinoco Crocodile ("Crocodylus intermedius") in the waters of Trinidad and Tobago were, for the most part, waifs from mainland South America, there are many reports of both of these species from the Caroni Swamp area and throughout the Caroni basin, some individuals growing up to convert|15|ft|m|abbr=on in length.

A number of frogs and toads inhabit the islands, including the well known huge Marine or Cane Toad ("Bufo marinus") locally known as the Crapaud (pronounced crah-poh) and the tiny, colourful, rare endemic species known as the El Tucuche Golden Tree Frog ("Phyllodytes auratus") found only in the giant epiphitic bromeliads at the summits of Trinidad's two highest peaks. The strangest of all Trinidad's frogs is the highly aquatic Suriname Toad or Pipa Toad ("Pipa pipa"), the tadpoles of which develop in the skin tissue of the mother's back, before bursting out and emerging as miniature replicas of the adult frogs. The two frog species of the genus "Manophryne" (one of which is endemic to Tobago) demonstrate a degree of parental care as the tadpoles are transported on the backs of the adult males before a suitable body of water is found where they may be left to develop. Trinidad is also reputedly home to a Caecilian species (a legless serpentine amphibian that is rarely observed due to its habitat preference) although only one specimen has ever been scientifically documented from Trinidad.

: "See also: List of snakes of Trinidad and Tobago"

Invertebrates

Trinidad and Tobago are extremely rich in neotropical invertebrate fauna. Several hundred species of butterflies (including the brilliant blue Emperor Butterfly "Morpho peleides)" and beetles are to be found on the islands, many in the Tropical Forests. Barcant (1970) lists 617 species of butterfly for the 2 islands of which 123 occur on Tobago. The leaf cutter ant is easily observed, even in urban environments. Soldier ants may be observed in forested areas. The largest specimens of centipedes (over convert|10|in|mm long) may be found particularly in the drier forests of the Northwestern Peninsular of Trinidad (the Chaguaramas Peninsular) as well as the nearby tiny off shore islands. The insect life of Trinidad and Tobago has not been well studied and it is an entomologist's paradise waiting to be discovered, with many species remaining undocumented.

"see also List of Butterflies of Tobago"

Aquatic communities

There are a number of wetland habitats on both Trinidad and Tobago that foster vital aquatic ecosystems.

The Bon Accord Lagoon on Tobago is a vital mangrove habitat and home to a population of Spectacled Caimans as well as a number of wetland bird species.

The Caroni Swamp on the west coast of Trinidad has a fairly high level of salinity (compared to other major wetlands on the island) and is an important breeding habitat for several bird species (including magnificent flocks of Scarlet Ibis (one of the National Birds)) and several marine fishes and invertebrates.

The Nariva Swamp of the east coast is the largest freshwater swamp on Trinidad and has a RAMSAR convention status of Wetland of International Importance. It is home to a vast array of aquatic life, including a small population of West Indian Manatees, green anacondas, caimans, mata mata turtles and suriname toads. The plant community in the swamp include various mangroves, Moriche Palms and Bloodwood Trees. Red bellied macaws (in addition to other parrot species) still forage among the palms in the Nariva Swamp.

There are many rivers and streams throughout the islands, particularly in the Northern Range of Trinidad. The guppy was first described from specimens obtained in the streams of Trinidad.

Marine communities

Trinidad's western and southern coastal waters are highly influenced by the outflow of freshwater from the adjacent Orinoco River of Venezuela which is less than convert|8|mi|km away from Trinidad at the closest point. As such, the waters here are fairly low in salinity and high in sediment/nutrient content and relatively shallow. These facts coupled with the highly sheltered nature of the Gulf of Paria and the Columbus Channel respectively, create ideal breeding/spawning grounds for many marine fishes and invertebrates, including shrimp.

Various 'sporting' fish are present in the waters of both islands and include huge grouper, marlin, barracuda and dolphin-fish. Fish popularly caught and eaten include carite, kingfish and red snapper.

As mentioned in the section above on the reptilian fuana of Trinidad and Tobago, a number of species of marine turtles including the Leather Backed Turtle, the Hawksbill Turtle, the Loggerhead Turtle, the Olive Ridley Turtle and the Green Sea Turtle both live in the waters around and nest on the beaches of both islands.

Whales and dolphins were far more common to Trinidad's waters in earlier times, but the very rigorous whaling industry of the 19th century decimated the population of whales in the Gulf of Paria. Today, dolphins may still be regularly observed, particularly off the shore of the northwestern Chaguaramas peninsular. Pilot whales have been observed to beach themselves on a few occasions during the 1990s and a small pod of killer whales were caught in a fisherman's net during the 1980s.

Whale sharks (the largest of all fishes) have been observed around the oil rigs in the southern part of the Gulf of Paria. Hammerhead sharks are commonly caught by fishermen and shark is considered a delicacy among the human population of both islands.

The waters of Tobago are less affected by the outflow of fresh water from the Orinoco and as such are far more saline and clearer than that of Trinidad. A number of coral reefs are thus able to exist around Tobago, the most famous being the Buccoo Reef. Tobago's reefs are reputedly home to the largest examples of brain coral. Also present are huge and gentle manta rays, impressive moray eels, parrot fish, angel fish and a host of other colourful tropical coral reef species.

References

*Barcant M (1970):"Butterflies of Trinidad and Tobago". Collins, London .
* Beard, J. S. (1946) The natural vegetation of Trinidad. Oxford University Press, Oxford.