RDI Logo and UWI Crest

Research

Biodiversity in Caroni Swamp

Wetlands are important for the invaluable ecosystem services they provide, yet are threatened worldwide, with half of the World’s wetlands being lost since 1900. An important wetland ecosystem in Trinidad is the Caroni Swamp, located on the western coast. This swamp is also the most heavily impacted in Trinidad, influenced by the capital city and landfill to the north, agricultural development to the east, and the pollution impacts from its namesake river which drains almost one quarter of the surface area of the island. This swamp is dominated by mangrove forests with herbaceous swamp on its eastern boundary, and tidal mudflats scattered within and on the western boundaries of the swamp. This rich mosaic is critically important to the people of Trinidad and Tobago, as well as the organisms which make it home. The Caroni Swamp RDI project afforded us the opportunity to expand our knowledge of this critically important ecosystem. The funding resulted in 24 research projects producing invaluable information which will better inform management.

Research over the past three years focused on the ecological, social and economic importance of the swamp. Camera trapping was used to model the factors which influence the persistence of the Crab-eating Racoon. Transects were used to estimate the densities of the Silky Anteater as well as Ruschberger’s Tree Boa and Caiman. Mist-netting was employed to examine bat community composition in different habitats, and to examine the importance of the swamp to overwintering passerine birds. The swamp was also extensively sampled for fish community composition while mangrove tree community composition along the Blue River, as well as leaf litter fall and decomposition rates were studied. The attitudes and responses of the people of Cacandi to the Swamp were examined, and public participatory GIS was used to not only determine where important resources were derived by people in the swamp, but to indicate the effectiveness of current protection. Finally, the economic value of recreational activity at the swamp, as well as the value of some of the resources and services within it were derived.

There are a number research projects taking place in the Caroni Swamp. Outlined below are just a few.

Participatory GIS for Nesting, Roosting and Feeding habitat sites of the Scarlet Ibis Eudocimus ruber in Caroni Swamp, Trinidad.- Deanna Albert

This project utilizes participation methods along-side Geographic Information Systems (GIS) technology in order to engage a variety of stakeholders; both commu-nity participants as well as experts, in mapping the habitat sites where the Scarlet Ibis nests, roosts and feeds in Caroni Swamp. After a short orientation on the project objectives, map-ping groups are asked to identify areas Scarlet Ibis use on an aerial photograph of the Caroni Swamp with colour coded stickers representative of nesting (yellow), roosting (red) and feeding (blue) sites. Additional data is collected on these identified points through semi-structured interview such as numbers observed, habitat characteristics, prey, predators, etc. Assessment of the effectiveness of existing Protected and Prohibited Areas will be done through comparison of identified points against the boundaries of the Forest Reserve, Wildlife Sanctuaries, and RAMSAR Site. Survey data would be used to determine the degree of overlap between local and expert knowledge collected through mapping exercises. It is expected that data collected from this project can facilitate better man-agement planning for PNAs within Caroni Swamp and be used as a foundation for further studies focused on the Scarlet Ibis within Caroni Swamp or along its wider habitat extent along the wetlands of the west coast of Trinidad. For more information please download .pdf document here

Patch Occupancy of Crab-eating Raccoons in the Caroni Swamp, Trinidad - Laura Baboolal

There is still little known about the Crab-eating Raccoon, Procyon cancrivorus (Cuvier, 1798) due its nocturnal be-haviour and its elusive conduct. It is a carnivorous mammal that can be found throughout Central and South America and also inhabits the island of Trinidad (Zeveloff 2002). The study focused on whether or not environmental factors influence the patch occupancy of the crab-eating raccoon in the Caroni Swamp, Trinidad. For more information please download .pdf document here

Investigating and Evaluating the population Dynamics of Ucides cordatus (Hairy Crab) in the Caroni Swamp, Trinidad and Tobago - Waisea Bolatolu

The land crab Ucides cordatus (Linnaeus, 1763) is a semi-terrestrial species that is common to Neotropical mangrove forests; it is an important resource for the artisanal fisheries. This paper aims to evaluate the population structure and density of U. cordatus in the Caroni swamp Trinidad using field survey and social survey. For more information please download .pdf document here

Inventory, densities and distribution of benthic macro-invertebrates along the Blue River in the Caroni Swamp, Trinidad - Fritzner Agrossous

During April-May 2014, sampling was carried out in the Blue River in the Caroni Swamp, Trinidad to compare the spatial distribution of benthic macro-invertebrates in relation to environmental variables and also to come up with an index of disturbance for each selected site. For more information please download .pdf document here

Population status of the Blue Land Crab, Cardisoma guanhumi, in the Caroni Swamp, Trinidad and Tobago - Keimraj Sookhoo

The Blue Land Crab is a semi-terrestrial species that is found in neo-tropical regions such as the Caribbean and the Americas. It is commercially harvested in countries such as Venezue-la, Puerto Rico, the Bahamas and Brazil. This species inhabits coastal envi-ronments where it lives in burrows above the high tide line. The Blue Land Crab is an important member of estuarine ecosystems where they help shape the composition of plant com-munities through its predation on seeds and seedlings. They also contrib-ute to nutrient recycling, and its burrows facilitate the transportation of water, minerals and oxygen. Recent research, however, has shown that the Blue Land Crab is over-exploited and endangered in places such as Puerto Rico, Venezuela and the Bahamas. The Blue Land Crab is currently on a National List of Threatened and Overexploited Species in Brazil. The status of the species in Trinidad and Tobago, however, is unknown since no official data exists on its population structure and distribution. Consequently, this research was undertaken with the purpose of assessing the population status of this species at the Caroni Swamp where it has been harvested for decades. For more information please download .pdf document here

The impact of water quality on root macrofauna succession in the Caroni Swamp, Trinidad - Errin Chong

Within the mangrove system macrofauna are a vital part of the mangrove food web and are influential in the energy flow within the mangrove ecosystem (Nordhaus, et al. 2009). The organisms that colonize and grow on mangrove roots are referred to as epibionts (Wahl 1989). Epibionts typically settle and grow on any living, solid bare surface in maritime ecosystems (Wahl 1989). In man-groves, littoral mangrove roots are the sole local solid area that is not impacted by significant sedimentation and repre-sent the model habitat for algal and in-vertebrate epibionts (Ellison and Farns-worth 1992). Root macrofauna communities are impacted by abiotic factors such as temperature, salinity, dissolved oxygen, pH, nitrates and phosphates. Water quality in the mangrove ecosystem can have impacts on the macrofauna which exist, impacts including the types and number of macrofauna that occur at a given area. Macrofaunal assemblages are one of the most significant indicators of ecological health in coastal and estuarine environments (Vazirizadeh and Iman 2011). For more information please download .pdf document here

Decomposition of Mangrove Leaves along the Blue River, Caroni Swamp, Trinidad- Mary Tahu

Mangroves are tropical marine plants which are regarded as productive terres-trial ecosystems worldwide (Lacerda et al. 2002). About 50 percent of net pri-mary productions found in mangroves are being exported as organic matter to the ocean (Robertson and Alongi 1995). Mangrove leaves are the biggest part of the primary litter production that are available to consumers and have a significant contribution towards the coastal food chain (Dewiyanti 2010). Identifying decomposition rates of mangrove leaves is important in understanding how organic detritus and nutrients can enrich coastal seas. Leaf decomposition rates in mangroves in Trinidad have never been studied hence the research thesis investigates the decomposition rates of mangrove leaves in Trinidad particularly the decomposition rate of Rhizophora mangle, Laguncularia racemosa and Avicen-na germinans. Leaves were investigates along the Blue River, Caroni Swamp. The objectives of the study were to 1) investigate the rate of decomposition of the three (3) species at six different sites and 2) determine if there is any positive correlation between remaining leaf litter and physico-chemical parameters e.g. salinity, dissolved oxygen, tempera-ture, electrical conductivity and pH. For more information please download .pdf document here

An Economic Valuation of the Recreational Resources at the Caroni Swamp Bird Sanctuary. - Paul Mackoon

This study was conducted to estimate the domestic access value of the recreational resources at the Caroni Swamp Bird Sanctuary. Decisions with respect to protecting species, communities and ecosystems often come down to monetary arguments: How much will this initiative cost and how much is it worth? Environmental economics looks at the interaction between ecological and economic systems in order to create methods to value biodiversity and create sustainability. For more information please download .pdf document here

Mist Netting Survey of Overwintering Migrant Songbirds in the Caroni Swamp, Trinidad.- Kareena Manickchan

The Caroni Swamp has a rich avifaunal diversity with 157 species of resident and migrant birds being recorded in this wetland by ornithologist Richard ffrench (Cuffy 2002). Nearctic-neotropical migratory songbirds refer to passerines (perching birds) that breed in the temperate zone but spend the winter in the tropics (Studds and Marra 2005). Trinidad is located along a main migration pathway from North America to South America and several species of migratory songbirds have been recorded from September to April (ffrench 1991). However, relatively little is known about the migrant songbird population of the Caroni Swamp. Therefore the primary objective of this study is to investigate the migrant songbird population of the northern Caroni Swamp by conducting an extensive mist netting survey during the overwintering period. For more information please download .pdf document here

The Dynamics of the Caroni Swamp Nursery Habitat for Commercial Fish- Guy Marley

One of the greatest values of mangrove forests is that they providenursery habitat for commercially important juvenile fish that may later enter coastal and offshore fisheries, and coral reefs. The dense root structure of mangrove trees retains free-floating fish larvae, provides refuge for young fish, shelter against predation, and a surface for algae to grow on that forms the base of ecosystem food webs.

The fish community of the Caroni Swamp however has rarely been studied, with only one published account in 1970, and two studies performed since. Many areas remain unsurveyed and substantial changes may have occurred since previous studies. We also have littleunderstanding of theimportance the Caroni Swamp has in supporting fisheries in the Gulf of Paria, andhow the features of theCaroni translate to its success as a nursery ground for valuable fish. Answering these questions is pivotal in understanding whetherchanges in the Caroni Swamp ecosystem may have a knock-oneffect toimpact fish stocks in the GulfodfParia.These fisheries are integral to the culture of coastal communities in Trinidad and Tobago, and provide jobs and food to thousands of people. For more information please download .pdf document here

Local Community Use of the Caroni Swamp: Use, Attitudes and Perceptions - Aditi Thanoo

Restricting use and access of protected areas can lead to local people holding negative attitudes towards protected areas and violating regulations to illegally use protected areas (Allendorf et al. 2012). Negative attitudes can affect local perceptions of any future policy action and management strategies. In this regard, one way to improve protected area management is to develop an understanding of local peopleís resource use, attitudes and perceptions, and underlying causative factors (Chandool 2007; Allendorf et al. 2012). For more information please download .pdf document here

Habitat use by the Crab-eating Raccoon, Proycon cancrivorus, in the Caroni Swamp, Trinidad - Danielle Lewis

The aim of the study is to investigate occupancy of the crab-eating raccoon population within mangrove habitats on selected island areas of the Caroni Swamp over a four (4) month period. For the purpose of this study camera traps will be used for animal trapping at random locations within the terrestrial area of the Caroni Swamp and habitat surveys will be conducted at the camera traps sites. Camera traps are a non-invasive sampling methodology which poses a low risk of environmental disturbance to animals in an area (Rowcliffe et al. 2008, 108). For more information please download .pdf document here

Bat Diversity in the Caroni Swamp - Rachel Campbell

Bats in the Neotropics are ecologically important because they aid in the dispersion of seeds, pollination of flowers and help to control the insect population. Bats have a variety of diets which include: insects, small vertebrates, vertebrate blood, fruit and nectar. In Trinidad and Tobago, the mammalian fauna comprises almost 70 species of bats which belong to 9 families (Goodwin and Greenhall, 1961; Clarke, Rostant, and Racey, 2005). There is little known about the composition of the bat fauna in the Caroni Swamp. It is therefore important that the chiropteran fauna in this area be documented and monitored since there is the potential for alterations to the swamp and its surrounding areas to affect the welfare of bat species. For more information please download .pdf document here

Mangrove Forest Structure and Composition with a focus on the Black Mangrove in the Caroni Swamp - Richmond Basant

Mangrove forests appear among the most productive ecosystems on earth providing important goods and services to tropical coastal populations (Fontalvo-Herazo 2011). Mangroves are specially adapted plants capable of surviving in intertidal regions under brackish conditions (Kumara et. al. 2010). Effective mangrove conservation measures should be implemented based on knowledge of species type, abundance, health status and environmental conditions. The purpose of my project is to obtain similar information for the black mangrove in the Caroni Swamp. Baseline data for the black mangrove (Avicennia germinans (L.) Stearn and A. schauriana Stapf & Leechman ex Moldenke) would be collected in the Caroni Swamp as no recent information has been published. Basal area and seedling density would be calculated using diameter at breast height (DBH) and seedling counts respectively. For more information please download .pdf document here

Leaf litter deposition rates of three mangrove tree species in the Caroni Swamp, Trinidad W.I. - Kirby Harripersad

Leaf litter fall in the mangrove swamp represents a significant portion of the components of the mangrove production at the primary level. It may be useful to carry out studies on the rates of this litter fall since they can be indicators of a stressful environment. Mangrove productivity can indicate soil fertility, presence of sulfides, less than optimum soil salinities, changes in temperature and forest structure development. Litter fall rate may be related to canopy cover which represents stand biomass and thus the forest’s productivity and health. This reflects the swamp’s ability to preserve the biodiversity and wetland functions. Estimating leaf fall and litter deposition rates can also gauge the mangrove’s response to climate change since litter fall production is influenced by solar radiation, temperature and rainfall. For more information please download .pdf document here

Passerine bird habitat selection in the Caroni Swamp - Rachel Boodoo

The Caroni Swamp is the largest wetland on the west coast of Trinidad (Cuffy, 2002) and the largest mangrove forest in Trinidad and Tobago (Juman and Ramsewak, 2011 and White, 2008). Covering an area of approximately 6,125 ha the Swamp consists of about 60% of the island’s mangrove. Previous studies have recorded between 138 and 157 avian species (Cuffy, 2002), indicating the swamp’s significance as an important habitat for avian species. Birds can indicate the integrity of landscapes such as wetlands (U.S. EPA, 2002) and the determination of habitat use is important for the conservation of bird species (Chandler, 2011). Nearctic-neotropical migratory songbirds are passerines (perching birds) which breed in temperate areas; however, they spend the winter in tropical environments (Moore and Woodrey, 1993). Trinidad is located along a main migration pathway between North America to South America and several species of migratory songbirds have been recorded at the Caroni Swamp (Kenefick,et al, 2011). However, relatively little is still known about the migrant songbird population of the Caroni Swamp. As such, this project seeks to build on the existing knowledge of the distribution and abundance of the migratory bird species at and around the Caroni Swamp. For more information please download .pdf document here

Density of the Silky Anteater (Cyclopes didactylus) within the Caroni Swamp - Danya Alexander

The Caroni Swamp is a dynamic wetland ecosystem. It contains about 60% of Trinidadís mangrove forest and is the country’s largest mangrove wetland. The combination of such diverse ecosystems has led to the Caroni Swamp being the home to many species resulting in a rich diversity of flora and fauna. Its support of these species is a direct outcome of the swamp’s production and protective characteristics as an ecosystem, enabling it to provide food and a range of habitats to an array of organisms. The Swamp hosts 3 types of mangrove (red, white and black), over 190 species of birds (Bacon, 1970), various species of fishes and mammals. The silky anteater which is native to the mangrove forest of the Caroni Swamp can be found just below the uppermost canopy. However, few studies have been done on the silky anteater and its density within the swamp. For more information please download .pdf document here

Stand dynamics of Rhizophora mangle in Caroni Swamp - Peter Elvin

The Caroni Swamp is of tremendous value both for its economic resources and the ecological benefits it provides. Some of these benefits include being a nursery and a breeding site for fishes, birds, mammals, crustaceans, reptiles and shellfish; shoreline protection against erosion and the filtration of pollutants. There has been a decline in mangrove forest worldwide in recent decades. Wilkie and Fortuna (2003) indicate that mangrove forest cover has declined from 19.8 million hectares in 1980 to 15.9 million hectares in 1990, dropping to 14.7 million hectares in 2000. There has been loss of mangrove cover at the Caroni Swamp by anthropogenic activities as far back as the 1920’s. These losses include the Cipriani Reclamation Scheme of 1921 -1922 which facilitated rice cultivation and involved hydrological alteration of the swamp (Juman and Ramsewak, 2013); the construction of the Princess Margaret Highway in 1958 which was extended in 1988 and renamed the Uriah Butler Highway (Juman and Ramsewak, 2013); and the construction of the Caroni Arena Reservoir by the Water and Sewerage Authority to improve the water supply to the population of Trinidad. For more information please download .pdf document here

Public Participatory GIS for traditional uses of the Caroni Swamp - Reisha Boodram

The Caroni Swamp is the largest mangrove forest in Trinidad and provides a range of resources which makes it economically important to local people. Uses of the swamp include recreational activities such as sport fishing, birdwatching and photography, and extractive activities such as subsistence or commercial fishing, oyster harvesting and crab harvesting (Bacon, 1968; 1993; Juman, Bacon and Gerald, 2002). The swamp was declared a Ramsar site in 2005 in order to protect its rich biodiversity including many threatened species, and to practice sustainable use of its abundant natural resources (Juman and Ramsewak, 2013). Prior to this, in 1987 a large portion of the swamp, bounded by the Blue River to the north and the Madame Espagnol River to the south, was designated a Prohibited Area in order to protect the country’s national bird Eudocimus ruber (Linnaeus, 1758), the Scarlet Ibis. This ban resulted in a significant decrease in legal resource use within the swamp (Juman, Bacon and Gerald, 2002). For more information please download .pdf document here

Spatial Distribution, Relative Abundance and Habitat Use of Shorebirds in the Caroni Swamp, Caroni Rice Fields and Orange Valley, Trinidad - Hema David

Shorebirds are a varied group of wading birds in the order Charadriiformes (suborder - Charadrii) (O’Brien, et.al., 2006 and Colwell, 2010). They are distributed nearly throughout the world, and many of them are long distance migrants (O’Brien et.al., 2006), travelling between their breeding and wintering grounds (Long and Ralph, 2001). As such, their flight is intermittent, requiring stops at intermediate sites to accumulate sufficient energy sources for the journey (Buler et al., 2007). The Caribbean is a stopover site for Nearctic migrants, being located between their breeding grounds in North America and their wintering grounds in South America (ebird, 2013). While several species of shorebirds which occur worldwide are listed as ’least concern’ by the ICUN Red List of Threatened Species, most are thought to be declining or have unknown population trends (IUCN, 2013). This suggests the need for additional research on their population trends, identification of potential threats facing these species and recommended conservation measures (IUCN, 2013). This is particularly important considering the range of anthropogenic threats, such as coastal development, conversion of wetlands into agriculture, and pollution, currently affecting worldwide shorebird populations (Sutherland, W.J. et al., 2012). For more information please download .pdf document here

Impact of environmental stressors on mangrove physiology - comparison of Caroni Swamp, Caroni River & Point Lisas - Natalie Edghill

Despite recognition as one of the earth’s most important ecosystems, wetlands continue to disappear from the Earth’s surface (Gibbes et al, 2009). Comparable to the 50% lost globally are the losses of wetlands in Trinidad and Tobago (World Resources Institute, 1996; Juman, 2010). Since 1787 the total recorded losses exceed 1,300 hectares (more than 50%) with the remaining mangroves under stress due to population, urban and industrial growth (Juman, 2010). Environmental stressors that have particular relevance to mangroves are fluctuations in salinity and the over accumulation of toxins (Gibbes et al, 2009). The Rhizophora mangle (L.) (red mangrove) has been found in previous studies to be negatively impacted by a continuously fluctuating salinity level as compared to areas in which the salinity was more consistent (Biber, 2006). The toxicity of heavy metals as well as their persistence and bioaccumulation in the food chain makes them significant environmental pollutants (Defew et al, 2005). Although capable of filtering toxins, wetlands have a limit on the amount they can absorb before negative impacts begin taking effect (Davies & Claridge, 1993). For more information please download .pdf document here