Biodiversity

Pelagic plankton diel vertical movement, diversity, and density in relation to nitrate concentration in Bonaire, Dutch Caribbean

Plankton are the base of the marine food web and are studied for a broad range of research relating to diversity and ocean health. These organisms have not been well studied in Bonaire and this study provided a preliminary assessment for the pelagic net plankton movement and diversity. Water samples and plankton tows were collected using a Niskin bottle and 20-micrometer closable plankton net respectively at four depths: 90 m, 60 m, 30 m, and 10 m. The water samples were processed for nitrate concentration and the 5-meter vertical plankton tows were analyzed for plankton abundance using the following categories: diatoms, dinoflagellates, copepods, and other zooplankton. Dinoflagellates displayed diel vertical migration with higher density at 10 m and 30 m during the day and lower density at 10 m and 30 m at night. Simpson’s Diversity Index (SDI) did not show a significant difference in the diversity at 90 m and 10 m during the day or night. Nitrate concentration and plankton density were not found to be correlated. This study created a preliminary assessment for further research into the effects of the lunar cycle, nitrate, and movement of the pelagic net plankton of Bonaire.

This student research was retrieved from Physis: Journal of Marine Science XIX (Spring 2016)19: 28-34 from CIEE Bonaire.

Date
2016
Data type
Other resources
Theme
Research and monitoring
Geographic location
Bonaire
Author

Plants and Lichens of St. Eustatius. A Virtual Herbarium of the New York Botanical Garden

St. Eustatius, also informally known as "Statia" is an 11.8 square mile (30.6 square km) island with about 3,200 permanent inhabitants located off the coast of St. Maarten (go to map from link in banner). English is the official language of the island but Dutch is also taught in schools and is spoken by many Statians.

In January 2008, The New York Botanical Garden, in partnership with the St. Eustatius National Parks Foundation (STENAPA), the Department of Environment and Nature (MINA) of the Netherlands Antilles, and Conservation International, embarked on a project to survey the plants and lichens of Statia. (See photobook from the expedition.)

Although relatively small in size, Statia's topography is covered by several vegetation types with a variety of soil types, ranging from beach forest at sea level to elfin forest on the summit of The Quill, a dormant volcano, at some 600 m elevation. Our goal is to provide illustrated checklists (a virtual museum) of all of the plants and lichens that grow on Statia. Both native and introduced species are included.

To find collections representing species of flowering plants, gymnosperms, ferns, bryophytes, or lichens, you can access the information available for a given group by clicking on the appropriate image on the left hand side of this page.

It is forbidden to pick plants and to remove plants from the island of Statia. All natural history studies must first be approved by the government of The Netherlands. To find out how to obtain permission to collect herbarium specimens, as was done in this study, contact STENAPA. All photographs are copyrighted by the photographer, Carol Gracie, unless otherwise noted. For permission to use the images, contact the photographers. Citizens of Statia have permission to download images from the website for personal or educational purposes.

Date
2009
Data type
Portal
Theme
Research and monitoring
Geographic location
St. Eustatius
Image
Plants and Lichens of St. Eustatius

Plants and Lichens of Saba. A Virtual Herbarium of The New York Botanical Garden.

Saba is a five square mile island with about 1200 permanent inhabitants located off the coast of St. Maarten in the Netherlands Antilles (go to map from link in banner). English is the official language of the island but Dutch is also taught in schools and is spoken by many Sabans.

In February 2006, Conservation International, in conjunction with the Saba Conservation Foundation, embarked on a project to survey the biodiversity of Saba from beneath the sea to the summit of its highest peak, Mt. Scenery. As part of this effort, the Department of Botany of the Smithsonian Institution surveyed the marine algae.

In 2006 and 2007, The New York Botanical Garden participated in surveying the bryophytes, lichens, and vascular plants of the island. Although small in size, Saba's rugged topography is covered by several vegetation types, ranging from near desert to cloud forest. Our goal is to provide illustrated checklists (a virtual museum) of all of the plants and lichens that grow on Saba and in the surrounding sea. Both native and introduced plants are included.

To find collections representing species of flowering plants, gymnosperms, ferns, bryophytes, marine algae, or lichens, you can access the information available for a given group by clicking on the appropriate image on the left hand side of this page.

It is forbidden to pick plants and to remove plants from the island of Saba. All natural history studies must first be approved by the government of Saba. To find out how to obtain permission to collect herbarium specimens as was done in this study contact the Saba Conservation Foundation.

All photographs are copyrighted by the photographer. Most of the photographs of the flowering plants, gymnosperms, ferns, bryophytes, and lichens were taken by Carol Gracie and most of those of the marine algae were taken by Diane LittlerHarrie Sipman took the photo micrographs of the lichens. For permission to use the images, contact the photographers. Citizens of Saba have permission to download images from the website for personal or educational purposes.

Date
2007
Data type
Portal
Theme
Research and monitoring
Geographic location
Saba
Image
Plants and Lichens of Saba

Sustainability of Wild Plant Extraction on the Dutch Caribbean Island Sint Eustatius

 

  1. An often overlooked mechanism driving local extinction or scarcity of species is the selective  plant extraction by humans. Not much scientific attention has been paid to selective plant harvesting and the use of plants by inhabitants of the former Dutch Antilles. The aim of this study was to make a rapid sustainability assessment of wild plant harvesting on Sint Eustatius. A quantitative plot inventory was done to gather abundancy data on plants in the wild, and 31 interviews were conducted to collect information on local names, plant uses, preparation methods and harvesting locations. In total, 181 plant species belonging to 63 different plant families were mentioned as useful by the inhabitants of Sint Eustatius. Of these species, 66 were harvested exclusively from wild sources. Several wild species were cultivated in gardens. We found four wild-harvested species (Melocactus intortus, Nectandra coriacea, Pilosocereus royenii and Chiococca alba) that may encounter sustainability problems in the future, or might experience them already. From our study we can conclude that for the majority of useful species on Sint Eustatius, plant extraction does not form an immediate threat to their survival. 

 

Date
2016
Data type
Research report
Theme
Research and monitoring
Geographic location
St. Eustatius

Reef flattening effects on total richness and species responses in the Caribbean

1. There has been ongoing flattening of Caribbean coral reefs with the loss of habitat having severe implications for these systems. Complexity and its structural components are important to fish species richness and community composition, but little is known about its role for other taxa or species-specific responses. 2. This study reveals the importance of reef habitat complexity and structural components to different taxa of macrofauna, total species richness, and individual coral and fish species in the Caribbean. 3. Species presence and richness of different taxa were visually quantified in one hundred 25-m2 plots in three marine reserves in the Caribbean. Sampling was evenly distributed across five levels of visually estimated reef complexity, with five structural components also recorded: the number of corals, number of large corals, slope angle, maximum sponge and maximum octocoral height. Taking advantage of natural heterogeneity in structural complexity within a particular coral reef habitat (Orbicella reefs) and discrete environmental envelope, thus minimizing other sources of variability, the relative importance of reef complexity and structural components was quantified for different taxa and individual fish and coral species on Caribbean coral reefs using boosted regression trees (BRTs). 4. Boosted regression tree models performed very well when explaining variability in total (823%), coral (806%) and fish species richness (773%), for which the greatest declines in richness occurred below intermediate reef complexity levels. Complexity accounted for very little of the variability in octocorals, sponges, arthropods, annelids or anemones. BRTs revealed species-specific variability and importance for reef complexity and structural components. Coral and fish species occupancy generally declined at low complexity levels, with the exception of two coral species (Pseudodiploria strigosa and Porites divaricata) and four fish species (Halichoeres bivittatus, H. maculipinna, Malacoctenus triangulatus and Stegastes partitus) more common at lower reef complexity levels. A significant interaction between country and reef complexity revealed a non-additive decline in species richness in areas of low complexity and the reserve in Puerto Rico. 5. Flattening of Caribbean coral reefs will result in substantial species losses, with few winners. Individual structural components have considerable value to different species, and their loss may have profound impacts on population responses of coral and fish due to identity effects of key species, which underpin population richness and resilience and may affect essential ecosystem processes and services.

Date
2015
Data type
Scientific article
Theme
Research and monitoring
Geographic location
Bonaire
Image
Highly complex reef at Bonaire

The effectiveness of two bat species as pollinators of two species of columnar cacti on Curaçao

Two species of columnar cacti, Subpilocereus repandus and Stenocereus griseus, are pollinated on Curacao by two species of glossophagine bats, Leptonycteris curasoae and Glossophaga longirostris (Phyllostomidae). The pollination effectiveness of the two bat species can influence the evolution of this mutualism as well as the immediate availability of resources to frugivores and omnivores. I examined the effectiveness of single-visits by L, curasoae and G. longirostris on fruit-set, seed number, and fruit size for each cactus species. Single visits of L. curasoae produced higher fruit-set and seed number in Subpilocereus repandus than did single visits of G, longirostris, but the differences were not statistically significant, possibly as a result of the small size of the L, curasoae sample. The reverse trends were observed for Stenocereus griseus, Pollination of Subpilocereus repandus by L, curasoae resulted in significantly longer fruits than did pollination by G. longirostris, During the peak of the flowering season, flowers received many visits per night. Fruit size (length, width, total mass, pulp mass) was positively correlated with the number of seeds per fruit. These results indicate that the species of bats visiting cactus flowers, as well as the number of visits to flowers, may affect pollination success, and consequently may affect the carrying capacity of the environment in terms of fruit resources for animals that feed on cactus fruits.
 
The effectiveness of two bat species as pollinators of two species of columnar cacti on Curacao.
Available from: https://www.researchgate.net/publication/239042041_The_effectiveness_of_...
[accessed Apr 16, 2015]
 

Date
1998
Data type
Scientific article
Theme
Research and monitoring
Journal
Geographic location
Curacao
Author

Important Bird and Biodiversity Areas (IBA) map of Bonaire

Important Bird and Biodiversity Areas (IBA) map of Bonaire (GIS).

See Bird life international website for program description

Date
2013
Data type
Maps and Charts
Theme
Research and monitoring
Document
Geographic location
Bonaire

The cetaceans of Aruba, southern Caribbean

Abstract:

Aruba is one of the most densely populated islands in the Caribbean. However, very little is known about its cetaceans. In 2010 and 2011, a total of 19721 km (1686 h) boat-based surveys over nearshore transects resulted in 117 positively-identified sightings comprising eight species. New records are also added for one of three previously-documented species. Five additional species were documented from strandings or reports by others. This brings the total number of cetacean species identified in Aruban waters to 16, of which nine are authenticated here for the first time. Atlantic spotted dolphin (Stenella frontalis (N 1⁄4 59) and bottlenose dolphin (Tursiops truncatus) (N 1⁄4 33) were the most frequently observed species, with sightings of both year-round, followed by spinner dolphin (S. longirostris) and false killer whale (Pseudorca crassidens). Additional species recorded are pantropical spotted dolphin (S. attenuata), striped dolphin (S. coeruleoalba), common dolphin (Delphinus capensis), rough-toothed dolphin (Steno bredanensis), short-finned pilot whale (Globicephala macrorhynchus), killer whale (Orcinus orca), Risso’s dolphin (Grampus griseus), humpback whale (Megaptera novaeangliae), Bryde’s/Eden’s whale (Balaenoptera brydei/edeni), sperm whale (Physeter macrocephalus) and an unidentified beaked whale (Mesoplodon sp.). All cetaceans were sighted within 22 km of the coast in relatively shallow waters. Sighting rate was low (0.69 cetacean sightings per 100 km). Sightings of calves and neonates indicate that Aruba may be a nursing or breeding area for some species. The presence of several species of cetaceans in Aruba’s coastal waters year-round indicates that status and threat assessments are needed to protect them. 

Date
2013
Data type
Scientific article
Theme
Research and monitoring
Geographic location
Aruba

Biological Inventory of Saba

Abstract:

Saba is the smallest of the three Windward Islands in the Netherlands Antilles, with an area of 13 km2. Saba is the northernmost island within the Lesser Antilles' inner curve. The island is actually the top of a dormant volcano. Typical of the island are the steep cliffs, deep ravines running radially and sheer cliff coasts. The highest top is the Mt. Scenery, commonly called “The Mountain”. About 1200 people live on Saba in four villages all situated on the south- eastern half of the island. The northwestern half is not inhabited. Only a small part of the land area is used for agriculture or cattle breeding. In the south there is a stone crusher facility.

The climate is tropical and according to the system of Köppen it falls between a savanna- and monsoon climate, however the big differences in altitude cause a large variety of climatologi- cal conditions. Above 450 meters the rainfall and humidity gradually increase until they reach their maximum on the top of The Mountain. The top of The Mountain is nearly always veiled in clouds. The diversity of plants and plant-communities is caused by these variations in climatological conditions.

With 520 species the small island of Saba possesses practically the same number of species of wild plants as the much larger island of St. Maarten. The number of ferns is especially large. Saba has no island-endemic species among the plants. However, the geographical distribution of six species and one variety is limited to only a few islands, and 4.6% of the species is en- demic to the Lesser Antilles and the Virgin Islands. The Bryophyte flora consists of 48 leaf mosses and 31 liverwort species.

Expressing the differences in climatological conditions as the altitude increases, a series of plant communities are found, ranging from Croton thickets to (secondary) rainforest and elfin woodland. The elfin woodland is of a regionally rare type. The palm brakes and the ravine rainforest are practically undisturbed by human activities. They belong to the few virgin vegetations of the Netherlands Antilles. The tree-fern brakes are a special type of secondary vegetation, which develops under conditions of high humidity. The secondary rainforest zone was seriously disturbed in the past. There are still small cultivation plots here. Wherever the vegetation is left alone however, new rainforest is developing. The rainforest is one of the most species-rich plant communities. This is also where the greatest number of leaf mosses are found on Saba. The evergreen and seasonal formation zones were also disturbed in the past, however the vegetation is recovering. The great variety of forest formations on The Mountain makes this area highly attractive to visitors. The uninhabited area in the northwest of the island is important to the survival of various small island populations and has a high scenic value.

Saba's fauna has very few species compared to a similar area on the mainland, but this is to be expected from a relatively isolated small island.
Among the vertebrates the birds form the largest group, represented by 26 local and breeding species. In addition 36 migrating species are present every year on a temporary basis. Amphibians and reptiles are the next largest group of vertebrates with eleven species.

Bats are the only mammals on Saba that were not introduced by humans. This group is represented by five species. There is one island endemic among the vertebrates: the lizard Anolis sabanus. One species, the Red-bellied Racer Alsophis rufiventris is limited to Saba and St. Eustatius and is listed on the “Red List of Threatened Animals” of the IUCN. Various vertebrates are endemic to the Lesser Antilles and the Virgin Islands, either at the species level or the subspecies level: two bats, nine birds, one amphibian and one reptile. The gecko Sphaerodactylus sabanus, the bat sub-species Natalus stramineus stramineus and the Trembler Cinclocerthia ruficauda pavida have a geographical range, which is limited to only a few islands. Among the birds and reptiles there are species of which the population has declined because of hunting or the gathering of the eggs, like for instance the Rednecked Pigeon Columba squamosa, the Audubon's Shearwater Puffinus lherminieri, and the green Iguana Iguana iguana. A few bird species are regionally almost completely limited to the habitat of the rainforest and the mountain formations, e.g. the Purple-throated Carib Eulampis jugularis, the Trembler Cinclocerthia ruficauda pavida and the Blue-crowned Euphonia Euphonia musica flavifrons, which has not been seen since 1952. The possibly endangered Bridled Quail-dove Geotrygon mystacea and Red-billed Tropicbird Phaeton aetherius mesonauta breed on Saba. Of the latter the breeding population on Saba is the largest of the Caribbean region. Of the invertebrates not much more is known than 86 names. The Mountain Crab Gecarcinus ruricola is endangered through hunting.

In the past the nature of Saba was mainly impacted by activities related to agriculture and cattle breeding. Today, the most important threats are destruction and degradation of habitat by development in general, especially because of the lack of regulations.
Since the nineteenfifties there is a lot of interest in the conservation of nature and the beautiful scenery. The necessity to preserve the top of The Mountain is mentioned many times, accompanied by specific plans. A group of people even promoted the idea to declare the whole island of Saba a conservation park. Up until today however, the terrestrial nature on the island remains unprotected.

Several studies have produced a wealth of data, yet not enough for optimum nature conservation. Further vegetation research of the top of The Mountain and the northern part of the island is necessary, as well as further study of the status of the island populations of regionally rare and/or endangered species. Also additional knowledge of the invertebrates is needed.

For now a few general conclusions can be drawn with respect to conservation of the biodiversity. For this conservation it is necessary to secure large contiguous areas. For small islands this can be problematic, but there are still a lot of possibilities on Saba. In particular the uninhabited northwestern part of the island and The Mountain above 450 meters would qualify. Specific conservation is required for the breeding places of the Audubon's Shearwater, Tropicbirds and other seabirds on Green Island and Diamond Rock. 

Date
1997
Data type
Research report
Theme
Research and monitoring
Report number
KNAP project 96-10
Geographic location
Saba
Author