Biological Conservation

Seagrass beds and mangroves as potential nurseries for the threatened Indo-Pacific humphead wrasse, Cheilinus undulatus and Caribbean rainbow parrotfish, Scarus guacamaia

The importance of seagrass beds and mangroves as a juvenile habitat as opposed to other shallow water habitat types is investigated using a single sampling method on four islands in the western Indian Ocean for Cheilinus undulatus, and on one island in the southern Caribbean Sea (Aruba) for Scarus guacamaia. Both species occur on the Red list of threatened species. Juveniles of Cheilinus undulatus were predominantly found on seagrass beds while adults were limited to the coral reef. The presence of seagrass beds resulted in significantly higher densities of the species on coral reefs in front of these habitats, indicating the importance of seagrass beds as a juvenile habitat. For Scarus guacamaia, juveniles were exclusively observed in mangroves while adults only occurred on the coral reef. Adult S. guacamaia occurred on all coral reefs along the sheltered coast of the island containing mangroves, but no relationship with distance to mangroves was observed. This could indicate the importance of mangroves for the occurrence of adults of this species on the scale of an entire island.

Date
2005
Data type
Scientific article
Theme
Research and monitoring
Geographic location
Aruba
Private Document

Effects of feral goats (Cupru hircus) on island ecosystems

Feral goats (Capra hircus) are implicated in habitat destruction, and alteration of species composition on sensitive insular ecosystems. In the absence of population control, goats have become the ecologically dominant species on many islands with the results that numerous endemic plant species have been extirpated, or are threatened by excessive grazing. It is demonstrated that removal of goats can lead to rapid recovery of suppressed vegetation. The problems associated with excessive numbers of feral goats have rarely been studied or formally recognised. Extensive and intensive research is critically needed if affected island ecosystem are to be preserved or restored.

 

Date
1978
Data type
Scientific article
Theme
Research and monitoring

The status of bats on Curaçao

The bat population of the island of Curaçao, Netherlands Antilles, was surveyed in 1992 and 1993. The 1993 survey concentrated mostly on caves, which were found to host most of the bats. Glossophaga longirostris elongata was the most abundant species with fewer than 2000 individuals encountered. However, this species may also be found in small groups in buildings and caves that were not censused. More critical is the status of the other six species found on the island: Leptonycteris curasoae (800–1000), Mormoops megalophylla intermedia (570–650), Natalus tumidirostris (50–60), and three species for which the number of individuals is unknown and probably low: Myotis nesopolus, Pteronotus davyi and Noctilio leporinus. Three caves contain all of the above species, except N. leporinus, and should be actively protected. Two species expected to be present on Curaçao, Artibeus jamaicensis and Molossus pygmaeus, were not found. The apparent decrease in bat numbers this century is likely a result of uncontrolled cave disturbance and removal of resources through development. I propose that all species be considered endangered on the island of Curaçao, except for Glossophaga longirostris, which is threatened.

Date
1996
Data type
Scientific article
Theme
Research and monitoring
Tags
Geographic location
Curacao
Author