Central repository for biodiversity related research and monitoring data from the Dutch Caribbean
A crossword puzzle for children about bats
Over the past decade, Indo-Pacific lionfishes, Pterois volitans (Linnaeus, 1758) and Pterois miles (Bennett, 1828), venomous members of the scorpionfish family (Scorpaenidae), have invaded and spread throughout much of the tropical and subtropical northwestern Atlantic Ocean and Caribbean Sea. These species are generalist predators of fishes and invertebrates with the potential to disrupt the ecology of the invaded range. Lionfishes have been present in low numbers along the east coast of Florida since the 1980s, but were not reported in the Florida Keys until 2009. We document the appearance and rapid spread of lionfishes in the Florida Keys using multiple long-term data sets that include both pre- and post-invasion sampling. Our results are the first to quantify the invasion of lionfishes in a new area using multiple independent, ongoing monitoring data sets, two of which have explicit estimates of sampling effort. Between 2009 and 2011, lionfish frequency of occurrence, abundance, and biomass increased rapidly, increasing three- to six-fold between 2010 and 2011 alone. In addition, individuals were detected on a variety of reef and non-reef habitats throughout the Florida Keys. Because lionfish occurrence, abundance, and impacts are expected to continue to increase throughout the region, monitoring programs like those used in this study will be essential to document ecosystem changes that may result from this invasion.
In the present note, we revise the scorpion fauna of the small island of Sint Eustatius, in the Lesser Antilles. A total of two families, three genera and three species are confirmed to occur there: the buthids Centruroides barbudensis (Pocock, 1898) and Isometrus maculatus (DeGeer, 1778), and the scorpionid Oiclus purvesii (Becker, 1880). These include the first record of the occurrence in Sint Eustatius of the family Scorpionidae and the genus Oiclus Simon, 1880, as well as the first published findings of I. maculatus since 1942. A key to the easy identification of all three species is provided.
Management Recommendations:
Lac Bay, Bonaire is the most important mangrove and seagrass area of Bonaire and has been undergoing steady ecological decline in the last decades. Based on an initial assessment of conservation management issue and potential solutions, as, conducted by IMARES in June 2010, the Dutch Ministry of Agriculture, Nature and Food Quality (LNV) asked IMARES to return to Bonaire to work with Stinapa Bonaire to choose narrower priorities and jointly make a short-list of topics as a working document for cooperation and action. In the beginning of September, site visits and discussions were held in Bonaire with the manager of Lac Bay and various stakeholders to identify and agree on priority issues for action. This working report gives the results of that visit.
Four action spear point projects were identified, based on urgency and feasibility based on local Bonaire and Dutch IMARES expertise. The projects are as follows:
1. Mangrove restoration demonstration pilot study
The basic objective is to reestablish water depth and tidal connection in high marsh salt areas that have resulted from infilling with sediment, and restore them as effective mangrove and low marsh fish nursery habitats. By collecting baseline data before the restoration activities take place, it will be possible to monitor and compare and assess changes in fauna and flora at the restoration sites and hence evaluate the effectiveness of the measures implemented.
2. Baseline ecological study of the zonation of aquatic communities
The goal is to complete a scientific description of Lac’s aquatic community zonation as it exists at landscape level today. This will provide the framework against which large-scale community change and effectiveness of mitigation measures can be monitored and evaluated.
3. Recreational and land use survey for Lac Bay and its catchment area
The goal is to identify user problems and potential solutions by mapping and assessing user density and pressures in Lac
4. Study of avifaunal habitat use of Lac Bay
The goal is to identify bird habitat use problems and potential solutions by assessing habitat use of Lac by birds during the migratory season.
(A fifth project for implementation by Stinapa and Dienst LVV was identified)
5. Lac mangrove channel clearing project
Re-establish water flow from the Bakuna dam to Lac using a pipe system.
The Lac mangrove channel clearing project of Stinapa was reviewed and judged to be valuable and important. The baseline study of zonation of aquatic communities (project 2) is urgently needed in this respect to allow short and long-term evaluation of this project which need to become a structural part of Lac Bay management. Routine mangrove channel maintenance was identified as ideal work for involvement of Bonaire youths and volunteers, to rekindle public involvement in caring for Lac and its rich natural and cultural-historical heritage.
Management Recommendations:
A project plan is presented by which all four projects can be delivered by December 2012. These projects can count on government and broad community support. In this all, Stinapa indicated to be willing to provide basic free lodging to interns and scientists at their science accommodations at the entrance of Washington-Slagbaai National Park. The ability and willingness of IMARES to recruit and guide students and interns for these projects was an important selection criterion to help restrain total project costs. The action spear points will, nevertheless, require funding as well as permits from the Island Government of Bonaire. With LNV various funding options were reviewed and discussed, and the need for permits was discussed with DROB (Dienst Ruimtelijke Ontwikkeling en Beheer) Bonaire. DROB envisioned few problems with the required permits. The visit was concluded by the joint resolve to work out ways to maintain momentum and proceed towards the implementation phase.
Management Recommendations:
Abstract:
The endangered Lesser Antillean Iguana, Iguana delicatissima, is an emblematic species for the island of St. Eustatius and in Caribbean Netherlands it is only found on St. Eustatius. In this study we conducted an extensive population survey for the iguana and compared densities in different areas to densities documented most recently in 2004. We conducted 39 field surveys and spent a total of 80 hours and 21 minutes searching for iguanas. We covered 63,672 m of trails and tracks and found only 22 iguanas. An overall average of 3.70 hours were searched for each iguana found. Due to the low encounter rates, detailed estimation and comparison of population densities remain problematic. Overall population density was 0.35 iguanas per hectare which represents 0.5-1% of densities documented elsewhere in healthy populations. Current population densities have declined across all habitats since the 2004 survey. Iguana encounter rates and densities in natural habitat were highest for the region where the northern hills abut onto the central plain. Island-wide, those areas provide the best combination of sun, shelter, food and potential for nesting sites. The population of the Lower Town sector, indicated in 2004 as the most dense and promising subpopulation, has all but disappeared. Island-wide, the residential estate subdivisions remains the second-most important area for the iguana.
We conclude that even though several valuable conservation measures are in place (e.g. establishment of legally protected parks, designation as a legally protected species and a successfully-run awareness campaign), the status of the iguana has not improved significantly in the last 8 years. Our results show that compared to 2004 when the population was estimated to number 425 (275-650) animals, current population size certainly lies on the low side of this range. This is far below the required minimum viable population size of 5000 animals and means that the iguana is critically endangered on St. Eustatius. It is readily vulnerable to extirpation on the island. Human hunting is likely a minor problem, shelter and food availability on the island are abundant, and invasive predator densities in the wild are relatively low. Of the 28 documented instances of death or endangerment of iguanas during the study period, most were attributable to anthropogenic causes. Suitable nesting sites for the iguana appear very limited, especially due to a combination of geology and vegetation. Therefore, lack of nesting sites and high iguana mortalities due to anthropogenic causes are suggested as the two core factors limiting recovery of the iguana on St. Eustatius .
Management Recommendations:
The following management measures are proposed:
1. Protect current populations by:
2. Increase the biological knowledge about the iguana by conducting studies for a better knowledge of the critical biological parameters,
3. Create public awareness for the plight of the species,
4. Establish a small, local husbandry project.
(Development of an in situ husbandry and breeding project could serve a pivotal role in bolstering the other core program themes and especially offers a relaxed setting in which islanders can experience the iguana as the gentle and beautiful animal that it is).
This report is part of the Wageningen University BO research program (BO-11-011.05-004) and was financed by the Ministry of Economic Affairs, Agriculture and Innovation (EL&I) under project number 4308701004.
