Aim Our aim was to investigate genetic structure in Neotropical populations of common green iguanas (Iguana iguana) and to compare that structure with past geological events and present barriers. Additionally, we compared levels of divergence between lineages within Iguana with those within closely related genera in the subfamily Iguaninae. Location Neotropics. Methods DNA sequence data were collected at four loci for up to 81 individuals from 35 localities in 21 countries. The four loci, one mitochondrial (ND4) and three nuclear (PAC, NT3, c-mos), were chosen for their differences in coalescent and mutation rates. Each locus was analysed separately to generate gene trees, and in combination in a species-level analysis. Results The pairwise divergence between Iguana delicatissima and I. iguana was much greater than that between sister species of Conolophus and Cyclura and non-sister species of Sauromalus, at both mitochondrial (mean 10.5% vs. 1.5–4%, respectively) and nuclear loci (mean 1% vs. 0–0.18%, respectively). Furthermore, divergences within I. iguana were equal to or greater than those for interspecific comparisons within the outgroup genera. Phylogenetic analyses yielded four strongly supported, geographically defined mitochondrial clades (3.8–5% divergence) within I. iguana. Three of the four clades were found using PAC (0.18–1.65% divergence) and two using NT3 (0.6% divergence) alone. The primary divergence, recovered in three polymorphic loci, was between individuals north and south of the Isthmus of Panama. The southern group was differentiated into clades comprising individuals on either side of the northern Andes, using both PAC and ND4. Main conclusions Deep genetic divergences were found within I. iguana that are congruent with past and current geological barriers. These divisions are greater than sister species comparisons in other Iguaninae genera, indicating the possible presence of cryptic species. Geological changes from the midMiocene through the Plio-Pleistocene have shaped the pattern of divergence in I. iguana. The uplift of the northern Andes presented a barrier between South American I. iguana populations by 4 Ma. Populations north of the Isthmus of Panama form a clade that is distinct from those to the south, and may have expanded northwards following the closing of the Isthmus of Panama 2.5 Ma
A review of the introduced agricultural pests and animal and plant diseases and vectors for the Dutch Caribbean in which a total of 47 exotic pests, diseases, parasites and pathogens established on one or more of the Dutch Caribbean islands are listed and discussed. These include 2 species of voracious herbivorous snails, 7 species of millipedes, 8 species of invasive ants, and some 16 species of insects that infest plants. Most agricultural pests are not strongly host-specific and will typically also affect native plants and/or animals. This makes it very difficult to eradicate or control these species once established. Therefore, prevention and early eradication is key.
The most information on invasive alien pests is available for the leeward Dutch islands while the least is known for the windward Dutch islands. The principal means of entry is the importation of unsterilized soil and plant material through container shipment, import of ornamental plants and air traffic. The economic costs, both in terms of damages and control measures, as well as missed opportunities that these species cause, has not been estimated but certainly runs in the millions of dollars annually. By far the most economically costly invasive species is the yellow fever mosquito Aedes aegypti, a pest and disease vector closely associated with man. In a few cases, biological control and eradication has been successful.
Introduction of invasive pest species continues at a high rate in the Dutch Caribbean and preventive measures are urgently needed to limit future costs and risks in terms of economy and health.
Key recommendations are: a) to strongly restrict and control importation of ornamental plants, most of which can be propagated locally without risk of new introductions, b) restrict importation of unsterilized foodstuffs, c) practice tighter control and prophylactic fumigation of container shipments, d) continue strict veterinary controls on animal importations. To effectively implement such measures, will require greater awareness, supporting legislation, cooperation of customs agents and shippers and the presence of a biosecurity unit authorized and equipped to act on short notice.
Based on experiences in other Caribbean countries and existing trade patterns and taking into account which species could survive in an arid climate, it is possible to draw up a preliminary listing of “Alert” species for the Dutch Caribbean. Such a listing is a critical tool for effective prevention. The preliminary Alert list discusses 21 species to be on the look-out for, most of which are insects and most of which can be expected to cause important damage to crops and/or nature, or both, if introduced.
The National Nature Policy Plan 2001-2005 (NPP-5) and its current status of implementation was assessed as a first step towards a new Nature Policy Plan for the Caribbean Netherlands (Bonaire, Saba, St. Eustatius). The purpose of this exercise is to determine which action points of NPP-5 are still relevant, and to identify key new developments to be aware of when setting goals and strategies for the new Nature Policy Plan for the Caribbean Netherlands. The NPP-5 was the first formal nature policy plan of the Netherlands Antilles. It lists a total of 47 policy goals and projects in the text for the period 2001-2005. Based on these, 61 action points were listed in an Action Matrix for the period 2001-2005. Of these 31 were achieved to a high degree of completion between 2001 and 2010, notwithstanding the serious and chronic lack of both funds and manpower (NEPP-7). Based on this assessment, a total of 40 action points may be brought forward based on the NPP-5. These not only include most “one-time” action points not yet achieved but also several action points that were achieved but which are of an on-going nature.
While much has been achieved in terms of policy development and legal frameworks over the last 10 years, climate change implies that future nature management will be confronted with an increasingly rapid succession of major ecological problems such as coral bleaching, hurricane impacts, and invading species.
Our quick-scan assessment showed that policy development over the last 10 years has suffered significantly from challenges in terms of both capacity and funding, as well as in decision-making in reaching its goals. Controversial topics regarding “rules and regulations”, “cooperation”, and “financial instruments” largely failed to be achieved due to problems in the decision making process, whereas less controversial action points such as “reporting”, drawing up “plans”, doing “research” and “education”, especially suffered from a lack of capacity and funding.
Several main topics are identified that will need attention in the new nature management plan. The new nature policy will have to meet standard and basic policy needs, information and management needs, and also have to accommodate the latest conceptual developments and the pressing realities of global climate change and alien species invasions. Notable is that a large number of new and serious threats have come to the forefront since the NPP-5 was set 10 years ago.
Because the diverse, colourful and unique natural ecosystems of the Caribbean Netherlands also represent the single most important local economic resource on which to build long-term prosperity of the inhabitants of these islands, the nature policy plan needs to be recognized as much more than simply a way to protect nature and avert ecological crisis. It is in fact a key policy tool by which to actively safeguard and create economic well-being and opportunity for these islands.
A crossword puzzle for children about bats
In augustus 2011 is er op Bonaire onderzoek gedaan naar de manier waarop de exploitatie van een rioolstelsel en een rioolwaterzuiveringsinstallatie op een verantwoorde manier kan plaatsvinden. Dit onderzoek is door de Stichting ABC Advies uitgevoerd op verzoek van USONA, die ter plaatse dit project begeleidt en de financiering ervan bewaakt namens de EU. Het onderzoek is uitgevoerd door lezing van een groot aantal publicaties van verschillende aard. Voor zover deze van belang zijn, zijn deze genoemd in dit rapport. Naast lezing van documenten is het bezoek ter plaatse en de diverse gesprekken met direct verantwoordelijken zoals bestuurders, medewerkers van USONA en anderen betrokkenen van grote waarde voor de beeldvorming van de onderzoeker geweest. In de bijlagen bij dit rapport is een lijst van gevoerde gesprekken opgenomen1 . De kern van de onderzoeksuitkomst is dat het hebben van een rioolstelsel en een zuivering voor Bonaire van onschatbare waarde is, maar dat door het Openbaar Lichaam Bonaire nog veel keuzes moeten worden gemaakt alvorens een heffingenstelsel operationeel is. In het rapport worden daarvoor enkele richtinggevende mogelijkheden geschetst. De bijkomende problematiek van een tijdelijke afvalwaterzuivering die een nogal permanent karakter heeft gekregen is complicerend, ook voor de dekking van de exploitatielasten, maar maakt geen onderdeel uit van de onderzoeksvraag. Dit geldt eveneens voor het vraagstuk van het beheer van de zuivering. Ook dat onderwerp, hoewel het zeker raakvlakken heeft met de exploitatiekosten en dus ook het tarief, kan –vanwege de onzekerheid over de uitkomst van dit vraagstuk- geen onderdeel uitmaken van dit rapport. Bij dit rapport is een opzet gemaakt voor een kostenoverzicht van de jaarlijkse exploitatielasten van het ‘Bonaire Sewerage and Sanitation Project’. De onderzoeksperiode van ruim 1 week is niet voldoende om deze cijfers ook zonder nader onderzoek en overleg met (technisch en financieel) ter plaatse deskundigen over te nemen. De opzet biedt naar de mening van onderzoeker wel een aanzienlijk beter inzicht dan tot nu voorhanden was. Vanaf het moment dat het Bestuurscollege en de Eilandraad enkele, in deze rapportage genoemde, keuzes hebben gemaakt is het (nog) verder uitwerken van de exploitatiebegroting en het tarievenstelsel aan de orde. Ook kan dan de benodigde regelgeving worden opgesteld. Het zou, vanwege het grote belang dat met het slagen van dit project is gemoeid, naar de mening van onderzoeker een goede vervolgstap zijn dat de uitkomsten van deze rapportage met direct betrokkenen op het Bonaire worden besproken. Daarbij wordt gedacht aan de DROB, het hoofd financiën en andere betrokkenen. Indien nodig kan dan verfijning plaatsvinden.
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.
A semi-detailed landscape-based vegetation map (scale: 1: 37,500) based on field data from 1999 has been available as an update of Stoffers’ 1956 map of the Lesser Antillean island of St. Eustatius, Netherlands Caribbean, but up to now was never finalized or published. In this report we complete the documentation of that map to provide new insights into vegetation change over a period of more than 40 years, and a quantitative reference point for future studies on landscape-level vegetation development for the island.
The principal lower sections of the 21 km2 island of St. Eustatius possess a tropical savannah climate according to the Köppen (1931) classification system, and the documented flora of the island amounts to 505 species. Color aerial photographs (1: 8,000) taken in 1991 and field data from 1999 were used to produce the map. A total of 84 vegetation sample plots were analysed using a stratified random sampling design and TWINSPAN cluster analysis.
Four main and 16 sub-landscape types were distinguished based on geology, geomorphology and different mixes and expressions of the component vegetation types. The five principal landscape types are in descending order of importance: H1, H2, M4, M9 and C, and covered some 67 % of the seminatural habitat of the island. H1 and H2 are the Pisonia-Justicia hills and Pisonia-Bothriochloa hills and are limited to The Mountains area. Analysis of the sampling data resulted in the distinction of 13 (semi)natural vegetation types. The three principal vegetation types were, the Pisonia-Justicia type, Pisonia-Ayenia type and Bothriochloa-Bouteloua type which together accounted for 38 % of total (semi)natural vegetation cover. The following well-developed vegetation types of St. Eustatius represent primary climax communities: Types 1, 2, 3, 5 and 7, all found in and around the Quill in the southwestern part of the island. A comparison of the vegetation types in the present study with those of Stoffers (1956) showed that only one vegetation type closely resembles one in Stoffers’ study. Major changes have taken place in certain types of the natural vegetation of the island in the intervening five decades.
The majority of the central sections of the island around Oranjestad the so-named “Cultuurvlakte”, amounting to approximately 25 % of the surface of the island, have suffered intensive disturbance due to past agriculture, livestock husbandry and invasive species and were not mapped. Only a small remnant portion of the semi-natural lowlands vegetation (L1 and L2) was left in the coastal reaches of Billy’s Gut. Nevertheless, this area is heavily affected by grazing and the invasive vine Antigonon leptopus.
A comparison with the 1950s vegetation map by Stoffers shows that the rarest and most valuable elfin woodland vegetation of the rim of the Quill crater had been largely lost and that the areas he described as “Montane thickets” (Type 2) had declined and been degraded. We speculate that these losses may be most directly attributable to the impact of recent hurricanes and/or grazing by introduced livestock. On the lower slopes of the Quill, several areas mapped by Stoffers as farmland had been abandoned and have evidently regenerated into mixed deciduous and evergreen thorny woodlands.
The vegetation of the Mountains area showed some recovery since the 1950s. There were more evergreen bushes, and less Acacia and Leucaena than Stoffers described. The vegetation Stoffers described for the lowlands had more Acacia than we found but the invasive Antigonon has since dramatically increased as a ubiquitous and often dominant species. The former importance of Opuntia prickly pear cacti in disturbed vegetations has dramatically declined since the 1950s. We ascribe this to the likely effect of the invasive parasitic insect Cactoblastis cactorum. In the 1980s and 1990s many Opuntia cacti were seen affected by this insect (G. Lopes, pers. comm.).
Our field data show that all wilderness areas of St. Eustatius remained heavily affected by grazers. This reduces the resilience of natural vegetations and interferes with natural succession by imparting heavy losses to hardwood seedlings and saplings (see e.g. Melendez-Ackerman et al. 2008), by reducing plant biomass (which increases exposure to wind and sun), and by favoring hardy invasive plant species. In Curaçao, large scale reduction in densities of feral grazers in the Christoffelpark since 1993 has led to rapid recovery of several rare plant species and vegetation types. The problem of feral livestock remains severe. Therefore the number one priority for terrestrial conservation in St. Eustatius will be to reduce feral grazer densities and impacts in key wilderness areas.
Parts of the natural areas of both The Mountains and the Quill are protected by law, but goats and other roaming livestock are omnipresent in all habitats and continue to have evident impacts on the vegetation. Aside from generally reducing the resilience of the vegetation to major disturbance, intensive impact in the herbaceous layers likely affects regeneration of rare hardwood species directly through selective predation and indirectly by overall desiccation and increased exposure to the elements. Goats have a broad diet in the region and species eaten include canopy, mid-canopy and understory species (Melendez-Ackerman et al. 2008). Vegetation degradation further also affects the competitive balance towards (unpalatable) invasive species such as Antigonon leptopus, Pedilanthus tithymaloides, and Leucaena leucocephala, which have expanded massively into natural habitat in the last 50 years. Not only is general vegetation degradation suggested as a problem to endangered breeding seabirds, but goats likely also directly trample nesting burrows of seabirds (Collier & Brown 2009).
Consequently, priorities for nature conservation are to:
- Reduce grazer densities in all areas,
- Protect the most sensitive vegetations using total grazer exclusion, and
- Experiment with methods to spur vegetation recovery, including erosion control, propagation of rare and endangered species and reforestation with indigenous species
- Establish permanent plots in areas with the most sensitive vegetations in order to better understand causal factors of short- and longer term changes.
This report is part of the Wageningen University BO research program (BO-11-011.05-004) and has been financed by the Ministry of Economic Affairs, Agriculture and Innovation (EL&I) under project number 4308202004.