Pseudophoenix ekmanii is a threatened palm species endemic to the Dominican Republic. Sap from trees is extracted to make a local drink; once they are tapped the individual usually dies. Plants are also illegally harvested for the nursery trade and destroyed by poachers hunting the endemic and threatened Hispaniolan parrot. We used 7 DNA microsatellite markers to assist land managers in developing conservation strategies for this palm. We sampled 4 populations along the known distribution range of this species (3 populations from the mainland and 1 from the small island of Isla Beata), for a total sample of n = 104. We found strong evidence for genetic drift, inbreeding, and moderate gene flow (i.e., all populations had at least 4 loci that were not in Hardy-Weinberg equilibrium, at least 9 loci pairs were in linkage disequilibrium, the pairwise F(ST) values ranged from 0.069 to 0.266, and had positive F(IS) values). Data supported an isolation-by-distance model, and cluster analyses based on genetic distances resolved 2 groups that match a north-south split. The population from Isla Beata had the lowest levels of genetic diversity and was the only one in which we found pairs of individuals with identical shared multilocus genotypes.

del Soco and Laguna de Oviedo. With the plant samples taken in the above mentioned sites, we created a synthetic table out of 16 phytosociological tables belonging to 6 original associations and 9 associations obtained from the bibliographical study. With the purpose of obtaining a similarity gradient (matching) between the associations under study, we carried out a statistical analysis (clustering, principal component analysis and Jaccard similarity/dissimilarity analysis). Our phytosociological approach relied on criteria such as biogreography and dynamic-catenal contact. Our sampling analysis has led us to propose the following syntaxa: Machaerio lunati-Rhizophoretum manglis; Rhabdadenio biflorae-Laguncularietum racemosae; Sthalio monospermae-Laguncularietum racemosae; Lonchocarpo pycnifolii-Conocarpetum erecatae; Lonchocarpo sericeiLaguncularietum racemosae; Crataevo tapiae-Conocarpetum erectae. We also propose a new alliance and a change of status: Phyllantho elsiae-Laguncurion racemosae; Dalbergio-Rhizophorion manglis (Borhidi 1991) status novo. The mangrove swamps of Central America are arranged in three vegetation bands corresponding to different plant associations. The analysis of the three sampled area not only revealed the degradation of the vegetation but also the causative factors.

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We conduct a study of the dry forest in areas of scant rainfall in the Dominican Republic; these are sites with particular endemic habitats, as the samples reveal a high rate of local and insular endemic species, with 84 (24.85%) endemisms. This work covers dry forests rich in coarse spiny plants and includes a statistical (multivariate analysis), phytosociological and catenal study of the vegetation. We analyse the floristic composition, ecology, distribution and richness in endemisms of each association. The bioclimatic analysis reveals the different thermotypes and ombrotypes on the island, and locates the proposed plant associations in the infra-and thermotropical thermotypes, and in the arid, semiarid and dry ombrotypes. As a result of this phytosociological analysis, we propose the new alliance Harrio nashii -Acacion skleroxylae and four plant associations: Harrisio nashii -Prosopidetum juliflorae, Crotono poitaei -Erythroxyletum rotundifolii, Lonchocarpo pycnophylliCylindropuntietum caribaeae and Neoabbottio paniculatae -Guaiacetum officinali; these associations connect catenally with the subhumid forest and mangrove swamps.

Phylogenetic analyses of nucleotide sequences of the internal transcribed spacers and 5.8 regions of the nuclear ribosomal DNA and of the trnH-psbA spacer of the chloroplast genome confirm that the three taxa of the Jacquemontia ovalifolia (Choicy) Hallier f. complex (Convolvulaceae) form a monophyletic group. Levels of nucleotide divergence and morphological differentiation among these taxa support the view that each should be recognized as distinct species. These three species display unique intercontinental disjunction, with one species endemic to Hawaii (Jacquemontia sandwicensis A. Gray.), another restricted to eastern Mexico and the Antilles [Jacquemontia obcordata (Millspaugh) House], and the third confined to East and West Africa (J. ovalifolia). The Caribbean and Hawaiian species are sister taxa and are another example of a biogeographical link between the Caribbean Basin and Polynesia. We provide a brief conservation review of the three taxa based on our collective field work and investigations; it is apparent that J. obcordata is highly threatened and declining in the Caribbean.

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This paper is a floristic and phytosociological study of the dry forest communities of the Dominican Republic. A total of 69 relevés in dry forest biotopes were carried out. The samples were subsequently subjected to Detrended Correspondence Analysis for the determination and study of possible groupings. The study does not cover tree formations growing on serpentines, nor the so-called semideciduous forests, peculiar to areas with higher rainfall. A total of nine phytocoenoses were identified. The most significant results led to the description of six new phytosociological associations: Simaroubetum berteroani (thorny dry forest on coastal dunes), Phyllostylo rhamnoidis-Prosopidetum juliflorae (southern Dominican disturbed dry forest), Consoleo moniliformis-Camerarietum linearifoliae (dry forest on hard limestones), Lemaireocereo hystricis-Prosopidetum juliflorae (northern Dominican disturbed dry forest), Lycio americani-Prosopidetum juliflorae (disturbed dry forest on saline soils) and Guettardo ellipticaeGuapiretum discoloris (dry forest on flat-topped hillocks in Montecristi). This is an important step forward in the phytosociological and floristic studies of the Caribbean territories.