Distribution patterns of endemic flora to define hotspots on Hispaniola

Abstract

Nineteen areas on the island of Hispaniola (Haiti and the Dominican Republic) were studied with the aim of determining the distribution pattern of the endemic flora in these areas, and their variability with altitude. The main concentration of endemic species occurs in mountains with a medium altitude and in certain mountain sites (palaeo-islands), which coincide with hotspots; a lower number of endemics are found in low-lying areas (coldspots), due to the degradation of their habitats. A total of 1,582 endemic species were studied and were distributed in 19 areas. The whole island is of outstanding interest for its richness in endemics; it has 2,050 endemic species, representing 34.16% of its total flora. The territory in the study is home to 1,284 genera of which 31 are endemic to the island, including monotypical genera such as Tortuella abietifolia Urb. & Ekman, and endemic genera such as Hottea, containing seven endemic species. The sites with the highest rate of endemics are area A16 in the central range with a total of 440 endemic species, of which 278 are exclusive to the territory; and the Sierra de Bahoruco, la Selle, La Hotte and Tibur on in area A12, where we found 699 plants of which 482 are endemic and exclusive to the area; and A13 with 173 and 129 respectively. This work highlights the exceptional floristic diversity in endemic species and genera and analyses their distribution patterns as a tool for conservation in this area of the world, whose high endemicity rate makes it one of the most significant hotspots in the Caribbean.

Introductory Chapter: Endemism as a Basic Element for the Conservation of Species and Habitats

“…The results are various works on vegetation that describes a number of plant associations [1][2][3][4][5][6][7][8][9], all of great interest due to their endemic character. Other results include works on endemism [10] and a series of studies on the flora of the island published in the journal Moscosoa, together with the Flora of Hispaniola by [11]. This present research is a continuation of the aforementioned works, and we corroborate the bioclimatic and biogeographical studies [1,7,12,13].…”

“…Large mountain chains were formed in the Cretaceous era that was subsequently linked by Tertiary and Quaternary sediments. The Cordillera Central range is siliceous in character and has the highest altitude in the whole of the Caribbean region (Pico Duarte: 3175 m); other mountain chains also originated during the Cretaceous era but have a lower altitude and a calcareous character, with patches of serpentines, which contain a high rate of serpenticolous edaphisms [5,10]. Examples of this are the islands of Cuba and Hispaniola, which despite their limited territorial extension each have over 6000 plant species of which over 33% are endemic.…”

The new Hispaniolan genus Tainus (Rubiaceae) constitutes an isolated lineage in the Caribbean biodiversity hotspot

“…The recent findings stress the need to explore, collect and carry out phylogenetic studies to increase the floristic knowledge of Hispaniola and the Antilles. Within Hispaniola, a site of particular interest is the Sierra de Bahoruco-La Selle, for which the genus Hottea is endemic in addition to Tainus, underscoring its importance as an area of high diversity in Hispaniola, as stated by Cano-Ortiz & al. (2016), and definitely highlighting the need to protect this area of Hispaniola.…”

“…According to Cano-Ortiz & al. (2016), Hispaniola has 19 areas of particular high diversity, which are explained by altitudinal gradients and specific soil types.…”

“…2010). The Sierra de Bahoruco-La Selle stands out by being the most diverse mountain system within Hispaniola with several different ecosystem types and c. 700 species of vascular plants, of which about two thirds are endemic (Cano-Ortiz & al. 2016).…”