GIS Unit - Montserrat vegetation mapping

Using predictive modelling and GIS technologies our work is helping the people of Montserrat to conserve the Centre Hills.

Vegetation map of the island of Monserrat A. Mansat

The West Indian island of Montserrat is one of the UK’s Overseas Territories (UKOTs). It is part of the Caribbean biodiversity hotspot recognised for the large number of endemic plants and animals that live nowhere else in the world. Like other mountainous islands within the biodiversity hotspot, Montserrat supports many different habitat types, due to the wide variation of soils, temperature and rainfall.

The volcanic eruptions of 1995-97 destroyed almost all the forests of the southern hill ranges, resulting in a loss of approximately 32% of Montserrat’s native forest ecosystem. The Centre Hills of Monserrat now hold the largest remaining intact area of forest. Vegetation and red-listing of threatened species is needed to set up a durable conservation program with all partners and local population.

Novel techniques based on ecological niche theory, utilize Maxent (maximum entropy) modeling technique, combined with expert knowledge and GIS analysis to allow both vegetation and species distributions to be predicted.

Collection points noting vegetation type and species presence were derived from extensive fieldwork. This data, combined with environmental (i.e. proximity to rivers) and topographic (i.e. Digital Elevation Model, DEM) data formed the base inputs for the modeling procedure. Decision rules processes were preformed using ArcMaps model builder tool to enable the overlays of presence probabilities of each vegetation types.

The modeled vegetation types were combined to form a map of the island’s vegetation before the eruption. The lava flows were then mapped and overlaid on to the vegetation map to show which types (of vegetation) had suffered the most as a result of the eruption. Two species of important endemic plants (Epidendrum montserratense and Rondeletia buxifolia) were also modeled using the same techniques.

The outputs derived from these GIS techniques, including the vegetation map, predicted distributions of two important endemic species and new environmental base data including a Digital Elevation Model (DEM) are accessible to conservation planners and the public to aid future fieldwork and conservation activities on the island. The map also aims to explain methods used by researchers and fieldworkers to set up conservation program in a comprehensive way.
The GIS techniques used have enabled us to produce a link between fieldwork, habitat model and species distribution. The accuracy of the outputs has been verified with subsequent fieldwork and targeted collections (to areas of the highest prediction).

All of this is combined in cartographic products and statistics which deliver the important information concisely to planners, decision makers and the general public. GIS software (ESRI suite) has been used for spatial analysis, data basing, 3D work and representation.

- A. Mansat, 2010 -