Land Suitability Mapping of the Most Illegally Harvested Plant Species using a GIS-based Model in Uganda

Abstract

Illegal harvesting of high-value plant species threatens biodiversity conservation and sustainable livelihoods in Uganda, particularly within and around Rwenzori Mountains National Park. This study applied a GIS-based land suitability modelling approach to identify potential areas for ex-situ conservation of selected illegally exploited species, including Warburgia ugandensis, Prunus africana, Maesa lanceolata, Albizia coriaria, Arundinaria alpina, and Albizia gummifera. A Multi-Criteria Evaluation (MCE) framework integrated climatic variables, soil properties, topographic factors, and land-use/land-cover data. The Analytic Hierarchy Process (AHP) was used to assign weights, while weighted overlay analysis in ArcGIS 10.8 generated species-specific suitability maps. Results revealed clear spatial variation in habitat suitability across Uganda, with highly suitable areas concentrated mainly in the western and south-western highlands of the Albertine Rift. Montane species such as Prunus africana and Arundinaria alpina exhibited restricted suitability ranges associated with cooler and wetter highland environments, whereas ecologically adaptable species such as Albizia coriaria and Albizia gummifera showed broader distribution patterns across multiple regions. Moderately suitable zones extended into parts of central Uganda, while northern and north-eastern regions were largely unsuitable due to higher temperatures, lower rainfall, and extensive land-use modification. The study demonstrates that GIS-based land suitability mapping is an effective decision-support tool for conservation planning. Identifying suitable habitats outside protected areas provides opportunities for ex-situ conservation, ecological restoration, and community-based cultivation. The findings offer spatially explicit guidance for policymakers and conservation agencies seeking to reduce pressure on in-situ populations while promoting sustainable management of valuable plant resources in Uganda