Identification of invasion status using a habitat invasibility assessment model: the case of Prosopis species in the dry zone of Myanmar.
In arid regions, land restoration projects that use alien plants often cause damage to ecosystems and the livelihoods of local people. Management of these invasive alien species is difficult without knowledge of the habitat invasibility of the regions where it has been introduced and the species' invasion status (absent, invading, or saturated). We developed a habitat invasibility assessment model that integrates the local plant community and mesoscale environments by controlling the effect of propagule pressure, to determine the habitat risk posed by Prosopis (mesquite) species introduced for land rehabilitation in the central dry zone of Myanmar (Burma). Current invasion status was assessed based on a vegetation survey and the invasibility assessment model. Habitats with dry and hot climatic conditions were suitable for Prosopis invasion. Tree patches in human-dominated landscapes showed higher invasibility to Prosopis than remnant forests. Large-scale geographic range expansion (≥10-km radii) had already been completed. However, at a smaller scale there were some sites lacking Prosopis and sites with a propagule deficit close to heavily invaded areas in suitable habitats, indicating that local invasion was in progress. These results suggest that ecological and economic damage caused by Prosopis will continue to increase unless propagule control measures are initiated.