Roystonea princeps

Most of the individuals of this species occur within the Negril or Black River Morass regions of western Jamaica; other localities where this species have been recorded typically only contain a few isolated individuals and are therefore assumed to comprise a negligible proportion of the total global population. The Black River Morass covers an area of approximately 57 km² while the smaller Negril Morass covers an area of approximately 20 km². Within these areas, Roystonea princeps is restricted to the highly threatened swamp forest habitat, within which it is locally abundant and a dominant canopy-forming pioneer species. This habitat formerly covered large areas of the morass regions, but is now restricted to small, isolated, and severely threatened fragments. Swamp forest has experienced serious declines; 80% of this habitat has been estimated to have been lost in the larger Black River Morass over the past 80 years (Ramsar 2021). Loss of swamp forest has not been quantified in the smaller Negril morass but given the similarity in land-use history, the rate of decline is suspected to be similar. As R. princeps is restricted to swamp forests, yet is generally uniformly abundant within them, the rate of population reduction is inferred to be the same as the rate of habitat reduction. Given that the generation length of R. princeps is estimated at 19–40 years (see Habitat and Ecology section for details), this corresponds to a 57–80% decline in the past 3 generations (57–120 years), if it is assumed that the population was stable between 1824–1944. Thus, across the entire range a population reduction of 42–80% is suspected over the past 3 generations, where the lower estimate assumes that no decline has occurred outside of the Black River region, where data on habitat trends is lacking, while the upper estimate assumes that the rate of habitat reduction in the Negril Morass has been the same as has been calculated for the Black River Morass. We consider the best estimate for the rate of population reduction to be 57–80%, given the likelihood that habitat reduction rates in the Negril Morass have been as high or higher than in the larger Black River Morass.