Assessing the impact of climate change on the potential distribution of the Carthaginian tree frog (Hyla carthaginiensis): a species distribution modelling approach integrating different dispersal scenarios

The Carthaginian tree frog, Hyla carthaginiensis, is an endemic species confined to northern Tunisia and north-eastern Algeria. The species is known for its limited dispersal ability and its sensitivity to heat and water stress. With climate change and the latent rise in temperatures, the species could face potential hazards, thereby increasing its susceptibility. This study, therefore, sought to assess the impact of climate change on the potential distribution of Hyla carthaginiensis using climate projections from three global circulation models and two socio-economic pathways (SSP3-7.0 and SSP5-8.5) for 2050. The maximum entropy (MaxEnt) model was developed using six bioclimatic variables and 120 occurrence locations. The future prediction models were adjusted based on three dispersal scenarios, namely 'fixed rate dispersal', 'limited dispersal' and 'no dispersal'. The current model predicted approximately 6,784 km(2) as suitable habitat for the species, with only 7% occurring above 500 m. Projections for the future range exhibited a gradual decline ranging from 64 to 90%, depending on the SSP and dispersal scenario used. The most drastic decline is projected under SSP585 and the no dispersal scenario, potentially losing 90% of the current range by 2050. According to this dispersal scenario, habitats below 250 m altitude are likely to be lost, possibly leading to an altitudinal shift that could confine the species to mountaintops. Our results provide further evidence of the negative impact of climate change on endemic amphibians and emphasise the importance of considering diverse dispersal scenarios in their conservation.