MaxEnt modeling for predicting the present-day and future potential geographical distribution of coral/algae in the Persian Gulf under climate change

Abstract

The Persian Gulf forms a natural geographic barrier to coral reef communities. This study employs MaxEnt modeling with environmental data from Bio-ORACLE to assess the potential distributions of coral/algae and microalgal mats under present conditions and future (2090–2100) scenarios for SSP1, SSP3, and SSP5. Maximum temperature and mixed layer depth were found as the key environmental variables defining habitat suitability. Present-day suitable habitat for coral/algae totals approximately 94,161 km². Under SSP1, a moderate decline of 2.29 % (to ∼92,002 km²) in habitat area is projected. SSP3 scenario shows an increase of 14.32 % (up to ∼107,651 km²), potentially due to local adaptation. In comparison, SSP5 projects a severe 18.14 % decrease (∼77,072 km²) with fragmentation and isolation characterized by a 40 % drop in effective mesh size and 130 % increase in edge density. Microalgal mats exhibited an increasing area and connectivity under more severe scenarios, with the total core area rising from ∼5.2 million to over 16.7 million square units. The largest patch index exceeded 82 %, and the aggregation index peaked near 95 %. Biotic velocity metrics suggested that microalgal mats require movements exceeding 1400 m/year, which is higher than those of coral/algae. North-south direction dominates patterns of change in distribution. These results underscore the need for targeted conservation that prioritizes connectivity and scenario-sensitive management actions in response to climate change in the Persian Gulf.