Assessing the Diversity and Spatial Distribution of Sensitive Benthic Macroflora Along the Aegean Coast of Türkiye: An Integrated Ecological Approach

Sensitive benthic macroflora are widely recognized as valuable indicators of ecological quality in coastal ecosystems. This study investigated their diversity and spatial distribution along the Aegean coast of Türkiye and evaluated their relationships with physicochemical variables, nutrient concentrations, and anthropogenic pressures quantified using the Macroalgae-Land Uses Simplified Index (MA-LUSI). A total of 25 coastal stations were surveyed during spring, summer, and autumn 2022, and 91 sensitive taxa were recorded, including 30 brown algae, 52 coralligenous red algae, four green algae, and five seagrasses. Clustered heatmaps based on Bray–Curtis dissimilarity were used to evaluate spatial patterns in community composition using presence–absence and percentage coverage data, whereas Canonical Correspondence Analysis (CCA) was applied to examine the relationships between sensitive phytobenthic communities and environmental variables. The presence–absence heatmap clearly distinguished İzmir-Bostanlı from the remaining stations because of its markedly lower sensitive taxon richness and distinct taxonomic composition. The percentage coverage heatmap also revealed considerable spatial variation among stations, reflecting differences in the abundance and distribution of sensitive habitat-forming taxa. CCA demonstrated clear relationships between sensitive phytobenthic communities and local environmental gradients, with several southern and central Aegean stations being closely associated with sensitive habitat-forming taxa. MA-LUSI values ranged from 0.94 at Gökçeada to 11.25 at İzmir-Bostanlı, indicating pronounced spatial differences in anthropogenic pressure. Overall, the findings demonstrate that sensitive benthic macroflora provide reliable indicators of environmental quality and highlight their importance for the ecological assessment, long-term monitoring, and conservation of coastal ecosystems along the Aegean coast of Türkiye. By identifying areas of ecological degradation, this study also provides a scientific basis for prioritizing conservation and restoration actions in coastal areas exposed to high anthropogenic pressure.