Evaluation of the Ecological Dynamics of the Seagrass Posidonia oceanica in a Turkish Mediterranean Site Considering the Plant Growth

Vascular angiosperms considered as architectures of homogeneity, dominate the composition, and ecosystem functioning in the Mediterranean Sea. Since the realisation of the factors influencing the ecological and evolutionary dynamics of seagrasses, is critical for the conservational purposes, we aimed to evaluate the ecological dynamics Posidonia oceanica meadows in Kızılada, Fethiye-Göcek Special Environmental Protected Area (Muğla, Türkiye) in this study. Considering growth dynamics of the plant, lepidochronological analysis using annual cycles of scale thickness, was conducted both on the orthotropic and the plagiotropic rhizomes. The upper limit of P. oceanica meadows, started from a depth of 18.7 m and ended at a depth of 29.7 m in the region. Development of the plagiotropic rhizomes of P. oceanica along a line from the upper limit to the lower limit depth, could be rarely seen in the Turkish coasts. Since the growth rates were different between orthotrophic and plagiotrophic rhizomes, the annual growth of the meadow on the line, was calculated by averaging the both of the rhizomes. Considering the results, the annual growth rate of P. oceanica decreased with depth and was determined to be minimum at the lower limit depth. The average rate of plagiotropic rhizome elongation, was recorded as 17.8 mm yr-1, while the average of orthotrophic rhizomes was recorded as 8.8 mm yr-1. Lepidochronological analyses verified that P. oceanica meadow was estimated to be approximately 2013 years old according to the average annual growth rate of the rhizomes.