Mapping and Ecological Assessment of the Posidonia Oceanica Status in the Maloula region, Tabarka

Posidonia oceanica meadows along the Tunisian coast represent a significant ecosystem, providing both ecological and economic benefits.P. oceanica landscapes are heterogeneous, impacted by natural and anthropogenic sources.Our study focuses on sediment analysis and morphological, phenological, and ecological parameters of P. oceanica at nine sites in the Maloula Bay.These sites are categorized into three depths: lower (-3 m), intermediate (-8 m), and upper (-13 m) boundaries.The Posidonia oceanica meadows along the Tunisian coast form a vital ecosystem that provides both ecological and economic benefits.These meadows constitute a heterogeneous landscape influenced by both natural and human activities.Our study examines the morphological and ecological parameters of P. oceanica in nine sites in Maloula Bay.These sites are divided into three depth zones: lower (-3 m), middle (-8 m) and upper (-13 m) limits.Foliar density and morphological parameters (foliar biomass, length, number, leaf category, etc.) show significant values at the lower boundary sites, gradually decreasing with depth.However, epiphyte biomass increases progressively with depth.Furthermore, the examined meadows at the upper and intermediate boundaries (20 years) are older than those at the lower boundary (15 years).In-situ observations and cartographic analysis indicate regressions in the meadows primarily due to natural sources, as evidenced by the Irregularity Source Index (PaSI).These natural regressions manifest as the formation of 'intermatte' sand zones.Other sources such as anchoring and fishing activity may also influence meadow regression.Utilizing surface characteristics and intermediate nature, ecological indices (Conservation Index CI, Overall Quality EQR, and PREI) of the meadows were determined.Despite observed regressions, these indices confirm that the meadows of Maloula Bay are preserved and in "good" condition.