Posidonia oceanica (L.) Delile at Its Westernmost Biogeographical Limit (Northwestern Alboran Sea): Meadow Features and Plant Phenology

Abstract

Meadows of the seagrass Posidonia oceanica inhabit most infralittoral bottoms of the Mediterranean Sea and are considered one of the main climax stages of the infralittoral environment. This seagrass has its western distributional limit along the coast of the Alboran Sea. Taking into account the decline of P. oceanica meadows and the global scenario of ocean warming, it becomes essential to know the structure, temporal dynamics, sexual reproduction and conservation status of this seagrass, across its geographical distribution, including the distribution boundaries where the meadows withstand limiting environmental conditions. In the present work, we studied the structure, phenology and flowering events of four P. oceanica meadows located in the northwestern Alboran Sea (close to the Strait of Gibraltar). Results indicate a decreasing trend of patch size, bathymetric range and number of leaves per shoot towards the Strait (and the Atlantic Ocean), as well as an increasing trend of shoot density and leaf height. Phenological parameters of the northwestern Alboran Sea P. oceanica meadows presented temporal dynamics similar to meadows from other locations within the biogeographical distribution of this seagrass, with similar or even less annual variability in the former. Although most of the studied P. oceanica meadows seem to present a good health status (BiPo index ~0.6) with high shoot densities and some flowering events, some of them showed evidence of regression.

A Package of Script Codes, POSIBIOM for Vegetation Acoustics;<em> POSIdonia</em> BIOMass

“…Like other seagrasses, Posidonia species are near coastal inhabitants giving many useful opportunities to the other organisms under their canopies [4,[12][13][14][15]. One of the common Posidonia species is Posidonia oceanica (Linnaeus) Delile, 1813 which is an endemic species for the Mediterranean Sea extending to near coast of the eastern Atlantic Ocean [16]. Most (25-30%) of the Mediterranean coasts are inhabited by P. oceanica [6].…”

A Package of Script Codes, POSIBIOM for Vegetation Acoustics: POSIdonia BIOMass

“…Like other seagrasses, Posidonia species can provide many useful habitats for other organisms under its canopies [4,[12][13][14][15]. One of the most common Posidonia species is Posidonia oceanica (Linnaeus) Delile, 1813, which is an endemic species found in the Mediterranean Sea and extending to the near shore of the eastern Atlantic Ocean [16]. Most (25-30%) Mediterranean coasts are inhabited by P. oceanica [6].…”