State of health of Posidonia oceanica meadows along the northern Tyrrhenian coast of Calabria, Italy (original) (raw)
Related papers
CHANGE IN THE PHYTOBENTHOS SETTLEMENT ALONG THE SANTA LIBERATA COAST (SOUTHERN TUSCANY, ITALY)
A stretch of coast of 40 Km (from Porto S. Stefano-Mt. Argentario to the Chiarone River) was monitored in June and July 2004 for presence, range, biomass and biometry of meadows of Posidonia oceanica. The survey was made by videocamera along 30 transects and quantitative samples were taken from 15 of the 30 transects, at the upper and lower limits (UL, LL). The data were analyses by ANOVA and MDS. Shoot density suggested widespread conditions of "normal density", while the Leaf Area Index at UL (11.9 ± 5.2 m 2 ·m -2 ) and LL (9.5 ± 4.1 m 2 ·m -2 ) and the Leaf Standing Crop at UL (1006,8 ± 389,8 gdw·m -2 ) and LL (637.1 ± 528.0 gdw·m -2 ) showed high values. The deepest LL was -28.5 m and the mean was -20.6±5.6 m. Between UL and LL, the percentage of bottom covered by meadow varied between 10 and 80, with a mean of 51.1 ± 20.5 %. Three of the sites sampled were relatively worse than the others. In two cases, it could be ascribed to a bottom consisting mostly of sandstone detritus; in the third site it could be due to erosion and bottom trawling. Meadow range along Mt. Argentario was limited by the steep slope of the coast, which drops sharply to depth below the lower limit of P. oceanica.
2020
The ecological structure of Posidonia oceanica (L.) Delile meadows was evaluated on the northern coast of Lazio, Italy (central Tyrrhenian, Mediterranean sea). This is an infra-littoral zone with a wide range of anthropogenic activities and high geo-morphological variability, which reflects heterogeneity in shoot density, leaf morphology and biomass in fragmented patches. Genetic variability in populations corresponds to the formation of 3 sub-clusters, in the diverse impacted zones (north, centre and south), being correlated to the geographical distance between sites. AMOVA estimated a high genetic variation showing 43.05% individual differences within populations with a marked differentiation among the populations (56.9%) indicated by Fst value (0.57). These results revealed the role of the genetic structure of seagrasses for determining selectivity of fragmented habitat, in response to natural drivers. They showed that site-specific self-recruitment is related to biodiversity capacity and to the geo-morphological characteristic of the coast.
Mediterranean Marine Science, 2014
The impact of fish farming activities on Posidonia oceanica meadows in the Aegean Sea have been detected by using bryozoan epiphytes as indicators of disturbance. Samples were collected by SCUBA diving in September 2004 for comparing assemblages between disturbed (I1:0-5 m; I2:5-10 m and I3:10-15 m) and control meadows (C1:0-5 m; C2:5-10 m and C3:10-15 m) located at different depths. Regarding to mean percentage cover of bryozoans, significant differences were found between stations, leaf sides, depths and their interactions (p<0.05). Bryozoan species were colonized densely on back side of the adult leaves. Bantariella verticillata, Alcyonidium sp., Aetea truncata, Chorizopora brongniartii, Fenestrulina joannae were frequently observed species on P. oceanica leaves. B. verticillata showed statistically significant side and station differences while other species showed only significant side differences. Moreover, the mean coverage of Aetea truncata showed neither station nor side...
Italian Botanist
The ecological structure of Posidonia oceanica (L.) Delile meadows was evaluated on the northern coast of Lazio, Italy (central Tyrrhenian, Mediterranean sea). This is an infra-littoral zone with a wide range of anthropogenic activities and high geo-morphological variability, which reflects heterogeneity in shoot density, leaf morphology and biomass in fragmented patches. Genetic variability in populations corresponds to the formation of 3 sub-clusters, in the diverse impacted zones (north, centre and south), being correlated to the geographical distance between sites. AMOVA estimated a high genetic variation showing 43.05% individual differences within populations with a marked differentiation among the populations (56.9%) indicated by Fst value (0.57). These results revealed the role of the genetic structure of seagrasses for determining selectivity of fragmented habitat, in response to natural drivers. They showed that site-specific self-recruitment is related to biodiversity cap...
2020
The ecological structure of Posidonia oceanica (L.) Delile meadows was evaluated on the northern coast of Lazio, Italy (central Tyrrhenian, Mediterranean sea). This is an infra-littoral zone with a wide range of anthropogenic activities and high geo-morphological variability, which reflects heterogeneity in shoot density, leaf morphology and biomass in fragmented patches. Genetic variability in populations corresponds to the formation of 3 sub-clusters, in the diverse impacted zones (north, centre and south), being correlated to the geographical distance between sites. AMOVA estimated a high genetic variation showing 43.05% individual differences within populations with a marked differentiation among the populations (56.9%) indicated by Fst value (0.57). These results revealed the role of the genetic structure of seagrasses for determining selectivity of fragmented habitat, in response to natural drivers. They showed that site-specific self-recruitment is related to biodiversity capacity and to the geo-morphological characteristic of the coast.
Aquatic Botany, 2013
We investigated the impact of sewage discharge on Posidonia oceanica meadows in Eastern Tunisia (Mahdia). We specifically addressed changes in plant growth and epiphyte composition on leaves and rhizomes caused by this anthropogenic interference. A hierarchical sampling design was used to compare epiphyte biomass and community structure between one disturbed and two control stations. Samples were collected by SCUBA diving at 8 m depth in August 2009. A total of 44 taxa, macroinvertebrates and macroalgae, were identified on rhizomes, and 27 taxa on leaves. In the disturbed station, leaf length, leaf surface area and the leaf area index decreased, whereas epiphyte biomass increased compared to the control stations. Rhizome epiphyte coverage differed significantly between the control stations and the disturbed station, mainly due to changes in green, red and brown algae, bryozoans, and ascidians. Leaf epiphyte coverage differed between stations, with more red algae and ascidians on leaves of the disturbed station and more, green and brown algae at the control stations. SIMPER and CCA analyses showed that differences were due to the absence of some species at the control stations, which exhibited a high coverage at the polluted station. In summary, waste water pollution caused a severe deterioration of seagrass meadow vitality, possibly due to an increased epiphyte cover and associated changes in epiphyte community composition on leaves and rhizomes of P. oceanica.
2006
The La Maddalena archipelago became national Park in 1996 and together with the southern part of corsica it forms the Bocche di Bonifacio international Park. posidonia oceanica beds widely distributed in the area play an important role in dividing La Maddalena national Park (MnP) into zones with different level of protection in order to manage and coordinate the human activities inside the park. The regression of p. oceanica meadows has become generalised around much of thearchipelago coastline.The most common anthropogenic factors in the decline of P. oceanica habitats in near-shore coastal areas are eutrophication and boat anchoring.
Chemistry and Ecology, 2010
An update of the spatial distribution and bio-ecological features of Posidonia oceanica (L.) Delile meadows spread along the coasts of the southern Adriatic and northern Ionian Seas (Apulia region, southern Italy) is reported. Mapping carried out in 2004 indicated a remarkable reduction in the spatial distribution of P. oceanica meadows in the southern Adriatic Sea, mostly northwards of Bari, when compared with 1991 data. By contrast, in the northern Ionian Sea, the spatial distribution seems to be more stable. The P. oceanica meadows covered ∼330 km 2 distributed along a total of 320 linear km coastline, mostly on the southern side of Apulia. Within natural variability, the differences in bio-ecological features could be due mainly to the presence of anthropic disturbance (urban, industrial and tourist pressure) rather than a significant geographical gradient between the Adriatic and Ionian Seas. However, the mean density values recorded in almost all theAdriatic stations fall within the 'lower sub-normal density'(LSD) range. By contrast, the mean density values observed in the Ionian meadows were generally within the 'normal density' (ND) range.
Open Journal of Ecology, 2011
The conservation status of the Posidonia oceanica meadow at Santa Marinella (Rome) was evaluated through both standard (bed density, leaf biometry, "A" coefficient, Leaf Area Index, rhizome production) and biochemical/genetic approaches (total phenol content and Random Amplified Polymorphic DNA marker). The biochemical/genetic results are in agreement with those obtained by standard approaches. The bed under study was ranked as a disturbed one, due to its low density, and high heterogeneity in leaf biometry, LAI values, "A" coefficient and primary production. This low quality ranking is confirmed by both mean phenol content in plants, quite high and scattered, and by the low genetic variability in the meadow, with a very high similarity of specimen at a local scale. Hence, these two putative approaches clearly identify the endangered conservation status of the meadow. They link plant biodiversity and ecophysiology to ecosystem 'health'. Furthermore, they are repeatable and standardizable and could be usefully introduced in meadows monitoring to check environmental quality.
The health status of an emerging Posidonia oceanica meadow, subject to high human impact, was studied. Biometric variables, heavy metals, PAHs and C, N, P contents were determined in sediment and seagrass samples. The meadow was found to grow under oligotrophic conditions and an increase in nutrient content was only recorded in autumn. In sediment, Hg exceeded its ERL (effects range low) and sometimes also its ERM (effects range medium), and Cu was close to its ERL. In leaves, Hg and Cu were relatively high but below their respective ERLs. Sediments close to the meadow were heavily contaminated with pyrolytic PAHs, some of which exceeded their ERLs. P. oceanica did not show major accumulation of PAHs, lighter molecules predominating. Despite 40 years of intense human activity, meadow growth dynamics and contaminant accumulation did not suggest that the meadow was regressing.