Vanina Pasqualini

Preliminary data on the impact of fish farming facilities on Posidonia oceanica meadows in the Mediterranean

While the extension of aquaculture along the coasts of the Mediterranean islands is today an economic priority, no data is available on the impact of these facilities on the littoral environment in general, and in particular on the Posidonia oceanica meadows that are responsible for the richness and diversity of these biotopes. The impact of fish farming facilities in the marine littoral environment is assessed at three Mediterranean sites in Corsica and Sardinia. Various parameters are considered: (i) the amount of light available, (ii) the nature of the sediment, and (iii) the vitality of the Posidonia oceanica beds. The findings confirm the impact of the aquaculture facilities within the water column (increase in turbidity, enrichment of the sediment in organic matter and nutrients), and it would appear that the Posidonia oceanica beds also undergo significant alterations. The decline in density of the meadows in the area influenced by aquaculture farming and their total disappearance beneath the facilities is particularly disturbing, even if the areas affected are not very extensive, at least for the smaller farms (a few hundred square metres), and if certain beneficial effects may be recorded (increase in benthic primary production). Because of its ability to record environmental alterations caused by these facilities (light, nutrients, trace metals), the Posidonia oceanica meadow is a good bioindicator for use in monitoring studies.

Long-Term Forest Dynamics and Land-Use Abandonment in the Mediterranean Mountains, Corsica, France

Human practices have had an impact on Mediterranean ecosystems for millennia, particularly through agricultural and pastoral activities. Since the mid-19th century, land-use abandonment has led to the expansion of shrubland and forest, especially in the mountainous areas of the northern Mediterranean basin. Knowledge of these factors is vital to understanding present forest patterns and predicting future forest dynamics in the Mediterranean mountains. We aimed to analyze and understand how land-use abandonment affected spatial modifications of landscapes in two study areas, 44,000 ha and 60,000 ha, located on the island of Corsica, France, representing a typical Mediterranean environment with chestnut forests. Our approach used land-cover archive documents from 1774, 1913, 1975, and 2000, and human population history, 1770 to present day, to describe landscape patterns following land-use abandonment. This research showed that dramatic changes in landscape at the two study areas were caused by the suspension of human influence and the interruption of traditional farming practices. Over the study period, both study sites showed significant reforestation of shrubland and cultivated areas marked by the presence of Quercus ilex forests (+3.40% yr-1 between 1975 and 2000) and by Pinus pinaster (+3.00% yr-1 between 1975 and 2000) at one study site that had experienced heavy rural exodus. At the same time, areas containing chestnut forests decreased by 50% between 1774 and 2000 (-0.09% yr-1 between 1774 and 1975 and -1.42% yr-1 between 1975 and 2000). Shrubland expansion remained limited at both study sites. Our study highlights the value of small-scale approaches for understanding the ecological consequences of land-use abandonment and present and future land-management decisions. Discussion concludes on the importance of working with long-term series for studies on resilience in social-ecological systems and on the consequences in terms of provision of ecosystem services.

Mangrove mapping in North-Western Madagascar using SPOT-XS and SIR-C radar data

Within the framework of an environmental impact study of aquaculture activities in the coastal marsh of Mahajamba (North-Western Madagascar), an assessment of the environmental conditions existing prior to the onset of aquaculture activities (production began in October, 1993) is essential. To this end, the area was mapped using SPOT-XS data, which made it possible to define the main ecodynamic tendencies of the mangroves before the development of the rearing ponds. The aim was then to implement fast, precise and reliable mapping methods, making it possible to follow mangrove alterations resulting from these aquaculture activities. Analysis of the radiometric behaviour of the various plant formations of the marsh, based on SIR-C radar data, revealed that the discrimination between these formations is easier when the frequency used is low and the polarization is crossed. Thematic analysis using textural classification was carried out with the L-band and polarization VH. The results generated are promising insofar as the mapping of mangroves is concerned with a fast treatment time and acceptable precision of the results.

Variations in Allelochemical Composition of Leachates of Different Organs and Maturity Stages of Pinus halepensis

We investigated changes in the occurrence of allelochemicals from leachates of different Pinus halepensis organs taking into account the stages of pine stand age (i.e., young  < 15-years-old, middle age ± 30-years, and old  > 60-years-old). GC-MS analysis of aqueous extracts revealed approx. 59 components from needles and roots. The major constituents were divided into different phytochemical groups—phenolics (50%), fatty acids (44%), and terpenoids. Further analyses were carried out to characterize the distribution of allelochemicals in different organs and P. halepensis successional stages. Roots and needles had two distinct chemical profiles, while needle leachates were composed mainly of oxygenated terpenoids (e.g., α-eudesmol, α-cadinol, and α-terpineol). Roots mainly contained fatty acids. Needles from young pine stands had the highest content of monoterpenes, suggesting their role as potential allelochemicals that could help young pine stands to establish. Pooling the different functional chemical groups showed that needles and, to a lesser extent, old roots, had higher chemical diversity than the roots of young and medium-aged pines. The highest diversity in phenolic constituents and fatty acids was in young needles (Dchem = 2.38). Finally, caffeic acid, a compound that has allelopathic properties was found in aqueous extracts at high concentrations in both young needles and old roots. The role of this compound in mediation of biological interactions in P. halepensis ecosystem functioning is discussed.

Characterization of phenolic compounds in Pinus laricio needles and their responses to prescribed burnings.

Fire is a dominant ecological factor in Mediterranean-type ecosystems. Management strategies include prescribed (controlled) burning, which has been used in the management of several species, such as Pinus nigra ssp laricio var. Corsicana, a pine endemic to Corsica of great ecological and economic importance. The effects of prescribed burning on Pinus laricio have been little studied. The first aim of this study was to characterize total and simple phenolic compounds in Pinus laricio. The second aim was to understand: i) the short term (one to three months) and medium term (three years) effects of prescribed burning, and ii) the effects of periodic prescribed burning on the production of phenolic compounds in Pinus laricio. The first result of this study is the presence of total and simple phenolic compounds in the needles of Pinus laricio. 3-Vanillyl propanol is the major compound. After a prescribed burning, the synthesis of total phenolic compounds increases in Pinus laricio for a period of three months. Total phenolic compounds could be used as bioindicators for the short-term response of Pinus laricio needles to prescribed burning. Simple phenolic compounds do not seem to be good indicators of the impact of prescribed burning because prescribed burnings are low in intensity.

Volatile and semi-volatile organic compounds in smoke exposure of firefighters during prescribed burning in the Mediterranean region

Prescribed fires can be used as a forest management tool to reduce the severity of wildfires. Thus, over prolonged and repeated periods, firefighters are exposed to toxic air contaminants. This work consisted in collecting and analysing smoke released by typical Mediterranean vegetation during prescribed burning. Sampling was performed at five active zones on the island of Corsica. Seventy‐nine compounds were identified: volatile organic compounds and semi‐volatile organic compounds, including polycyclic aromatic hydrocarbons. Depending on exposure levels, the toxins present in smoke may cause short‐term or long‐term damage to firefighters’ health. The dangerous compounds emitted, benzene, toluene, ethylbenzene and xylenes, were quantified. Their concentrations varied as a function of the study site. These variations were due to the intrinsic and extrinsic characteristics of the fire site (e.g. plant species, fire intensity and wind). Our results show that benzene concentration is high during prescribed burning, close to the exposure limit value or short‐term exposure limit. Benzene can be considered as a toxicity tracer for prescribed burning because its concentration was above the exposure limit value at all the study sites. The authors suggest that respirators should be used to protect staff during prescribed burning operations.

A GIS-Based Multicriteria Evaluation for Aiding Risk Management Pinus pinaster Ait. Forests: A Case Study in Corsican Island, Western Mediterranean Region

Forest management can benefit from decision support tools, including GIS-based multicriteria decision-aiding approach. In the Mediterranean region, Pinus pinaster forests play a very important role in biodiversity conservation and offer many socioeconomic benefits. However, the conservation of this species is affected by the increase in forest fires and the expansion of Matsucoccus feytaudi. This paper proposes a methodology based on commonly available data for assessing the values and risks of P. pinaster forests and to generating maps to aid in decisions pertaining to fire and phytosanitary risk management. The criteria for assessing the values (land cover type, legislative tools for biodiversity conservation, environmental tourist sites and access routes, and timber yield) and the risks (fire and phytosanitation) of P. pinaster forests were obtained directly or by considering specific indicators, and they were subsequently aggregated by means of GIS-based multicriteria analysis. This approach was tested on the island of Corsica (France), and maps to aid in decisions pertaining to fire risk and phytosanitary risk (M. feytaudi) were obtained for P. pinaster forest management. Study results are used by the technical offices of the local administration—Corsican Agricultural and Rural Development Agency (ODARC)—for planning the conservation of P. pinaster forests with regard to fire prevention and safety and phytosanitary risks. The decision maker took part in the evaluation criteria study (weight, normalization, and classification of the values). Most suitable locations are given to target the public intervention. The methodology presented in this paper could be applied to other species and in other Mediterranean regions.

Variability of Ruppia cirrhosa in two coastal lagoons with differing anthropogenic stresses

Abstract The dynamics of Ruppia cirrhosa were studied over two years in two coastal lagoons on the Corsican coast (France, Mediterranean Sea). The lagoons differed in type of eutrophication: (1) Biguglia lagoon (urban and industrial effluent, agriculture, runoff from catchment area) and (2) Santa Giulia lagoon (tourist pressure in summer). Spatio-temporal variability of R. cirrhosa occurrence was monitored on permanent transects. We also monitored temporal changes in density, aboveground/belowground biomass and organic matter. Most of the parameters studied along the transects show variations with season and site. Density and aboveground biomass of R. cirrhosa in Biguglia lagoon were lower when Ulva species were present. This may be related to differences in nutrient availability. During the first year of the study, rainfall was greater with concomitantly higher nutrient inputs, which may account for the higher values of measured parameters in the first year. The results suggest that environmental parameter variations affect the functioning of R. cirrhosa meadows.

Contrasting Patterns of Phytoplankton Assemblages in Two Coastal Ecosystems in Relation to Environmental Factors (Corsica, NW Mediterranean Sea)

Corsica Island is a sub-basin of the Northwestern Mediterranean Sea, with hydrological features typical of both oligotrophic systems and eutrophic coastal zones. Phytoplankton assemblages in two coastal ecosystems of Corsica (the deep Bay of Calvi and the shallow littoral of Bastia) show contrasting patterns over a one-year cycle. In order to determine what drives these variations, seasonal changes in littoral phytoplankton are considered together with environmental parameters. Our methodology combined a survey of the physico-chemical structure of the subsurface water with a characterization of the phytoplankton community structure. Sampling provided a detailed record of the seasonal changes and successions that occur in these two areas. Results showed that the two sampled stations presented different phytoplankton abundance and distribution patterns, notably during the winter–spring bloom period. Successions in pico-, nano-, and microphytoplankton communities appeared mainly driven by differences in the ability to acquire nutrients, and in community-specific growth rates. Phytoplankton structure and dynamics are discussed in relation to available data on the Northwestern Mediterranean OPEN ACCESS Diversity 2014, 6 297 Sea. These results confirm that integrated monitoring of coastal areas is a requisite for gaining a proper understanding of marine ecosystems.

Use of remote sensing for the characterization of the Mediterranean coastal environment—the case of Posidonia oceanica

The beds ofPosidonia oceanica, a marine vascular plant species endemic to the Mediterranean, form a major Mediterranean marine ecosystem. These beds are well-developed along the sandy east coast of Corsica, where the continental shelf is wide and extends for ca. 100 km. The upper limit of this ecosystem has been mapped by means of a computer image processing technique using 1/20 000 colour photographs. One of the major problems for image processing in the marine environment is the impact of the water layer (of variable thickness and quality), which can result in variations of the spectral signature for a particular vegetation or bottom type. In an attempt to reduce the impact of this artefact, a processing technique that takes into account bathymetric factors has been tested. Cartographical data obtained for an area extending from Bastia to Solenzara are presented. In the vicinity of the mouths of coastal rivers, a systematic indentation of the upper limit of the seagrass beds has been revealed. On the basis of these results, local variations in the quality of the marine environment can be detected, in particular with regard to salinity, turbidity and/or the impact of sedimentation. The overall surface area of thePosidonia oceanica beds has also been calculated.