Mediterranean Coastal Habitats Research Articles

Dune plants as a sink for beach litter: The species-specific role and edge effect on litter entrapment by plants

Anthropogenic litter accumulates along coasts worldwide. In addition to the flowing litter load, wind, sea currents, geomorphology and vegetation determine the distribution of litter trapped on the sandy coasts. Although some studies highlighted the role of dune plants in trapping marine litter, little is known about their efficiency as sinks and about the small-scale spatial distribution of litter across the dune area. Here, we explore these gaps by analysing six plant species widespread in Mediterranean coastal habitats, namely Echinophora spinosa, Limbarda crithmoides, Anthemis maritima, Pancratium maritimum, Thinopyrum junceum, and Salsola kali. The present study analyses for the first time the capture of litter by dune vegetation at a multi-species level, considering their morphological structure. Data on plastic accumulation on dune plants were compared with unvegetated control plots located at embryo-dune and foredune belts. We found that dunal plants mainly entrapped macrolitter (> 0.5 cm). Particularly, E. spinosa, L. crithmoides, A. maritima and P. maritimum mostly accumulated litter in the embryo dune while T. junceum and S. kali entrapped more in the foredune area. Moreover, beach litter was mainly blocked at the edge of the plant patches rather than in the core, highlighting the ‘Plant-edge litter effect’. As A. maritima and S. kali entrapped respectively more litter in embryo and foredune habitats, these species could be used to monitor and recollect litter. In this light, our findings provide further insight into the role of dune plants in the beach litter dynamics, suppling useful information for beach clean-up actions.

A multidisciplinary integrated approach using Pachygrapsus marmoratus to assess the impact of port activities on mediterranean marine protected areas

The establishment of marine protected areas is considered the main global strategy to halt the loss of marine biodiversity. Since most of marine areas are open systems, this form of habitat protection cannot prevent their contamination due to human activities performed outside of their borders. Innovative approaches to assess the health status of protected marine habitats are therefore needed. Here we developed a multidisciplinary approach that combines ecological characteristics, bioaccumulation of inorganic and organic pollutants, cell damage (micronuclei frequency, nuclear alterations and LPO) and enzymatic (AChE, CAT, IDH, LDH, GST and CAT) markers focused on an intertidal brachyuran crab, Pachygrapsus marmoratus, to assess the impacts of contaminant exposure on Mediterranean coastal habitats. As study sites we selected two protected areas and two sites within industrial ports of the Ligurian Sea. Our results showed that the selected crab species is an excellent bioindicator. Individuals collected in sites with the highest levels of heavy metal pollution showed the highest signals of stress responses at both cellular and enzymatic levels, coupled with a high incidence of the parasite Sacculina carcini, a signal of impairment of their standard development and reproduction cycle. We could also prove that one of the selected marine protected areas showed the same intensity of impact as its adjacent port site. Our multidisciplinary approach proved to be a valuable tool to assess the environmental quality and health of protected and disturbed Mediterranean coastal environments and to inform efficient management and protection schemes for such habitats.

Effectiveness of protected areas against land development in coastal areas of the Mediterranean global biodiversity hotspot

The Mediterranean Basin is a heavily pressured World biodiversity hotspot. Mediterranean coastal areas are especially threatened due to tourism, inland migration and population growth, jeopardizing the remaining natural habitats. Protected areas (PAs) aim to conserve biodiversity and ecosystem services in the long term. Here, we assessed whether coastal PAs in 16 Mediterranean countries had been effective at conserving natural habitats from land development between 2000 and 2020, using a Before-After-Control-Impact design with covariates and case-control matching in R. Mediterranean coastal PAs were effective in reducing land development, with just one exception: Israel. Legally stringent reserves were generally more effective than legally lenient multiple-use PAs, with few exceptions: Albania, France and Cyprus. In a number of countries, reserves completely prevented coastal land development, which shows that reserves are a useful tool to preserve waning Mediterranean coastal habitats. Institutional, social, economic and geographic explanatory factors were analysed for PA effectiveness at country scale, but no significant results were found, suggesting high specificity of PA effectiveness.

The Status of Posidonia oceanica at Tremiti Islands Marine Protected Area (Adriatic Sea).

Simple SummaryThe seagrass Posidonia oceanica is the most important marine phanerogam of the Mediterranean Sea due to its meadows’ complexity, persistence, and extension. These habitats provide a suite of ecosystem goods and services, being of primary importance in marine conservation. Despite their central role in the coastal ecology, P. oceanica meadows are undergoing overall deterioration and fragmentation in the basin mostly due to anthropogenic impacts at local to global scales. In the last decades, several management measures have been proposed aiming to improve the meadow health conditions, while the periodic monitoring of P. oceanica meadows allows for verifying their effectiveness. Here, we report the results of the monitoring of P. oceanica at Tremiti Islands Marine Protected Area (Adriatic Sea, Italy) carried out in 2003, 2015, and 2020. A general worsening was observed, particularly enhanced by direct anthropogenic impacts mostly related to anchoring practices, as well as by a certain level of sedimentation possibly deriving from coastal development. However, the identification of these impacts and the correct management of human activities to mitigate them produced positive results in a relatively short time span.Posidonia oceanica meadows are Mediterranean coastal habitats of great conservation importance. This study is focused on a meadow located at Tremiti Islands Marine Protected Area (Adriatic Sea, Italy), which was monitored in 2003, 2015, and 2020 to evaluate its health state over time in relation to coastal human activities, which have been highly affecting this MPA for the last 20 years. To assess any change in the physiognomy of the meadow, rhizome density, percentage coverage, and lower limit progressions and/or regression over time were evaluated by scuba diving, while the distribution and extension of the meadow were assessed through habitat mapping using a side-scan sonar. Moreover, phenological and lepidochronological analyses were performed on the collected rhizomes to assess the leaf area index (LAI, m2m−2) and the rhizome age (lepidochronological years). Our study showed a general deterioration of P. oceanica meadow from 2003 to 2020, with a significant reduction of its absolute and relative rhizome density and LAI at almost all sampling stations, absence of renovation of the meadow, and lower limit regression and overall worsening of the main conservation status indicators. However, appropriate management actions, such as the establishment of mooring buoy fields, supported the improvement of the P. oceanica status at the local scale with a significant increase in density and LAI and the presence of active stolonization processes, suggesting that mitigation actions can play a crucial role in the conservation of this habitat. On the contrary, local anthropogenic impacts, especially anchoring and coastal development, markedly affect the resilience of P. oceanica meadows to global stressors, such as climate change.

An endangered species living in an endangered ecosystem: Population structure and growth of European eel Anguilla anguilla in a Mediterranean coastal lagoon

Mediterranean coastal habitats constitute a nonmarginal fraction of the overall continental habitats of the European eel. It has been suggested that the recovery of the eel global stock may depend closely upon the contribution of Southern European and North African countries within the Mediterranean basin, therefore It is essential to know all the aspects related with its biology and populations dynamic to ensure that the European Commission conservation plan works in this habitats. The aims of this study were to ascertain the structure of the endangered A. anguilla populations in the Mar Menor and obtain essential data for future management plans in the Mediterranean catchment area. In total, 1151 wild fish were caught by local fishermen in 2015–2016 and 2016–2017, and their biological traits were determined. Our findings show that the Mar Menor’s A. anguilla population consists of resident females (1:0.008, female:male), yellow and silvering individuals (56.56% and 43.27% respectively), with a mean age of 3 years. The traditional view of long-lived eels with low growth rates does not fit the picture of Mediterranean eel populations. The effect of fishing techniques used, and the eutrophication processes noted during the study period are also discussed.

Measuring Alpha and Beta Diversity by Field and Remote-Sensing Data: A Challenge for Coastal Dunes Biodiversity Monitoring

Combining field collected and remotely sensed (RS) data represents one of the most promising approaches for an extensive and up-to-date ecosystem assessment. We investigated the potential of the so called spectral variability hypothesis (SVH) in linking field-collected and remote-sensed data in Mediterranean coastal dunes and explored if spectral diversity provides reliable information to monitor floristic diversity, as well as the consistency of such information in altered ecosystems due to plant invasions. We analyzed alpha diversity and beta diversity, integrating floristic field and Remote-Sensing PlanetScope data in the Tyrrhenian coast (Central Italy). We explored the relationship among alpha field diversity (species richness, Shannon index, inverse Simpson index) and spectral variability (distance from the spectral centroid index) through linear regressions. For beta diversity, we implemented a distance decay model (DDM) relating field pairwise (Jaccard similarities index, Bray–Curtis similarities index) and spectral pairwise (Euclidean distance) measures. We observed a positive relationship between alpha diversity and spectral heterogeneity with richness reporting the higher R score. As for DDM, we found a significant relationship between Bray–Curtis floristic similarity and Euclidean spectral distance. We provided a first assessment of the relationship between floristic and spectral RS diversity in Mediterranean coastal dune habitats (i.e., natural or invaded). SVH provided evidence about the potential of RS for estimating diversity in complex and dynamic landscapes.

Rapid continental spread of a salt-tolerant plant along the European road network

The spread of alien species with the expansion of road networks and increasing traffic is a well-known phenomenon globally. Besides their corridor effects, road maintenance practices, such as the use of de-icing salts during winter facilitate the spread of halophyte (salt tolerant) species along roads. A good example is Plantago coronopus, a mainly coastal halophyte which has started spreading inland from the Atlantic and Mediterranean coastal habitats, recently reaching even Central European countries (e.g. Hungary). Here we studied the spread of this halophyte and tried to identify factors explaining its successful dispersion along roads, while also comparing native and non-native roadside occurrences with regard to altitude of the localities, size of roadside populations and frequency of roadside occurrences. We completed a comprehensive literature review and collected more than 200 reports of occurrence from roadsides spanning a total of 38 years. During systematic sampling the frequency of the species along roads was significantly higher in the Mediterranean (native area), than along Hungarian (non-native area) roads, however the average number of individuals at the sampling localities were very similar, and no significant difference could be detected. Using a germination experiment, we demonstrate that although the species is able to germinate even at high salt concentrations, salt is not required for germination. Indeed salt significantly decreases germination probability of the seeds. The successful spread of the species could most likely be explained by its remarkably high seed production, or some special characteristics (e.g. seed dimorphism) and its ability to adapt to a wide range of environmental conditions. Considering the recent and rapid eastward spread of P. coronopus, occurrences in other countries where it has not been reported yet can be predicted in coming years.

Getting the measure of the biodiversity crisis in Mediterranean coastal habitats

Abstract Assessing temporal changes in plant communities is a core aim of temporal ecology and a shared priority of global conservation agendas which is particularly urgent in threatened ecosystems. Mediterranean coastal dunes harbour some of the most threatened habitats in Europe. Yet, surprisingly, studies capturing the recent temporal dynamics of biodiversity in these systems by accounting for multiple diversity facets and different aspects of community structure are missing. Here, using data from a resurveying study, we provide a first comprehensive, habitat‐based, multi‐faceted assessment of recent (10–15 years) temporal changes in threatened Mediterranean coastal dunes. To this aim, we quantified taxonomic and functional changes in plant communities using indices capturing multiple biodiversity features, and we explored trends at both the community level and the species level. We compared observed biodiversity changes across habitats (to look for evidence of generalized biodiversity loss) and across facets (to infer the potential loss of unique functions), and tested their significance using a null model. Overall, we predicted large compositional shifts and biodiversity loss beyond expectations in many communities, although with differences among habitat types. Our results reveal severe shifts in the taxonomic profile of the communities, mostly driven by a non‐random species loss, and little temporal overlap in functional space, implying large changes in both community structure and ecological strategies of the investigated habitats. This, together with the disappearance of c. 23% of historical plots and with substantial losses in focal species, suggests that intense degradation processes are occurring in coastal dune habitats, particularly on the upper beach and on shifting dunes. Synthesis. This study provides the first evidence of large, often non‐random, taxonomic and functional changes occurring in Mediterranean coastal dune plant communities in a surprisingly short time‐span. Along with furthering our knowledge of the recent dynamics affecting these endangered ecosystems, our results also pinpoint the types of habitats that are most at risk, helping to direct future conservation efforts and management. Future research should now be directed at more precisely testing potential drivers of these changes.

Effectiveness of the Natura 2000 network in conserving Mediterranean coastal dune habitats

Though protected areas are recognized as the cornerstone of global conservation efforts, their effectiveness in safeguarding biodiversity is currently debated. In particular, studies evaluating the counterfactual influence of protection status on community metrics derived from field-collected data are still scarce.In this paper, using data from a resurveying study, we assessed the contribution of the European Natura 2000 network to maintaining and/or improving through time habitat quality and functional integrity in Mediterranean coastal dune habitats, which appear among the most threatened ecosystems worldwide. Using multiple regression techniques, we tested the influence of protection status on habitat loss and on 10–15 years changes in the richness and cover of two highly informative plant groups: focal and alien species. Next to a substantial habitat loss, we observed an overall decrease in focal species richness and cover, whereas alien species were stable or slightly increasing, depending on the habitat.Surprisingly, changes in the analyzed metrics did not differ between protected and non-protected sites, thus providing no substantial evidence of the effectiveness of Natura 2000 in conserving and/or improving dune habitats. Taken together, such results suggest negative implications for the whole ecosystem structure and functionality, to be expected regardless of the protection status.This led us to reflect about the general inadequacy in the implementation of actual conservation measures in coastal habitats, discuss potential causes (lack of ad-hoc management plans and targeted conservation measures, scarcity of dedicated funding, bureaucratization), and stress the value of monitoring activities for evaluating conservation outcomes and reformulating current strategies.

The impact of Acacia saligna and the loss of mobile dunes on rodent populations: a case study in the Ashdod-Nizzanim sands in Israel

The Mediterranean coastal dune habitat of Israel is diminishing rapidly, mostly due to massive urbanization, changes in habitat characteristics caused by dune stabilization and the presence of Acacia saligna, an invasive species brought to Israel for the purpose of dune stabilization. In this study we document the effect of sand stabilization on the composition of small mammal communities in the Ashdod-Nizzanim sands, Israel. We analyzed differences in species diversity and abundance for species of rodents in four types of habitat: unstable (mobile) sand dune, semi-stabilized dune, inter-dune depression and a plot of the invasive Acacia saligna. Rodent communities were found to undergo gradual changes concurrently with the stabilization of the sands. The mobile dune was the only habitat in which the strict psammophiles Jaculus jaculus and Gerbillus pyramidum were captured in abundance. No species commensal with human were captured neither in the mobile nor in the semi-stabilized dunes. However, in the inter-dune depression there was quite a large representation of Mus musculus, a rodent commensal with humans. The Acacia saligna plot had the lowest number of captures and the lowest rodent biomass calculated, with Mus musculus composing nearly half of the captures. The results of this study demonstrate that stabilization of the sands in Ashdod-Nizzanim area is associated with the disappearance of psammophile rodents and the appearance of species commensal with humans. In order to preserve the habitat for psammophile rodents, measures should be taken to halt the spread of acacia and the continuing stabilization of the sands.

Conservation status of Mediterranean coastal dune habitats: anthropogenic disturbance may hamper habitat assignment

Coastal dunes are rich in habitats with a high heterogeneity in species composition. Though widely recognized as very fragile and dynamic ecosystems, they are systematically overexploited. In addition, mismanagement contributes making these habitats highly endangered, especially in the Mediterranean area. In this study, an impoverished dune system was used to investigate whether the lack of indicator species, including characteristic, main diagnostic, alien and non-typical, could mislead habitat assignment. Coastal dune plant communities used in this study are embedded into a high anthropogenic pressure territory, primarily due to the vicinity to a city and by hosting bathing facilities. A cluster analysis based on 49 vegetation plots (releves) was performed in order to assign dune vegetation units to EU habitats (92/43/EEC Habitat Directive) and corresponding phytosociological units. Eight habitat types were classified and two of them were of priority importance. Twelve plant communities belonging to eight different phytosociological classes were recognized. The plant cover value of characteristic, main diagnostic, alien and non-typical plant species, was used to assess the conservation status of each habitat type. Despite the presence of well-preserved plant community, almost all habitats were in unfavourable conservation status. Furthermore, a floristic impoverishment and a zonation interruption on the stabilized dunes were found. This study underlines the difficulty to identify typical coastal dune plant communities and associated habitats when anthropogenic disturbance dramatically changes the environmental conditions. Specific conservation and management actions for the sustainable maintenance of these endangered habitats are suggested.

On the use of Sentinel-2 for coastal habitat mapping and satellite-derived bathymetry estimation using downscaled coastal aerosol band

Coastal habitats provide a plethora of ecosystem services, yet they undergo continuous pressure and degradation due to the human-induced climate change. Conservation and management imply continuous monitoring and mapping of their spatial distribution at first. The present study explores the capabilities of the Copernicus Sentinel-2 mission and the contribution of its coastal aerosol band 1 (443 nm) for the mapping of the dominant Mediterranean coastal marine habitats and the bathymetry in three survey sites in the East Mediterranean. The selected sites have shallow to deep habitats and a high variability of oceanographic and seabed morphological conditions. The major findings of our study demonstrate the advantages of the downscaled Sentinel-2 coastal aerosol band 1 for both optically shallow habitat and satellite-derived bathymetry mapping due to its great water penetration. The use of Sentinel-2 band 1 allows detection of Posidonia oceanica seagrass beds down to 32.2 m of depth. Sentinel-2 constellation with its 10-m spatial resolution at most of the spectral bands, 5-day revisit frequency and open data policy can be an important tool to provide crucial missing information on the spatial distribution of coastal habitats and on their bathymetry distribution, especially in data-poor and/or remote areas with large gaps in a retrospective, rapid and non-intrusive manner. As such, it becomes a crucial ally for the conservation and management of coastal habitats globally.

Pollination insights for the conservation of a rare threatened plant species, Astragalus tragacantha (Fabaceae)

The increase in habitat fragmentation impacts plant-pollinator interactions and threatens the sustainability of plant species. Astragalus tragacantha (Fabaceae), is a rare endangered plant species along the coastal habitats where the plant populations have undergone considerable fragmentation and decline of size. Controlled pollination treatments, the observation of pollinator activity, and pollinator captures, have been conducted to study: (1) the mating system of A. tragacantha and the potential for inbreeding depression and/or outbreeding depression based on controlled pollination treatments, (2) the pollinator composition among populations using a correspondence analysis and a hierarchical clustering, and (3) the link between pollinators and the plant reproductive success using a path-analysis model. In this study, we demonstrated that this plant was not autogamous self-pollinating and depended on pollinators for its reproduction. The absence of difference between manual and open pollinations regarding the reproductive success showed an absence of pollen limitation in our populations. We showed that populations differed in the composition of their pollinator guilds. Some pollinator species were predominant in certain populations. The pollination treatments revealed the existence of a mixed mating system in A. tragacantha populations. We showed an inbreeding depression potentially linked to a predominant pollinator-facilitated selfing, and the existence of outbreeding depression between some distant populations. These differences in pollinator guild and plant mating systems among populations must be considered during the restoration of populations along the Mediterranean coastal habitats in order to enhance the reproductive success and sustainability of A. tragacantha.

Seasonal and daily variations in primary and secondary metabolism of three maquis shrubs unveil different adaptive responses to Mediterranean climate.

Maquis species play a central role in the maintenance of coastal ecosystems thanks to anatomical, physiological and biochemical features evolved to cope with severe stress conditions. Because the seasonal and daily dynamics of physiological and biochemical traits of maquis species are not fully addressed, we performed a field study on three coexisting Mediterranean shrubs (Pistacia lentiscus L. and Phillyrea latifolia L., evergreen schlerophylls, and Cistus incanus L., semi-deciduous) aiming at detecting the main adaptive differences, on a seasonal and daily basis, in primary and secondary metabolism along with the principal climatic determinants. These species differed in their physiological and biochemical responses especially on a seasonal level. In P. latifolia, a great investment in antioxidant phenylpropanoids contributed to maintain high photosynthetic rates throughout the whole growing season. In C. incanus, high carotenoid content associated with chlorophyll (Chl) regulation alleviated oxidative damage during the hot and dry summers and help recover photosynthesis in autumn. In P. lentiscus, high abscisic acid levels allowed a strict control of stomata, while fine Chla/Chlb regulation concurred to avoid photoinhibition in summer. Temperature resulted the most important climatic factor controlling the physiological and biochemical status of these coexisting shrubs and, thus, in determining plant performances in this Mediterranean coastal habitat.

Ecological and histopathological aspects of Didymodiclinus sp. (Trematoda: Didymozoidae) parasite of the dusky grouper, Epinephelus marginatus (Osteichthyes: Serranidae), from the western Mediterranean Sea.

The dusky grouper Epinephelus marginatus (Lowe) is an ecologically and commercially important fish species of the Atlantic and Mediterranean coastal rocky habitats. Despite records of didymozoid infections in several grouper species, the identification and pathogenesis of these parasites in E.marginatus are lacking. The aim of this study is to characterize the didymozoids of E.marginatus, particularly their mechanisms of infection and histopathological features. Dusky groupers (n=205) were caught off Majorca Island (western Mediterranean Sea) and examined for parasites. Of the fish sampled, 45% were infected with white and yellow didymozoid capsules and brown nodules, found on the gills and pseudobranchs. Parasite abundance had a strong positive relationship with the fish length; only fish larger than 20cm were infected, suggesting infection via consumption of an intermediate host, for which E.marginatus size was a limiting factor. The capsules contained two convoluted viable adult trematodes, identified as Didymodiclinus sp., in close contact with host capillary vessels, with no evidence of the tissue inflammatory response. Conversely, nodules containing degraded parasites were surrounded by an intense inflammatory infiltrate. The findings suggest that Didymodiclinus sp. have the potential to evade the host's immune system by inhibiting the inflammatory response.

Focal plant species and soil factors in Mediterranean coastal dunes: An undisclosed liaison?

Understanding the response of plant species to soil factors on coastal sand dunes is critical for effective conservation of coastal habitats in the Mediterranean basin. Our main objectives were to investigate: i) the main soil factors driving species composition in a Mediterranean coastal dune environment; ii) the ecological requirements of focal plant species with respect to single soil factors; iii) whether the focal species of a given macrohabitat (including EU habitats) have similar edaphic needs. We identified 108 plots with three macrohabitats as strata (embryo dunes; mobile dunes; fixed dunes) by random stratified sampling design along the Tyrrhenian coast of central Italy in areas with a high degree of biodiversity and naturalness. Vegetation and soil data were collected in the plots.Canonical Correspondence Analysis (CCA) confirmed that soil had a main role in driving focal dune species composition as found in other Mediterranean areas and indicated that three factors (field capacity, pH and CaCO3) sufficiently explain patterns of plant species. An inverse relation between field capacity, which proves to be the most decisive feature for differences in species ecological requirements between macrohabitats, and pH was observed. Generalized Additive Models (GAMs) showed that: i) the focal species of fixed dunes have a higher probability of occurrence and response curves that overlap at high field capacity and TOC values and at low pH, showing an opposite trend with respect to the species of embryonic and mixed dunes; ii) species of mixed dunes have a probability of occurrence linked to different values of CaCO3, with Ammophila arenaria showing its optimum at high CaCO3 values. Thus our results sustain the hypothesis that dune focal species, diagnostic and characteristic of coastal dune macrohabitats, have different ecological responses with respect to soil factors. Moreover, species within the same habitat can have different ecological responses due to species competition. Data about edaphic requirements of sand dune species and modelling of their ecological responses suggests that focal dune species can be bio-indicators of soil conditions and provide useful indications for conservation, monitoring and restoration of Mediterranean coastal habitats.

The effects of landscape history and time-lags on plant invasion in Mediterranean coastal habitats

Human-driven landscape changes may promote plant invasions by increasing propagule pressure and providing favourable conditions for non-native species to establish and spread. The increase in invasion levels might not be immediate but rather exhibit a time-lag (i.e. invasion debt). Moreover, the relationship between invasion and landscape history (i.e. changes in landscape composition) might be extremely complex as it might also include extinction debts of invasive species currently in regression. In order to understand the effect of landscape history on plant invasion, we studied the invasion level in coastal plant communities affected by intense human-driven landscape alteration in the last 50 years. We identified all non-native plant species within 809 grid cells (250 × 250 m) along ~500 km of the Spanish SW coast. We tested the association of (1) non-native richness conditional on the overall presence of non-natives (at least one species), and (2) the occurrence of the most frequent non-native species, with the percentage of human land-cover categories in 1956, 1991 and 2007 using a multimodel inference approach. We used these models to project future invasion patterns in the region. We found non-native richness to be more associated with land-cover variables in 1956 than in 2007, suggesting the existence of an invasion debt, but not for the overall presence of non-natives. For most frequent species, the effects of past landscape alteration depended on the introduction pathway and the region of origin. Species used in agriculture were more related to past cropland area, while most of the species used in gardening or forestry showed higher affinity for recently altered areas. These results highlight the relevance of the species’ introduction history and landscape history in assessing future long-term invasion trends.

The importance of the Cisto‐Lavanduletalia coastal habitat on population persistence of the narrow endemic Dianthus morisianus (Caryophyllaceae)

AbstractIn Mediterranean coastal dune habitats, the facilitative mechanisms among plants could be crucial for the persistence of several plants for which survival is linked to a fragile equilibrium with the surrounding microenvironment. The aim of this study was to verify whether there exists a facilitative effect on Dianthus morisianus Vals., a narrow endemic plant of Sardinia, and to analyze the potential importance of facilitative effects via the analysis of the interaction outcome with the nurse plants. Forty‐five plots of 1 × 1 m were randomly placed within the habitat where D . morisianus grows preferentially, composed of sclerophyllous shrubs (Cisto‐Lavanduletalia sensu Habitats Directive). All D . morisianus plants recorded within the plots were assigned to one of the three microhabitats identified: (i) open areas in the inter‐shrub discontinuities, (ii) under shrubs canopy influence and (iii) inside the shrubs. For each D . morisianus plant, the reproductive or vegetative status and both morphological and reproductive traits, as well as the possible physical damage (grazing and trampling), were measured. Inside the Cisto‐Lavanduletalia habitat there was a greater number of reproductive plants, whereas in the open patches the vegetative plants prevailed. Morphological and reproductive parameters varied significantly among microhabitats and showed higher values inside the shrubs. As expected, grazing and trampling negatively affected mainly plants growing in the open and below microhabitats. A strong facilitative interaction between D . morisianus and the coastal Cisto ‐ Lavanduletalia habitat was found: this habitat had a crucial positive effect on the persistence of D . morisianus and preserved this threatened plant; therefore, it is essential to primarily conserve the Cisto‐Lavanduletalia habitat.

Examining the role of landscape structure and dynamics in alien plant invasion from urban Mediterranean coastal habitats

This paper aims to disentangle the effects of both current landscape structure and recent land use-change on alien plant invasion in urban Mediterranean coastal habitats. Patches of four habitat types (rock outcrops, sand dunes, scrublands and forests) of different sizes and surrounding landscape compositions were selected along the coast of the Metropolitan Region of Barcelona (NE Spain). Attributes of habitat patches, historical (1956) and current landscape composition around them, land-cover changes (1956–2005) and other environmental and geographic factors within these patches were obtained. The association of these attributes with alien plant richness, abundance and composition was investigated using GLM and CCA. Alien species richness was mostly explained by patch size and shape and built-up area proportion from 1956 and 2005 in a 50m buffer around patches. Alien species abundance was mostly related to patch shape, temperature, rainfall, land-cover changes within patches and cropland cover of 1956 in a 50m buffer around patches. Alien species composition was primary related to habitat type, temperature, land-cover changes within patches and the composition of the surrounding landscape. Results suggest that landscape factors affect alien species richness and abundance differently, which are indicative of species colonization and spread, respectively. Landscape history positively affects both colonization and spread, with evidence for a colonization credit related with past urban cover, and the association between recent patch dynamics and present aliens spread. Results highlight the importance of including landscape structure and dynamics in the management of plant invasions in coastal Mediterranean habitats, especially in metropolitan regions.

Effects of reserve protection level on the vulnerable fish species Sciaena umbra and implications for fishing management and policy

The brown meagre Sciaena umbra, an iconic demersal fish species in Mediterranean coastal habitats, is particularly vulnerable to fishing pressure and presents a worrying population decline. Fish numbers and sizes were surveyed by visual census at Scandola (Corsica) in and outside reserve zones subject to increasing levels of protection, including unprotected zones (UP) where all fishing activities are permitted, buffer zones (BZ) subject to partial protection and a totally protected no-take integral reserve zone (IR). The numerical abundance, individual size and biomass of the brown meagre were found to increase with levels of reserve protection. The abundance of the larger size classes and the numbers of fish per shoal were significantly lower in unprotected zones. A comparison with similar censuses performed in 1983 showed a significant increase of S. umbra abundance in IR, but no difference in UP. That increasing levels of protection resulted in increased abundance and biomass of the brown meagre suggested a prominent role of fishing, particularly spearfishing, activities in the persistence of its low abundance in the unprotected zones. As a consequence, protective action for the brown meagre (including a ban on both spearfishing and recreational hook-and-line fishing) has been introduced in France since January 2014.