Mediterranean Ecoregion Research Articles

Trends in Vegetation Seasonality in the Iberian Peninsula: Spatiotemporal Analysis Using AVHRR-NDVI Data (1982–2023)

Vegetation seasonality is a critical indicator of ecological responses to global climate change, especially in the Iberian Peninsula, where the intersection of human activity and climate variability amplifies these effects. Understanding these changes is vital for adopting ecogeographical sustainability and developing effective climate adaptation strategies. This study examines trends in vegetation seasonality in the Iberian Peninsula from 1982 to 2023, based on weekly AVHRR NDVI data (2184 images). By integrating Seasonal Trend Analysis (STA) with Robust Trend Analysis (RTA)—including the Theil–Sen (TS) slope estimator, the Contextual Mann–Kendall (CMK) test (α = 0.05), and false discovery rate (FDR) control—we identified significant phenological shifts and widespread vegetation greening. The results reveal a regional response to global patterns of climate change, with 94.2% of the study area exhibiting significant trends, particularly in the Mediterranean ecoregion, where earlier growing seasons are becoming increasingly common. These shifts highlight the urgent need for sustainable land and resource management in the face of accelerating global change. Our findings provide critical insights into the ecological dynamics of the Iberian Peninsula, offering a robust foundation for formulating policies that promote environmental sustainability and enhance resilience to climate change.

A GIS-MCDA approach to map environmental suitability of Posidonia oceanica meadows as blue nature-based solutions in the Mediterranean eco-region

The growing environmental risks induced by interacting climate and human-induced pressures threaten the survival and growth of marine coastal ecosystems (MCEs) and the ecosystem services they provide. Nature-based solutions (NBS), consisting of ecosystem-based approaches, have emerged as vital tools for climate adaptation and mitigation facing biodiversity loss and societal challenges. Identifying suitable environmental conditions for implementing Blue-NBS in marine coastal areas is a key priority to drive robust and cost-effective nature-based adaptation pathways. This study developed a suitability model for Blue-NBS, with a specific focus on Posidonia oceanica meadows in the Mediterranean Sea under a baseline scenario. GIS-based Multiple Criteria Decision Analysis (MCDA) was applied for data integration and prioritization of different environmental variables in geomorphological (e.g., depth), water quality (WQ) (e.g., salinity), and climatic (e.g., thermal stress) sub-groups. Suitability classes and scores for each variable were determined using statistical distributions, ensuring a data-driven approach to defining environmental suitability. Variables' weights were derived from the Analytic Hierarchy Process (AHP) based on expert judgment and then combined with scores to generate suitability maps for managing Blue-NBS on seagrasses. Depth was found to be the most dominant environmental variable, with shallow areas (e.g., Northern Adriatic, Gulf of Gabés) showing higher suitability. The southern part of the Mediterranean (e.g., Egypt) reported relatively low scores for both climate and WQ, while the Northern Adriatic had the lowest WQ scores. This study represents the first attempt to evaluate Blue-NBS suitability for seagrass meadows at the eco-regional scale with geomorphologic, WQ, and climatic variables, providing decision support for the selection and allocation of Blue-NBS in different environmental settings. The resulting environmental suitability maps represent a basis for the integration of socio-economic and governance-related indicators into a more complex, multi-tier approach to support NBS mainstreaming.

Assessing citizen science data quality for bird monitoring in the Iberian Peninsula

Citizen science data on biodiversity has experienced significant growth, largely driven by advancements in technology that facilitate data sharing. In recent years, mobile applications have provided a substantial boost to both the collection and sharing of this data. While this accessible information is undoubtedly valuable, we must consider the numerous biases present in this data when used for high-quality research. In this study, we analyse citizen science data for the birds of the Iberian Peninsula, comprising over 23 million unique records after filtering for duplicates (i.e., instances where the same observation was uploaded more than once). Using a 10 × 10 km square grid, we present information on well-surveyed cells (completeness) as well as temporal, taxonomic, geographical, and land use coverages. We found that the completeness of information is generally high, with better coverage around densely populated areas such as major cities and coastal regions, as well as popular birding destinations, which are frequently visited. The Mediterranean ecoregion and wetlands exhibit the highest levels of surveying. Furthermore, we observed an increase in temporal coverage since the 1980s and broad taxonomic coverage across all bird orders in the Iberian region. Our results underscore the utility of citizen science for many locations, as expressed in 10 × 10 km cells. However, they also highlight the inadequate data completeness across part of the territory, particularly in forested or sparsely inhabited areas. These findings not only identify cells suitable for bird diversity or conservation studies but also indicate areas where citizen-driven bird recording efforts should be encouraged.

Climate change can disproportionately reduce habitats of stream fishes with restricted ranges in southern South America

Freshwater fishes are among the most threatened taxa worldwide owing to changes in land use, species introductions, and climate change. Although more than half of the freshwater fishes in the Chilean Mediterranean ecoregion are considered vulnerable or endangered, still little is known about their biogeography. Fishes of the family Perciliidae are endemic of this region and ideal cases to study potential implications of global warming given their endangered conservation status, small size, restricted range, and limited dispersal capacity in fragmented habitats. Here, we model the spatial distribution of habitats for Percilia irwini and P. gillissi under current (1970–2000) and future (2050–2080) climatic scenarios (SSP245, SSP585). We implement maximum entropy (MaxEnt) models adapted for stream networks using high-resolution datasets of selected geophysical and climatic variables. At present, both species inhabit relatively low-quality habitats. In the future (SSP585), suitable habitats for P. irwini are predicted to be reduced drastically (99%) with potential local extirpations in its northern range. Similarly, up to 62% of suitable habitats for P. gillissi would also be reduced in the future. Our study provides insights about assessing future threats and vulnerability of endemic, endangered, range-restricted, and small-bodied freshwater species in this region and elsewhere.

Regional uniqueness of tree species composition and response to forest loss and climate change

The conservation and restoration of forest ecosystems require detailed knowledge of the native plant compositions. Here, we map global forest tree composition and assess the impacts of historical forest cover loss and climate change on trees. The global occupancy of 10,590 tree species reveals complex taxonomic and phylogenetic gradients determining a local signature of tree lineage assembly. Species occupancy analyses indicate that historical forest loss has significantly restricted the potential suitable range of tree species in all forest biomes. Nevertheless, tropical moist and boreal forest biomes display the lowest level of range restriction and harbor extremely large ranged tree species, albeit with a stark contrast in richness and composition. Climate change simulations indicate that forest biomes are projected to differ in their response to climate change, with the highest predicted species loss in tropical dry and Mediterranean ecoregions. Our findings highlight the need for preserving the remaining large forest biomes while regenerating degraded forests in a way that provides resilience against climate change.

Extreme drought triggers parallel shifts in wood anatomical and physiological traits in upper treeline of the Mediterranean Andes

BackgroundTreeline ecotones of Mediterranean ecoregions have been affected by the increasing intensity and severity of droughts. Even though the effect of droughts on forest dynamics has been widely documented, knowledge is relatively scarce of how extreme climate episodes affect the hydraulic structure and, therefore, the physiology of woody plants. The Mediterranean Andes have experienced an uninterrupted period of drought since 2010, including an extremely dry year in 2019 with approximately 80% rainfall deficit. Here, we investigated shifts in wood anatomical and physiological traits of Kageneckia angustifolia, an endemic treeline species, in response to this drought period.MethodsWe evaluated the xylem plasticity of three K. angustifolia populations across their natural distribution (31–35° SL) based on anatomical (vessel structure and distribution) and physiological (intrinsic water-use efficiency) variables in the tree rings. We focused on the period 2000–2020 that corresponds to before the megadrought (2000–2007), (ii) megadrought (2008–2018) and (iii) hyperdrought (2019–2020). The variables were annualized and analyzed by linear mixed-effects models.ResultsOur results provide insights to the anatomical and physiological mechanisms underlying the resilience of treeline forests to persistent droughts in central Chile. We found that the extreme drought in 2019–2020 triggered shifts in vessel size and frequency that increased hydraulic safety. These significant shifts in vessel traits occurred in parallel with a decrease in pit aperture area and an increase in water-use efficiency, further increasing the resilience of K. angustifolia to extreme drought stress.ConclusionsOur results revealed coordinated shifts in vessel size and frequency and water-use efficiency in response to the megadrought, thereby reducing vulnerability to hydraulic failure. The apparent resilience of K. angustifolia to extreme droughts suggests that this adaptation to drought stress may increase its ability to tolerate novel climatic conditions of treeline environments of the Mediterranean Andes, although it is not clear whether these adaptations will be sufficient to persist in scenarios that predict intensification of climate stress. Finally, our results provide empirical evidence that integrating wood anatomical and physiological traits facilitates the understanding of resilience mechanisms that treeline forests develop in the face of increasing drought stress.

Carbon sequestration in the Mediterranean Ecoregion forests in Türkiye towards macro-scale planning

Üst ölçekli planlama kapsamında orman ekosistemlerinde karbon tutumunun hesaplanması ve değerlendirilmesi, ormancılık faaliyetlerinin sürdürülmesi ve izlenmesi açısından önemlidir. Sürdürülebilir ve karbon odaklı ormancılık faaliyetleri karbon tutumunun düşük olduğu alanlarda, doğal ekosistem yapısına zarar vermeden karbon tutumunu artırmakta ve sera gazlarının azaltımına ilave katkı sağlamaktadır. Bu çalışmada Türkiye’nin Akdeniz Ekolojik Bölgesi’ndeki ormanlar için mevcut karbon tutumu, meşcere hacim değerleri ve uluslararası kabul görmüş katsayılar kullanılarak hesaplanmış ve haritalandırılmıştır. Çalışmada (1) orman idari sınırları için yapraklı ve ibreli ağaç türlerinin hektardaki ortalama karbon stok değerleri, (2) tüm bölgedeki yapraklı (saf ya da yapraklı ağaç türü ağırlıklı) ve ibreli (saf ya da ibreli ağaç türü ağırlıklı) meşcereler için hektardaki ortalama karbon stok değerleri, (3) kızılçam [Turkish red pine (Pinus brutia Ten.)] ve karaçam [black pine (P. nigra Arnold)] için çağ ve kapalılığa göre hektardaki ortalama biyokütle karbon stok değerleri hesaplanmıştır. Orman İşletme Şefliklerindeki orman meşcere türlerine göre ortalama toprak üstü biyokütle karbon stoku normal kapalı ibreli meşcereler için 36,12 ton C/ha ve normal kapalı yapraklı meşcereler için 20,13 ton C/ha’dır. Kızılçam için Çzde3 ve Çze3 meşcereleri ve karaçam için Çkde3 ve Çke3 meşcereleri en yüksek karbon tutumunu sağlamaktadır. Bu çalışmanın sonuçları, ekosistemlerin doğal yapısının da gözetilerek karbon stoku (depolaması) açısından ağaç türü seçiminde ve silvikültürel uygulamaların belirlenmesinde kullanılabilecektir. Bunun dışında meşcerede baskın olmayan türlerin karbon stok potansiyeli ilk kez bu çalışmada değerlendirilmiştir. Bu bilgi, bu türlerin karışımlarda korunmasını destekleyecektir. Son olarak, karbon yönetiminde yutak alanların ve karbon tutumunun artırılmasına yönelik çalışmaların artırılması ve önlemlerin alınması ya da sorunlara müdahale edilmesi gibi faaliyetlerde şeflikler arasındaki meşcere karbon stok farklarının gözetilmesini de sağlayacaktır.

Gone with the stream: Functional connectivity of a cold‐water coral at basin scale

AbstractLophelia pertusa reefs are vulnerable deep‐sea ecosystems and their ecological integrity partly depends on the connectivity and availability of suitable habitat. Moreover, connectivity is a guiding principle in marine conservation planning, particularly for spatial prioritization and for the design of networks of marine protected areas. We estimated the functional seascape connectivity of L. pertusa in the Mediterranean Sea and provide a framework for prioritizing habitat areas for the species conservation. These goals were achieved by simulating transport and potential dispersal of virtual larvae using biophysical modeling and assessing habitat availability based on the suitability and spatial arrangement of the seascape and inter‐annual climatological variability. Habitat availability was estimated using a network analysis and accounting for the attributes of habitat areas (i.e., size and quality). The connectivity among Mediterranean ecoregions was weak and an increase in the frequency of climate‐driven events (e.g., dense shelf water cascading) may worsen this scenario. However, the potential exchange of larvae between patches within the same ecoregion was high, favoring populations resilience to local disturbances. The analysis of habitat availability allowed identifying important habitat areas for the connectivity of the L. pertusa including the Gulf of Lion, the Apulian and Sicily Island continental margin. Some of the habitat areas identified as important for the connectivity of the L. pertusa are exposed to intense anthropogenic pressures, that may act synergistically with climate change imposing greater challenges to species conservation. These habitat areas may be prioritized in future management and conservation actions targeting L. pertusa.

Genomic data resolve phylogenetic relationships of Australian mat-rushes, Lomandra (Asparagaceae: Lomandroideae)

Abstract Lomandra is the largest genus in Asparagaceae subfamily Lomandroideae and possesses economic, ecological, and ethnobotanical significance in Australia. Lomandra comprises four sections, L. section Capitatae, L. section Macrostachya, L. section Typhopsis and L. section Lomandra, the latter comprising series Lomandra and series Sparsiflorae, all recognized based solely on morphology. In this study, phylogenetic relationships were estimated for 79 Lomandroideae individuals, including 45 Lomandra species and subspecies (c. 63% of species and subspecies diversity). We generated genome-scale plastome sequence data and used maximum likelihood and Bayesian inference criteria for phylogenetic estimation. Lomandra was non-monophyletic, with Xerolirion divaricata nested within it. Two major clades were recovered: Capitatae–Macrostachya (CM) and Lomandra–Typhopsis (LT). The CM clade included a monophyletic Lomandra section Capitatae with a base chromosome number x = 7, and L. section Macrostachya (x = 8); the LT clade included L. sections Typhopsis and Lomandra, both x = 8. Section Lomandra series Lomandra and series Sparsiflorae were both recovered as non-monophyletic. Morphological characters were assessed to identify combinations of characters that characterize clades. A base chromosome number of x = 8 was plesiomorphic for Lomandra. The largest number of Lomandra species occupy the Mediterranean ecoregion and occupancy of sclerophyll vegetation was reconstructed as ancestral for the genus.

Prolonged Drought in a Northern California Coastal Region Suppresses Wildfire Impacts on Hydrology

AbstractWildfires naturally occur in many landscapes, however they are undergoing rapid regime shifts. Despite the emphasis in the literature on the most severe hydrological responses to wildfire, there remains a knowledge gap on the thresholds of wildfire (i.e., burned area/drainage area ratio, BAR) required to initiate hydrological responses. We investigated hydrological changes in the Russian River Watershed (RRW) in California, a coastal, Mediterranean, drought‐prone, wildfire‐adapted ecosystem, following ten wildfires that burned 30% of the watershed. Our findings suggest that sub‐watersheds of the RRW have not burned beyond an intrinsic, unknown, threshold required to initiate change. Using paired watersheds, we examined spatiotemporal patterns of pre‐and‐post wildfire hydrology with a rainfall‐runoff hydrological model. Even though these successive wildfires burned 1%–50% of each sub‐watershed (1%–30% at moderate/high severity), we found little evidence of wildfire‐related shifts in hydrology. As a function of BAR, wildfire imposed limited effects on runoff ratios (runoff/precipitation) and runoff residuals (observations—model simulations). Our findings that post‐wildfire runoff enhancements asymptote beyond 30% burn indicate that when a watershed is burned beyond a certain threshold, the magnitude of the hydrologic response no longer increases. Drought and storm conditions explained much of the variability observed in streamflow, whereas wildfire explained only moderate variability in streamflow even when wildfire accounted for >45% BAR. While the BAR in the RRW was sufficiently beyond previously reported minimum disturbance thresholds (>20% burned forest), the lack of hydrological response is attributed to buffering effects of wildfire adaptation and drought factors that are unique to Mediterranean ecoregions.

Microhabitat partitioning between sympatric intertidal fish species highlights the importance of sediment composition in gravel beach conservation.

Gravel beaches in the Mediterranean ecoregion represent an economically important and unique habitat type. Yet, burgeoning tourism, intensive coastal development and artificial nourishment of beaches may jeopardize their ecological communities. To date, species that reside on gravel beaches and the consequences of beach alterations are poorly understood, which hampers the development of a sustainable coastal tourism industry along the region's shorelines. Using a simple collection method based on dredging buckets through the intertidal section of beaches, we quantified the microhabitat association of two sympatric clingfish species in the genus Gouania at seven natural and an artificial gravel beach based on sediment characteristics. We hypothesized that slender (G. pigra) and stout (G. adriatica) morphotypes would partition interstitial niche space based on sediment size, which may affect the vulnerability of the species to changes in gravel beach composition due to coastal development. We detected substantial differences in gravel composition within and among the sampled beaches which suggests scope for microhabitat partitioning in Gouania. Indeed, we found significant relationships between species identity and the presence/absence and abundance of individuals in hauls based on their positioning on PC1. Our results suggest that modifications of gravel beaches through coastal development, including beach nourishment, intensifying coastal erosion, or artificial beach creation, may have detrimental consequences for the two species if sediment types or sizes are altered. We posit that, given the simplicity and efficacy of our sampling method and the sensitivity of Gouania species to prevailing gravel composition, the genus could serve as an important indicator for gravel beach management in the Mediterranean ecoregion.

The European freshwater landscape and hotspot areas of mass effects and regional connectivity

AbstractAimThe maintenance of broad‐scale connectivity patterns is suggested as a sustainable strategy for biodiversity preservation. However, explicit approaches for quantifying the functional role of different areas in biogeographic connectivity have been elusive. Freshwaters are spatially structured ecosystems critically endangered because of human activities and global change, demanding connectivity‐based approaches for their conservation. Mass effects—the increase in local diversity by immigration—and corridor effects—the connections with distant communities—are basic and relevant mechanisms connecting diversity with landscape configuration. Here, we identified freshwater hotspots areas for mass and corridor effects across Europe.LocationEurope.MethodsUsing satellite images, we quantified the areas of ephemeral, temporal and permanent freshwaters. The landscape structure of the freshwater ecoregions was represented as a directed‐graph, and the link weights were determined by the distance between cells and the water cover. Three centrality metrics were used to rank freshwater areas with respect to their potential role in dispersal‐mediated mechanisms. Out‐degree represents the potential of an area to operate as a diversity source to other regions. In‐degree reflects the importance that incoming dispersal may have in local diversity. Betweenness refers to the importance of local areas for connecting other distant areas.ResultsWe detected great concentrations of source hotspots on the northern regions associated to lentic ecosystems, main European rivers acting as ecological corridors for all freshwaters, and a mixed distribution of connectivity hotspots in southern and Mediterranean ecoregions, associated with lentic and/or lotic systems.Main ConclusionsWe showed an explicit connection between landscape structure and dispersal process at large geographic scales, highlighting hotspots of connectivity for the European waterscape. The spatial distribution of hotspots points to differences in landscape configurations potentially accounting for biogeographic diversity patterns and for mechanisms that have to be considered in conservation planning.

Phytoplankton Size Structure and Diversity in the Transitional System of the Aquatina Lagoon (Southern Adriatic Sea, Mediterranean).

The Aquatina Lagoon (Southern Adriatic Sea, Mediterranean Ecoregion) is a transitional water ecosystem with great ecological and socio-economic interest. Anthropogenic activities around the lagoon (e.g., agriculture and tourism) and hydrology can affect the environmental quality and biodiversity of the lagoon. Herein, the dynamics and diversity of phytoplankton communities were studied before and after the opening of a new canal connecting the lagoon with the sea, by using different approaches based on an evaluation of the size and structure of the phytoplankton as well as the taxonomic analyses. The lagoon depicted time-related fluctuations in chemical-physical parameters. The phytoplankton trend was characterized by an increase in abundance and biomass in summer, when pico-sized autotrophs dominated. Generally, nano-sized phytoflagellates dominated the community, while micro-sized dinoflagellates and diatoms were less abundant. An increase in the phytoplankton taxa number was observed throughout the years. All the analyzed parameters were generally relatively homogeneous before the opening of the channel, while some quantitative differences among stations were observed in the second sampling period. Considering the statistical evidence, both environmental and biological parameters were affected by the "dilution" effect exerted by marine water inputs. This research supports the evidence that phytoplankton is a good indicator of the environmental status, and the obtained results contribute to the implementation of management strategies for the conservation of transitional water ecosystems.

Macroinvertebrate assemblages downstream of dams show no sign of impairment despite flow regulation and thermal alteration

Flow regulation by dams produced downstream effects, including geomorphological, hydrological and thermal alterations. We aimed to analyse the alterations of the thermal regime caused by hypolimnetic releases of regulated flow compared to the unregulated thermal regime, and the effects of both thermal and flow regime alterations on macroinvertebrate communities. Stream temperature was monitored over three-years in three rivers with contrasting flow regimes, all located in the Mediterranean ecoregion. Results show that regulated rivers present an inverted flow regime with high discharges in summer, colder water from February to September arising maximum differences of 7.4 °C in July and presenting a delayed thermal maximum of 2 to 2.5 months compared with the unregulated river. Given the relevant hydrological and thermal alterations found in both regulated rivers, unexpectedly no differences were found between regulated and unregulated rivers when analysing macroinvertebrate richness and diversity indexes. The taxonomic response is significantly different among the three rivers in summer and was mostly explained by summer indicators, with the maximum water temperature of July being present in all models. An indirect driver that exacerbates the thermal differences found between regulated and unregulated rivers would be the geomorphological configuration of the rivers reciprocally interacting with the riparian vegetation. The monitoring of stream temperature is a crucial activity needed to implement since this parameter together with water flow shapes the distribution of aquatic biota in river ecosystems.

Macroinvertebrate-Based Biomonitoring of Coastal Wetlands in Mediterranean Chile: Testing Potential Metrics Able to Detect Anthropogenic Impacts

Coastal wetlands are suffering from anthropogenic alterations worldwide. Aquatic monitoring based on macroinvertebrates has been successfully used to assess the ecological condition of many aquatic systems worldwide. Nonetheless, studies are still insufficient for the coastal wetlands of the South Pacific. Here, we present a preliminary attempt to select metrics based on aquatic macroinvertebrates to incorporate into coastal wetlands biomonitoring in the Chilean Mediterranean ecoregion. We sampled 25 sites in ten coastal wetlands during the austral spring of 2019. We used an integrated index that considers both human activities at catchment and at local scales to identify sites less or more disturbed. We tested a total of 70 metrics (either traditional or new metrics) representing different aspects of community structure/composition, functions and tolerance to pollution. Two metrics were finally retained: detritivore abundance (traditional metric) and geometric mean body size (new metric). These metrics were able to detect sites impacted by human activities. Thus, they might be considered as candidate metrics for the biomonitoring of these systems and to develop future indices. Moreover, because of their generality, they might also be applicable to coastal wetlands in other Mediterranean regions, including sites where taxonomic identification is still a challenge.

DNA Barcode Gap Analysis for Multiple Marker Genes for Phytoplankton Species Biodiversity in Mediterranean Aquatic Ecosystems

Simple SummaryEnvironmental DNA metabarcoding (eDNA) has strong potential in the assessment of biodiversity in aquatic ecosystems. The incompleteness of DNA barcode reference libraries represents a current limit to unveiling the whole biodiversity of an aquatic ecosystem. Therefore, barcode gap analyses at species level are of great significance, in particular at local/regional level, for the advancement of eDNA metabarcoding application to aquatic ecosystems surveillance and future biodiversity assessment.The implementation of DNA metabarcoding and environmental DNA (eDNA) to the biodiversity assessment and biomonitoring of aquatic ecosystems has great potential worldwide. However, DNA metabarcoding and eDNA are highly reliant on the coverage of the DNA barcode reference libraries that are currently hindered by the substantial lack of reference sequences. The main objective of this study was to analyze the current coverage of DNA barcode reference libraries for phytoplankton species of the aquatic Mediterranean ecoregion in the southeast of Italy (Apulia Region) in order to assess the applicability of DNA metabarcoding and eDNA in this area. To do so, we investigated three main DNA barcode reference libraries, BOLD Systems, GenBank and SILVA, for the availability of DNA barcodes of the examined phytoplankton species. The gap analysis was conducted for three molecular gene markers, 18S, 16S and COI. The results showed a considerable lack of barcodes for all three markers. However, among the three markers, 18S had a greater coverage in the reference libraries. For the 18S gene marker, the barcode coverage gap across the three types of ecosystems examined was 32.21–39.68%, 60.12–65.19% for the 16S marker gene, and 72.44–80.61 for the COI marker gene. Afterwards, the interspecific genetic distance examined on the most represented molecular marker, 18S, was able to distinguish 80% of the species mined for lakes and 70% for both marine and transitional waters. Conclusively, this work highlights the importance of filling the gaps in the reference libraries, and constitutes the basis towards the advancement of DNA metabarcoding and eDNA application for biodiversity assessment and biomonitoring.

Sclerophyllous Forest Tree Growth Under the Influence of a Historic Megadrought in the Mediterranean Ecoregion of Chile

Sclerophyllous Forest Tree Growth Under the Influence of a Historic Megadrought in the Mediterranean Ecoregion of Chile

Optimizing Carbon Sequestration Through Cover Cropping in Mediterranean Agroecosystems: Synthesis of Mechanisms and Implications for Management

Hot and dry Mediterranean ecoregions are characterized by low soil organic carbon content and large potential to become carbon sink when appropriately managed. Soil carbon sequestration may also play an important role in improving the resilience of these vulnerable agroecosystems to increasingly drastic impacts of global climate change. One agricultural practice that aims to increase soil organic carbon stocks, among other beneficial outcomes, is the use of cover crops. Although cover crops can increase soil organic carbon content, recent studies have observed that cover crops may lead to lower soil carbon stocks when considering co-management strategies, especially at greater soil depths. In this review, we outline the current paradigm of soil organic carbon dynamics and aim to apply our current understanding of soil carbon sequestration processes to cover crop management. We review how cover crop practices such as cover crop species selection, growth duration, and termination methodologies may impact soil organic matter sequestration and stabilization processes and provide insights to direct future research and inform cover crop management for C sequestration in Mediterranean agroecosystems.

An integrated assessment of the Good Environmental Status of Mediterranean Marine Protected Areas

Local, regional and global targets have been set to halt marine biodiversity loss. Europe has set its own policy targets to achieve Good Environmental Status (GES) of marine ecosystems by implementing the Marine Strategy Framework Directive (MSFD) across member states. We combined an extensive dataset across five Mediterranean ecoregions including 26 Marine Protected Areas (MPAs), their reference unprotected areas, and a no-trawl case study. Our aim was to assess if MPAs reach GES, if their effects are local or can be detected at ecoregion level or up to a Mediterranean scale, and which are the ecosystem components driving GES achievement. This was undertaken by using the analytical tool NEAT (Nested Environmental status Assessment Tool), which allows an integrated assessment of the status of marine systems. We adopted an ecosystem approach by integrating data from several ecosystem components: the seagrass Posidonia oceanica, macroalgae, sea urchins and fish. Thresholds to define the GES were set by dedicated workshops and literature review.In the Western Mediterranean, most MPAs are in good/high status, with P. oceanica and fish driving this result within MPAs. However, GES is achieved only at a local level, and the Mediterranean Sea, as a whole, results in a moderate environmental status. Macroalgal forests are overall in bad condition, confirming their status at risk. The results are significantly affected by the assumption that discrete observations over small spatial scales are representative of the total extension investigated. This calls for large-scale, dedicated assessments to realistically detect environmental status changes under different conditions.Understanding MPAs effectiveness in reaching GES is crucial to assess their role as sentinel observatories of marine systems. MPAs and trawling bans can locally contribute to the attainment of GES and to the fulfillment of the MSFD objectives. Building confidence in setting thresholds between GES and non-GES, investing in long-term monitoring, increasing the spatial extent of sampling areas, rethinking and broadening the scope of complementary tools of protection (e.g., Natura 2000 Sites), are indicated as solutions to ameliorate the status of the basin.

West Coast vegetation shifts as a response to climate change over the past 130,000 years: geographic patterns and process from pollen data

ABSTRACT We compiled pollen sequences from lake and offshore cores at least 6,000 years old (6 ka) for the Mediterranean and Marine ecoregions of the US West Coast. Principal Component Analysis highlighted vegetation differences in core-tops, the Holocene Thermal Maximum (6 ka) and Last Glacial Maximum (LGM, 19 ka). Core-top and HTM ordination produced clusters that reflected geographic clusters in the Sierra Nevada, and the Pacific Northwest coast. Little change in these clusters between 6-0 ka suggested that vegetation communities in coastal and alpine settings persisted, despite warmer global temperatures. PCA outliers reflect distinct pollen assemblages that often were isolated sites or bordered the Great Basin. During the LGM, greater shrub and herb presence in the Marine ecoregion interior indicated enhanced aridity, while conifer presence in coastal and Southern California indicated moist conditions. Qualitatively, tree taxa from the Last Interglacial (~130–120 ka) showed how vegetation shifted over 6–10 kyr from alder, to oak, then redwood, a successional pattern that began again at the Late Glacial (~15 ka). In future West Coast pollen studies, sampling and chronologic control at centennial resolution will enable further study of more time periods and rates of vegetation change in response to climate.