The beaching events of holopelagic (free-floating) Sargassum, marked by the substantial influx of brown seaweed along the Atlantic coastlines, present a considerable challenge to marine ecosystems and coastal economies, as its clonal growth disrupts local biodiversity and affects industries including tourism and fisheries. The Sargassum fluitans and S. natans have been found for the first time along the Atlantic coast of Morocco, North Africa, between late March and early May 2024. The beached biomass consisted of the main morphotypes identified in the tropical Atlantic Ocean: S. fluitans var. fluitans (syn. S. fluitans III) and S. natans var. natans (syn. S. natans I) and S. natans var. wingei (syn. S. natans VIII). The in-situ observation of drifting Sargassum populations revealed a density of 10 +/- 3 fronds/m2 where S. natans var. wingei was the dominant form (58 %). Leading us think of the origin of their transport and stranding on the Atlantic Moroccan coasts that might have been caused by extreme climatic and hydrodynamic events that occurred after Nelson storm late March 2024. Major environmental drivers, including the Sea surface temperature (SST) variability, North Atlantic Oscillation (NAO) index and prevailing wind patterns were considered. This unusual event should prompt more monitoring and vigilance regarding the circulation of marine currents and species introduced into this region.

Ruppia drepanensis Tineo ex Guss. is an important habitat-forming aquatic plant in saline and brackish Mediterranean wetlands. The species is declining in several parts of its range due to hydrological changes and habitat degradation. R. drepanensis was considered Critically Endangered, possibly Regionally Extinct in Portugal, due to not being observed since 1986 despite extensive surveys of suitable habitat. We report on a new population, the westernmost known record for the species in Europe, identified with morphological and molecular data. Despite being inside a protected area, this population occupies a single small pond adjacent to a road, making it vulnerable to habitat changes. Ex situ conservation is recommended, including seed banking and/or the establishment of new populations.

Brown algal forests provide many ecosystem services but are declining worldwide, prompting a growing number of conservation and restoration efforts. Recent attempts to recover Cystoseira forests are encouraging in the Mediterranean, but whether this is possible in more challenging Atlantic conditions has not yet been investigated. In this study, we assess the feasibility of cultivating Gongolaria nodicaulis by producing ex-situ recruits for reforestation on the Atlantic coast of Morocco. Embryos of G. nodicaulis were cultured on clay tiles for 26 days under controlled conditions without water motion, reaching an average length of 3 mm before being outplanted on the intertidal zone. The transplants were monitored for six months. Recruits experienced high loss rates, approximately 47 % of zygotes within 7 days in culture and 75 % of outplanted seedlings within 10 days in the field. The latter might result from natural self-thinning (competition), but our observations suggested that it was also largely due to the weak attachment of recruits to the tiles resulting from cultivation under calm conditions. Six months after the transplants, the surviving individuals reached the size of wild adult algae (average length of 13.5 cm), and some even became reproductive. Globally, survival rates, growth, physiological condition and fertility in this restoration pilot suggest that ex-situ recruitment and outplanting of G. nodicaulis is a promising approach to recover forests in Atlantic Morocco.

Alien plant species are considered to be the second cause of global biodiversity loss after direct habitat destruction. In Algarve (Southern Portugal), invasive alien plants represent a major threat to biodiversity, not only in heavily transformed landscapes areas but also in natural habitats of high conservation value. A loss or decline of these ecosystems would affect priority habitats (from Natura 2000 network natural habitats) and threatened species, included in the Red List of vascular plants for mainland Portugal. In order to develop an adequate baseline to address the problems raised by invasive species, we present the first checklist of alien vascular flora in Algarve region (Southern Portugal), as a crucial baseline for further studies and regional action plans to implement and enforce more effective management strategies involving alien plants.

Amphiboreal taxa are often composed of vicariant phylogroups and species complexes whose divergence and phylogeographic affinities reflect a shared history of chronic isolation and episodic trans-Arctic dispersal. Ecological filters and shifting selective pressures may also promote selective sweeps, niche shifts and ecological speciation during colonization, but these are seldom considered at biogeographical scales. Here we integrate genetic data and Ecologic Niche Models (ENMs) to investigate the historical biogeography and cohesion of the polymorphic rockweed Fucus distichus throughout its immense amphiboreal range, focusing on trans-Arctic asymmetries, glacial/interglacial dynamics, and integrity of sympatric eco-morphotypes. Populations were sampled throughout the Pacific and the Atlantic, from southern rear-edges to the high-Arctic. They were genotyped for seven microsatellites and an mtDNA spacer, and genetic diversity and structure were assessed from global to local scales. ENMs were used to compare niche divergence and magnitude of post-glacial range shifts in Pacific versus Atlantic sub-ranges. Haplotypic and genotypic data revealed distinct and seemingly isolated Pacific vs Arctic/Atlantic gene-pools, with finer-scale regional sub-structuring pervasive in the Pacific. MtDNA diversity was highly structured and overwhelmingly concentrated in the Pacific. Regionally, Alaska showed the highest intra-population diversity but the lowest levels of endemism. Some sympatric/parapatric ecotypes exhibited distinct genotypic/haplotypic compositions. Strikingly, niche models revealed higher Pacific tolerance to maximum temperatures and predicted a much more consolidated presence in the NE Atlantic. Glacial and modern ranges overlapped extensively in the Pacific, whereas the modern Atlantic range was largely glaciated or emerged during the Last Glacial Maximum. Higher genetic and ecogeographic diversity supports a primary Pacific diversification and secondary Atlantic colonization, also likely reflecting the much larger and more stable climatic refugia in the Pacific. The relic distribution and reduced ecological/morphological plasticity in the NE Atlantic are hypothesized to reflect functional trans-Arctic bottlenecks, recent colonization or competition with congeners. Within the Pacific, Alaska showed signatures of a post-glacial melting pot of eastern and southern populations. Genetic/ecotypic variation was generally not sufficiently discontinuous or consistent to justify recognizing multiple taxonomic entities, but support a separate species in the eastern Pacific, at the southern rear-edge. We predict that layered patterns of phylogeographic structure, incipient speciation and niche differences might be common among widespread low-dispersal amphiboreal taxa.

Althenia (Potamogetonaceae) is a small genus of aquatic angiosperms from saline environments that includes the most recently evolved seagrass, Althenia marina. One or two species occur in Europe, both rare and considered Data Deficient at the regional level. We report the first records of Althenia in Portugal since 1853: two populations in the Algarve and a third in central Portugal. As in previous studies, all Portuguese populations include plants with and without visible nerves in the leaf sheaths, a character used to distinguish between A. orientalis and A. filiformis. We tentatively recognize a single Althenia species in Eurasia, pending further studies. We recommend further searches of suitable habitat, as Althenia species are small and easily overlooked, as well as monitoring and safeguarding of known populations through in situ and ex situ conservation.

Genotypic data (8 loci) of 35 populations of Ecklonia maxima and Ecklonia radiata from South Africa and Australia

The southern coast of Africa is one of the few places in the world where water temperatures are predicted to cool in the future. This endemism-rich coastline is home to two sister species of kelps of the genus Ecklonia maxima and Ecklonia radiata, each associated with specific thermal niches, and occuring primarily on opposite sides of the southern tip of Africa. Historical distribution records indicate that E. maxima has recently shifted its distribution ~ 70 km eastward, to sites where only E. radiata was previously reported. The contact of sister species with contrasting thermal affinities and the occurrence of mixed morphologies raised the hypothesis that hybridization might be occurring in this contact zone. Here we describe the genetic structure of the genus Ecklonia along the southern coast of Africa and investigate potential hybridization and cryptic diversity using a combination of nuclear microsatellites and mitochondrial markers. We found that both species have geographically discrete genetic clusters, consistent with expected phylogeographic breaks along this coastline. In addition, depth-isolated populations were found to harbor unique genetic diversity, including a third Ecklonia lineage. Mito-nuclear discordance and high genetic divergence in the contact zones suggest multiple hybridization events between Ecklonia species. Discordance between morphological and molecular identification suggests the potential influence of abiotic factors leading to convergent phenotypes in the contact zones. Our results highlight an example of cryptic diversity and hybridization driven by contact between two closely related keystone species with contrasting thermal affinities.

ABSTRACT The first record of the kelp species Phyllariopsis brevipes in the Campania Region (Tyrrhenian Sea, South Italy) is here reported. The species has been observed in October 2021 in four sites along Sorrento Peninsula and Capri Island coast during scuba diving surveys. P. brevipes grew on living thalli of crustose coralline algae from 32 up to 55 m depth, occasionally forming dense aggregations with a maximum cover of about 0.2 m 2 . The DNA barcoding analysis on the basis of the cox1 gene supported the identification, with 98.36% of similarity between the sample collected in this study (NCBI accession number: PP622796 ) and a sequence obtained from a specimen from Provence, Mediterranean France (NCBI accession number: GQ368264 ). The study area can be considered a stepping stone for the species dispersion. The occurrence of P. brevipes can be related to upwelling and good water quality and the monitoring of its health status might be a sentinel of environmental changes.

Cystoseira sensu lato (s.l.) - encompassing the genera Cystoseira sensu stricto (s.s.), Ericaria and Gongolaria - is a diverse group of forest-forming brown macroalgae endemic to the warm-temperate North-east Atlantic. These algae have immense biogeographic and ecological significance and have been experiencing recent regional declines. Most Cystoseira s.l. display important morphological plasticity and can be confused with similar species. Therefore, species boundaries, geographic ranges and phylogenetic affinities remain imprecise for most. In the face of persistent taxonomic difficulties, several authors underlined the necessity for new molecular-based approaches, but studies so far lacked representativity, resolution and standardization. To fill in these gaps, in this study we sequenced a comprehensive collection of Cystoseira s.l. spanning its entire North-east Atlantic range for a similar to 1200 bp cox1 barcode, and sequenced selected individuals representing major genetic entities for a few additional plastid markers. Phylogeographic, phylogenetic and species delimitation methods revealed 27 Molecular Operational Taxonomic Units, including unaccounted cryptic diversity, and elucidated with unprecedented resolution species compositions and phylogenetic relationships within each genus. Some entities within the lineages Cystoseira compressa/humilis, Ericaria brachycarpa/crinita, E selaginoides and tophulose Gongolaria, as well as among free-living algae, conflicted with a priori taxonomic assignments, and required the redefinition, reinstatement and recognition of new taxa. For some, diagnostic mutations and biogeography were more useful for species identifications than morphological characters or conventional barcoding gaps. A few species showed narrow geographic ranges and others were the sole representatives of their respective lineages. Several sister-species showed Atlantic vs Mediterranean complementary ranges. phylogenetic signal of coxl was nevertheless insufficient to confidently determine patterns of lineage splitting in several lineages and species complexes and did not improve significantly with additional plastid markers. We discuss novel systematics and biogeography insights considering the advantages and shortcomings of the barcoding approach employed, and how this comprehensive baseline study can be expanded to address multiple questions still left unanswered.

Fucales (Phaeophyceae) are ecosystem engineers and forest-forming macroalgae whose populations are declining dramatically. In the Mediterranean Sea, Cystoseira sensu lato (s.l.)-encompassing the genera Cystoseira sensu stricto, Ericaria, and Gongolaria-is the most diverse group, and many species have been shown to be locally extinct in many areas, resulting in a shift toward structurally less complex habitats with the consequent loss of ecosystem functions and services. In this study, we report on the extensive occurrence of healthy and dense marine forests formed by Fucales in the Santa Maria di Castellabate Marine Protected Area in Cilento, Italy (Tyrrhenian Sea, Mediterranean). On a total area of 129.45 ha, 10 Cystoseira s.l. taxa were detected using a combined morphological and molecular approach, with an average cover of more than 70%. One of these taxa has been sequenced for the first time. These findings underline the high ecological value of this area as a hotspot of benthic biodiversity and highlight the importance of marine protected area management and regional monitoring programs to ensure the conservation of these valuable yet fragile coastal ecosystems.

Microsatellite data (12 loci) of 14 populations of Laminaria digitata covering the entire species range

A large tract of mangrove forest in Malaysia has been lost due to increased anthropogenic activities. Restorative practices of mangrove forest have been adopted nationwide to re-establish ecosystem services in combating coastal erosion. However, genetic considerations in local mangrove restoration practices are still far lacking despite the vast literature on their genetic diversity. To understand whether the restored mangroves can impact the genetic diversity distribution among natural populations, we used eight microsatellite markers to assess the genetic diversity of the Api-api putih (Avicennia alba) between the natural and restored populations along the west coast of Peninsular Malaysia. We found no difference in terms of genetic diversity between these populations. Two genetic clusters were detected among A. alba along the west coast based on Bayesian clustering and discriminant analysis of principal components (DAPC). The southwest monsoon current circulation that coincides the timing of seed dispersal of A. alba may explain such pattern of genetic differentiation. Despite the minimal genetic structure, our results suggest that seed sourcing from either population is viable for the local mangrove restoration programs in the future.

Geologically recent radiations can shed light on speciation processes, but incomplete lineage sorting and introgressive gene flow render accurate evolutionary reconstruction and interpretation challenging. Independently evolving metapopulations of low dispersal taxa may provide an additional level of phylogeographic information, given sufficiently broad sampling and genome-wide sequencing. Evolution in the marine brown algal genus Fucus in the south-eastern North Atlantic was shaped by Quaternary climate-driven range shifts. Over this timescale, divergence and speciation occurred against a background of expansion-contraction cycles from multiple refugia, together with mating-system shifts from outcrossing (dioecy) to selfing hermaphroditism. We tested the hypothesis that peripheral isolation of range edge (dioecious) F. vesiculosus led to parapatric speciation and radiation of hermaphrodite lineages. Species tree methods using 876 single-copy nuclear genes and extensive geographic coverage produced conflicting topologies with respect to geographic clades of F. vesiculosus. All methods, however, revealed a new and early diverging hermaphrodite species, Fucus macroguiryi sp. nov. Both the multispecies coalescent and polymorphism-aware models (in contrast to concatenation) support sequential paraphyly in F. vesiculosus resulting from distinct evolutionary processes. Our results support (1) peripheral isolation of the southern F. vesiculosus clade prior to parapatric speciation and radiation of hermaphrodite lineages-a "low-latitude species pump". (2) Directional introgressive gene flow into F. vesiculosus around the present-day secondary contact zone (sympatric-allopatric boundary) between dioecious/hermaphrodite lineages as hermaphrodites expanded northwards, supported by concordance analysis and statistical tests of introgression. (3) Species boundaries in the extensive sympatric range are probably maintained by reproductive system (selfing in hermaphrodites) and reinforcement.

Aim Drivers of extant population genetic structure include past climate-driven range shifts and vicariant events, as well as gene flow mediated by dispersal and habitat continuity. Their integration as alternative or complementary drivers is often missing or incomplete, potentially overlooking relevant processes and time scales. Here we ask whether it is the imprint of past range shifts or habitat connectivity driven by oceanographic transport that best explain genetic structure in a poorly understood model, a forest-forming African kelp. Location Southwestern coast of Africa (Benguela current region). Taxon Laminaria pallida. Methods We estimated genetic variability along the species distributional range using 14 microsatellite markers. This genetic variability was compared to estimates of past range shifts derived from species distribution modelling for the Last Glacial Maximum (LGM), the mid-Holocene (MH) and the present, and estimates of habitat connectivity derived from oceanographic biophysical modelling. Results The species is structured in two clusters, a southern cluster with much richer (allelic richness A: 10.40 +/- 0.33) and unique (private alleles PA: 56.69 +/- 4.05) genetic diversity, and a northern cluster (A: 4.75 +/- 0.17; PA: 6.70 +/- 1.45). These clusters matched well-known biogeographical regions and their transition coincided with a dispersal barrier formed by upwelled offshore transport. No major range shifts or vicariant events were hindcasted along the present range, suggesting population stability from the LGM to the present. Main conclusions Habitat connectivity, rather than past range shifts, explains the extant population structure. Future environmental requirements of the species along the Benguela upwelling system are projected to persist or even intensify, likely preserving the observed genetic patterns for the years to come. Yet, the differentiation and endemicity between clusters, and the isolation structured by the regional oceanography, implies high conservation value for genetic biodiversity, and even more if considering the ecological, social and economic services provided by kelp forests.

Green turtles ( Chelonia mydas ) are highly dependent on neritic foraging areas throughout much of their life. Still, knowledge of recruitment dynamics, foraging habits, and habitat use in these areas is limited. Here, we evaluated how the distribution and food preferences of green sea turtles from different life stages varied within a foraging aggregation. We focused on two islands in Guinea-Bissau, Unhocomo and Unhocomozinho, using water captures and survey dives to record habitat use and characteristics, and stable isotopes to infer diet. Additionally, we used stable isotopes to infer their diet. Two habitat types were sampled: deeper (2.26 ± 0.4 m) rocky sites fringed by mangrove with macroalgae, and sandy shallows (1.37 ± 0.12 m) surrounded by rocky reefs with macroalgae and seagrass. The two benthic communities were similar isotopically and in terms of species composition, except for the presence or absence of seagrass, which had unique signatures. We captured 89 turtles ranging from 35 cm to 97 cm in curved carapace length (i.e., juvenile to adult stages). Size distribution was habitat-dependent, with most smaller turtles present in sandy shallows and larger turtles favoring slightly deeper rocky sites. Turtle isotopic signatures differed between the habitat of capture, regardless of size, revealing a marked dichotomy in foraging preference. All turtles fed primarily on macroalgae, mostly rhodophytes. However, individuals captured in sandy habitats had evident seagrass skewed isotopic signatures. Larger turtles may be unable to use the more diverse shallower foraging sites due to increased vulnerability to predation. Despite the proximity of the sampled foraging sites (2.7 km apart), the two foraging subgroups seem to maintain consistently different feeding habits. Our study highlights how heterogeneous green turtle foraging habits can be within populations, even at small geographic scales.