Biology subjects

Serrao, E. A.

Publications and source records attributed to Serrao, E. A..

6 recordsLinked to original sources

bioRxiv2026

Genomic footprints of selfing, introduction history, and long-distance dispersal in an invasive alien plant

Biological invasions are natural experiments for studying the evolutionary and ecological processes underlying colonization success and range expansion. Using genome-wide data -- generated via genotyping-by-sequencing (GBS) from 30 populations spanning Europe and South Africa-- we investigated the colonization history and successful spread of the invasive buttonweed Cotula coronopifolia, an annual plant introduced into Europe from South Africa about 300 years ago. Our analyses identified three major lineages in Europe distributed across the continent, often co-occurring without evidence of admixture. Phylogenomic dating revealed that these lineages diverged > 2,000 years ago --well before the earliest European records-- suggesting divergence within the native range and either multiple introductions or a single introduction with multiple lineages. Mating-system inference shows that reproduction occurs primarily via self-fertilization ([~]70% on average), although outcrossing predominates in some populations, revealing a facultative mating system. This high selfing rate has led to extremely low heterozygosity in most populations and a strong genetic structure. Genetic clustering also revealed admixed individuals resulting from rare inter-lineage outcrossing; comparisons of empirical and simulated data indicate that increased diversity after sporadic admixture events decays rapidly under subsequent selfing. Both the introduction history and long-distance dispersal facilitated by waterbirds likely explain the scattered distribution of lineages across Europe. Altogether, these results provide an empirical demonstration of Bakers "ideal weed" concept, highlighting the role of a flexible mating system in providing reproductive assurance during colonization and showing how predominant selfing shapes the genomic landscape of an invasive species. SIGNIFICANCE STATEMENTUnderstanding how reproductive strategies influence colonization and spread of alien species is central to invasion biology. By combining population genomics and phylogenomic inference, this study provides key insights into the colonization history and successful invasion of the self-fertilizing plant C. coronopifolia, introduced from South Africa to Europe in the 18th century. We show that the species invasion success relies on the introduction of multiple lineages and the predominance of selfing, which has drastically reduced genetic diversity yet contributed to reproductive assurance and spread across diverse habitats. Occasional outcrossing and long-distance dispersal by waterbirds or through horticultural transport have further shaped the species genetic landscape. These findings illustrate how self-compatibility and ecological generalism can overcome genetic constraints during range expansion and provide the basis for understanding the evolutionary dynamics of selfing plant invasions.

genomics↗

bioRxiv2025

SAMMBA is a high-throughput pipeline for isolating and phenotyping macroalgal strains

Anthropogenic climate change is causing the decline of seaweed forests in many parts of the world. Despite successful preservation efforts, their immense biodiversity is still severely underrepresented in germplasm biobanks throughout the world. These culture libraries can preserve genetic diversity and provide inoculum for marine forest restoration and mariculture ventures, and potentially accelerate the selection and breeding of climate-resilient and high-yielding strains. However, the complex life cycles and body plans of seaweeds pose a huge challenge for the development of standardized phenotyping and isolating protocols for microscopic stages, especially with the efficiency necessary to deal with the current pace of global climatic changes. Here, we present SAMMBA (Seaweed Automatable Microplate Microscopy for Breeding Approaches), an end-to-end pipeline for the high-throughput isolation, phenotyping and storage of macroalgal cells in 384-well plates (384WP). By optimizing fluorescence microscopy imaging and analysis, along with a novel fragmentation method and dilution-to-extinction isolation, different unialgal seaweed tissues could be regrown after thousand-fold dilutions. In a single plate, we successfully isolated 68 singlet gametophyte fragments of Laminaria ochroleuca (39 males, 29 females; 17.7% efficiency) and 60 spores of Phyllariopsis purpurascens (31.25% efficiency). Furthermore, the taxonomic versatility of SAMMBA was demonstrated through the successful isolation of 60 unialgal cultures of red algae (Halymenia sp., Hydrolithon sp., Erythrotrichia sp.) and 10 strains of the green alga Ulva sp, without cross-contamination. The viability and unialgal nature of the isolated strains were verified by distributing a single L. ochroleuca strain across an entire 384-well plate and imaging each well over 30 days. We found that the average specific daily growth rates (daily SGR) per well were 0.130 {+/-} 0.006 and 0.117 {+/-} 0.01 day-1 for males and females, respectively, showing a significant difference between sexes (n = 768; p = 1.27e-53), while edge effects significantly reduced daily SGR in males but not in females. This approach dramatically increases experimental reproducibility and statistical power compared to conventional methods. Due to its modular design and cost-effectiveness, SAMMBA is readily adaptable to macroalgal repositories globally. It supports high-throughput, selective recovery of unialgal strains without reliance on robotic platforms, while remaining fully compatible with automation. This system significantly expands the experimental and operational capacity in macroalgal hatcheries, providing a scalable foundation for phenomics, domestication programs, and standardized, verifiable biobanking of unialgal strains. Ultimately, SAMMBA could provide critical support for breeding strategies required to ensure the resilience of marine forests and aquaculture in a rapidly changing ocean.

plant biology↗

bioRxiv2024

Hotspot of Exotic Benthic Marine Invertebrates Discovered in the Tropical East Atlantic: DNA Barcoding Insights from the Bijagos Archipelago, Guinea-Bissau

AimThis study aimed to explore and document putative exotic marine benthic invertebrate species in the Bijagos Archipelago, Guinea-Bissau, to enhance understanding of marine biodiversity and address the extent of marine species introductions. LocationThe research was conducted in the Bijagos Archipelago, a UNESCO Biosphere Reserve located in Guinea-Bissau. MethodsThe study involved the regions first scuba-diving survey of marine biodiversity. DNA barcoding was employed to assist in the identification of benthic invertebrate species. Molecular phylogenetic analyses were conducted with the available DNA barcodes to ensure accurate taxonomic assignments, detect cryptic species, and investigate the phylogeography of the taxa. ResultsThe survey resulted in the discovery of 28 new species records for the Bijagos Archipelago, including octocorals, scleractinians, hydroids, bryozoans, barnacles, and ascidians. Among these, seven species were documented for the first time in the East Atlantic: Stragulum bicolor, Tubastraea tagusensis, Nemalecium lighti, Diphasia sp., Amathia alternata, A. distans, and Symplegma rubra. Molecular analyses revealed pervasive cryptic diversity within species previously listed as exotic, suggesting that some, such as the hydroids Plumularia setacea, Obelia geniculata, and Dynamena disticha, are not exotic due to their restricted biogeographic distributions. Many other species reported as introduced present only a few genetic lineages capable of long-distance dispersal due to human activities. Main ConclusionsThe study highlights considerable gaps in the knowledge of West African marine biodiversity and suggests a substantial underestimation of the anthropogenic trade in exotic marine species between the Tropical East Atlantic and the Americas, and between the Indo-Pacific and West Africa. Detailed taxonomic and genomic analyses are necessary for understanding marine exotic species biogeography and adaptive traits. Our findings challenge current classifications of exotic species and underscore the need for improved monitoring and management to prevent the spread of non-native marine species.

zoology↗

bioRxiv2024

Coastal oceanographic connectivity estimates at the global scale

MotivationOceanographic connectivity driven by ocean currents is critical in determining the distribution of marine biodiversity. It mediates the genetic and individual exchange between populations, from structuring dispersal barriers that promote long-term isolation to enabling long-distance dispersal that underpins species expansion and resilience against climate change. Despite its significance, comprehensive estimates of oceanographic connectivity on a global scale remain unavailable, while traditional approaches, often simplistic, fail to capture the complexity of oceanographic factors contributing to population connectivity. This gap hinders a deeper understating of species dispersal ecology, survival, and evolution, ultimately precluding the development of effective conservation strategies aimed at preserving marine biodiversity. To address this challenge, we present a comprehensive dataset of connectivity estimates along the worlds coastlines, known for their rich marine biodiversity. These estimates are derived from a biophysical modelling framework that combines high-resolution ocean current data with graph theory to predict multi-generational stepping-stone connectivity. Alongside, we provide coastalNet, an R package designed to streamline access, analysis, and visualization of connectivity estimates. This tool enhances the utility and application of the data, adhering to the FAIR principles of Findability, Accessibility, Interoperability, and Reusability. The dataset and package set a new benchmark for research in oceanographic connectivity, allowing a better exploration of the complex dynamics of coastal marine ecosystems. Main types of variables containedPairwise connectivity estimates (probability and time) between coastal sites. Spatial location and grainGlobal, equal-area hexagons with 8.45 km edge length. Time period and grainDaily, from 2000 to 2020. Major taxa and level of measurementCoastal marine biodiversity. Software formatA package of functions developed for R software.

ecology↗

bioRxiv2023

Non-indigenous seaweeds in the Northeast Atlantic Ocean, the Mediterranean Sea and Macaronesia: a critical synthesis of diversity, spatial and temporal patterns

Effective monitoring and combatting the effect of non-indigenous seaweeds relies on a solid confirmation of the non-indigenous status of the species. We critically analysed the status of presumed non-indigenous seaweed species reported from the Mediterranean Sea, the Northeast Atlantic Ocean and Macaronesia, resulting in a list of 140 species whose non-indigenous nature is undisputed. For an additional 87 species it is unclear if they are native or non-indigenous (cryptogenic species) or their identity requires confirmation (data deficient species). We discuss the factors underlying both taxonomic and biogeographic uncertainties and outline recommendations to reduce uncertainty about the non-indigenous status of seaweeds. Our dataset consisted of over 19,000 distribution records, half of which can be attributed to only five species (Sargassum muticum, Bonnemaisonia hamifera, Asparagopsis armata, Caulerpa cylindracea and Colpomenia peregrina), while 56 species (40%) are recorded no more than once or twice. In addition, our analyses revealed considerable variation in the diversity of non-indigenous species between the geographic regions. The Eastern Mediterranean Sea is home to the largest fraction of non-indigenous seaweed species, the majority of which have a Red Sea or Indo-Pacific origin and have entered the Mediterranean Sea mostly via the Suez Canal. Non-indigenous seaweeds with native ranges situated in the Northwest Pacific make up a large fraction of the total in the Western Mediterranean Sea, Lusitania and Northern Europe, followed by non-indigenous species with a presumed Australasian origin. Uncertainty remains, however, regarding the native range of a substantial fraction of non-indigenous seaweeds in the study area. In so far as analyses of first detections can serve as a proxy for the introduction rate of non-indigenous seaweeds, these do not reveal a decrease in the introduction rate, indicating that the current measures and policies are insufficient to battle the introduction and spread of non-indigenous species in the study area. HighlightsO_LINon-indigenous seaweed species in the Northeast Atlantic Ocean, the Mediterranean Sea and Macaronesia are critically reanalysed. C_LIO_LI>19,000 distribution records revealed considerable variation in diversity of non-indigenous seaweed species in the study area. C_LIO_LITaxonomic and biogeographic uncertainties hamper a critical evaluation of the non-indigenous status of many seaweed species. C_LI

plant biology↗

bioRxiv2018

Individual based genetic analyses support asexual hydrochory dispersal in Zostera noltei

Dispersal beyond the local patch in clonal plants was typically thought to result from sexual reproduction via seed dispersal. However, evidence for the separation, transport by water, and re-establishment of asexual propagules (asexual hydrochory) is mounting suggesting other important means of dispersal in aquatic plants. Using an unprecedented sampling size and microsatellite genetic identification, we describe the distribution of seagrass clones along tens of km within a coastal lagoon in Southern Portugal. Our spatially explicit individual-based sampling design covered 84 km2 and collected 3 185 Zostera noltei ramets from 803 sites. We estimated clone age, assuming rhizome elongation as the only mechanism of clone spread, and contrasted it with paleo-oceanographic sea level change. We also studied the association between a source of disturbance and the location of large clones. A total of 16 clones were sampled more than 10 times and the most abundant one was sampled 59 times. The largest distance between two samples from the same clone was 26.4 km and a total of 58 and 10 clones were sampled across more than 2 and 10 km, respectively. The number of extremely large clone sizes, and their old ages when assuming the rhizome elongation as the single causal mechanism, suggests other processes are behind the span of these clones. We discuss how the dispersal of vegetative fragments in a stepping-stone manner might have produced this pattern. We found higher probabilities to sample large clones away from the lagoon inlet, considered a source of disturbance. This study corroborates previous experiments on the success of transport and re-establishment of asexual fragments and supports the hypothesis that asexual hydrochory is responsible for the extent of these clones.

ecology↗