Biogeographic population structure of chimeric blades of porphyra in the northeast atlantic reveals southern rich gene pools, introgression and cryptic plasticity

The genus Porphyra sensu lato (Bangiaceae, Rhodophyta), an important seaweed grown in aquaculture, is the most genetically diverse group of the Class Bangiophyceae, but has poorly understood genetic variability linked to complex evolutionary processes. Genetic studies in the last decades have largely focused on resolving gene phylogenies; however, there is little information on historical population biogeography, structure and gene flow in the Bangiaceae, probably due to their cryptic nature, chimerism and polyploidy, which render analyses challenging. This study aims to understand biogeographic population structure in the two abundant Porphyra species in the Northeast Atlantic: Porphyra dioica (a dioecious annual) and Porphyra linearis (protandrous hermaphroditic winter annual), occupying distinct niches (seasonality and position on the shore). Here, we present a large-scale biogeographic genetic analysis across their distribution in the Northeast Atlantic, using 10 microsatellites and cpDNA as genetic markers and integrating chimerism and polyploidy, including simulations considering alleles derived from different ploidy levels and/or from different genotypes within the chimeric blade. For P. linearis, both markers revealed strong genetic differentiation of north-central eastern Atlantic populations (from Iceland to the Basque region of Northeast Iberia) vs. southern populations (Galicia in Northwest Iberia, and Portugal), with higher genetic diversity in the south vs. a northern homogenous low diversity. For. P. dioica, microsatellite analyses also revealed two genetic regions, but with weaker differentiation, and cpDNA revealed little structure with all the haplotypes mixed across its distribution. The southern cluster in P. linearis also included introgressed individuals with cpDNA from P. dioica and a winter form of P. dioica occurred spatially intermixed with P. linearis. This third entity had a similar morphology and seasonality as P. linearis but genomes (either nuclear or chloroplast) from P. dioica. We hypothesize a northward colonization from southern Europe (where the ancestral populations reside and host most of the gene pool of these species). In P. linearis recently established populations colonized the north resulting in homogeneous low diversity, whereas for P. dioica the signature of this colonization is not as obvious due to hypothetical higher gene flow among populations, possibly linked to its reproductive biology and annual life history.info:eu-repo/semantics/publishedVersio

The Ecology and Management of Urban Pondscapes

<p>Small water bodies provide valuable ‘blue space’ in urban environments, creating a network of semi-natural habitat patches for wildlife as well as providing a wide range of ecosystem services.  However, the diverse and interacting anthropogenic stressors imposed by the urban environment pose considerable challenges for the effective management of these habitats. We outline some of the key factors that appear to influence urban pond biodiversity: land use with the local (and often small-scale) catchment, the connectivity of ponds through the landscape, and the nature of emergent and riparian vegetation. We argue that all three factors can be incorporated into a landscape-scale planning framework that can target particular areas for creation and amelioration of pond habitats.  Such a joined-up approach is currently lacking from most urban planning frameworks, but could provide an opportunity to maximise services provided by urban wetlands at the landscape scale.  We emphasise the application of recent ecological advances in our understanding of urban ponds to management guidelines, which have largely come in the form of gardening guides. This management will be required not only to enhance the biodiversity value of urban ponds, but also to control the less desirable elements of aquatic biodiversity such as invasive species and disease vectors that may pose a particular risk in urban environments.  Finally, we note the lack of a comprehensive conservation strategy for ponds and highlight key legislation and guidance that can help to fill the gap. The fact that pond value lies in the aggregation of multiple habitats distributed through the landscape challenges our existing approach to habitat protection.  However, contemporary approaches to pond creation for mitigation through planning processes and programmes of pond creation provide an opportunity to implement truly large-scale strategic habitat management. It is imperative that ecologists and conservationists are involved in the future planning process and its implementation.</p