Cercant els refugis de l'Orella d'ós

Durant el Període Quaternari, moltes espècies vegetals van sobreviure a les glaciacions perquè es trobaven en zones protegides de les extremes condicions climatològiques. Una d'aquestes espècies és l'Orella d'ós (Ramonda myconi ), considerada un fòssil vivent. Investigadors del CREAF han analitzat la seva variabilitat genètica per esbrinar quines zones van actuar com a possibles refugis.Durante el Período Cuaternario, muchas especies vegetales sobrevivieron a las glaciaciones porque se hallaban en zonas protegidas de las extremas condiciones climatológicas. Una de estas especies es la Oreja de oso (Ramonda myconi), considerada un fósil viviente. Investigadores del CREAF han analizado su variabilidad genética para conocer qué zonas actuaron como posibles refugios

Demography, genetic diversity and expansion load in the colonizing species Leontodon longirostris (Asteraceae) throughout its native range

Unravelling the evolutionary processes underlying range expansions is fundamental to understand the distribution of organisms, as well as to predict their future responses to environmental change. Predictions for range expansions include a loss of genetic diversity and an accumulation of deleterious alleles along the expansion axis, which can decrease fitness at the range-front (expansion load). In plants, empirical studies supporting expansion load are scarce, and its effects remain to be tested outside a few model species. Leontodon longirostris is a colonizing Asteraceae with a widespread distribution in the Western Mediterranean, providing a particularly interesting system to gain insight into the factors that can enhance or mitigate expansion load. In this study, we produced a first genome draft for the species, covering 418 Mbp (~53% of the genome). Although incomplete, this draft was suitable to design a targeted sequencing of ~1.5 Mbp in 238 L. longirostris plants from 21 populations distributed along putative colonization routes in the Iberian Peninsula. Inferred demographic history supports a range expansion from southern Iberia around 40,000 years ago, reaching northern Iberia around 25,000 years ago. The expansion was accompanied by a loss of genetic diversity and a significant increase in the proportion of putatively deleterious mutations. However, levels of expansion load in L. longirostris were smaller than those found in other plant species, which can be explained, at least partially, by its high dispersal ability, the self-incompatible mating system, and the fact that the expansion occurred along a strong environmental cline

Evaluating the extent and impact of the extreme Storm Gloria on Posidonia oceanica seagrass meadows

Extreme storms can trigger abrupt and often lasting changes in ecosystems by affecting foundational (habitat-forming) species. While the frequency and intensity of extreme events are projected to increase under climate change, its impacts on seagrass ecosystems remain poorly documented. In January 2020, the Spanish Mediterranean coast was hit by Storm Gloria, one of the most devastating recent climate events in terms of intensity and duration. We conducted rapid surveys of 42 Posidonia oceanica meadows across the region to evaluate the extent and type of impact (burial, unburial and uprooting). We investigated the significance of oceanographic (wave impact model), geomorphological (latitude, depth, exposure), and structural (patchiness) factors in predicting impact extent and intensity. The predominant impact of Storm Gloria was shoot unburial. More than half of the surveyed sites revealed recent unburial, with up to 40 cm of sediment removed, affecting over 50 % of the meadow. Burial, although less extensive, was still significant, with 10–80 % of meadow cover being buried under 7 cm of sediment, which is considered a survival threshold for P. oceanica. In addition, we observed evident signs of recently dead matte in some meadows and large amounts of detached drifting shoots on the sea bottom or accumulated as debris on the beaches. Crucially, exposed and patchy meadows were much more vulnerable to the overall impact than sheltered or continuous meadows. Given how slow P. oceanica is able to recover after disturbances, we state that it could take from decades to centuries for it to recoup its losses. Seagrass ecosystems play a vital role as coastal ecological infrastructure. Protecting vulnerable meadows from anthropogenic fragmentation is crucial for ensuring the resilience of these ecosystems in the face of the climate crisis.This study was funded by the CSIC project “Effects of storm Gloria on the western Mediterranean meadows (202030E052) and “Storms of change: as phenomena extreme weather alters Mediterranean coastal ecosystems, their services and their perception by society" (PID2020-113745RB-I00), state program of I+D+I Oriented to the Challenges of the Society and within the framework of the activities of the Spanish Government through the "Maria de Maeztu Centre of Excellence” accreditation to IMEDEA (CSIC-UIB) (CEX2021-001198). We want to thank the SPAS (Society of Fishing and Underwater Activities of Mataró) and the Mataró City Council, which has financed 25 years of the Alguer de Mataró project

Reassessing global change research priorities in mediterranean terrestrial ecosystems : how far have we come and where do we go from here?

Aim: Mediterranean terrestrial ecosystems serve as reference laboratories for the investigation of global change because of their transitional climate, the high spatiotemporal variability of their environmental conditions, a rich and unique biodiversity and a wide range of socio-economic conditions. As scientific development and environmental pressures increase, it is increasingly necessary to evaluate recent progress and to challenge research priorities in the face of global change. - Location: Mediterranean terrestrial ecosystems. - Methods: This article revisits the research priorities proposed in a 1998 assessment. - Results: A new set of research priorities is proposed: (1) to establish the role of the landscape mosaic on fire-spread; (2) to further research the combined effect of different drivers on pest expansion; (3) to address the interaction between drivers of global change and recent forest management practices; (4) to obtain more realistic information on the impacts of global change and ecosystem services; (5) to assess forest mortality events associated with climatic extremes; (6) to focus global change research on identifying and managing vulnerable areas; (7) to use the functional traits concept to study resilience after disturbance; (8) to study the relationship between genotypic and phenotypic diversity as a source of forest resilience; (9) to understand the balance between C storage and water resources; (10) to analyse the interplay between landscape-scale processes and biodiversity conservation; (11) to refine models by including interactions between drivers and socio-economic contexts; (12) to understand forest-atmosphere feedbacks; (13) to represent key mechanisms linking plant hydraulics with landscape hydrology. - Main conclusions:(1) The interactive nature of different global change drivers remains poorly understood. (2) There is a critical need for the rapid development of regional- and global-scale models that are more tightly connected with large-scale experiments, data networks and management practice. (3) More attention should be directed to drought-related forest decline and the current relevance of historical land use

Time to Switch to Second-line Antiretroviral Therapy in Children With Human Immunodeficiency Virus in Europe and Thailand.

Background: Data on durability of first-line antiretroviral therapy (ART) in children with human immunodeficiency virus (HIV) are limited. We assessed time to switch to second-line therapy in 16 European countries and Thailand. Methods: Children aged <18 years initiating combination ART (≥2 nucleoside reverse transcriptase inhibitors [NRTIs] plus nonnucleoside reverse transcriptase inhibitor [NNRTI] or boosted protease inhibitor [PI]) were included. Switch to second-line was defined as (i) change across drug class (PI to NNRTI or vice versa) or within PI class plus change of ≥1 NRTI; (ii) change from single to dual PI; or (iii) addition of a new drug class. Cumulative incidence of switch was calculated with death and loss to follow-up as competing risks. Results: Of 3668 children included, median age at ART initiation was 6.1 (interquartile range (IQR), 1.7-10.5) years. Initial regimens were 32% PI based, 34% nevirapine (NVP) based, and 33% efavirenz based. Median duration of follow-up was 5.4 (IQR, 2.9-8.3) years. Cumulative incidence of switch at 5 years was 21% (95% confidence interval, 20%-23%), with significant regional variations. Median time to switch was 30 (IQR, 16-58) months; two-thirds of switches were related to treatment failure. In multivariable analysis, older age, severe immunosuppression and higher viral load (VL) at ART start, and NVP-based initial regimens were associated with increased risk of switch. Conclusions: One in 5 children switched to a second-line regimen by 5 years of ART, with two-thirds failure related. Advanced HIV, older age, and NVP-based regimens were associated with increased risk of switch

Noves aportacions a la flora de les comarques meridionals de Catalunya.

Data about 89 taxa are presented. Arabis nova Vill. subsp. iberica Rivas Mart. ex Talavera, Cistus × nigricans Pourr. and Phacelia tanacetifolia Benth. are new records for the Catalan flora, and 15 taxa (Allium oporinanthum Brullo et al., Apera interrupta (L.) Beauv., Asplenium trichomanes L. subsp. trichomanes, Campanula affinis Schult., Carex sylvatica Huds. subsp. paui (Sennen) A. and O. Bolòs, Epilobium angustifolium L., Limonium hibericum Erben, Melilotus messanensis (L.) All., Minuartia funkii (Jord.) Graebner, Onosma triceros-perma subsp. catalaunica (Sennen) O. Bolòs and Vigo, Orchis palustris Jacq., Orchis simia Lam., Selaginella denticulata (L.) Spring, Stellaria neglecta Weihle in Bluff and Fingerh. and Vaccinium myrtillus L. are new records for Southern Catalonia

Thymus herba-barona subsp. bivalens, a new endemic taxon from the Balearic Islands

Se describe un nuevo taxón (Thymus herba-barona subsp. bivalens) de la zona montañosa de Mallorca que se distingue del tipo por ser diploide (2n=28), presentar hojas glabras (con algunos tricomas pluricelulares en el haz), dientes inferiores del cáliz menores y la longitud del tubo mayor que los dientes calicinales.A new diploid subspecies of Thymus herba-barona is described from Mallorca. It differs from the typical subspecies by a different indumenta on the leaves and several calyx features

Thymus herba-barona subsp. bivalens, a new endemic taxon from the Balearic Islands

Se describe un nuevo taxón (Thymus herba-barona subsp. bivalens) de la zona montañosa de Mallorca que se distingue del tipo por ser diploide (2n=28), presentar hojas glabras (con algunos tricomas pluricelulares en el haz), dientes inferiores del cáliz menores y la longitud del tubo mayor que los dientes calicinales.A new diploid subspecies of Thymus herba-barona is described from Mallorca. It differs from the typical subspecies by a different indumenta on the leaves and several calyx features

Environmental patterns of adaptation after range expansion in Leontodon longirostris : The effect of phenological events on fitness‐related traits

Premise Because of expected range shifts associated with climate change, there is a renewed interest in the evolutionary factors constraining adaptation, among which are genetic bottlenecks, drift, and increased mutational load after range expansion. Here we study adaptation in the short-lived species Leontodon longirostris showing reduced genetic diversity and increased genetic load along an expansion route. Methods We assessed the phenological patterns of variation, and their effect on fitness-related traits, on 42 L. longirostris populations and six populations of the sister taxa L. saxatilis in a common garden located within the current range of both species. The comparison among L. longirostris populations allowed us to test for genetic clines consistent with local adaptation, whereas the comparison between taxa provided evidence for common adaptive features at the species level. Results We found significant within-species variability for most traits, as well as differences with its close relative L. saxatilis. In general, seeds from drier, warmer, and unpredictable habitats showed overall lower and more restricted conditions for germination, seedlings emerged later and plants flowered earlier. Consequently, genotypes from arid and unpredictable environments attained smaller reproductive sizes and allocated more biomass to reproduction. Flowering time had the strongest direct effect on total plant size, but seedling emergence also showed an important indirect effect. Conclusions Our results show the crucial role of phenological patterns in shaping adaptive clines for major life-history stage transitions. Furthermore, the genetic load observed in L. longirostris does not seem to preclude adaptation to the climatic variability encountered along the expansion route