Raquel Fernandes

Understanding the distribution and diversity of invasive alien species is increasingly crucial to meet legal requirements and guide effective management. Portugal currently hosts a large number of invasive alien plant species, with significant environmental and socio-economic impacts. However, the distribution of most of these species across the territory and the factors driving their spread and diversity remain largely unexplored. To address this, we present the first atlas of invasive alien plants in mainland Portugal. A total of 96 terrestrial and aquatic invasive alien plants are presented, encompassing all species listed under Portuguese national legislation and the European Union’s list of invasive species of concern. Occurrence data were collected from a broad array of sources, including national and international biodiversity observation databases, citizen science data, literature, and data collections owned by managers and researchers—totaling approximately 85,000 records, with a mean of 879 records per species (range: 1–9,190). Each species was characterized based on multiple distributional parameters, and a k-means analysis was used to group species with similar distribution patterns. The richness of invasive plants was mapped at the municipality level. The drivers of their spatial variation were investigated using a comprehensive set of 30 variables representing multiple environmental and human factors. Results show that invasive plants are present in all mainland Portuguese municipalities but with high variability. Four main patterns of distribution were identified: species primarily located along the coast (e.g., Acacia saligna ) and a gradient of species with narrow (e.g., Reynoutria japonica ), moderate (e.g., Ipomoea indica ), and wide distribution ranges (e.g., Cortaderia selloana ). Invasive species richness was significantly higher in coastal and larger municipalities, particularly those closer to major urban centers and with a higher density of power lines. Our results provide the first comprehensive assessment of the distribution of invasive alien plants in mainland Portugal, establishing a much-needed baseline for future invasion prevention and management efforts.

Understanding the distribution and diversity of invasive alien species is increasingly vital to meet legal requirements and guide effective management. Portugal currently hosts a large number of invasive alien plant species, with significant environmental and socio-economic impacts. However, the distribution of most of these species in the territory and the factors driving their spread and diversity remain largely unexplored. To address this, we present the first atlas of invasive plants in mainland Portugal. A total of 96 terrestrial and aquatic invasive plants are represented, encompassing all species listed under Portuguese national legislation and the European Union’s list of invasive species of concern. Occurrence data were collected from a broad array of sources, including national and international biodiversity observation databases, citizen science data, literature, and data collections owned by managers and researchers, totaling approximately 85,000 records (mean = 879 ± 1,757 per species). Each species was characterized based on multiple distributional parameters, and a k-means analysis was used to group species with similar distribution patterns. The richness of invasive plants was mapped at the municipality level, and the drivers of their spatial variation were investigated using a comprehensive set of 30 variables representing multiple environmental and human factors. Results show that invasive plants occur in all mainland Portuguese municipalities, but with high variability. Four main patterns of distribution were identified: species that are primarily located along the coast (e.g., Acacia saligna ), and a gradient of species with narrow (e.g., Reynoutria japonica ), moderate (e.g., Ipomoea indica ), and wide distribution ranges (e.g., Cortaderia selloana ). Species richness was significantly higher in coastal and larger municipalities, particularly those closer to major urban centers and with a higher density of power lines. Our results provide the first comprehensive assessment of the distribution of invasive alien plants in mainland Portugal, establishing a much-needed baseline for future invasion prevention and management efforts.

Recent efforts have compiled distribution data on Iberian Peninsula peatlands, however, the criteria used to characterise these ecosystems have often been derived from regions where peatlands are more extensive and typically occur under wetter climatic conditions. As a result, many peat-accumulating wetlands in this region were overlooked. Identifying and improving the distribution mapping of peatlands is crucial for their conservation and management. Here, we present an updated geographical dataset of peatlands and swobs —i.e. wetlands with a potential to form peat— of the Iberian Peninsula. Peatland and swob records in Portugal and Spain were compiled through an extensive literature review, also incorporating data from recently published Iberian peatland maps. Additionally, field surveys conducted between 2011–2015, 2018–2021, and 2023–2024 provided additional records. A total of 445 records were included in the database, representing the current knowledge on the distribution of Iberian peatlands and swobs. This dataset allows the identification of occurrence hotspots, highlights underrepresented regions, and provides a foundation for future research and conservation planning.

Ecosystems with a naturally accumulated peat layer at the surface and wetlands with or without a peat layer dominated by a vegetation that may produce peat (hereafter 'peatlands' for simplicity) are critical assets in global change due to their large carbon content storage capacity and essential ecosystem services. A Global Peatland Assessment was initiated during the UNFCCC COP22; however, many countries still lack accurate peatland maps. This is particularly concerning in the Western Mediterranean, where these ecosystems are frequently overlooked or misclassified. To help address this issue, we developed predictive distribution models for vascular plant and bryophyte species typical of peatland-type systems in the Western Mediterranean. We identified 28 'indicator' mire-typical plant taxa and created a database using filtered data from six different data sources, including our own field surveys. Thirteen high-resolution spatial predictor variables, covering topographic, soil, and hydroclimatic factors, were selected to reflect potential relationships with species presence. For each species, a potential distribution model was built using MaxEnt software. The resulting potential-distribution maps were cross-validated, and models with an AUC score of ≥0.75 were classified into suitable or unsuitable areas. The species richness map aligned well with areas known to support peatlands. The indicator species-based mapping also suggests a broad potential for yet unrecorded peatlands in the Western Mediterranean, including small areas, particularly along the western and southwestern sandy coastlines and in the southern mountains.

Iberian peatlands have been severely affected by land use and land cover (LULC) changes. Despite these pressures, some peatlands persist in the region, although their susceptibility to LULC change remains poorly understood. This study presents the most detailed and extensive distribution data for Iberian peatlands to date and analyzes the dynamics and drivers of LULC in Iberian peatlands and their surrounding areas. We compiled peatland records from various sources and used Corine Land Cover Change layers to determine LULC shifts for 1990, 2000, 2006, 2012, and 2018. Environmental and socioeconomic variables were used to create Boosted Regression Tree models explaining spatial variations in the mean percentage of changed area. Analysis of 270 peatland locations in the Iberian Peninsula revealed that forests and seminatural areas constituted over 80% of the peatland’s surroundings. Agricultural areas expanded the most, except between 2006 and 2012 when the artificial areas showed more gains. While most areas experienced an average change of 0%-9.51% of the total area, between 1990 and 2018, lowland peatlands (littoral and sublittoral) suffered more intense changes (9.51% to 38.43%). Our models showed that only elevation and agricultural area density were relevant predictors of spatial distribution changes. Upland Iberian peatlands showed lower susceptibility to LULC changes, while lowland peatlands underwent remarkable transformations. This study substantially expands previous knowledge about the distribution and conservation needs of these ecosystems in the Iberian Peninsula, especially those in littoral and sublittoral lowlands.

Heatwaves are an extreme meteorological event in which affected populations may also be exposed to deteriorated air quality conditions due to the increase in air pollutant concentrations, such as PM₁₀ (particulate matter < 10 µg/m³). In order to identify heatwaves (1973–2019) in the region of Faro (Algarve) during the hot season (April–September), the Excess Heat Factor (EHF) index was applied. The Mann–Kendall test revealed an upward trend in three heatwave metrics in Faro, and the trend of accumulated heat load (EHF load) was also positive as would be expected, but its signal was not statistically significant. An inventory of North African dust events (2006–2019) was made, and their simultaneous occurrence with heatwaves was assessed, pointing to only 20% of dust events of the Sahara occurring simultaneously with heatwave days. A cluster analysis was conducted on daily geopotential height fields at 850 hPa level over the 2006–2019 period, and four distinct patterns were identified as the most prominent synoptic circulations promoting both heatwave conditions and North African dust over the Algarve.