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Anthropogenic climate change, particularly seawater warming, is expected to drive quick shifts in marine species distribution transforming coastal communities. These shifts in distribution will be particularly noticeable in biogeographical transition zones. The continental Portuguese coast stretches from north to south along 900 km. Despite this short spatial scale, the strong physical gradient intensified by the Iberian upwelling creates a transition zone where seaweed species from boreal and Lusitanian-Mediterranean origin coexist. On the northern coast, kelp marine forests thrive in the cold, nutrient-rich oceanic waters. In the south, communities resemble Mediterranean-type seaweed assemblages and are dominated by turfs. Recent evidence suggests that in these coastal areas, marine intertidal species are shifting their distribution edges as a result of rising seawater temperatures. Taking advantage of previous abundance data collected in 2012 from subtidal seaweed communities, a new sampling program was carried out in the same regions in 2018 to assess recent changes. The results confirmed the latitudinal gradient in macroalgal assemblages. More importantly we found significant structural and functional changes in a short period of six years, with regional increases of abundance of warm-affinity species, small seaweeds like turfs. Species richness, diversity, and biomass increase, all accompanied by an increase of community temperature index (CTI). Our findings suggest that subtidal seaweed communities in this transitional area have undergone major changes within a few years. Evidence of "fast tropicalization" of the subtidal communities of the Portuguese coast are strong indication of the effects of anthropic climate change over coastal assemblages., (© 2023. The Author(s).)

Mapping species' geographical distribution is fundamental for understanding current patterns and forecasting future changes. Living on rocky shores along the intertidal zone, limpets are vulnerable to climate change, as their range limits are controlled by seawater temperature. Many works have been studying limpets' potential responses to climate change at local and regional scales. Focusing on four Patella species living on the rocky shores of the Portuguese continental coast, this study aims to predict climate change impacts on their global distribution, while exploring the role of the Portuguese intertidal as potential climate refugia. Ecological niche models combine occurrences and environmental data to identify the drivers of these species' distributions, define their current range, and project to future climate scenarios. The distribution of these limpets was mostly defined by low bathymetry (intertidal) and the seawater temperature. Independent of the climate scenario, all species will gain suitable conditions at the northern distribution edge while losing in the south, yet only the extent of occurrence of P. rustica is expected to contract. Apart from the southern coast, maintenance of suitable conditions for these limpets' occurrence was predicted for the western coast of Portugal. The predicted northward range shift follows the observed pattern observed for many intertidal species. Given the ecosystem role of this species, attention should be given to their southern range limits. Under the current upwelling effect, the Portuguese western coast might constitute thermal refugia for limpets in the future., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Francisco Arenas reports financial support was provided by Foundation for Science and Technology., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Detailed knowledge about biodiversity distribution is critical for monitoring the biological effects of global change processes. Biodiversity knowledge gaps hamper the monitoring of conservation trends and they are especially evident in the desert biome. Mauritania constitutes a remarkable example on how remoteness and regional insecurity affect current knowledge gaps. Mammals remain one of the least studied groups in this country, without a concerted species checklist, the mapping of regions concentrating mammal diversity, or a national assessment of their conservation status. This work assessed the diversity, distribution, and conservation of land mammals in Mauritania. A total of 6,718 published and original observations were assembled in a spatial database and used to update the occurrence status, distribution area, and conservation status. The updated taxonomic list comprises 107 species, including 93 extant, 12 Regionally Extinct, and 2 Extinct in the Wild. Mapping of species distributions allowed locating concentrations of extant mammal species richness in coastal areas, along the Senegal River valley, and in mountain plateaus. Recent regional extinction of large-sized Artiodactyla and Carnivora has been very high (11% extinct species). From the extant mammals, 11% are threatened, including flagship species (e.g., Addax nasomaculatus and Panthera pardus). Species richness is poorly represented by the current protected areas. Despite the strong advances made, 23% of species categorise as Data Deficient. Persisting systematics and distribution uncertainties require further research. Field surveys in currently unexplored areas (northern and south-eastern regions) are urgently needed to increase knowledge about threatened mammals. The long-term conservation of land mammals in Mauritania is embedded in a complex web of socioeconomic and environmental factors that call for collaborative action and investment in sustainable human development. The current work sets the baseline for the future development of detailed research studies and to address the general challenges faced by mammals and biodiversity in the country., Competing Interests: The authors have declared that no competing interests exist.

Background: The world is undergoing exceptional biodiversity loss. Most conservation efforts target biodiversity hotspots at large scales. Such approach overlooks small-sized local hotspots, which may be rich in endemic and highly threatened species. We explore the importance of mountain rock pools (gueltas) as local biodiversity hotspots in the Sahara-Sahel. Specifically, we considered how many vertebrates (total and endemics) use gueltas, what factors predict species richness, and which gueltas are of most priority for conservation. We expected to provide management recommendations, improve local biodiversity conservation, and simultaneously contribute with a framework for future enhancement of local communities' economy. The identification of local hotspots of biodiversity is important for revaluating global conservation priorities., Methodology/principal Findings: We quantified the number of vertebrate species from each taxonomic group and endemics present in 69 gueltas in Mauritania, then compared these with species present in a surrounding area and recorded in the country. We evaluated the predictors of species number's present in each guelta through a multiple regression model. We ranked gueltas by their priority for conservation taking into account the percentage of endemics and threats to each guelta. Within a mere aggregate extent of 43 ha, gueltas hold about 32% and 78% of the total taxa analysed and endemics of Mauritania, respectively. The number of species present in each guelta increased with the primary productivity and area of gueltas and occurrence of permanent water. Droughts and human activities threaten gueltas, while 64% of them are currently unprotected., Conclusion/significance: Gueltas are crucial for local biodiversity conservation and human activities. They require urgent management plans in Mauritania's mountains. They could provide refugia under climate change being important for long-term conservation of Sahara-Sahel biodiversity. Given their disproportional importance in relation to their size, they are local hotspots of biodiversity deserving global attention.

Deserts and arid regions are generally perceived as bare and rather homogeneous areas of low diversity. The Sahara is the largest warm desert in the world and together with the arid Sahel displays high topographical and climatic heterogeneity, and has experienced recent and strong climatic oscillations that have greatly shifted biodiversity distribution and community composition. The large size, remoteness and long-term political instability of the Sahara-Sahel, have limited knowledge on its biodiversity. However, over the last decade, there have been an increasing number of published scientific studies based on modern geomatic and molecular tools, and broad sampling of taxa of these regions. This review tracks trends in knowledge about biodiversity patterns, processes and threats across the Sahara-Sahel, and anticipates needs for biodiversity research and conservation. Recent studies are changing completely the perception of regional biodiversity patterns. Instead of relatively low species diversity with distribution covering most of the region, studies now suggest a high rate of endemism and larger number of species, with much narrower and fragmented ranges, frequently limited to micro-hotspots of biodiversity. Molecular-based studies are also unravelling cryptic diversity associated with mountains, which together with recent distribution atlases, allows identifying integrative biogeographic patterns in biodiversity distribution. Mapping of multivariate environmental variation (at 1 km × 1 km resolution) of the region illustrates main biogeographical features of the Sahara-Sahel and supports recently hypothesised dispersal corridors and refugia. Micro-scale water-features present mostly in mountains have been associated with local biodiversity hotspots. However, the distribution of available data on vertebrates highlights current knowledge gaps that still apply to a large proportion of the Sahara-Sahel. Current research is providing insights into key evolutionary and ecological processes, including causes and timing of radiation and divergence for multiple taxa, and associating the onset of the Sahara with diversification processes for low-mobility vertebrates. Examples of phylogeographic patterns are showing the importance of allopatric speciation in the Sahara-Sahel, and this review presents a synthetic overview of the most commonly hypothesised diversification mechanisms. Studies are also stressing that biodiversity is threatened by increasing human activities in the region, including overhunting and natural resources prospection, and in the future by predicted global warming. A representation of areas of conflict, landmines, and natural resources extraction illustrates how human activities and regional insecurity are hampering biodiversity research and conservation. Although there are still numerous knowledge gaps for the optimised conservation of biodiversity in the region, a set of research priorities is provided to identify the framework data needed to support regional conservation planning., (© 2013 The Authors. Biological Reviews © 2013 Cambridge Philosophical Society.)