► Biotic homogenization is observed in French agroecosystems. ► In High Nature Value farmland this phenomenon is potentially refrained. ► Farmland Bird Indicator trends remain high in recent non High ...Nature Value farmlands.
High Nature Value (HNV) farmlands are expected to support high levels of biological diversity and may have a relevant role in driving biodiversity dynamics and particularly refraining biotic homogenization. The present study tests this hypothesis by examining whether spatial and temporal variations in contemporary composition and dynamics of bird communities are related to past changes in HNV farmland within a 30-year period. Analyses of three farmland types were made in areas of (1) highly intensified agriculture, (2) relatively recent agriculture intensification and (3) low-intensity agriculture identified as HNV farmlands. French farmland in its whole is currently subjected to biotic homogenization processes. However, no homogenization was observed in HNV farmland, potentially indicating that those areas were not affected – or at least not at the same pace as elsewhere – by biotic homogenization. Farmland species population trends remain high in recent non-HNV farmlands, indicating that some non-HNV areas may still contribute in refraining farmland biodiversity decline. Future conservation focus should be given in priority in HNV farmland, but also in areas of recent agriculture intensification, to buffer further negative effects on population and community dynamics.
Anticipating and mitigating the impacts of climate change on biodiversity requires a comprehensive understanding on key habitats utilized by species. Yet, such information for high mobile marine ...megafauna species remains limited. Here, we compile a global database comprising published satellite tracking data (n = 1035 individuals) to spatially delineate foraging grounds for seven sea turtle species and assess their thermal stability. We identified 133 foraging areas distributed around the globe, of which only 2% of the total surface is enclosed within an existing protected area. One-third of the total coverage of foraging hotspots is situated in high seas, where conservation focus is often neglected. Our analyses revealed that more than two-thirds of these vital marine habitats will experience new sea surface temperature (SST) conditions by 2100, exposing sea turtles to potential thermal risks. Our findings underline the importance of global ocean conservation efforts, which can meet climate challenges even in remote environments.
•Foraging areas of juveniles cover extensive areas at central and west Mediterranean.•Foraging sites of both juveniles and adults will experience future redistribution.•Important areas for both ...juveniles and adults are hosted across the basin.•Important areas for both juveniles and adults are predicted to expand in future.•Climatically stable areas for both life stages are hosted mainly in neritic zone.
Identification of important habitats of charismatic marine megafauna is essential to enhance our conservation capacity. Still, for species such as sea turtles that have a long-life span, a complex life history and a highly migratory nature, spatially delineating important marine areas is not a simple task. Even in the case that such areas are identified, our ability to draw effective measures and propose conservation prioritization schemes faces additional challenges, due to the dynamic climate-driven redistribution of habitats. Here, we compile a database on foraging locations of loggerhead sea turtles across the Mediterranean Sea and use climatic niche models to predict the distribution of foraging grounds for juvenile and adult life stages. We explore potential shifts due to future changes in ocean temperature and identify sites, considered as important for both life stages, that will persist under climate change. We found extensive areas which could host foraging sites for juvenile loggerheads, distributed at the central and western Mediterranean, while adults’ foraging grounds had a more sparse and patchy distribution, mostly at the central and eastern part of the basin. Under future changes, expansions prevail over contractions, but projected redistribution of foraging space for both life stages will probably lead to remarkable losses of climatic suitability at certain sites. The coverage of important areas, hosted primarily at the neritic zone, will be extended in the future. Our analyses add a missing dimension to conservation efforts, related to the basin-wide distribution of important areas, offering novel insights towards incorporating climate change into conservation planning.
Abstract
A potential strategy for marine species to cope with warming oceans is to track areas with optimal thermal conditions and shift their spatial distributions. However, the ability of species ...to successfully reach these areas in the future depends on the length of the paths and their exposure to extreme climatic conditions. Here, we use model predictions of sea surface temperature changes to explore climate connectivity and potential trajectories of marine species to reach their optimal surface thermal analogs by the end of the century. We find that longer trajectories may be required for marine species of the northern than the southern oceans and that the former may be more exposed to extreme conditions than the latter. At key biodiversity hotspots, most future surface thermal analogs may be located in very remote areas, posing a significant challenge for local species to reach them. The new marine connectivity approach presented here could be used to inform future conservation policies.
Trees play a key role in the structure and function of many ecosystems worldwide. In the Mediterranean Basin, forests cover approximately 22% of the total land area hosting a large number of endemics ...(46 species). Despite its particularities and vulnerability, the biodiversity of Mediterranean trees is not well known at the taxonomic, spatial, functional, and genetic levels required for conservation applications. The WOODIV database fills this gap by providing reliable occurrences, four functional traits (plant height, seed mass, wood density, and specific leaf area), and sequences from three DNA-regions (rbcL, matK, and trnH-psbA), together with modelled occurrences and a phylogeny for all 210 Euro-Mediterranean tree species. We compiled, homogenized, and verified occurrence data from sparse datasets and collated them on an INSPIRE-compliant 10 × 10 km grid. We also gathered functional trait and genetic data, filling existing gaps where possible. The WOODIV database can benefit macroecological studies in the fields of conservation, biogeography, and community ecology.
Although environmental heterogeneity (EH) has recently gained increasing attention, its connection to conservation planning still remains limited. We aim to assess the efficiency of Rao's quadratic ...entropy for measuring EH and conducting prioritization schemes. We focus on EH priority areas in the European Mediterranean biome and we estimate to which extent they are included in national and international protected area networks. We estimate Rao and Shannon EH indices for the bioclimatic and topographic variables of the CHELSA and the ENVIREM datasets. We use systematic conservation planning algorithms, for each dataset and for several moving window extends and we estimate the overlaps among the different schemes.
The Rao and Shannon EH indices do not measure EH levels in a similar way and Shannon indices tend to overestimate EH comparing to Rao. The overlaps between the ENVIREM and CHELSA prioritization schemes are moderate (Jaccard index = 0.4–0.6) and not sensitive to the moving window extend. We consider only the priority areas that are identified as such by both independent datasets. One third of the EH priority areas are located in Greece, one forth in Italy and one fifth in France and Spain. Only one third of the EH priority areas are located within nationally designated protected areas and up to half are located in Key Biodiversity Areas and the Natura 2000 network.
We conclude that Rao's methodology should be further used for environmental heterogeneity analyses. EH priority conservation areas are only partially included in protected area networks, mostly in mountainous areas.
•Environmental heterogeneity (EH) metrics can be useful for conservation planning.•Shannon entropy tends to overestimate EH compared to Rao's quadratic entropy.•EH priority areas are mostly in mountainous regions in the Euro-Mediterranean biome.•EH priority areas are only partially under protection.•The methodology is applicable even for identifying homogeneous priority areas.
Small and peripheral populations are typically vulnerable to local extinction processes but important for the metapopulation dynamics of species. The Slender-billed gull (Chroicocephalus genei) is a ...long-lived species breeding in unstable ephemeral coastal habitats. Their Western Mediterranean populations are relatively small and represent the edge of their global geographical distribution. At a local scale, using long-term data (14 years) on annual breeding success and capture-resights of marked individuals, we estimated and compared the vital rates and evaluated the connectivity of two Spanish populations (Ebro Delta and Doñana) varying in their local environmental conditions. At a metapopulation scale, we analyzed 22 years of data on breeding numbers to predict their future prospects by means of population demographic models. Local survival and breeding success of gulls from the Ebro Delta was lower than those from Doñana, which is likely the result of higher permanent emigration and/or winter mortality in the former. Gulls from the Ebro Delta wintered mostly in Mediterranean areas whereas those from Doñana did so in Atlantic coasts, where food availability is higher. Whereas adult local survival was constant, juvenile local survival showed temporal parallel variations between colonies, probably related to natal dispersal to other breeding colonies. Our results suggested that dispersal was higher at the Ebro Delta and gulls emigrating from their natal colonies settled preferentially in close patches. We found large fluctuations in breeding numbers among local populations probably related to the fact that the Slender-billed gull is a species adapted to unstable and unpredictable habitats with high abilities to disperse between suitable patches depending on environmental stochastic conditions during breeding.
Angel sharks are among the most threatened species of sharks globally. Twenty-two species have been identified globally so far, with three species being present in the Mediterranean Sea: Squatina ...aculeata, Squatina oculata, and Squatina squatina. The Mediterranean populations of all three species have been assessed as Critically Endangered by the IUCN Red List of Threatened Species due to the steep decline of their populations as a result of their historical and current overexploitation by demersal fisheries. Therefore, currently there is an ongoing increasing effort for advancing the conservation of the species in the basin. Recently, in the context of the Regional Action Plan for Mediterranean Angel Sharks, the Aegean Sea and Crete have been identified as critical areas for all three species. This study provides the first predictive distribution map of the three angel shark species in the basin, while critical areas for the conservation of the species were identified through a systematic spatial conservation planning analysis. Our analysis revealed low overlapping between the existing MPA network and critical areas for the distribution of the species primarily in Greece and then Turkey, while 20% of the critical areas for the distribution of the species overlaps with Fisheries Restricted Areas of the region. This highlights the need for creating MPAs focusing on shark conservation within the Mediterranean that are currently completely absent. In addition, we provide policy recommendations that can secure better protection of angel sharks through the enforcement of the current legislations and the engagement of all relevant stakeholders.
Climate plays a major role in shaping biodiversity patterns over time and space, with ongoing changes leading to the reorganization of ecosystems, which challenges conservation initiatives. ...Identifying areas that could serve as possible climate change refugia for future biodiversity is, thus, critical for both conservation and management. Here, we identify potential future climatic refugia within the Euro‐Mediterranean biome, which is a global biodiversity hotspot, while accounting for multiple emission climate change projections over the next 50 years. We developed two metrics of climatic variability: temporal stability and spatial heterogeneity. We then used a systematic conservation planning approach to identify climate‐based priority areas. While we used a climate‐based, species‐neutral methodology, we deliberately implemented low climatic velocity thresholds, so that the identified climatic refugia would even be compatible with the needs of species with low dispersal capacity, such as plants. Our projections showed that future climatic refugia would be more frequently observed in mid‐altitudes, for gradients with steep elevations, and mainly in the eastern part of the Euro‐Mediterranean biome, with possible conflicts with existing land uses and future conservation implications. Climatic, land use, and topography results indicated that only a limited number of refugia would be hosted by high elevation habitats (>1500 m), raising possible concerns about the biodiversity of Mediterranean mountain regions. Our analyses show that the current network of protected areas captures future climatic refugia disproportionally, despite their importance for safeguarding present and future biodiversity in the Mediterranean. Key climatic refugia could limit the impacts of future climate change on biodiversity in mid‐altitude and mountainous regions, and should be included in management guidelines for a climate‐ready conservation design in the Mediterranean biome.
Based on bioclimatic local heterogeneity and temporal stability metrics, we identify potential future climatic refugia within a global biodiversity hotspot, the Euro‐Mediterranean biome. Our projections show that future climatic refugia would be more frequently observed in mid‐altitudes, for gradients with steep elevations, and mainly in the eastern part of the Euro‐Mediterranean biome. Current protected area networks overlap with future climatic refugia mainly in steep, high‐altitude areas but fail to include lower elevation areas.
PDF
