María José Ruiz-López

Historically, Mediterranean systems, particularly the Mediterranean Basin, have been substantially impacted by multiple regional‐scale disturbances resulting from complex interactive effects of global‐change drivers. However, such effects are typically studied on isolated groups of organisms, often disregarding how ecological processes such as biotic interactions affect ecosystem responses to global change. We use the Doñana Protected Area, one of the most important wetlands and shrublands in Europe, as a well‐documented case study to highlight how regional anthropogenic pressures simultaneously affect various interacting species, creating cascading impacts across trophic webs on different ecosystems. Using two examples representing the role of key habitat‐structuring species on ecosystem processes, the cork oak ( Quercus suber ) and European rabbit ( Oryctolagus cuniculus ), we show how decreases in abundance of such key species due to interlinked direct and indirect anthropogenic pressures can alter multitrophic communities—but not always negatively, as other species can adapt to the loss of key species. We also use two examples of species that have flourished under human pressures, the native wild boar ( Sus scrofa ) and invasive red swamp crayfish ( Procambarus clarkii ), and how increases in their abundance have had complex impacts on ecosystems. We then discuss, based on the outcomes of actual conservation actions, how management targeted at single species or taxa is ineffective for ecosystem functioning, as it ignores complex interlinks with other components of the system. Instead, the ecosystem‐wide impacts of gains and losses of interacting species serve as an excellent empirical example for the need for conservation management and research agenda that account for the complexity of global change in the Mediterranean.

Culex pipiens is a major vector of West Nile Virus (WNV) in Europe and has a complex evolutionary history that has been linked to the probability of WNV spillover to humans. Here, we present a population genomic analysis of Cx. pipiens from a WNV hotspot in southwestern Spain. Whole-genome sequencing of 217 individuals from 24 localities revealed that population structure is mainly shaped by the coexistence of pipiens and molestus ecotypes. Despite clustering, genome-wide divergence between ecotypes was low, consistent with shared ancestral variation. Furthermore, Wolbachia infection was heterogeneous across the study area, where some Culex pipiens pipiens remain uninfected. We also identified three new polymorphic chromosomal inversions on chromosomes 1 and 3 that segregate independently. Although inversions did not underlie ecotypic differentiation, they were enriched for genes involved in olfaction and insecticide resistance pathways, suggesting potential adaptive and epidemiological relevance. Distance-based redundancy analyses showed that ecotype identity explained the largest fraction of genetic variance, with additional contributions from Wolbachia infection, habitat type (urban versus rural) and geographic distance. These results reveal that partial ecotypic differentiation, symbiont infection, and habitat interact to shape population structure in Cx. pipiens , with implications for vector ecology and disease transmission.

The reference genomes of Culex laticinctus, Culex modestus, Culex perexiguus, and Culex theileri offer crucial resources for exploring the genetic basis of vector competence for different pathogens, including the emerging West Nile virus. Each genome was assembled into three contiguous chromosomal pseudomolecules. These chromosome-level assemblies encompass 834, 698, 436, and 934 Mb, respectively. They are composed of 3,284, 4,220, 1,917, and 2,704 contigs and 312, 979, 475, and 709 scaffolds, with contig N50 values of 434, 313, 473, and 770 kb, and scaffold N50 values of 292, 246, 150, and 281 Mb, respectively. These genomes offer an essential genomic resource for advancing our understanding of Culex evolution and population genomic analyses, which will help to implement sustainable mosquito control efforts and disease prevention.

West Nile virus (WNV) is the most widely distributed mosquito-borne flavivirus in the world. This flavivirus can infect humans causing in some cases a fatal neurological disease and birds are the main reservoir hosts. WNV is endemic in Spain, and human cases have been reported since 2004. Although different studies analyse how climatic conditions can affect the dynamics of WNV infection, very few use long-term datasets. Between 2003 and 2020 a total of 2,724 serum samples from 1,707 common coots (Fulica atra) were analysed for the presence of WNV-specific antibodies. Mean (SD) annual seroprevalence was 24.67% (0.28) but showed high year-to-year variations ranging from 5.06% (0.17) to 68.89% (0.29). Significant positive correlations (p < 0.01) were observed between seroprevalence and maximum winter temperature and mean spring temperature. The unprecedented WNV outbreak in humans in the south of Spain in 2020 was preceded by a prolonged period of escalating WNV local circulation. Given current global and local climatic trends, WNV circulation is expected to increase in the next decades. This underscores the necessity of implementing One Health approaches to reduce the risk of future WNV outbreaks in humans. Our results suggest that higher winter and spring temperatures may be used as an early warning signal of more intense WNV circulation among wildlife in Spain, and consequently highlight the need of more intense vector control and surveillance in human inhabited areas.

West Nile Virus (WNV) is a mosquito vector-borne zoonosis with an increasing incidence in Europe that has become a public health concern. In Spain, although local circulation has been known for decades, until 2020, when a large outbreak occurred, West Nile Virus cases were scarce and mostly occurred in southern Spain. Since then, there have been new cases every year and the pathogen has spread to new regions. Thus, monitoring of circulating variants and lineages plays a fundamental role in understanding WNV evolution, spread and dynamics. In this study, we sequenced WNV consensus genomes from mosquito pools captured in 2022 as part of a newly implemented surveillance program in southern Spain and compared it to other European, African and Spanish sequences. Characterization of WNV genomes in mosquitoes captured in 2022 reveals the co-circulation of two WNV lineage 1 variants, the one that caused the outbreak in 2020 and another variant that is closely related to variants reported in Spain in 2012, France in 2015, Italy in 2021–2022 and Senegal in 2012–2018. The geographic distribution of these variants indicates that WNV L1 dynamics in southern Europe include an alternating dominance of variants in some territories.