Key Factors behind the Dynamic Stability of Pairs of Egyptian Vultures in Continental Spain.

Conservation science aims to identify the factors influencing the distribution of threatened species, thereby permitting the implementation of effective management strategies. This is key for long-lived species that require long-term monitoring such as the worldwide endangered Egyptian vulture (Neophron percnopterus). We studied temporal and spatial variations in the distribution of breeding pairs and examined the intrinsic and anthropic factors that may be influencing the abundance of breeding territories in continental Spain. Based on the census data of breeding pairs from 2000, 2008, and 2018, we used Rank Occupancy-Abundance Profiles to assess the temporal stability of the population and identified the spatial heterogeneity through a Local Index of Spatial Autocorrelation analysis. The GLMs showed that the abundance distribution was mainly influenced by the abundance of griffon vultures (Gyps fulvus) and cattle at a regional scale. Nonparametric comparisons showed that the presence of wind farms had a significant negative effect on local breeding pairs abundance, but that supplementary feeding stations and food resource-related variables had a positive impact. In light of these findings, we recommend a hierarchical approach in future conservation programs involving actions promoting regional-scale food resource availability and highlight the need to address the negative impact of wind farms at local levels.

Processes shaping gut microbiota diversity in allopatric populations of the endemic lizard Podarcis lilfordi from Menorcan islets (Balearic Islands).

Compositional variation of the gut microbiota across host allopatric populations can reflect both adaptation and stochasticity since the time of separation. Major factors shaping this variation include the host phylogeographic and demographic history, the microbiota inheritance, environmental inputs and dispersal of bacteria. Here we explored the impact of these factors in driving gut community diversity in seven allopatric populations of the omnivorous lizard Podarcis lilfordi from the Menorcan coastal islets, all descending from an ancestral mainland population. Using 16S rRNA Illumina sequencing, we showed that 'islet' and 'age' (time since islet separation from mainland) were the only significant variables in microbial community clustering, suggesting a partial islet-restricted diversification following these lizards phylogeography. Despite a significant variation, islets/populations were characterized by a remarkably low bacterial uniqueness (2.4% of total OTUs) and a minor differential enrichment of taxa, indicating a negligible impact of local inputs and important host common constraints. Overall, the extant pattern of similarity/dissimilarity among islets is compatible with partial retention of the ancestral mainland microbial pool, with differences among islets potentially explained by a differential loss of bacteria following population fragmentation and bottlenecks (i.e. ecological drift). While more quantitative data are needed to validate this hypothesis, this study unveils the importance of considering both neutral and niche-driven processes in driving contemporary patterns of gut metacommunity diversity.

Convergence of gut microbiotas in the adaptive radiations of African cichlid fishes.

Ecoevolutionary dynamics of the gut microbiota at the macroscale level, that is, in across-species comparisons, are largely driven by ecological variables and host genotype. The repeated explosive radiations of African cichlid fishes in distinct lakes, following a dietary diversification in a context of reduced genetic diversity, provide a natural setup to explore convergence, divergence and repeatability in patterns of microbiota dynamics as a function of the host diet, phylogeny and environment. Here we characterized by 16S rRNA amplicon sequencing the gut microbiota of 29 cichlid species from two distinct lakes/radiations (Tanganyika and Barombi Mbo) and across a broad dietary and phylogenetic range. Within each lake, a significant deviation between a carnivorous and herbivorous lifestyle was found. Herbivore species were characterized by an increased bacterial taxonomic and functional diversity and converged in key compositional and functional community aspects. Despite a significant lake effect on the microbiota structure, this process has occurred with remarkable parallels in the two lakes. A metabolic signature most likely explains this trend, as indicated by a significant enrichment in herbivores/omnivores of bacterial taxa and functions associated with fiber degradation and detoxification of plant chemical compounds. Overall, compositional and functional aspects of the gut microbiota individually and altogether validate and predict main cichlid dietary habits, suggesting a fundamental role of gut bacteria in cichlid niche expansion and adaptation.

Recent benthic foraminiferal assemblages and their relationship to environmental variables on the shoreface and inner shelf off Valencia (western Mediterranean).

The environmental variables that determine the distributions of benthic foraminiferal assemblages on the shoreface and inner shelf of the north of Valencia province (Western Mediterranean) are identified. The possible influence of variables such as water depth, distance from shore, hydrodynamics, substrate type, carbonate content, organic matter content and human activity is evaluated. Multivariate cluster-Q-type analysis and redundancy analysis (RDA) are used to identify the environmental variables that have the greatest influence on the assemblage distribution. The spatial distribution of the assemblages is closely associated with water depth and substrate. The diversity and abundance of foraminifera shells increase with depth and their conservation improves. The most common species in the study area are Ammonia beccarii, Rosalina globularis, Buccella granulata, Planorbulina mediterranensis, and Lobatula lobatula. The presence of wastewater in the study area has not polluted the foraminiferal assemblages (absence of anomalous shells). The direction of the discharge plume is a potential source of nutrients for deep water.