Biology subjects

Bellisario, B.

Publications and source records attributed to Bellisario, B..

5 recordsLinked to original sources

bioRxiv2025

The fingerprint of functional strategies in Mediterranean seagrass fish assemblages

In the Mediterranean Sea, fish assemblages associated with seagrasses host a relevant percentage of the total fish biodiversity. While the structural complexity, coverage and distribution of seagrasses are known to influence species richness and abundance, their effect on the functional composition of faunal assemblages is still unclear. Moreover, little is known about the relationships of fish specific feeding, behavioural and reproductive strategies with the potential use of this habitat during different life stages. We characterized the functional structure of fish assemblages in three main Mediterranean seagrasses, using specific functional traits known to be associated with the potential use of meadows (e.g., as nursery, refuge and/or foraging areas). We also hypothesized that given combinations of traits could be associated with the probability of species being observed on seagrasses during well-defined life stages, thereby linking different strategies to habitat use. Fish functional assemblages are non-random structured, independently of either seagrass, taxonomic composition or species diversity, suggesting a convergence in their functional structures. Mediterranean seagrasses host a core of functionally similar fish species characterized by r-like reproductive strategies and low-to-intermediate trophic levels, although differing in the range of traits exhibited by predator fauna. Moreover, unique combinations of traits are significantly associated with the likelihood of fish being observed on seagrass during specific life stages. Our findings reinforce the view that the predominant use of seagrasses by fish may be driven by a trade-off between different life-history and feeding strategies. As functional strategies are largely involved in the structuring of food webs and species recruitment, their characterization in seagrass-associated fish assemblages would enhance our understanding of the impact of multiple threats on marine biodiversity.

ecology↗

bioRxiv2023

A review of fish diversity in Mediterranean seagrass habitats, with a focus on functional traits

Seagrass habitats are considered essential in supporting both fish diversity and fisheries income. Within the Mediterranean Sea most fish species are associated to seagrasses and constitute the subject of extensive literature. However, a complete synthesis of fish species observed in different seagrass habitats is still lacking at the whole-basin Mediterranean scale, so hindering a thorough understanding of the main functional traits and mechanisms involved in determining fish diversity patterns. We performed a systematic review by implementing a semi-automated, threshold-based filtering pipeline that allowed building up a dataset concerning all fish species reported in native Mediterranean seagrasses, including specific functional traits known to be involved with the potential use of seagrasses by fish. These data allowed to carry on a narrative synthesis on fish diversity in seagrass habitats. Moreover, the functional traits analysis highlighted a significant role of trophic level, size and benthic domain in determining the distribution of fish in different seagrass habitats at whole Mediterranean basin scale. Data evidenced a pattern of segregation between large piscivorous, pelagic predators and smaller benthic prey (including juveniles) with omnivorous to herbivorous feeding habit, with aggressive predators significantly associated with Posidonia oceanica and Cymodocea nodosa beds while their putative prey tend to occupy other seagrass habitats. We identified unexpected knowledge gaps on the role of habitat heterogeneity and fish life stages in determining the presence/absence of fish in different seagrasses, for which in-depth research is needed to fully understand the links between nursery habitats and the state of exploited fish stock.

ecology↗

bioRxiv2022

Sex differences in migration timing influence the network structure of avian assemblages at a stopover site

Migratory species are changing the timing of departures from wintering areas and arrival to breeding sites (i.e., migration phenology), as response to climate change to exploit maximum food availability at higher latitudes and improve their fitness. Despite the impact of changing migration phenology on migratory connectivity at population and community level, the extent to which such individual and species-specific response affects associations among co-migrating species has been seldom explored. By applying temporal co-occurrence network models on 15 years of standardized bird ringing data at a spring stopover site, we show that African-European migratory landbirds tend to migrate in well-defined groups of species with high temporal overlap. Such co-migration fidelity is significantly increasing over the years and higher in trans-Saharan than North-African migrants. Our findings suggest non-random patterns of associations in co-migrating species, possibly related to the existence of regulatory mechanisms associated with changing climate conditions and different uses of stopover sites by migrants, ultimately influencing the global migration economy of landbirds in the Palearctic-African migration system.

ecology↗

bioRxiv2021

The spatial network structure of intertidal meiofaunal communities derived from environmental DNA metabarcoding surveys in Northwest Iberia

The identification of the patterns and mechanisms behind species distribution is one of the major challenges in ecology, having also important outcomes for the conservation and management of ecosystems. This is especially true for those components of biodiversity providing essential ecosystem functions and for which standard surveys may underestimate their real taxonomic diversity due to their high degree of cryptic diversity and inherent diagnosis difficulties, such as meiofaunal communities. Environmental DNA (eDNA) metabarcoding may provide a fast and reliable way to refine and scale-up the characterization of biological diversity in complex environmental samples, allowing to bypass such drawbacks and increase the resolution of biodiversity estimates. Moreover, the possibility of integrating eDNA metabarcoding-derived data with tools and methods rooted in network theory would deepen the knowledge of the structuring processes of ecological communities in ways that cannot be predicted from studying individual species/communities in isolation. Here, a sediment eDNA metabarcoding of mitochondrial cytochrome c oxidase I (COI) and the nuclear hypervariable V4 region of the 18S rDNA (18S) was used to reconstruct the spatial networks of intertidal meiofaunal OTUs from three estuaries of North-Western Iberian Peninsula. Null models were used to identify the role of environmental and spatial constraints on the structure of COI- and 18S-derived spatial networks and to characterize the macroecological features of surveyed phyla. Our results show the feasibility of eDNA metabarcoding, not only to capture a fair amount of diversity hard to detect with standard surveys procedures, but also to identify hierarchical spatial structures in intertidal meiofaunal assemblages. This suggests that exclusivity of occurrence rather than pervasiveness appears to be the norm in meiofaunal organisms and that niche-based processes predominantly drive the spatial aggregation and contemporary distribution of meiofaunal phyla within the system.

ecology↗

bioRxiv2020

Parallel assemblage structures in Mediterranean marine amphipods revealed by beta diversity partitioning

Relying on a purely taxonomic view of diversity may ignore the fact that ecological communities can be constituted of species having both distinct evolutionary histories and functional characteristics. Thus, considering how the multiple facets of diversity vary along environmental and geographic gradients may provide insights into the role of historic processes and current environmental conditions in determining the distribution of species, lineages and functions across space. By using distributional, taxonomic-distance and traits information, we explore the role of spatial/environmental gradients and of biogeographic subdivision of Mediterranean Sea on the different facets of beta diversity components in seagrass amphipods. Beta diversity partitioning and correlation analyses showed a nearly equal contribution of the replacement and richness components on total beta diversity for all facets, although the influence of environmental and geographic distance differs among components. While the replacement was mainly related to a pure spatial gradient, both the environmental and geographic distance were correlated with the richness component of beta diversities. Our results are in line with the complex paleobiogeographic history of the Mediterranean Sea, with the replacement component likely to be related to the progressive substitution of species of Atlantic origin with Mediterranean endemics along the west-east geographic gradient, and the richness component to the marked environmental difference between different basins. Moreover, the influence of biogeographic partition on the richness components suggests the role of spatially structured gradients at biogeographic level in determining the net loss/gain of species, lineages and functions, possibly influencing the assembly processes of passive dispersal organisms.

ecology↗