Biology subjects

Timoteo, S.

Publications and source records attributed to Timoteo, S..

4 recordsLinked to original sources

bioRxiv2026

Indigenous generalist pollinators shape plant-insect interaction networks across a land-use gradient on an oceanic island

1. The study asks how plant-pollinator networks reorganise along a land-use gradient spanning five habitat types, ranging from native forests to intensively managed pastures, on the oceanic island of Terceira (Azores, Portugal). 2. Interaction dissimilarity between habitats was always very high (on average 87%) and this reshuffling was driven mainly by plant species turnover rather than insect turnover or partner rewiring. 3. Plant composition shifted strongly along the gradient, with introduced species increasingly dominating disturbed habitats, whereas pollinator richness and identity remained comparatively stable, consistent with more homogeneous communities dominated by widespread generalist indigenous insect species. 4. Connectance and nestedness were lowest, while modularity was highest, in intermediate habitats (naturalized vegetation, exotic forest) a pattern interpreted as the signature of mixed native and introduced floristic pools generating distinct modules, reinforced by locally selective insect foraging. 5. By identifying the species role in the landscape, nearly half of the flower-visiting insects was found to act as habitat connectors linking networks across the gradient. These connectors were mostly indigenous species that behaved as context-dependent generalists, switching plant partners between habitats rather than tracking the same resource everywhere. 6. Widespread pollinators with broad feeding spectra mediated the integration of introduced plants into local pollination networks. This highlights the key role of indigenous super-generalist pollinators in maintaining network resilience across the disturbance gradient. Nevertheless, the reliance on a few super-generalist species for pollination across diverse habitat-types, as reported from several archipelagos worldwide, pinpoints the vulnerability of these ecosystems to pollinator declines.

ecology↗

bioRxiv2021

Global and regional ecological boundaries drive abrupt changes in avian frugivory interactions

Species interactions can propagate disturbances across space, though ecological and biogeographic boundaries may limit this spread. We tested whether large-scale ecological boundaries (ecoregions and biomes) and human disturbance gradients increase dissimilarity among ecological networks, while accounting for background spatial and elevational effects and differences in network sampling. We assessed network dissimilarity patterns over a broad spatial scale, using 196 quantitative avian frugivory networks (encompassing 1,496 plant and 1,003 bird species) distributed across 67 ecoregions and 11 biomes. Dissimilarity in species and interactions, but not in network structure, increased significantly across ecoregion and biome boundaries and along human disturbance gradients. Our findings suggest that ecological boundaries contribute to maintaining the worlds biodiversity of interactions and mitigating the propagation of disturbances at large spatial scales. One-Sentence SummaryEcoregions and biomes delineate the large-scale distribution of plant-frugivore interactions.

ecology↗

bioRxiv2021

Tripartite networks show that keystone species can multitask

Keystone species are disproportionately important for ecosystem functioning (1,2). However, while all species engage in multiple interaction types with other species, the importance of keystone species is often defined based on a single dimension of their Eltonian niche (3), that is, one type of interaction (e.g., keystone predator). Therefore, it remains unclear whether the importance of keystone species is unidimensional or if it extends across interaction types. We conducted a meta-analysis of tripartite interaction networks to examine whether species importance in one dimension of their niche is mirrored in other niche dimensions, and whether this is associated with interaction outcome, intimacy, or species richness. We show that keystone species importance is positively associated across multiple ecological niche dimensions, independently of species abundance, and find no evidence that multidimensionality of keystone species is influenced by the explanatory variables. We propose that the role of keystone species extends across multiple ecological niche dimensions, with important implications for ecosystem resilience and conservation. Significance StatementKeystone species are often identified by focusing on a single type of interaction (e.g., predation, pollination, herbivory) which contrasts with the multiple roles that species play in biological communities. We conducted a meta-analysis of 18 tripartite interaction networks to explore if keystonness is correlated across the multiple dimensions of species Eltonian niches. Our results suggest that species importance tends to span across multiple interaction types, independently from abundance, which can be key to understand community resilience and collapse in face of multiple threats.

ecology↗

bioRxiv2018

Species activity promote the stability of fruit-frugivore interactions across a five-year multilayer network

Although biological communities are intrinsically dynamic, with both, species and interactions changing over time, interaction networks analyses to date are still largely static. We implemented a temporal multilayer network approach to explore the changes on species roles and on the emergent structure of a seed-dispersal network over five years. Network topology was relatively constant, with four well defined interaction modules spanning across all years. Importantly, species that were present on more years, were also disproportionally important on each year, thus forming a core of temporally reliable species that are critical to the cohesiveness of the multilayer network structure. We propose a new descriptor termed species activity that reflects the number of temporal, spatial or functional layers (e.g., different years, habitats, or functions) that each species integrates, providing a simple and powerful index of species importance for multilayer network cohesion.

ecology↗