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Traveset, A.

Publications and source records attributed to Traveset, A..

8 recordsLinked to original sources

Seasonal variation mediates the importance of species attributes in plant-pollinator interactions

Predicting species interactions remains a major challenge, as multiple species attributes operate simultaneously and their relative importance may vary seasonally and with temporal resolution. Here, we assess how the relative contributions of abundance, trait matching, and phenology to plant-pollinator interactions vary through a flowering season and across temporal resolutions using interaction data from three European botanical gardens. We show that predictive models explain a substantial proportion of variation in visitation patterns, with floral and pollinator abundances consistently explaining most variation across the flowering season. Trait matching between pollinator body size and floral size also contributes to visitation patterns, playing a secondary but persistent role in shaping interactions, while phenology plays a relatively minor role at broader temporal resolutions but becomes more important at finer temporal scales. Additionally, null models accounting for spatio-temporal variation in floral and pollinator abundance reveal consistent patterns of pollinator preference and avoidance, indicating that abundance alone cannot explain the observed interaction patterns. Our results show that seasonal variation and temporal resolution differentially shape the importance of species attributes, highlighting the need for multi-variable approaches that account for temporal dynamics to accurately explain and predict ecological interactions.

ecology↗

Impacts of species introductions on the trait diversity of interacting avian frugivores and fleshy-fruited plants depend on native trait diversity

O_LIIntroductions of non-native species to native ecological communities by humans are major drivers of global biodiversity change. At the same time, biotic interactions, such as those between avian frugivores and fleshy-fruited plants, build the backbone of ecosystems. Hence, studying how species introductions influence interacting species of both trophic levels is essential to understand possible functional consequences of global change. C_LIO_LIHere, we take a trait-based approach, focusing on species traits that influence their biotic interactions and related ecosystem functioning, and explore how species introductions affect the diversity of such functional traits within and across assemblages of interacting fleshy-fruited plants and frugivorous birds at several locations across the globe. C_LIO_LISpecifically, we calculate differences in trait diversity and mean trait values, and compare beta trait diversity with and without introduced species, for 25 frugivorous bird and 62 fleshy-fruited plant assemblages. C_LIO_LIIntroduced species tended to increase bird and plant trait diversity in assemblages with low native trait diversity but decreased it in assemblages with higher native trait diversity. In bird assemblages, species introductions shifted mean values towards larger birds with wider bills and more pointed wings. In plant assemblages, mean trait values showed variable changes: fruit length increased and plant height decreased. C_LIO_LIComparisons between assemblages revealed that introduced species reduced the beta trait diversity of both frugivorous birds and fleshy-fruited plants, suggesting biotic homogenisation in terms of their functional traits. C_LIO_LIChanges in trait diversity underscore that species introductions can have functional consequences for biotic interactions and related ecosystem functions, potentially affecting the availability of interaction partners with matching traits and the provisioning of seed dispersal. C_LI

ecology↗

The architecture of multifunctional ecological networks

Understanding how biotic interactions affect ecosystem functioning has been a research priority in natural sciences due to their critical role in bolstering ecological resilience1-3. Yet, traditional assessment of ecological complexity typically focus on species-species effective interactions that mediate a particular function (e.g. pollination4 or seed dispersal5), overlooking the synergistic effect of multiple functions that further underpin species-function and function-function interactions in multifunctional ecosystems. At the same time, while ecological network theory holds a potential to quantify the relationship between biodiversity and ecosystem multifunctionality6, 7, its connection has been done mainly conceptually, due to challenges measuring different interactions and establishing their relevance across multiple niche dimensions8, 9. Such lack of quantitative studies therefore limits our ability to determine which species and interactions are important to maintain the multiple functions of ecosystems10. Here we develop a framework -derived from a resource-consumer-function tensor analysis-that bridges these gaps by framing biodiversity-ecosystem multifunctionality in terms of multilayer ecological network theory. Its application to recently collected ecological data -- reporting weighted interactions between plants, animals and fungi across multiple function types--allows to (i) unveil and quantify the existence of both (multi-functional) keystone species and a dual function keystoneness pattern, and (ii) project plants and functions into a similarity space where clear clusters emerge and the importance of weak links is manifested. This dual insight from species and functional perspectives will better guide conservation efforts to reduce biodiversity loss.

ecology↗

Spatial variation in relative abundances of two butterfly species sharing both host plant and natural enemies

The decline of insect populations is of great concern because they play an essential part in several services that are key for ecosystem functioning and human well-being. Therefore, full understanding of the processes and factors shaping spatial variation in insects is required for their effective conservation. Here, we study a system comprising two congeneric butterfly species (Brimstone Gonepteryx rhamni and Cleopatra G. cleopatra) that share both host plants and natural enemies and analyse whether biotic and/or abiotic factors explain their relative abundances. The two species coexist in continental Spain but not on a nearby archipelago, where only the Cleopatra occurs. The hypotheses tested were based on (H1) dispersal behaviour; (H2) apparent competition mediated via shared parasitoids; and (H3) environmental conditions (overwintering habitat availability, abundance of host plants and temperature). H1 explained differences in Brimstone abundance between climate regions on the mainland since in warmer summers populations increased in cooler areas but decreased in warmer areas. Cleopatra did not show the same pattern but was found to have twice the number of summer adults on one island than on the mainland. It is unlikely that H2 can explain this result because, although richer parasitoid communities were found on the mainland, larval mortality rates were similar. H3 was important in explaining variation in abundances between sites within each climate region even though similar environmental conditions were found on the mainland and on the islands. Our study demonstrates the complexity of any attempt to understand insect population dynamics in space due to the number of factors that are potentially involved. We argue thus that a more comprehensive approach taking into account landscape topography and resource connectivity on a broader scale is required to unravel the factors shaping the relative abundance of insects in island systems.

ecology↗

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↗

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↗

Spatio-temporal responses of butterflies to global warming on a Mediterranean island over two decades

In recent decades, efforts have been made to understand how global warming affects biodiversity and in this regard butterflies have emerged as a model group. The most conspicuous sign that warming is affecting the ecology of butterflies are the phenological advances occurring in many species. Moreover, rising temperatures are having a notable impact - both negative and positive - on population abundances. To date, patterns have generally been analysed at species level without taking into account possible differences between populations, which, when they are noted, are mostly attributed to large-scale climate differences across a latitudinal gradient. In this work, we use a long-term database of butterflies from the island of Menorca (Balearic Islands, Spain) to investigate how phenology and population dynamics have been affected by climate warming during the past two decades. In addition, we assess how responses are modulated by habitat characteristics and by species biological cycles. Our results show that species respond differently to warming at a local scale depending on season and habitat, and that coastal habitats in the Mediterranean region are particularly sensitive to the effects of climate change. Furthermore, our findings suggest that the effects of temperature could be partially offset in more inland habitats such as forests and deep ravines. The positive effect of temperature on ravine populations during the summer suggests that butterflies disperse across habitats as a response to rising temperatures during the season. This type of dispersal behaviour as a response to warming could be especially important in island ecosystems where the possibilities of modifying altitudinal or latitudinal distributions are often severely limited.

ecology↗

Determining the Minimal Background Area for Species Distribution Models: MinBAR Package

O_LIOne of the crucial choices when modelling species distributions using pseudo-absences approaches is the delineation of the background area to fit the model. We hypothesise that there is a minimum background area around the centre of the species distribution that characterizes well enough the range of environmental conditions needed by the species to survive. Thus, fitting the model within this area should be the optimal solution in terms of both quality of the model and execution time.\nC_LIO_LIMinBAR is an R package that calculates the optimal background area. The version 1.0.0 is implemented for MaxEnt and uses Boyce Index as a metric to assess models performance.\nC_LIO_LITwo case studies are presented to assess the hypothesis and to illustrate the package.\nC_LIO_LIPartial models trained with part of the species distribution often perform better than those fitted on the entire extension. MinBAR is a versatile tool that helps modellers to objectively define the optimal solution.\nC_LI

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