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Decreasing the dependence on external inputs to crop yield maximization is one of the main objectives of agricultural breeding programs. For this reason, new crop varieties once highly dependent on pollinators have been developed to be self-fertile and are now cultivated as pollinator-independent. However, the contribution of pollinators to these varieties remains unknown. In this study, we evaluated pollinators’ contribution to two self-fertile almond varieties (Marta and Marinada) and the density of pollinators needed to ensure adequate pollination. We measured the effects of pollinators on fruit set, seed yield, and pollination limitation at the tree level. Managed honeybees and wild bumblebees were the main floral visitors in both varieties. Both fruit set and seed yield were ~ 50% higher in pollinated trees than in excluded ones in the two varieties. We found no evidence of pollination limitation, suggesting that pollinators’ abundance was sufficient for adequate pollination. We recommend that almond growers actively manage pollinators to maximize seed yield and profits in these self-fertile varieties.

Premise of the study: On islands, flowering plants tend to be more generalist in their pollination needs, as insects (the main pollinators of flowering plants) are underrepresented in these ecosystems compared to the mainland. In addition, some vertebrate species that are typically insectivorous or granivorous on the mainland are forced to broaden their diet and consume other resources such as nectar or pollen on the islands. The shrub Malva arborea, with its large and colourful flowers, attracts different groups of potential pollinators. This study aimed to compare the effectiveness of vertebrates versus insects in an insular population of M. arborea and to investigate its reproductive system. Methods: For three groups of taxa (insects, birds and lizards), we assessed the two components of pollination effectiveness: (i) the quantitative component (i.e. number of visits and number of flowers contacted) through direct observations of flowers; and (ii) the qualitative component (fruit and seed set, number and size of seeds and proportion of seedling emergence) through pollinator exclusion experiments. Key results: Vertebrates (birds and lizards) were quantitatively the most effective pollinators, followed by insects. However, when all three groups visited the flowers, fruit and seed set were higher than when any of them were excluded. We also found that M. arborea has hermaphrodite flowers and is able to reproduce by autogamy, although less efficiently than when pollinated by animals. Conclusions: Both vertebrates and insects play an important role in the reproduction of M. arborea. Although the plant does not need pollinators to produce seeds, its reproductive success increases when all pollinators are allowed to visit the flowers. Besides providing new information on M. arborea, these findings may help to better understand the role of different pollinator groups in the reproduction of other plant species, especially on islands where the co-occurrence of vertebrate a

Altitudinal gradients, which involve diverse biotic and abiotic variables in small-scale spaces, provide a good opportunity to investigate the local and regional patterns that influence species assemblages, including those of pollinators and the plants with which they interact him. Here, we studied the variation in butterfly assemblages and their interactions with flowering plants across different altitudes in a Mediterranean mountain system. Moreover, considering the different vegetation (i.e. grassland, forest, shrubland)at each altitudinal level (i.e. lowland, mid-mountain, high-mountain), we examined the effects of food availability on butterfly assemblages. We found butterfly richness and number of interactions between butterflies and flowering plants to be mainly influenced by the altitudinal level, with the mid-mountain region exhibiting the highest levels of both variables. Flower abundance positively correlated with butterfly richness on the lowland and high-mountain levels, while vegetation was a key factor impacting both butterfly richness and butterfly-flower interactions. Network modularity was highest at the mid-mountain level, while species specialization increased with the altitudinal levels. Species composition varied significantly across the altitudinal gradient, occurring at each specific altitudinal level and between different habitats, driven primarily by species turnover rather than a nested decline in species as altitude increases. Our findings suggest that even though topoclimate may shape species composition at a regional scale, resource availability is key to explaining the differences among habitats with similar climatic conditions. This underscores the importance of promoting and maintaining diverse food resources for butterflies, particularly in the challenging environmental conditions found at both high and low altitudinal levels in Mediterranean mountain regions. Furthermore, a multiscale approach to butterfly conservation is imperativ

[Aim] Intraspecific variation in species relative abundance is shaped by a complex interplay of abiotic and biotic factors, making it both necessary and challenging to assess their combined relative importance in explaining variations across space and time. We used two congeneric butterfly species for which extensive count data and a deep understanding of their natural history is available to test three hypotheses explaining intraspecific variation in their abundance: (H1) seasonal dispersal behaviour driven by climate, (H2) resource availability and (H3) apparent competition mediated via shared parasitoids., [Taxon] Gonepteryx rhamni (Brimstone) and G. cleopatra (Cleopatra)., [Location] NE Iberian Peninsula, where both species coexist, and a nearby archipelago (Balearic Islands), where only Cleopatra occurs., [Methods] We analysed spatial abundance variations for both species in the mainland and island–mainland differences in the abundance of Cleopatra. Abiotic and biotic factors, including temperature, host plant and overwintering habitat availability, larval parasitism and density dependence, were tested to explain the observed variations., [Results] H1 can explain variation in butterfly abundance between mainland regions since in warmer summers populations increased in cooler areas but decreased in warmer areas. H2 explains the variation within mainland climate regions with a strong positive relationship between resource availability and abundance but is unlikely to explain the island–mainland variation in the abundance of Cleopatra. H3 could neither explain biogeographical variation in abundance because although richer parasitoid communities were found on the mainland, larval mortality rates were similar or lower on the mainland than in the islands., [Main Conclusions] Climate and resource availability jointly account for variation in butterfly abundance across the mainland, but neither these factors nor parasitism can explain island–mainland differences. Both coexisting butterfly species and their larval parasitoids may have undergone evolutionary processes, resulting in spatial segregation that promotes the coexistence of the two butterfly species on the mainland.

[Aim] To analyse the role of non-frugivorous birds on seed dispersal, seed dispersal by gulls is expected to be especially instrumental in island ecosystems, as these have a smaller subset of frugivores when compared to the mainland, and because long-distance dispersal is required for plant colonisation. Here, we investigated the seed dispersal of olives by gulls among 10 islands of the same archipelago to reveal if gulls contribute to long-distance seed dispersal including different islands, and how gulls' adaptation to domestic olives and individual differences in foraging activities affect their seed dispersal pattern., [Location] Balearic Islands in the Western Mediterranean Sea, Spain., [Taxon] Yellow-legged gulls (Larus michahellis), Domestic and wild Olives (Olea europaea and O. europaea var. sylvestris)., [Methods] We developed seed dispersal models of the two ecotypes of olives dispersed by gulls across an archipelago, based on GPS tracking data, gut passage time and seed viability., [Results] Mean dispersal distances were 7.67 (±12.48) km in wild and 12.57 (±13.08) km in domestic olives. 7.1% of wild and 8.5% of domestic olives were dispersed among islands. Among these, 8.2% of domestic seeds were transported from large to small islands where gull colonies are located, whereas wild olives were dispersed in more variable directions. Such dispersal pattern of two olive ecotypes was consistent despite the differences in dispersal distances among individuals., [Main Conclusions] Gulls contributed to long-distance olive seed dispersal including different islands. The seed dispersal of domestic olives to longer distances with specific directions may facilitate colonisation and expansion of that variant if the conditions of seed deposition sites are suitable. Our findings indicate that gulls are relevant vectors for long-distance dispersal of large fleshy fruits in island ecosystems where specialist large frugivores are absent.

Agricultural intensification, afforestation and land abandonment are major drivers of biodiversity loss in semi-natural grasslands across Europe. Reversing these losses requires the reinstatement of plant–animal interactions such as pollination. Here we assessed the differences in species composition and patterns of plant-pollinator interactions in ancient and restored grasslands and how these patterns are influenced by landscape connectivity, across three European regions (Belgium, Germany and Sweden). We evaluated the differences in pollinator community assemblage, abundance and interaction network structure between 24 ancient and restored grasslands. We then assessed the effect of surrounding landscape functional connectivity (i.e. green infrastructure, GI) on these variables and tested possible consequences on the reproduction of two model plants, Lotus corniculatus and Salvia pratensis. Neither pollinator richness nor species composition differed between ancient and restored grasslands. A high turnover of interactions across grasslands was detected but was mainly due to replacement of pollinator and plant species. The impact of grassland restoration was consistent across various pollinator functional groups, whereas the surrounding GI had differential effects. Notably, bees, butterflies, beetles, and dipterans (excluding hoverflies) exhibited the most significant responses to GI variations. Interestingly, networks in restored grasslands were more specialised (i.e. less functionally redundant) than in ancient ones and also showed a higher number of insect visits to habitat-generalist plant species. Landscape connectivity had a similar effect, with habitat-specialist plant species receiving fewer visits at higher GI values. Fruit set in S. pratensis and L. corniculatus was unaffected by grassland type or GI. However, the fruit set in the specialist S. pratensis increased with the number of pollinator visits, indicating a positive correlation between pollinator ac

Despite the dynamic nature of communities, most research typically treated interaction networks as static entities, and only a few analysed the spatial and the temporal scales simultaneously. Here, we used spatial and temporal multilayer networks to explore the persistence of species and interactions in space and time, as well as the variation of species role (centrality) according to biotic factors. We further investigated, for the first time, the spatio-temporal variation in multilayer network structure. Species exhibited substantial turnover across time mainly due to differences in species phenology. In contrast, interaction turnover was more pronounced across habitats, which seems to be a common strategy of pollinators to adjust interactions spatially to different ecological scenarios. Plant species were comparatively more important to the cohesiveness of spatial than temporal networks, whereas the centrality of pollinators correlated between scales. The importance of plant species fluctuated temporally due mainly to changes in flower density, whereas that of pollinators fluctuated in space and time according to their relative abundance. Module composition was highly unstable in time. Species were highly capable of changing partners and module affiliation across both scales. We conclude that plant–pollinator interactions are highly dynamic in space and time, and that there are differences between plants and pollinators in their use of resources across habitats and subseasons with implications for the understanding of functional connectivity and multilayer structure.

Keystone species are disproportionately important for ecosystem functioning. While all species engage in multiple interaction types with other species, keystone species importance is often defined based on a single dimension of their Eltonian niche, that is, one type of interaction (e.g. keystone predator). 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 examining 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 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. Read the free Plain Language Summary for this article on the Journal blog.

Plant–lizard interactions are still poorly studied, despite lizards are known to interact with flowering plants in many parts of the world. They are commonly reported on islands although the number of documented interactions has also increased in mainland, mostly in isolated environments. In this study, we first performed a global review to explore whether lizard–flower and lizard double mutualistic interactions in continents occur in environments similar to those of islands. Then, we aimed at explaining the factors driving the current distribution of such interactions worldwide. To do this, we considered four environmental factors (latitude, altitude, rainfall and temperature), and phylogeny and body size of lizards that may influence flower visitation. Furthermore, we investigated for the first time the functional role (legitimate visit versus florivory) of lizards in plant reproduction and the conditions under which each type of interaction occurs. Finally, we explored the factors influencing the distribution of lizard double mutualisms worldwide. We recorded a total of 452 lizard–flower interactions (ca 3.4% and 0.1% of the extant lizard and plant species, respectively). Lizard–flower interactions were more frequently recorded on islands (79%) regardless of phylogeny and lizard body size, whereas in mainland the number of interactions increased with altitude. Our analyses also revealed that only 20% of all interactions confirmed pollination effectiveness and a strong association of the type of interaction with environmental factors and species traits. Regarding the distribution of lizard double mutualisms, we found a positive effect of island and rainfall, but a decrease in their occurrence with latitude, altitude, temperature and body size. We predict that mutualistic plant–lizard interactions will be increasingly documented, especially in isolated environments (both on islands and continents), which will help us to better understand the biological patterns of

Invasive plants displaying disparate pollination environments and abiotic conditions in native and non-native ranges provide ideal systems to test the role of different ecological factors driving flower colour variation. We quantified corolla reflectance of the ornithophilous South American Nicotiana glauca in native populations, where plants are pollinated by hummingbirds, and in populations from two invaded regions: South Africa, where plants are pollinated by sunbirds, and the Balearic island of Mallorca, where plants reproduce by selfing. Using visual modelling we examined how corolla reflectance could be perceived by floral visitors present in each region. Through Mantel tests we assessed a possible association between flower colour and different abiotic factors. Corolla reflectance variation (mainly along medium to long wavelengths, i.e. human green-yellow to red colours) was greater among studied regions than within them. Flower colour was more similar between South America and South Africa, which share birds as pollinators. Within invaded regions, corolla reflectance variation was lower in South Africa, where populations could not be distinguished from each other by sunbirds, than in Spain, where populations could be distinguished from each other by their occasional visitors. Differences in corolla colour among populations were partially associated with differences in temperature. Our findings suggest that shifts in flower colour of N. glauca across native and invaded ranges could be shaped by changes in both pollination environment and climatic factors. This is the first study on plant invasions considering visual perception of different pollinators and abiotic drivers of flower colour variation.

Phenological overlap between crop flowering and pollinators is a crucial trait for the pollination of more than 75% of the world's crops. However, crop management rarely considers the seasonal aspect of plant–pollinator mutualism. Here, we investigate the phenological overlap between crops and pollinators and how it affects pollination and fruit production. We measured the abundance and richness of native and non-native pollinators visiting raspberry flowers at two different times during the flowering season (i.e. early and late flowering periods) and examined their effects on crop yield in 16 fields. The community of pollinators foraging on raspberry flowers was more diverse and dominated by native pollinators during the early flowering period when most native plant species were flowering. Later in the season, when native flower resources declined in the surrounding environment, raspberry flowers were visited mainly by two non-native bees: managed honeybees and the invasive bumblebee Bombus terrestris. Pollinator contribution to raspberry yield was twice as high in the early flowering period compared to the late period (61% vs. 31% increase in drupelet set respectively). Flower damage caused by extremely high visitation frequencies by non-native bees in the late period was six times higher than in the early flowering period (30% vs. 5% of damaged flowers respectively). Synthesis and applications. Providing sufficient pollen and nectar resources to support wild pollinators over extended periods in agricultural landscapes can contribute to crop pollination and ensure high fruit weight and quality. This can be achieved by restoring natural and semi-natural areas near crop fields with native, long-flowering plant species. Growers and crop breeding programmes should consider selecting flowering times that coincide with periods of high diversity or abundance of native pollinators to reduce dependence on managed pollinators.

Pollinators mediate interspecific and intraspecific plant-plant indirect interactions (competition vs. facilitation) via density-dependent processes, potentially shaping the dynamics of plant communities. However, it is still unclear which ecological drivers regulate density-dependent patterns, including scale, pollination niches (i.e., the main pollinator functional group) and floral attractiveness to pollinators. In this study, we conducted three-year field observations in Hengduan Mountains of southwest China. By gathering data for more than 100 animal-pollinated plant species, we quantified the effect (positive vs. negative) of conspecific and heterospecific flower density on pollination at two scales: plot-level (4 m2) and site-level (100-5000 m2). Then, we investigated how pollination niches and floral attractiveness to pollinators (estimated here as average per-flower visitation rates) modulated density-dependent pollination interactions. Pollinator visitation depended on conspecific and heterospecific flower density, with rare plants subjected to interspecific competition at the plot-level and interspecific facilitation at the site-level. Such interspecific competition at the plot-level was stronger for plants pollinated by diverse insects, while interspecific facilitation at the site-level was stronger for bee-pollinated plants. Moreover, we also found stronger positive conspecific density-dependence for plants with lower floral attractiveness at the site-level, meaning that they become more frequently visited when abundant. Our study indicates that the role of pollination in maintaining rare plants and plant diversity depends on the balance of density-dependent processes in species-rich communities. We show here that such balance is modulated by scale, pollination niches and floral attractiveness to pollinators, indicating the context-dependency of diversity maintenance mechanisms.

Although it is well recognized that the strength of plant-herbivore interactions can vary with plant sex and the distance and density of conspecific neighbors, no study has yet assessed their combined influence. Here, we filled this knowledge gap by focusing on the dioecious palm Chamaerops humilis L., and its two main herbivores, the invasive moth Paysandisia archon Burmeister and the feral goat Capra hircus L. We evaluated levels and spatial patterns of herbivory, as well as those of plant size and the number of inflorescences in two palm populations in Mallorca (Balearic Islands, Spain). Our spatial point pattern analyses revealed that palms not affected by moth herbivory or goat florivory were spatially aggregated, goats fed more strongly upon inflorescences in palms with more neighbors but they consumed more leaves in isolated palms. Interestingly, we could reveal for the first time that plant sex is a key plant trait modulating neighborhood effects. For instance, whereas aggregated female palms experienced lower intensity of goat florivory than isolated ones, male palms showed the opposite pattern. Palm size and the number of inflorescences also showed sex-related differences, suggesting that sexual dimorphism is a key driver of the observed neighborhood effects on herbivory. Our study highlights the importance of considering relevant plant traits such as sex when investigating plant neighborhood effects, calling for further research to fully understand the dynamics governing plant-herbivore interactions in dioecious systems.

Fluvial system deposits often form suitable reservoirs for CO geological storage (CGS). These potential storage sites usually present heterogeneous fluvial architectures at multiple scales. This heterogeneity can exert varied effects on different aspects of CGS, resulting in significant storage efficiency variability. Here, we investigate the effects of variable fluvial lithofacies associations on CO storage, using the Puig-reig anticline in the SE Pyrenees (Spain) as a reservoir analog. To test this, we employ a multidisciplinary approach that integrates field sedimentology, reservoir modeling, and numerical simulation of CO injection to produce models akin to different fluvial lithofacies associations. The storage volume and injectivity of CO are found to decrease in reservoirs with decreasing fractions and sizes of high-permeable facies from the proximal to the medial-distal lithofacies associations. The flow barriers created by low-permeable facies can hinder the vertical migration of the CO plume and prevent it from reaching the reservoir top, hence reducing the direct contact between the CO plume and the overlying caprock. Furthermore, an optimal amount of low-permeable layers (around 30% in this study) can increase the swept area of CO and reduce the proportions of free CO phase. These aspects can collectively increase the amount of permanently trapped CO and reduce the leakage risks of the injected CO. Based on the characteristics of the resulting models (i.e., storage volume, injectivity, distribution and phases of CO), a multi-criteria decision-making method has been used to quantitatively rank the different lithofacies associations according to their suitability for CO storage. In this analysis, the proximal-medial fluvial lithofacies associations are assessed to be the most suitable ones because they feature low proportions of the injected CO reaching the reservoir top and in free phase while maintaining the high storage volume and injectivity. This stud