Understanding the flexibility of interactions and network rewiring (i.e. reassembly of interactions due to partner-switching) is necessary to comprehend how future anthropogenic changes will affect interspecific interactions and the functioning of communities. A higher rewiring could be expected in more disturbed landscapes because these landscapes contain fewer and more generalist species with more homogeneous traits. We sampled pollination interactions in 20 wild Olea europaea communities along a disturbance gradient to evaluate the hypothesis that the loss of natural habitats increases seasonal (within-year) interaction rewiring in plant-pollinator communities, influencing their functional structure. For this, we particularly tested whether rewiring frequency was negatively related to the extent of natural habitats surrounding the communities, whether interaction rewiring influenced the static structure of networks (nestedness, network specialization –H2'–), and whether a high generalization (low specialization –d'–) and abundance of species in communities made them more prone to rewiring. We show that habitat loss increased seasonal interaction rewiring in networks. Changes in rewiring were related to changes in the cumulative static structure of pollination networks. Nestedness decreased and network specialization (H2') also tended to decrease as interaction rewiring increased, suggesting an indirect effect of habitat loss on the robustness of networks through their dynamics. As expected, generalist insect and plant species were more prone to rewiring. However, flower abundance had different effects on the rewiring probability of plant species depending on the extent of habitat loss, with abundant species rewiring more in disturbed communities and rewiring less in more natural communities. Likely, this is related to the context-dependent foraging behaviour of pollinators, which may switch to more abundant species if the cost of searching for trait-matching resources is high in disturbed habitats. Our work shows the role of partner-switching in generalist species to adapt to new conditions. It also highlights the importance of going beyond general network metrics to understand the underlying processes of community-level interaction assembly and predict and anticipate the effects of anthropogenic disturbances on pollination services., This study was supported by the project CGL2017-89254-R, financed by the Spanish Ministry of Science and Innovation, FEDER Funds and the Spanish State Research Agency, and by the project PRPPID2020-117863RB-I00, financed by the Spanish Ministry of Science and Innovation and the Spanish State Research Agency (MCIN/AEI/10.13039/501100011033). A.L. was also supported by a Ramón y Cajal contract (RYC-2015-19034) from the Spanish Ministry of Science, Innovation and Universities, the Spanish State Research Agency, European Social Funds (ESF invests in your future) and the University of the Balearic Islands. C.G.M. was supported by an FPI predoctoral contract financed by the Spanish Ministry of Science, Innovation and Universities (FPI PRE2018-083185)., Peer reviewed

Loss of habitats and native species, introduction of invasive species, and changing climate regimes lead to the homogenization of landscapes and communities, affecting the availability of habitats and resources for economically important guilds, such as pollinators. Understanding how pollinators and their interactions vary along resource diversity gradients at different scales may help to determine their adaptability to the current diversity loss related to global change. We used data on 20 plant–pollinator communities along gradients of flower richness (local diversity) and landscape heterogeneity (landscape diversity) to understand how the diversity of resources at local and landscape scales affected (1) wild pollinator abundance and richness (accounting also for honey bee abundance), (2) the structure of plant–pollinator networks, (3) the proportion of actively selected interactions (those not occurring by neutral processes), and (4) pollinator diet breadth and species' specialization in networks. Wild pollinator abundance was higher overall in flower-rich and heterogeneous habitats, while wild pollinator richness increased with flower richness (more strongly for beetles and wild bees) and decreased with honeybee abundance. Network specialization (H′), modularity, and functional complementarity were all positively related to floral richness and landscape heterogeneity, indicating niche segregation as the diversity of resources increases at both scales. Flower richness also increased the proportion of actively selected interactions (especially for wild bees and flies), whereas landscape heterogeneity had a weak negative effect on this variable. Overall, network-level metrics responded to larger landscape scales than pollinator-level metrics did. Higher floral richness resulted in a wider taxonomic and functional diet for all the study guilds, while functional diet increased mainly for beetles. Despite this, specialization in networks (d′) increased with flower richness for all the study guilds, because pollinator species fed on a narrower subset of plants as communities became richer in species. Our study indicates that pollinators are able to adapt their diet to resource changes at local and landscape scales. However, resource homogenization might lead to poor and generalist pollinator communities, where functionally specialized interactions are lost. This study highlights the importance of including different scales to understand the effects of global change on pollination service through changes in resource diversity., This study was supported by the project CGL2017-89254-R financed by Feder Funds, the Spanish Ministry of Economy and Competitiveness, and the Spanish Research Agency, and the project PRPPID2020-117863RB-I00 financed by the Spanish Ministry of Science and Innovation and the Spanish Research Agency (MCIN/AEI/10.13039/501100011033). A. Lázaro was supported by a Ramón y Cajal (RYC-2015-19034) contract from the Spanish Ministry of Science, Innovation, and Universities, the Spanish State Research Agency, European Social Funds (ESF invests in your future) and the University of the Balearic Islands. C. Gómez-Martínez was supported by a FPI predoctoral contract financed by the Spanish Ministry of Economy and Competitiveness, the Spanish Research Agency, and European Social Funds (FPI PRE2018-083185, Call 2018).

The topological structure of interaction networks determines community dynamics and stability. Closeness centrality is a species-level attribute that measures the relative position and proximity of species in the interaction network. We assessed the link between closeness centrality of crops in plant-pollinator interaction networks and crop seed production. We worked with five crop species used for seed production distributed in 14 farms. At each farm we recorded pollinators’ interactions with the crop and with the co-flowering plants at crop edges and built quantitative plant-pollinator interaction networks. For each network, we calculated weighted closeness centrality of crops and related it to crop seed set by using generalized linear mixed models. Our results show that crop centrality is positively associated with crop seed production, and suggest that the use of ecological interaction network metrics in agricultural systems could be useful to design agronomic management plans and enhance crop yields., This study was supported by INTA fellowship Disp. No. 942/15, PNAPI-P.E. I017, The Rufford Foundation Small Grant (ID 29765-1), the Agencia Nacional de Promoción Científica y Tecnológica: grants PICT 2015-2523 and PICT 2017-3336, and CONICET: PIP 2020-3024CO. AL was supported by a Ramón y Cajal contract (RYC-2015-19034) from the Spanish Ministry of Science, Innovation and Universities, the Spanish State Research Agency, European Social Funds (ESF invests in your future) and the University of the Balearic Islands, and by the project PRPPID2020-117863RB-I00 financed by the Spanish Ministry of Economy and Competitiveness, Feder founds and the Spanish Research Agency., Peer reviewed

Understanding temporal dynamics in ecological networks is crucial to predict their capability to cope with global changes. Despite this, proper quantification of network dynamics still remains a challenge. Temporal dynamics are typically studied using data of interaction networks over time, through the evaluation of interaction turnover and its two components: changes related to species turnover (species gains and losses) or rewiring (switching partners among the set of species shared over time). However, with this approach based exclusively on network data, dynamics are computed similarly for species that are truly missing from the community at a given temporal period, and for species occurring in the community but that do not interact with any other. This might lead to an underestimation of the real extent of rewiring, while overestimating the species turnover component of interaction turnover. We used data on 20 plant–pollinator communities to calculate interaction turnover components accounting also for the species that occurred in the communities at different temporal periods but did not appear in some of the temporal interaction networks (non-interacting species) and then compared these estimates with conventional ones. Besides, we used empirical data and simulations to evaluate the extent to which dynamics estimates were affected by sampling effort when including and excluding non-interacting species. As expected, disregarding the non-interacting species that occurred in the communities at different temporal periods led to the underestimation of rewiring and the overestimation of species turnover as components of interaction turnover. Effect size was moderate when independent pollinator data were included, and large when including plants or both trophic levels. Simulations indicated that, in general, considering the non-interacting species reduced biases at the time of identifying changes due to the different interaction turnover components. Accounting for non-interacting species was particularly important to reduce bias when sampling effort was low and when dynamics were calculated seasonally. Despite sampling effort effects, phenology was the main determinant of species' rewiring frequencies. Our approach contributes to reducing biases and improving the estimates of interaction flexibility in networks, which are necessary to comprehend the response of communities in the face of global change., Spanish Ministry of Science and Innovation & Spanish Research Agency, Grant/Award Number: (MCIN/
AEI/10.13039/501100011033) and PID2020-117863RB-I00; Spanish Ministry of Science and Innovation, Feder Funds & Spanish Research Agency, Grant/Award Number: CGL2017-89254-R; Spanish Ministry of Economy and Competitiveness, Spanish Research Agency & European Social Funds, Grant/Award Number: FPI PRE2018- 083185; IMEDEA is an accredited “Maria de Maeztu Excellence Unit” (period 2023-2027), Grant/Award Number: CEX2021- 001198., With funding from the Spanish government through the "Severo Ochoa Centre of Excellence" accreditation (CEX2021- 001198)., Peer reviewed

Worldwide pollinator declines are a major problem for agricultural production. However, understanding how landscape characteristics and local management influence crop production through its pollinators is still a challenge. The carob tree (Ceratonia siliqua) is a pollinator-dependent Mediterranean crop of high economic importance in food and pharmaceutical industries. To understand how crop production can be enhanced in a sustainable manner, we evaluated the effects of landscape (habitat loss) and orchard local management (farming system: conventional vs. ecological; male-to-female ratio) on pollinator communities and crop production using data on 20 carob tree orchards across Mallorca Island (Spain). We found that orchards surrounded by a greater proportion of natural landcover received more visits by wild bees and butterflies and fewer by honeybees. Overall pollinator abundance was slightly higher in ecological than conventional orchards, but the difference was not significant. High male-to-female ratio enhanced overall pollinator abundance and shaped pollinator composition, by increasing hoverfly abundance and decreasing wasp and fly abundance. Male-to-female ratio showed hump-shaped relationships with fruit and seed production per female tree (peak at 0.7 males/female), although this quadratic relationship was lost when the most male-biased orchards were removed from the analyses. Total orchard production maximized with 25-30% of males. Seed weight (farmer's highest economic value) increased in conserved landscapes where wild pollinators prevailed, and with overall pollinator abundance; however, it decreased with male-to-female ratio, likely due to seed number-size trade-offs. Management strategies to enhance carob production may optimize sex ratios and favor wild pollinators by preserving natural landscapes., This study was supported by the project CGL2017-89254-R, financed by the Spanish Ministry of Science and Innovation, FEDER Funds and the Spanish State Research Agency, and by the project PRPPID2020-117863RB-I00, financed by the Spanish Ministry of Science and Innovation and the Spanish State Research Agency (MCIN/AEI/10.13039/501100011033). CGM was supported by a FPI predoctoral contract financed by the Spanish Ministry of Economy and Competitiveness, the Spanish Research Agency, and European Social Funds (FPI PRE2018-083185, Call 2018)., Peer reviewed

The transformation of natural landscapes for agricultural purposes may severely affect wild bee and wasp reproduction. In this study, we located trap-nests on 18 natural Mediterranean communities within agricultural areas to study the effects of landscape (% natural areas and heterogeneity) and local flowering communities (flower abundance and richness) on the total abundance and richness of solitary bees and wasps that nest within cavities. We also estimated several reproductive variables (number of nests, number of cells per nest, sex ratio, parasitoidism and survival) of the two most common species in the study system: the bee Osmia caerulescens and the wasp Ancistrocerus longispinosus. We found that total bee abundance increased with flower richness and landscape heterogeneity, while it decreased with flower abundance. Furthermore, our results indicated local and landscape effects on the focal species reproductive success, being stronger those at the local than at the landscape scale overall. Floral richness and abundance influenced the number of cells per nest. However, while the effect of flower abundance was positive in both cases, the effect of flower richness differed, being positive for O. caerulescens and negative for A. longispinosus. The percentage of natural habitats in the landscape had a positive additional effect on the number of cells per nest only in A. longispinosus. Besides, flower richness was positively related to the proportion of females in both species and increased O. caerulescens survival. Our findings stress the importance of considering different spatial scales for an effective conservation management that takes into account Hymenoptera reproduction., This study was supported by the project PRPPID2020-117863RB-I00, financed by the Spanish Ministry of Science and Innovation and the Spanish State Research Agency (MCIN/AEI/10.13039/501100011033). CGM was supported by a FPI predoctoral contract financed by the Spanish Ministry of Economy and Competitiveness, the Spanish Research Agency and European Social Funds (FPI PRE2018-083185, Call 2018). JPH received support from CONICET, while MLA was supported by INTA. CONICET financed the research stay of HJM at IMEDEA in 2022; the research stays of HJM, MLA and JPH at IMEDEA in 2023 were financed by the Office for Cooperation to Development and Solidarity at the University of the Balearic Islands, through the project OCDS-REC2023/02. IMEDEA is an accredited “Maria de Maeztu Excellence Unit” (Grant CEX2021-001198, funded by MCIN/AEI/10.13039/501100011033) (period 2023-2027)., With funding from the Spanish government through the "Maria de Maeztu Centre of Excellence" accreditation (CEX2021-001198)., Peer reviewed

Understanding how plant-pollinator interactions vary along disturbance gradients and influence community function is essential to comprehend how pollination services can be maintained in increasingly anthropized landscapes. Recent studies found positive relationships between plant fitness and centrality in interaction networks (i.e., high proximity to other plants via shared pollinators). However, this relationship might vary depending on communities' landscape context and species' functional traits. We hypothesized that the fitness benefits of centrality might be higher in homogeneous landscapes than in heterogeneous landscapes, as the former might favor generalist species and behaviors. We also expected stronger positive relationships between centrality and fitness in pollinator-dependent actinomorphic species compared to autogamous species that do not depend on pollinators or zygomorphic species that are pollinated by a small set of specialized species. Here, we combined field samplings and experiments to study how centrality related to fitness (seeds produced) in 11 plant species from 20 communities along a gradient of landscape heterogeneity. For that, we assessed changes in the centrality-fitness relationship associated with landscape variations and species' functional groups: autogamous species, entomophilous-actinomorphic species, and entomophilous-zygomorphic species. We found that centrality positively influenced plant fitness in more homogeneous landscapes, whereas it had a null effect on fitness in more heterogeneous landscapes. Furthermore, centrality was irrelevant for the fitness of mostly autogamous plant species but influenced the fitness of mostly entomophilous species, increasing the reproductive output in actinomorphic species while decreasing it in zygomorphic ones. For the first time, we show that the relationship between interaction structure and function varies with the landscape context and the group of species evaluated. Our study also highlights the importance of conserving heterogeneous landscapes to maintain effective specialized interactions, as the higher fitness benefits of centrality in homogeneous landscapes might drive feedback cycles of increased generalization over time in communities within these landscapes., Spanish Ministry of Science and Innovation, Feder funds, and the Spanish Research Agency, Grant/Award Number: CGL2017-89254-R; Spanish Ministry of Science and Innovation and the Spanish Research Agency (MCIN/AEI/10.13039/501100011033), Grant/Award Number:PRPPID2020-117863RB-I00; Spanish Ministry of Science, Innovation and Universities, Feder funds, and the Spanish Research Agency (MCIN/AEI /10.13039/
501100011033 and FEDER,UE),Grant/Award Number: PID2023-150295OB-I00; Spanish Ministry of Economy and Competitiveness, the Spanish Research Agency, and European Social Funds, Grant/Award Number:
PRE2018-083185, Peer reviewed

Pollination services are currently threatened by land-use changes that lead to landscape homogenization. However, the response of particular species to anthropogenic pressures is variable and, therefore, some species may perform better (winners) and others worse (losers) in the face of landscape homogenization. Our main objective was to understand which plant and pollinator species were the most vulnerable to this landscape disturbance. To evaluate this, we used data on pollinator and plant abundance in 20 study sites located along a gradient of landscape heterogeneity (i.e. diversity of land-cover layers at 500 m and 1 km radius surrounding the study sites) across Mallorca Island (western Mediterranean Basin). For 46 pollinator species (hymenopterans and dipterans) and 162 plant species, we collected functional traits (either by direct measurements or from literature) that reflect the ability of species to adapt to changing environments, and related their abundance to their traits along a gradient of landscape heterogeneity. Landscape heterogeneity influenced the study groups at different scales, affecting Diptera at a smaller scale than Hymenoptera and plants. Although the number of species was not influenced by landscape heterogeneity, the abundance of species was. An increase in landscape heterogeneity favored the abundance of social Hymenoptera compared to solitary ones. The abundance of Hymenoptera that nest in the ground or in cavities increased with landscape heterogeneity, while the abundance of builders decreased. Besides, increasing landscape heterogeneity enhanced the abundance of small and medium sized Hymenoptera, whereas the abundance of large Hymenoptera remained stable along the heterogeneity gradient. Landscape heterogeneity also favored the abundance of parasitoid and anthophilous Diptera. Regarding plants, we found that more heterogeneous landscapes also held a higher abundance of zygomorphic flowers. Understanding the ‘winners’ and ‘losers’ in the face of landscape changes may help prevent and anticipate the effects of global change on the pollination service., This study was supported by the project CGL2017-89254-R, financed by the Spanish Ministry of Science and Innovation, FEDER Funds and the Spanish State Research Agency, by the project PRPPID2020-117863RB-I00, financed by the Spanish Ministry of Science, Innovation and Universities, and the Spanish State Research Agency (MICIU/AEI/10.13039/501100011033), and by the project PID2023-150295OB-I00 financed by the Spanish Ministry of Science, Innovation and Universities and the Spanish State Research Agency. CGM was supported by a FPI predoctoral contract financed by the Spanish Ministry of Economy and Competitiveness, the Spanish Research Agency, and European Social Funds (FPI PRE2018-083185, Call 2018). IMEDEA is an accredited “Maria de Maeztu Excellence Unit” (Grant CEX2021-001198; period 2023-2027)., With funding from the Spanish government through the "Maria de Maeztu Centre of Excellence" accreditation (CEX2021-001198)., Peer reviewed

Plants with complex floral morphologies are adapted to be pollinated by restricted pollinator assemblages and may suffer pollinator limitation. Understanding how floral traits and other variables relate to plant vulnerability can provide a powerful tool for predicting the conservation status and prioritizing the assessment of plants with scarce field data. Using circa 3000 records of rare and threatened (sensu IUCN) entomophilous plant taxa from seven Mediterranean countries, we evaluated how six floral traits and other eight intrinsic and extrinsic variables were related to plant vulnerability (less vs. more threatened plants). Besides, we analyzed 29 experts' opinions regarding the floral traits most related to floral complexity. Floral shape, reproductive unit, and flowering duration were good vulnerability indicators. Taxa with lip- and flag-shaped flowers were the most threatened, which agrees with the opinion of experts who considered lip- and flag-shaped flowers to have more complex morphologies. Also, plants with cylindrical inflorescences or solitary flowers were more threatened than those with flat-spherical inflorescences; and longer flowering durations reduced the probability of being threatened. Regarding extrinsic variables, coastal and freshwater habitats, i.e. habitats heavily impacted by human activities, had the highest percentage of highly threatened taxa. Yet, plant vulnerability decreased with maximum elevation and total distribution range. These results may serve as a basis for managers and practitioners when field data are scarce or unavailable, so that, depending on their traits, species could be provisionally listed in Red Lists as deserving priority for assessment to ascertain conservation status and actions., This research was carried out in the frame of COST Action CA18201 — An Integrated Approach to Conservation of Threatened Plants for the 21st Century (ConservePlants), supported by COST (European Cooperation in Science and Technology). AS received a STSM COST grant (ECOST-STSM-Request-CA18201-47362). AL was financed by PID2020-117863RB-I00 (MCIN/AEI/10.13039/501100011033) and PID2023-150295OB-I00 projects, financed by the Spanish Ministry of Science and Innovation and the Spanish State Research Agency. JL and SC were supported by FCT - Fundação para a Ciência e a Tecnologia, I.P., in the framework of the Project UIDB/04004/2020 and DOI identifier 10.54499/UIDB/04004/2020 (https://doi.org/10.54499/UIDB/04004/2020)., Peer reviewed

The IUCN threat categories are widely used to assess the conservation status of plants and other organisms, primarily based on population size and trends vis-à-vis geographical ranges. However, other factors could also predict plant vulnerability. Here, we analysed plant traits that could be potential predictors of vulnerability for the endemic flora of the Balearic Islands (western Mediterranean Basin). We first compiled the list of entomophilous plant species endemic to the Balearic Islands and categorized their vulnerability as “threatened” (EW, CR, EN, VU) or “not threatened” (NT, LC) according to the regional Red Data Book. We then gathered bibliographic information on several variables related to flower complexity (floral traits related to pollinator specificity), flowering season, flowering duration, life form, capability of asexual reproduction, and main habitat. The endemic entomophilous flora of the Balearic Islands comprises 155 taxa, of which 57 (37%) are currently listed as threatened. Our results showed that floral colour, flowering duration and habitat type were the main predictors of vulnerability for the endemic flora of the Balearic Islands. Species with green and blue/violet/purple/pink/red flowers were more endangered than plants with white flowers, while species with yellow flowers showed intermediate levels of vulnerability. Besides, plant vulnerability was higher in plants with short flowering duration, and those inhabiting mountain and coastal habitats. These findings highlight the importance of considering additional traits when assessing extinction risk and planning conservation strategies. In particular, conservation efforts in the Balearic Islands should prioritize taxa inhabiting coastal habitats and mountain areas., Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. This work has been funded though MULTIFUN (PID2020-117863RB-I00) and FUNLAND (PID2023-150295OB-I00) projects, financed by the Spanish Ministry of Science, Innovation and Universities, and the Spanish State Research Agency (MCIN/AEI/10.13039/501100011033). MC was supported by postdoctoral grant Juan de la Cierva Formación 2021 (FJC2021-046888-I, funded by the Spanish Ministry of Science and Innovation). The research has benefited from the COST Action CA18201 — An Integrated Approach to Conservation of Threatened Plants for the 21st Century (ConservePlants), supported by COST (European Cooperation in Science and Technology). IMEDEA is an accredited “Maria de Maeztu Excellence Unit” (Grant CEX2021-001198) (period 2023–2027)., With funding from the Spanish government through the "Maria de Maeztu Centre of Excellence" accreditation (CEX2021-001198)., Peer reviewed

Plants with complex floral morphologies are adapted to be pollinated by restricted pollinator assemblages and may suffer pollinator limitation. Understanding how floral traits and other variables relate to plant vulnerability can provide a powerful tool for predicting the conservation status and prioritizing the assessment of plants with scarce field data. Using circa 3000 records of rare and threatened (sensu IUCN) entomophilous plant taxa from seven Mediterranean countries, we evaluated how six floral traits and other eight intrinsic and extrinsic variables were related to plant vulnerability (less vs. more threatened plants). Besides, we analyzed 29 experts' opinions regarding the floral traits most related to floral complexity. Floral shape, reproductive unit, and flowering duration were good vulnerability indicators. Taxa with lip- and flag-shaped flowers were the most threatened, which agrees with the opinion of experts who considered lip- and flag-shaped flowers to have more complex morphologies. Also, plants with cylindrical inflorescences or solitary flowers were more threatened than those with flat-spherical inflorescences; and longer flowering durations reduced the probability of being threatened. Regarding extrinsic variables, coastal and freshwater habitats, i.e. habitats heavily impacted by human activities, had the highest percentage of highly threatened taxa. Yet, plant vulnerability decreased with maximum elevation and total distribution range. These results may serve as a basis for managers and practitioners when field data are scarce or unavailable, so that, depending on their traits, species could be provisionally listed in Red Lists as deserving priority for assessment to ascertain conservation status and actions., European Cooperation in Science and Technology | Ref. ECOST-STSM-Request-CA18201-47362, Agencia Estatal de Investigación | Ref. PID2023-150295OB-I00, Fundação para a Ciência e a Tecnologia | Ref. UIDB/04004/2020, Agencia Estatal de Investigación | Ref. PID2020-117863RB-I00