Basic and Applied Ecology

Road verges can provide important habitats for plants, especially in transformed landscapes. However, roads and their associated traffic have several adverse impacts on ecosystems that can disrupt vital ecological processes, including pollination. In transformed landscapes, road effects on pollination might be complemented by impacts of large-scale habitat modification. In these landscapes, road verge populations of plants that rely on pollinators for pollen transfer could thus be at risk of pollination failure. This study investigates the pollination of a reseeding, bird-pollinated shrub, Erica glandulosa, in road verges of a fragmented and transformed rural landscape in the southeastern Cape Floristic Region. We test for road impacts on pollination by comparing number of ruptured anther rings--a proxy for pollination--in fynbos vegetation fragments at different distances from the road (0-10, 20-30 and 40-50 m). We also test whether different land-cover types (intact fynbos, alien thickets and rangelands/pastures) next to road verges influence the number of ruptured anther rings. After controlling for robbing rate and plant density, fewer flowers were pollinated near the road than farther away, and fewer flowers were pollinated where road verges occurred next to alien thickets or pastures/rangelands compared to intact fynbos. However, bird pollination was not excluded in road verges: on average, ca. 20-30% of flowers were still visited by birds near the road. These findings potentially call into question the suitability of road verges as refugia for seed-dependent, bird-pollinated plant species in transformed landscapes.

AimsDistributions of mycorrhizal guilds correlate with differences in soil nutrient availability and tend to predominate ecosystems where plant growth and development are limited by either soil phosphorus (AM, arbuscular mycorrhiza) or nitrogen (EM, ectomycorrhiza) (Read, 1991). In an effort to characterize functional trait differences, we designed a common garden greenhouse experiment to measure growth and colonization responses between two tree seedling species (Acer rubrum and Quercus rubra) that associate with the two major mycorrhizal guilds. MethodsIn a fully factorial, 12-week greenhouse common garden experiment, seedlings were treated to three levels of nitrogen and phosphorus availability, and grown under inter- and intra-species competition. Change in heights and stem diameters were tracked and mycorrhizal colonization was quantified by percent of total and morphology. ResultsRelative growth rates were higher for Acer rubrum seedlings across treatments and intra-species competition had a strong negative effect on height and stem diameter, especially for Quercus rubra. Both species were highly colonized (>50%) by typically endomycorrhizal forms (arbuscules and vesicles) but varied in the distribution of morphological forms present in cells. ConclusionsThis study highlights the plasticity of tree seedling symbiosis during early developmental stages and challenges the strict static categorization of plant species associations with particular mycorrhizal guilds.

AimClimate warming, human modification, and global connectivity are eroding the abiotic barriers (i.e. climatic filtering and low propagule pressure) that have traditionally limited the spread of non-native species in mountain ecosystems. Meanwhile, these global changes are reshaping native plant communities, potentially weakening their biotic resistance to invasion. Yet, the role of native community resistance in modulating the upslope spread of non-native species remains overlooked, potentially masking indirect effects of global change in mountain ecosystems. LocationCentral Apennines Mountain range, Italy MethodsFollowing the Mountain Invasion Research Network (MIREN) protocol, we surveyed vegetation close and far from roads at 60 sites along three mountain roads in the Central Apennines. Using current and historical climatic data and aerial images from the 1950s to today, we quantified climate and land-use changes. Dominant plant traits and functional diversity were used to capture the biotic resistance of native communities. We then applied structural equation modelling to investigate how native biotic resistance regulates the effect of global change drivers, i.e. road disturbance and changes in land-use and climate, on the occurrence and cover of non-native species. ResultsVariance partitioning suggests that, beside climatic filtering, the biotic resistance of native communities is among the strongest drivers of non-native species occurrence and abundance. Although climate and land-use changes have had little direct influence on non-natives, land-use changes occurred over the past 70 years indirectly influenced invasions by altering native community resistance. Agricultural abandonment at low- to middle elevations, favoured short-statured native communities, offering low resistance. In contrast, forest expansion strengthened resistance through dominance of conservative native species. Main conclusionNative community resistance, alongside climate and disturbance, is a key determinant of invasion patterns along elevational gradients in Mediterranean mountains. Despite global changes facilitate non-native plant upward shifts, native communities can modulate this spread and may still maintain a certain resistance to invasion.

Plant-plant competition is ubiquitous in nature. However, studying below ground behaviour of roots has always posed certain difficulties. Pea (Pisum sativum L.) has become a sort of model species for ecological studies about how plant roots respond to neighbouring plant roots and barriers in soil. However, published results point in several different directions. This has sometimes been interpreted as pea having sophisticated context dependent responses that can change in complex ways depending on its surroundings. To explore this further, here, we combine the result of five new experiments with published results to examine 18 unique experiments from 7 different studies for a total of 254 replicates. We used a Bayesian hierarchical meta-analysis approach to estimating the likely effect size from the available data, as well as quantify heterogeneity among different experiments, studies and cultivars. The posterior distributions show that, at the coarsest possible scale of total root production, it is unlikely that P. sativum root growth is influenced by either neighbours or barriers to root growth imposed by the walls of pots that vary in volume. We suggest that further work should consider repeating experiments that reported finer scale root plasticity in pea at the rhizosphere scale, and also consider alternative model species for the study of plant root responses to external cues.

Semi-natural habitat complexity and organic management could affect the abundance and diversity of natural enemies and pollinators in olive orchards. Nonetheless, in such agroecosystems the effect of plant structure, plant richness, and plant attraction on the arthropod fauna has been poorly documented. Here we evaluate the influence of those effects jointly as an expression of arthropod abundance and richness in olive trees, ground cover, and adjacent vegetation within organic olive orchards. For this, we used generalized linear models and non-metric multidimensional scaling (NMDS) integrating generalized additive models. Our results suggest that natural enemies and pollinators are mainly attracted to A. radiatus, D. catholica, and L. longirrostris within ground cover and G. cinerea speciosa, Q. rotundifolia, R. officinalis, T. zygis gracilis, and U. parviflorus within adjacent vegetation. Accordingly, habitat complexity showed a positive relationship with the abundance of key families of natural enemies and pollinators but not with the number of taxa. NMDS showed that plant richness and plant arrangement and scattering affected the key families differently, suggesting that each key family responds to their individual needs for plant resources but forming groups modulated by complexity. This pattern was especially seeing in predators and omnivores. Our findings support that the higher the plant richness and structure of a semi natural-habitat within an olive orchard, the higher the abundance and richness of a given arthropod community (a pattern found in natural ecosystems). The information presented here can be used by producers and technicians to increase the presence and abundance of natural enemies and pollinators within organic olive orchards, and thus improve the ecosystem services provided by semi-natural habitats. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=55 SRC="FIGDIR/small/429588v1_ufig1.gif" ALT="Figure 1"> View larger version (10K): org.highwire.dtl.DTLVardef@1937910org.highwire.dtl.DTLVardef@f1365borg.highwire.dtl.DTLVardef@279a14org.highwire.dtl.DTLVardef@1f4a476_HPS_FORMAT_FIGEXP M_FIG C_FIG

The growing global horticultural trade is having a steadily increasing impact on the rate at which alien species are introduced into new areas, partly because horticultural trade also entails the unintentional dispersal of many contaminant species. Although there are reports about noteworthy occurrences of alien plant species in garden centres, this phenomenon has hardly been studied systematically. To bridge this knowledge gap, we conducted systematic field surveys in 12 garden centres in Hungary to assess their alien flora. We hypothesised that (i) the number of alien species inhabiting a garden centre is positively correlated with its size, (ii) relative to their size, garden centres host a disproportionately large proportion of the local alien flora, and (iii) alien species inhabiting garden centres differ from the regional alien flora in their traits. We recorded altogether 93,788 individuals of 67 introduced species, seven of which have not yet been reported from the country. There was considerable variability in the number of species and individuals found in each garden centre, but there was no correlation between the size of the garden centres and the number of species they host. Despite their relatively small size, the studied garden centres hosted a considerable proportion of the local alien flora, indicating that they strongly accumulate alien species and that they can act as invasion hubs for several alien species. Alien species inhabiting garden centres differed from the regional alien flora in some of their trait values, indicating that the species that are most successful at establishing populations inside garden centres are both good dispersers and possess an effective resource-acquisitive strategy. We conclude that established alien plant populations in garden centres may induce local invasions, and in the meantime, individuals and seeds inside the containers of ornamental plants are regularly transported to distant areas by the customers. Therefore, plant species dispersed as contaminants of horticultural stock need to be better considered in invasion biology to reduce the threat they may present.

For the improvement and maintenance of the desirable ecological value of grasslands it is necessary to manage them in a way which maintains their structure and their long-term functioning. Extensive grazing plays a crucial role in the seasonal biomass removal, thereby it prevents litter accumulation and shrub encroachment. Defoliation and biomass removal are among the most important effects of grazing on the vegetation, while the sufficient quantity and quality of plant biomass is an important ecosystem service for animal husbandry. In order to maintain the long term functioning of pastures it is important to gather information about the amount of consumed biomass and the dietary choice of the grazers. Therefore, we studied the direct effects of grazing on species-rich meadow steppes in Central-Hungary and the underlying mechanisms of dietary choice of cattle using trait-based approach. We asked the following questions: (i) What are the direct effects of grazing on the main biomass fractions (litter, moss, forbs and graminoids)? (ii) Which traits distinguish the preferred and non-preferred vascular plant species? The studied pastures were divided into two adjacent units, which were managed differently in the study year: the grazed units were managed by grazing for three months before the sampling date, while the control units remained ungrazed until the sampling. We collected above-ground biomass samples, measured leaf traits and shoot nitrogen content of plants. The consumption of the litter and moss biomass was negligible, while the reduction of the live biomass of vascular plants was 65%. Grazing significantly decreased the flowering success of plants. Cattle consumed species characterized by high specific leaf area and high nitrogen content. Based on our results we emphasize that, in order to ensure the reproduction of most plant species in the long term, it is unfavourable to graze an area every year in the same period. Instead, it is recommended to use grazing in a mosaic spatial and temporal pattern. The livestock carrying capacity of an area and the long-term management of grasslands can be carefully planned based on biomass measurements and the nutritional value of plants, which is well indicated by some easily measurable plant properties such as specific leaf area and the nitrogen content of species.

O_LIAllocation to plant defense traits likely depends on resource supply, herbivory, and other plant functional traits such as the leaf economic spectrum (LES) traits. Yet, attempts to integrate defense and resource acquisitive traits remains elusive. C_LIO_LIWe assessed intraspecific correlations between different defense and LES traits in a widely distributed tropical savanna herb, Solanum incanum, a unique model species for studying allocations to physical, chemical, and structural defenses to mammalian herbivory. C_LIO_LIIn a multivariate trait space, the structural defenses - lignin and cellulose - were positively related to the resource conservative traits - low SLA and low leaf N. Phenolic content, a chemical defense, was positively associated with resource acquisitive traits - high SLA and high leaf N - while also being associated with an independent third component axis. Both principal components 1 and 3 were not associated with resource supply and herbivory intensity. In contrast, spine density - a physical defense - was orthogonal to the LES axis and positively associated with soil P and herbivory intensity. C_LIO_LISynthesis: These results suggest a hypothesized "pyramid" of trade-offs in allocation to defense along the LES and herbivory intensity axes. Therefore, future attempts to integrate defense traits with the broader plant functional trait framework needs a multifaceted approach that accounts for unique influences of resource acquisitive traits and herbivory intensity. C_LI

AimDark diversity refers to the set of species that are not observed in an area but could potentially occur based on suitable local environmental conditions. In this paper, we applied both niche-based and co-occurrence-based methods to estimate the dark diversity of vascular plant species in the subarctic tundra. We then aimed to unravel the drivers explaining (1) why some locations were missing relatively more suitable species than others, and (2) why certain plant species were more often absent from suitable locations than others. LocationThe Scandinavian tundra around Abisko, northern Sweden. MethodsWe calculated the dark diversity in 107 plots spread out across four mountain trails using four different methods. Two niche-based (Beals index and hypergeometric method) and two co-occurrences-based (climatic niche model and climatic niche model followed by species-specific threshold) methods. This was then followed by multiple generalized linear mixed models and general linear models to determine which habitat characteristics and species traits contributed most to the dark diversity. ResultsThe study showed a notable divergence in the predicted drivers of dark diversity depending on the method used. Nevertheless, we can conclude that plot-level dark diversity was generally 18% higher in areas at low elevations and 30% and 10% higher in areas with a low species richness or low levels of habitat disturbance, respectively. ConclusionOur findings call for caution when interpreting statistical findings of dark diversity estimates. Even so, all analyses point towards an important role for natural processes such as competitive dominance as main driver of the spatial patterns found in dark diversity in the northern Scandes.

Interspecific competition can strongly influence community structure and shape niche breadth and overlap. One of the main factors that determine the hummingbird community structure is competition for food. Hummingbirds functional attributes, such as beak length and body mass, influence nectar acquisition in the flowers, shaping foraging niches according to hummingbird dominance and foraging strategy. This study evaluates how the hummingbirds functional and behavioral attributes are related to plants assemblage in rocky outcrops habitats. We tested the following hypothesis: H1) Functional traits (beak length and body mass) are related to the richness and frequency of pollen grain morphotypes carried by hummingbirds; H2) Dominant and territorial hummingbirds carry a lower richness and frequency of pollen types when compared to subordinate hummingbirds, and H3) Hummingbird species carry different types of pollen grains. We conducted the study between September 2018 and March 2019 in a Campo Rupestre (rocky outcrops) in Southeastern Brazil. Hummingbirds were captured with a trap built based on trapdoors. We recorded their beak size and body masses, marked with commercial bird rings and ink on parts of the body, and then released. Behavioral responses to artificial feeders were collected regarding each visits time and duration and the outcome of aggressive interactions. The pollen adhered to the body parts was collected and identified in the laboratory. Our results showed that neither body size nor aggressive behaviors influenced pollen richness and frequency in rocky outcrops. Beak length was the most important hummingbirds attribute that influenced pollen richness, but not pollen frequency. Short-billed hummingbirds carried the greatest richness of pollen grains. Pollen grain richness and frequency were not related to hummingbird body mass or aggressive behavior. The hummingbird-pollen grain interaction network has shown to be generalized in the pollen grain transport. We conclude that hummingbirds beak length is the central morphological variable to measure pollen grain transport. It has direct implications for the pollination of different plant species.

Knowledge of spatial patterns of species richness (SR) is highly relevant for theoretical research in ecology and the development of conservation plans. In Poland, despite a long tradition of botanical surveys, vascular plant SR has not been mapped, nor have the correlations in richness among different plant species groups been explored. Here we used a recently published data set to examine spatial patterns and relationships among the joined SR of vascular plant species, including native species, archeophytes, neophytes, and species with high conservation value (i.e., red list species). The basic spatial unit employed was a 10 x 10 km grid from the Atlas of Distribution of Vascular Plants in Poland (ATPOL). We found that the richness patterns of native species, archeophytes, neophytes, and red-list species were positively correlated. The main patterns of SR and the percentage of particular groups in the joined SR were based on three components: (1) gradient of overall SR, (2) invasion level, and (3) peculiarity of flora in some regions resulting from the high number and proportion of rare species that often have high conservation value. In general, northeastern Poland was species-poor, while the Carpathian Mountain range, the uplands in southern Poland, and some parts of Wisa River valley had the highest SR concentrations. The location of SR hotspots usually did not overlap with the existing system of national parks. The correlations among native SR, high conservation value species, and neophyte SR suggest that biological invasions are among the most important threats to vascular plant diversity in Poland. Finally, we demonstrated that the presented maps, despite likely biases in SR assessments, seem to reflect general ecological gradients influencing vascular plant distribution in Poland.

Arbuscular mycorrhizal fungi (AMF) are amongst the most studied plant symbionts and regularly found in terrestrial plants. However, global estimates of AMF abundance amongst all land plants are difficult because i) the mycorrhizal status of many non-commercial, wild plant species is still unknown ii) numerous plant species engage in facultative symbiosis, meaning that they can, but do not always do, associate with mycorrhiza and iii) mycorrhizal status can vary amongst individuals of one same plant species at one location, as well as for different plant species within a given genus or family. To gain new insights to the pristine distribution of the plant-AMF symbiosis, we investigated the mycorrhizal status of one of the oldest lineages of extant vascular plants, Polypodiophyta (aka ferns), in one of the hotspots of natural plant diversification, the tropical rainforest. Providing a new data set of AMF abundance for 79 fern species, we hypothesized that (1) AMF would be found in 60-80% of the studied plants and (2) plant species with AMF symbionts would be more abundant than non-mycorrhizal species. Both hypotheses were rejected while unexpected observations were made: (1) AMF occurred in 33% of studied species, representing 56% of the studied fern families, (2) AMF colonisation was not correlated with species abundance, (3) a small but significant proportion of AMF-positive ferns was epiphytic (7%) and (4) as expected, mycorrhization was inconsistent among different populations of the same species. Together this empirical data supports recent reservations regarding global abundance of AMF, and further demonstrates that mycorrhization is not a taxonomic trait. In addition, the occurrence of AMF in epiphytic plants and no net benefits of AMF for plant abundance indicate that the mycorrhization observed here is on the commensalism, possibly parasitism, side of the symbiosis spectrum. HighlightsO_LISmall fraction of fern species mycorrhized (33% species level, 56% of families) C_LIO_LIMycorrhization of species can vary with location (facultative symbiosis) C_LIO_LIAMF colonisation does not increase plant species abundance C_LIO_LIAMF presence in epiphytic ferns suggests commensalism / parasitism C_LI

O_LIOrganic farming is seen as a prototype of ecological intensification able to conciliate crop productivity and biodiversity conservation in agricultural landscapes. However, how natural enemies, an important functional group supporting pest control services, respond to organic farming at different scales and in different landscape contexts remain unclear.\nC_LIO_LIUsing a hierarchical design within a vineyard-dominated region located in southwestern France, we examine the independent effects of organic farming and semi-natural habitats at the local and landscape scales on natural enemies.\nC_LIO_LIWe show that the proportion of organic farming is a stronger driver of species abundance than the proportion of semi-natural habitats and is an important facet of landscape heterogeneity shaping natural enemy assemblages. Although our study highlight a strong taxonomic group-dependency about the effect of organic farming, organic farming benefits to dominant species while rare species occur at the same frequency in the two farming systems.\nC_LIO_LIIndependently of farming systems, enhancing field age, reducing crop productivity, soil tillage intensity and pesticide use are key management options to increase natural enemy biodiversity.\nC_LIO_LISynthesis and Applications. Our study indicates that policies promoting the expansion of organic farming will benefit more to ecological intensification strategies seeking to enhance ecosystem services than to biodiversity conservation.\nC_LI

Mediterranean mountain grasslands are ecosystems of high ecological and economic value. They are shaped by the dry and warm climate and land use, such as grazing, although the combined effects of both drivers remain poorly understood. In this study, we analyzed shifts in functional composition in thirty-two plant communities in Mediterranean mountain grasslands of the Pindos Range (Greece) by measuring five plant functional traits related to resource acquisition in dominant plant species. We examined the adaptive value of each trait as well as community-level responses along a well-defined two-dimensional gradient of grazing intensity and aridity, using mixed models and functional diversity analyses, and tested whether individual species trait shifts are related to aridity and grazing intensity. At the community level, aridity decreased plant height and leaf area whereas grazing only affected traits associated with tissue recovery such as high specific leaf area (SLA) and low community-weighted mean leaf dry matter content (LDMC). As aridity increased, plant height functional dispersion decreased. This convergence pattern indicates a shift towards more similar growth forms under arid conditions. Species-specific analysis indicated various responses of traits to the interaction of aridity and grazing that could not be detected using only community-level patterns. Overall, our findings demonstrate that aridity and grazing act through separate functional axes at the community level, while their combined effects emerge through species-specific trait plasticity.

Ecosystem services mediated by biodiversity are essential for the well-being of human beings. While there is ample research on individual ecosystem services (such as pollination, nutrient cycling), there is now growing recognition to examine the interactions between multiple ecosystem services and their contribution to productivity in order to manage agroecosystems sustainably. In this study, we examined the interactions between pollination and pest control in coffee agroecosystems in Chiapas, Mexico. We tested how management of shade trees, particularly of nitrogen-fixing shade trees, at the farm scale mediated the outcome of the interactions between two ES. We found that there was no trade-off between pest control and pollination services despite the deterrence of pollinators by the dominant and aggressive ant species, Azteca sericeasur, which also controls the coffee berry borer, a major pest of Coffea arabica. We found additive effects of pest-control and pollination on early fruit set and fruit weight of coffee plants. Proximity to nitrogen-fixing shade trees had indirect effects on pest-control via the reduction of Azteca sericeasur activity on the coffee bushes. These findings highlight that ecosystem services are a result of complex interspecific interactions and that biodiversity-friendly management practices can promote favorable outcomes of these interactions on coffee yield.

Avian-mediated pest control is a significant ecosystem service with important economic implications. However, there is an overall paucity of experimental information about how landscape simplification affect its current level. Information on pest control by birds is missing in some permanent agroecosystems of worldwide importance, like olive orchards, that dominate vast areas in the Mediterranean region. We assess the effectiveness of insectivorous birds for controlling the two main pest insects in olive orchards and explore the effects of landscape complexity and distance to semi-natural patches on avian insectivore abundance and pest control. For this, we combine bird surveys with field experiments (branch exclusions and pest plasticine models) at the regional scale. Landscape heterogeneity increased the abundance and richness of insectivorous birds, which were also more abundant and diverse in semi-natural patches, compared to the farm olive matrix. Experiments evidenced that pest control by birds (measured as attack rates to plasticine models and pest damage) in the studied olive orchards is negligible, while pests were overall abundant and pest damage was high on most farms. This raises alarms about the status of avian pest control in this agroecosystem. Although landscape heterogeneity increased the abundance/richness of insectivorous birds, and favored some forest species, insectivorous bird abundance seems diluted in relation to prey availability in all landscapes. Thus, pest control by birds seems currently unsuccessful in olive orchards. Our results might be evidencing the loss of an ecosystem service due to a generalized massive decline of common and forest insectivorous birds. Key messageO_LIOlive orchards dominate extensive areas causing important landscape simplification. C_LIO_LIInsectivorous birds are more abundant in semi-natural patches within olive farms. C_LIO_LIField experiments show a low impact of birds on olive pests and damage. C_LIO_LIAvian-mediated pest biocontrol seems diluted by limited suitable habitat for birds. C_LIO_LIAgri-environmental measures should focus on increasing landscape complexity. C_LI

Pollinating insects are of great importance in natural ecosystems and agricultural landscapes. Despite their crucial role for food production, safeguarding pollination services is becoming increasingly challenging due to pollinator declines. Habitat loss and agricultural intensification are among the main drivers, causing a substantial reduction in the availability of floral resources. Despite efforts, the uptake of measures to halt these declines in agricultural landscapes is low. Implementation of a novel crop production system is therefore proposed as a solution to ensure food security whilst concomitantly minimising environmental degradation and the associated biodiversity loss. Agricultural diversification is one such strategy that is known to promote multiple ecosystem services. Yet, the effects of agricultural diversification on pollinator populations in farm-scale, observational studies remains understudied. Here, we examine the importance of small-scale, diverse horticultural systems (SDHS) to support wild pollinator communities. Floral resources and wild pollinators were sampled in both SDHSs and semi-natural grasslands (SNG) in 16 landscapes in Flanders, Belgium. During late summer, these SNGs provide and important source of floral resources, thereby serving as a benchmark habitat to which the SDHSs are compared. Our study highlights the value of SDHSs as they provide diverse and abundant floral resources compared to SNGs. Moreover, pollinator species richness and abundance were comparable between the two habitats. Conversely, floral resource and pollinator community composition differed, indicating that different pollinator communities used the complementary resources provided by both habitat types. Furthermore, we show that SNGs represent the most specialised habitat type. We therefore argue that SDHSs can be considered to be an additional, complementary source of floral resources to those provided by SNGs. However, these SDHSs cannot substitute SNGs, given the importance of these grasslands for pollinators.

While functional traits like body size have been extensively linked to species distributions, the influence of sensory traits on species responses to environmental changes remains underexplored. Particularly, the relationship between light sensitivity and niche segregation across different distributional extents - local habitat conditions and across entire landscapes - remains unclear. In this study, we examined bumblebee communities monitored across Norway on grassland and forest habitats within landscapes varying in forest cover within 1 km radii. We investigated whether the eye parameter - a visual trait measuring the trade-off between light sensitivity (high values) and visual resolution (low values) - was associated with local habitat types and the forest cover at the landscape scale. Additionally, we combined bumblebee-plant interactions with a plant trait, to determine if bumblebee light sensitivity correlated with the shade tolerance of the plants they foraged on. Our findings showed that bumblebee species with high eye parameters were more common and abundant in forest habitats and areas with greater forest cover, while species with low eye parameters showed the opposite trend. This pattern was also reflected at the community level, as indicated by the community-weighted mean of the eye parameter which increased with forest cover and was higher in forest habitats. Furthermore, bumblebees with higher eye parameters tended to forage on plants with greater shade tolerance. These results suggest that visual adaptations for light sensitivity contribute to shaping bumblebee species distributions across different scales. Overall, our study underscores the importance of pollinator vision in understanding species niches, in relation to habitat use and foraging behaviour. By relating pollinator visual abilities to plant niches for the first time, this study provides an important basis for future modelling of plant-pollinator interactions and targeted conservation measures for both plants and pollinators in forested landscapes.

In Colombia, coffee production has an ingrained cultural and economic importance. Coffee is cultivated in biodiverse areas using a variety of practices ranging from sun-exposed monocultures to mixed and shaded plantations. Management practices on this working landscape alter the composition of bird communities. We hypothesize that coffee agroecosystems homogenize bird communities by favoring the occupancy of non-forest dependent bird species and deterring forest dependent birds. We evaluate the effects of coffee plantations and associated metrics of vegetation structure on a subset of bird species in an agroforestry landscape in the Western Andes in Colombia and evaluate the hypothesis of community homogenization. We collected data in two consecutive years in 153 sites in coffee plantations and other habitats in Jardin, Colombia. In order to evaluate birds response to changes in the working landscape we made single-season occupancy models and used five covariates: coffee (binary covariate), foliage height diversity (FHD) and canopy height (CH) as proxies for coffee management practices, human footprint (LHFI), and elevation. Finally, we used generalized dissimilarity models (GDM) with the same covariates and geographical distance to evaluate the homogenization hypothesis among coffee sites. We identified 193 species (six endangered and five endemics) and modeled occupancy of 74 species. Coffee plantations significantly decreased the occupancy of 14 species while 13 were favored. In general, non-forest dependent species preferred lower FHD and lower CH values, and occurred at lower elevations with high LHFI. On the contrary, forest dependent species preferred higher FHD and CH, and were found at higher elevations. The GDM with best fit supported the hypothesis that coffee sites tend to be more similar than no-coffee sites, and that elevation and FHD explained most of the variation in dissimilarity. The working landscape in Jardin holds an important community of birds but coffee plantations are driving its homogenization. We anticipate that non-forest dependent birds will continue to colonize working landscapes, unless structural vegetation changes are promoted. Increasing FHD and CH is a potential strategy to improve forest dependent bird occupancy and reduce homogenization in Jardin.

A straightforward way to explore variation between communities is to calculate dissimilarity indices and relate them with environmental and spatial variables. Communities are most often represented by the (relative) abundances of taxa they comprise; however, more recently, the distribution of traits of organisms included in the communities has been shown more strongly related to ecosystem properties. In this study, we test whether taxon- or trait-based dissimilarity is correlated more tightly with environmental difference and geographical distance and how the abundance scale influences this correlation. Our study system is grassland vegetation in Hungary, where we sampled vegetation plots spanning a long productivity gradient from open dry grasslands to marshes in three sites. We considered three traits for vascular plants: canopy height, specific leaf area and seed mass. We obtained field estimates of normalized vegetation difference index (NDVI) as proxy of productivity (water availability) for each plot. We calculated between-community dissimilarities using a taxon-based and a trait-based index, using raw and square-root transformed abundances and presence/absence data. We fitted distance-based redundancy analysis models with NDVI difference and geographical distance on the dissimilarity matrices and evaluated them using variance partitioning. Then, using the pooled data, we calculated non-metric multidimensional scaling ordinations (NMDS) from all types of dissimilarity matrices and made pairwise comparisons using Procrustes analysis. Data analysis was done separately for the three sites. We found that taxonomical dissimilarity matches environmental and spatial variables better when presence/absence data is used instead of abundance. This pattern was mainly determined by the increasing variation explained by space at the presence/absence scale. In contrast to this trend, with trait-based dissimilarity, accounting for abundance increased explained variation significantly due to the higher explanatory power of NDVI. With abundance data, considering traits improved environmental matching to a great extent in comparison with taxonomical information. However, with presence/absence data, traits brought no advantage over taxon-based dissimilarity in any respect. Changing the abundance scale caused larger difference between ordinations in the case of trait-based dissimilarity than with taxonomical dissimilarity. We conclude that considering relevant traits improves environmental matching only if abundances are also accounted for. Supporting informationAdditional graphs supporting the results are presented as appendix. Open researchData used in this research are publicly available from Dryad ###link to be supplied upon acceptance###