The temporal build-up of hummingbird/plant mutualisms in North America and temperate South America

Background The 361 species of hummingbirds that occur from Alaska to Patagonia pollinate ~7,000 plant species with flowers morphologically adapted to them. To better understand this asymmetric diversity build-up, this study analyzes the origin of hummingbird/plant mutualisms in North America and temperate South America, based on new compilations of the 184 hummingbird-adapted species in North America, the 56 in temperate South America, and complete species-level phylogenies for the relevant hummingbirds in both regions, namely five in temperate South America and eight in North America. Because both floras are relatively well sampled phylogenetically, crown or stem ages of many representative clades could be inferred. The hummingbird chronogram was calibrated once with fossils, once with substitutions rates, while plant chronograms were taken from the literature or in 13 cases newly generated. Results The 184 North American hummingbird-adapted species belong to ca. 70 lineages for 19 of which (comprising 54 species) we inferred divergence times. The 56 temperate South American hummingbird-adapted species belong to ca. 35 lineages, for 17 of which (comprising 25 species) we inferred divergence times. The oldest hummingbirds and hummingbird-adapted plant lineages in the South American assemblage date to 16–17 my, those in the North American assemblage to 6–7 my. Few hummingbird-pollinated clades in either system have >4 species. Conclusions The asymmetric diversity build-up between hummingbirds and the plants dependent on them appears to arise not from rapid speciation within hummingbird-pollinated clades, but instead from a gradual and continuing process in which independent plant species switch from insect to bird pollination. Diversification within hummingbird-pollinated clades in the temperate regions of the Americas appears mainly due to habitat specialization and allopatric speciation, not bird pollination per se. Interaction tanglegrams, even if incomplete, indicate a lack of tight coevolution as perhaps expected for temperate-region mutualisms involving nectar-feeding vertebrates

The temporal build-up of hummingbird/plant mutualisms in North America and temperate South America

Background The 361 species of hummingbirds that occur from Alaska to Patagonia pollinate ~7,000 plant species with flowers morphologically adapted to them. To better understand this asymmetric diversity build-up, this study analyzes the origin of hummingbird/plant mutualisms in North America and temperate South America, based on new compilations of the 184 hummingbird-adapted species in North America, the 56 in temperate South America, and complete species-level phylogenies for the relevant hummingbirds in both regions, namely five in temperate South America and eight in North America. Because both floras are relatively well sampled phylogenetically, crown or stem ages of many representative clades could be inferred. The hummingbird chronogram was calibrated once with fossils, once with substitutions rates, while plant chronograms were taken from the literature or in 13 cases newly generated. Results The 184 North American hummingbird-adapted species belong to ca. 70 lineages for 19 of which (comprising 54 species) we inferred divergence times. The 56 temperate South American hummingbird-adapted species belong to ca. 35 lineages, for 17 of which (comprising 25 species) we inferred divergence times. The oldest hummingbirds and hummingbird-adapted plant lineages in the South American assemblage date to 16–17 my, those in the North American assemblage to 6–7 my. Few hummingbird-pollinated clades in either system have >4 species. Conclusions The asymmetric diversity build-up between hummingbirds and the plants dependent on them appears to arise not from rapid speciation within hummingbird-pollinated clades, but instead from a gradual and continuing process in which independent plant species switch from insect to bird pollination. Diversification within hummingbird-pollinated clades in the temperate regions of the Americas appears mainly due to habitat specialization and allopatric speciation, not bird pollination per se. Interaction tanglegrams, even if incomplete, indicate a lack of tight coevolution as perhaps expected for temperate-region mutualisms involving nectar-feeding vertebrates

Seasonal changes in odour preferences by male euglossine bees (Hymenoptera: Apidae) and their ecological implications

Orchid bees are an important group of specialized insect pollinators in the Neotropics. Male orchid bees are attracted by a wide range of aromatic substances often produced by flowers. Previous studies found that in some species the males change their aromatic preferences between seasons. In our study we documented seasonal changes of aromatic preferences in five euglossine bee assemblages along a 380-km-long seasonality and precipitation gradient and related them to climatic factors. We found that the proportion of species per site showing changes in their aromatic preference between seasons increased with climatic seasonality towards the south. Those species mainly belong to the genus Euglossa, subgenus Euglossa. We conclude that climatic seasonality mainly affects the orchid bees via the turnover of the aromatic substances provided by the plants. Further, we suggest that the ability to change the aromatic preference between seasons could be interpreted as a phylogenetic pre-adaptation that enabled some species to colonize climatically strongly seasonal habitats

DOCUMENTATION FOR ENVIRONMENTAL RISK ASSESSMENT AND MITIGATION OF BUILT CULTURAL HERITAGE IN CENTRAL ASIA: THE ERAMCA PROJECT

The ERASMUS+ initiative funded, in 2019, a Capacity Building project named ERAMCA (Environmental Risk Assessment and Mitigation in Central Asia) to build up a study plan at the Master of Science level (120 ECTS in 2 academic years) open to Architects, Civil, Building, and Environmental Engineers to build-up a new generation of professionals able to work in a team with different specialities to document Cultural Heritage assets by considering environmental risks. These new professionals will be able to set up the helpful basic knowledge to plan future actions of preservation and enhancement by following the most recent development in the restoration field at the international level.The ERAMCA project started with a survey of the basic knowledge of architects and engineers in Uzbekistan and Tajikistan on the documentation of natural and anthropic risks.By considering the common knowledge, the Partners of the ERAMCA project (3 European Universities from Italy, Germany, and Croatia and 4 Universities from Uzbekistan and Tajikistan) realised a study plan by concentrating the teaching activity on the following disciplines: Geomatics, Restoration, Structure and Seismic Engineering, Hydrogeology and Geotechnics.ERAMCA project is in its last year of activity, and the final results can be presented and discussed among the Cultural Heritage Documentation community to offer possible suggestions for future actions to diffuse documentation strategies.</p

Macroevolution of the plant–hummingbird pollination system

ABSTRACTPlant–hummingbird interactions are considered a classic example of coevolution, a process in which mutually dependent species influence each other's evolution. Plants depend on hummingbirds for pollination, whereas hummingbirds rely on nectar for food. As a step towards understanding coevolution, this review focuses on the macroevolutionary consequences of plant–hummingbird interactions, a relatively underexplored area in the current literature. We synthesize prior studies, illustrating the origins and dynamics of hummingbird pollination across different angiosperm clades previously pollinated by insects (mostly bees), bats, and passerine birds. In some cases, the crown age of hummingbirds pre‐dates the plants they pollinate. In other cases, plant groups transitioned to hummingbird pollination early in the establishment of this bird group in the Americas, with the build‐up of both diversities coinciding temporally, and hence suggesting co‐diversification. Determining what triggers shifts to and away from hummingbird pollination remains a major open challenge. The impact of hummingbirds on plant diversification is complex, with many tropical plant lineages experiencing increased diversification after acquiring flowers that attract hummingbirds, and others experiencing no change or even a decrease in diversification rates. This mixed evidence suggests that other extrinsic or intrinsic factors, such as local climate and isolation, are important covariables driving the diversification of plants adapted to hummingbird pollination. To guide future studies, we discuss the mechanisms and contexts under which hummingbirds, as a clade and as individual species (e.g. traits, foraging behaviour, degree of specialization), could influence plant evolution. We conclude by commenting on how macroevolutionary signals of the mutualism could relate to coevolution, highlighting the unbalanced focus on the plant side of the interaction, and advocating for the use of species‐level interaction data in macroevolutionary studies

The macroecology of phylogenetically structured hummingbird-plant networks

Aim To investigate the association between species richness, species' phylogenetic signal, insularity and historical and current climate with hummingbird-plant network structure. Location 54 communities along a c. 10,000 kilometer latitudinal gradient across the Americas (39ºN - 32ºS), ranging from sea level to c. 3700 m asl, located on the mainland and on islands, and covering a wide range of climate regimes. Methods We measured null-modeled corrected complementary specialization and bipartite modularity (compartmentalization) in networks of quantitative interactions between hummingbird and plant species. Using an ordinary least squares multi-model approach, we examined the influence of species richness, phylogenetic signal, insularity, and current and historical climate conditions on network structure. Results Phylogenetically-related species, especially plants, showed a tendency to interact with a similar array of partners. The spatial variation in network structure exhibited a constant association with species' phylogeny (R2=0.18-0.19). Species richness and environmental factors showed the strongest associations with network structure (R2=0.20-0.44; R2138 =0.32-0.45, respectively). Specifically, higher levels of complementary specialization and modularity were associated to species-rich communities and communities in which closely-related hummingbirds visited distinct sets of flowering species. On the mainland, warmer temperatures and higher historical temperature stability associated to higher levels of complementary specialization. Main conclusions Previous macroecological studies of interaction networks have highlighted the importance of environment and species richness in determining network structure. Here, for the first time, we report an association between species phylogenetic signal and network structure at macroecological scale. Specifically, null model corrected complementary specialization and modularity exhibited a positive association with species richness and a negative association with hummingbird phylogenetic signal, indicating that both high richness and high inter-specific competition among closely-related 150 hummingbirds exhibit important relationships with specialization in hummingbird-plant networks. Our results document how species richness, phylogenetic signal and climate associate with network structure in complex ways at macroecological scale

Ecological filtering shapes the impacts of agricultural deforestation on biodiversity

Funding: This project was funded by the National Natural Science Foundation of China (Grants 32122057 and 3198810 to FH) and the Ministry of Science and Technology of China (Grant 2022YFF0802300 to FH), and received further support from Tsinghua University Initiative Scientific Research Program (Grant 20223080017 to LY).The biodiversity impacts of agricultural deforestation vary widely across regions. Previous efforts to explain this variation have focused exclusively on the landscape features and management regimes of agricultural systems, neglecting the potentially critical role of ecological filtering in shaping deforestation tolerance of extant species assemblages at large geographical scales via selection for functional traits. Here we provide a large-scale test of this role using a global database of species abundance ratios between matched agricultural and native forest sites that comprises 71 avian assemblages reported in 44 primary studies, and a companion database of 10 functional traits for all 2,647 species involved. Using meta-analytic, phylogenetic and multivariate methods, we show that beyond agricultural features, filtering by the extent of natural environmental variability and the severity of historical anthropogenic deforestation shapes the varying deforestation impacts across species assemblages. For assemblages under greater environmental variability—proxied by drier and more seasonal climates under a greater disturbance regime—and longer deforestation histories, filtering has attenuated the negative impacts of current deforestation by selecting for functional traits linked to stronger deforestation tolerance. Our study provides a previously largely missing piece of knowledge in understanding and managing the biodiversity consequences of deforestation by agricultural deforestation.Peer reviewe

Predicting bee community responses to land-use changes: Effects of geographic and taxonomic biases

Land-use change and intensification threaten bee populations worldwide, imperilling pollination services. Global models are needed to better characterise, project, and mitigate bees' responses to these human impacts. The available data are, however, geographically and taxonomically unrepresentative; most data are from North America and Western Europe, overrepresenting bumblebees and raising concerns that model results may not be generalizable to other regions and taxa. To assess whether the geographic and taxonomic biases of data could undermine effectiveness of models for conservation policy, we have collated from the published literature a global dataset of bee diversity at sites facing land-use change and intensification, and assess whether bee responses to these pressures vary across 11 regions (Western, Northern, Eastern and Southern Europe; North, Central and South America; Australia and New Zealand; South East Asia; Middle and Southern Africa) and between bumblebees and other bees. Our analyses highlight strong regionally-based responses of total abundance, species richness and Simpson's diversity to land use, caused by variation in the sensitivity of species and potentially in the nature of threats. These results suggest that global extrapolation of models based on geographically and taxonomically restricted data may underestimate the true uncertainty, increasing the risk of ecological surprises