BEYOND HUMMINGBIRD-FLOWERS: THE OTHER SIDE OF ORNITHOPHILY IN THE NEOTROPICS

Polinização por aves na região Neotropical é amplamente conhecida como uma importante interação ecossistêmica, mas as aves que pousam e que visitam flores são ainda vistas como meras oportunistas. Apesar dessas outras aves não dependerem somente de recursos florais, existem muitas plantas que dependem exclusivamente delas para a sua polinização. Essas flores apresentam características, incluindo morfologia e diferentes tipos de recursos, muito diferentes daquelas de flores ornitófilas polinizadas por beija-flores. Revisamos a síndrome de ornitofilia e a subdividimos nas duas formas de exploração para determinar as características florais que devem favorecer a polinização por aves que adejam e por aves que pousam na região Neotropical. Listamos as aves que pousam mencionadas na literatura para ter uma visão da riqueza de aves neotropicais que atuam como polinizadoras. Esperamos que quanto mais estudos no dossel florestal nos Neotrópicos, mais interações entre aves que pousam e flores devem ser observadas e revelar seu real papel para a biologia de ambos os grupos

Spatial distance and climate determine modularity in a cross-biomes plant–hummingbird interaction network in Brazil

Aim: We examined the effects of space, climate, phylogeny and species traits on module composition in a cross-biomes plant–hummingbird network. Location: Brazil, except Amazonian region. Methods: We compiled 31 local binary plant–hummingbird networks, combining them into one cross-biomes metanetwork. We conducted a modularity analysis and tested the relationship between species’ module membership with traits, geographical location, climatic conditions and range sizes, employing random forest models. We fitted reduced models containing groups of related variables (climatic, spatial, phylogenetic, traits) and combinations of groups to partition the variance explained by these sets into unique and shared components. Results: The Brazilian cross-biomes network was composed of 479 plant and 42 hummingbird species, and showed significant modularity. The resulting six modules conformed well to vegetation domains. Only plant traits, not hummingbird traits, differed between modules, notably plants’ growth form, corolla length, flower shape and colour. Some modules included plant species with very restricted distributions, whereas others encompassed more widespread ones. Widespread hummingbirds were the most connected, both within and between modules, whereas widespread plants were the most connected between modules. Among traits, only nectar concentration had a weak effect on among-module connectivity. Main conclusions: Climate and spatial filters were the main determinants of module composition for hummingbirds and plants, potentially related to resource seasonality, especially for hummingbirds. Historical dispersal-linked contingency, or environmental variations not accounted for by the explanatory factors here evaluated, could also contribute to the spatial component. Phylogeny and morphological traits had no unique effects on the assignment of species to modules. Widespread species showed higher within- and/or among-module connectivity, indicating their key role connecting biomes, and, in the case of hummingbirds, communities within biomes. Our results indicate that biogeography and climate not only determine the variation of modularity in local plant–animal networks, as previously shown, but also affect the cross-biomes network structure. © 2018 John Wiley & Sons Lt

Functional diversity mediates macroecological variation in plant–hummingbird interaction networks

Aim: Species interaction networks are known to vary in structure over large spatial scales. We investigated the hypothesis that environmental factors affect interaction network structure by influencing the functional diversity of ecological communities. Notably, we expect more functionally diverse communities to form interaction networks with a higher degree of niche partitioning. Locatio