6 research outputs found
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 (39ÂșN - 32ÂșS), 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
PRESERVACIĂN DE CEPAS DE HONGOS SILVESTRES Auricularia fuscosuccinea y Crepidotus palmarum, CONSUMIDOS EN LA VEREDA MONTE Y PINAL, PAUNA â BOYACĂ
Functional diversity mediates macroecological variation in plantâhummingbird interaction networks
© 2018 John Wiley & Sons Ltd 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. Location: Americas. Time period: Current. Major taxa studied: Hummingbirds and their nectar plants. Methods: We used a large dataset comprising 74 quantitative plantâhummingbird interaction networks distributed across the Americas, along with morphological trait data for 158 hummingbird species. First, we used a model selection approach to evaluate associations between the environment (climate, topography and insularity), species richness and hummingbird functional diversity as predictors of network structure (niche partitioning, i.e., complementary specialization and modularity). Second, we used structural equation models (SEMs) to ask whether environmental predictors and species richness affect network structure directly and/or indirectly through their influence on hummingbird functional diversity. For a subset of 28 networks, we additionally evaluated whether plant functional diversity was associated with hummingbird functional diversity and network structure. Results: Precipitation, insularity and plant richness, together with hummingbird functional diversity (specifically, functional dispersion), were consistently strong predictors of niche partitioning in plantâhummingbird networks. Moreover, SEMs showed that environmental predictors and plant richness affected network structure both directly and indirectly through their effects on hummingbird functional diversity. Plant functional diversity, however, was unrelated to hummingbird functional diversity and network structure. Main conclusions: We reveal the importance of hummingbird functional diversity for niche partitioning in plantâhummingbird interaction networks. The lack of support for similar effects for plant functional diversity potentially indicates that consumer functional diversity might be more important for structuring interaction networks than resource functional diversity. Changes in pollinator functional diversity are therefore likely to alter the structure of interaction networks and associated ecosystem functions
The influence of biogeographical and evolutionary histories on morphological traitâmatching and resource specialization in mutualistic hummingbirdâplant networks
This is the author accepted manuscript. The final version is available from Wiley via the DOI in this recordData availability statement: Data deposited in the Dryad Digital Repository:
https://doi.org/10.5061/dryad.rr4xgxd7n, (Dalsgaard et al., 2021).1. Functional traits can determine pairwise species interactions, such as those between plants and
pollinators. However, the effects of biogeography and evolutionary history on trait-matching
and trait-mediated resource specialization remain poorly understood.
2. We compiled a database of 93 mutualistic hummingbird-plant networks (including 181
hummingbird and 1,256 plant species), complemented by morphological measures of
hummingbird bill and floral corolla length. We divided the hummingbirds into their principal
clades and used knowledge on hummingbird biogeography to divide the networks into four
biogeographical regions: Lowland South America, Andes, North & Central America, and the
Caribbean islands. We then tested: (i) whether hummingbird clades and biogeographical regions
differ in hummingbird bill length, corolla length of visited flowers and resource specialization,
and (ii) whether hummingbirdsâ bill length correlates with the corolla length of their food plants
and with their level of resource specialization.
3. Hummingbird clades dominated by long-billed species generally visited longer flowers and
were the most exclusive in their resource use. Bill and corolla length and the degree of resource
specialization were similar across mainland regions, but the Caribbean islands had shorter
flowers and hummingbirds with more generalized interaction niches. Bill and corolla length
correlated in all regions and most clades, i.e. trait-matching was a recurrent phenomenon in
hummingbird-plant associations. In contrast, bill length did not generally mediate resource
specialization, as bill length was only weakly correlated with resource specialization within one
hummingbird clade (Brilliants) and in the regions of Lowland South America and the Andes in
which plants and hummingbirds have a long co-evolutionary history. Supplementary analyses
including bill curvature confirmed that bill morphology (length and curvature) does not in
general predict resource specialization.
4. These results demonstrate how biogeographical and evolutionary histories can modulate the
effects of functional traits on species interactions, and that traits better predict functional groups
of interaction partners (i.e. trait-matching) than resource specialization. These findings reveal
that functional traits have great potential, but also key limitations, as a tool for developing more
mechanistic approaches in community ecologyIndependent Research Fund DenmarkDanish National Research FoundationCAPESCNPqESDEPED-UATxFAPESBConsejo Nacional para Investigaciones CientĂficas y TecnolĂłgicas (CONICIT)Hesseâs Ministry of Higher Education, Research, and the ArtsNational Council of Science and Technology (CONACYT)Instituto de EcologĂaCOLCIENCIASFundaciĂłn ProAvesAmerican Bird ConservancyRoyal Commission for the Exhibition of 1851US ArmyCERL-ERDCBritish Ecological SocietyBiodiversity TrustAnglo Peruvian SocietyEuropean Union Horizon 202