Contrasting patterns of phylogenetic assemblage structure along the elevational gradient for major hummingbird clades

Abstract

Aim We evaluated the hypothesis that, given niche conservatism, relatedness of co-occurring hummingbird species of a given clade will increase at greater distances from the elevation where it originated. We also used prior knowledge of flight biomechanics and feeding specialization of hummingbird species (family Trochilidae) to evaluate which environmental variables were important predictors of changes in phylogenetic structure for each hummingbird clade.Location Ecuador.Methods We compiled species lists for 189 local hummingbird assemblages across major environmental gradients in Ecuador from a variety of published and non-published sources. For the entire family and each of the major hummingbird clades (hermits, emeralds, mangoes, coquettes and brilliants) we quantified the phylogenetic structure of each assemblage using the net relatedness index (NRI). This index calculates the standardized mean of all possible pairwise phylogenetic distances between co-occurring species. We related NRI for each clade to elevation, precipitation and vegetation-related variables using generalized additive models. ResultsOur findings support the prediction of an increase in the co-occurrence of close relatives away from the elevation of origin at the family level and for assemblages of mangoes and brilliants. The opposite pattern was found for assemblages of coquettes and emeralds. For the hermits, variation in phylogenetic structure was not explained by elevation. Clades with high levels of feeding specialization (hermits and brilliants) always included a vegetation-related variable as an important predictor of change in phylogenetic structure. Main conclusionsWe found no overall support for the conservatism and zone of origin hypotheses. Knowledge of each clade's natural history proved useful for predicting which environmental variables correlated with phylogenetic structure of local assemblages. Clades with the same elevation of origin appear to have radiated along the elevational gradient in association with different environmental factors.

Process-Based Species Pools Reveal the Hidden Signature of Biotic Interactions Amid the Influence of Temperature Filtering

“…Second, because the temperature niche is conserved in hummingbirds and we used temperature to define our species pools, it might be that particular clades are at least partly responsible for our observed patterns of evenness. Similar to our result, analyzing clades separately, Parra et al (2011) found patterns of phylogenetic evenness at high elevation for one of the two clades that radiated in the Andes (i.e., for brilliants but not coquettes) and for emeralds, which are also somewhat common in midelevation assemblages. Taken together, these results suggest that conservatism in the evolution of climatic niches, environmental filtering, and competitive interactions might interact to shape hummingbird assemblages, at least at high-and midelevation sites dominated by particular clades.…”

“…This content downloaded from 130.225.098.210 on April 06, 2016 03:06:51 AM clades occurs at the highest and coldest elevations (Parra et al 2010(Parra et al , 2011. In addition, temperature and precipitation have been shown to influence the composition and spatial turnover of hummingbird species in studies conducted in the same region Weinstein et al 2014).…”

“…We defined the cost of passing through a grid cell as the difference in mean elevation between that grid cell and the grid cell of origin. Elevation is a strong proxy for environmental similarity, a predictor of taxonomic beta diversity, and possibly a strong dispersal boundary in hummingbirds (Parra et al , 2011). The probability weights were then calculated as the accumulated cost along the lowest cost path from that grid cell.…”

“…Hummingbirds provide a useful test case for our approach because patterns of phylogenetic and trait structure appear to be influenced by the species pool definition (Parra et al 2011;González-Caro et al 2012). A single species pool based on species detected in a set of local communities yielded phylogenetic clustering at high elevations, which indicated that environmental filtering may have structured these hummingbird assemblages (Graham et al 2009).…”

Comunidades de aves y lepidópteros diurnos y las relaciones entre ellas en bosque nuboso y cafetal de Finca Santa Maura, Jinotega

“…El hecho que el grupo de nectarívoros muestre mayores relaciones con otros grupos en su riqueza de especies se debe en parte a que la familia Trochilidae es un grupo que muestra cierta relación a los hábitats conservados y las altitudes (Parra, Rahbek, McGuire & Graham, 2011). Además, este grupo, en las zonas del Centro de Nicaragua presenta mayor riqueza de especies (Martínez-Sánchez, 2007), por lo que es un grupo de importancia ecológica en este ecosistema.…”