Phylogenetic relatedness of co‐occurring waterbird communities: a test of Darwin's competition‐relatedness hypothesis

Abstract

The competition–relatedness hypothesis of Darwin states that competition is greater among species that are phylogenetically closely‐related, and such species will tend to appear in separate communities (i.e. the species within communities will be phylogenetically overdispersed). Many studies have tested (and mainly refuted) this hypothesis for plant and bacterial communities. Results for the few studies with avian species are not conclusive. We tested Darwin's hypothesis for waterbirds using a set of open, artificial fish ponds in Doñana, south‐western Spain, that provide relatively homogeneous habitat where competition is likely to be intense. Monthly counts of 38 ponds (for 11 months, i.e. 418 censuses) recorded 76 bird species. Darwin's hypothesis predicted that species appearing in the same pond would be less related phylogenetically than expected if species occurred randomly across ponds and months according to the structure of the overall community across the entire pond complex. However, the waterbird community did not show a predominantly overdispersed pattern, suggesting that interspecific competition among phylogenetically related species was not the main force structuring communities. In contrast, the proportion of clustered communities was higher than expected throughout the annual cycle, indicating that related waterbirds tend to co‐occur on the same site, probably because they have similar microhabitat preferences. Clustering patterns were mainly driven by abundant and closely related duck species, and also by shorebirds. However, few individual pond communities remained significantly different from random after correction for multiple testing. Furthermore, the probability of co‐occurrence of a given species pair was negatively related to the phylogenetic distance between them. In conclusion, our study shows waterbird communities are mainly phylogenetically clustered or random, and do not support the competition‐relatedness hypothesis.

Comparing the diversity and composition of waterbird functional traits between natural, restored, and artificial wetlands

“…This suggests that in all wetland types (except for Art) the most abundant breeding species tend to be more functionally different from one another than the most abundant wintering species. This may indicate lower inter‐specific competition during winter, although Sebastián‐González and Green (2017) found no evidence in Afp for a seasonal change in interspecific competition based on co‐occurrence of closely related species. Similarly, Bidwell, Green, and Clark (2014) found no evidence that interspecific competition influences spatial distribution of breeding ducks in a prairie wetland complex.…”

“…Thus, although located in former temporary marsh areas, they had an artificial hydrology and relatively stable water levels. Five of them were extensive fish ponds used to raise estuarine fish of commercial value, in which the food supply available to waterbirds has been relatively well studied (Rodríguez‐Perez & Green, 2012; Sebastián‐González & Green, 2017; Walton, Vilas, Cañavate, et al., 2015; Walton, Vilas, Coccia, et al., 2015).…”

Is the spread of the alien water boatman Trichocorixa verticalis verticalis (Hemiptera, Corixidae) aided by zoochory and drought resistant eggs?

“…Approximately 300 adults of T. v. verticalis were collected during each of six visits to Veta la Palma fish ponds (VLP) in Doñana Natural Park (see Céspedes, et al., 2019; Sebastián‐González & Green, 2017; Walton et al., 2015 for further information concerning this area, and its flora and fauna; Table 1). We measured temperature, conductivity, and salinity by spot sampling in situ using a conductivity meter (WTW® ProfiLine Cond 3,110).…”

Seasonal dynamics of waterbird assembly mechanisms revealed by patterns in phylogenetic and functional diversity in a subtropical wetland

“…We identified seasonal differences in the number of the pairs of species that exhibited non‐random co‐occurrence patterns. First, we calculated the standardized effect size of the co‐occurrence (SES.COOC):where COOC obs is the observed co‐occurrence of the assemblage, COOC mean is the mean value of the co‐occurrence of all the simulated assemblages, and SD cooc is the standard deviation of the co‐occurrence values of all the simulated assemblages (Griffith, Veech & Marsh, ; Sebastián‐González & Green, ). Significance was determined at the 5% level ( p < 0.05), and we repeated the analyses using a Bonferroni correction ( p < 0.01).…”

“…For example, the relative importance of top‐down control of basic resources has been shown to shift with climatic seasonal changes, with stronger top‐down impact during high‐diversity periods (Paszkowski & Tonn, ). Previous studies of phylogenetic assembly of wintering waterbirds have found a dominant phylogenetic clustering pattern, suggesting that waterbird assemblages are structured by similar microhabitat preferences (Sebastián‐González & Green, ). However, summer assemblages of song birds in temperate and tropical forests appear to generally be assembled by biotic interactions (Gomez, Bravo, Brumfield, Tello & Cadena, ).…”