scholarly journals Radiating despite a lack of character: closely related, morphologically similar, co-occurring honeyeaters have diverged ecologically

2015 ◽  
Author(s):  
Eliot T Miller ◽  
Sarah K Wagner ◽  
Luke J Harmon ◽  
Robert E Ricklefs
Keyword(s):  
Community Structure ◽  
Foraging Behavior ◽  
Phylogenetic Diversity ◽  
Environmental Gradients ◽  
Morphological Trait ◽  
New Method ◽  
Similar Degree ◽  
Similar Species ◽  
Trait Evolution ◽  
Trait Diversity

The 75 species of Australian honeyeaters (Meliphagidae) are morphologically and ecologically diverse, with species feeding on nectar, insects, fruit, and other resources. We investigated ecomorphology and community structure of honeyeaters across Australia. First, we asked to what degree morphology and ecology (foraging behavior) are concordant. Second, we estimated rates of trait evolution. Third, we compared phylogenetic and trait community structure across the broad environmental gradients of continental Australia. We found that morphology explained 37% of the variance in ecology (and 62% vice versa), and that recovered multivariate ecomorphological relationships incorporated well-known bivariate relationships. Clades of large-bodied species exhibited elevated rates of morphological trait evolution, while members of Melithreptus showed slightly faster rates of ecological trait evolution. Finally, ecological trait diversity did not decline in parallel with phylogenetic diversity along a gradient of decreasing precipitation. We employ a new method (trait fields) and extend another (phylogenetic fields) to show that while species from phylogenetically clustered assemblages co-occur with morphologically similar species, these species are as varied in foraging behavior as those from more diverse assemblages. Thus, although closely related, these arid-adapted species have diverged in ecological space to a similar degree as their mesic counterparts, perhaps mediated by competition.

scholarly journals Seasonal quantitative dynamics and ecology of pelagic rotifers in an acidified boreal lake

2017 ◽  
Vol 77 (1) ◽  
Author(s):  
Svein Birger Wærvågen ◽  
Tom Andersen
Keyword(s):  
Community Structure ◽  
Environmental Gradients ◽  
Seasonal Succession ◽  
Biotic Interactions ◽  
Resource Limitation ◽  
Local Environment ◽  
Food Competition ◽  
Variance Partitioning ◽  
Boreal Lake ◽  
Rotifer Community

Lake Gjerstadvann is a dimictic, oligotrophic, slightly acidified boreal lake in southern Norway (northwest Europe). The planktonic rotifer community of this lake was studied quantitatively during one year in order to investigate the impacts of the local environment and biotic interactions on seasonal succession and habitat selection. Pure suspension feeders (mainly Keratella spp., Conochilus spp., and Kellicottia longispina) together with raptorial graspers or specialised feeders (mainly Polyarthra spp. and Collotheca spp.) dominated the rotifer community over prolonged periods, whereas carnivorous/omnivorous species (mainly Asplanchna priodonta) were extremely uncommon. Low bicarbonate buffering capacity resulted in a distinctive seasonal oscillating pH between 5.0 and 5.6, defining a special acid-transition lake category. The pH values were highest in the productive period during summer, and lowest during ice break-up coinciding with the peak reactive aluminium concentrations of 250-300 mg L-1. As in typical Norwegian boreal perch lakes, the most abundant cladoceran was Bosmina longispina due to perch predation on the genus Daphnia. Rotifer community structure was significantly related to temperature and oxygen (P=0.001 and P=0.022), illustrating the important effects of the seasonal cycle and vertical density stratification. The most significant competition indicator species were B. longispina and Eudiaptomus gracilis (both with P=0.001). A variance partitioning indicated that 14% of the total community composition variance could only be explained by biotic interactions, while 19% of the variance could be attributed to environmental gradients. Of the variance, 23% could not be resolved between biotic interactions and environmental gradients, while a residual of 44% was not explainable by any of the variables. Acid conditions alone cannot account for all the observed changes in the rotifer community of this lake with low humic content, since resource limitation and food competition are also important factors shaping rotifer population dynamics and the community structure.

Effects of sediment nutrients and depth on small-scale spatial heterogeneity of submersed macrophyte communities in Lake Pleasant, Pennsylvania

2004 ◽  
Vol 61 (8) ◽  
pp. 1493-1502 ◽  
Author(s):  
R K Johnson ◽  
M L Ostrofsky
Keyword(s):  
Organic Matter ◽  
Community Structure ◽  
Spatial Heterogeneity ◽  
Environmental Gradients ◽  
Small Scale ◽  
Sediment Characteristics ◽  
Available Nitrogen ◽  
Total N ◽  
Available N ◽  
Prevailing Paradigm

Sediment concentrations of total and available nitrogen (N), phosphorus (P), and potassium (K) and organic matter from the littoral zone of Lake Pleasant, Pennsylvania, were highly variable. Only organic matter and total N were correlated with depth, however. This result suggests the existence of more complex environmental gradients than the prevailing paradigm of monotonic changes in sediment characteristics with increasing depth. The spatial heterogeneity of submersed aquatic plant communities was significantly correlated with depth, and available N and P. Canonical correspondence analysis demonstrated that these three factors explained 38% of the variance in community structure. Other sediment characteristics (available K, organic matter, and total N, P and K) were not significant by themselves, but all variables combined explained 63% of community-structure variance. Cluster analysis identified species or groups of species typical of endpoints on the depth versus nutrient axes. Myriophyllum exalbescens was typical of deep sites with relatively nutrient-rich sediments, whereas deep nutrient-poor sites were dominated by Vallisneria americana and Megalodonta beckii. Shallow nutrient-rich sites were dominated by several species of Potamogeton and Elodea canadensis, and shallow nutrient-poor sites were dominated by Heteranthera dubia and Najas flexilis. These results demonstrate the importance of sediment characteristics in determining macrophytes' community structure within lakes.

scholarly journals Change in the meiofauna community structure of sandy beaches of the Nuevo Gulf (Chubut, Argentina)

2012 ◽  
Vol 52 (34) ◽  
pp. 411-422 ◽  
Author(s):  
Carlos A. Harguinteguy ◽  
M. Noelia Cofré ◽  
Catalina T. Pastor de Ward
Keyword(s):  
Community Structure ◽  
Environmental Gradients ◽  
Sandy Beaches ◽  
Core Tube ◽  
Meiofauna Community ◽  
Diameter Core ◽  
Abiotic Variables ◽  
Abundance And Diversity ◽  
One Way Anova ◽  
Main Factor

The composition and distribution of the benthic meiofauna assemblages of the Nuevo Gulf (Chubut, Argentina) are described in relation to abiotic variables. The meiofauna and sediment samples were collected in the intertidal zone of four sandy beaches with different anthropic disturbances in June 2005. The samples were obtained at 20 sampling sites using a 2.5 cm diameter core tube at a depth of 10 cm. A total of 13 meiofauna taxa were identified, with the meiofauna being primarily represented by nematodes, gastrotrichs, ciliates and polychaetes and the meiofauna abundances ranging from 1.5 × 10³ to 6.5 × 10³ ind. 10 cm‑2. Univariate (one-way ANOVA test) and multivariate (ANOSIM/MDS test) analyses showed clear dissimilarities in community structures between sites with anthropic effects and those in pristine condition, revealed by the significant differences were found between beaches near to and far way from a city with port activity. The meiofaunal assemblage varied in abundance and diversity, and these changes in the community structure may have been related to environmental gradients on the shore. The BIO‑ENV analysis showed that the redox potential discontinuity depth might be the main factor in the spatial distribution of organisms.

The Dynamic Cultivation System: A new method for the detection of temporal shifts in microbial community structure in clay

2012 ◽  
Vol 65-66 ◽  
pp. 53-56 ◽  
Author(s):  
René Kaden ◽  
Eve Menger-Krug ◽  
Katja Emmerich ◽  
Kerstin Petrick ◽  
Martin Mühling ◽  
...  
Keyword(s):  
Community Structure ◽  
Microbial Community ◽  
Microbial Community Structure ◽  
New Method ◽  
Cultivation System ◽  
System A ◽  
Dynamic Cultivation ◽  
Temporal Shifts

scholarly journals Community structure of tenebrionid beetles in the Ulan Buh Desert (Inner Mongolia, China) (Coleoptera: Tenebrionidae)

2019 ◽  
Vol 51 (2) ◽  
pp. 193-200 ◽  
Author(s):  
Yiping Niu ◽  
Guodong Ren ◽  
Giulia Lin ◽  
Letizia Di Biase ◽  
Simone Fattorini
Keyword(s):  
Community Structure ◽  
Plant Cover ◽  
Species Abundance ◽  
Local Environment ◽  
Gobi Desert ◽  
Similar Species ◽  
Abundance Patterns ◽  
Central Asian ◽  
Species Abundance Distributions ◽  
Ulan Buh Desert

Tenebrionids are a conspicuous faunal component of Central Asian deserts, but little is known about their community ecology. We investigated how tenebrionid community structure varied along a vegetational gradient in the Ulan Buh Desert (Gobi Desert). Sampling was done with pitfall traps in three sites with different vegetation cover. Species abundance distributions were fitted by the geometric series model, which expresses the “niche pre-emption” hypothesis. Community structure was investigated using different measures of diversity (number of species, Margaleff richness and Shannon-Weaner index), dominance (Simpson and Berger-Parker indexes) and evenness (Pielou’s index). The observed tenebrionid species richness was similar to that known from other Gobi Desert sites. The three investigated sites have similar species-abundance patterns, but the most dominant species varied among them. This suggests that the local environment operates a filtering action on the same basic fauna, allowing different species to dominate under different conditions. Overall, the highest total abundance was observed in the true desert site, however this site had a community structure similar to that observed in the site with more vegetation. By contrast, the investigated site with intermediate conditions showed a higher diversity and evenness, and a lower dominance. Thus, intermediate conditions of plant cover favour tenebrionid diversity, whereas a dense cover or a very sparse cover increases the dominance.

scholarly journals Range-wide spatial mapping reveals convergent character displacement of bird song

2019 ◽  
Vol 286 (1902) ◽  
pp. 20190443 ◽  
Author(s):  
Alexander N. G. Kirschel ◽  
Nathalie Seddon ◽  
Joseph A. Tobias
Keyword(s):  
Spatial Patterns ◽  
Evolutionary Biology ◽  
Environmental Gradients ◽  
Empirical Studies ◽  
Remote Sensing Data ◽  
Character Displacement ◽  
Similar Species ◽  
Interspecific Territoriality ◽  
Coexisting Species

A long-held view in evolutionary biology is that character displacement generates divergent phenotypes in closely related coexisting species to avoid the costs of hybridization or ecological competition, whereas an alternative possibility is that signals of dominance or aggression may instead converge to facilitate coexistence among ecological competitors. Although this counterintuitive process—termed convergent agonistic character displacement—is supported by recent theoretical and empirical studies, the extent to which it drives spatial patterns of trait evolution at continental scales remains unclear. By modelling the variation in song structure of two ecologically similar species of Hypocnemis antbird across western Amazonia, we show that their territorial signals converge such that trait similarity peaks in the sympatric zone, where intense interspecific territoriality between these taxa has previously been demonstrated. We also use remote sensing data to show that signal convergence is not explained by environmental gradients and is thus unlikely to evolve by sensory drive (i.e. acoustic adaptation to the sound transmission properties of habitats). Our results suggest that agonistic character displacement driven by interspecific competition can generate spatial patterns opposite to those predicted by classic character displacement theory, and highlight the potential role of social selection in shaping geographical variation in signal phenotypes of ecological competitors.

scholarly journals The Use of DNA Barcoding to Assess Phylogenetic β-Diversity in Mid-Subtropical Evergreen Broad-Leaved Forests of China

Forests ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 923
Author(s):  
Liu ◽  
Liu ◽  
Ge ◽  
Huang ◽  
Zhou ◽  
...  
Keyword(s):  
Phylogenetic Diversity ◽  
Environmental Gradients ◽  
Environmental Filtering ◽  
Nuclear Region ◽  
Dna Barcodes ◽  
Subtropical Forests ◽  
Construction Methods ◽  
Β Diversity ◽  
Nuclear Its ◽  
Analysis Of Variation

The application of quantifying phylogenetic information into measures of forest β-diversity is increasing for investigating the underlying drivers of community assembly along environmental gradients. In terms of assessing evolutionary inferences of community processes, a variety of plant DNA barcodes has been widely used in phylogenetic diversity measurements. However, relatively few studies have evaluated the effectiveness of DNA barcodes with using nuclear region in estimating phylogenetic β-diversity, particularly for communities in tropical or subtropical forests. In this study, we employed DNA barcodes combing with the nuclear region to construct the community phylogeny and examined the patterns of phylogenetic β-diversity of three mid-subtropical evergreen broad-leaved forests (EBLFs) in South China. Three phylogenetic construction methods were performed, including a Phylomatic-generated tree and two ML trees based on the combination of rbcL +matK +ITS with or without a constrained tree. Our results showed that the DNA barcodes including nuclear ITS constructed a highly resolved phylogenetic tree, but the application of a constrained tree had little influence on estimation of phylogenetic diversity metrics (mean pairwise distances and mean nearest taxon distances) based on branch lengths. Using both metrics and their standardized effect size metrics, we found that the patterns of phylogenetic β-diversity in mid-subtropical forests were non-random. There was a slight decline of phylogenetic β-diversity with increasing latitudes, but no trend was found along the altitude gradient. According to the analysis of variation partition, both environmental filtering and dispersion limitation could explain the variation of phylogenetic dissimilarity between communities in mid-subtropical EBLFs of China. Our results highlight the importance of neutrality and the niche conservatism in structuring the patterns of species diversity in subtropical woody communities.

scholarly journals Large-scale patterns in the community structure and biodiversity of freeliving nematodes in the Bohai Sea, China

2001 ◽  
Vol 81 (5) ◽  
pp. 755-763 ◽  
Author(s):  
Y. Guo ◽  
P.J. Somerfield ◽  
R.M. Warwick ◽  
Z. Zhang
Keyword(s):  
Community Structure ◽  
Environmental Variables ◽  
Large Scale ◽  
Bohai Sea ◽  
Yellow River ◽  
River Mouth ◽  
Sediment Surface ◽  
Similar Species ◽  
Taxonomic Distinctness ◽  
The Bohai Sea

Freeliving marine nematodes were sampled on two occasions from an extensive grid of 20 stations in the Bohai Sea and its approaches. Differences within stations between sampling periods were small, resulting from small changes in abundance of dominant species. Differences between stations were significant, and were used to cluster stations into groups with similar species composition. These station groupings revealed a weak faunal gradient leading from the mouth of the Huanghe (Yellow River) to the Bohai Strait. Analyses relating faunal composition to environmental variables showed that there were significant differences in environmental variables between faunally-defined groups of stations. The variables most closely correlated with community structure were silt/clay and sand, depth, phaeopigment concentrations below the sediment surface, organic content and arsenic. These reflect natural processes within the Bohai Sea. A suite of univariate measures were related to distance from the river mouth, with a major discontinuity about 120 km into the Bohai Sea. Comparison of values of the biodiversity measures average taxonomic distinctness (Δ+) and variation in taxonomic distinctness (Λ+) suggest that the meiobenthos of the Bohai Sea as a whole is not under major pollution stress.

Sign in / Sign up

Export Citation Format

Share Document