Diversity and morphological disparity of desmid assemblages in Central European peatlands

Abstract

Morphological disparity has increasingly been used as an alternative measure of biological diversity based on the shape features of organisms. In this study, we investigated the species diversity and morphological disparity of benthic Desmidiales in Central European peatland pools. The shape features of cells were determined using the 3-D elliptical Fourier analysis of their frontal and lateral views. The resulting morphospace was used to calculate the contributions of localities and species to the morphological variation. In addition, the disparity of samples and their average cell complexity (indicating intricacy of cell shapes) was evaluated. These data were related to species diversity data and to the abiotic factors. Species diversity was positively correlated with pH and conductivity. The low-pH localities generally supported a more variable species composition than did slightly acidic to neutral localities.Conversely, the total nitrogen concentrations of these areas negatively correlated with species diversity. Interestingly, partial morphological disparity (measuring the contribution of a sample to the overall morphological variation) did not correlate with species diversity. On the contrary, several mountain peat bog localities had high disparity values, irrespective of their rather low species diversity. In addition, several samples from minerotrophic fens with high diversity had average or low values of partial morphological disparity. These results indicate the relative importance of mountain peat bogs for the total morphological diversity of Desmidiales within the region that could not be ascertained solely from species diversity data. The inner morphological disparity of samples was highly correlated with their species diversity. Species of the genus Micrasterias, Hyalotheca dissiliens and Desmidium species had the highest partial morphological disparity, thus indicating their marginal position within the morphospace. Micrasterias and Euastrum species had the highest complexity values. The average cell complexity of individual samples did not correlate with their diversity or disparity; however, it was positively correlated with the levels of total nitrogen and phosphorus, and illustrates a pattern different from that arrived at by species diversity data.

The effects of aperiodic desiccation on the diversity of benthic desmid assemblages in a lowland peat bog

“…The procedure involves data on the width-to-thickness ratios of individual species for the approximation of the lateral views in biradiate desmids, and the calculation of the position of the third lobe using the position of landmarks along the outline in a frontal view in triradiate species. For examples of 3D outlines reconstructed by this method see Neustupa et al (2009). The size-standardised coordinates of the 286 landmarks placed in the frontal and lateral views of the cells were subjected to 3D elliptical Fourier analysis in EFA3D, ver.…”

“…The morphological disparity of a natural assemblage is acquired from the total shape variability of its species (Roy and Foote 1997). In this study, we used the 3D morphometric registration of desmid cells as a basis for 3D elliptical Fourier analysis according to Neustupa et al (2009). These morphometric data were also used for the estimation of cell sizes and the surface-to-volume (S:V) ratios of individual species, and, consequently, of the mean values of these indicators in individual samples.…”

The pH-related morphological variations of two acidophilic species of Desmidiales (Viridiplantae) isolated from a lowland peat bog, Czech Republic

“…Closterium striolatum-4.0 to 7.0, Euastrum binale var. gutwinskii-3.9 to 7.5, Penium cylindrus-4.5 to 6.8 and Tetmemorus laevis-3.8 to 7.0, (Růžička 1977(Růžička , 1981Negro et al 2003;Ceosel and Meesters 2007;Neustupa et al 2009). These very different H ?…”

Geometric morphometry of Phytophthora plurivora sporangia

“…Morphological disparity permits the investigation of shape variation at temporal (phylogenetic) scale and spatial scale (the realm of ecomorphology) (Ricklefs & Miles 1994). Disparity is considered a complement of biodiversity within the morphospace by detecting the changes in morphospace occupation patterns (Roy & Foote 1997, Roy et al 2001, Neige 2003, Neustupa et al 2009). …”