Metacommunity simulations for diatom assemblages residing in benthic cyanobacterial mats in Fryxell Basin in Taylor Valley in the McMurdo Dry Valleys, Antarctica

Here, we use MCSim, a spatially explicit metacommunity simulation package for R,
to test alternative hypotheses about the roles of dispersal and species sorting in
maintaining the biodiversity of diatom assemblages residing in black and orange mats
in Fryxell Basin in Taylor Valley in the McMurdo Dry Valleys of Antarctica. The
spatial distribution and patchiness of cyanobacterial mat habitats was characterized
by remote imagery of the Lake Fryxell sub-catchment in Taylor Valley collected in
January 2015. The available species pool for diatom metacommunity simulation
scenarios was informed by the Antarctic Freshwater Diatoms Database, maintained by
the McMurdo Dry Valleys Long Term Ecological Research program, representing samples
collected between January 1994 and January 2013. We used simulation outcomes to test
the plausibility of alternative community assembly hypotheses to explain empirically
observed patterns of freshwater diatom biodiversity in the long-term record. The
most plausible simulation scenarios suggest species sorting by environmental
filters, alone, was not sufficient to maintain biodiversity in the Fryxell Basin
diatom metacommunity. The most plausible scenarios included either (1) neutral
models with different immigration rates for diatoms in orange and black mats or (2)
species sorting by a relatively weak environmental filter, such that dispersal
dynamics also influenced diatom community assembly, but there was not such a strong
disparity in immigration rates between mat types. The results point to the
importance of dispersal for understanding current and future biodiversity patterns
for diatoms in this ecosystem, and more generally, provide further evidence that
metacommunity theory is a useful framework for testing hypotheses about microbial
community assembly. This dataset supports the paper: Sokol, E. Et al, 2020. Evaluating
Alternative Metacommunity Hypotheses for Diatoms in the McMurdo Dry Valleys
Using Simulations and Remote Sensing Data. Frontiers in Ecology and Evolution.
DOI: 10.3389/fevo.2020.521668. The dataset contains four objects: a) the
results of the simulation (zipped as one file), b) a manifest describing the
contents of that zip file, c) a release of the MCSim model (R code), and d)
ancillary inputs and code (zipped).