DOI: 10.5061/dryad.79hb8
title: Data from: Predators regulate prey species sorting and spatial distribution in microbial landscapes

description: 1. The role of predation in determining the metacommunity assembly model
 of prey communities is understudied relative to that of interspecific
 competition among prey. Previous work on metacommunity dynamics of
 competing species has shown that sorting by habitat patch type and spatial
 patterning can be affected by disturbances. 2. Microcosms offer a useful
 model system to test the effect of multi-trophic interactions and
 disturbance on metacommunity dynamics. Here, we investigated the potential
 role of predators in enhancing or disrupting sorting and spatial pattern
 among prey in experimental landscapes. 3. We exposed multi-trophic protist
 microcosm landscapes with one predator, two competing prey, two patch
 resource types, and localized dispersal to three disturbance regimes
 (none, low, and high). Then, we used variation partitioning and spatial
 clustering analysis to analyze the results. 4. In contrast with previous
 experiments that did not manipulate predators, we found that patch type
 did not structure prey communities very well. Instead, we found that it
 was the distribution of the predator that most strongly predicted the
 composition of the prey community. 5. The predator impacted species
 sorting by 1) preferentially consuming one prey, thereby acting as a
 strong local environmental driver, and by 2) indirectly magnifying the
 impact of patch food resources on the less preferred prey. The predator
 also enhanced spatial signal in the prey community because of its limited
 dispersal. Our results indicate that predators can strongly influence prey
 species sorting and spatial patterning in metacommunities in ways that
 would otherwise be attributed to stochastic effects, such as dispersal
 limitation or demographic drift. Therefore, whenever possible, predators
 should be explicitly included as separate explanatory factors in variation
 partitioning analyses.
description: Repeated-measures
 abundance of protists speciesThis data file contains
 the abundances of the three protist species we used in the experiment
 described in the paper (Colpidium, Paramecium, and Dinidium). Rows are
 sampling units (Petri dishes). Columns are disturbance treatments (no,
 intermediate, and high), resource (seed, no_seed), and week measured.
 Column headings should be self explanatory. Missing values appear as blank
 spaces.species.all_annotated_w_environment.csvProtist species occupancyRepeated-measures abundance and occupancy of protist species manipulated in the experiment per disturbance treatment. Measurements start at week 2.species_occupancy.csvXY coordinates for spatial modellingThis file is just an arbitrary x-y coordinate coding to designate each Petri dish. It was used for the spatial modelling.space.csvEcosystem functioningThis file contains the two ecosystem properties we measured (NH4 and Chlorophyll) in weeks 4, 5, and 6 of the experiment, along with the respective Paramecium abundance. Figure S2 can be made using these data.ecofunk_raw.xlsxSpatial point patternThis is the data we used for calculating the Kcross statistics in the spatial point pattern section of the paper.kcross_all.csv