DOI: 10.5061/dryad.kd51c5b67
title: Diversity-stability cascade in pond plankton experiments

description: This collection of files consists of freshwater plankton biomass data from
 a laboratory microcosm experiment and an accompanying field mesocosm
 experiment in which we manipulated the presence of two heteropteran
 predators. In the laboratory experiment, we incubated 20 large microcosms
 with phytoplankton and zooplankton, fully crossing a 1x vs. 2x zooplankton
 density treatment with presence or absence of a single Notonecta undulata
 adult. Two of these microcosms were lost, resulting in data for 18 of
 these large microcosms. Concurrently, we incubated 20 small microcosms
 with a smaller amount of the same plankton mix, which similarly were fully
 crossed with the 1x vs. 2x zooplankton density treatment and presence or
 absence of a single Neoplea striola adult. After five days we collected
 the zooplankton remaining in each microcosm for identification and biomass
 estimation. For the field experiment, we established 20 mesocosms (cattle
 tanks) with phytoplankton and zooplankton collected from the same sources,
 and added six Notonecta adults to five mesocosms, 90 Neoplea adults to
 another five, and three Notonecta and 45 Neoplea to another five, with the
 remaining five mesocosms acting as no-predator controls. We sampled both
 the phytoplankton and zooplankton once per week for six weeks for
 identification and biomass estimation.
description: We collected phytoplankton, zooplankton, <em>Notonecta
 undulata</em> adults, and <em>Neoplea striola
 </em>adults from small freshwater bodies in Austin, TX.
 For the laboratory experiment, we filled 20 microcosms with 1.5 L
 of a mixture of the plankton, doubling the concentration of zooplankton in
 10 of the microcosms, and adding a <em>Notonecta
 </em>individual to half (5) of the microcosms with each zooplankton
 density. We then set up 20 smaller microcosms the same way, except with
 100 mL plankton mixture and <em>Neoplea </em>individuals.
 After 5 days we filtered and preserved the zooplankton. Finally we used
 microscopy to identify, count, and measure the zooplankton, allowing us to
 estimate the biomass of each zooplankton taxon in each microcosm using
 length-mass regressions. For the field experiment, we
 used the same plankton to establish pond communities in 20 cattle tanks at
 Brackenridge Field Laboratory in Austin, TX. We added 6
 <em>Notonecta </em>to 5 tanks, 90 <em>Neoplea
 </em>to 5 tanks, 3 <em>Notonecta </em>and 45
 <em>Neoplea </em>to 5 tanks, and added no insects to the other
 5. Then every week for 6 weeks we used tube samplers to take several whole
 water column zooplankton and phytoplankton samples from each tank and pool
 them into a composite zooplankton and a composite phytoplankton sample for
 each tank. We filtered and preserved the zooplankton samples, and
 preserved the phytoplankton samples. Then we used microscopy to identify,
 count, and measure the plankton, which allowed us to estimate the biomass
 of each zooplankton taxon in each sample using length-mass regressions,
 and to estimate the biovolume of each phytoplankton morphospecies in each
 sample using geometric formulas. See the corresponding
 article for more details.
description: Take note of the "ReadMe" file. Note that there are no
 missing values, and that all possible taxon-sample combinations are
 included in the datasets, marked with zero biomass/biovolume values when
 they were not found.