Supporting Datasets for Life History Responses to Temperature and Seasonality Mediate Ectotherm Consumer-Resource Dynamics Under Climate Warming

  We surveyed populations of the damselfly E. annexum, and their prey zooplankton, to characterize seasonal changes in population abundances and biomass. We sampled three ponds of Lux Arbor Reserve, southwestern Michigan, USA, twice per month from May 2016 to November 2016, and again from April to May 2017. We recorded surface water temperatures at hourly intervals using HOBO pendant temperature loggers (UA-001-64, Onset Corporation, Bourne, MA, USA). We collected E. annexum at three locations within each pond by sweeping a D-frame aquatic dip net (500 mm mesh, Wildco Wildlife Supply Co., Yulee, FL, USA) through macrophyte beds along a 1-m transect parallel to shore at depths of 0.25-0.75 m. We sampled zooplankton using vertical zooplankton net tows (153 mm mesh, 20.32 cm diameter opening, Wildco Wildlife Supply Co.) at water depths of 0.25 to 1.0 m and froze samples for estimation of biomass. We monitored adult emergence of E. annexum from May to June 2017 using floating insect emergence traps. We collected and counted all damselflies every other day and identified males to species.  We identified E. annexum under a dissecting microscope (Stemi 508, Zeiss, USA) using published and online taxonomic guides. We tracked growth in body size of E. annexum by measuring the head capsule width of the first 20 individuals in each sample with an ocular micrometer (± 0.1 mm) and drying and weighing (± 0.01 mg) at least ten individuals of each probable instar. We estimated zooplankton biomass by sorting individuals of the Orders Diptera, Cladocera, Copepoda, and Rotifera from each sample under a dissecting microscope, drying them for 24 hours at 60°C, and weighing them (± 0.01 mg). We then calculated zooplankton biomass per liter sampled as: (dry weight)/(volume filtered by the plankton net). We estimated the volume filtered as: pi * net radius2 * sample depth * filtering efficiency, assuming filtering efficiency of 0.5. The datasets presented here represent unprocessed data with measurements from three ponds, including hourly temperature, damselfy counts and head capsule widths, and zooplankton weights from biweekly pond sampling. These data also include counts of emerging adult damselflies. The included R script ("Insect_abundances_1_30_23.R") processes these data files to characterize seasonal changes in damselfly body sizes, abundances, zooplankton biomass, abundances of emerging adult damselflies, and pond temperature seasonality. The R script produces Figure S1, and the estimates of K, Smin, Smax, Tav, Tamp, and the phase shift of the temperature function for Table S1, of the manuscript supplementary materials.  </p

Trophic tangles through time? Opposing direct and indirect effects of an invasive omnivore on stream ecosystem processes.

Omnivores can impact ecosystems via opposing direct or indirect effects. For example, omnivores that feed on herbivores and plants could either increase plant biomass due to the removal of herbivores or decrease plant biomass due to direct consumption. Thus, empirical quantification of the relative importance of direct and indirect impacts of omnivores is needed, especially the impacts of invasive omnivores. Here we investigated how an invasive omnivore (signal crayfish, Pacifastacus leniusculus) impacts stream ecosystems. First, we performed a large-scale experiment to examine the short-term (three month) direct and indirect impacts of crayfish on a stream food web. Second, we performed a comparative study of un-invaded areas and areas invaded 90 years ago to examine whether patterns from the experiment scaled up to longer time frames. In the experiment, crayfish increased leaf litter breakdown rate, decreased the abundance and biomass of other benthic invertebrates, and increased algal production. Thus, crayfish controlled detritus via direct consumption and likely drove a trophic cascade through predation on grazers. Consistent with the experiment, the comparative study also found that benthic invertebrate biomass decreased with crayfish. However, contrary to the experiment, crayfish presence was not significantly associated with higher leaf litter breakdown in the comparative study. We posit that during invasion, generalist crayfish replace the more specialized native detritivores (caddisflies), thereby leading to little long-term change in net detrital breakdown. A feeding experiment revealed that these native detritivores and the crayfish were both effective consumers of detritus. Thus, the impacts of omnivores represent a temporally-shifting interplay between direct and indirect effects that can control basal resources

Results from the experimental manipulation of crayfish densities.

<p>Each point represents a study pool. Total non-crayfish benthic invertebrate abundance corresponds to open white symbols and gray confidence interval while total non-crayfish biomass corresponds to the gray symbols and darker gray confidence intervals. Benthic invertebrates were negatively associated with crayfish for both non-crayfish benthic invertebrate numerical density (log (invertebrates m⁻²) = −0.087 * crayfish +3.38, <i>R²</i> = 0.59, <i>P</i><0.001) and biomass density (log (invertebrates m⁻²) = −0.046 * crayfish +2.82; <i>R²</i> = 0.33, <i>P</i> = 0.02). The solid lines denote these best fit linear model and the polygons indicate 95% confidence intervals. Note data are log-transformed.</p

Invertebrate communities and the comparative study of crayfish.

<p>Each point represents the average for a study pool. (a) Invertebrate biomass (average biomass for coarse mesh leaf litter bags) as a function of crayfish density. Shown is the best fit exponential decay relationship (invertebrate biomass = 42.7 * exp (crayfish * −3.2)). (b). Average individual invertebrate mass as a function of crayfish density. White symbols with the solid line are caddisflies (Tricoptera), corresponding to the left y-axis and gray symbols with the dashed line correspond to stoneflies (Plecoptera), corresponding to the right y-axis. If pools did not contain any individuals, these points are not shown.</p

Ecosystem processes in the comparative study.

<p>Each point represents a different study pool. (a). Rate of algal accrual on elevated tiles. The gray polygon denotes the 95% confidence interval. (b). Rate of breakdown of leaves. Also shown in this panel in the open polygon and dashed line is the prediction interval and predicted line from the 2008 experimental relationship between leaf litter breakdown rate and crayfish.</p

Schemata of the direct and indirect effects of crayfish (<i>P. leniusculus</i>).

<p>Direct effects are solid arrows, indirect effects are dashed arrows. The direction of the impact is shown in parenthesis.</p

Ecosystem processes and crayfish density manipulation.

<p>Each point represents a study pool. (a). Rate of algal accrual on elevated tiles. Algal accrual was negatively associated with crayfish density (algal accrual rate = 0.13 * crayfish +1.05; <i>R²</i> = 0.29, <i>P</i> = 0.03). (b). Rate of breakdown of leaves. A higher k value corresponds to more rapid breakdown and k was higher at higher crayfish densities (k = 0.010 * crayfish +0.036; <i>R²</i> = 0.64, <i>P</i> = 0.0002). For both relationships, the solid line denotes the best fit linear model and the gray polygon indicates the 95% confidence interval.</p

Consumption of leaf litter by three detritivores: the invasive signal crayfish (<i>P. leniusculus</i>), and the native caddisflies <i>Lepidostoma spp</i>. and <i>Psychoglypha</i> spp. (order: Tricoptera) in feeding trials.

<p>Individual mass is dry mass of the individual after the experiment. Consumption is the amount of leaves eaten, normalized by background loss rate (see Methods). Also shown is the best fit allometric relationship.</p

The global EPTO database:worldwide occurrences of aquatic insects

Abstract Motivation: Aquatic insects comprise 64% of freshwater animal diversity and are widely used as bioindicators to assess water quality impairment and freshwater ecosystem health, as well as to test ecological hypotheses. Despite their importance, a comprehensive, global database of aquatic insect occurrences for mapping freshwater biodiversity in macroecological studies and applied freshwater research is missing. We aim to fill this gap and present the Global EPTO Database, which includes worldwide geo-referenced aquatic insect occurrence records for four major taxa groups: Ephemeroptera, Plecoptera, Trichoptera and Odonata (EPTO). Main type of variables contained: A total of 8,368,467 occurrence records globally, of which 8,319,689 (99%) are publicly available. The records are attributed to the corresponding drainage basin and sub-catchment based on the Hydrography90m dataset and are accompanied by the elevation value, the freshwater ecoregion and the protection status of their location. Spatial location and grain: The database covers the global extent, with 86% of the observation records having coordinates with at least four decimal digits (11.1 m precision at the equator) in the World Geodetic System 1984 (WGS84) coordinate reference system. Time period and grain: Sampling years span from 1951 to 2021. Ninety-nine percent of the records have information on the year of the observation, 95% on the year and month, while 94% have a complete date. In the case of seven sub-datasets, exact dates can be retrieved upon communication with the data contributors. Major taxa and level of measurement: Ephemeroptera, Plecoptera, Trichoptera and Odonata, standardized at the genus taxonomic level. We provide species names for 7,727,980 (93%) records without further taxonomic verification. Software format: The entire tab-separated value (.csv) database can be downloaded and visualized at https://glowabio.org/project/epto_database/. Fifty individual datasets are also available at https://fred.igb-berlin.de, while six datasets have restricted access. For the latter, we share metadata and the contact details of the authors