DOI: 10.5061/dryad.hx3ffbgtc
title: Contrasting effects of producer and consumer resource use efficiency on trophic asynchrony and stability of food web under multiple stressors

description: The ongoing global biodiversity loss caused by multi-stressors has raised
 concerns about the potential consequences of species extinctions on the
 functionality and stability of ecosystems. It has been widely recognized
 that biodiversity could stabilize the ecosystem by enhancing the
 asynchronous dynamics among species within a single trophic level.
 However, in natural multi-trophic ecosystems, asynchronous changes between
 trophic levels (trophic asynchrony) are expected to increase trophic
 mismatch and alter trophic interactions, which may consequently alter
 ecosystem stability. Under changeable environments, it is currently
 unclear how biodiversity in different trophic levels affects the stability
 of food web by changing the trophic interactions (represented by resource
 use efficiency, RUE) and trophic asynchrony, which is key to providing
 further insights into the biodiversity effects on ecosystem stability.
 Using a 6-month mesocosm experiment, we tested how
 multi-stressors—microplastics, eutrophication, dissolved organic carbon,
 and invasive fish—affected species richness and RUE of phytoplankton
 (producer) and zooplankton (consumer), subsequently influencing temporal
 stability of food web via altering the trophic asynchrony. Our results
 demonstrated that multi-stressors could shape ecosystem temporal stability
 through species richness-RUE-trophic asynchrony pathways, emphasizing the
 cascading impacts of multi-stressors on ecosystem functions and stability.
 Increasing species diversity of phytoplankton and zooplankton enhanced the
 RUE within that trophic level. However, greater producer diversity
 decreased RUE of consumers, probably due to an increase in inedible
 producer species. This suggests that benefits of biodiversity of producer
 could diminish functions at higher trophic levels. In addition,
 zooplankton RUE increased trophic asynchrony, whereas phytoplankton RUE
 decreased it. Crucially, trophic asynchrony stabilized phytoplankton and
 food web but destabilized zooplankton community, highlighting contrasting
 impacts of trophic asynchrony on stability across trophic levels. Our
 study showed that producer diversity may indirectly decrease the functions
 and stability of consumers under multiple stressors, which challenged the
 simplistic expectation that more diversity universally stabilized
 ecosystems. This study provided a new insight into the
 biodiversity-ecosystem stability relationships by highlighting the
 mediating roles of RUE and trophic asynchrony under realistic
 environmental change scenarios.
description: <strong>1.1. Experimental design</strong>
 Our research was conducted in the Mesocosm Control Experiment
 System at Chenggong Campus of Yunnan University (25.054058 N, 102.702144
 E) from July to November 2023. Forty plastic buckets (diameter 1.58m,
 height 1.45m) were randomly distributed in the experimental site. Each
 bottom of the plastic bucket was covered with 100 mm thick sediment from
 Dianchi Lake (24.800556 N, 102.671389 E). Each tank was filled with 10%
 Dianchi Lake water and 90% tap water. Each bucket was cultivated with an
 equal number of <em>Potamogeton maackianus</em>,
 <em>Vallisneria natans</em>, <em>Myriophyllum
 spicatum</em>, and <em>Hydrilla verticillata</em>.
 Following the planting, the mesocosms were maintained for a 2-month period
 to allow the plants to stabilize. We set up a control
 group (C) and seven treatment groups, including NP (nitrogen and
 phosphorus, by adding NaNO<sub>3</sub> and
 K<sub>2</sub>HPO<sub>4</sub> 2 mg
 L<sup>-1</sup> and 0.15 mg L<sup>-1</sup>
 respectively every two weeks), MP (microplastics, by adding high-density
 polyethylene 5 g), F (fish, by adding 20 <em>Pseudorasbora
 parva</em>, fishes were replenished daily based on the observed
 mortality), DOC (dissolved organic carbon, by adding mixture of 4:1 C
 molar ratio sodium humate
 (C<sub>9</sub>H<sub>8</sub>Na<sub>2</sub>O<sub>4</sub>) and fulvic acid (C<sub>14</sub>H<sub>12</sub>O<sub>8</sub>) 15 mg L<sup>-1</sup> every two weeks) and MP related treatments (MP+NP, MP+F, MP+DOC), with a total of 3 combinations. There were five replicates for each control or treatment groups, which were randomly assigned to forty water tanks. We collected phytoplankton and zooplankton once a month. Phytoplankton was collected from 1 liter of surface water and then 1.5 ml of concentrated Lugo’s solution was added to each bottle. We then concentrated the sample to 30~60 ml by siphoning after standing for 48 h. We employed 13# plankton nets (aperture size is 112 µm) to gather zooplankton from a 20-liter volume of surface water. Subsequently, the collected samples were transferred into 80 ml square bottles, wherein 2 ml of formaldehyde (Shanghai Wukai Biotechnology Co., LTD. in China) was added to fix the zooplankton. <strong>1.2. Laboratory analysis and microscopic examination</strong> Total nitrogen (TN) and total phosphorus (TP) in water were measured according to standard methods. Specifically, the samples were first digested with potassium persulfate (Sigma Aldrich, Germany) in a sterilized pot (GR85DA, Zealway Instrument Inc., America) at 120 ℃ for 30 minutes. For phytoplankton, 0.1 ml of concentrated solution was placed in the phytoplankton counting frame under microscopy at 200-400 magnification and each piece was counted 100 visual fields. Each sample was counted twice, and then the average value was calculated. The difference between each count should be within 15%. Finally, the calculation of density was based on the following formula: N=(A/A<sub>c</sub>)*(V<sub>w</sub>/V)**n where, <em>A</em> and <em>A<sub>c</sub></em> are counting frame area and counting area (mm<sup>2</sup>); <em>V<sub>w</sub></em> and <em>V</em> are the volume (ml) of concentrated solution and counting frame, respectively; n is the number of individuals. We then used <em>N</em> to calculate the phytoplankton biomass by standard methods. Zooplankton was counted using 5 ml counting boxes and 40 magnification (Olympus CX41) and the body length (mm) was measured using the mesh micrometer (scale of the mesh micrometer was 0.025 mm) for subsequent biomass calculations. The specific process was as follows: the biomass of crustacean zooplankton was calculated according to the empirical regression equation (<em>W = qL<sup>b</sup></em>) of body length (<em>L</em>) and weight (<em>W</em>). <strong>1.3. Calculation of species richness, RUE, trophic asynchrony and stability</strong> Zooplankton and phytoplankton species richness were calculated by the “specnumber” function of the “vegan” package. The RUE of phytoplankton for nitrogen or phosphorus (Phytoplankton RUE<sub>TN</sub> and RUE<sub>TP</sub>) was calculated as the ratio of phytoplankton biomass (mg L<sup>-1</sup>) to TN or TP (mg L<sup>-1</sup>), respectively, which was commonly used in previous studies. Zooplankton RUE was calculated as the ratio of zooplankton to phytoplankton biomass (mg L<sup>-1</sup>). We calculated the statistical metric of trophic asynchrony according to Eq (1). Stability of zooplankton, phytoplankton and food web were calculated according to Eq (2).    Trophic asynchrony =  1-(σ<sub>total</sub><sup>2</sup>)/(σ<sub>zooplankton</sub><sup>2</sup>+σ<sub>phytoplankton</sub><sup>2</sup>)                       Eq (1) where, σ<sub>total</sub> is the standard deviation of total biomass of zooplankton and phytoplankton. σ<sub>zooplankton</sub> and σ<sub>zooplankton</sub> are the standard deviation of zooplankton and phytoplankton biomass, respectively.           Stability =   u/σ                                                                                   Eq (2) where u and σ represent the mean and standard deviation of the total biomass of zooplankton, phytoplankton or the sum of zooplankton and phytoplankton, respectively. Earlier work highlighted that producer diversity was a key driver of whole-food-web stability and that its importance increased with trophic complexity. Consequently, it is reasonable to assign producers a relatively large weight rather than manually setting equal weights to zooplankton when assessing food web temporal stability, and using the total biomass to quantify temporal stability was already a common practice.
description: # Contrasting effects of producer and consumer resource use efficiency on
 trophic asynchrony and stability of food web under multiple stressors
 Dataset DOI:
 [10.5061/dryad.hx3ffbgtc](https://doi.org/10.5061/dryad.hx3ffbgtc) ##
 Description of the data and file structure This file contains all the
 mesocosmic experimental data used for mapping in the article. We conducted
 a six-month mesocosmic experiment at the Chenggong Campus of Yunnan
 University. The one named "Treatment" is listed as our
 experimental treatment. C, MP, NP, DOC, and F represent the control group,
 microplastics, eutrophication and dissolved organic carbon, and fish
 invasion treatment groups respectively; MP+NP, MP+DOC and MP+F are the
 interaction treatments related to MP. In the four columns of MP, NP, DOC
 and F, the applied treatment is marked as 1 and the unapplied treatment is
 set to 0. The stability (Stability of food web, Stability of zooplankton
 and Stability of phytoplankton) in the list is the ratio of the mean to
 the standard deviation of the community biomass in the time series
 (temporal stability). RUE_ZP represents the resource utilization
 efficiency of zooplankton. RUE_PP_TN and RUE_PP_TP are respectively the
 resource utilization efficiencies of phytoplankton for total nitrogen and
 total phosphorus. The "Tank" column represents the water tanks
 in our cosmic experiment system. ### Files and variables #### File:
 Plastic.csv **Description:**  ##### Variables * Treatment: C, MP, NP, DOC,
 and F represent the control group, microplastics, eutrophication and
 dissolved organic carbon, and fish invasion treatment groups respectively;
 MP+NP, MP+DOC and MP+F are the interaction treatments related to MP. *
 Tank: the water tanks in our cosmic experiment system. * MP: microplastics
 * NP: eutrophication * DOC: dissolved organic carbon * F: fish invasion *
 Trophic asynchrony: Trophic asynchrony * Stability of zooplankton:
 temporal stability of zooplankton * Stability of phytoplankton: temporal
 stability of phytoplankton * Stability of foodweb: temporal stability of
 food web * Zooplankton species richness: species richness of zooplankton *
 Phytoplankton species richness: species richness of phytoplankton *
 RUE_ZP: resource utilization efficiency of zooplankton * RUE_PP_TN:
 resource utilization efficiency of phytoplankton for nitrogen *
 RUE_PP_TP: resource utilization efficiency of phytoplankton for phosphorus
 ## Code/software R 4.3.0 ## Access information Other publicly accessible
 locations of the data: * None Data was derived from the following sources:
 * None