DOI: 10.5061/dryad.866t1g1zj
title: Multiple stressors simplify freshwater food webs

description: Globally, freshwater ecosystems are threatened by multiple stressors, yet
 our knowledge of how they combine to regulate the structure and energy
 dynamics of food webs remains scant. To address this knowledge gap, we
 conducted a large-scale mesocosm experiment to quantify the single and
 combined effects of three common anthropogenic stressors, including
 warming, increased nutrient loading, and insecticide pollution, on the
 network structure and energetic processes of shallow lake food webs. We
 identified both antagonistic and synergistic interactive effects on
 aquatic food webs. Overall, multiple stressors simplified the food web,
 elongated energy transfer pathways, and shifted energy flow from benthic
 to more pelagic pathways. This increased the risk of a regime shift from a
 clear-water state dominated by submerged macrophytes to a turbid state
 dominated by phytoplankton. Our study highlights how multiple
 anthropogenic stressors can interactively disrupt food webs, with
 implications for understanding and managing these ecosystems in a changing
 world.
description: Collecting from the experiment
description: # **Title: Multiple stressors simplify freshwater food webs**  Access this
 dataset on Dryad (doi:10.5061/dryad.866t1g1zj)  We have conducted a
 large-scale mesocosm experiment to quantify the single and combined
 effects of three common anthropogenic stressors, including warming,
 increased nutrient loading, and insecticide pollution, on the network
 structure and energetic processes of shallow lake food webs. We
 constructed similar food webs at the beginning of the experiment,
 monitored water quality and biological parameters during the experiment
 and quantified food web components at the end of the experiment. We have
 submitted our raw data water quality and biological parameters during the
 experiment (Parameters_over_time.xlsx), biomass and abundance of food web
 components at the end of the experiment (Food_web_components.xlsx). A
 multilevel metadata includes food web meta data for each pond and sum of
 the six ponds of each treatment: (FoodwebMetadata.zip). R scripts
 (MesocosmFinal.R; TimeSeries.R; Interaction-null-models.R;
 FoodwebProperties.R)  **Food_web_components.xlsx**: The file includes the
 biomass and abundance of all food web components at the end of the
 experiment. This file consists of two sheets, the first sheet is the code
 explanation for the data of the second sheet. This data is the input data
 for R codes: MesocosmFinal.R and Interaction-null-models.R. •        
 Pond: Code for each mesocosm pond •         Temp: Warming treatment, 0
 indicates ambient, W indicates heated •         Eutroph: Nutrient loading
 treatment, 0 indicates no addtion of nutrients, N indicates nitrogen and
 phosphorus addtion •         Insecticide: Insecticide treatment, 0
 indicates no addition of insecticide, I indicates insecticide addtion
 •         Code: Treatment code for each pond •         Hydrilla : Biomass
 of Potamogeton cripus at the end of the experiment (g per mesocosm)
 •         P.crispus: Biomass of Hydrilla verticillata at the end of the
 experiment (g per mesocosm) •         Carp_B: Biomass of the crucian carp
 Carassius auratus auratus at the end of the experiment (g per mesocosm)
 •         Carp_N: Number of the crucian carp Carassius auratus auratus at
 the end of the experiment •         Rhodeus_B: Biomass of the bitterling
 Rhodeus sinensis at the end of the experiment (g per mesocosm) •        
 Rhodeus_N: Number of the bitterling Rhodeus sinensis at the end of the
 experiment •         Shrimp_B: Biomass of the shrimp Macrobrachium
 nipponense at the end of the experiment (g per mesocosm) •        
 Shrimp_N: Number of the shrimp Macrobrachium nipponense at the end of the
 experiment •         Predator_Species: Number of the predator species,
 including fish and shrimp •         Bellamya_N : Number of the snail
 Bellamya aeruginosa at the end of the experiment •        
 Bellamya_B:      Biomass of the snail Bellamya aeruginosa at the end of
 the experiment (g per mesocosm) •         Radix_N: Number of the snail
 Radix swinhoei at the end of the experiment •         Radix_B: Biomass of
 the snail Radix swinhoei at the end of the experiment (g per mesocosm)
 •         Cladocera_A: Abundance of zooplankton Cladocera at the end of
 the experiment (ind. per mesocosm) •         Copepoda_A: Abundance of
 zooplankton Copepoda at the end of the experiment (ind. per mesocosm)
 •         Rotifers_A: Abundance of zooplankton Rotifers at the end of the
 experiment (ind. per mesocosm) •         Cladocera_B: Total biomass of
 zooplankton Cladocera at the end of the experiment (g per mesocosm)
 •         Copepoda_B: Total biomass of zooplankton Copepoda at the end of
 the experiment (g per mesocosm) •         Rotifers_B: Total biomass of
 zooplankton Rotifers at the end of the experiment (g per mesocosm)
 •         Oligochaeta_B: Total biomass of zoobenthos Oligochaeta at the
 end of the experiment (g per mesocosm) •         Oligochaeta_N: Abundance
 of zoobenthos Oligochaeta at the end of the experiment (ind. per mesocosm)
 •         Snail_Other_B: Total biomass of some other tiny snails at the
 end of the experiment (g per mesocosm) •         Snail_Other_N: Abundance
 of some other tiny snails at the end of the experiment (ind. per mesocosm)
 •         Insecta_B: Total biomass of insecta at the end of the experiment
 (g per mesocosm) •         Insecta_N: Abundance of insecta at the end of
 the experiment (ind. per mesocosm) •         Phytoplankton_B: Total
 biomass of phytoplankton at the end of the experiment (g per mesocosm)
 •         Phytoplankton_A: Total abundance of phytoplankton at the end of
 the experiment (ind. per mesocosm) •         Periphyton_B: Total biomass
 of periphyton at the end of the experiment (g per mesocosm) •        
 Periphyton_A: Total abundance of periphyton at the end of the experiment
 (ind. per mesocosm)   **Parameters_over_time.xlsx:** The file includes the
 background water quality and biological parameters which has measured
 during the experiment. This file consists of two sheets, the first sheet
 is the code explanation for the data of the second sheet. This data is the
 input data for R codes: TimeSeries.R. •         Pond: Code for each
 mesocosm pond •         Temp: Warming treatment, 0 indicates ambient, W
 indicates heated •         Eutroph:       Nutrient loading treatment, 0
 indicates no addtion of nutrients, N indicates nitrogen and phosphorus
 addtion •         Insecticide: Insecticide treatment, 0 indicates no
 addition of insecticide, I indicates insecticide addtion •         Code:
 Treatment code for each pond •         Julian: Julian day of the year
 •         Date: Date of each sampling day •         P.crispus: PVI of
 Potamogeton cripus •         Hydrilla : PVI of Hydrilla verticillata
 •         DO: Total dissolved oxygen concentration in the water column
 during the experiment (mg L-1) •         pH: pH in the water column in the
 water column during the experiment •         Conductivity: Conductivity in
 the water column during the experiment (µs cm-2) •         Turbidity:
 Water turbidity in each sampling day (NTU) •         TN: Total nitrogen
 concentration in the water column during the experiment (mg L-1) •        
 NH4: Ammonia nitrogen concentration in the water column during the
 experiment (mg L-1) •         NO3: Nitrate concentration in the water
 column during the experiment (mg L-1) •         TP: Total phosphorus
 concentration in the water column during the experiment (mg L-1) •        
 PO4: Phosphate concentration in the water column during the experiment (mg
 L-1) •         Phytoplankton: Chl a concentration of phytoplankton during
 the experiment (µg L-1) •         Periphyton: Chl a concentration of
 periphyton during the experiment (µg cm-2)  **FoodwebMetadata.zip**: This
 file includes food web meta data for each pond and sum of the six ponds of
 each treatment. For each web, including three CSV files: nodes.csv,
 properties.csv, and trophic.links.csv. These files are arranged in
 accordance to the input format of R package *cheddar*. nodes.csv •        
 node: each node represents a group of organisms in the food web •        
 category: the category of the organisms belongs •        
 functional.group: the functional group of the organisms belongs •        
 M: mean body biomass of each individual •         N: abundance of the
 organism •         Code: code number of each organism •        
 Totalbiomass: the total biomass of each group of organisms in the food web
  properties.csv •         title: the code of the pond •         M.units:
 unit of the mean body biomass •         N.units: unit of the abundance
 •         Temp: Warming treatment, 0 indicates ambient, W indicates heated
 •         Eutroph:       Nutrient loading treatment, 0 indicates no
 addtion of nutrients, N indicates nitrogen and phosphorus addition
 •         Pesticide: Insecticide treatment, 0 indicates no addition of
 insecticide, I indicates insecticide addition •         Pondnumber: the
 code number of the pond trophic.links.csv •         resource: the food for
 the consumer •         consumer: the consumer of the food
  **MesocosmFinal.R:** the input data is from Food_web_components.xlsx, and
 the file includes the codes for Fig. 1, Fig. S7, Fig. S9, Fig. S10 and
 Table S3.  **FoodwebProperties.R**: the input data is from
 FoodwebMetadata.zip, and the file includes the codes for food web
 structure traits and energy fluxes analysis for each food web, producing
 Fig. 2, Fig. 3, Fig. S4, Fig. S5, Fig. S6, Fig. S8, Fig. S11, Fig. S12 and
 Table 1.  **TimeSeries.R**: the input data is from
 Parameters_over_time.xlsx, and the file includes the codes for Fig. S13,
 Fig. S14, Fig. S15 and Table S4.  **Interaction-null-models.R**: the input
 data is from Food_web_components.xlsx, and the file includes the codes for
 Fig. S18 and Fig.S19.  Annotations are provided throughout the script
 through 1) library loading, 2) dataset loading and cleaning, 3) analyses,
 and 4) figure creation. If you have any problems with the data or codes,
 please feel free to contact Peiyu Zhang
 ([zhangpeiyu@ihb.ac.cn](mailto:zhangpeiyu@ihb.ac.cn)).