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Stressors, Food Web Connectivity, and Stability

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Wide banner of the study system Raw photo location: 20200729_145101.jpg Photo Credit: Symons Lab, UCI

One sentence on impact: In three days, we probe how interacting stressors rewire aquatic food-web connections and highlight stability signals that managers can act on.

Project brief (PDF) · View shared code · Explore data

About this site: This is a public, in-progress record of a 3-day project at the Innovation Summit. Edit everything here in your browser: open a file → pencil icon → Commit changes.

How to use this page (for the team)

  • Edit this file: docs/index.md → ✎ → change text → Commit changes.
  • Add images: upload to docs/assets/ and reference like assets/your_file.png.
  • Keep text short and visuals first. Think “slide captions,” not essays.

Day 1 — Define & Explore

Focus: questions, hypotheses, context; add at least one visual (photo of whiteboard/notes).

Our product 📣

  • Future publication
  • Conceptual progress towards an ESIIL Working Group application

Our question(s) 📣

  • How do multiple stressors impact food web connectivity in aquatic systems, and at what threshold of connectivity do we pass a tipping point?
  • Can food web connectivity be used as a predictor of tipping points?
  • Does relative abundance at each trophic level signal tipping points?

Hypotheses / intentions [Optional: probably not relevant if you are creating an educational tool]

  • If the number of food web connections approximates stability, then loss of some number of connections over a threshold will result in a significantly different food web composition.
  • Addition of multiple stressors will lead to a switch in trophic cascade structure (bottom-up versus top-down systems).
  • Addition of multiple stressors will shift food webs to contain a higher proportion of generalist species.

Why this matters (the “upshot”) 📣

Aquatic places have a lot of value - food, recreation, biodiversity, and more. Freshwater lakes are under threat from multiple stressors including changing temperatures, pH, nutrients, invaisve species, and human impact, which threaten those values.

Inspirations (papers, datasets, tools)

  • Vermont Department of Environmental Conservation/EPA water quality datasets: Lake Champlain data

Field notes / visuals

Whiteboard brainstorm (replace this) Raw photo location: day1_whiteboard.jpg Initial whiteboard brainstorm of a basic foodweb

Different perspectives: Briefly capture disagreements or alternate framings. These can unlock innovation.

Day 2 — Data & Methods

Focus: what we’re testing and building; show a first visual (plot/map/screenshot/GIF).

Data sources we’re exploring 📣

Lake Champlain Monitoring Sites Raw photo location: LakeChamplainMap.png

  • Vermont Department of Environmental Conservation/EPA water quality datasets: Lake Champlain data Physical, chemical, and biological observations including nutrients, temperature, pH, dissolved oxygen, and biological species -EPA Great Lakes Data repository GLENDA: [Great Lakes Data Repository] (https://cdxapps.epa.gov/cdx-glenda/action/querytool/querySystem)

Methods / technologies we’re testing 📣

  • Parameterize a simulated food web using observed data from Lake Champlain.
  • In simulated model, introduce stressors such as changes to temperature, pollution (e.g., nutrients), invasive species, etc.
  • Calculate food web metrics such as connectivity, number of nodes, stability, etc. before and after introduction of stressors.
  • Determine if and where thresholds exist before food web metrics display food web collapse.

Challenges identified

Data gaps / quality issues:

  1. Site IDs don't seem to match to consistent locations.
  2. Site IDs are differen't between the Vermont DEC website and the EPA API (where we actually stream data from), making it difficult to get a handle on what sites we are looking at.
  3. Zooplankton is missing from the Lake Champlain dataset, which are crucial taxa to include in a freshwater food web.

Method limitations / compute constraints

  1. How do we make a basic, but also realistic, simulated food web to test effects of stressors?

Open questions we need to decide on

  1. How complex of a food web do we simulate?
  2. Which stressors do we include in the system?
  3. Do we expand outside of Lake Champlain? If so, where do we find those data?

Visuals

Static figure

Various water quality metrics Raw photo location: lc_water_quality.png Figure 1. Snapshot showing water quality over time at a pilot station.

Missisquoi Bay Water Quality over time Raw photo location: lc_water_quality.png Figure 2. Water quality over time at a shallow water station. Vertical red dashed lines indicate biological invasions.

Simple food web specific to Lake Camplain Raw photo location: lc_water_quality.png Figure 3. Simple food web relevant to most freshwater lake systems with common Lake Champlain invasive species.

Moderately complex food web specific to Lake Champlain Raw photo location: lc_water_quality.png Figure 4. Slightly more complex food web specific to Lake Camplain and many other freshwater lakes. Year of introduction of invasive species labeled in parantheses.

Interactive map (iframe)

View Larger Map

Final Share Out — Insights & Sharing

Team photo at start of Day 3 Raw photo location: team_photo.jpg

Findings at a glance 📣

  • Freshwater lakes provide important values to humans and ecosystems. It is imperative that resource managers understand food webs and the threats that can alter them.
  • Lake Champlain has multiple stressors acting on food webs including warming temperatures, nutrient inputs, and invasive species introductions.
  • Invasive species invasions can be detected from figures
  • Scale matters! E.g., phosphorus varies at different depths.

What’s next? 📣

  • Aquire more relevant data (e.g., zooplankton data from collaborator)
  • Harmonize data
  • Identify all stressors that affect Lake Champlain
  • Refine scope
  • Develop ESIIL Working Group application
  • Future publication!

Team

Name Role Affiliation GitHub
Dr. Matt Bitters TBD CIRES, CU Boulder @matthewbitters
Dr. Alyssa Gleichsner TBD SUNY Plattsburgh @ParasiticProf; @agleichs
Dr. Harrison Hartle TBD Santa Fe Institute @hartle
Evan Fiorenza TBD UC Irvine @evanfiorenza
Aruni Kadawatha TBD Case Western Reserve University @AruniD0219
Ruby Krasnow TBD University of Maine @rmk118

Storage

Code Keep shared scripts, notebooks, and utilities in the code/ directory. Document how to run them in a README or within the files so teammates and visitors can reproduce your workflow.

Documentation Use the docs/ folder to publish project updates on this site. Longer internal notes can live in documentation/; summarize key takeaways here so the public story stays current.

Cite & reuse

If you use these materials, please cite:

Innovation Summit Group 4. (2025). Stressors, Food Web Connectivity, and Stability. GitHub. https://github.com/CU-ESIIL/stressors-food-web-connectivity-stability-innovation-summit-2025__4

License: CC-BY-4.0 unless noted. See dataset licenses on the Data page.