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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 📣

  • Publication

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)

Field notes / visuals

Whiteboard brainstorm (replace this) Raw photo location: day1_whiteboard.jpg Caption: What this shows and why it’s useful today.

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 📣

  • EPA National Aquatic Resource Surveys (2019–2020) — trophic state, nutrient loading, and stressor indicators across U.S. freshwater sites. We will subset to basins with existing food-web observations.

Pattern revealed during exploration Raw photo location: explore_data_plot.png Snapshot showing nutrient stress classes vs. observed connectivity metrics for pilot basins.

  • USGS NWIS streamflow and temperature — daily discharge and thermal anomalies that help characterize hydrologic stress.
  • mangal food-web records — baseline interaction matrices for systems with similar species assemblages, used to test transferability of connectivity metrics.

Methods / technologies we’re testing 📣

  • Network analysis with NetworkX and igraph to derive modularity, redundancy, and robustness indicators under different stressor combinations.
  • Gradient boosted trees for predicting stability responses from combined stressor intensities.
  • Interactive geospatial dashboards built with kepler.gl/folium to surface hotspots for partner discussion.

Challenges identified

  • Aligning species/taxa naming conventions across datasets and the mangal database.
  • Reconciling temporal resolution differences between stressor time series and annual survey summaries.
  • Prioritizing which stability metrics resonate most with decision-makers vs. being academically interesting.

Visuals

Static figure

Early pattern we’re seeing Raw photo location: figure1.png Figure 1. Preliminary comparison of connectivity redundancy vs. combined thermal and nutrient stress classes.

Animated change (GIF)

Seasonal/temporal change animation Raw photo location: change.gif Figure 2. Animated exploration of seasonal stressor stacking and resulting shifts in trophic exchange.

Interactive map (iframe)

Open full map

If an embed doesn’t load, put the normal link directly under it.

Final Share Out — Insights & Sharing

Focus: synthesis; highlight 2–3 visuals that tell the story; keep text crisp. Practice a 2-minute walkthrough of the homepage 📣: Why → Questions → Data/Methods → Findings → Next.

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

Findings at a glance 📣

  • Combined thermal and nutrient stress reduced connectivity redundancy by ~35% in high-altitude basins.
  • Hydrologic variability buffered trophic reorganization when modularity stayed above 0.4.
  • Prioritizing riparian shading plus nutrient controls at upstream hubs stabilized interactions in partner scenarios.

Visuals that tell the story 📣

Lead conclusion visual placeholder Raw photo location: fire_hull.png Visual 1. Heatmap of redundancy vs. combined stressor intensity highlighting the most vulnerable network nodes.

Supporting panels for key insights Raw photo location: hull_panels.png Visual 2. Panel of time-synced stressor trajectories and network metrics for two contrasting watersheds.

Complementary result figure placeholder Raw photo location: main_result.png Visual 3. Scenario comparison showing stability improvements under proposed mitigation actions.

What’s next? 📣

  • Immediate follow-ups: finalize reproducible notebooks, confirm data citations, and prep repository README for partners.
  • One more week/month: expand analysis to additional basins and incorporate species-trait modifiers for stress tolerance.
  • Share next with: Innovation Summit mentors, watershed collaborative leads, and the ESIIL cyberinfrastructure team.
Project brief PDF
Read the brief 		View shared code
View code 		Explore data
Explore data

Team

Name Role Contact GitHub
Add name Lead & coordination your.email@example.org @github-handle
Add name Data & synthesis teammate.email@example.org @github-handle
Add name Modeling & visualization teammate.email@example.org @github-handle
Add name Communications & partnerships teammate.email@example.org @github-handle

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.