Pollinator Network Risk From Invasive Species

ISEF Category: Earth and Environmental Sciences

Subcategory: Environmental Effects on Ecosystems  ·  Difficulty: Advanced  ·  Setup: Home Setup  ·  Time: Full Year

The Hook

A single invasive plant can act like a new bully in a school cafeteria. It can pull in pollinators, crowd out natives, and quietly reshape who gets visited and who gets ignored. You can measure that shift with field observations and open biodiversity data. Then you can turn those observations into a network model that shows risk, not just counts.

What Is It?

This project asks how invasive species change the web of visits between flowers and pollinators. Think of a pollinator network like a social network, but for bees, butterflies, flies, and plants. Each visit creates a link. Some plants have many links. Others have only a few. When an invasive species enters the system, it can steal attention from native plants or change which pollinators stay in the area.

A bipartite network is a simple map with two groups, plants and pollinators. You connect the two groups when a pollinator visits a flower. Then you can measure which native plants sit near the center of the network and which ones are on the edge. Plants with fewer partners or weaker links may be more vulnerable if an invasive species starts taking over visits. iNaturalist can help you find local species, and transect observations can give you your own field data to compare with the community records.

Why This Is a Good Topic

This is a strong science fair topic because you can study a real ecological problem with clear variables and real data. You can compare sites with different invasive species pressure, then test whether native plant visit patterns shift. The project connects directly to pollinator decline, habitat change, and invasive-species management. You will learn field sampling, biodiversity data cleanup, and network analysis, all skills that matter in ecology research.

Research Questions

• How does invasive-species abundance affect the number of pollinator visits to native flowers?
• What is the effect of invasive plant cover on native plant network centrality?
• Does higher invasive-species presence reduce pollinator diversity on native transects?
• To what extent do sites with more invasive species show lower interaction evenness in pollinator networks?
• Which native plant species lose the most unique pollinator partners near invasive patches?
• How does flower abundance change the link between invasive pressure and native pollinator visits?

Basic Materials

• Field notebook or waterproof data sheets.
• Smartphone with iNaturalist installed.
• Camera or phone camera with geotagging enabled.
• Measuring tape or transect line.
• Plant and pollinator field guide for your region.
• Clipboard and pencils.
• GPS app or map app for site marking.
• Weather app or access to local weather records.
• Spreadsheet software such as Google Sheets or Excel.

Advanced Materials

• Higher-resolution camera or macro lens attachment.
• Handheld GPS unit for precise site mapping.
• Binoculars for distant pollinator observation.
• Portable weather meter for temperature, wind, and light.
• Student access to R or Python for network analysis.
• Database access for local herbarium or biodiversity records.
• ImageJ for image-based flower or cover estimates.
• Optional insect net, if your school and local rules allow it.

Software & Tools

• iNaturalist: Helps you identify species, log observations, and compare your records with community identifications.
• Google Sheets: Organizes transect data, visit counts, and site-level invasive cover.
• R: Builds bipartite networks, calculates centrality, and tests relationships between variables.
• Python: Cleans observation data and automates graph analysis if you prefer code.
• Gephi: Visualizes plant-pollinator networks so you can compare site structure clearly.

Experiment Steps

1. Define the local ecosystem you will study and choose sites that differ in invasive-species pressure.
2. Decide how you will measure invasive abundance, native flower availability, and pollinator visits at each site.
3. Build a clean data system that matches each visit record to a plant species, a pollinator group, and a location.
4. Plan a network structure so each plant-pollinator pair becomes one interaction link you can compare across sites.
5. Choose the metrics that matter most, such as degree, centrality, connectance, and interaction evenness.
6. Design a comparison that tests whether invasive pressure predicts weaker native connections after accounting for flower abundance and site conditions.

Common Pitfalls

• Counting every flying insect as a pollinator, which inflates visit totals and weakens your network data.
• Mixing up plant identity across sites, which creates fake links in the bipartite model.
• Sampling only one sunny afternoon per site, which makes weather effects look like invasion effects.
• Using iNaturalist records without checking observation quality, which can add wrong species names or missing locations.
• Ignoring flower abundance, which can make a rare native look vulnerable only because it had fewer blooms.

What Makes This Competitive

A competitive version of this project goes beyond simple before-and-after counts. You can compare multiple sites, control for flower abundance, and test whether invasive pressure shifts network structure in a measurable way. Strong entries often use graph metrics, spatial comparisons, and careful uncertainty checks. The best projects ask which native plants lose the most important connections, not just which sites have more insects.

Project Variations

• Compare pollinator networks in park edges, roadside patches, and restored native habitat to see how land use changes invasive pressure.
• Focus on one invasive plant species and test whether its flowers attract a different pollinator mix than nearby natives.
• Use photo-based flower cover estimates instead of direct abundance counts, then test how image-derived cover affects network risk.

Learn More

• USGS Invasive Species Program: Find background on invasive-species impacts and management by searching the USGS site.
• NOAA Pollinator Resources: Read about pollinators, habitat change, and ecosystem links on NOAA pages.
• USDA PLANTS Database: Check native and invasive plant ranges and species records for your region.
• iNaturalist Help Center: Learn how to make high-quality observations and exports for analysis on the iNaturalist site.
• R Project and CRAN Documentation: Find free guides for network analysis and graph plotting by searching CRAN for bipartite and igraph packages.
• Ecology and Journal of Applied Ecology: Search these journals for review articles on plant-pollinator networks and invasive species.