Analysis: Lake vulnerability


Use a Lakes Vulnerability Model to learn more about the lake where you did your VS observations, and what factors make it more or less at risk of having invasive species.

Models like this one are particularly useful to scientists and resource managers who wish to mobilize public participation in identifying and possibly changing factors that invite vulnerability to new species introductions.

NOTE: Models are not perfect representations of what is actually happening. They are powerful tools, but you must use them carefully and understand what they can and can not tell us. This model uses just the top 9 risk factors (see Part 2).


Find your lake's score


1. Open the 2004 Lakes Vulnerability Analysis results spreadsheet in Excel or Numbers

2. Use “FIND” or "SEARCH" to find that lake where you looked for species

  • In column “U” is your lake's score
  • 40 indicates the lakes most at risk
  • The least vulnerable lakes in Maine have a score of 9

3. In general, is your lake’s score higher or lower than other lakes in Maine?

4. Based on what you saw when you did your VS fieldwork, do you think this score makes sense? Does it concern you? Make you smile?


Find out why your lake got the score that it did

1. Look along the top of the spreadsheet at each of the criteria the model uses:

  • How much use the lake gets
    1. Distance to major roadways (state & interstate highways)
    2. Human population within 30km
    3. Boat launch access
    4. Shoreline development
  • How close the lake is to infested waterbodies
    1. Distance to already infested lakes
    2. Connections to infested waterbodies
  • Potential for aquatic species to live there
    1. Amount of lake habitat
    2. Surface area of the lake

    NOTE: These are the criteria that this model uses to determine how relatively vulnerable each lake is to invasion. It is not an exhaustive list of what puts lakes at risk, but rather a list of the most important criteria according to what scientists know about how aquatic species move from place to place.
    Would you add anything else to this list?
    How do you think it might change the model?

2. Use VS and Google Earth map layers to better understand the criteria and check the model:

Distance to the interstate and state highways

    1. Go to the VS map
    2. Zoom in to your lake
    3. Find interstates I-95 and Route 1
    4. Find state routes
    5. Estimate the distance from road to lake using the distance scale at the bottom of the map
    6. Check the model results – do they make sense?

Distance to an infested lake and/or connected to an infested lake


    1. Click the "Change Search" button to open the Advanced Search. Use these search criteria:
      a. Keyword: freshwater
      b. Invasives
      c. Found
      d. ID confirmed

    2. Was there an invasive aquatic species found in your lake, nearby, or in a connected waterbody?
    3. Check out the model results – do they make sense compared to what you see on the map?

Boat launch access

    1. Launch the special 2011 VS/DEP invasive aquatic species Google Earth file
      You may need to install Google Earth!

    2. Launch the VS boat launch Google Earth file
    3. Zoom in to your lake
    4. Is there a boat launch on your lake?
    5. Check the model results – do they make sense compared to what you see on the map?

Human population within a 30km lake buffer

    1. Launch the VS Maine human population Google Earth file
    2. Match the color of your lake with the map legend. Is the population higher or lower than in other areas?
    3. Check out the aerial view of the lake to see how many houses and other buildings surround the lake. Do a lot of people live close to the lake?
    4. Check the model results – do they make sense compared to what you see on the map?


Make a prediction!

Now that you are familiar with the model and maps, try using them before you go out to do your next VS investigation. See if you can use them to predict whether or not you'll find invasive species.

1. Find a new lake to explore in the 2004 Lakes Vulnerability Analysis results spreadsheet

  • Do you want to look for species at a lake with a similar or different vulnerability score?
  • Do you want to look for species in a lake connected to yours?

2. Find the waterbody on the VS map

  • Check its distance to major roads
  • Check its distance or connection to an infested lake

3. Find the waterbody on the Google Earth map, and turn some layers on (should be saved!)

  • Check whether it has a boat launch
  • Check how many humans are in the area, and how developed the surrounding area is

4. Based on what you learn from the model and maps, make your prediction!

  • Do you think you'll find an invasive species?


I really liked it because I got to learn new things about this subject.