Last updated: December 17, 2020
Article
It's a Wrap: Completing the Crater Lake Vegetation Map
Fall/Winter 2018 - Dodging fires at Crater Lake National Park in the summer of 2017, the Klamath Network vegetation mapping crew gathered their last season of field data. The summer’s plots check the accuracy of the final map, setting the stage for publication.
NPS
Dominic DiPaolo, the current project lead, has been involved since data collection began in 2011, along with Dennis Odion, one of the original planners in 2008. The final map meets important accuracy thresholds, and DiPaolo is excited about what it can contribute to park management:
“The vegetation map is more like a digital atlas than simply a static map of park vegetation types. It can be a geographic reference for planning, and can also house geographic data for just about anything you’d want to locate in the park.”
Why map?
Vegetation maps were one of 12 inventories representing the first component of the National Park Service’s “Inventory and Monitoring Program.” These surveys catalogued current resources or conditions in parks, like air quality, species lists, and soil maps—basic information that was often lacking. Park managers need to know what natural resources exists in their parks and where to find them to do their jobs effectively. The new Crater Lake National Park vegetation map offers more detail and higher accuracy than the coarser scale LANDFIRE vegetation data previously available to the park.
Steps in making a vegetation map
A vegetation map is a multiyear project that begins with an up-to-date set of baseline imagery. 2011 color aerial photography with 1-meter resolution (1 pixel per square meter) was used as the basis upon which to draw the vegetation map.
Step 1—Find out what’s there!
Crews sampled plots in the field that captured the full variety of park vegetation. They identified all plant species in a plot, using the dominant and most commonly associated species to generate an initial list of distinct plant associations for the park. This initial list was then matched as closely as possible to existing plant associations in the US National Vegetation Classification (USNVC). (Interestingly, 37 of the 80 final Crater Lake plant associations have not been described yet in the existing USNVC.)
Step 2—Define the map units
Based on what was visually distinguishable in the imagery, they grouped plant associations together—following the USNVC hierarchy—to create a list of the foundational map units.
Step 3—Start mapping
This is the part where lines were drawn, creating polygons no smaller than 0.5 hectares. Inevitably, the mappers made some adjustments as they grappled with the range of variability they encountered for each map unit in the park.
Step 4—Check the map’s accuracy
You might call this the ground-truthing stage. Staff sampled up to 30 randomly selected points in each map unit category to find out how well conditions on the ground matched the assigned map unit characteristics.
NPS
Challenges
Wildfires were a huge challenge for the mappers during their final summer. The Spruce Lake and Blanket Creek Fires prevented field crews from sampling some of the original accuracy assessment plots. This kept DiPaolo and Odion on their toes, establishing new plots on the fly (though carefully following protocol) to make sure they had enough in each map unit category. It was no small accomplishment! While the map will no longer represent severely burned areas, DiPaolo sees a bright side. Crater Lake has experienced several fires over the past decade, resulting in a range of newly regenerating areas that are currently described in detail by the new vegetation map. These existing postfire vegetation types exhibiting different stages of vegetation succession can be used to help understand conditions as the vegetation redevelops following the 2017 fires as well.
All vegetation maps have a range of accuracy across vegetation types. One of the toughest categories to map accurately was “cliff, scree, and rock,” which often contained more vegetation than was visible from the imagery. In contrast, several vegetation types were mapped with 100% accuracy, including ponderosa pine woodland, white fir forest, lodgepole pine forest, montane grassland, and wet meadow and marsh.
Uses of a vegetation map
Vegetation maps are valuable as snapshots in time to help us learn how landscapes change and respond to disturbance over time. They identify unique or sensitive habitats that we might not have known much about. For example, the new vegetation map delineates a community of special interest to the park—subalpine fell fields. These high elevation, windswept habitats support a unique herbaceous plant community, including some rare and endemic species. The map also identifies stands of whitebark pine, a declining keystone species of high elevation ecosystems that is currently a candidate for listing under the Endangered Species Act.
Vegetation maps can tell us where to look for sensitive wildlife by pinpointing the plants they rely on for food, shelter, and nesting habitat. Along those lines, the park’s terrestrial ecologist, Sean Mohren, plans to upgrade his spotted owl habitat map with the new, more detailed vegetation data. Mohren conducts compliance surveys for projects near known spotted owl territories. He also collects acoustic data on the distributions of spotted owls and their competitors, barred owls. Knowing more accurately where to survey and where to place his acoustic detectors will boost Mohren’s efficiency.
NPS / Leela Hickman
Unexpected bonus
One advantage of having “eyes on the ground” as part of any fieldwork is incidental discoveries. The mapping crew stumbled upon a great grig in Shasta red fir forest, which you can read about in our latest Featured Creature.
It’s a wrap!
Crater Lake National Park’s new vegetation map is ready for use! We published the final map and associated GIS products in June of 2018. In July, project lead Dominic DiPaolo and coauthor Dennis Odion rolled out the map to park resource managers and other interested folks at Crater Lake, explaining how to use the map and database and answering questions.
End products
The following map products are available from the NPS Integrated Resource Management Applications portal (IRMA):
- The full report, containing:
- A detailed, color vegetation map (also available separately in letter and poster sizes)
- An accuracy assessment to show managers which vegetation types are most and least accurately mapped
- A dichotomous vegetation key for placing a site into the plant associations described
- A description of each plant association, with photos
- An ArcGIS geodatabase with all the plot locations and detailed vegetation polygons
Article by Sonya Daw, Klamath Inventory and Monitoring Network
Adapted from The Klamath Kaleidoscope newsletter, Fall-Winter 2018 issue, by Jessica Weinberg McClosky