Portland State University Students Assess Biodiversity in Mt. Richmond Forest

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Hyla Woods offers an immersive experience in a biodiverse forest setting within a 45-minute drive from the Portland State University (PSU) campus. This area was the original homeland of the Confederated Tribes of Grand Ronde, Atfalati, Kalapuya and Confederated Tribes of Siletz Indians. These woods offer an example of a sustainably managed and ecologically complex forest. This forest is being studied and rehabilitated, reinvigorated as a result of the Hayes family’s desire to more harmoniously connect with the earth and her rewilding process. A process in which we can build on and practice the notion of a reciprocal relationship with the land and in the process, understand our interconnections and symbiotic relationship to natural resources and the well being of our lives.

The Hayes use the Tracking Forest Health monitoring program in order to observe and document changes in their properties. Hyla is managed with biodiversity in mind to help strengthen forestry practices. With over 1000 acres of land, only 20% is logged and 80% is dedicated to supporting biodiversity. This space has allowed students at PSU within the Environmental Science department an incredible opportunity to visit the forest and learn methods of invertebrate pollinator sampling, plant identification and auditory bird identification.

Our study was specifically focused on monitoring for the presence of pollinators located near Mt. Richmond, on the east flank of the coastal range of the Northern Willamette Valley. This location includes different stages of forest growth including aspects of resiliency, change, and hope for the future as we learn about the biodiversity outcomes of sustainable forest management practices. Our study took place from August 8-11 2022, with average temperatures ranging from the mid 70’s to high 80’s (F) each day. While we found an abundance of flora and fauna species within this forest, there was also diversity among vegetation and insect species both between and within our three transects. The transects had some unique species that were only detected at a given sampling location despite being relatively close to one another and within moderate changes in elevation.

Approximate locations of our three Transects in the Mt Richmond forest

We set up three distinct transects, labeled Transect 1 (T1), Transect 2 (T2), and Transect 3 (T3), within three different locations in the forest. At each transect we collected data on invertebrates, birds, mammals, light density and vegetative diversity.

Light Measurement

To measure the light intensity of each site we used a light meter that measured the lux at each transect. Lux is the density of light in a spot. 1 lux= 1 lumen squared. Measuring light gives us clues as to why certain vegetation grows in that location and can serve as a proxy for canopy cover.

ß Light meter and datasheet

Bird Point Counts –

Bird Point Counts – At each of these locations we did bird point counts. Bird point counts are done by listening to the songs and calls of birds (and a few Douglas squirrels!) to identify species. In four 2.5 minute time slots we recorded how many times we heard each bird for a total of 10 minutes.

Mammal Monitoring

Trail cameras were set up at transect 1 and 3 to monitor any birds and mammals that passed through while we were away from the site. Unfortunately, there were some technical errors and the camera at transect 2 stopped working. We were able to capture deer, ruffed grouse, coyote, Douglas and California ground squirrels, chipmunk, and rabbit on the working cameras.

ß Two fawns seen on our trail camera in Transect 3

Invertebrate Trapping

Invertebrate traps were used to collect different pollinator species. These traps were composed of blue, yellow and white colored bowls to attract different pollinators. We then filled those bowls with a solution of water and soap to ¼ full to trap the insects to be able to view them the next day. The traps were left for 24 hours, and trapped specimens were collected in plastic containers and categorized in the lab.

ß Students collecting invertebrates from the pan traps

ß Invertebrate pollinator pan trap samples

ß Students sorting and pinning invertebrate samples in the lab

Vegetation Observations

At each transect, we took note of each tree, shrub, and herbaceous plant species within line of sight of our transect location. We identified unknown species with the use of Plants of the Pacific Northwest Coast by Pojar and Mackinnon, and relied on personal knowledge of native plants.

Transect 1 Findings

A more open and sunny area of the forest, containing much younger stands of big leaf maples, doug firs, and willow.

  • Highest relative elevation of the three spots, with an average lux level of 54,532 due in part to a history of heavy logging practices decades ago.
  • This transect contained the most species of herbaceous plants with 11 of them unique to the other two, and a higher relative number of invasive plant species.
  • Bee and wasp species were most abundant here, likely due to the abundance of light and herbaceous plants available to them.
  • This transect had the least amount of bird species that we were able to auditorily identify, which might have been due to a later observation time and a higher temperature of 75℉.

Transect 2 Findings

Located near a small shaded pond and running streams. This site was composed mostly of deciduous tree species of mature Alder, Maple, and a few Doug Firs.

  • This spot had the highest number of distinct pollinator species, but the lowest diversity of shrub and herbaceous vegetation species.
  • There were no vegetative species unique to this spot.
  • The largest number of individual wasps were found here, and this location had the second highest amount of individual flies and insects in the “other” category.

Transect 3 Findings

This site contained a mature forest of Cedars, Cottonwood, Doug Firs, Alders and Ash. This canopy created a highly shaded area and contained the largest vegetative diversity. Interspersed were nurse logs hosting smaller cedars and shrubs growing from them.

  • Had the lowest average light level at 5573 lux.
  • 6 different tree species were identified including 3 unique to this transect location, specifically, cedars, cottonwoods, ash, vine maples, ninebark and mahonia.
  • Invertebrate pollinator species were lower, containing only flies as well as 12 other non-pollinator species.
  • The birds were fairly active at this site, with approximately 8 species identified auditorily.
  • We observed many elk tracks on the logging road directly perpendicular to our transect.
 Transect 1Transect 2Transect 3
Warbler spyyy
Red-breasted Nuthatch yy
Dark-headed Junco yy
American Goldfinch  y
Bushtit (?)  y
Downy Woodpecker (?)  y
Douglas squirrely y
Water drop sound (?)  y
Mourning Dove y 
Stellers Jay y 
Spotted Towhee y 
Red-tailed Hawkyy 
Finch sp (?) y 
Total388

All three transects show incredibly different populations of invertebrates which correlate to the different light levels as well as shrub and herbaceous plant availability. T1 and T2 displayed the highest species diversity of invertebrates. This correlates with both sites containing the most open light swaths of forest and more herbaceous abundance. Interestingly, the T1 site also had the most invasive herbaceous plant species. T1 was the only transect to contain bees, wasps and flies, while T2 contained the highest diversity of invertebrates, but contained no bees. For the most mature stand of forest, T3, only flies and other non-pollinator species were recorded.

Our data indicates how sustainable, varied forest management practices can result in diverse vegetation, invertebrate, and bird species populations even within a small geographic area. Despite the close proximity of these sites, we observed unique ecological characteristics and species compositions at each individual transect. Hyla Woods serves as an example of how a sustainably managed forest can enhance biodiversity and provide educational opportunities in support of adaptive management practices.

Special thanks to Peter and Pam Hayes for letting us spend time at their property and learn more about monitoring biodiversity in these incredibly beautiful and ecologically rich woods!

This post was authored by the Portland State University summer 2022 ESM 342 Field Methods in Biodiversity course students: Leslie Campbell, Rowen Irene, Ashley King, Lauren Madzier, Ian Taylor, and Estefania Zavala, with support from their professor Leslie Bliss-Ketchum.