About Us

The Sierra Nevada Network (SIEN) is one of 32 National Park Service inventory and monitoring networks across the country that monitor the condition of park ecosystems. SIEN works with four parks: Sequoia and Kings Canyon, Yosemite, and Devils Postpile. Interested in seasonal field positions? Visit our Work with Us page.

SIEN is responsible to a board of directors and technical committee composed of park superintendents and staff. Program guidance and oversight is also provided by the National Park Service's Inventory and Monitoring Division. The network leverages staff and resources by collaborating with parks, other networks, and partners.

Need to get in touch? Here's how to contact us.

Network Staff

Woman stands in front of a scenic lake with rugged mountains in the background.

Rachel Wolstenholme, Acting Program Manager

Rachel Wolstenholme has worked as a Biologist for the NPS and non-profit organizations for over 25 years. Her focus has been on endangered species recovery and includes work in Yellowstone, Glacier, Pinnacles and Channel Islands National Parks. Since 2020 she has been serving as our regional wildlife biologist. Rachel's first role with NPS was leading a dynamic team at Pinnacles National Park focused on California Condor recovery. Her projects have ranged from gray wolf monitoring to island fox recovery, as well as wolverine and spotted owl surveys. She conducted water quality and quantity monitoring for several years in Wyoming's Wind River Range. Rachel’s M.S. degree from the University of Montana focused on human-wolf interactions in a rural ranching community. Along with her focus on finding common ground and endangered species recovery, she believes in strong collaboration with universities and partnering with NGOs. In her free time you’ll find Rachel enjoying the trails of our parks.

Woman sitting on granite outcrop, looking back at camera. Views of large granite domes in background.
Sarah Wakamiya

Sarah Wakamiya, Data Manager

Sarah joined the Sierra Nevada Network in August 2021. In her role, she designs and manages applications and workflows for storing, analyzing, and sharing network data. She has been a Data Manager with the I&M program for over a decade, previously working at the Mid-Atlantic Network, Northern Great Plains Network, and most recently the San Francisco Bay Area Network. She has a B.S. in Neurobiology and Physiology from the University of Maryland – College Park and a M.S. in Wildlife Ecology from Southern Illinois University – Carbondale. Her research as a graduate student focused on landscape-linked population dynamics for peregrine falcons and swamp rabbits. These days she is particularly drawn to the interaction of data and art through data visualization and loves learning about the different biological systems the I&M program monitors. When she’s not solving data puzzles, she enjoys trail running, rock climbing, art (drawing, watercolor, and photography), and trying not to injure herself while learning to ski.

Woman wearing hat and warm jacket stands wearing a pack with a view of rocky slopes and Wind River Mountains in background.
Erika Blomdahl

Erika Blomdahl, Ecologist

Erika Blomdahl started as the new Sierra Nevada Network Ecologist in early July 2022. The ecologist manages our high elevation forest and wetlands monitoring projects.

Erika is pursuing her PhD in Ecology from Utah State University. Her dissertation explores disturbance regimes, their climatic drivers, and disturbance interactions across montane and subalpine forests of western North America. She is also a Fellow in the Climate Adaptation Science program at USU and is involved in research on the social dimension of fire in California.

Previously, Erika coordinated the development of the Utah Fire Atlas, a state-funded project to improve monitoring of trends in wildland fire across the state. She has also managed a forest dynamics lab, and has spent many seasons in the field and camping throughout the West. Her master’s work, at Utah State University, explored fire refugia and endangered species habitat in the southern Sierra. She has a B.S. in Conservation & Resource Studies with a Forestry minor from U.C. Berkeley. When she is not learning about forests, Erika thoroughly enjoys trail running, backcountry skiing, yoga, reading, and gardening.

Woman wearing warm hat and coat stands near a view of the redrock cliffs in Grand Canyon National Park
Virginia Javier

Virginia Javier

Virginia Javier is the new Logistics Coordinator for the Sierra Nevada Network for the field season between May and October. She helps with field logistics for our monitoring projects. She graduated in May 2024, receiving a B.S. degree in Natural Resources with an emphasis in Rangeland Management from the University of Arizona. While in undergrad, Virginia was a Weed Warriors VIP, as well as and an Scientists-in-Parks intern at Cabrillo National Monument, which inspired her to work in public service after graduation. Outside of work, she enjoys cooking, baking, hiking, and going to concerts/music festivals.

Seasonal Staff - And the Paths They Travel from Here

In the late spring, summer, and early fall our office building becomes more lively and busy than usual, when our seasonal staff arrive to conduct some of the most critical work of long-term monitoring - the field data collection! Without them and the data they collect, we would not have a long-term monitoring program. The seasonal staff who are drawn to our program love to spend their time in the extensive wilderness of our large parks, they become experts at packing backpacks efficiently, cooking with campstoves, navigating to remote sampling sites, and collecting excellent quality data. Some love it so much they come back for multiple seasons, and our program benefits from the long-term knowledge they bring to monitoring projects. They also appreciate the beauty of where they work, and getting to explore large chunks of the stunning wilderness of these parks.

In the following series of articles, some of our former seasonal staff share their forays into graduate school, and in some cases how their work here helped motivate and inspire them to continue their education, and explore in more depth the environmental sciences they were able to participate in here, and have the opportunity to do projects of their own.
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    Last updated: May 31, 2024