After Two Weeks of Observing the SCU Lightning Complex, What Was Discovered?

Butterfly Mariposa Lily

With over 2,500 recorded observations stretching across the 620-square-mile SCU Lightning Complex fire footprint, Save Mount Diablo’s 2021 BioBlitz concluded with exhilarating findings.

By Denise Castro

Save Mount Diablo conducts annual BioBlitz events, usually a lightning-fast 24-hour biological survey in a specific area. From 2014 to 2016, we focused on the 3,000-acre Morgan Fire footprint on Mount Diablo.

Because of COVID-19, this year we opted for a safer approach and reformatted the event into a two-week, dispersed version that covered the nearly 400,000-acre SCU (Santa Clara Unit) Lightning Complex fire footprint. Check out our BioBlitz debrief for more on our amazing findings this year:


From April 17th to May 1st, participants were directed to burned areas in six different public parks and two public roads crossing through the fire footprint. Save Mount Diablo’s annual BioBlitz events will continue to focus on the SCU Lightning Complex fire footprint for the next two years.

How Information Collected During BioBlitz Is Useful

Triteleia laxa (Ithuriel's Spear)

Ithuriel’s spear (Triteleia laxa)

The BioBlitz events work as an important resource for data generation.

Cataloging the species found in certain locations will update past records and provide an ecological snapshot, which is especially important in this time of climate change.

Our investigation will provide insight into species that may need continued monitoring or direct management in the future. It may even identify new species.

Exploring the Diablo Range

We had amazing attendance this year thanks to our partnership with the California Native Plant Society as part of their long-term Fire Followers Campaign.

This partnership aimed to monitor the impact of the fire footprint on biodiversity and promote the exploration of the Diablo Range, an area that remains largely unknown.

BioBlitz Overview

Within the two-week period, more than 100 observers collected over 2,500 observations from across the northern Diablo Range, many of which were uploaded onto iNaturalist and eBird.

Many endemic species were found, including rare fire followers such as fire poppies, whispering bells, and golden eardrops. Participants also came across a variety of animals, like stone flies in the Del Puerto Creek, mountain lions in Henry W. Coe State Park, as well as a roadrunner, and nesting golden eagles on the Connolly Ranch.

The SCU fire had a myriad of intensities and effects. The low precipitation year is slowing regeneration, but experts’ overall assessment is that the fires functioned much like a controlled burn with positive ecological effects.

In some areas, especially on the west side of the burn area, grasslands have largely recovered. In other locations, 10, 30, or 50 percent of slopes have vegetation.

Woodland burned in varying levels of intensity. Chaparral habitats were a mosaic of burned and unburned areas.

Because rains were light, erosion was also limited, leaving soils less disturbed and encouraging regeneration (however slow).

Big wildflower displays could last longer than the average three to five years before chaparral plant communities grow thick again. However, multiple years of drought are having a big impact on water sources.

What Is the SCU Lightning Complex?

tufted poppy (Eschscholzia caespitosa)

tufted poppy (Eschscholzia caespitosa)

The SCU Lightning Complex began in mid-August of 2020 and lasted into early October of 2020.

This series of almost 20 fires lasted 44 days, scorching nearly 400,000 acres of land across five different counties in the northern Diablo Range. It’s currently the third-largest wildfire in California modern history.

The fire footprint extends from east of Mount Diablo at Morgan Territory and Round Valley Regional Preserves and the Los Vaqueros watershed (which is known as the Deer Zone part of the SCU fires).

It extends as far south as Henry W. Coe State Park and Pacheco Pass.

We’ve already begun examining the effects of the SCU fires in “Diablo Range Revealed,” a series of posts, videos, and photo galleries by Joan Hamilton. You can follow the series in Save Mount Diablo’s e-news, or on our website.

BioBlitz participants were encouraged to upload their observations onto the SCU Lightning Complex iNaturalist project. Save Mount Diablo held a special iNaturalist training/BioBlitz info session through Zoom on April 14 to provide more detail about burn sites and answer any questions on how to use iNaturalist. There were many exciting observations made throughout the two weeks.

Golden eagles

A group of Save Mount Diablo staff and local researchers visited the burn site on the privately owned 9,000-acre Connolly Ranch. There they saw four pairs of golden eagles, at least one with a complete nest, among many other species.

It is estimated that about 80 pairs of golden eagles overlap with the burn area, and researchers are very interested in learning more about how these pairs will respond to the wildfires.

Aquatic insects

Dr. Matthew Cover, Professor of Ecology at CSU Stanislaus, visited Del Puerto Canyon during the two-week event, and came across a Pacific clubtail dragonfly, which is somewhat rare around the area. Dr. Cover has been visiting the riparian streams in Del Puerto Canyon for years to sample for aquatic insects.

These perennial streams have high conservation value, because water sources are rare in the arid Inner Coast Ranges and support many species that have limited distribution throughout the Diablo Range.

He noted that the fire had come right up to the edge of the riparian habitat and burned some of the smaller cottonwoods, but left the large trees intact. His overall observation was that, surprisingly, the fire led to very few changes in water quality, or species richness and community composition of stream aquatic invertebrates.

Roadrunner and mountain lions

Many amazing observations were uploaded onto iNaturalist, including the sighting of a roadrunner and several mountain lions in Henry W. Coe State Park.

Snakes and lizards

There was a wide variety snakes and lizards seen across the fire footprint, including California king snakes, northern Pacific rattlesnakes, and Blainville’s horned lizard (a very charismatic reptile with a declining population due to habitat destruction).


Save Mount Diablo staff also had the opportunity to visit different burned sites across the northern Diablo Range, including Blue Oak Ranch Reserve near Mount Hamilton, Highway 130 from Mount Hamilton through Del Puerto Canyon, the Deer Zone east of Mount Diablo, and Henry W. Coe State Park. Every location had its own unique array of wildflowers and wildlife.

Staff began their drive onto Highway 130 from San Jose. The burn site came up almost immediately past the Joseph D. Grant County Park. From there on, there was a mosaic of hundreds of thousands of blooms adorning the burnt hills for miles.

There were all kinds of colors splashed across the burn, thousands of lupines, thick spots of tufted poppy (Eschscholzia caespitosa), Lindley’s blazing star (Mentzelia lindleyi), larkspurs (Delphinium sp.), innocence (Collinsia sp.), clarkias, among many more. There were also cobweb thistles (Cirsium occidentale) with gorgeous, vivid, hot pink flowers growing along the road.

Fire poppy (Papaver californicum)

fire poppy (Papaver californicum)

Much of the chaparral burned hot in the region, but staff observed the chamise and toyon beginning to grow back from basal burls.

Patches of the chaparral habitats were also covered in whispering bells (Emmenanthe penduliflora), Santa Clara thornmint (Acanthomintha lanceolata), and mariposa lilies (Calochortus venustus).

Fire doesn’t bring only destruction, it removes the dense understory; reduces competition; replenishes nutrients in the soil; and encourages new, stronger, and healthier growth.

Staff also visited the Deer Zone fire footprint during the first week of the BioBlitz and noted larger numbers of Mount Diablo fairy lanterns (Calochortus pulchellus) than any of us had ever seen anywhere in any year.

Fire poppies

During this visit, Save Mount Diablo’s Land Team made a rare discovery.

Fire poppies (Papaver californicum) are a rare California endemic that requires smoke from a fire to germinate and are, therefore, only seen after fires. 

This fire poppy observation is the first-ever record in the Morgan Territory/Round Valley Regional Preserve/Los Vaqueros area, and it’s also the first and only observation so far this year of the species within the entire 396,000-acre 2020 SCU Lightning Complex.

Save Mount Diablo’s 2021 BioBlitz ended with over 2,500 observations from about 100 observers. Experts, naturalists, and the public gathered over Zoom a few days after the event ended on May 6th for a BioBlitz debrief session to share their BioBlitz adventures and most exciting finds.

BioBlitz Debrief

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Photos from BioBlitz

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