From UC Davis
Rare desert plants that are more sensitive to solar development
- by Kat Kerlin
- May 03, 2021
Throughout the history of the West, human actions have often plagued the desert – and their actions have failed. In the 1920s, the Colorado River Compact notoriously distributed the water that is still used by several western states today, as water measurements were taken during a humid period.
Currently, the operators of the massive Ivanpah solar power generation system in the Mojave Desert are spending around $ 45 million on desert tortoise abatement after undercounting the initial number of endangered animals prior to construction.
A study published in the journal Ecological Applications from the University of California, Davis and UC Santa Cruz warns of another possible mismatch between desert timing in the race against climate change and the rapid development of renewable energies.
“Our study suggests that in California’s Mojave Desert, which supports nearly 500 rare plant species as well as a rapidly growing solar industry, green energy and conservation goals may conflict,” said lead author Karen Tanner, who heads the work as a PhD student carried out .D. Student at UC Santa Cruz on a scholarship led by Rebecca R. Hernandez, Assistant Professor at UC Davis.
Tanner spent seven years studying the demographics of two native desert flowers – the rare Barstow woolly sunflower (E. mohavense) and the common Wallace woolly daisy (E. wallacei) – and comparing their performance both outdoors and under experimental solar panels . The authors wondered how desert-adapted plants would react to panels that block light and rain. Would rare species respond to these changes differently than common species?
These are not easy questions. At one point, Tanner taped tiny seeds onto individual toothpicks to collect emergence data. For another, she searched the desert floor on her hands and knees to count the emerging seedlings of the rare sunflower – about the size of a miniature picture at maturity.
The rare woolly sunflower from Barstow. (Karen Tanner)
Ordinary Wallace’s woolly daisy. (Karen Tanner)
Super bloom surprises
Such careful engagement is one of the reasons no previous studies have modeled species responses to photovoltaics at the population level. It takes time and tricky logistical and mathematical challenges to model little-known species interactions in the evading desert. What is nowhere in sight one year can flourish the next.
This element of surprise is what makes “super blooms” so special and fascinating. These wildflower explosions cover desert landscapes after particularly humid years and are considered critical to the long-term persistence of annual desert populations.
Wildflowers blanket the desert near the UC Davis study area in the Mojave Desert. (Karen Tanner)
The study found that the effects of solar panels on the response of plants were heavily influenced by the weather and the physical features of the landscape. During the 2017 super bloom, the panel shadow had a negative impact on the population growth of the rare species, but had little impact on the common relative.
The study suggests that rare species are more sensitive to effects on solar evolution than common species. It highlights the potential for solar panel effects, which can vary between species, as well as spatially and temporally.
A question of time
The study provides an example of the importance of taking the time necessary to understand an ecosystem before it is irreversibly changed.
“The desert – and many other biomes – do not respond to our time scales,” said Hernandez, co-director of the Wild Energy Initiative through the UC Davis John Muir Institute. “If we want to understand them, we have to examine them against the time scales they operate. Otherwise, it’s like taking a picture of a moving train and calling it a shipping container. It makes sense to build renewable energies in places that have already been stripped of their biology. Let’s not wait until the existing roofs are supplied with solar energy. But in natural settings we have to listen and observe first. “
Research funding was provided by the California Energy Commission.
HT / EurekAlert!