Press "Enter" to skip to content

Fremont's Vernal Pools Return With the Wet Winter

As Spring makes way for Summer, the vestiges of an abundantly wet winter show in the shrinking pools of water — known as vernal pools — in the fields behind Fremont’s Auto Row. The pools are nature’s version of a pop-up, filling-up when the skies drop their rain —  drying up when the rain is gone. 

This year’s returning pools were encouraging for biologists after three years of drought, when the pools didn’t form at all, leaving the eggs of the pools’ seasonal critters languishing in the dry soil. 

“Because there’s no pooling, no water, no precipitation,” said Aiding Kakouros, a biologist with U.S. Fish and Wildlife, “we didn’t have full pools.” 

But Kakouros, who has studied these pools in the Warm Springs area of the Don Edwards Wildlife Refuge for years, this year’s winter of frequent atmospheric rivers and storms brought these seasonal wetlands roaring back. 

“This year the vernal pools are filled to the brim,” said Kakouros, who along with her team was wading in the water, taking count of the critters that call them home. 

The area’s vernal pools may form and evaporate, but they are the returning home of federally threatened California tiger salamanders and vernal pool tadpole shrimp. In the dry season, the critters return to the dirt to wait-out the return of rain. Once the pools are filled, the critters reproduce. 

A net gathers up dozens of California tiger salamanders from a vernal pool in Fremont’s Don Edwards Wildlife Refuge. 

For a decade, U.S. Fish and Wildlife has used teams of biologists to count the salamanders and shrimp to monitor their abundance. On a recent day, Kakouros and her team dragged a net across the pools of water, gathering up any creatures dwelling in them. One pull of the net yielded dozens of salamanders in various stages of development, preparaing for their exodus out of the dying pools. 

“Their presence in the abandons,” Kakouros said, “show us what is the health of our eco-system here.” 

The creatures that live in the pools suffered a rough time during the three years of drought. Kakouros said following two extremely dry years, the pools began to fill last winter — but then dried before their inhabitants could reproduce. 

Which is why those who return to the pools each year were encouraged to see them filled, with water remaining deep into the spring. 

“The special thing about this area is,” said volunteer Robin Agarwal, “give it a good rain and all these creatures that have been under the mud, that have been hiding since the dry season are able to come back and thrive.” 

Kakouros said this year’s counting has revealed healthy numbers of shrimp and salamanders which proves their ability to rebound following dire conditions. She predicts the abnormal swings between dry and wet will become the normal going forward.

“Because of the climate change we see huge swings, extremes,” Kakouros said, “three years in a row extreme drought and then this year with so much water.” 

Once the pools dry in the coming weeks, they will fill with wildflowers. Kakourous will shed her wading boots but will continue to return throughout the year to monitor the area’s changing conditions. Until then, she’s happily taking-in the water-filled wetlands and their aquatic life. 

“I’m especially joyful,” she said, “and amazed to have the pools filled.” 

Source: NBC Bay Area

Be First to Comment

    Leave a Reply

    Your email address will not be published. Required fields are marked *

    %d bloggers like this: