Return to Warm Springs Seasonal Wetland


In mid-April 2011, Ivette Loredo of the Warm Springs Seasonal Wetland hosted a hike out to the vernal pools, a closed part of the Don Edwards National Wildlife Refuge. Claudia and I welcomed the chance to revisit this landscape and found it interestingly different from the previous year. The flowers were more subdued this year (Downingia were few and far between) but then again it is earlier in the season and we had heavy late-spring rains.

Warm Springs Seasonal Wetland - April 2011

A 360-degree panorama (best viewed large).

A panorama of our small party. In the center you can see a small group of Bos primigenius that came over to observe our small group of Homo sapiens while we observed Lasthenia conjugens. This is a panorama stitched from 14 portrait format images taken from the top of a 35-foot pole.

This grassland landscape has low hummocks and swales that define shallow pools during the wet winters of California. As the seasons progress the pools dry out and stay dry through our rainless summer and early fall seasons. Living in the extreme wet/dry cycles of the vernal pools requires a fair bit of genetic ingenuity and Warm Springs is home to rare species of flora and fauna – each adapted to the circumstance of the landscape. Examples are the California tiger salamander, Ambystoma californiense, which spends the majority of the year aestivating (a sort of hibernation) underground and the tadpole shrimp.

Warm Springs Seasonal Wetland - April 2011

Contra Costa Goldfields

The images in this set show a broad expanse of grassland punctuated by small pools (now largely dry). The periphery of these pools display several interesting and rare wildflowers. Most of the yellow ringing the small pools is Contra Costa goldfields (Lasthenia conjugens), a member of the Aster family. It is a colorful spring annual, golden yellow in color and about 3 to 4inches tall with light green finely divided leaves. A rare and endangered species, it is only found at the edge of vernal pools in a few California counties. Next to the Contra Costa Goldfields and toward the center of the vernal pools we saw mats of blue and white Downingia. They can apparently tolerate deeper water and thus have this interior position. The pools also had subtle light green tones of Woolly Marbles.

Warm Springs Seasonal Wetland - April 2011 Warm Springs Seasonal Wetland - April 2011

Exclosures (my new word for the day.)

The photographs also show a series of rectilinear exclosures that are part of a study on the benefits of moderate grazing on the protected landscape. There are more photos from the hike in this Flickr set:

I am taking these documentary photographs under a Special Use Permit from the US Fish & Wildlife. Kite flying is prohibited over the Warm Springs Seasonal Wetland without a Special Use Permit as is access to this part of the Don Edwards National Wildlife Refuge.

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