In response to a request for information about the flooding

by Patrick Donnelly

The following letter was sent to Birgitta Jansen in response to her request for information about the August rain events of 2023. – editor

Hi Birgitta,

Thanks for reaching out. The amazing thing about the Amargosa is that the species are actually adapted to floods. It’s a normal part of their life history. There is a species of speckled dace, alternately called the Nevada speckled dace or the Ash Meadows speckled dace (Rhinichthys osculus nevadensis) which lives in Oasis Valley, Ash Meadows, and the Amargosa Canyon.


Named springs and locations along the Amargosa River

Credit: Center for Biological Diversity

c. Map

Genetic work found that the Amargosa Canyon population was an admixture of Oasis Valley and Ash Meadows genetics. Which means that, during some mega flood events, speckled dace washed down from Oasis Valley; and separately, washed down from Ash Meadows. And then they interbred and the result is the Amargosa Canyon speckled dace. Isn’t that incredible? Speckled dace, surfing the waves of a thousand year flood all the way down the Amargosa River. And yet, we can believe it. The time back in 2015 when we paddled in a raft from Shoshone to Tecopa, the river was ¼ mile wide and 5 foot deep and flowing from Beatty to Badwater. So it can happen. (2015 incidentally was a roughly 40% larger flood event, at least by the river gage readings)

The other species I will mention is the Amargosa vole. Voles live most of their lives in a relatively small area, but data have shown voles to surf the waves of a flood, moving 1km or more at times of moving water.

It turns out that some desert creatures are very well adapted to millennia of flash flooding, and it may actually be an important vector for gene flow and dispersal.

We can see all sorts of other benefits from these floods. Ambrosia dumosa (AMDU), for instance, is a tiny little burrobush. I don’t know about you, but I took AMDU for granted in the years before the drought, just the aquamarine little bush that grows between the creosotes. But then the drought came, and the AMDU mostly died. Or looked that way. The desert became a sea of ghostly gray dead AMDU with sickly looking creosote between barely hanging on.

Now of course things started turning a corner for the desert last summer, when we got some rain. And last winter was of course the breaking of the drought, and the creosote have been looking much better for the past year. But the AMDU had yet to really recover from the drought.  And yet, two wonderful things happened after the rains from Hurricane Hillary. One, some of the AMDU began growing back, in some cases showing very very rapid growth. They would grow up from the middle, from the root stock, of what otherwise appeared to be a dead bush. And number two, miracle of miracles, we had what could only be described as a mass germination event. AMDU seedlings everywhere! And they also exhibited extremely rapid growth. Look at this little fellow. Grew from a seedling to having 6” long branches in less than a month.

Ambrosia dumosa

Photo: Patrick Donnelly

c. Pic 1 - Ambrosia dumosa

Another plant I observed that benefited from the rains was Oxystilis lutea, the "spiny caper". They are growing very robust and tall – this one was almost 6’!

Oxystilis lutea, the spiny caper

Photo: Patrick Donnelly

c. Pic 2 - Oxystilis lutea, the spiny caper

I have seen quite a lot of plantago coming up – this is tortoise food, so I’d be surprised if they weren’t out and about feasting on the unexpected abundance.

My good friend the Death Valley sage (Salvia funerea) has responded quite well to the rains as well. They exhibit some degree of drought deciduousness, but have regrown a bunch of late summer leaves after the hurricane. I even saw one flowering.

Death Valley sage (Salvia funerea).

Photo: Patrick Donnelly

c. Pic 3 - Death Valley sage (Salvia funerea)

These annuals are using this burst of moisture to get in as much photosynthesis as they can while they have the moisture to do it, to help replenish their reserves after being sent to the absolute brink of destruction by the drought. It just filled my heart with so much hope and joy to walk around the desert the past few weeks and see the utter resilience of this place responding so rapidly after being so severely impacted during the years of acute drought.

And of course the pollinators are out. I got this lovely photo of a swallowtail. Amazing what cell phones can do these days.


Photo: Patrick Donnelly

c. Pic 4 - Swallowtail

Hope you’re well Birgitta. Thanks for your work for our desert!


Patrick Donnelly

Great Basin Director

Center for Biological Diversity