|Red-bellied newts spend most of their lives underground and we know little about what they do there.|
They were all the same. We were stunned.
Discovery of a New, Disjunct Population of a Narrowly Distributed Salamander (Taricha rivularis) in California Presents Conservation Challenges. I have no expertise in genetics and won't go into the details of their analysis - these can be found in the published paper. A quick summary is that two mitochondrial genes and one nuclear exon were sequenced. The authors state:
Taricha rivularis lacks geographically structured mitochondrial lineages and exhibits extremely low levels of overall genetic diversity. The nuclear marker POMC is invariable, and less than 0.2% divergence in mtDNA is found across the approximate 200 km geographic range of the species, remarkably low for salamanders in this region, and for salamanders in general . . . Other salamander species with similar coastal distributions exhibit substantially greater levels of mtDNA variation or geographic structuringThese results were unexpected because most salamander species show quite a bit of genetic diversity. Sometimes this is obvious to the human eye, such as the differently colored Ensatina subspecies 'ringing' the Central Valley of California. Other times, it takes genetic studies to show how some salamander populations have slowly developed unique quirks in their genetic code often as a result of geographic barriers or behaviors that isolate them into subpopulations.
Salmon are an example of a philopatric species that returns to breed in the same stream in which they were born. As a result, distinct salmon runs occur on separate river systems representing unique genetic material in the same species. If generations of salamanders likewise return to the same stream to breed, over time, one would expect the animals of each stream system to become less genetically similar to subpopulations of the same species in a different stream.
A recent study of California giant salamander in the Santa Cruz Mountains shows this pattern. Briana Callahan (2010), a graduate student at Sonoma State University, found that California giant salamanders north of San Francisco Bay (in Marin, Sonoma and Mendocino Counties) are genetically divergent from populations in the Santa Cruz Mountains, probably as a result of the formation of an inland sea millions of years ago which isolated these distant populations from each other. Furthermore, she also found variation among the populations in the Santa Cruz Mountains often from one watershed to the next, indicating a finer scale of differentiation. Despite being the largest terrestrial salamander in the world, the California giants have a relatively low dispersal rate and an average home range of less than an acre. This may isolate subpopulations into separate breeding streams and therefore create genetic diversity among streams.
|Returning to breed in the very same streams in which they were born - philopatry|
Why were the red-bellied newts so similar to each other? An earlier study (Kuchta and Tan, 2006) found low levels of genetic variation in red-bellied newts in contrast to the other three Taricha species and suggested that either the red-bellied newts had recently expanded from a common point or their ability to travel relatively long distances for a salamander might allow continued exchange of genetic material.
Some of the Berkeley team's genetic results also indicate a geologically recent and rapid "population expansion [of red-bellied newts] following a bottleneck". It is unclear why they responded differently than the other Taricha and other salamander species of the central coast which over geologic time spread and contracted their ranges, became isolated in the peninsula of the Santa Cruz Mountains, and subsequently developed some degree of genetic diversity.
|Just how far can this handsome newt travel - over generations?|
Wild speculation and geologic dreaming? So inspires the dark-eyed stranger.
Even though recent human introduction of this population seems more likely, salamanders don't easily take to such long distant relocations. Of the few known successful introductions, two were a result of fishermen moving salamanders as bait, and one was accidentally introduced in a shipment of oak trees with bark (Bonett, 2007). Red-bellied newts do not make good bait due to the neurotoxin in their skin, and the poisonous effect of such "water-dogs" is generally well known by rural California residents and sportsmen.
|Warning belly: bright red warns predators of potent neurotoxin in this newt. |
Not likely to be used as fish bait.
|Some of the beautiful and biologically rich park land protected in|
Monte Bello Open Space Preserve and Upper Stevens Creek Park
|A ten-thousand newt day - California newts breeding in pond on Monte Bello Open Space Preserve|
|Although we never saw their eggs, we often found small rough-skinned newts like this one indicating that they were likewise successfully breeding|
|Random Truth was one of several nature bloggers who helped us search for red-bellied newts on rugged terrain. He shares his take on the adventure with fabulous rbn photos and humor at Nature of a Man.|
|Chuck has an uncanny ability to find reptiles and amphibians.|
|"That one is redder," she said of my faded and splattered photo.|
"Honey," she replied, "when I was a girl wandering these hills, I had a pony and a gun, nothing fancy like a camera." But she gestured in a general direction where she most often saw the "really red ones" and that was the same direction as the small creek on my map.
|Monte Bello Open Space Preserve protects a diverse range of habitats for all kinds of newts|
We entered the forest and made our way downhill where we eventually found a small creek with a rushing flow no more than a foot or two deep and a few feet wide. The banks were winding and sharply cut with a wild tangle of downed trees and exposed roots. This was not going to be a gentle stroll besides a pastoral stream. The only way we could inspect that creek was to walk in it, and climb over, under or around ferns, branches, and trunks, hop over big rocks and sink into pools. We stepped into the cool water. I went upstream while Chuck searched downstream. We were seeing California newts lurking in the dark edges of the creek or sunning in open water. We had to closely examine these first newts just to make sure we weren't missing the red-bellieds, and soon our sleeves were soaked.
|A small creek with lots of life and trip hazards|
|Red-bellied newt at creek edge - still has rough and bumpy skin|
|Most of the newts in the creek that day were males.|
We handle newts briefly for identification purposes and then replace them at the same location and rinse our hands
|Checking out the creek|
|Arboreal salamander at Newtlandia|
I would like to have talked to Dr. Twitty about the discovery of red-bellied newts in the Stevens Creek watershed. I can't quite get my head around the fact that he would have been 108 years old when Chuck first reported the bright red newts on his running path. Even though Twitty has left us many scientific publications and a delightful reflection on his career in Of Scientists and Salamanders, I still would like to have shared the thrill of this discovery so close to his Stanford home and hear his interpretation of where the tumbling newts had come from and where they were going.
I would especially like to have told him about the small unnamed creek Chuck and I explored, spring-fed so that it was still flowing in a third year of drought, about our day of bouncing from creek bank to creek bank to get around big boulders, bowing under or climbing over log jams and constantly splashing and tripping in the cool, fast-moving current. I would report to him the size and sex and show him the photos of everyone of those 39 newts, how I wrote everything down in my field notebook and somehow managed to not drop my camera in the water. Well, almost everyone of those newts.
This is the part of the day I would most like to have shared with Dr. Twitty because even though he may have never said so in his papers, I know that he too was just as much in love with a world that could create such a marvelous creature. As I was twisting my body between fallen branches on the creek that day, I saw the chocolate brown head of a red-bellied newt pop up from an eroded scarp on the opposite bank. The newt set both of its fore limbs on the top of a curled alder root and turned its head to follow the downstream flow of the creek below. I reached across the small creek to pick up the newt with the intention of measuring it, but my feet were stuck between some roots and I couldn't quite stretch my arm that far without falling over. The newt shifted and looked up at me with its solemn dark eyes, slowly turned and with a flash of its bright red palms disappeared into the black passage behind the root.
|Crawling in and out of holes in the ground, tree trunks and roots, |
red-bellied newts spend lots of time hidden underground
Even though 40 years have separated our stream-tromping, in many ways, Dr. Twitty and I have shared our adventures with this dark-eyed stranger. On rainy days I'm still out there with my gang, looking for red-bellied newts, searching for their eggs by sticking our hands in dark shadows under cool, flowing water, and recording it all in my field notebook. Except these days, if you look in my field notebook, you will find that we have christened that unnamed tributary. We call it Twitty Creek.
|Exploring Twitty Creek|
There are very few moments we have like that in our lives - a unique adventure, a new discovery,
something beautiful and improbable that exists on its own and has nothing to do with us.
We are just observers. - First Ever Red-Bellied Newt
This post is the last in a series on the discovery of red-bellied newts in the Santa Cruz Mountains of California. To start at the beginning of the series go to Mystery of the Red-Bellied Newt.
American bullfrog, Lithobates catesbeianus
Sierran treefrog, Pseudacris sierra
California red-legged frog, Rana draytonii
San Francisco gartersnake, Thamnophis sirtalis tetrataenia
Arboreal salamander, Aneides lugubris
Yellow-eyed ensatina, Ensatina eschscholtzii xanthoptica
California slender salamander, Batrachoseps attenuatus
California giant salamander, Dicamptodon ensatus
Rough-skinned newt, Taricha granulosa
California newt, Taricha torosa
Red-bellied newt, Taricha rivularis
Bonett, Ronald M., Kenneth H. Kozak, David R. Vieites, Alison Bare, Jessica A. Wooten, and Stanley E. Trauth, September 2007, The Importance of Comparitive Phylogeography in Diagnosing Introduced Species: A Lesson from the Seal Salamander (Desmognathus monticola), BMC Ecology, 7:7.
Callahan, Briana, 2010, Impacts of Landscape Features on the Genetic Structure of the California Giant Salamander (Dicamptodon ensatus), Sonoma State University.
Howard, Arthur D., Geologic History of Middle California, University of California Press, 1979.
Kuchta, Shawn R. and An-Ming Tan, 2006, Limited Genetic Variation Across the Range of the Red-Bellied Newt, Taricha rivularis, Journal of Herpetology, Vol. 40, No. 4, pp. 561-565.
Reilly, Shawn B., Daniel M. Portik, Michelle S. Koo and David B.Wake, September 2014, Discovery of a New, Disjunct Population of a Narrowly Distributed Salamander (Taricha rivularis) in California Presents Conservation Challenges, Journal of Herpetology, Vol.48, No. 3, pp. 371-379.
Twitty, Victor Chandler, 1966, Stanford University, Of Scientists and Salamanders, W.H. Freeman and Co., San Francisco.