Carnival of Science!

The lead story on the BBC New's Science and Environment page is on the research of one of the post-doctoral researchers in my professor's lab. The idea is rather simple, the process was complex.
We know that climate changes over time, and that where one can find a particular type of habitat changes with the climate. Recently, using a wide range of data sources, scientists have been constructing both a detailed history of how climate has changed over time and what climate parameters limit the extent of particular habitats, such as South America's Atlantic Rainforest. My lab-mate, Ana Carnival (along with several collaborators) combined the climate history data with the climate requirement data to make maps of how the extent of the Atlantic forest has changed over the last 20,000 years. She found that there were a few relatively small areas that had been rainforest the whole time, even when climate shifts caused the rest of it to change to other habitat types, such as grassland. She identified these as 'rainforest refugia,' areas where rainforest species could survive through the millenia when the climate was inhospitable elsewhere. She then predicted that these refugia should be the centers from which genetic diversity spread to the rest of the forest once its borders once again grew. To test these predictions, she gathered genetic samples from three species of frogs which can survive only in the rainforest. Sure enough, the frog's DNA told the story she had predicted, confirming the refugia she had identified based on climate models. This is not only cool science, it has significant conservation implications. These refugia should house a large portion of the diversity found in the rainforest, because at some points in the last 20K years, all the rainforest species lived there. This suggests that if we are forced to make choices about which land to preserve (which we are) we might do well to preserve these refugia. And both the methods and the conclusions are potentially generalizable to other thretened habitats around the world.

One final thought: This is very cool work, and very much in line with what most people in my adviser's lab study, but it is so far from my own work that I barely understand the details. This may be why I don't notice any glaring errors in the BBC article, or maybe the UK press are not as bad at writing about science as the American press.

Picture of Science! Tiger Salamander Larvae

My wife and I were walking up to Cecret Lake, at 10,000 ft. in Little Cottonwood Canyon, above Salt Lake City. When we got there, I said, "Oh fish!" Iris pointed out that they had too many dangley bits, and I took a closer look. "Tadpoles!" I said, but then I remembered that tadpoles don't have external gills along the back of the head like that. So I eventually figured out they must be salamander larvae. But what salamader has 6 inch long larvae? The tiger salamander, Ambystoma tigrinum.
This struck us as particularly fortuitous, as we only a month ago named a kitten Tigrinum, in honor of this species. Quite a resemblance, wouldn't you say?


Tiger salamanders often breed in mountain lakes and streams, and their populations often die out when fish are introduced to their previously fishless breeding grounds. Those big slow larvae are easy prey for predatory fish.

Global Amphibian Declines call for frog costumes.

There are few, if any, taxa losing species diversity as quickly and thoroughly as the amphibians.

From amphibiaweb.org:

"Amphibians, a unique group of vertebrates containing over 6,200 known species, are threatened worldwide. A recent assessment of the entire group (globalamphibians.org) found that nearly one-third (32%) of the world’s amphibian species are threatened, representing 1,856 species. Amphibians have existed on earth for over 300 million years, yet in just the last two decades there have been an alarming number of extinctions, nearly 168 species are believed to have gone extinct and at least 2,469 (43%) more have populations that are declining. This indicates that the number of extinct and threatened species will probably continue to rise (Stuart et al. 2004)."

And this is almost surely an overly optimistic view. The thousands of species for which we have no data are not considered threatened, and an unknown number of others, likely in the hundreds, has gone extinct without ever being discovered.

Amphibian lineages that have existed for tens of millions of years are ending shockingly quickly. The factors that are killing off these ancient groups are all the works of humanity: pesticides, industrial pollutants, introduced species and diseases, habitat destruction and alteration and rapid climate change. There is no reasonable doubt but that we have driven the rate of amphibian extinction to several thousand times its natural rate. We could barely kill them off more quickly if we tried. Genocide is not too strong a term.

Amphibians are widely seen as indicator species. Healthy ecosystems have healthy amphibians. Indications are poor.

So to help raise (the currently abysmally low) awareness of the scope of amphibian declines, Iris and I have decided to walk Bay to Breakers wearing homemade from costumes. And we hope to organize a group of friends and colleagues to walk with us, similarly garbed. A costume recognizable as an amphibian, or even a shirt with amphibian pictures on it. Perhaps we will hand out informational pamphlets to people who ask what we are about. If you are interested in joining us, please email me.

Field Notes

FEB. 23 2008
D. Levitis
Hillside Natural Area (North Unit) El Cerrito, Contra Costa County, CA

Sijie Mao, Nichole Winters and I went out from 1300 to 1530. It was quite windy with very strong gusts, temp in the lower 50s and varying between slight drizzle and significant rain. Our fist stop was the detritus field around the storm drain at the lowest point in the park, just behind my house, under the Eucalyptus. A lot of good cover items, but nothing under there. From there we went just up the hill to the small pile of shipping pallets on the grass. Under the first one I lifted was an Aneides lugubris (Arboreal Salamander)! The first I'd seen here. We took this as a sign of good salamandering to come.

We followed a route approximated by that marked on this map, but with many side excursions to check under log, rocks and other cover objects:


Much of this part of the Nature Area has many of the cover objects removed for yearly mowing, so much of the available cover is in piles of cut log pieces or small rocks piled at the base of trees and in gullies.

Sijie and Nichole are extremely contentious about putting every cover item back exactly as it was, and are energetic and enthusiastic herpers. We found almost nothing under rocks, but the logs were very productive today. We checked under approximately 400 wood bits and 100 rocks/cement bits and found 71 Batrachoseps attenuatus (California Slender Salamanders) 3 Aneides and one Elgaria multicarinata (Southern Alligator Lizard).

The Aneides were all near oaks, as Dave Wake told me to expect, while the Batrachoseps were under logs and a few rocks in every habitat we checked. The Elgaria was under a pine log in grassy habitat.

In addition to the herps, invertebrates were extremely numerous under cover objects, including Jerusalem crickets, cave crickets, ants, termites, ground beetles, several kinds of spiders including a couple of Black Widows, copious pill-bugs, snails, slugs, worms and sundry.

Many fresh gopher diggings were evident in the soft wet earth, and many of the logs and rocks we lifted had smaller rodent tunnels, quite possibly vole. Deer prints and fox scat were in abundance.

One bird species to add to my list for the nature area, Wild Turkey. One was seen at the northwest corner of our route, just north of Snowdon Ave. and another was heard responding to its calls. Nichole took pictures of the turkey, which was tame enough to allow her to approach to within 6 meters.

Our explorations revealed no standing water in which frogs could breed, which may explain their absence from our observations.

Birding today wasn't great, due to wind and rain, but saw/heard following birds today:

Western Scrub-Jay (2)
American Crow (10)
Northern Raven (2)
Black Phoebe (1)
Yellow-rumped Warbler (25)
Chestnut-backed Chickadee (4)
House Sparrow (15)
Ruby-Crowned Kinglet (2)
American Robin (40)
California Towhee (3)
Dark-eyed Junco (4)
Wild Turkey (2)
Red-shouldered Hawk (1)
Anna's Hummingbird (3)
Mourning Dove (6)

Mammals:
Eastern Fox Squirrel (Sciurus niger) (2)
Mule Dear (Odocoileus hemionus) (tracks)
Voles (Microtus californicus? runways and burrows)
Pocket Gophers (burrows)
Fox (Grey fox? scat)

Herps:
Southern Alligator Lizard (Elgaria multicarinata) (1)
California Slender Salamander (Batrachoseps attenuatus) (71)
Arboreal Salamander (Aneides lugubris) (3)