Slime mold networks

As I passed through a eucalyptus grove on campus, something brilliant yellow caught my eye. I bent closer. A gloopy, ruffled smear of yellow covered a curl of eucalyptus bark. Tendrils crept out from one end. A slime mold? I took a picture and uploaded it to iNaturalist when I got home.

iNaturalist is a website or app in which you can upload photographs of living things, tag their location, and add your guess of an identification. The site's artificial intelligence suggests possible species to help you with your identifications. Once you put up a picture, other people can confirm your i.d. or suggest an alternative. The site suggested dog vomit slime mold-- Fuligo septica-- for my picture. I don't know much about slime molds but that sounded like a good description of what I'd seen!

The next day, Sarah Lloyd, a slime mold expert from Tasmania, Australia had left a comment on my post: "It's the plasmodial stage of a slime mould that's still transforming. Can you return and get a photo of mature fruiting bodies?I don't think it's Fuligo. It's more likely to be Leocarpus fragilis; the substrate looks right and the species seems to be extremely common at the moment in California." I went back to the same spot two days later, and there was nothing yellow to be seen. I started poking around, and found tiny brick-red bulbs coating the eucalyptus bark on the ground.

It was indeed Leocarpus fragilis! This slime mold, like others in its class, spends much of its life as a tiny single-celled organism. But after rain, it is able to find much more of the bacteria and fungi it eats, and the cell begins to expand dramatically. That blob of yellow slime I saw was one single enormous cell! The cell send out thin tendrils searching for nutrients. A slime mold in this phase grows into a web or network, passing nutrients through its pathways, growing thicker where conditions are good. Researchers have found that slime molds can solve mazes and generate efficient solutions to problems of how to connect a set of dispersed resources. Slime mold networks can take a range of forms.

Eventually, the slime mold transforms again, forming fruiting bodies where spores grow. These spores are eventually dispersed and start the life cycle anew as individual slime molds.

There's an interesting parallel I think, between the lives of slime molds and our new human way of living with the internet. Slime molds build networks and webs, finding and passing nutrients. We form virtual networks and webs, finding and passing knowledge, lies, jokes, art, crap, and memes. This web connected my photo of a yellow smear to a naturalist in Australia who knew what it was, and sent me back to see a miraculous transformation.

iNaturalist

Sara Lloyd's website

Article about Sara Lloyd from iNaturalist NEW!

Intro to slime molds from the University of California Museum of Paleontology at Berkeley

Slime mold intelligence from Nature

Newts on the move

We're under the oaks. Drips from last night's rain are filtering down from the canopy, soaking into the leaf litter. The forest floor is a mosaic of browns, oranges, and greens—oak leaves, bay leaves, acorns, lichen-covered sticks, patches of mud. We're looking for a particular orange—the creamy light-orange of chanterelles. They are late to come up this year. The series of weak storm systems we've had makes the forest floor look wet enough, but it seems we haven't had quite the necessary soaking yet. Something catches my eye, a darker, rusty orange. And it's moving. A rough-skinned newt deliberately lifts one front leg, and the back leg on the opposite side. It negotiates over a stick. I see a flash of bright orange as its belly shows. I hunker down. I watch the newt slowly make its way downhill.

Each winter, rough-skinned newts (and their close relatives, California newts) migrate to ponds and pools to reproduce. Scientists aren't exactly sure how the newts navigate, but it seems they use a combination of smells, sights, and following slopes downhill.  A newt can travel about half a mile in five days. Walking to my mushroom spot, I cross a small muddy stream that only appears in the winter. Perhaps the newt I saw was headed to a pool in this stream.

The newt's bright orange belly is a signal to possible predators of the powerful toxin in the newt. A single rough-skinned newt has enough toxin to kill several adult humans. This trait developed through co-evolution with the garter snake, the rough-skinned newt's only predator. As rough skinned newts evolved ever stronger levels of toxin, garter snakes developed ever greater capacity to withstand the toxin.

A somewhat more distant relative, also found in our area is the California slender salamander. I find these by looking under rotting logs. You might at first mistake this salamander for a worm. Then you notice the bug-eyed old man face, and the limbs, thin as angel hair pasta. These salamanders also have a seasonal rhythm. In the dry months they burrow under ground and become dormant. With enough rain they emerge, searching for insects in underground tunnels, below rotting logs, and in the leaf litter. While the rough skinned and California newts undertake epic (for their size and speed) journeys, a California slender salamander stays put. Most individuals never leave an area of about two meters.

Ensatina is another local species that lives its life in a small area. These can also be found under rotting logs.

Newts and salamanders highlight for me the different scales of our shared world. It takes a newt days to clamber down to its breeding pool—the longest walk of its life. I walk the distance in minutes. My home in the flats is like a distant galaxy for the newt. The newt experiences details of the forest floor that I pass right over: the contours that lead rainwater to filter down to a muddy pool, the routes over or under a fallen log. And what details and intricacies a slender salamander must know of its two-meter world!

(We did eventually find the first few chanterelles of the season!)

More information about newts and salamanders from Amphibiaweb:

• Rough-skinned newt
• California newt
• California slender salamander
• Ensatina

Places to see newts and salamanders:

• UC Berkeley Botanical Garden (The pond in the Japanese garden is a great place to see mating newts)
• Tilden Park (They close South Park Road for the season to keep migrating newts safe!)

A swirl of wild geese

First you hear them: a rippling, overlapping chatter. Then you see that the field is covered in geese: dark gray geese in front, a sea of white birds behind. A wave of wings lifts up from the mass and blurs the sky above. The wave spreads as more birds take off. The white geese reveal striking black on their wings.

There are so many of them. It baffles the eyes. It sends a startle of delight to your chest.

Every winter, thousands of snow geese, Ross's geese, cackling geese, and white fronted geese migrate south from their nesting grounds in Canada and Alaska. Huge flocks spend the winter in the Central Valley, including at the San Joaquin River National Wildlife Reserve where my parents and I saw them from the Beckwith viewing platform just before New Year.

The dark gray geese we saw were cackling geese. Cackling geese look almost exactly like Canada geese but smaller, and until recently the various populations were considered subspecies of Canada goose. Those we saw were Aleutian cackling geese, the subspecies of cackling goose that nests in the Aleutian Islands, the arc of volcanic islands trailing off to the southwest of mainland Alaska. They travelled over 2,000 miles from their nesting grounds to this muddy field near the San Joaquin River.  Through binoculars, I spotted a few bright orange goose feet. These belonged to greater white-fronted geese, just a few of them tucked in among the masses of cackling geese. The white geese behind were snow geese and Ross's geese, two species that are nearly identical: almost all white when on the ground, with just a touch of black near the rear, bold black on the wings in flight. The snow goose has a larger bill than the Ross's and some have a slight yellow tinge on the head and neck.

Our understanding of species has changed based on genetic evidence, and continues to change as scientists gather and analyze more of this data. Genetic evidence revealed that cackling geese are not just smaller Canada geese, but rather their own species. Cackling geese look so similar to Canada geese (and Ross's geese look so similar to snow geese) because their evolution into separate species is relatively recent. There is still some interbreeding among the species and subspecies where they overlap. Changes in land use, hunting, conservation and climate over the last several centuries has altered the ranges of these goose species and likely affected the ongoing subtle evolution of the shifting populations.

Watching the flocks of geese fly through the chill December air, the groupings  form, shift, and reform. Threats or disturbances I can't see send swaths of bird into the air. Something sends them slanting toward the river, while another group settles to the ground. The complex patterns mirror the changes and shifts in their populations on a much larger time scale.

Cornell Lab of Ornithology:
Cackling goose
Canada goose
Snow goose
Ross's goose
Greater white-fronted goose

San Joaquin River National Wildlife Refuge