Category: Natural Sciences

Ellanor C. Lawrence Park botany and ichthyology

new to meCharles Smith led the botany basics workshop at Ellanor C. Lawrence Park for Fairfax Master Naturalists. (I studied the eastern section of this park for a class in 2014.) We met a lot of old friends from the plant world. Charles pointed out a non-native invasive that I had not seen before, Small Carpetgrass (apt name, that) (Arthraxon hispidus).

In the meadow, Charles pointed out Beaked Panicgrass (Panicum anceps). I need to look at this plant a few more times before I can grok it. A tip for learning sumacs: fruits hang down from Winged Sumac.

"what good looks like"On the west side of Walney Road, we did a very short ascent of the Ridge Trail to a patch of woods that has been left alone by White-tailed Deer. Charles describes this view a “what a good forest looks like.”

the worksIn the afternoon, Chris Ruck and his team electrofished a short reach of Big Rocky Run. Again, this was not a complete, protocol-compliant survey, but rather some cherry-picking so that we could see what species could be found in the stream. Forgive me for geeking out on the equipment, but it’s pretty cool.

working downstreamnet 'imA circuit is established between the anode, the pole in Danielle’s right hand, and the cathode, the cable in her right hand. Fish in the water are stunned, and can be scooped up in a net for study, as Chris is doing in the image at right. Voltage and other electrical characteristics can be adjusted for water conditions. You want rubberized waders for this job; if you’re wearing breathable waders, you will probably feel an unpleasant tingle, or worse.

waiting to be keyed outSome of the catch, ready for identification.

pretty darterlook on the sunny sideWe turned up 13 of a possible 20 species or so, according to Chris’s accounts. We spent a lot of time with the keys and the minnow representatives (family Cyprinidae). A little easier to ID were these Fantail Darters (Etheostoma flabellare) at left, and these four sunfish species (at right).

The scoop

The photograph of the Munsell soil color chart book pulled me up short. As I read Richard Schiffman’s piece, my thoughts bounced around from “wow, this is cool that soil scientists are getting profiled in the Times” to “New York has a soil brokerage clearinghouse so that good fill dirt from a construction site can be used to rebuild a wetland? That’s bananas—no, that’s brilliant!”

While the idea might seem obvious, Dr. [Dan] Walsh maintains that this is the first soil exchange anywhere in the world that is run by a city government. It is currently being watched by officials from New Orleans and Los Angeles as well as municipalities in Germany, China and Australia, which are considering implementing similar programs.

* * *

“We’re essentially matchmakers,” Dr. Walsh said. “We don’t stockpile the soil, so both a donor and a recipient have to be ready at the same time. Our job is to coordinate the transfer.”

The NYC Urban Soils Institute has plans to establish a soil museum in Brooklyn’s Green-Wood Cemetery—something for my to-see list in New York.

Some links: 83

Some links, Wild Card Edition:

  • Andrea Appleton’s report: Chris Swan uses vacant lots in Baltimore (there are 14,000 at present) as experimental ecology plots.
  • Callan Bentley road tests a tool for teaching his geology students what went on in the mid-Atlantic: a worksheet matrix that brings together the What (e.g. Culpeper Basin), the When (e.g., Taconian orogeny), and the Why (evidence, to be filled in by the student).
  • Like Ducks? Thank a Hunter, by Wes Siler.

    There are 47 million birdwatchers in the U.S., but only 2.6 million waterfowl hunters. Conservation of wetlands falls disproportionately on the shoulders of hunters. And that’s a problem because hunter participation is decreasing. With fewer hunters, who’s going to pay for wildlife conservation?

Some links: 82

Some links, Creepy Parasite Edition:

  • Dodder (Cuscuta sp.), a twining plant parasite, can inject bits of microRNA into its hosts, blocking gene-based plant defense mechanisms. Summary of new research by Saima Shahid et al. at Phys.org.
  • We’re understanding more about how the fungus Ophiocordyceps unilateralis takes over the behavior, if not the mind, of its ant hosts, as Ed Yong reports.

    Once an infection is underway, he says, the neurons in the ant’s body—the ones that give its brain control over its muscles—start to die. [David] Hughes [at Penn State] suspects that the fungus takes over. It effectively cuts the ant’s limbs off from its brain and inserts itself in place, releasing chemicals that force the muscles there to contract. If this is right, then the ant ends its life as a prisoner in its own body. Its brain is still in the driver’s seat, but the fungus has the wheel.

A mystery: 8: solved

Alonso Abugattas identifies the mystery spiders that I met two autumns ago: Neoscona sp., probably N. crucifera. He explains why they “seem to appear” in fall:

During the earlier part of the year you likely never noticed them. Not only were they much smaller as spiderlings, but they hide during the day. They would tear down and consume their webs every morning, so you often didn’t notice their webs they constructed nightly. They did this to avoid daytime predators such as birds or wasps from finding them. Mud Dauber wasps for example often sting and paralyze many of these when they’re young, stashing them in their mud nests as living paralyzed food for their own babies.

But by Fall, they’re often too big for wasps to eat. Many wasps have also concluded hunting and egg laying by this late in the year. So the spiders sometimes hang out during the day. Many birds also don’t go after them as much, having no babies to feed or they themselves leaving on migration South. Prey also gets scarcer as it gets colder, so leaving the web up during the warmer day increases the chance of a catch. Consequently, Spotted Orbweavers don’t hide as much and also don’t tear down their webs and rebuild them at night as much once autumn arrives.

Smart animals

Netting bats on the ashes of a Staten Island landfill, from Laura Bliss.

A lot of New Yorkers still think of Freshkills as a dump, [Danielle Fibikar] says, even though it’s coming back to life. The place is misunderstood, sort of like the bats.

“There’s a lot of stuff people don’t pay attention to in this city,” she says. “I think they’re scared of what they don’t know.”

Alas, the story is marred by a copy editing blunder:

In New York City, where nine species of bats are known to migrate during the summer, a single little brown bat is capable of devouring up to 100 percent of its body weight in insects, a diet that includes mosquitoes.

Devouring up to 100 per cent of its body weight… per day? per minute? per fortnight?

One of tens of thousands

Life achievement unlocked: today for the first time I marched in a major political protest on the streets of Washington, D.C. As a member of the March for Science, I walked from the Washington Monument grounds, within sight of the White House, down Constitution Avenue to 3rd Street, on the fringe of the Capitol grounds. Weather conditions at the rally were less than ideal (drizzle and showers), but I stuck to the principle that there is no such thing as bad weather, just inappropriate clothing.

getting ready to marchI walked with a group well-organized by Audubon Naturalist Society (that’s us mustering on the steps of the National Museum of Natural History). ANS’s march leaders had the brain wave of bringing decorative bird spinners as a rallying point. The spinners (and the stylin’ t-shirts) brought us lots of attention, especially from journalists major and minor.

Principle above sap

That’s how it was. It was like we had had something in Jefferson for eighteen years and whether it has been right or whether it had been wrong to begin with didn’t matter anymore now because it was ours, we had lived with it and now it didn’t even show a scar, like the nail driven into the tree years ago that violated and outraged and anguished that tree. Except that the tree hasn’t got much choice either: either to put principle above sap and refuse the outrage and next year’s sap both, or accept the outrage and the sap for the privilege of going on being a tree as long as it can, until in time the nail disappears. It dont go away; it just stops being so glaring in sight, barked over; there is a lump, a bump of course, but after a while the other trees forgive that and everything else accepts that tree and that bump too until one day the saw or the axe goes into it and hits that old nail.

—William Faulkner, The Town, chap. 19

Going beyond

Ed Yong has put together an excellent background piece about the outbreak of Proliferative Kidney Disease that has killed whitefish and threatens trout species. The fish kills led Montana Fish, Wildlife and Parks (FWP) to shut down of 183 miles of the Yellowstone River. The coverage elsewhere that I saw simply repeated the FWP statement that a “microscopic parasite” was responsible and left it at that. But Yong did the reading, and used it to describe the peculiar morphology and life cycle of the infectious parasite Tetracapsuloides bryosalmonae, a jellyfish relative and one of the myxozoans.

Myxozoans have performed a crazy evolutionary double-back:

In this free-swimming form, they look very jellyfish-like, with identifiable tentacles, mouths, and guts. Perhaps the ancestors of myxozoans went through a similar phase in their evolutionary history, when they were already devoted parasites, but still kept some obvious traces of their cnidarian heritage.

As they evolved further down the parasitic path, they lost these ancestral physical features. They did away with many genes too. “They have the smallest known animal genomes,” says [Paulyn] Cartwright [at the University of Kansas], “and they lack some of the genes that we consider hallmarks of animal development.” For example, the all-important Hox genes, which direct the construction of animal bodies… are simply missing in myxozoans.