Yews are popular landscaping shrubs but they don’t last long in the face of deer overpopulation.
All yew species are toxic to some degree, but our native Taxus canadensis is less toxic than others and was used medicinally. Deer don’t read the warning labels. They love yew.
Every night they creep up behind Carnegie Museum and browse the yews along the driveway to the parking garage. They nip off the small branches and eat all the leaves. The shrubs struggle to grow new leaves for photosynthesis before the deer return.
Yew overbrowsed by deer behind Carnegie Museum, 16 August 2022 (photo by Kate St. John)
Deer have killed the yews closest to the sidewalk (dead twigs), overbrowsed the middle shrubs (green knobs), and cannot yet reach the tallest branches. But they are eating their way there.
Yews browsed by deer behind Carnegie Museum, 16 Aug 2022 (photo by Kate St. John)
Don’t assume their love stops with yew. There are more delectables in Schenley Park that they adore. Soon we’ll explore more.
Have you ever seen the Devils Tower in northeastern Wyoming?
I had no idea it existed until Allison Cusick displayed a photo and jokingly described it as the world’s largest petrified tree during his presentation on Botanical Superlatives. I’ve never been there but I was hooked.
The origins of this gigantic “tree stump” are as amazing as its appearance.
Though no one knows for sure, most geologists agree that it’s a magma intrusion — not a volcano — of rare igneous rock called phonolite porphyry that formed 50 million years ago. At first it was buried underground but erosion has exposed it to stand 1,267 feet above the Belle Fourche River.
The Devils Tower is important to Native American culture and was established as the first National Monument in 1906 by President Theodore Roosevelt. It is one of the few monuments that allows rock climbing.
The ice on Antarctica is a dynamic system that gains 2000 cubic kilometers of ice per year from precipitation and loses it to melting and icebergs. Unfortunately the continent is losing more ice than it gains. This month two new studies from NASA JPL revealed that the ice is disappearing twice as fast as previously estimated.
Researchers found that the edge of the Antarctic ice sheet has been shedding icebergs faster than the ice can be replaced, doubling previous estimates of ice loss from Antarctic’s floating ice shelves. Ice loss from calving has weakened the ice shelves and allowed Antarctic glaciers to flow more rapidly to the ocean, accelerating the rate of global sea level rise. …
In fact, the findings suggest that greater losses can be expected: Antarctica’s largest ice shelves all appear to be headed for major calving events in the next 10 to 20 years.
The 200-foot-tall (60-meter-tall) front of the Getz Ice Shelf in Antarctica is scored with cracks where icebergs are likely to break off (photo from NASA/GSFC/OIB)
In the interior of the continent ice loss is much harder to see as melt water seeps through the ice into lakes and streams beneath, then to the sea. The only clue to this melt is that the glaciers lose altitude.
To measure this ice loss NASA analyzed data gathered by satellites passing over Antarctica from 1985 to 2020. The illustration below shows a pass made by the ICESat-1 satellite whose mission ended in 2010.
NASA’s map of the elevation changes shows that a few places gained elevation (blue) but more of them lost. The worst melting was in the red zones.
(map from NASA JPL, arrow added by Kate St. John)
Why does this matter?
As the glaciers melt on Antarctica and Greenland their water raises sea level around the world, but the rise is not equal everywhere. Uneven gravitational forces cause tiny elevation changes in sea level, called sea level fingerprints, that peak in the tropics and have the deepest valleys near melting glaciers. Those few cities near melting glaciers will see a drop in sea level while those farthest away from glaciers will have the highest rise.
For instance Reykjavik, Iceland, which has melting glaciers of its own and is close to Greenland, will see a net loss of sea level (below).
Meanwhile New York City and London will see a big sea level rise because of Antarctica + Greenland. (For more information see Which Glaciers Will Flood Your City.)
3 Large Milkweed bugs + 1 Small Milkweed bug (photos by Kate St. John and John English)
14 August 2022
At this time of year you’ll often see black and orange bugs crawling on milkweed seed pods. These are milkweed bugs, large and small, that consume the seeds by injecting saliva through the pod shell into the seed beneath and sucking out dissolved seed matter. Though the “large” and “small” bugs look very similar they are not the same species.
Large milkweed bug, Sept 2021 (photo by Kate St. John)
Large milkweed bugs are orange and black with a black horizontal band across the middle of the back. In this species you can tell male from female. On the underside of the bug, the 4th abdominal segment is a black stripe on males and two black spots separated by orange on the females. Click here for a photo of two mating: female at top, male at bottom.
Small milkweed bug, August 2022 (photo by John English)
The orange and black “small” milkweed bug (Lygaeus kalmii) has a different pattern on its back: a black heart in the center and two black patches on either side (see top right photo).
Juveniles are dependent on milkweed but when milkweed is scarce the adults become scavengers and predators that, according to bugguide.net, have been reported feeding on honey bees, monarch caterpillars and pupae, and dogbane beetles.
L. kalmiirange across the US and Canada except for the southeastern US. They overwinter as adults by producing antifreeze in their bodies to survive the cold.
False milkweed bug, March 2022 (photo by Kate St. John)
Like the monarch butterfly, the orange and black color of milkweed bugs warns predators that they are toxic. Viceroy butterflies mimic monarchs so they won’t be eaten. “False” milkweed bugs (Lygaeus turcicus) mimic small milkweed bugs (L. kalmii) for the same reason.
The black pattern on the “false” milkweed bug is slightly different. Instead of a black heart it is a V that seems to overlay the black beneath it much like the W overlays the V in West Virginia University’s logo.
Closeup #1 of fossil in Schenley Park (photo by Kate St. John)
10 August 2022
Sometime this summer the Department of Public Works placed a large sandstone rock at the base of the stairs behind the Schenley Park Visitors’ Center. The prominent fossil facing the stairs tells a story about life in Pittsburgh 300 to 330 million years ago.
Fossil rock at the base of the WPA stairs, Schenley Park, 6 August 2022 (photo by Kate St. John)
The sand became sandstone and in the early 21st century the rock separated from its fellows thereby exposing the fossil. This rock many have fallen at the Bridle Trail rockslide.
Locations of two closeup photos of the fossil in Schenley Park (photo by Kate St. John)Closeup #2 of fossil in Schenley Park (photo by Kate St. John)
I have never seen Lepidodendron’s closest living relative, Lycopodium, in Schenley Park …
Lycopodium (ground pine or club moss), Laurel Ridge State park, 30 May 2022 (photo by Kate St. John)
… but I’ll look for it now that I’ve seen its fossil ancestor.
Thank you to Public Works for placing this fossil rock on display in Schenley Park.
p.s. If this Lepidodendron had fallen in a swamp instead of on a sandy beach, it would have become coal. Read about similar fossils at Ferncliff Peninsula in Ohiopyle State Park in this vintage article: Fossils at Ferncliff
(photos by Kate St. John, illustrations from Wikimedia Commons; click on the captions to see the originals)
Red aphids coat false sunflowers in Schenley Park, 6 August 2022 (photo by Kate St. John)
9 August 2022
Every August the false sunflowers in Schenley Park become covered in red aphids. My first reaction is disgust, then I look for aphid predators and protectors.
Aphid predators include ladybugs, syrphid flies (hover flies), parasitic wasps and lacewing larvae. Their protectors are the ants who harvest their honeydew.
The ants were out in full force and chased off a ladybug that flew to escape them.
Ants harvesting aphid honeydew, Schenley Park, 6 August 2022 (photo by Kate St. John)
The ladybug found a safer place to munch on aphids. No ants in sight.
Ladybug predator of aphids, Schenley Park, 6 August 2022 (photo by Kate St. John)
Syrphid flies hovered and darted among the leaves, choosing to lay eggs where there would be plenty of aphids for their larvae to feed on.
Syrphid fly on a leaf near the aphids, Schenley Park, 6 August 2022 (photo by Kate St. John)
Larger predators lay in wait to eat the aphid eaters. Can you see the spider inside this flower?
False sunflower with aphid on outer petal, spider lurking inside flower, 3 August 2022 (photo by Kate St. John)
Here’s a hint. His feet are dangling are at the bottom of the circle.
Spider lurking inside the flower (photo by Kate St. John, retouched)
I’m sure there were many more predators lying in wait for aphids. This video shows what to look for.
Birds move around on their own but some of our most common species came from a different continent or a different habitat and were introduced here by humans. Now you can see both native and exotic ranges in eBird after they made changes this month to the species maps.
House sparrows and pigeons, both introduced from Europe, are a case in point. In the eBird maps below native range is purple, exotic range is orange.
We tend to think that all exotic species were introduced from Eurasia to the Americas. Canada geese made the reverse journey. Europeans actually wanted them. Are they regretting that decision?
Captured house finches were illegally transported from California to New York City in the 1940s to be sold as “Hollywood finches” in the pet trade. Just before the law caught up to them, the vendors released the birds on Long Island. The “exotic” house finch population has now spread across the continent. eBird shows it on the map below. Click here and scroll down to see how they spread through the decades.
The northern bobwhite does not do well in urban and suburban habitats but as a game bird it is raised in captivity and released for hunting in gamelands, agricultural fields and open woods. Have you seen a bobwhite in your backyard? It is an escapee within its “exotic” range.
