Since plants are rooted to the ground, the only way they find a new place to live is through seed dispersal. Pressure to find new places is intensified by climate change but a study published this month in Science points out:
Half of all plant species rely on animals to scatter their seeds through hitchhiking in scat, fur, or beaks. When mammal and bird populations decline, so does the ability plants have to disperse their seeds and adapt to climate change. Loss of mammals and birds cuts a plant’s ability to adapt by 60 percent.
In 2017 study at Utrecht University found that mallards (Anas platyrhynchos) significantly help plants and isolated wetlands by dispersing seeds in winter.
Mallards change their diet during the year, from carnivorous in the breeding season to vegetarian in winter. During migration they stop to eat then disperse seeds later along the way. This particularly helps isolated wetlands that would not gain new seeds otherwise.
Mallards also help every day on their wintering grounds by moving back and forth from roosting to feeding areas. Where there is hunting pressure you might not see this because mallards change their ways: eating at night and hiding at the roost during the day.
This weekend we’re in Tidewater Virginia where the trees are bare but not empty. Many hold green balls of American mistletoe (Phoradendron leucarpum), a hemi-parasitic plant that extracts water and nutrients from tree branches while it also photosynthesizes.
At this time of year it sports sprays of white berries that are toxic to humans but good for birds.
While the birds eat the berries I marvel that mistletoe is common here. We don’t have it in western Pennsylvania (‘x’ = Pittsburgh).
At home we buy mistletoe in a store to carry on this Christmas tradition.
Though now a symbol of deserts everywhere, this unusual “tree” is native only to the Sonoran desert of Arizona, California and northwestern Mexico.
Saguaro (pronounced “sah-WAH-ro“) grows to 50 feet in height; its tremendous weight, up to nine tons, is supported by a skeleton of about two dozen spongy, wooden rods. Accordion pleats [expand and] contract as they gain and lose moisture. White flowers open after nightfall and close by late afternoon the following day. Saguaro has fleshy red fruit. Giant, leafless, columnar tree cactus with massive, spiny trunk and usually 2-10 stout, nearly erect, spiny branches.
Birds, animals and humans make use of this cactus.
Native Americans made use of the entire cactus. … Gila woodpeckers and gilded flickers make round holes near the tops of branches for nests that are used afterwards by elf owls, cactus wrens, and other birds. Wildlife, especially white-winged doves, consume quantities of the seeds.
Nature was busy this week. Spiders or insects wove tiny white cocoons inside this hornbeam seed structure. Chickadees look for these cocoons and eat the tasty treats inside.
As predicted, Schenley Park’s gingkos lost all their leaves in a single day — 20 November.
Norway maples were not far behind on the 24th.
I went to Schenley Park golf course to find a merlin just before sunset on 23 November. Instead I found three merlins jostling for the highest perch on the highest hill. The tallest snag in this photo is not the highest perch but the dot on top is merlin #2 of 3 who is watching the airshow as 2,500 crows fly over from the Allegheny Valley to where? Crows were still passing overhead when I left.
If you’ve ever tangled with Japanese barberry (Berberis thunbergii) you know this thorny plant has pretty berries but grows quickly into an impenetrable hedge. Imported for landscaping in the late 1800s, it has gone wild in the state and invaded the woods. Deer refuse to eat it. Despite its invasive attributes it was still sold for landscaping in Pennsylvania until now.
Last month the PA Department of Agriculture added Japanese barberry (Berberis thunbergii) to the state’s list of noxious weeds. As of 8 October 2021 it cannot be legally sold or cultivated in the state though you may see it in nurseries while enforcement is phased in over the next two years. In the meantime, you should not be offered Japanese barberry as a landscaping choice; don’t buy it.
By fall 2023 Japanese barberry should be a thing of the past in the landscaping world but it is rampant in the woods and already may be in your yard. Cultivars were bred for colorful leaves from yellow-green to red to purple.
In the wild and waste places it reverts to plain green leaves.
It is hypothesized that spread of barberry is correlated with the spread of Lyme disease. Tick numbers are higher in areas with thick barberry understories, as opposed to areas with controlled barberry or no barberry. In one study, 280 ± 51 adult black-legged ticks, Ixodes scapularis, were found per hectare in a barberry infected area, while only 30 ± 10 adult black-legged ticks were found per hectare in otherwise similar area with no barberry present.
On 4 November the leaves glowed yellow as the sun gained altitude at Frick. When the sun melted the frost, leaves quickly loosened and dropped from the trees.
On Saturday morning at Yellow Creek State Park the frost was beautiful, ephemeral and cold. Hoarfrost decorated the weeds in the parking lot.
Frost remained in a tree’s shadow but not for long.
Last week I re-learned how to dress for winter. This week will be warm with highs in the 60s, lows in the 40s, temperature inversions and bad air in Pittsburgh.
Roger Day captured these views of the Mon Valley yesterday morning, 7 November, from Frick Park’s Riverview overlook. The Allegheny County Health Department has issued an air pollution warning and the state DEP has issued a Code Orange warning. Read more here.
Most intriguing on my daily walks last week in Phoenix were the barrel-shaped yellow fruits atop fishhook barrel cactus (Ferocactus wislizeni). I missed the flowering (click here to see) but the fruits may persist for more than a year after the flowers fade into dried brown tufts on top of the fruits.
A closer look shows a few seeds remaining where each fruit broke off.
There were no fruits on the ground near this specimen at Reach 11 Recreation Area, probably because the park has so many javelinas. I saw the footprints of these peccaries (not pigs) but didn’t see any of the animals. Here’s what one looks like in a photo from Wikimedia Commons.
Javelinas and squirrels eat the lemony-flavored fruits and some websites say we can eat them too, but sparingly. The fruit is mucilaginous like okra. The cactus contains oxalic acid, a poison that causes nausea and diarrhea in low doses and death in high doses …
… which might explain the other evidence left behind by the javelinas. Were the javelinas sick to their stomachs?
“That meal was great,” said the javelinas, “but I feel a little whuugh.”
Some things are naturally black and orange like Halloween, often because they are poisonous. This is especially true for milkweed bugs (above) and monarch butterflies (below). The colors say “Notice me and stay away.”
Red admiral butterflies are orange-red and dark brown, almost black. Their host plant is nettle. Are they poisonous?
While visiting Arizona I noticed that one plant in particular attracted lots of butterflies. The plant above was covered in snouts (Libytheana carinenta) though only one shows up in my photo.
Eventually I learned that the plant is desert broom (Baccharis sarothroides), a dioecious shrub with very different male and female flowers (male on left, female on right below). The male flowers get all the attention from butterflies.
It’s hard to imagine how the female flowers become pollinated when nothing seems to visit them.
Next month after the flowers are fertilized the seeds will be ready to disperse. I’m sorry I’ll miss the period when the brooms look fluffy.