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Posts Tagged ‘common greenshield’

On Sunday afternoon, Birdgirl and I took advantage of an unusually mild January afternoon to visit the Perth Wildlife Reserve. It was a pleasant day to check out the 2.5 kilometer trail. Located on the Tay Marsh, the 257-hectare reserve was established in 1971. It is composed of 96 hectares of fields and forested land and 161 hectares of marsh. Unfortunately for Raven, no dogs are allowed, so poor Raven stayed at home.

The emphasis at the reserve is the protection of species at risk. Accordingly, the colourful signs along the trail introduce the hiker to some of these species. Unfortunately, it’s not always clear if the species referred to in the sign is actually present at the site indicated! The first sign we came to (which should actually be the last sign; we walked the trail in reverse) focuses on butternut trees (Juglans cinerea). We were uncertain which of the trees nearby might be butternut. None were marked as such and with no leaves, it was hard to be sure.

Butternut is a smaller and shorter-lived relative of the walnut tree. A little more hardy than the walnut, it grows farther north and east. It is more commonly found alone than in pure stands or groves. A sun-lover, butternut doesn’t tolerate shade. To help keep other plants at a distance, butternut, like walnut, exudes the chemical juglone, which can kill other plants whose roots come in contact with it.

Sadly, in recent years, butternut has been under assault by an introduced fungal infection, butternut canker. First observed in 1967 in Wisconsin, the canker has spread quickly. The disease has already infected 70 to 90 percent of the butternuts in Minnesota, Wisconsin, and eastern Ontario, and has now spread to the Maritimes. It is feared that, like the American Chestnut, which was virtually wiped out in just 40 years by an introduced chestnut blight, the butternut tree may also be on the road to oblivion.

The path led through a plantation of white and red pines. There was evidence of a Piliated Woodpecker (Dryocopus pileatus), but except for some cheerful chickadees, the woods were quiet.

Here and there, black knot fungus was conspicuous. Birdgirl wrote on Black Knot in an early post in February of 2008.

In the middle of the trail, we came upon a pile of feathers where a predator had made a meal of a bird. Who was the victim? Who was the perpetrator? For a full investigation into this mystery, visit The Marvelous in Nature at Murder in the Woods.

Many of the trees sported a variety of lichens such as this foliose lichen, probably Common Greenshield (Flavoparmelia caperata). As lichens are sensitive to poor air quality, a good display of lichens suggests the air is relatively free of pollutants.

While we were walking through the trees, we stopped to inspect some of the little black dots in the snow. Many were tiny bits of debris, but some hopped. Snow fleas! Birdgirl took some photographs of these, and added them to photos she had taken near her home. See her post on snow fleas here.

There was certainly no sign of any snakes. In fact, there wasn’t even much sign of the rock pile that the sign refers to. We finally noticed a snowy mound farther down the trail. A snake hibernaculum! Here’s Birdgirl’s post on a possible Rat Snake sighting last spring.

In this part of Ontario, split rail fences, or snake fences are common. The trail crosses back and forth through an old snake fence, giving evidence of the reserve’s former life as a farm. The fence makes a good runway for squirrels and a perch for birds. As they drop seeds and nuts around the fence, a hedgerow gradually grows up, providing more cover for small animals. At this point, we were about halfway along our hike. Tomorrow, I’ll finish the second half of our hike.

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It’s easy to miss lichens during the summer. At least here in the north, they have to compete with the riotous growth of green plants that have only a few short months to do their thing. Lichens really come into their own in winter, when the bare landscape lets them shine. When I was hiking a few weeks ago, lichens were among the most eye-catching subjects along the trail. Suddenly, with the trees bare of leaves, lichens are conspicuous everywhere.

When you start looking at them more closely, lichens are fascinating. For starters, a lichen is actually a two-part harmony of a fungal host and an algae. Sometimes a cyanobacteria also plays a role. Some twenty percent of the world’s fungi grow only as part of a lichen partnership. To put this symbiotic relationship very simply, the fungus provides shelter for the algae, while the algae provides food. The fungus benefits more from this relationship. While the algae could survive without the fungus, lichen fungi are never found growing alone.

Lichens grow on a variety of substrates: the ground (including decomposing logs), rocks (including surfaces such as roof shingles) and on trees. The two photos above show examples of a common rock lichen, rock shield lichens of the genus Xanthoparmelia

Rock shield is a foliose lichen, a lichen that looks like leafy growths divided by lobes. The lower surface is often differently coloured from the upper surface. Another example of a foliose lichen found on rocks is Rock Tripe (Umbilicaria spp). Rock tripes feature large, leathery lobes that look like they are peeling off the rock.

Here’s another rock tripe.

I also came across patches of reindeer moss (Cladina spp). It’s not a moss at all, but another lichen. Reindeer lichen is an example of a fruticose lichen, which have bushy or shrubby growth forms. As the name suggests, reindeer moss is an important food source for reindeer and caribou.

Reindeer moss grows over thin soils and rocks. Several different Cladina species may be found growing together.

Lichens that are very flat, appearing to be almost sprayed on a substrate, are termed crustose lichens. Powdery goldspeck (Candelariella efflorescens), which grows in small, round patches, is an example of a crustose lichen. Tree bark may feature whole communities with multiple species of lichens.

Some lichens only grow on specific tree species, while other lichens are generalists. Common greenshield (Flavoparmelia caperata) is a generalist that, as the name suggests, is extremely common.

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