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Lichens – Cuisine for Reindeer

Posted by Gary on February 8, 2016 in Lichens
This lichen often grows in large beds.
There are different species on this lichen found around the world.
Lichens are slow growing.

The caribou, also called the reindeer, is a herbivore. During the summer it eats willows and the abundant grasses and flowering plants on the tundra. Winter frost and snow kill the herbaceous plants and cover low growing shrubs cutting off an important food source for the caribou. This large hoofed animal is capable of sniffing out lichens beneath the snow where it will paw away the snow to find its major source of winter food – reindeer lichen.

Lichens are low in protein, high in carbohydrates so it provides the energy caribou need to survive the bitter cold. Caribou are not the only animal that eats lichens in the winter. Muskox and Dall sheep of Alaska, white-tailed deer of North America and the North American moose also eat lichens.

You need not travel to the tundra to see this lichen. I have found this lichen (Cladonia spp.) in the pine barrens of Long Island and here in Florida’s hardwood forests. Outside of the tundra, it often found in dry sandy soiled areas. Be on the lookout for reindeer lichen if you have similar a habitats in your area.

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Lichens – Litmus for Air Quality

Posted by Gary on February 5, 2016 in Lichens
Bearded Lichen grows on the bark of many species of trees.
Parula warbler uses these strands to construct its nest.
Because this lichen is bushy, it has a lot of surface area making it sensitive to air pollution.
There are many species of bearded lichen in the genus Usnea.

Each spring, the parula warbler constructs nests made of bearded lichen in the mature forests of northern U.S. and southern Canada. This lichen is so important to the nesting success of this bird that when the lichen disappeared because of air pollution in the mid 1900’s, it stressed the populations of this tree top warbler.

Lichens are highly valued bio-indicators of air quality. If the air is polluted, lichen species and density will decline. If air quality is good lichens become abundant. Lichens are hypersensitive to sulfur dioxide* emitted from the combustion of fossil fuels, auto emissions and some industries. This is because lichens absorb water and vital minerals from the air. Some lichens, like bearded lichen (Usnea spp.),  are more sensitive to air pollution than others.

A dramatic increase sulfur dioxide emissions occurred from the early 1900’s until the 1970’s. During this time many species of lichens disappeared from industrialized areas in the U.S. With rules put in place by the E.P.A., pollution decrease dramatically and many lichen populations rebounded and the parula warbler benefited.

Check out your local park to see if there is an abundance of lichens on the trees. If you see lots of bearded lichens and other similar “bushy” lichens, then breath deeply!

 

*Sulfur dioxide in the atmosphere combines with water to produce sulfuric acid resulting in acid rain. Sulfur dioxide is also spewed from erupting volcanoes.

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Lichens – The First Pioneers

Posted by Gary on February 2, 2016 in Lichens
Boulder with lichens.
Tree bark expands faster than the lichens can disolve the wood so no harm done.
Stump is decomposing with the help of lichens, fungi and mosses.
A variety of lichens will grow on rock.
Lichens help to decompose dead wood into soil.

One of the most active volcanoes of the world, the Kilauea volcano in Hawaii frequently erupts  with lava flows to the ocean. The lava hardens into new land where forces began to break down the igneous rock into a hospitable place for plants to grow.

In addition to the physical forces of weathering, lichens contribute to the transformation the barren land into a genial environment for plants. The lichen is the first organisms to latch on to the barren rock where it secretes acids that breaks down the stone  into fine sand granules. Decaying lichens and wind-blown dust bind with the sand to form a substrate that is favorable  to plants. It is a slow progression from bare rock to forest, sometimes taking centuries to complete.

Lichens are everywhere – in the dry deserts of Africa, the frigid tundra of North America and the frozen regions of Antarctica. But you need not go to these areas of extremes to find these organisms. You will discover lichens growing on fallen, decaying trees in your local park where they decompose dead wood. You may even see them on the bark of trees in your yard. Slow growing, lichens do not harm a healthy tree.

Think how barren and different the earth might be if it were not for lichens pioneering the way for plant life to evolve. We may not be here today if it weren’t for this tiny organism.

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Fifty Shades of Green

Posted by Gary on January 29, 2016 in Lichens

The winter woodlands is a dismal place with lifeless trees and shrubs, dried dead flowers and grasses and exposed decaying leaf litter and twigs. If you look beyond this bleak landscape, you will discover an intriguing world of plant-like organisms called lichens inhabiting the nooks and crannies of tree bark, fallen branches and boulders.

Although they often come in hues of green, lichens are not plants. They are two organisms – a fungus and an algae* – fused together to form a unique species. It is a partnership where  the fungus provides a place for the algae to grow and the algae provides food for the fungus.

There are different species of lichens depending on the specific combination of algae and fungus.  Some are leafy, others are crusty, many are shrub-like and others look like tiny plants. Although many of them come in various hues of green – gray-green, aqua green, pale green, olive-green and everything in between – some species are a variety of reds, oranges, yellows and browns.

I find lichens such fascinating organisms that I will devote several blogs on its role in the environment and relationship to wildlife. I hope you find them as interesting as I do.

 

*Another group of organisms, the cyanobacteria can also be a partner and sometimes organisms from all three groups can form a lichen.

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Skimmers Galore!

Posted by Gary on December 17, 2015 in Shore Birds

Florida hosts many species of birds in the winter due to its mild climate. For some birds the Florida peninsula is the gateway to South American wintering spots. For others Florida is the place to be.

One of my favorite local places to see winter migrants is a tiny beach on the Gulf Coast – Fort Island Gulf Beach. During  a recent trip there I was delighted to see 250 to 300 black skimmers flying in circles over the beach. A few descended upon the sandy shore and the rest followed. Just as the last of the flock set down, the first ones alighted to the air causing the flock to follow.  The skimmers continued to soar over the area, landing briefly only to take off and repeat the behavior.

Though this was an impressive flock of birds, I imagine, if I traveled back in time before the black skimmer was hunted for its feathers causing near extinction and before we encroached on its nesting habitat, the numbers of birds would be tenfold or more. Instead of hundreds in the flock there were probably thousands upon thousands of birds. And if someone stands here 50 years from now will they be wowed by the sight of  a meager dozen skimmers circling this small alcove.  Time will tell.

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