Spruce Budworm & Balsam Fir

This is a Balsam Fir that killed by Spruce Budworm (Choristoneura fumiferana) about 30 years ago. This picture was taken in North Mountain, CB, March 2010.

While at North Mountain, located in the Cape Breton Highlands, we observed some Balsam Fir that had been destroyed 30 years previous by the spruce budworm (Choristoneura fumiferana). Now you might look at the picture taken and think this spruce budworm outbreak back in the 1970’s was terrible news for Balsam Fir and it was, but it was also part of this Balsam Fir’s life cycle. You might be interested to know that spruce budworm outbreaks occur periodically and frequently enough that they are considered part of the natural cycle of the maturing of Balsam Fir. Spruce budworm outbreaks occur on average every 35 years so since the last outbreak reached its peak in Nova Scotia 1976 we are due for another outbreak in the next few years.

Spruce budworm is an extremely destructive native insect which affects Balsam Fir stands in Cape Breton significantly. Balsam fir, well known for its attractive features as a conifer, is marred by spruce budworm outbreaks.

Spruce budworm usually lay their eggs on the under surfaces of needles of the host tree where the larvae will overwinter. In the spring when buds begin to swell, the larvae emerge from their silk shelter “hibernacula” and start feeding on needles and buds. Newly hatched budworm larvae bores into the needles and expanding buds of Balsam Fir and feeds. The needles are then severed and turn brown giving affected Balsam Fir’s a burnt or scorched appearance. If spruce budworm populations are high, significant damage can be caused. Since they eat the Balsam Fir foliage, the tree cannot photosynthesize and without this vital energy source, it dies. During spruce budworm outbreaks the larvae can destroy all of the new foliage and they sometimes feed on the buds and shoots resulting in the Balsam Fir becoming stunted, dead, or have dead tops. Not all affected Balsam Fir die during a budworm outbreak. Many survive the outbreak and can regenerate enough to only become damaged or marred. After more than a year of heavy defoliation, individual trees begin to die.

Although Balsam Fir is most frequently affected, other trees can be killed when spruce budworm populations are high. Other suitable hosts include spruce, Tamarack, pine and Eastern Hemlock.

Natural factors such as adverse weather, disease, predators, and parasites help keep budworm populations under control. Heavy outbreaks of spruce budworm may be attributed to favourable weather, adequate food sources, and suitable overwintering sites for the larvae. These budworm aren’t all bad either - some species such as woodpeckers and nuthatches actually benefit from the Spruce Budworms effect on forests.

I'm Lichen These Lichens!

What could be a better way to study the interactions between Cape Breton species than a perfect example of symbiosis? Symbiosis is the mutualistic relationship between two different species where each species gains some benefit from the interaction. The species discussed here are lichens. I'm sure everyone reading this has seen lichens at some point during a walk through the woods and not known what exactly they're looking at.

Lichens are composed of a fungus and a photosynthetic symbiont (photobiont) such as algae or cyanobacteria living in a special biological relationship called symbiosis. The fungal component of lichens is responsible for absorbing nutrients and structural support of the lichen. The algal component uses photosynthesis to produce carbohydrates or energy. Lichens can be classified based on their structure into 3 groups: crustose - crusty and flat; foliose – leafy; and fruticose – shrubby. We most often see lichens on trees but they can also be classified based on the locations in which they are found. The 3 groups are: corticolous – tree bark; saxicolous – rocks; and terricolous – soil.

Commonly known as Old Man's beard, this is a fruiticose lichen, Usnea sp. This picture was taken on Coxheath Mountain Wilderness Trail, Coxheath, NS in May 2009.

The most important use of lichens has to be as monitors of air quality. It has been known for over 140 years that lichens are extremely sensitive to air pollution and therefore make excellent indicators for changes in atmospheric quality especially in highly urbanized and industrialized regions. In an area where the air quality is extremely poor you won’t find any lichens because a rise in pollutant levels in an area kills the lichens living in that area. To understand how this works you need to have an understanding of the delicate structure of lichens. The sensitivity of lichens can be attributed to their ability to absorb chemicals rapidly from air and water. It is also their composition as a symbiotic relationship between two components that determines their sensitivity to pollutants because if a pollutant affects the well-being on even one component, say the fungus, this throws off the balance of the symbiotic relationship and the partnership breaks down and the lichen dies.

More Usnea sp. found in Northside East Bay Trail. Photo taken February 2010.

Some pollutants are especially harmful to lichens such as sulphuric acid, nitric acid (both components of acid rain), fluorides, ozone, hydrocarbons, and metals. Some lichens are more sensitive than others making them more conspicuous indicators of a change in air quality because they will disappear first from an area. These more sensitive lichens include the fruticose species such as Usnea, Ramalina, Teloscistes, Lobaria, Panaria and Nephroma. Usnea, seen in the photograph above, was found by our natural history class several times in regions throughout Cape Breton along the Louisbourg lighthouse trail, Coxheath Mountain Wilderness Trail, Northside East Bay and along the trail at Gillis Lake Falls. I have personally found this lichen throughout Cape Breton and this is an indicator of our excellent air quality in most areas of the island. A difference in lichens can be found within Cape Breton Island between areas that are more industrialized such as Port Hawkesbury where there is a very high level of air pollutants to areas in the highlands where there is basically no industrialization at all to areas such as Whitney Pier which may have been affected in the past due to pollutants from the now closed Sydney Steel Plant which closed in 2000 and an increase in lichen diversity may be found.

Usnea sp. growing on a tree in Northside East Bay. Photo taken February 2010.

Invasive Species in Cape Breton

The Atlantic Bay Scallop (Argopecten irradians) is an invasive species to Cape Breton. This species can be recognized by its nearly identical, deeply ribbed fan-shaped shells with a distinctive wing-like hinge. The shell color has quite a range from blue-black to orange, white or reddish brown. The shell we found in Dominion Beach had a blue-gray color that was almost purple. Their shells grow to approximately 2.5-3 inches in length.

http://www.projectufo.ca/drupal/Atlantic_Bay_Scallop

There are 4 sub-species of the Atlantic Bay Scallop - A. irradians irradians has 17-18 ribs and can be found the North shore of Cape Cod to New Jersey, A. irradians concentricus has 19-20 ribs and can be found from Maryland to Georgia and Louisiana to Tampa. It is also rarely found in Jersey. A. irradians amplicostatus has 12-17 ribs and can be found from central Texas to Mexico and Colombia. A. irradians sablensis has 18-21 ribs and is an extinct species. Valves can be found on Sable Island dating to times of warmer waters (1800 years ago).

Scallops feed by filter-feeding. They trap, absorb and ingest floating dead and decomposing plant and animal matter. Since what they feed on doesn’t negatively impact any particular species it is more important to observe what feed on this scallop. I’m sure many of us, including myself, were first introduced to scallops when they were served up on a plate. That is, humans are predators of this species along with starfish, wading birds, seagulls, pinfish, lightning whelks, cow-nosed rays, and crabs are among its numerous predators.

The habitat of the Atlantic Bay Scallop is usually eelgrass beds (Zostera marina) on sandy and sandy-mud bottoms. They prefer areas where the salt content is high and the water is calm. The range of this species extends from the Gulf of Mexico all the way to Cape Cod and now, more recently, in Nova Scotia. Their shells have been found at Dominion Beach and Big Glace Bay beach over the past few years. In Cape Breton, there have been live sighting along the coast near Cheticamp and Lingan Bay along with shells found at Dominion Beach and Glace Bay Beach. “It is possible that the introduction of the Atlantic Bay Scallop into Cape Breton waters is a result of the aquaculture of this species. Several areas in Nova Scotia (unlike Cape Breton) have water temperatures warm enough to support the development of juvenile Atlantic Bay Scallops. It is possible that adult scallops have escaped from aquaculture captivity and have entered our waters.” (Project UFO, 2008). While on a field trip to Dominion Beach we found evidence of this invasive species when we found the blue-gray shell that was either washed ashore or leftovers from some bird’s meal.

Black Knot Disease on Pin Cherry

http://www.gov.mb.ca/agriculture/crops/diseases/images/fac48s00a.jpg

We found Pin Cherry (Prunus pensylvanica) in several locations on our field trips but mainly within one specific habitat. Since Pin Cherry enjoys sunlight and open areas it can often be found along the edge of a forest and field or clearing. We found Pin Cherry at the Lingan Wind Farm, near North Mountain Beach in Neil’s Harbour, and along the Northside East Bay trail, among other places. The black lumps we refer to as Black Knot resembles a charcoal-like gall is actually a fungus! It can be found upon cherry, chokecherry, plums, and prunes. In our case we viewed it occurring on Pin Cherry. The lumps of Black Knot are a fungus (Apiosporina morbosum) which acts a parasite and feeds upon the tree and disfigures it. The symptom of this infection does not become apparent until the winter of the second season after the tree has become infected. The infection can sometimes occur as early as 20 months before signs of growth become apparent. The symptoms of an infected tree appear as tiny galls on the branches or as swellings of the shoot tissue. This gives the shoot a cork-like appearance. Once the infection has set after the second winter and it enters its second season, the knots develop quickly. If you ever notice black knot appearing to have a white or pinkish tinge you may be observing another fungus developing on the older portions of Black Knot. The fungus develops when infection takes place during wet periods and the young green shoots and wounded tissues of the parasitized plant are the most susceptible to infection by the spores of the fungus. If any of your cultivated trees exhibit signs of developing Black Knot or Black Knot is already mature and present and you would like to remove it for aesthetic reasons and to save your trees you should know that the best time to remove the knots is in the winter which is prior to the release of spores.

Pin Cherry (Prunus pensylvanica) bark. Photo taken in Northside East Bay, January 2010.

Red Maple in this corner and White-tailed Deer in the other

Throughout nature you will find an infinite amount of connections between different organisms. I've decided to make these interesting, and often unexpected, interactions the focus of this blog.

Today's topic is Red Maple (Acer rubrum) and White-tailed Deer (Odocoileus virginianus).

The locations in which Red Maple can be found extends from forests, stream banks, and swamps to fields, valleys, and dry ridges. It is one of the most abundant and widespread trees in North America and can be found in areas that have been clear-cut in the past. The White-tailed Deer used Red Maple as both a food source and a form of shelter. The twigs of the young Red Maple trees are reddish with white lenticels that have small red, rounded buds that White-tailed Deer feed upon. This food source is highly desirable by deer and it has been shown in studies that deer are aware of the trade-offs between the different energy concentrations of their food sources. The current seasons growth is an important source of food, especially in the winter, because it can affect reproduction and litter size, body condition, and winter survival when other important food sources may be scarce. The winter is also the mating season for deer.

Red Maple seedlings are negatively affected by being a popular food source for deer because this may affect their survival rate by causing the young seedling to become stunted or deformed. In areas where there are excessive deer populations, the reproduction of Red Maple is almost completely suppressed. This frequent browsing of Red Maple may result in a significant change in the composition of forests in an area.

White-tailed Deer aren't the only suspect in the case of over-browsed Red Maple seedlings - Snowshoe Hares are another culprit for the same crime. You can easily tell the different between a Red Maple bud that has been browsed by a Snowshoe Hare or White-tailed Deer because the hare clips the stems clean and the deer break or tear the stems so they appear jagged.

Location Location Location

Here are some great locations around Cape Breton I've recently visited with my Biology class for winter field trips:

Dominion Beach - Collect shells along the shore and look for boring holes that may have been made by the coniverous Moon Snails.

Glace Bay Beach/Fish Plant/Glace Bay Park - This is a good location for practice using your bird guide. Keep an eye out for American Black Ducks, American Wigeon, Mallard Ducks, Bufflehead, Long-tailed Duck, cormorants, Northern Pintail, Great Black-backed Gulls, Double-crested Cormorant, Herring Gulls, and Iceland Gulls. In the park we also saw some Austrian Pine.

Louisbourg Light House Trail - You might see Long-tailed Ducks, guillemonts, scoters, Grey Seals, Bald Eagle, Common Eider, Bufflehead, Crowberry, Juniper, Rose Hips, and Balsam Fir.

Coxheath Mountain - Keep an eye & ear out for woodpeckers. At the top of the mountain at the cabin which is always open there is some bird seed. Use the seed to try and attract some Black Capped Chickadees to feed out of your hand. You can gain their attention by making a phish-phish sounds - much like you would to a attract a cat. Many of the trees on the way up are labelled. Note the difference in the type of forest as you approach the top of the mountain.

Lingan Wind Farm - You might see Cormorants, Bayberry, Crowberry, Snowshoe Hare tracks, Iceland Gull, White Birch, and White Spruce.

Northside East Bay Trail - Some plants seen here includes Eastern White Pine, White Spruce, Trembling Aspen, Heal-all, Yellow Birch, Balsam Fir, Amelanchier sp., Pin Cherry, White Ash, and White Birch.

Cape Breton University Trail - Look out for tracks in the snow - we found Red Squirrel and Snowshoe Hare near the opening of the trail and throughout. Wintergreen, Goldthread, and Labrador Tea are some plants that can be found here that might peak some "flavorful" interest.

First Post!

Welcome to my blog! This is the first post and I'd like to explain the purpose of this blog. This is my "Interesting Project" for a course I'm currently taking at Cape Breton University titled Natural History of Cape Breton. All of the information I'll be posting on here is related to species found on Cape Breton Island and I chose to write about them because I find them interesting. The focus of this blog is interactions between species and basically their impact upon each other.

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