Living organisms such as Birds, Mammals, Amphibians, Reptiles, Invertebrates, Plants and Trees along with non-living features of an area such as climate, weather, soil and water together form an ecosystem.  Ecology is the study of how theses living organisms interact within the non-living features of the ecosystem.  The State of Maine has a land area of over 22 million acres that stretches 3 degrees of latitude from south to north and changes in elevation from sea-level along the Atlantic coastline to 5,267 feet at the peak of Mount Katahdin.

Maine’s geographical boundaries support diverse ecosystems ranging from tide-pools to tundra, fresh water lakes and rivers to forests, and Pine Barrens to peat bogs.  Within any of these areas are many different smaller groups of plants and trees that are called communities.  Birds and other animals are adapted to use these ecosystems to meet their habitat needs.

For example, Red Squirrels feed on conifer cones whereas Gray Squirrels eat nuts so you would then know from their habitat needs which ecosystem each would be more likely to be found in.  Both species of squirrels are found throughout a large part of the State, but not everywhere since favored food sources do not grow everywhere because of limitations such as climate and soil.

Maine supports a large number of Marine Invertebrates that rely on a habitat of salt water such as snails and crabs, and other invertebrates such as the Black Fly that needs a habitat of running fresh water.  These non-living features support living organisms that further support larger animals which prey upon them.  The food chain is one basic part of an ecosystem that transfers energy from the plants and phytoplankton up through feeding levels of herbivores and then to carnivores and at various stages decomposition of plants and animals return inorganic matter back into the ecosystem to be recycled.  The food chain maintains the overall health of the living organisms through the consumption of pests and weaker animals that minimize disease and overpopulation which can lead to unhealthy ecosystems.

One way of defining ecosystems is to determine the type of forest trees or lack thereof.  In the State of Maine there are 3 distinct forested areas:

Northern Hardwood – Spruce mixed Forests typical of the Northeast Mixed Forest, Acadia and the Canadian Maritimes.  This area experiences cooler growing season temperatures due to latitude and proximity to the ocean with poorly drained soils.

Spruce-fir and Northern Hardwood Forests typical of New England Mixed Forested Mountain areas where conifers dominate the wet lowlands and Hardwoods dominate the dry high elevation ridges leading up to mountain summits.  This area typically receives significant snowfall and experiences colder temperatures throughout the winter months.

Broadleaf Forest in the southwest and coastal area typical of the Eastern Seaboard where temperatures are more moderate and soils provide better drainage.

There are 24 Ecosystems found within Forests, Open Uplands, Peatlands, Freshwater Shorelines and Tidal areas.  Features of these Ecosystems are found here…

These ecosystems further support 104 Natural Communities of which features of the Natural Communities of Plants and Trees are found here…


A Key to determining Natural Community Types are found here…

The Maine Natural Areas Program (MNAP) is part of the Maine Department of Conservation which oversees the conservation of Maine’s diverse and unique ecological diversity.  They provide extensive resource information including both online and print publications such as Natural Landscapes of Maine by Susan Gawler and Andrew Cutko that can be found here…..


A terrific resource that explains the science of the underlying history of Maine’s forested landscape is The Changing Nature of the Maine Woods by Andrew M Barton with Alan S. White and Charles V. Cogbill that can be purchased here…..

An excellent resource offering insight to Maine’s ecosystems through the formation of the geological and soil base is Roadside Geology of Maine by D.W. Caldwell that can be purchased here…..