What is biodiversity?

Biodiversity, Guardians of the Seeds, Outdoors

This summer at Coastal Maine Botanical Gardens, we are celebrating the variety of life that fills all corners of the forest. With the help of our giant trolls, we can discover how crucial biodiversity is to the health of the forest and learn how to be better stewards of this important ecosystem. But what exactly is biodiversity and why does it matter?

Biodiversity is resilience.

Biodiversity is the variety of all life on Earth and most commonly refers to the number of different individual organisms found in an area. However, biodiversity can also be measured at many different levels. It can be larger than the individual—like the number of different ecosystems in a given area—or smaller than the individual, like the number of different genes in a population. Biodiversity provides us with everything that makes life on Earth possible—clean air and water, fertile soil, medicines, fuels, materials, shelter, places for recreation, and a stable climate.

This variety of life gives our planet the resilience to weather challenges and changes. When we lose that complexity and variety, we lose ecosystem stability and balance because all organisms are interconnected. In other words, without that complexity, a bad storm or new disease can devastate an entire ecosystem because there are no “backups” for the affected organisms.

Forests are made of interconnected individuals that rely on each other for survival.

Forests are home to 80% of the world’s terrestrial biodiversity, meaning they are more biologically diverse than any other land-based ecosystem. Forests stay healthy because their biodiversity provides stability to the ecosystem.

All the individuals—insects, plants, mammals, reptiles, fungi, amphibians—are interdependent. If one species disappears, it could change the way the entire forest is connected. Caterpillars help balance out the number of plants by eating their leaves. Birds and bears eat caterpillars, keeping them from devouring too many plants. Decomposers return nutrients to the soil by eating the organisms that have died.

Who is in Maine’s forest web of life?

Trunk and branches of the northern red oak tree, Quercus rubra

Quercus rubra by Bruce Kirchoff.

Northern red oak, Quercus rubra

Oaks like the northern red oak support more wildlife than any other trees in the Northeastern forest. An oak can produce over 3 million acorns in its lifetime, which more than 100 different animals depend on. Over 500 different caterpillar species eat oak leaves, and those caterpillars in turn become food for hundreds of animals, from birds to bears and everything in-between. And each year the leaf litter, if left unraked, protects the soil and replenishes nutrients

White trillium flower against forest background.

Trillium Flower by David Joyce

White trillium, Trillium grandiflorum

Spring ephemerals like white trillium bloom in early spring before the deciduous trees towering above them have fully leafed out. By doing so, they can take advantage of this rare period of direct sunlight. After just a few weeks, the plant will die back to the ground completely, waiting safely underground until the next spring. Many spring ephemerals have specially coated seeds that attract ants. After eating the coating, the ants discard the rest of the seed and inadvertently disperse the plant farther than it could go by itself.

Pileated Woodpecker sitting on tree trunk

Pileated Woodpecker by Sunny.

Pileated woodpecker, Dryocopus pileatus

The pileated woodpecker is Maine’s largest woodpecker. Listen for its whinnying calls or the echoing drumming on tree trunks as it hunts for food. They primarily eat carpenter ants and other wood-boring insects, leaving distinctive rectangular holes behind.

A red fox stands in the snow, looking off to the side.

Red Fox, f. by Kelly Colgan Azar.

Red fox, Vulpes vulpes

The red fox is the most widely distributed carnivore in the world and lives most commonly in habitats that are a mixture of field and forest. They are solitary hunters and survive primarily on a diet of mice and voles, which they hunt using their characteristic high pouncing technique.

A spotted salamander lays on moss.

Spotted salamander (ambystoma maculatum) by smashtonlee05.

Spotted salamander, Ambystoma maculatum

The spotted salamander is an amphibian native to Maine, living in forests near freshwater wetlands. Each spring, in order to reproduce, mature male and female salamanders migrate from the forest, returning to the seasonal vernal pools from which they hatched. There is a unique symbiotic relationship between the salamander eggs and a particular green algae (Oophila amblystomatis). The algae take waste and CO2 from the developing egg and produce oxygen that helps salamander larvae grow.

White ghost plant stalks emerging from dark soil.

Ghost Plant by Joshua Hurd.

Ghost pipe, Monotropa uniflora

The ghost pipe is a parasitic plant that doesn’t make its own energy through photosynthesis like most other plants do. Instead, it uses mycorrhizal fungi to tap into surrounding trees’ roots, stealing some of their nutrients. Because it doesn’t photosynthesize, it doesn’t need to produce chlorophyll, hence the plant’s ghostly white color.

Green, hair-covered caterpillar Io moth) clinging to leaf and twig.

Io moth caterpillar (Automeris io) by Malcolm Manners.

Io caterpillar, Automeris io

Io caterpillars were once very common in southern Maine and New England forests, feeding on the leaves of many different kinds of trees and shrubs like maples, birches, alders, and willows. However, their populations have declined significantly in New England, perhaps because of the release of a parasitic fly that was meant to control the populations of the invasive gypsy moth, Lymantria dispar.

A birch polypore shelf fungus attached to a birch log laying on the forest floor.

Birch Polypore – Fomitopsis betulina by Björn S…

Birch polypore, Fomitopsis betulina

The birch polypore is a bracket fungus that grows almost exclusively on dead or dying birch trees. The brackets, or fruiting bodies, emerge annually from the dying trees although the dried “shelves” may persist on trees for many years. The brackets are technically edible, although they can be tough and have a bitter, earthy flavor.

Preserving forests is important.

We envision a sustainable future in which humans support the forest’s biodiversity through responsible use of its resources. Despite technology, our society relies on healthy forests for resources such as clean air and water, food, medicine, fuel, and building materials. Approximately 90% of Maine is forested—the most of any state in the United States. These forests filter our air and water, prevent flooding and erosion, provide sustainable building materials, support livelihoods related to its resources, and provide us with places for recreation. We can protect these forests, vital to Maine’s culture and economy, by helping to protect the biodiversity within them and finding a balanced way to enter the forest’s web of life without totally destroying it.

Everyone can participate in conservation.

The root cause of biodiversity loss is population growth and overconsumption. We are in the midst of the sixth mass extinction on Earth, with reports showing that we have lost 60% of the global biodiversity in the last 40 years. This loss of life is caused by human action, through the expansion of agriculture and industry, overexploitation through hunting and fishing, the introduction of invasive species, and pollution. The trolls are here to remind us that we can change this course. There are many ways to get involved and join the trolls as guardians of the forest.

Contribute to research by participating in community science projects and documenting the biodiversity in your own backyards and communities. The first step to preserving biodiversity is being aware of what there is to begin with. Some of our favorite community science projects include the Forest Ecology Research Network, Signs of the Seasons phenology monitoring, eBird, Great Backyard Bird Count, Project Feeder Watch, Maine “Big Night” amphibian monitoring, and iNaturalist. You can also search for more in your areas of interest at SciStarter.com.

Protect the biodiversity you know you have by fostering wildlife habitat in your yard and controlling introduced weeds and pests. Help maintain Maine’s wetlands by conserving water, reducing irrigation, and not draining water bodies on your property. Consider donating property to land trusts.

Engage on a larger scale and amplify your voice by advocating for policy change that protects forests and their resources. One good place to start is the Natural Resources Council of Maine, who advocate for policy that protects, restores, and conserves Maine’s environment like waste and recycling reform, clean energy, and endangered species protection.

Want more ideas from the trolls about how to discover and support forest biodiversity? Check out the Teachings of the Trolls here.