Moss

Close up view of moss showing sporophytes

NPS

Spongy, Fragile Carpets

Go for a hike almost anywhere in Acadia National Park and you’re sure to see an often overlooked, yet important part of the Acadian ecosystem – mosses.

There are over 12,000 species of mosses that have been identified worldwide. Differentiating between the many moss species can be challenging without the aid of a high-powered microscope, but with a small hand lens or even the naked eye, we can look closely and start to appreciate the beauty of these plants.

Looking from afar, mosses can add a beautiful and lush appearance to many of Acadia’s forests. Walking through the woods amongst the trees and mosses can produce a serene sense of calm and help us to understand our place in nature.

Characteristics

Look closely at a bed of moss and you’ll start to see an entirely new world opening up. The interesting and unique shapes of mosses let us imagine a planet with strange trees dominating the landscape. Mosses provide habitat for insects and other small creatures. Look for any length of time and you’re bound to find spiders and other invertebrates hiding among the moss. With the aid of a microscope, you’ll be able to find one of the common moss-residents, the tardigrade (commonly known as water bears or moss piglets). But what exactly makes a moss a moss?

One of the most distinguishing characteristics of mosses Is that they are non-vascular. This means they lack the tissues that many other plant species use to transport water and nutrients from roots to stems and leaves. Without vascular tissues, mosses do not have the support structure to grow tall like many other plants, and instead grow flat and low to the ground.

Mosses are very opportunistic plants, able to grow on rocks, trees, and along stream beds. The biggest factor for a moss’s survival is moisture. Without an adequate supply of water, mosses will dry out, not be able to reproduce, and eventually die.

How does moss reproduce?

Mosses reproduce in an unusual way. Unlike many other plants, mosses do not reproduce with seeds. Instead, they reproduce with spores, like fungi or ferns. Looking closely at mosses, one can see the sporophyte, with its capsule containing spores for reproduction.

 

Isopod (Oniscus asellus) in moss

NPS Photo by Jack Byrley

What role does moss play in the ecosystem?

Moss is a very important part of the forest ecosystems in Acadia National Park. Moss is great at retaining water after rainfall, and when things dry out, moss provides extra moisture that it slowly releases into the ecosystem. Moss also contributes to stabilizing soil. It reduces soil erosion in areas where it grows.

Beyond that, moss acts as shelter for small animals like shrews and mice, while also providing a food source for many of the smaller creatures in the forest, like slugs.

How can we protect mosses?

Though mosses are abundant in Acadia National Park, they are also quite fragile. Whenever possible, avoid stepping on moss or other vegetation. Instead, stay on trails or walk along durable surfaces like rocks and sand.

What is Liverwort?

Liverwort, like moss, is a non-vascular plant. Acadia is home to several species of liverwort- some resemble moss with tiny leaves, while others have a flat, papery appearance. Liverwort may reproduce either asexually or with the aid of spores. It can be found growing in damp environments on soil, bark, or rock. It aids in decomposition.

 

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