What Good are Mosses?
Becky Smucker
TITLE: What Good Are Mosses?
AUTHOR: Becky Smucker, Bryologist
PERMISSION to publish granted by author.
I had a dear friend, recently passed, who once asked me after stumbling around a bit, "Yes, mosses are beautiful, but...what good are they?"
All of us who have spent any time looking at the natural world would agree that moss is beautiful, but without a closer look, may thin kof it as just the "green paint" or "green velvet" that grows on logs and rocks along creeks, in sidewalk cracks, and on old roofs. Mosses are small, so we can forgive ourselves for not having noticed that moss mats are composed of many strikingly different species that are intricately structured and individually beautiful. It takes a hand lens to begin seeing that they are plants with stems and tiny leaves, and indeed, fascinating plants to get to know.
Not only are there many species of mosses, but they often grow with another group of plants that are very distantly related but lumped visually with mosses, called liverworts, a group of plants that I had not heard of for much of my life. There are about half as many liverwort species in the world as mosses, and in the diverse woods of the southern Appalachians, they are about a third of the species we see as moss. Mosses and liverworts, together with the much smaller group of hornworts, are called bryophytes (i.e., mossy plants) by botanists, as they often share habitats and physical traits.
So let's reframe my friend's question to "Bryophytes, what good are they?"
Bryophytes are present nearly everywhere on earth except in the oceans, including in your yard. Liverworts, then mosses and hornworts, were probably the earliest groups of land plants, so they have much to teach researchers about the basic functions of all plants and how plants have evolved over the 400+ million years they have existed. They play important ecological roles, such as providing habitat for countless tiny creatures, including insects, spiders, water bears and many other microscopic animals. They are part of the cycling of nutrients, and are food for snails and other critters. Salamanders take shelter in larger mats of mosses in shady, wet habitats.
Bryophytes have no roots and are usually just one cell thick, so they absorb water and nutrients directly through their cell walls. Along with lichens, bryophytes are the first to grow on rock and disturbed soil, stabilizing and repopulating natural and human-disturbed bare surfaces. They are experts at drying out without being damaged, and then quickly reabsorbing water even from fog, and getting back to work photosynthesizing within minutes of rehydrating. They buffer the ebb and flow of water in their environment, and in larger mats can hold lots of water and help maintain moisture in the air.
So yes, bryophytes are beautiful and of value in and of themselves, but they are also beneficial to the habitats we depend on. They are worthy of our attention and respect. If you've never examined these tiny plants up close, get yourself a 10X hand lens and get started!
