Mosses and Ferns Drink From Waterfall Spray

Small plants grow in the spray zone around a waterfall

Biological Strategy

Mosses

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Cooperate/Compete Between Different Species

From parasitism to mutualisms, there are endless interactions between organisms in nature. Interactions between species that lead to a negative outcome for one species are known as competition. Cooperation occurs when organisms work together for the benefit of each organism or species. While competition often occurs over resources or mates, the more biologists have begun to look for examples of cooperation in nature, the more they have found. For example, around 90% of plants have a beneficial partnership with fungi. Fungi provide the plant with nutrients such as nitrogen and phosphorus, in exchange for sugars from the plant.

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Control Erosion and Sediment

Ecosystems must maintain their soils on site and prevent it from being washed away. Organic matter, minerals, and other nutrients in soil support organisms from microorganisms to the largest mammals. But because of the pull of gravity, water flows unless impeded. Therefore, the presence and actions of many, diverse organisms hold soils in place and slow water to allow sediments to settle out rather than be washed downhill. For example, in forests, downed logs that fall crossways to the slope efficiently slow water flow, trapping soils carried by the water and causing water to soak into the soil. In areas lacking logs and other structures, water can flow so fast that it cuts into the soil, causing erosion that washes the soil away.

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Capture, Absorb, or Filter Liquids

The most common liquid used by living systems is water, which they require to survive. But there are many other liquids that provide nourishment, play a role in defense mechanisms, or serve other purposes. Water varies in its availability; it is sometimes plentiful and sometimes very scarce or only available as fog or mist. To minimize the energy required to capture, absorb, or filter liquids, living systems have strategies that take advantage of the unique properties of the given liquid. For example, water moves from a gaseous to liquid state when it encounters a surface colder than the air. Plants in forests that experience fog and clouds more than rain have strategies that condense liquid water from moist air.

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Attach Temporarily

Living systems must sometimes, temporarily, stay in one place, climb or otherwise move around, or hold things together. This entails attaching temporarily with the ability to release, which minimizes energy and material use. Some living systems repeatedly attach, detach, and reattach for an extended time, such as over their lifetimes. Despite being temporary, these attachments must withstand physical and other forces until they have achieved their purpose. Therefore, living systems have adapted attachment mechanisms optimized for the amount of time or number of times they must be used. An example is the gecko, which climbs walls by attaching its toes for less than a second. Other examples include insects that attach their eggs to a leaf until they hatch, and insects whose wings temporarily attach during flight but separate after landing.

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Attach Permanently

A living system can conserve energy by attaching permanently to a particular site because it can take advantage of resources that come its way, rather than expending energy to move to resources. A permanent attachment, intended to last the lifetime of the living system, creates special challenges. For example, physical mechanisms, such as the anchor that holds a marine algae to the ocean’s bottom, must be able to withstand forces that can pull it off its substrate. Chemical mechanisms, such as a barnacle’s glue, must avoid both physical and chemical breakdown, such as being dissolved by water.

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Mosses

Division Bryophyta (“moss plant”): Mosses, liverworts, hornworts

Bryophytes are one of the oldest groups of plants, appearing more than 500 million years ago in the Cambrian Period. Mosses are non-vascular, non-flowering, water-loving plants, often cushioning the floor of forests in dense mats. Unlike angiosperms or gymnosperms, mosses do not have fruits or seeds––they reproduce through spores. Currently, there are approximately 12,000 known species of mosses and their relatives. Sphagnum moss has been particularly useful to humans, as a key element in peat, and as a dressing for wounds in traditional cultures and along the battlelines of World War I.

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Tiny plants cling to vertical rock faces in waterfall spray zones, capturing moisture and creating rich microhabitats by taking advantage of constant mist and cool temperatures.

Introduction

The Cascadia bioregion is known for its dramatic elevation shifts and abundant rainfall, giving rise to countless waterfalls that carve through basalt cliffs and canyon walls. Around these falling waters exists a hidden world—lush, miniature ecosystems that owe their existence to the constant mist produced by the falls.

On vertical rock faces near waterfalls, where soil is scarce and direct sunlight may be harsh, most plants cannot survive. But for a particular suite of organisms—mosses, liverworts, and filmy ferns—the constant moisture of the waterfall spray zone provides a perfect refuge. These organisms don’t just survive here; they create the foundation for layered ecosystems that support surprising .

The Strategy

Non-vascular plants like mosses and liverworts have adapted to thrive in environments with thin or no soil, and high humidity. In waterfall spray zones, they use their entire surface area to absorb moisture directly from the air and from the constant drizzle of mist. Their fine root-like structures (rhizoids) anchor them tightly into the tiny cracks and rough textures of stone, giving them a foothold in a vertical world.

The filmy ferns (from the family Hymenophyllaceae), which are more commonly seen in tropical cloud forests, also find a stronghold in Cascadia’s waterfall zones. These ferns have ultra-thin, translucent fronds that are only a few cells thick—so delicate that they can only survive where humidity never drops too low. These ferns unroll their fragile leaflets toward the light, using the spray to prevent desiccation and maintain gas exchange.

Together, these plants transform bare stone into green, sponge-like mats. Their structures trap water, shelter spores and seeds, and slow down evaporation, creating a stable microclimate on the cliff face. As the mosses and ferns mature, they build up layers of organic material, inviting other species into their community: water-loving insects, lichens, spiders, and even amphibians that cling to the moist walls.

These miniature vertical wetlands act as buffers—slowing runoff, filtering air, and protecting rock faces from erosion. Because they can persist year-round in the spray, even during dry summer months, they provide continuity in an ecosystem shaped by seasonality.

The Potential

These spray zone ecosystems offer powerful inspiration for sustainable design. The ability of mosses and filmy ferns to survive on vertical surfaces with no soil, drawing moisture from the air, suggests new ways to create self-watering “living walls” in urban architecture—especially in regions with fog or mist.

In ecological restoration, encouraging these plants to recolonize cliff faces near creeks and waterfalls can help stabilize fragile slopes, support insect life, and offer refuge for species during climate stress.

Their example also teaches a broader ecological lesson: even the harshest, rockiest corners of a landscape can become hubs of biodiversity when organisms are finely tuned to the nuances of place. In the mosaic of Cascadia’s habitats, the spray zone cliffs are small in size, but vast in ecological influence—green ribbons of life stitched into the fabric of falling water.

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How Life Creates a Land: Salmon, Waves, and Waterfalls

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High mountains, wild rivers, deep inlets, countless islands, and trees that reach to heaven—discover how they all come together to create a unique harmony of life in Cascadia.

Last Updated June 23, 2025

References

Magazine article

Ancient Green Moss, Climate, and Deep Time

Emergence Magazine | April 20, 2022 | Kimmerer, R. W.

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Reference

Journal article

Viability of Living Moss for Indoor Green Walls: A Study on Temperature, Humidity, and Irrigation

Sustainability | November 4, 2023 | Harald G. Zechmeister, Leonie Möslinger, Azra Korjenic, Erich Streit, Abdulah Sulejmanovski, Patrick Niklas Frank, and Esther Hummel

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Reference

Web page

Waterfalls and Biodiversity in British Columbia

Biodiversity of BC | February 25, 2009 | Goward, T. and Bjork, C.

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