Epiphytes: Sub-Groups, Habitat, and Ecosystems

Epiphytes are organisms that can be found growing on the surfaces of plants, rocks, and other natural surfaces. 

Although a select few epiphytes are parasitic, meaning that they damage the plant they are living on, the majority of epiphytes only benefit from plants in terms of support rather than nutrition, which makes them a unique and fascinating group of organisms to study. 

There are various sub-groups of epiphytes, from algae to fungi. We’re going to be discussing all of these sub-groups in this brief guide to epiphytes, in addition to typical epiphyte habitats and how these organisms contribute to the ecosystem!

Why We Need Epiphytes 

If you’re wondering why we’re talking about epiphytes in the first place, it’s because these organisms contribute much to the natural world. Without them ecosystems in the wild would not be able to thrive as they do. 

Epiphytes are a nutritious food source for many other animals, as we’ll explore in further detail later. Not only that, but these organisms can even serve as a habitat for certain animals. 

Epiphytes can help to provide a canopy to minimize the erosion of soil. They are an essential part of nutrient and water cycles, and they are essential for forest biomass. 

Main Epiphyte Sub-Groups 

As we will see shortly, epiphytes can be divided into many different sub-groups, but to keep things simple for now, we can separate these organisms into 3 main subcategories. These are: 

Hemi-epiphytes 

Hemi-epiphytes are an example of epiphytes that don’t need their host plant for the entirety of their life cycle. While they spend a portion of their life living on the plant, they will gradually make their way to the ground. 

One of the most common examples of this is a vine that gets long enough to reach the ground and finally grows roots. These roots then help the vine to get nutrition from the soil as well as water because of the vascular tissue that they contain. 

Holo-epiphytes

Unlike hemi-epiphytes, holo-epiphytes need to use a plant as a host for the duration of their life cycle.

They are able to do this because of the structures that bind them to the plant while facilitating the absorption of water, minerals, and nutrients from that plant.

Because holo-epiphytes get everything they need from their host plant, they have no need to grow toward the ground. 

Proto-epiphytes 

Proto-epiphytes are similar to homo-epiphytes because they don’t have the features present in hemi-epiphytes that would allow them to live independently of their host. These epiphytes specifically depend on plants for nutrients.

Certain fungi that can be classified as epiphytes are part of this sub-group. 

Where Do Epiphytes Live?

When it comes to epiphytes, the general rule is that if you can find other plants in an environment, epiphytes are probably growing there as well. This rule applies on a global scale, meaning that epiphytes can be found all over the world. 

As we discussed earlier, epiphytes can be divided into further sub-groups. The most effective way to introduce these other sub-groups is to divide them according to the different habitats and plants that they grow on. 

Bird’s Nest Fern

Bird’s Nest Fern is a type of fern that gets its name from the fact that it can often be mistaken for a bird’s nest. 

These ferns don’t produce any flowers and are green all over, with sizable leaves and no stem. Their method of reproduction involves spores. 

Bird’s Nest Fern is found in many areas of the world, although it favors temperate and tropical climates. It is present in the highest numbers in Africa, Southeast Asia, Australia, Hawaii, and other countries with similar climates.

The ideal environment for this type of epiphyte has plenty of humidity but it prefers to receive sunlight indirectly. 

When observed in paleo tropical climates, Bird’s Nest Ferns confine themselves to branch surfaces and tree bark rather than the leaves.

Several invertebrate arthropod species use these ferns as their habitat, in addition to nocturnal animals such as bats, and the presence of these epiphytes is essential for biomass as well as biodiversity in the environment. 

Bird’s Nest Fern epiphytes can also be found in the Malaysian rainforest, where they use various trees for support and sustenance.

In this environment, the epiphytes serve a very important function: they catch debris as it falls and use this debris for food during the decomposition process. 

They have the capacity to grow to more than 200 kilograms from the nutrients provided by the debris, and the bigger they grow, the more animals these ferns can shelter. When these animals die, they, too, become food for the epiphytes. 

Hymenophyllaceae

600 different filmy fern species have been identified within the Hymenophyllaceae family.

You can differentiate a Hymenophyllaceae epiphyte from other epiphytes by their leaves, which are extremely thin – so much so that you can almost see through them. 

They don’t produce flowers, but unlike Bird’s Nest Ferns, they do have stems, although the stems are also very thin and delicate. These stems are very important because the vascular tissue inside them allows nutrients and water to be absorbed. 

Most of the time, you will find Hymenophyllaceae in tropical climates; specifically, in forest habitats.

These epiphytes can be hemi-epiphytic, meaning that they don’t need a plant host for their whole life cycle and can thrive in the soil, while others will remain connected to a tree or plant from the start of their life cycle until the end. 

Just as there is diversity between Hymenophyllaceae epiphytes in terms of their relationships to other plants, these epiphytes are also diverse in the sense that they absorb nutrition from plants and soil in different ways.

Some have roots, for example, which means that they can draw water from the soil and distribute that water throughout the plant. Others simply absorb water through the leaves of the plant.

Some of these ferns are called shade epiphytes because they grow low down on tree trunks so that they can climb up the trunk and avoid the shade cast by the canopy. This makes for more effective photosynthesis. 

It’s important to note that not all Hymenophyllaceae are epiphytic, but roughly 60% of them are. 

Epiphytic Vines

Next, we have epiphytic vines. These vines are actually the most common and widespread sub-group of epiphytes, so they’re one of the most important groups to learn about. 

Vines like these are most often found in the rain forests of tropical climates, specifically the Amazon rainforest. This gives the vines access to plenty of water and moisture from humidity. 

Most of the time, epiphytic vines have thin stems and roots that are grounded in soil. These stems allow the vines to climb up host plants so that they can access sunlight for photosynthesis as well as nutrients and water. 

These epiphytes can’t live without the support of other host plants because their stems are so thin.

Therefore, epiphytic vines are classified as vascular epiphytes because they attach themselves to trees and sometimes other plants and use their vascular tissue to absorb the nutrition they need.

The roots of epiphytic vines aren’t like the basal roots that you might expect. Instead, the roots protrude from the stem and will attach themselves to the trunk of the host tree. This helps to compensate for the weakness of the vines’ stems.

Epiphytic vines can be either herbaceous or woody. Herbaceous vines don’t grow as long as woody vines, only growing by a matter of centimeters, whereas woody vines can reach impressive lengths and climb up tall trees. 

Sometimes, epiphytic vines can begin their growth journey at the ground without using any other plants for support.

Lianas are an example of this. When the vine begins to get longer and the stem starts to struggle to hold itself up, the vine will attach to the trunk of the tree. 

Flowering Epiphytes 

Some epiphytes are classified as flowering plants! These make up just 10% of vascular plants worldwide, and you may also hear them referred to as angiosperms. 

Flowering epiphytes can be divided into 2 main groups:

Tillandsia 

Tillandsia is an entire genus of plants, and over 500 plant species exist within this genus. They are most commonly distributed across South America and North America. 

These epiphytes are part of a group of epiphytes with specialized roots. These roots allow the epiphyte to attach itself to the branches, trunks, or stems of host plants instead of the soil.

They also have outgrowths that protrude from their leaves. These growths are called trichomes, and when observed closely, they look like hairs.

These tiny structures facilitate nutrient and water absorption through the epiphyte’s leaves, hence why the roots of the plant are primarily designed for attachment rather than nutrient intake. 

Tillandsia are able to survive in inhospitable climates where the weather is typically dry and very hot. This is partly due to their trichomes because these structures permit the epiphyte to absorb nutrients from the air!

Specifically, dew, mist, and fog contain a lot of moisture, and this is really important for these epiphytes. Additionally, trichomes can help to reflect a certain amount of sunlight from the epidermis of the plant.

This prevents all of the water absorbed from evaporating, keeping the epiphyte healthy for longer, even in hot and dry conditions. 

Another strategy that Tillandsia use to survive in hot environments is that they grow high up on plants so that they can absorb as much energy as they need through photosynthesis, but they are also exposed to more air because they aren’t stifled by the canopy.

This increased air exposure means that they can absorb more nutrients and water to combat the potentially dehydrating effects of sunlight exposure. 

Tillandsia behave similarly to Bird’s Nest Ferns in the sense that they catch falling debris, including dust in the air, and derive nutrition from it. 

These epiphytes reproduce easily and relatively quickly by producing seeds, which are then carried on the wind and distributed across the environment. 

Orchids 

You might not have known that orchids are epiphytes. Sometimes, they are called mat epiphytes because they grow in clusters on tree branches and end up looking like mats.

Orchids can also be found growing on tropical and subtropical shrubs, either on the stems or the branches.

Orchids, in particular, have a very interesting relationship with a specific species of fungi: mycorrhizal fungi. While the epiphytes are in the early stages of growth, these fungi enter the plant’s roots and facilitate better nutrient intake, resulting in faster growth. 

Unlike the vines we discussed earlier, certain types of epiphytic orchids have thick, short stems. These are known scientifically as pseudobulbs and the orchids that have them are mostly found in climates with temperamental weather conditions.

The pseudobulbs allow the orchids to conserve water while storing nutrients and minerals. 

Epiphytic orchids also have meager roots, which are special roots with the ability to draw water out of plants and store that water whilst keeping the orchid attached to the host plant. 

Fun fact: roughly 68% of all vascular epiphytes fall under the category of orchids. Epiphytic orchids are holo-epiphytes, which means that they depend on host plants for their whole life cycle and don’t exist independently of other plant species.

Unlike some other epiphytes, which reproduce using spores, orchids pollinate and reproduce from their seeds.

Fungi

Not all species of fungi are classified as epiphytes, but many are! Fungi that grow inside plant tissues are called endophytes, while those that live on the surfaces of plants are, of course, called epiphytes. 

The fungi kingdom comprises eukaryotic organisms which don’t have the ability to produce food for themselves. The scientific term for such organisms is heterotrophs. 

Now, unlike other epiphytes which can absorb nutrition and water from the air while also photosynthesizing, fungi don’t have this option. Fungi need host plants to provide them with nutrients since they have no way of making their own food.

While they do attach themselves to plants in order to survive, they don’t significantly harm their host plants. 

Bryophytes

Bryophytes are non-vascular epiphytes. This means that they don’t have the phloem and xylem that make up the vascular system of other epiphytes. These epiphytes don’t have roots, either, which means that they aren’t able to support themselves very well. 

Some bryophytes are not actually epiphytic, but the majority are. Those that are epiphytic will grow on the surfaces of host plants, with most growing on trees.

The main types of bryophytes are arre mosses, liverworts, and hornworts, and we’re going to talk about these in detail now. 

Epiphytic Liverworts 

Epiphytic liverworts are similar to mosses in the sense that they don’t have a vascular system. They are also not flowering plants, which means that they can only reproduce by distributing spores.

However, this is a very effective method of reproduction which allows a single liverwort epiphyte to reproduce over a large surface area. 

Epiphytic liverworts typically either grow on large trees, where they attach to the bark, or on plants that have tied and started to decay as long as they are in sufficiently shaded areas. 

These epiphytes can be found in large numbers in temperate climates, including rainforests, which provide the specific weather conditions that liverworts require.

In rainforest climates, epiphytic liverworts usually live on tree bark because this gives them access to sunlight, water, and other forms of nutrition. 

Hornworts 

Hornworts can easily be identified upon close observation because they look different to other bryophytes. They have elongated sporophytes.

Their behavior is also easy to identify as well because they are usually found growing on rocks and in soil rather than trees or host plants. 

The only hornwort genus that is epiphytic is the Dendroceros genus, and these are the only hornworts that you will find using other plants for nutrition and support. 

Epiphytic Mosses

Another type of bryophyte that is often epiphytic are epiphytic mosses. These mosses don’t produce flowers, so they reproduce through spores.

This is a type of plant that seeks out other plants of the same species to grow together with. That’s why when you see moss, it’s typically in a mat-like cluster. 

Epiphytic mosses can be found in a variety of natural habitats, from forests in coastal regions to tropical forests. They favor cool and moist environments, and in the right conditions, they grow quickly on tree trunks, branches, and on top of tree roots.

From there, they will often spread out and cover the ground around the tree, which is why many forest floors seem to have a covering of moss. 

These mosses are non-vascular, but they can still take in water through their simple leaf structures since they like to grow in areas with plenty of moisture. They don’t have roots, so moisture is absorbed straight into the body of the epiphyte.

Which Animals Do Epiphytes Feed?

We mentioned earlier that one of the most important roles of epiphytes is to act as a source of food for animals that share their habitat.

It is interesting that epiphytes can feed other animals since some epiphytes absorb nutrients from animals that die while using the epiphyte as a habitat. This demonstrates the cyclical nature of life within any ecosystem. 

While bryophytes can be very toxic to some animals, certain animals have digestive systems that are able to withstand and even derive nutrition from these plants. 

Mosses are typically used as a food source by caribou, reindeer, and pikas. With that being said, epiphytic mosses are not a primary food source for any animal, simply because they don’t provide very much nutritional value. 

Liverworts are not particularly nutritious for any animal species, either. Despite this, rodents such as mice and other, larger animals like caribou will eat liverworts if food is scarce and they come across them. 

Filmy ferns, such as Bird’s Nest Ferns, are a good food source for many small animals. Rabbits like to snack on these epiphytes, as do deer. Insects and worms also get nutrients from these plants. 

You won’t usually see land animals using hornworts as a food source, but they do play a role in water-based ecosystems because some fish are able to eat them. 

Orchids are a popular food source for a variety of animals, both vertebrate and invertebrate. Insects, in particular, like to feed on orchids. These include caterpillars, snails, and grasshoppers. 

Finally, epiphytic vines are edible to some animal species as well. Birds and herbivorous animals will eat certain parts of epiphytic vines and will also help these epiphytes to reproduce by distributing their seeds through their feces. 

Frequently Asked Questions 

Do Epiphytes Need Soil?

Because some epiphytes are rooted directly into soil while others aren’t, the question of whether or not epiphytes need soil can be complicated. 

Basically, if an epiphyte is able to absorb water directly from the air, they may not need soil. These epiphytes usually won’t have roots, or if they do, they will be adapted specifically to the purpose of attaching to a tree or other surface rather than absorbing water.

On the other hand, if an epiphyte is less able to draw nutrients from the air, it will have to take water and nutrition either from the plant it is attached to or from the soil. 

Either way, the host plant will be deriving part of its nutrition from the soil, so whether the epiphyte gets its nutrients from roots in the soil or through the bark or leaves of the host plant, it ultimately needs soil, even if the need is indirect.

Do Epiphytes Harm Trees?

In most cases, epiphytes are not harmful to trees. In fact, many epiphytes contribute to the ecosystem and benefit the plants they grow on.

However, when epiphytes grow on plants in large numbers, they can eventually damage the plant. This is especially true when epiphytes grow on seagrasses. 

Most of the time, any damage caused by epiphytes is due to the fact that they can end up blocking sunlight or access to other forms of nutrition if they provide too much coverage. 

How Do You Care For An Epiphyte Orchid? 

While many epiphytes are not considered to be desirable plants, some, like orchids, make lovely house plants.

If you want to care for an epiphyte orchid, you’ll need to select a plant that is already a few years old. This will mean that you don’t have to wait years for the plant to bloom.

Choose a lower-maintenance orchid like a moth orchid or a corsage orchid for the best chance of success. 

You’ll need to choose somewhere with the correct amount of light for your specific orchid species. Some need low natural lighting conditions, but every orchid can benefit from fluorescent lighting for around 12 hours daily.

You should also keep the temperature between 75 degrees Fahrenheit and 80 degrees Fahrenheit during the day, although it should be allowed to drop to between 60 and 36 degrees Fahrenheit overnight.

It’s a good idea to invest in a misting humidifier to mimic tropical conditions. 

Remember that many epiphytes struggle to support themselves, so make sure to tie your orchid to another piece of plant material such as tree fern or cedar with a piece of string. 

Water the soil regularly so that it stays moist and add some fertilizer on a monthly basis. Ensure that your chosen medium allows for air to circulate near the roots. 

Final Thoughts 

Epiphytes are interesting organisms that contribute to various ecosystems while relying on other plants for nutrition and support. They are an important food source for several animal species and also provide animals with reliable habitats. 

As this article has demonstrated, epiphytes come in many different forms and use different methods to survive, often in challenging environments.

Whether they are vascular or non-vascular, homo-epiphytic or hemi-epiphytic, all epiphytes are valuable contributors to natural habitats across the globe.

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