There are many types of natural ecosystems, each with distinct characteristics essential for understanding the abundance of life on earth.
Natural ecosystems refer to specific areas of the natural environment and are divided into two types: terrestrial (land) and aquatic (water). Terrestrial ecosystems include the tundra, grasslands, and tropical and deciduous forests, while the aquatic include reef and estuary ecosystems.
Each type of ecosystem has distinct characteristics and unique ways they sustain themselves and cycle energy and matter. This article will define natural ecosystems and highlight the key characteristics and essential differences of each type, an important part in being able to recognize them and understand how they fit into larger processes on earth.
In doing research for my first Environmental Systems course in graduate school, I found it difficult to find a detailed overview that compared qualities of the most important natural ecosystems in a clear way and distinguished ecosystems from related biomes. Hopefully this overview provides an eye-opening look at the amazing attributes of natural ecosystems that may even be present in your backyard!
What Defines a Natural Ecosystem?
Natural ecosystems are a specific area where populations of living (biotic) organisms interact with the nonliving (abiotic) physical environment in a certain way. As opposed to artificial ecosystems (for example, a farm), natural ecosystems do not need human intervention in order to exist or sustain themselves.
Functions of Natural Ecosystems
Natural ecosystems provide ecosystem services, which are benefits not only to organisms that call that ecosystem home, but to humans as well. Scientists refer to the process by which this happens as the flow of energy or matter. Energy ‘flows’ through the system when organisms are consumed by others in the ecosystem. You may have seen a food web diagram before, which depicts which organisms in an ecosystem consume others, thereby showing how energy in the form of food flows through the system.
Ecosystems can be quite large or they can be as small as a tide pool, but an important part of the living aspect of ecosystems is that they include what are called producers and consumers.
Producers are the organisms in the bottom of the food pyramid or food web diagram that create food for the other organisms in the web to eat. Most of the time, these are plants that use photosynthesis to grow and produce food for primary consumers.
Primary consumers are those organisms that consume producers, such as deer consuming vegetation in a temperate deciduous forest ecosystem. Secondary consumers, which make up the next level of a food web, are those organisms that consume primary consumers, and in our example would be the wolves or other carnivores that hunt deer. In some cases, there are tertiary consumers, and when these are the highest level predator they are often referred to as apex predators.
Net Primary Production
Another important aspect of natural ecosystems is the rate at which matter, or food, is produced at the base of the food web by the producers mentioned above. This is known as the net primary production (NPP). NPP is essentially a measure of the ‘metabolism’ of an ecosystem, and can vary greatly depending on the geographic location, the season, and even climate change.
In areas of the world where there are longer growing seasons, the NPP tends to be higher, and some ecosystems with the highest NPP are tropical rainforests. More temperate areas have intermediate levels of NPP, and the driest, coldest, most extreme ecosystems have the lowest NPP.
How Are Natural Ecosystems Classified?
Ecosystems are often grouped according to the biome they fall under (Tundra, Taiga, Grassland, etc.). Biomes are defined as a large community of similar plants and animals that all live in a certain climate. When looking at what classifies biomes versus ecosystems, biomes are mostly classified by climate, as opposed to ecosystems, which are usually classified by the organisms within them and their net primary productivity (NPP).
When researching ecosystems, you might find that the names of ecosystem types are often the same as the biomes. This tends to be confusing, as different sources tend to classify biomes and natural ecosystems a little differently, and often can overlap the two. However, I find that it is helpful to think of biomes as a descriptor of ecosystems - a way of more generally defining the region before specifying an ecosystem within it. For example, the desert is considered a biome in itself, but an ecosystem could also be referred to as a ‘desert ecosystem’. One refers to the larger region (biome) and one refers to the smaller area (ecosystem).
- Coniferous Forest
- Deciduous Forest
- Tropical Rainforest
Major Ecosystem Types
- Tropical Rainforest
- Tropical Seasonal Forest
- Temperate Grassland
- Temperate Evergreen Forest
- Boreal Northern Forest
- Woodland and Shrubland
- Tundra and Alpine
- Open Ocean
- Rivers, Streams and Lakes
What Are The Characteristics of The Natural Ecosystems?
One of the key characteristics that differentiates natural ecosystems from each other is their net primary production. Below are the main types of natural ecosystems and their qualifying characteristics. There are a lot of different ecosystems with slightly different characteristics, so I’ve also included a table with the most important ones so you can more easily compare these differences and similarities.
Ecosystems on land are referred to as being terrestrial, as opposed to those in marine or freshwater environments. All of these ecosystems exist on land, with the exception of wetland ecosystems, which are considered terrestrial even though they are submerged for part or most of the year.
Tropical Rainforests and Tropical Seasonal Forests
Tropical ecosystems are incredibly diverse, housing many species of plants and animals. Tropical rainforests are one of earth’s oldest natural ecosystems and exist on almost every continent. A well-known example of a tropical rainforest is the Amazon, which houses 16,000 tree species alone. Tropical rainforests are what are known as highly-productive ecosystems, meaning that there is a large amount of biomass, or food, produced at the bottom level of the food chain.
Producers that live in tropical rainforest ecosystems include many types of tropical fruit and canopy trees, grasses, and mosses. Consumers include parrots, monkeys, leopards and frogs.
Similar to tropical rainforests, tropical seasonal forests are also very diverse ecosystems, but are characterized by a slightly cooler dry season. Tropical seasonal forests have a relatively high NPP rate, but it is lower than tropical rainforests, and they cover a smaller area of the earth.
Producers found in tropical seasonal forests include ferns, orchids, and some deciduous trees. Consumers in these ecosystems include rabbits, tree frogs, bobcats, and small birds.
Temperate grassland ecosystems are characterized by cooler temperatures and wide open spaces with few trees. They are often found in places like North American prairies, and burrowing animals like prairie dogs call temperate grassland ecosystems home. Temperate grasslands have a medium NPP, with a lower productivity level than the savanna ecosystem but higher than the tundra or alpine.
Producers found in temperate grassland ecosystems include sagebrush, grasses, and sunflowers, while consumers include bison, foxes, grasshoppers, and rabbits.
Temperate Evergreen Forest and Temperate Deciduous Forest
Temperate evergreen forest ecosystems are characterized by lower rainfall and lower temperatures than the tropical rainforest, and is found in more coastal areas of North America and Eastern Europe, as well as areas of Australia and New Zealand. They generally have shorter summers and slightly longer winters, and are home to animals like caribou, owls and moose. Producers in these ecosystems include maple, oak, and beech trees. Temperate evergreen forest ecosystems have a medium NPP, lower than tropical rainforests or tropical seasonal forest ecosystems.
Similar to the temperate evergreen forest, temperate deciduous forest ecosystems are characterized by experiencing all four seasons, and are common in many parts of Europe as well as North America, China and Japan. Temperate deciduous forests have slightly higher NPP than temperate evergreen forests, and are home to animals like turtles, frogs, slugs, and other animals that can adapt to the changing of the seasons. Shrubs are common and trees like maple and birch are also present.
Boreal Northern Forest
The boreal northern forest ecosystem is one you might see labelled interchangeably with the ‘taiga’, which you might have noticed is one of the major biomes. Like I mentioned before, names for ecosystems and biomes are sometimes used interchangeably, but the taiga ecosystem will usually refer to a smaller, more specified area when used in practice than the taiga biome.
Boreal northern forest ecosystems are classified by a large presence of coniferous trees, or trees that produce cones like pinecones. Ecosystems classified as boreal have cold climates and a relatively low NPP, but not quite as low as more extreme ecosystems like the tundra. Aspen and birch trees as well as ferns are common producers in these ecosystems, and consumers include coldwater fish, lynx, and brown, black or polar bears, depending on where they are.
Woodland and Shrubland
As you might guess from the name, producers in shrubland ecosystems include more shrubs and short trees than other types of forests, but are not quite as dry and barren to be considered a desert. They have a medium NPP, which is lower during the noticeable dry season. Southern California, as well as parts of Australia and certain parts of Southern Africa contain shrubland ecosystems, and the flora and fauna present are well-adapted to droughts. Consumers in these ecosystems include antelope, rabbits, shrews, and hawks.
Desert ecosystems are similar to shrubland, but are generally harsher. Desert ecosystems can be hot, semi-arid, or coastal depending on the climate, but are characterized by their extremely dry environment and little rainfall. As you can imagine, deserts have low NPP due to the harsh conditions, which limit the types of producers that can grow.
These ecosystems can be found all around the world, with arid desert ecosystems being concentrated in places like Africa and parts of North America. The Sahara Desert in Northern Africa is the largest desert in the world, and is one of the hottest places on earth. Other types of desert ecosystems are found in parts of Asia and even Greenland.
Plants and animals that are able to survive in desert ecosystems have important adaptations that allow them to live without water for long periods of time. Producer plants that inhabit desert ecosystems include many varieties of cactus as well as drought-resistant shrubs. Consumers include foxes, rabbits, mice, scorpions, beetles, and coyotes.
Similar to temperate grassland ecosystems, one of the most prominent characteristics of savanna ecosystems are wide open spaces, also referred to as ‘open canopies’. Because the savanna does have similarities to other ecosystems, classification might differ depending on who you ask, but these are the most important characteristics.
Rainfall in the savanna usually only happens during one season, but despite this it has a relatively high NPP. Savanna ecosystems are very commonly found in areas of Africa, like the Serengeti, but are also found in parts of Australia and India. Producers in these ecosystems include many types of grasses as well as trees like the acacia tree or baobab.
Tundra and Alpine
Located toward the poles, tundra ecosystems can be classified further into arctic, antarctic, and alpine tundra ecosystems depending on where they are. Despite these differences, though, tundra ecosystems have some key characteristics including very low temperatures and a very short growing season as compared to other ecosystems. This cold weather, along with high winds that are also characteristic of these ecosystems, makes for a relatively low NPP since plants that can grow in these conditions are limited.
Tundra ecosystems can vary somewhat depending on the location, but types of producers that are common in the tundra ecosystems include arctic moss, lichens, arctic willow, and other resilient plants. Certain ecosystems may have less trees if they are harsher environments. Consumers found in tundra ecosystems include the musk ox, caribou, lynx, and wolverine.
Wetland ecosystems are also sometimes referred to as swamp ecosystems or marsh ecosystems depending on their characteristics, but I’ve grouped them together here - keep in mind, though, there are subtle differences between these three types and you might see them designated differently or even all grouped together depending where you look. Wetland ecosystems are usually considered terrestrial, but often exist on the boundary between terrestrial and aquatic ecosystems.
The main characteristic that defines wetland ecosystems is their low-lying nature and the fact that they are covered in water for most of the year. Because the water level can change in wetland ecosystems, they generally allow for more vegetation and are one of the higher-producing ecosystems in terms of their NPP.
Plant producers found in wetland ecosystems include grasses and cattails, shrubs, and trees like the River Maple or Swamp Oak. Consumers in this ecosystem include fish, frogs, snakes, water birds, and small mammals.
Below are the ecosystems that are not considered terrestrial, but are instead based in marine or freshwater environments. All of these ecosystems exist on land, with the exception of estuary ecosystems, which are considered aquatic even though they are considered transitional between land and water.
The open ocean is a massive place, and includes 99% of the inhabitable space on earth. Because of this, open ocean ecosystems can vary greatly in their characteristics, especially by zone.
Just as plants, or producers, on land use photosynthesis to create food for consumers in the ecosystem, photosynthesis is also used by organisms in the ocean. However, sunlight can only reach so far, and deep sea organisms are specially adapted to harsh, dark conditions. Therefore, characteristics of organisms at different levels of the ocean will vary.
In general, open ocean ecosystems exist away from any coastal area and away from the bottom of the sea, where organisms live completely surrounded by water. Despite this, the open ocean is highly productive, with a very high NPP.
One of the most common producers in the open ocean are phytoplankton, or microscopic marine algae, which feed primary consumers like jellyfish and shrimp. Secondary consumers include fish, and tertiary consumers include large well-known species like sharks and killer whales.
Reefs are another hugely important and highly productive natural ecosystem, and are even often referred to as the rainforests of the sea. Coral reefs provide food and shelter for many marine organisms including fish, and reefs can create massive ecosystems with very high NPP.
Similar to the open ocean, phytoplankton are producers in the reef ecosystem, along with some other types of algae and seagrass. Primary consumers are the coral itself (which feeds on zooplankton) in addition to animals like fish and turtles. Further up the food chain, consumers like jellyfish, seals and sharks are secondary and tertiary consumers.
Located close to their terrestrial counterpart, wetlands, estuaries are usually found near the boundary between the sea and the land, where freshwater meets salty sea water. Estuaries are a delicate ecosystem with high productivity or NPP. Seagrass, phytoplankton, and other algaes are producers for estuary ecosystems, and many species of birds and shellfish are consumers.
The Chesapeake Bay Estuary is one example of an estuary ecosystem in North America, but estuaries are found near almost any coastal area.
Rivers, Streams, and Lakes
The last type of natural aquatic ecosystem are those in rivers, streams and lakes. These are all considered freshwater ecosystems, as they are replenished by rainwater. The species of producers and consumers in these ecosystems varies depending on which river, stream, or lake ecosystem you find, but similar to estuary ecosystems, producers include algae and other microorganisms, mosses and lichen. Consumers vary but include fish, turtles, and crustaceans.
How Do Natural Ecosystems Compare?
As you can see, there are many types of natural ecosystems, and the more specific you get, the more types of ecosystems you can find. However, like I mentioned earlier, the living and nonliving characteristics of ecosystems are one of the main ways to tell them apart. Additionally, the net primary production (NPP) rate is another important distinguishing characteristic, as well as where these ecosystems are found. Below is a table that breaks down these important elements of terrestrial and aquatic ecosystems so you can easily compare them.
About THE AUTHOR
In addition to finishing my Masters in Environmental Policy and Management with a concentration in Energy and Sustainability, I have had extensive research experience. My undergraduate degree concentrated in Environmental Science, and I have been involved in multiple research projects including conservation and environmental research. My ability to look critically at information and understand scientific vernacular has helped me in communicating that information to others who have different backgrounds and strengths than my own. I love discussing topics in conservation, climate, and renewable energy and thoroughly enjoy writing about them every day.Read more about Ariana Guilak