What is Habitat Fragmentation, and How Does it Affect Animals?

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Many environmental issues threaten our animal friends today. Some of these problems are well-known issues that everyone is aware of, such as overhunting, habitat loss, and global warming.

Unfortunately, not all issues are as well-understood. Many environmental problems, such as habitat fragmentation, which is strongly linked to habitat loss, tend to go unnoticed. Not many people understand it, and fewer even know of the issue.

Habitat fragmentation is a major issue that is putting many species at risk of extinction.

Join us in Floofmania as we explain the meaning of habitat fragmentation and its causes and effects on the environment.  

Slender trees without leaves standing next to a dirt road at the edge of the forest with cut down logs and saw dust strewn around the treeline.

What is Habitat Fragmentation?

Habitat fragmentation is when large parts of an animal’s range is destroyed, leaving behind smaller, scattered habitats. As the name suggests, these areas become fragmented and separate from each other, making contact and traveling between them difficult, if not impossible, for the animals.

When habitat fragmentation occurs, the animals and resources existing inside are divided, leaving them cut off from their surroundings. Instead of having a single massive population, there now exists several smaller groups. This puts considerable strain on the ecosystem as it severely hinders its ability to support itself.

How is Habitat Fragmentation Different from Habitat Loss?

Habitat fragmentation sounds similar to habitat loss and can be seen as a form of the latter. Both phenomena involve the widespread destruction of an environment, but the difference is how the destruction happens. 

Normal habitat loss usually occurs in the fringes, where people begin pushing deeper and deeper into an environment, gradually changing it. Habitat fragmentation occurs when something cuts through the heart of an ecosystem and splits it apart.

Think of habitat as a pizza, with the animals being the toppings. When we talk about habitat loss, it is someone eating each slice one by one. The territory steadily shrinks, but it remains intact as all the toppings can still move around the rest of the pizza and interact with each other. 

With habitat fragmentation, though, that is when the pizza is sliced up and placed on different plates. Here each slice is now separated, and the toppings are cut off from each other.

Why is Habitat Fragmentation an Issue?

If the ecosystem still exists, albeit smaller, that shouldn’t be too much of an issue, right? Unfortunately, it is not that simple, as habitat fragmentation creates several problems. The two biggest ones are limiting a species’ access to resources and limiting their access to each other.

Animals Will Have A Hard Time Gathering Resources in Fragmented Habitats

Cut down trees as wide as the eye can see with a small cluster of trees standing in the middle of thre frame, and tree-grown hills far off in the distance behind a omnious sky.

One of the biggest problems with habitat fragmentation is that it leaves resources equally fragmented. In a single, large environment, animals have options for finding food; if they can’t find anything in one place, they can move to another area to search for food there. 

In the in a fragmented habitat, though, that is no longer the case as animals are now trapped in a much smaller area. Most animals will have to make do with their limited resources, which makes things like droughts, famines, and wildfires more devastating since it can more easily destroy their already-limited resources.

Animals that used to have an abundant source of food or water will struggle to adapt to these changes. Predators like wolves are known for hunting in vast areas and claiming them as their territory. If their habitat becomes fragmented, the pack is less able to sustain itself.

What makes this worse is that resources are not always divided evenly. Some habitat fragments can have disproportionately more food and water, while others can have no access to things like water or food.

Animals Cannot Interact with Each Other Between Habitats.

Habitat fragmentation isn’t just about divided pieces of land; it’s also about separated animal populations. 

The only way animals can interact with members of their species if they can reach them, so when their habitats become divided, there is little animals can do.

They either have to stay in their smaller habitat or try to cross into the other areas at greater risk. Both of these scenarios have consequences. If animals remain in their area, they are at higher risk of inbreeding and natural disasters, but if they leave, they also have a higher chance of getting hurt. Lose-lose.

Most species are not used to roads and towns, so they won’t know how to cross them and reach other territories. Even if they did, they are much more likely to get hurt or run into trouble with the people there.

While some creatures, like birds, are less affected, other animals will struggle with this change and may never be able to leave their little island habitat.

Fact: American badgers are a perfect example of animals having to deal with human environments. Every year, thousands of badgers are victims of road accidents, accidental drownings in drainage areas, and getting trapped in tight areas.

What are the Causes of Habitat Fragmentation?

Habitat fragmentation is a massive change for an ecosystem, and there can be multiple reasons behind it. The most common reason behind fragmentation is human activity, such as land development. While it’s true that humans are primarily responsible for this, mother nature has also been the cause of habitat fragmentation from time to time. 

What Are Some Human Causes of Habitat Fragmentation?

Some of the most common and disastrous forms of habitat fragmentation come from human activity, such as

  • Agricultural development
  • Construction of roads and railways
  • Land development

Agricultural Development 

As the human population grows, we require more crops to provide us with food and necessary materials. That means farmers clear up vast swaths of territory to make room for their fields.

It is important to remember that these farms aren’t just developed anywhere; they need the most fertile land. If that happens to be in the middle of a habitat, they will set up their farms there. 

The Great Plains was once a single, massive grassland that spanned hundreds of miles. As settlers moved in, much of the land was taken over for farmland. There weren’t many obstacles like trees or mountains, so they could quickly clear the land and begin planting. That left the remaining grasslands cut off from each other.

Fact: There were once vast forests in the Philippines. But due to a population boom, most forests were cut down to make room for more farmland. The only places that were spared were mountainous or difficult-to-reach places. By the 2010s, only 20% of the forests remained.
Blackened trees on a hill in the darkness.

Infrastructure Projects  

Infrastructure projects are also major culprits for habitat fragmentation, especially projects like roads and railways. Because of their purpose and design, these projects cut right through habitats, which, while helpful in bringing people together, separates animals.

Say there’s a forest, and the government wants to connect two towns on either end; rather than go around, which is longer and more difficult, they might just cut right through the middle of the woods to make for easier access. This leaves the forest cut into two sections.

While some roads are narrow, others can be incredibly wide, sometimes having up to eight lanes. This makes it incredibly difficult for animals to travel across without getting hurt.

Some roads can make it even more difficult by adding things like guardrails or clearing up space to prevent trees from falling over and blocking the roads. These make the fragmentation even more pronounced and make traveling difficult. 

Worse, animals already have a harder time crossing the road. Unlike people, animals don’t understand when it is or isn’t safe to cross, so they are more likely to get into accidents while crossing roads.

Many of these problems also exist with railways, but these can be even worse as the tracks might be fenced off to prevent animals from crossing entirely.

Wavy road seen from above, cutting through a forest landscape.

Housing Construction 

Housing construction in rural and suburban areas is another major cause of habitat fragmentation. 

Since creating a neighborhood involves massive changes to a wide area. People will need to drain swamps or clear up large sections of forests to make room for a community. 

Depending on how the developers design the projects, it can break up the ecosystem into smaller parts. Once these areas are complete, the houses will act as gaps in the environment, making crossing difficult as most people will chase off animals who enter their property. 

Can Habitat Fragmentation Happen Naturally?

Humans aren’t the only cause of habitat fragmentation; all that is required is a sudden and dramatic event, something mother nature is more than capable of providing.

Natural disasters like floods, fires, and volcanic activity can devastate an ecosystem, leaving large parts uninhabited. The affected areas are nearly impossible for animals to cross, effectively causing a form of habitat fragmentation.

The difference between these situations and human activity is that natural habitat fragmentation tends to be temporary. Floods recede, and fires die out, and when they do, the habits naturally reestablish and become connected again. It is rare for permanent habitat fragmentation to occur as a result of natural disasters.

What Are the Effects of Habitat Fragmentation?

Although the effects of habitat fragmentation are not as immediately visible as other environmental issues, they can cause some serious long-term changes to the environment and the species living in them.

Barren brown soil in the middle of what was once a forest, with freshly cut logs arranged to the side.

Inbreeding is More Common in Fragmented Habitats. 

With animals no longer able to leave their scattered ecosystems, it drastically reduces the number of mates they have access to. Without enough mates, it seriously affects a species’s genetic diversity and puts them at risk of inbreeding. 

As inbreeding gets worse, animals become more susceptible to diseases or genetic defects, and they might, in time, lose the ability to reproduce.

Animals Can Disappear Entirely in These Habitats.

One serious side effect of habitat fragmentation is localized extinction. A species’ population needs plenty of land and resources to remain healthy. Since the species in these fragmented habitats are more vulnerable to inbreeding, lack of mates, and lack of resources, they are much more likely to go extinct.

The limited resources mean increased competition as the members of a species will now fight more aggressively over what little food and resources there are available. Highly territorial animals are susceptible to greater competition which can decimate their populations.

Even if people were to try and do something, conservation efforts would be much more difficult in these areas. Instead of being able to treat the entire area as one ecosystem, efforts would need to be put in place in many smaller habitats.

The Edge Effect Can Manifest in Broken Habitats.

The “edges” refer to a transitional zone between two different ecosystems. So say there is grassland beside a forest, and the edge is where these two areas meet and transition into each other.

Typically, edges form gradually and naturally, making moving between the two ecosystems easy for animals. Edges are important because they allow for strong biodiversity for both ecosystems, as the animals from both habitats can interact.

The problem with habitat fragmentation is that the edges that divide the habitats are artificial and abrupt, meaning fewer species can live, hunt, or travel across them. That means there are fewer opportunities for the ecosystems to interact, which weakens biodiversity overall for both areas. 

This is known as the edge effect and turns each area into an island, where they cannot intermingle with the surrounding areas.

Habitat Fragments Tend to Be More Vulnerable And Lack Biodiversity.

Every habitat and territory is interconnected in the environment, so they rely on each other to survive. If an area is cut off, such as habitat fragmentation, it can become weak and wither away.

The main cause of that is the loss of biodiversity. Although we often think of different habitats as separate entities, they are all part of a larger environment, so a lot of mixing happens between them.

Animals can cross over to search for food, shelter, or mates. This allows for environmental biodiversity as different species can come and go. But when a habitat is difficult to reach like these fragments, fewer animals can do that, and the populations already there will struggle to survive.

This situation leaves the ecosystem fragile even under normal circumstances and makes it more vulnerable to natural disasters. When something like floods or forest fires hit, it can ravage the area, and without good biodiversity, healing can take much longer as there are fewer means to repopulate a fragmented environment. 

Large swaths of land with blackened tree stems ravaged by wildfires.

What Are Some Solutions to Habitat Fragmentation?

With the problems of habitat fragmentation becoming better understood, solutions are being made to mitigate some of the effects or even reverse the problems. 

Some Places Create Wildlife Corridors for Animals to Pass

Wildlife bridge with a grass-clad surface connecting a forest over a road, seen from above.

A popular solution to address habitat fragmentation is to create wildlife corridors. These pieces of land connect the different sections of an ecosystem to keep them intact. That way, animals can still travel to different areas and are not completely separated from each other.

When new building projects are proposed, these corridors are considered during the planning and construction to not seriously disrupt the habitat of the animals living there.

Fact: To allow fish to cross dams, some dams have ‘fish ladders', which are little pools that slowly ascend the dam to allow fish to travel up and down.

Governments Are Creating Stricter Laws to Prevent Habitat Fragmentation

Governments are becoming more aware of the problems of habitat fragmentation and are now trying to be more proactive in stopping it. They do this primarily by identifying critical habitats and creating laws that limit where and how much land can be used in new developments.

With these laws in place, governments can preserve ecosystems and ensure better planning that will not fragment habitats in the future.

Aside from just trying to limit habitat destruction, governments are also buying up these habitats and holding them as publicly owned land to prevent anyone from exploiting the ecosystem altogether. 

Some Efforts Are Being Made to Restore Fragmented Lands

Aside from trying to prevent future habitat fragmentation, there are also some efforts to reverse habitat fragmentation. Governments and conservation groups are buying up land in fragmented areas and repurposing it as restoration areas.

These projects can come in different forms, such as tree planting, removing obstacles that prevent animals from traveling between fragments, or even building wildlife bridges, tunnels, or corridors.

What Animals Are Affected By Habitat Fragmentation?

Many animals are affected by habitat fragmentation, but here are a few prominent examples of animals that have been badly hit.

The Dormouse Suffers From Habitat Fragmentation In The UK

The dormouse is the perfect example of how habitat fragmentation can affect a species in the UK. These furry creatures are only a few inches long and can only travel very short distances.

As roads and other projects were made, they cut off the dormouse from moving across its habitat by removing parts of the hedges and forests they used for shelter. 

Traveling beyond their immediate area without proper shelter became incredibly difficult and led to severe habitat fragmentation. Since the 90s, the dormouse population has declined by more than 50% due to the issue. 

Polar Bears Are Well-Known Victims Of Habitat Fragmentation

Polar bears, especially those in islands and archipelagos, have felt the strain of habitat fragmentation due to global warming. As temperatures rise, the ice in their habitat has started melting, and the seasonal sea ice has been hit hard. Sea ice is large chunks of ice floating in Arctic waters during winter.

Sea ice is an integral part of the arctic habitat as the ice allows polar bears to travel and hunt without spending long hours swimming. Without enough sea ice to use, the different islands are now cut off from each other, leaving the polar bears with a drastically shrunken range. 

Recent research has shown that polar bears are now suffering from issues of inbreeding and cannibalism as a result of the lack of resources and mates.

The Plains Bison Is Affected By Habitat Fragmentation 

The bison is an interesting case of habitat fragmentation because its issues are almost entirely artificial. Unlike many animals, farmers have domesticated bison, so most bison live in ranches.

While food and shelter aren’t an issue, the problem is that bison cannot leave and intermingle with each other, limiting the number of new mates. This captivity has led to many bison herds becoming inbred as they slowly lose their genetic diversity.

Some ranchers are trying to solve this problem by introducing a breeding program where fresh bison are rotated into the herds during the breeding season so there is more genetic diversity.

Author: Quade Ong

Hello there, my name is Quade. I have been a writer for three years but an animal lover for over two decades. I grew up in one of the most biodiverse areas in the world, which has given me the blessing of seeing all sorts of beautiful animals. Now I strive to learn not just about the animals I am from, but those all over the world!

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