⏳ Estimated Reading Time: 13 - 15 minutes

Explain how human activities affect biodiversity and strategies to combat the problem.

HIPPCO

In 1998, the IUCN came out with a report that stated that 23% (1141) of mammals are threatened, 12% (1226) of birds are threatened, and the status of other groups isn’t well known.

There is no doubt that a burgeoning human population has impacted global biodiversity. These impacts are felt on every continent and in virtually every biome. It is important to note that the health of a species is closely tied to its ecosystem, and minor environmental changes can have a large impact. As such, we should never underestimate our impact on the natural world. As ecologist Garrett Hardin once said, “You can never do merely one thing.”

Humans are adept at intruding on natural areas. Even if we aren’t specifically in a habitat, we tend to find a way to make our presence known. For example, lights on cell phone towers attract birds, causing them to collide with the towers. Additionally, between 1 million and 1 billion birds die each year from crashing into glass windows. Interestingly, at our last house, I got home from work one day and found a dead bird right outside one of our largest windows. All we could guess was that the bird had flown into the glass and died because nothing else was wrong with the bird – no blood, no feathers out of place, nothing.

Another example is sea turtle nests. Even though humans haven’t built on the sand of a beach, the lights from hotels, condos, and houses can distract sea turtle babies when they hatch. These hatchlings need to make it to the ocean during the night, however, lights from human buildings have caused them to walk the wrong way – towards the lights – rather than towards the ocean.

We've discussed HIPPCO (Habitat destruction, Invasive species, Population growth, Pollution, Climate change, and Over-exploitation) before. Now, let's dive into the details of each aspect of HIPPCO.

Explore the tabs below to learn more about each ecosystem threat. As you are studying for the AP exam, always think about how HIPPCO is affecting species.

H
I
P
P
C
O

Habitat Destruction

The “H” in HIPPCO is responsible for 36% of all known extinctions - the greatest single source of biodiversity loss. Habitat destruction can occur when habitats are fragmented, converted to other uses, simplified, or when humans intrude on these habitats.

Habitat fragmentation occurs when human areas dominant the landscapes. Human areas consist of a mosaic of different land uses, which results in small patches that have high contrast from each other. Additionally, reducing habitat size creates a greater proportion of edges. In general, species do not like to live at the edge of their habitat but prefer to live in the middle of their habitat. Habitat conversion is when natural areas are converted to farms, housing subdivisions, shopping malls, marinas, and industrial centers, to name a few. Remember, the agricultural areas that occupy 36% of land on Earth are inhospitable area for most species.

Habitat destruction has many faces. Deforestation for lumber products or clearing of forests for agricultural purposes results in millions of acres of lost forest each year. Building of roads and highways results in fragmentation of habitats which, in turn, results in biodiversity loss. Typically, larger species are lost first followed by smaller species.

Usually, habitat destruction is the result of the expansion or industrialization by humans. There are 5 main ways that we destroy habitats – buildings, draining wetlands, overgrazing, dredging, and clearing land. Let’s explore each of these a little bit.

Building 🏬 (click to reveal)

Humans build structures for living, working, and recreation. Every time we build a new structure, we must clear or disrupt a natural ecosystem for construction.

Draining Wetlands 🌿 (click to reveal)

Wetlands are important and productive habitats. Not only do they serve as a nursery for many species, but they also filter water from the land and protect coastal areas from erosion and flooding caused by storms. However, we often want to live in areas where wetlands are located.

So, we drain the wetlands and fill them with topsoil. Not only does this displace all of the organisms that live directly in the wetland, but it can also alter the patterns of water flow across the land, which can disrupt habitats indirectly connected to wetlands.

Overgrazing 🐄 (click to reveal)

A positive feedback loop of soil erosion: starting with "Loss of soil makes it difficult for plants to grow,” leading to “Increased erosion", and exacerbated by “Overgrazing." — **Overgrazing initiates a positive feedback loop, exacerbating the problem.**

The impact of the grazing on lands varies depending on the density of livestock, rainfall, and soil fertility. If overgrazing occurs on dry lands, the grasses can have difficulty regrowing, causing increased erosion. The increased erosion makes it more difficult for the grasses to grow, increasing the erosion. This is an example of a positive feedback loop.

This positive feedback loop can mean that the grassland can no longer support the species it had before the grazing started. If grazing occurs on forested land that is cleared for grazing, once the land is cleared, the organisms that used to live in that forest have nowhere to live and must move or die.

Overgrazing slows the growth of vegetation, reduces the diversity of plant species, leads to unappetizing (at least to the cattle) grasses dominating the landscape, increases erosion, and subjects the land to further damage by trampling.

Dredging ⛴ (click to reveal)

A barge is floating on clear blue water, carrying a large pile of rocks. A crane with a red arm is either loading or unloading the rocks. — **Dredging disrupts aquatic habitats.**

Dredging occurs when we remove the sediments from the bottoms of bodies of water and is done for several reasons.

If we need to clear a shipping channel to provide a deeper space for cargo ships, we must dredge the channel.

Dredging can also occur when fishermen drag nets across the bottom of the ocean, disrupting the sediment and the ecosystems at the bottom of the ocean.

The sediment and organisms that are removed due to dredging are typically not placed back where they came from, displacing the organisms in the sediment from their habitat or killing them because they are adapted to living at the extreme pressures of deep-sea environments and die when they are brought up to sea level.

Clearing Land 🪵 (click to reveal)

We need cleared land to build homes and businesses and to grow the crops we eat. We also clear land to mine for resources found deep within the land and for the lumber and other resources found growing on the land.

Unfortunately, clearing land destroys the habitat that was once on that land. The habitat becomes simplified. For example, even if a forest is maintained, but managed by humans, managers tend to focus on one or two specific species of tree that is cultivated by the managers. This results in a decline of species diversity, especially the animals that depend on trees that aren’t cultivated.

If the land is cleared completely, then the habitat that was once found on that land disappears, removing the habitat for all the species that once lived in that area.

Invasive Species

Invasive species can out-compete native species forcing them to become extinct or migrate to other habitats (if available!). One well-known example of an invasive species that has spread to waters in the United States is the zebra mussel.

Invasive species can take over niches previously occupied by native species and disrupt food chains. Invasive species are usually generalists, have many offspring, and usually exhibit characteristics of r-selected species. For example, non-native plants are difficult for herbivores to eat and can keep energy from passing up the food chain.

Population Growth

When the human population was small, impacts on biodiversity were minimal. As the human population grew from around 1 billion in 1800 to over 7 billion today, the impacts on the biosphere increased exponentially.

A graph showing the growth of the world population from 10,000 BCE to projections for 2100, with a line indicating the population size, with annotations for significant historical events and milestones. The graph highlights the Black Death pandemic and the expected peak of population at 10.9 billion in 2086. — **As the size of the human population has increased, so has our impact on the environment.**

The increase in the human population has increased the pressure on the natural environment due to resource depletion and habitat destruction.

Human population growth puts pressure on wild species because we take over natural areas for places to live, grow our food, build our structures, etc. Additionally, our lifestyle of overconsumption can drive population, habitat change, and other aspects of HIPPCO.

Pollution

The contamination of the environment by harmful substances, such as chemicals, plastics, metals, radiation, etc., that are released by human activities, such as industry, agriculture, transportation, etc. can affect the health and survival of wildlife, reduce the quality of habitats, and disrupt the biogeochemical cycles.

Climate Change

Global climate change can cause habitat loss via changes in temperature, precipitation, sea level rise, and ocean acidification and warming.

When habitats change, species that are adapted to living within the ranges of tolerances in that habitat are forced to move or perish. Climate change also results in shifts in the range of species.

As an example, if oceans warm, lobsters that depend on cold ocean water for survival are forced to try and find that cold water. If they can’t, they become extinct.

Overexploitation

ethical.

A vibrant red and orange snake with intricate patterns is slithering along a thin branch amidst lush green palm fronds in a tropical setting. — **The exotic pet trade is the 3rd largest illicit income source.**

The “O” in HIPPCO can stand for either over-exploitation or over-harvesting. Both indicate removal of a natural resource at a rate faster than it can be replenished by natural forces.

Humans have, in the past, removed so much of one species that the species eventually became extinct.

Examples of this include the passenger pigeon and dodo bird, both of which were hunted for their meat, feathers, and eggs at a rate faster than the population of either could reproduce.

One of the most destructive forms of overexploitation is the illegal trade in exotic species due to a growing fad for exotic pets. This trade generates $12 billion a year, which is the 3rd largest illicit income source (after drugs and guns). One way to stop overexploitation is to just not purchase wild-caught species.

A beekeeper in a white suit with a mesh face covering is inspecting a frame covered with bees. — **Domesticated species are less likely to survive changing environmental conditions.**

CITES 🐘 is an international agreement that aims to regulate the trade of species, ensuring that the trade is sustainable and ethical.

Domestication of species can lead to negative impacts. Honeybees and livestock are examples of species that have been domesticated.

As these species move further and further away from their formerly wild and native conditions, their ability to survive changing environmental conditions becomes compromised.

Essential Knowledge

HIPPCO (habitat destruction, invasive species, population growth, pollution, climate change, and over exploitation) describes the main factors leading to a decrease in biodiversity.

Habitat fragmentation occurs when large habitats are broken into smaller, isolated areas. Causes of habitat fragmentation include the construction of roads and pipelines, clearing for agriculture or development, and logging.

The scale of habitat fragmentation that has an adverse effect on the inhabitants of a given ecosystem will vary from species to species within that ecosystem.

Global climate change can cause habitat loss via changes in temperature, precipitation, and sea level rise.

Some organisms have been somewhat or completely domesticated and are now managed for economic returns, such as honeybee colonies and domestic livestock. This domestication can have a negative impact on the biodiversity of that organism.

Protecting Biodiversity

A ‘Habitat Conservation Area No Trespassing’ sign is posted on a barbed wire fence in an open field with rolling hills in the background. — **Conservation allows us to regulate and sustainably manage a resource or species.**

Ecosystems have a remarkable natural ability to regenerate, so they are considered renewable resources. However, we can cause trouble for ecosystems when we take more than the excess and deplete the breeding population of that ecosystem.

Some people only value species if they provide a service or are worthwhile to them in some way (instrumental values). Others understand the intrinsic value of species. The value of natural species and ecosystems can be categorized as follows:

Value as sources for food and raw materials
Value as sources for medicines and pharmaceuticals
Recreational, aesthetic, and scientific value
Value for their own sake

An important consideration is that we do not know all the instrumental values that every species can have for humans, so it is likely that there is a species that we think may not have a lot of value, but that is just because we haven’t discovered the use for that species yet.

President Roosevelt was the first President to understand the importance of protecting our natural resources. He thought that we should start setting aside unique and important lands and form areas known as National Parks. These areas would be protected from use by humans. He focused his efforts on protecting the land, not the species living on the land, but it was an excellent first step in preserving and conserving our unique ecosystems.

Conservation is when we manage or regulate the use of a resource so that it does not exceed the capacity of the species or systems to renew itself. Preservation ensures the continuity of the ecosystems and species, regardless of the potential utility.

Both are an attempt to protect the ecosystems and organisms around us from ourselves. But, why do we need to protect the earth from ourselves?

Once a species goes extinct or once an area of land is changed, we can’t really put the land or ecosystem back the way it was (restoration). So, we try to conserve and preserve ecosystems so that we are not tasked with trying to do the impossible – restoring an already altered ecosystem.

To conserve ecosystems, we need to reduce the amount of waste entering our ecosystems and reduce air, land, and water pollution in the ecosystems. Our goal with conservation is to attempt to reverse the effects of pollution and habitat expansion, reducing future harm to the ecosystem.

Some people believe we should only protect the species in question and others believe that we need to protect the species AND their habitat. The problem with only protecting the species is that usually these species require a specific habitat and if their habitat is not protected, the species will not survive.

A panda resting on a large grey rock, with its body relaxed and head laid down. — **Zoos and aquariums protect species and educate the public, but usually do not protect the species'' native habitat.**

Zoos, aquariums, and natural parks have also become places where we protect biodiversity. Originally, these places were just places to observe animals, but as protecting biodiversity has become more important, these places now have breeding programs to protect species and also get their animals from one another. For example, if a zoo has two or three Giant Pandas that are brothers and sisters, they may trade pandas with another park so they can establish a breeding program with more genetic diversity. This protects the genetic diversity of the zoo’s breeding population and also protects animals in the wild from being captured for a zoo. Zoos and aquariums are examples of solely protecting the animals or plants without protecting their native habitat.

In the United States, we have National Parks, wilderness areas, and other places where species and their habitats are protected. These areas are set aside as legally protected land.

And, of course, because there are always those who will not do the right thing unless there are consequences for NOT doing the right thing, legislation also protects species and their habitats. One way of protecting species through legislation is the Endangered Species Act 🐼. It protects species AND their habitat. Once a species makes it onto the Endangered Species List, the species, its habitat, and its food source are protected. This means that it is illegal to hunt, trap, kill, or otherwise harm the endangered species. In addition, the species habitat is protected from disturbance and the species’ food source is also protected. If you are caught violating the Endangered Species Act 🐼, you can be prosecuted with a felony.

In the United States, we also have National Parks, wilderness areas, and other places where species and their habitats are protected. These areas are set aside as legally protected land.

We can legislate compliance with environmental regulations by issuing fines to companies for NOT following regulations set in place by states or the federal government and offer tax breaks to companies that comply with non-required environmental regulations. For example, some companies are offered tax breaks for lowering their carbon emissions.

Essential Knowledge

Some ways humans can mitigate the impact of loss of biodiversity include creating protected areas, use of habitat corridors, promoting sustainable land use practices, and restoring lost habitats.

AP Exam Tip

You should understand HIPPCO and how these actions affect the environment.

You should also know the difference between conservation, preservation, and restoration and which is easiest.

You should know methods we utilize to protect the environment from ourselves.

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