Biodiversity – Definition, Importance and Major Threats

Nature’s balance is dependent upon diversity of life – biodiversity.

Our understanding of our planet is shifting to a view of Earth as a single living organism with all organisms and life processes interdependent. This understanding is coming rather late in the game though.

In the name of growth and progress we have unwittingly destroyed much of the nature encompassing this enormously important abundance of life forms that binds everything together. What’s worse, even when we are aware of the natural interconnectedness, we still continue to remove species.

Scientists are ringing the bell: if the destruction of natural habitats continues unchecked, we are ensuring our own extinction. Step by step we are bringing our species closer to this danger. But there is still a chance to revert this process. For that, we need to understand the essence of life that allows species to flourish. Biodiversity.

So, what is the definition of biodiversity and what is the importance of it in our life?

The definition: what is biodiversity?

Biodiversity (also biological diversity or biotic diversity) is the rich variety of life in every ecosystem on earth.

The term “biodiversity” refers to every living thing: plants, animals, bacteria and even humans. Biodiversity is often spoken of as having three different levels that can be examined:

• species diversity
• genetic diversity
• ecosystem diversity

When discussing biodiversity in an area, we are often talking about the animals. This includes even amphibians like frogs or salamanders, reptiles and various insects like spiders, ladybugs or butterflies. We are also considering birds and fish, as well as mammals like monkeys, tigers or raccoons.

Biodiversity includes plants, not just the colorful and exotic ones like orchids, but even the smallest grasses, mosses and lichen. Sometimes scientists studying biodiversity like to count the tiny animals in the soil and on dead plants, not just worms but microorganisms that we cannot easily see but are hard at work making the soil rich.

All of these are examples of the different species within an ecosystem. But that is not all, biodiversity is richer than that!

What is genetic diversity of species?

Biodiversity can also be assessed on a smaller level, on the level of genetic diversity. Genetic diversity looks to the variety of genes within a species. This is important because a greater variety of genes within a population helps species to better adapt to a habitat.

For example, if an area has been deforested and the remaining animal community is small, the animals do not have much choice in mating. In a larger population, one monkey, for example, might mate with another monkey outside its family that has genes that protect it from a disease like COVID.

If a monkey can mate with another who has a gene providing resistance to COVID, there is a good chance their offspring will be resistant to COVID too and the population has a better chance of surviving.

On the other hand, if there are no monkeys in the small remaining area with a resistance to COVID, then the entire population will be wiped out if even just one is exposed to COVID and the disease spreads to the rest.

What does the ecosystem diversity mean?

Some scientists take a step back instead of closer when considering biodiversity.

That is the third level called ecosystem diversity. An ecosystem is a biological community living within a certain geographical area. It can be, for example, all of the life within a jungle, a marine ecosystem, a desert or a grassland.

And one geographical area may have several ecosystems. For example, the area of Tropical Andes is rich in ecosystem diversity as it includes mountains, cloud forests, grasslands, woodlands and even tropical rainforests.

How do we measure biodiversity?

We talk of areas being rich in biodiversity. What exactly is meant by that?

When we speak of biodiversity, we must first define the group that is studied. We might assess genetic diversity within a species, or species diversity (for example monkeys vs birds), or even functional groups like deep-rooted plants or nitrogen-fixing ones. We can go even large scale in assessing whole ecosystems like desert vs jungle.

This might bring a question. Why do we want to measure biodiversity in the first place?

The key knowledge: areas rich in a biodiversity of species are healthier, more resistant to diseases and more resilient. Therefore, we measure biodiversity to get an idea of the current state of the natural environment.

The evaluation of the species richness and species evenness

Let’s presume that we are considering species within a specific area. We look to the number and variety of species living in the defined area: the plants and the animals – mammals, reptiles, amphibians, birds, microorganisms and if relevant aquatic life.

For example, when we examine a particular ecosystem for the number of different species, we count:

• 1 species of frogs
• 1 species of butterflies
• 4 species of snakes
• 5 species of beetles
• 3 species of fungi
• 1 species of birds
• 4 species of mammals
• 17 species of vascular plants
• 3 species of trees
• 2 species of moss

This measure is called the species richness.

But if we are trying to evaluate whether we are looking at a diverse and healthy ecosystem, while on its face it appears quite diverse, these numbers do not necessarily give an accurate portrayal of the area.

It may have 17 species of vascular plants, but if even just a one of them is an invasive species that spreads a poison through its roots to fungi that support remaining plants, the ecosystem may be teetering on the brink of collapse.

Or there may be forty snakes and just three frogs living in that ecosystem, meaning the frogs may soon be history. Or just a few insects and forty frogs, which may result in the frogs losing their food source very soon.

Accordingly, evenness of the species in the ecosystem must also be considered.

The Simpson’s Diversity Index & the Shannon-Wiener Index

Sometimes there are too many species in a given area to count each one, so ecologists get an estimate by stretching transect tapes across the area and then placing a quadrat (a frame with a known internal area) at regular intervals. They then count the species within the frame and extrapolate to the area.

A number of different diversity indices are used by ecologists, the most common are the Simpson Index and the Shannon-Wiener Diversity Index which consider both species richness and evenness.

These indexes use mathematical formulas based on the number of each species vs the total number of species in an area.

The higher the number, the greater the evenness and the greater the biodiversity.

Biodiversity on different spatial scales

Biodiversity can be measured at different spatial scales.

Measuring biodiversity within a specific tract is called Alpha Diversity.

Comparing the number of common and differing species between two sites is called Beta Diversity.

Gamma Diversity measures the landscape or regional diversity, that is the diversity of habitats and species within a designated region. For example, a corridor under study may include both mountain and desert terrain as well as wetlands.

Why is biodiversity important?

Our existence depends on an earth having an abundance of biological diversity.

Biodiversity is necessary to support all living species and their health. We cannot obtain food sources without biodiversity. The oceans too must be home to a biodiversity of life if we hope to count on seafood to nourish us.

All the processes that support fresh air, rainfall, water cycles and the fertile soil needed to grow our food as well as the materials for shelter and clothing depend upon it.

It might be easiest to understand how interrelated life is by looking at a particular ecosystem. Fruit trees grow from fertile soil. Fertile soil is produced from branches and leaves which have fallen to the ground and rot into the earth. This process of decomposing is made possible by tiny microorganisms.

Insects, worms and grubs consume these tiny microorganisms.

The insects and worms are in turn food for rodents, small mammals and birds. Some of them may also be food for reptiles and larger animals.

For pollinators like bees and butterflies to exist here, the particular flowering bushes they feed on must be nearby. Bees and butterflies are crucial for pollination, which is essential for fruit to grow. Once the tree had borne fruit, birds and small mammals help ensure seed dispersal and that future trees will grow.

Biodiversity and important ecosystem services

A healthy forest or grassland can both provide oxygen and absorb carbon dioxide, a primary greenhouse gas contributing to global warming. Absorbing carbon dioxide is important because it helps to lower the greenhouse gas emissions and keeps earth’s temperatures moderate enough to sustain life as we know it.

This is a critical issue today because our fossil fuel use is adding exponentially to greenhouse gas emissions and our practice of deforestation is removing hope of containing it. It is a problem that feeds upon itself. Deforestation adds more carbon dioxide to the atmosphere, heating up the earth even more. The heat draws moisture from the ground, resulting in drier conditions which damage ecosystems that would help to remove carbon dioxide from the atmosphere.

Biodiversity in the ocean is also very important. Until recently, the ocean has been viewed as a great carbon sink for excess carbon and for providing oxygen. Phytoplankton, marine plantlike creatures, are widely considered to be at the bottom of the food web and the basis of life in the ocean.

Phytoplankton absorbs carbon. In fact, it presently absorbs between 30 to 50 percent of carbon produced by the burning of fossil fuels. And like plants and trees, phytoplankton provides oxygen. Scientists estimate that phytoplankton provides between 50 to 85 percent of earth’s oxygen [1].

The frightening news is that over 40 percent of phytoplankton has died since 1950 from warming oceans [2]. And the world’s greenhouse gas emissions are rapidly growing as more vehicles are driven, more household energy is demanded and more factories operate, providing a plethora of material commodities to consumers around the world.

Biodiversity is critical to water supply

The water cycle needs to function in a way that will allow water to evaporate into the atmosphere and then fall back to the earth as rain or snow.

This cycle depends upon moisture evaporating from trees and grasslands and from the oceans. When we lose these habitats, we lose their contribution of moisture.

The warmer air is causing the oceans to evaporate more rapidly. It is also pulling as much water as it can from already dry areas and makes its vegetation more flammable, which is why we are witnessing wildfires that are very difficult to contain. Additionally, snow on mountaintops is melting earlier and so many forests are dryer for longer periods of time.

Biodiversity stabilizes local climates

The loss of biodiversity is having a domino effect on weather events.

Another event only now being understood is the slowing of the ocean currents due to warming ocean water.

The ocean currents basically form a long conveyor belt around the globe. The currents dip down to the ocean floor where the water is cold and then rise as the water warms and becomes less dense, bringing up nourishing sediment from the floor to the surface of the ocean where there is an explosion of life, marine life and sea birds feasting on the nutrients. These currents have been fairly predictable.

For example, the Gulf Stream carries warm water and winds to a shore in Cornwall, England, that actually has palm trees. But now that the ocean has been warming it appears that this “conveyor belt” is slowing down and there are deep concerns that it may simply stop when the ice sheets have all melted, which is happening at an accelerated speed. This would result in changes of climate upon the Cornwall coastal area, making it cooler throughout the seasons.

Our weather patterns will shift as the currents do, causing extended droughts and more virulent storms. This can be very serious to many species, both plant and animal species who simply will not be able to adapt.

Food security and diversity of food crops  

As temperatures increase and weather patterns shift with global warming, the food crops we presently rely upon are at risk.

Current global population is seven and a half billion and expect to have nine billion people by 2050. With the advent of industrial agriculture, a world of monocultures of a handful of staple crops, we have lost much of the genetic diversity of crops.

With the present loss of biodiversity, our food supplies are more vulnerable to pests and disease. Without a diverse genetic pool of edible plants and food resources, our global food supply is weakened and may well be unable to provide food for us under differing conditions and extreme events.

Livelihoods and tourism

Biodiversity is critical to many local economies. The livelihoods of around 11 percent people in the world rely upon fisheries and aquaculture.

The tourism industry relies upon beautiful natural places like coral reefs, tropical rainforests, jungles. Focusing on growing and protecting biodiversity as a way of life is not only good for the economy, but in many places is essential for supporting local livelihoods.

Biodiversity hotspots – why are they so important?

A “biodiversity hotspot” is a place that is rich in plant and animal life and is in imminent danger of being lost.

Scientists define a biodiversity hotspot as an area with at least 1,500 vascular plans unique to the area and only 30 percent or less of its original vegetation remaining.

In short, these are areas with a rich variety of life that is vanishing fast. Species extinction is forever and the situation is even more dire than the definition suggests.

There are 36 hotspots generally recognized and of these, around 86 percent of their original habitat is gone. It is the original species which have evolved over thousands and millions of years that provide strength and resilience.

Once a large portion of an ecosystem is wiped out, it is no longer resilient. We need healthy ecosystems to supply oxygen, regulate climate change, and to provide clean water and fertile soil to grow our food and materials for shelter and clothing. Saving these biodiversity hotspots may be critical to our survival.

Medical and scientific benefits of biodiversity

The Amazon Rainforest has earned the name “Nature’s Pharmacy” because it has contributed the effective ingredients to 25 percent of the drugs used today in modern medicine. This figure is particularly astonishing given that only one percent of the Amazon plant species have been studied for medicinal benefits [3].

This is simply just one biome, albeit a rich one.

Every culture has its own native medicinal herbs. Plants do not grow in a vacuum. They need along with appropriate weather conditions the diversity of life to provide favorable soil conditions, protection from predators and disease, pollinators and animals or birds for seed dispersal. 

Biodiversity provides security against the ravages of infectious diseases within a population via a larger gene pool boosting resilience. It also provides a measure of safety against zoonotic diseases.

Biodiversity loss is a leading contributor to the blurring boundaries between animal and human pathogens. Enforcing illegal and exotic animal trade and simply allowing the rest of the natural world to have its space will help to insulate us from the rapid spread of zoonotic diseases we are witnessing today.

Even though we do not know the exact reasons, we should also not discount the well-known psychological experience of peace many of us feel in nature [4].

What are the major threats to biodiversity?

The biggest threat to biodiversity is habitat loss and land degradation caused in most cases directly or indirectly by our actions.

Big tracts of land have been destroyed by mining and are used as industrial waste sites. Lands have been deforested for timber and agricultural expansion. Habitats have been cleared for urban sprawl and for building more energy and manufacturing operations.

Well over 75 percent of earth’s land is substantially degraded [5]. Not good news for soil organisms, plants and all creatures relying upon them.

Good arable land has degraded to the point of becoming desert from unsustainable agricultural practices (e.g. overgrazing, over-tilling and poisoning with toxic herbicides) in many places on earth.

Pollution causes biodiversity loss in many places

We destroy habitats by polluting them. Our air, land and seas are all suffering from toxic levels of human pollution. This adversely affects living organisms dependent upon these environments.

Much of our water is polluted. Over 80 percent of India’s water is severely polluted [8]. Over 40 percent of lakes and rivers in the United States are too polluted to fish or swim in [9]. The biggest source of water pollution is from industrial and agricultural waste and inadequately treated human waste.

Each day two million tons of sewage and other effluents drain into the world’s waters, carrying debris.

The Great Pacific Garbage Patch is one of five offshore plastic accumulation zones in the world’s oceans and it alone covers an approximate surface area of 1.6 million square kilometers, an area three times the size of France.

Noise pollution too is threatening biodiversity. We are a noisy race with our machines and vehicles. The truth is that we simply don’t know the health impact on most species of our incessant noise. Many birds, fish and mammals fish rely upon sound waves to communicate, to sense predators, to determine direction and to find mates.

To this day, we do not know the extent of physiological injury that may be caused to underwater life by the sound of boat motors.

Far reaching effects of deforestation on biodiversity

Deforestation for timbering and agricultural expansion is the single biggest contributor to biodiversity loss and it shows no signs of stopping.

When an area is deforested, the animals who lived there or roamed through the area lose their habitats and feeding or mating grounds. If they are not killed outright which happens to all of the plant species and to animals, amphibians, reptiles and birds that cannot escape in time, then they must quickly find a place to relocate and adapt if possible.

Each particular instance of deforestation presents its own horrifying scenario. For example, the ongoing deforestation in Indonesia has orphaned countless young orangutans who need their mother’s nurturing for at least seven years to teach them survival skills. Many of these young have provided additional income for those destroying the forests who capture them until they can sell them through the exotic animal trade network where they are destined to live miserable lives under brutal conditions.

Orangutans share 97 percent of our DNA. They are intelligent and have feelings we can readily identify with.

Deforestation takes place all around the world, not just in the more highly publicized remote areas. It is taking place all around us and each time a swath of forest is felled, we lose biodiversity and make the neighboring remaining habitats more vulnerable to pests, diseases and ultimate extinction.

Invasive species reduce local biodiversity

Our global interconnectedness is promoting the spread of invasive species which then dominate and unbalance an ecosystem. Many of the problems we are experiencing from the spread of invasive species are the result of deliberate introduction of plant or exotic animal species to another environment through uneducated curiosity.

Other species have simply hijacked on carrier vessels, like the microbes that attach themselves to ship hulls and then devastate destination’s coastal marine ecosystems. Some even travel across species boundaries, possibly via consumption, to a new species that has no resistance and then spread across the globe… like the Corona Virus has, traveling within human bodies.

Even fishing and hunting can be a threat to biodiversity

We are overfishing our seas and overhunting our wildlife.

Overfishing is when vessels catch more fish than stocks can replenish. We have presently overfished more than one-third of our fisheries and while some conservation efforts are being made, it does not show signs of slowing.

If we continue at this rate, the world will run out of seafood in 2048 [11]. Not only have we overfished, but our barbaric fishing practices have swept up far more fish and marine life than used for consumption. Referred to as “bycatch” and trawling that is recklessly dragging huge heavy nets across the ocean floor. The consequences reach beyond the seas, extending to birds who rely on an abundance of fish as their food source.

We have driven nearly 52 percent of our wildlife species to extinction since 1980. In addition to deforestation, pollution and habitat loss, the illegal wildlife trade and hunting have played major roles.

Legal hunters kill tens of millions of animals per year and poachers hunting illegally have eliminated just as many [12]. Whether done legally or illegally, all types of hunting have led to extinction of species. If not controlled, many more animals will be doomed to extinction.

Climate change eradicates species

Greenhouse gas emissions have changed the chemistry, heat of the atmosphere and rainfall patterns within a span of one lifetime – far too short for adaptations to evolve.

This rapid climate change is threatening the lives of animals, fish and birds who live in or migrate to the arctic zones as the glaciers melt. It is adversely affecting the migratory and eating patterns of marine life as the oceans warm.

Climate change is in fact threatening all species which have evolved over millennia to thrive in a pre-industrial-age climate.

Biodiversity loss: what are the consequences?

Today we are witnessing a catastrophic decline in biodiversity. A loss of biodiversity causes numerous problems in different ecosystems. In fact, due to urban sprawl and deforestation, many species are rapidly becoming extinct.

The interconnectedness of the web of life touches at many intersections, depending upon the food sources and survival needs of each creature.

Let’s look at the patch of woodland where the soil is rich and fertile from microorganism feeding on decaying matter. The soil is fertile because microorganisms are decomposing fallen branches, leaves and debris. If the microorganisms are nonexistent, such as in the case in industrial agricultural farmland where herbicides have been sprayed, it would take far too long to decompose debris.

Assume too that there are no insects because there are no soil microorganisms for them to feed upon. With small insects gone, larger insects will not survive for the lack of food either.

Insects, worms and grubs provide food for small mammals and birds.

If there are no insects like butterflies, then the tree blossoms cannot be pollinated and will not bear fruit. Not only will the animals which depend upon the fruit for survival be at risk, but fruits carry the seed of the tree. But if there are no seeds, then new trees will not grow to replace dying ones.

The situation in the oceans is just as dire. We are facing a crisis of coral bleaching. We are losing coral reefs due to rising ocean temperatures and acidification, both consequences of global warming.

Up to 10 percent of coral reefs have been destroyed, and one third of the remainder face collapse over the next 10 to 20 years [13].

Coral reefs act as nurseries and provide marine sanctuaries. In fact, it is estimated that 25 percent of marine life, including over 4,000 species of fish depend upon coral reefs at some point in their lives [13].

We do not even know what the impact of losing the coral reefs will be. While some life may have a few alternative sources for food and shelter, some do not and will die.

In fact, according to the United Nations Convention on Biological Diversity, an estimated 34,000 plant and 5,200 animal species, including one in eight of the world’s bird species are facing extinction today. 30 percent of breeds of the main farm animal species are currently at high risk of extinction.

Yes, species have always been going extinct and new ones evolving. The concern is the recent dramatic increase in the rate of extinctions. Even a greater threat to biodiversity than the loss of individual species is the wholesale loss of ecosystems that sustain them.

If we lose ecosystems, we lose the processes that make Earth habitable: a temperate climate, oxygen, food, potable water and the ability to make clothing and provide shelter.

The loss of species affects whole ecosystems

The loss of a keystone species, one upon which an entire food chain depends in order to survive may well have consequences rippling far beyond the extinction of the less adaptive species.

The extinction of predators will cause an imbalance among their prey. A notorious example is when sea lions were hunted to extinction on the United States northwest coast of the Pacific Ocean.

Sea lions foraged for urchins which fed on the underwater kelp forests. The kelp forests supported a variety of life, ultimately benefiting not only fish, but birds and small mammals.

Without the sea lions, the population of urchins grew unchecked, they decimated the kelp forests and the entire ecosystem collapsed.

How can we protect biodiversity?

The solutions are within our reach and there are many opportunities for hands-on efforts. Good news is that we understand enough to take dramatic effective measures to protect biodiversity. We have the technology and the understanding.

Here are just a few suggestions how we can protect biodiversity:

Protecting oceans and stopping overfishing

We must stop overfishing and destruction of ocean habitats and marine populations by passing and enforcing regulations.

Presently only one percent of the oceans are protected from fishing [14]. The renowned naturalist David Attenborough predicts that we could save the coral reefs and mangroves with the life they sustain as important nurseries if we only protected one-third of our coastlines. Watch the video for more information.

We can designate times and routes for seafaring vessels that respect the migratory patterns of aquatic life.

Tackling the problem of overhunting and poaching

We have to stop overhunting and poaching by passing and enforcing regulations. One of the most effective ways to enforce regulations is to recruiting natives to the area where wildlife is being poached. They have the best knowledge.

Building sustainable economies around biodiversity hotspots which rely upon the integrity of the surrounding nature is an excellent way to protect them. Educating people to understand the significance of their environment is a critical step to effectuating the paradigm shift that will save us as a species and the wonderful diversity of life around us.

Even small steps such as understanding why it is important to stay on the paths in local and national parks instead of insisting on taking a selfie on a slippery hill of shale and destroying critical but tenuous wildflowers underfoot, can go a long way to preserving biodiversity.

Sustainable food production

We can change our agricultural and food consumption practices to waste less and to grow a variety of healthy food employing preindustrial methods that enrich the soil rather than destroying its life and inundating land, air, the food product itself and ultimately water with toxic chemicals.

On an individual level we can support local farmers’ markets to help small family farmers. Plant native grasses, flowers and shrubs to attract pollinators and build soil and habitats in backyards and urban green spaces.

Changing our daily lifestyle

We need to reduce greenhouse gas emissions by switching to green technology for our heating, electricity and transportation needs. We have to regulate the manufacture and use of plastic, single-use and non-biodegradable items. On an individual level, we should consume less.

The fashion industry has garnered negative attention in recent years over its water pollution and usage with the revelation that making a single t-shirt uses 2720 (!) liters of water [15]. Yet this does not appear to have altered mainstream buying patterns. If people were more mindful of the far-reaching consequences of their actions, would they change them?

Education is a first step. Making sure this is in a school’s curriculum would be civic-minded. Meanwhile, look to the origin of products when buying. The Forest Stewardship Council or Rainforest Alliance both certify products that do not contribute to habitat destruction and protect the human rights of indigenous people where they are grown.

The Marine Stewardship Council certifies seafood from sources committed to sustainable fishing.

Consider the cradle-to-grave impact of each product you buy. Current landfill technology is subpar and does not ultimately ensure the sanctity of our groundwater [16]. Too much waste still ends up in waterways and it could be the plastic bag or wrapping that you used that blew off the collection truck, which not only pollutes the water but also choked a fish or bird.

We can also turn to recyclable materials for building shelter rather than always relying upon timber.

What else can we do to help the biodiversity?

Start a seed saver exchange at the local library.

Contribute funding or time to conservation organizations already in existence.

Spearhead a project to create and preserve habitats in the local community. At the very minimum, take the equation to heart and be the change you wish to see.