Species Diversity Definition, and it is Important to us

Have you ever wondered just how many species there are on Earth? We know Earth is filled with wonderful creatures but sometimes we wonder exactly how many different living things there are out there.

According to the new estimate given by scientists, there exist about 8.7 million different species on Earth. However, many scientists also know and believe that this number is neither the ultimate nor it is the most accurate because there are still many more species that’re unknown to man and science.

This number of different species was predicted in a 2011 study and as of 2019, we’ve only discovered and identified just about 1.8 million. In short, we’ve only discovered about one-fifth of the estimated number. This should give us an idea of just how many different forms of life there are on Earth.

What is Species Diversity

Species diversity refers to the various numbers of species that are present within a specific community. Species diversity includes taxonomy or animal classification, its species richness, and phylogenetic diversity.

Species are most diverse in tropical rainforests or along the Equator. The exact reason why this is so is yet to be determined factually, but many scientists believe it’s due to the more favorable conditions of the Equator. The humidity in regions along the Equator allows more species to thrive.

Tropical rainforests cover only about 7% of the land on Earth, but nearly 50% of all species on Earth live here.

For example, in the rainforests of Costa Rica alone, there are more than 600 species of birds, over 1,200 butterfly species, thousands of different species of orchids, and many species of monkeys. These different species describe the diversity of species in Costa Rican rainforests.

Now, imagine the sheer number of other species in the rainforests in other countries. This huge number of species diversity contributes to the balance of the world’s biodiversity and the survival of many other species on Earth.

As we have discussed the importance of biodiversity in earlier parts, species diversity is directly related to maintaining Earth’s biodiversity. Each species, no matter how small or insignificant it may seem, plays different roles in the ecosystem.

Having many different types of species doesn’t only provide humans with food. Species diversity also ensures the availability of clean water, fertile soils, breathable air, prevention of diseases, and climate stability.

Since each species work in many different ways to contribute to a healthy ecosystem, having flaws or a dwindle in species diversity can have serious repercussion to the environment.

The biosphere may not function as efficiently and it will take a longer time for natural processes to regulate itself to make the environment a livable condition for all life forms. Species diversity is not just a matter of encouraging more species to thrive and survive. It’s about the livelihood and survival of all living creatures and organisms on Earth.

Species richness

If species diversity is about the various types of species that exist in a particular community, species richness is about the number of each species living in said community. An area that’s rich in species means there’s a high number of animals of one species living in that location.

In other words, species richness refers to the number of individuals per species relative to the abundance of distribution evenness in an ecological community. For example, if there are 600 species of birds living in a certain rainforest and there 1,200 species of butterflies that live in the same rainforest, then the butterfly species is richer than the birds.

Compared to species diversity, species richness is simply about how many individuals that of the same species living in any given community.

There are various ways to observe the pattern of species richness. One way is to determine its geographic patterns. As we mentioned earlier, tropical rainforests are homes for many different types of species. Its humid condition makes an ideal condition for many forms of life to thrive.

To observe species richness, we consider one species in one rainforest in contrast to another rainforest that also has the same species.

For example, howler monkeys can be found in the rainforests of Brazil, northern Argentina, and Bolivia. But the number of howler monkeys in each rainforest differs and this describes their species richness in each rainforest.

Species richness is the most common metric used in ecology. It’s the yardstick by which we measure the health of our biodiversity. Species richness is important because it contributes to the stability of the ecosystem, which in turn helps to maintain biodiversity on Earth.

Not only that, but species richness is also a way to measure our ability and effort to conserve the natural world. Human activities harm many animals’ habitats. These activities decrease not only species richness, but also destroy species diversity.

To maintain Earth’s biodiversity, we need to ensure the continuation of species and encourage their richness.

Species richness vs species evenness

While species richness refers to the number of individuals in each species, species evenness refers to the ratio of each species to one another. It measures the relative abundance of the various species in an area which makes up the species richness in that location. Species evenness is considered high when all species in a population have the same rate of abundance.

To illustrate this, let’s use our rainforest example again. Let’s say in two different rainforests, there are 8 different species of animals living in each rainforest. Both of these rainforests can be classified as having species richness.

However, upon further evaluation, one rainforest has equal proportions of individuals in each 8 species. Whereas in the second rainforest, one species dominates over the other 7 species. The first rainforest is considered the one with higher species evenness.

Both species evenness and species richness are the two main components of species diversity.

Species diversity is important in any ecological community or environment. An ecosystem is classified as diverse if it has a community of 10 species with equal distribution instead of having 10 species but with 90% of the individuals are of the same species.

Even though we’re familiar with the concept of “survival of the fittest” in the animal kingdom, each species needs each other more than we realize. They depend on each other as well on what each other contributes to the ecosystem.

In turn, species diversity in a healthy ecosystem contributes to the Earth’s biodiversity, helping all other life forms thrive.

This article is part of our Biodiversity Series.


About the author

Susanne Ricee

Susanne Ricee is the Diversity and Inclusion Specialist and Researcher at Diversity for Social Impact. Sue brings over 15 years of HR and Diversity, Equity, Inclusion consultation experience.
Sue's previous experience includes Microsoft, Target, and Kraft. Sue is also the manager of Diversity Leadership Directory