The key difference between biodiversity and species richness is that biodiversity refers to the variety of life found in a specific place on Earth or the total variety of life on Earth while species richness refers to the number of different species represented in an ecological community, landscape or region.
Biodiversity and species richness are two different terms in ecology. They sound similar in meaning. In fact, the two terms are similar in one sense, but biodiversity means a lot more than just the number of species.
CONTENTS
1. Overview and Key Difference
2. What is Biodiversity
3. What is Species Richness
4. Similarities Between Biodiversity and Species Richness
5. Side by Side Comparison – Biodiversity vs Species Richness in Tabular Form
6. Summary
What is Biodiversity?
Biodiversity is the term that refers to the degree of variation of life forms at different levels such as species, ecosystem, biome, or the entire planet. If the number of species is high in a certain place, this means that there is a high level of biodiversity. That means; the number of species corresponds with the biodiversity of a certain place or an ecosystem. However, the variations within a particular species could also be considered as the index of biodiversity, which means the number of subspecies or individual variations accounts for biodiversity.
Figure 01: Biodiversity
When considering a large region such as country or an island, the number of different ecosystems is a great index of biodiversity of that region. However, biodiversity is not related to the land area of the place; it is the number of ecosystems or the number of species that are important in biodiversity. For example, Greenland is a large island, but its biodiversity is much lower compared to Sri Lanka, which is a tiny island. Thus, this example indicates another important aspect of biodiversity – biodiversity of tropical regions is higher compared to that of temperate regions. It is because most of the solar energy is trapped at the tropics by green plants via photosynthesis, and there are organisms to consume that as food. Rainforests and coral reefs are amongst ecosystems with the greatest biodiversity.
According to accurate estimations, only 1% of the total evolved species on Earth are living in the present day, and the rest 99% belong to the extinct species due to mass extinctions.
What is Species Richness?
Species richness refers to the number of different species present in a certain place of interest. Since species richness indicates a number, the value could be similar in two places with similar environmental conditions. However, species richness does not account the importance of charismatic or endemic species. It only indicates the number of species present, but it does not specify which species are present. Therefore, the application of species richness in the conservation of biodiversity is not a key component. In fact, species richness does not consider the variation of the density of certain species.
Figure 02: Species Richness
One main feature of species richness is that it treats all the species in equal respect, and it implies that all the species are common and widespread. Hence, species richness only provides an idea of taxonomical diversity. But, it does not act as a good parameter in measuring the ecological importance of species.
What are the Similarities Between Biodiversity and Species Richness?
- Biodiversity and species richness are two terms in Ecology.
- They are related to the species present in a particular region.
- Both measures are high when the number of species is high.
- However, species richness is a measure used to describe biodiversity.
What is the Difference Between Biodiversity and Species Richness?
Biodiversity refers to the variety of life found in a place on the earth while species richness refers to the number of different species present in an ecological community, landscape or region. So, this is the key difference between biodiversity and species richness. Biodiversity covers a broader field than species richness. Most importantly, biodiversity accounts the importance of certain species in terms of taxonomical, ecological, and economic values while species richness only accounts for the taxonomical diversity. Therefore, this is a significant difference between biodiversity and species richness.
Moreover, a further difference between biodiversity and species richness is that biodiversity applies to all biological variations from genetic levels through species, ecosystems, and the entire planet whereas species richness is only interested in the number of species. Furthermore, species richness only takes into account how many species are there whereas biodiversity takes into account who, what, when, how, and how many biological forms are there. Thus, this is another significant difference between biodiversity and species richness.
Below infographic summarizes the difference between biodiversity and species richness.
Summary – Biodiversity vs Species Richness
Biodiversity is the term that refers to the variety of life found in a place on Earth. There are two key components of biodiversity. They are species richness and evenness. Species richness measures the number of species present in a particular region while evenness measures the relative abundance of the different species making up the richness of an area. Thus, biodiversity does not just account the number of species; it also accounts who, what, when, how, and how many biological forms are there. Thus, this is the summary of the difference between biodiversity and species richness.
Reference:
1. Cleland, E. E. “Biodiversity and Ecosystem Stability.” Nature Education Knowledge, 2011, Available here.
2. Pimm, Stuart L. “Biodiversity.” Encyclopædia Britannica, Encyclopædia Britannica, Inc., 4 Jan. 2019, Available here.
Image Courtesy:
1. “695359” (CC0) via Pexels
2. “Predicted patterns of marine mammal species richness” By Selig, E.R., Turner, W.R., Troëng, S., Wallace, B.P., Halpern, B.S., Kaschner, K., Lascelles, B.G., Carpenter, K.E. and Mittermeier, R.A. – (CC BY-SA 4.0) via Commons Wikimedia