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Levels of Species Diversity

Grade 7
Jun 6, 2023


An Ecosystem with High Species Diversity

Tropical rainforests are a habitat for half of all species in the world. In the world, there are 5–10 million different types of bugs. The tropical regions are home to 40 percent of the world’s 2,75,000 blooming plant species. Tropical woods are home to 30% of the world’s bird species. Due to the relatively steady environmental conditions, tropical forests contain a high species richness.

Coral Reefs: Colonies of microscopic coral organisms make up the large coral reef environment. The transparency of the water in coral reef systems allows sunlight to penetrate deep into the coral, resulting in a high amount of photosynthesis in the algae that live within the coral. Species richness is the result of adaptation to varied disturbances and niche specialization.

Because it is warmer throughout the year, more biodiversity may be near the equator, allowing species to continue growing. Cold winters will inhibit the growth of microbes, plants, and animals in locations far from the equator.

Coral Reefs
Coral Reefs

Importance of Species Diversity

  • A diverse and balanced number of species exists in a healthy ecosystem to maintain the ecosystem’s balance. All species in an ecosystem depend on one another, directly or indirectly. It is crucial to maintain high species diversity to create a more effective, productive, and sustainable environment. Ecosystems with a greater diversity of species are more productive. For example, an ecosystem with many producer species will produce a large amount of biomass to support a larger number of consumer species.
  • An ecosystem with increased species diversity and production is more sustainable and stable.
  • The more diversified an ecosystem is, the better it can endure natural pressures such as drought or invasive infestations.
  • The diversity of species in an ecosystem allows it to respond to any disaster.
  • Each species in a species-rich community can use a different portion of the available resources depending on their needs. Plants with smaller roots, for example, can collect water and minerals from shallow soil, whereas plants with larger roots can dip into deeper soil.
  • For humanity’s survival, rich diversity is essential.
  • Nutrient storage and recycling, soil formation and erosion protection, absorption of hazardous gases, and climate stability are all benefits of rich diversity.
  • Nature provides many products to humans, including fruits, grains, meat, timber, fiber, raisins, colors, medication, antibiotics, etc.
  • Photosynthesis in the Amazon Forest is believed to produce 20% of total oxygen in the atmosphere. Pollinators, symbiotic interactions, and decomposers—each species plays a distinct and key role.
  • Large-scale interactions among species, such as those found in the food web, benefit from diversity.
  • Bacteria and plants have a critical relationship in the nitrogen cycle, and earthworms contribute to soil fertility.
  • There are also additional advantages, such as recreation and tourism, education, and research.



Types of Species Based on General Ecological Niche

In an ecosystem, each species serves a crucial role. The “ecological niche” is the role that a species plays in its ecosystem. An ecological niche is the totality of a species’ existence, including its capacity for reproduction, sustenance, and survival.

Types of Species

  • Generalist species
  • Specialist species
  • Native species
  • Non-native species
  • Indicator species
  • Keystone species
  • Foundation species

Generalist Species:

Generalist species occupy diverse ecological niches. These creatures may live in various environments and eat various foods, and they can adapt to changing environmental conditions and thrive. Cockroaches, rats, mice, flies, white-tailed deer, raccoons, humans, and other animals are examples.

white-tailed deer
white-tailed deer

Specialist Species:

They have a small niche, inhabiting only one type of environment and feeding on a limited range of foods. They are more sensitive to environmental changes and cannot adapt to changes and environmental stress.

Specialist species have an advantage in tropical rainforests, where environmental conditions are mostly consistent because they have less competition for resources.

Examples of specialist Species are: The giant panda of China, for example, is endangered due to its poor reproduction rate, habitat disruptions, and specialized bamboo diet.


Tiger salamanders reproduce in fishless ponds while crustacean-eating shorebirds prefer sandy beaches and adjacent coastal wetlands.

Giant panda of China
Giant panda of China

Native Species:

They are endemic or local species. Species known to live and thrive in a specific ecosystem are called native species. These species are only found in an area as a result of natural processes.

Kangaroos, for example, are endemic to Australia and found nowhere else in the world. Humans introduced them to their natural habitat in captivity, which is why they have been spotted outside of their normal habitat.


Native species might be either indigenous or endemic. When a species is native, it can only be found in a certain place and its surroundings. An indigenous species, for example, might be found throughout the Rocky Mountain range as well as the places west of the Rockies.

On the other hand, an endemic species is a native species found only in a small or big area. A species can be endemic to a whole continent or just a small portion of it. An endemic species, for example, may be found exclusively in a certain mountain range at a specific elevation zone and nowhere else or in a specific lake, a single river, or a small island. The Galapagos mockingbird is one of four native mockingbird species to the Galapagos Islands.

Galapagos mockingbird
Galapagos mockingbird

Non-native Species:

They are also called invasive or alien species. Species migrate to an ecosystem on purpose or by chance. If they locate a suitable niche, they can spread quickly. Invasive species compete for food and habitat with native species, and indigenous animals are forced to flee or die if unable to compete.

Example: Golden Apple snail was introduced purposefully in the Philippines for additional income for farmers.

Today the Golden kuhol is one of the perennial pests in our rice paddies.

perennial pests
perennial pests
Golden Apple snail
Golden Apple snail

Zebra mussels have become an invasive species in a number of countries throughout the world after being mistakenly introduced.

Indicator Species:

These species act as biological smoke detectors. These species provide early signals of environmental deterioration.

For example, the existence of trout species is a good indicator of water quality since they require clean water with high levels of dissolved oxygen to flourish, and birds are a good biological indicator of habitat loss and fragmentation as well as the usage of chemical pesticides. Butterflies are also good indicator species since they are vulnerable to habitat loss and fragmentation due to their relationship with numerous plant species. Coal miners employed canaries to detect dangerous and explosive gases in the mine.

Indicator Species
Indicator Species

Keystone Species:

In ecology, a keystone species is one that has a disproportionately great impact on the communities in which it lives. Such species contribute to the preservation of local biodiversity in a community by suppressing populations of other species that might otherwise dominate the community or by supplying important resources for a diverse range of species.

They perform roles such as controlling the population of other species by eating sick and old members.

For example, the starfish Pisaster ochraceous is an important species in rocky marine intertidal communities off North America’s northwest coast. This predatory starfish eats the mussel and is responsible for preserving much of the local biodiversity in particular communities.

When the starfish were removed in an experiment, the mussel populations expanded and completely covered the rocky intertidal shoreline, preventing other species from establishing themselves.

Keystone Species
Keystone Species

Figs and a few other plants act as keystone species in some tropical American forest communities, although in a fundamentally different way than the starfish Pisaster. These plants are important food sources. In some of these forest ecosystems, figs grow fruit all year, and a huge number of birds and mammals rely largely on this small group of plant species when other food sources are low. Many species would become extinct if figs were not present. They play a crucial role in preserving an ecosystem’s species variety and integrity. They have a significant impact on the species types and abundance in an environment. These species serve a number of important functions in ensuring the survival of certain species (e.g., pollination by bees and butterflies) as well as preventing the overpopulation of other species from becoming dominant. (e.g., top predators such as a wolf, lion, shark, etc.) For instance, removing predatory starfish from an ecosystem caused distinct species of mussels to outcompete other species, diminishing species diversity.

Foundation Species:

They are crucial in the creation and maintenance of habitats. Elephants, for example, in Africa’s grasslands and woods, push over or uproot trees to create an open forest, fostering the growth of grass and other vegetation needed by small grazing species like antelopes.

Foundation species are referred to as “ecosystem engineers” by biologists. Foundation species alter the environment physically and maintain habitats that benefit other organisms that use those habitats. Corals, for example, create coral reefs that are used by a variety of other species.

Create coral reefs
Create coral reefs

Kelp is another organism that might be regarded as a foundation species since it provides shelter and suitable habitat for a variety of other animals in marine environments. Brown macroalgae are responsible for the formation of kelp forests.

Levels of Species Diversity

In a landscape, species diversity can be observed at three different scales: Alpha diversity, beta diversity, and gamma diversity.

Alpha Diversity

Alpha diversity refers to the diversity of species within a community on a tiny or local scale, usually the size of a single ecosystem.

The total number of distinct species (also known as species richness) in a specific location is commonly used to represent it. As a result, alpha diversity provides us with species richness in that environment.

Alpha diversity
Alpha diversity

In comparison to beta and gamma diversity, it is a small-scale metric. When comparing species diversity among different ecosystems, species richness is a useful metric. A transect drawn throughout the ecosystem can be used to determine species richness. Species seen along the transect are counted, and the total number of species is recorded.

Beta Diversity

The term “beta diversity” refers to the variation in species variety between groups or ecosystems. As a result, beta diversity permits ecosystems to be compared in terms of biodiversity. The number of species that are unique to each system is recorded in beta diversity.

Beta diversity
Beta Diversity

When there is little interaction between adjacent groups, beta diversity increases. One of the key factors preventing species translocation between ecosystems is human land use. The free movement of animals between communities can be used to regulate beta diversity.

Gamma Diversity

Gamma diversity is a measure of a big geographic region’s overall biodiversity. As a result, it analyzes the total diversity of each ecosystem in the area.

Total diversity is determined by two factors: average species diversity in an ecosystem and species diversity differentiation among habitats. Gamma diversity is a type of species diversity found on a large geographic scale.

Gamma diversity
Gamma Diversity

Gamma diversity is a relatively large-scale measure compared to alpha and beta diversity. In today’s environment, we can see a decrease in gamma diversity all over the place. One of the main causes of decreased gamma diversity is mass extinction in many regions of the world.

Level of Species Diversity by Showing an Example

Let’s look at an example to better understand these three points of view. Assume the landscape is a mountainous area. The mountain slope usually has a mix of grasslands and forests, as seen in the diagram below.

The diversity of species present inside each grassland or forest patch on the slope is referred to as alpha diversity. Beta diversity refers to all species variety found between any two patches and their linked communities. Finally, the gamma diversity of a landscape refers to the diversity of all species present, as well as the slope’s entire range.

Levels of Species Diversity


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