Why Is Species Diversity Essential for Biodiversity and Ecosystems?
It is defined as the number of species and population of species that live in that particular environment. The population of species of that particular location is called species richness. There are approximately 1.8 million different species classified on Earth. Of all the total species, about one million belong to insects. New species are being discovered each year. Scientists estimate that there may be between 5 to 30 million species that actually live on Earth. Due to this wide diversity, there are different species diversity in different locations as different species are present in different locations depending upon their ability to adapt in that particular environment.
There Are Two Different Terms Regarding Species Diversity
Species Richness: The number of different species present in an ecosystem. Different areas have different populations as per their adaptive capability. Tropical areas have greater species richness as the environment is suitable and adaptable for a large number of species.
Species Evenness: Relative abundance of individuals of each of those species. If the number of a particular species is constant across the communities then they are called to have a high evenness and if the number of individuals varies from species to species, it is said to have low evenness. High evenness always leads to greater species diversity.
With the change in adaptive ability and geographical distribution, there are two types of species diversity, they are
The geographical location where there is high species richness but low species evenness.
Another is a geographical location where there is high species evenness and low species richness.
Importance of Species Diversity
There are so many positive reasons behind species diversity. Each species has a crucial role in ecosystem management. Example: Saprophytes act as decomposers, imagine if these saprophytes are not present in the ecosystem there will be no composting which will lead to several environmental problems like disruption of various ecosystem chains.
Some of the major importance are listed below:
Various species are helpful in the purification of water, purification of air, enhanced fertility of soils, maintaining climatic stability, and various other environmental factors.
It contributes to a healthy ecosystem. As each species has a specific link with a wealthy ecosystem.
More the species more will be the productivity in the ecosystem which will form a stable ecosystem.
The specific reason will be the ability to fight against any disaster.
More the diversity among species, the more will be their ability to respond against natural disasters like drought.
Because of high species, diversity people get various products like fruits, cereals, meat, wood, fiber, etc.
The Amazon forest contributes approximately 20 percent of the total oxygen in the earth’s atmosphere.
They maintain the soil fertility of ecosystems.
Pollination, symbiotic relationship, decomposition play a very unique role in the ecosystem.
Good biodiversity is necessary for the survival of mankind.
Apart from these, there are other benefits such as recreation and tourism, education, and research.
They are also prime destinations for tourists.
Threats to Species Diversity
Today's ecosystem is witnessing a large number of extinction of species due to several human activities which are harming our ecosystem. There are four main causes for the loss of diversity called the Evil Quartet. These are loss of habitat and fragmentation, invasion of any alien species, overexploitation, co-extinctions.
Overexploitation: Over harming or exploiting natural resources leads to the extinction of many species of biodiversity. Example: Many marine fishes are overharvested which leads to their extinction.
Loss of Habitat: Due to industrialization, urbanization various species lost their shelter and food which ultimately leads to the extinction of various species.
Example: the Amazon rainforest which is also called the lungs of Earth and house many millions of species are being cut down and cleared for different purposes. Likewise, tropical rainforest that once covered 14% of the land is not more than 6% left currently.Introduction of New Species: When new species are being introduced they start harming previous species which causes their extinction.
Example: Introduction of catfish in water reservoirs leads to the extinction of various existing species.Co-extinction: When species are interdependent on each other, extinction of one species leads to the extinction of another also.
Example: when a host fish is extinct parasites that are dependent on them also get extinct. Likewise, species that are involved in mutualistic relationships such as plant pollinators where if one species becomes extinct the other species becomes extinct too.
Steps Taken for Conservation of Biodiversity
There are several steps that are taken by the government to conserve biodiversity as they are getting depleted day by day. Some of the major steps taken by the government are listed below.
Rich biodiversity areas are protected as biosphere reserves, national parks, and sanctuaries, and this type of conservation is called in-situ conservation. In this type of conservation, various endangered species are protected from getting extinct in their natural habitat. Example: Royal Bengal tiger is native to the Indian subcontinent and is mainly conserved in National parks and Biosphere reserves.
Hotspot biodiversity areas are rich in species population. These areas are mainly determined on the basis of endemism, a threat to habitat, species diversity, and degree of exploitation. All over the world, there are a total of 34 hotspots. Example: Western ghat and Eastern Himalayas are two biodiversity hotspots of India.
India has various celebrations on protecting and planting trees. One of the famous among them is the Chipko movement.
In various lab and research areas, gametes of threatened species are preserved by cryopreservation techniques.
Ex-situ conservation is the type of conservation in which endangered species are given full protection and care for their conservation outside their natural habitat.
FAQs on Species Diversity Explained: Importance, Threats & Solutions
1. What is meant by species diversity as per the CBSE Class 12 Biology syllabus?
Species diversity refers to the variety of different species present in a specific ecosystem and the relative abundance of individuals within each of those species. It is a key component of biodiversity and is measured by two main factors: species richness (the number of different species) and species evenness (the proportion of each species).
2. What is the difference between species richness and species evenness?
Species richness and species evenness are two critical components used to measure species diversity:
- Species Richness: This is simply the count of the number of different species in a particular area. For example, a forest with 100 different bird species has higher species richness than a forest with 50 bird species.
- Species Evenness: This measures the relative abundance of individuals of each species. An ecosystem has high evenness if all species are represented by a similar number of individuals, leading to greater stability. Low evenness occurs when one or a few species dominate in population size.
3. What are the four major causes of biodiversity loss, commonly known as 'The Evil Quartet'?
The 'Evil Quartet' refers to the four primary threats that accelerate the extinction of species and loss of biodiversity. These are:
- Habitat Loss and Fragmentation: This is the most significant cause, where natural habitats are destroyed or broken into small, isolated patches due to deforestation, urbanisation, and agriculture.
- Over-exploitation: This involves harvesting species from the wild at rates faster than their populations can recover. Over-fishing, over-hunting, and illegal trade have driven many species like the Stellar's sea cow and passenger pigeon to extinction.
- Alien Species Invasions: When non-native species are introduced into an ecosystem, they can outcompete native species for resources, leading to their decline. The introduction of the Nile Perch in Lake Victoria is a classic example.
- Co-extinctions: This occurs when the extinction of one species leads to the extinction of another species that was dependent on it, such as in a host-parasite or a specific plant-pollinator relationship.
4. How is species diversity different from genetic and ecosystem diversity?
Biodiversity is studied at three levels:
- Genetic Diversity: This refers to the variation of genes within a single species. For example, different breeds of dogs or different varieties of rice show high genetic diversity.
- Species Diversity: This is the variety of different species within a region, as explained earlier. For instance, the Western Ghats have a much higher amphibian species diversity than the plains.
- Ecosystem Diversity: This is the variety of different ecosystems in a geographical area, such as deserts, rainforests, coral reefs, and grasslands, each with its own unique community of species.
5. What are some examples of biodiversity hotspots located in India?
A biodiversity hotspot is a biogeographic region with significant levels of biodiversity that is under threat from humans. To qualify, a region must contain at least 1,500 species of vascular plants as endemics. India is home to four major biodiversity hotspots: The Himalayas, The Western Ghats, the Indo-Burma region, and Sundaland.
6. Why is high species diversity considered crucial for maintaining a stable ecosystem?
A high level of species diversity is crucial for ecosystem stability because it enhances productivity and resilience. An ecosystem with many species has more complex food webs and is less likely to collapse if one species is lost. It can better withstand and recover from environmental stresses like drought, disease, or climate change because different species can fulfil similar roles, ensuring the ecosystem continues to function.
7. Explain the core difference between in-situ and ex-situ conservation methods, providing an example for each.
The primary difference lies in the location of conservation:
- In-situ (On-site) Conservation: This method involves protecting endangered species in their natural habitat. It allows the entire ecosystem to be preserved, enabling the species to evolve and adapt. Examples include National Parks, Wildlife Sanctuaries, and Biosphere Reserves.
- Ex-situ (Off-site) Conservation: This method involves conserving threatened plants and animals outside their natural habitats. This is done when their natural habitat is no longer safe. Examples include Zoological Parks, Botanical Gardens, and Cryopreservation (storing gametes at very low temperatures in gene banks).
8. How can an ecosystem have high species richness but be considered to have low overall species diversity?
This is a common misconception. An ecosystem can have high species richness (many different species) but low overall diversity if it has very low species evenness. This happens when a few species are extremely dominant in number, while other species are very rare. For instance, a forest might have 100 different tree species (high richness), but if 95% of the individual trees belong to just one species, the ecosystem is not considered highly diverse because it lacks balance and evenness.
9. Beyond providing tangible products like wood and food, what are the key ecosystem services that high species diversity offers?
High species diversity provides critical ecosystem services that are essential for human survival, often called the 'broadly utilitarian' argument. These include:
- Pollination: Bees, butterflies, and other insects ensure the pollination of a vast number of crops.
- Climate Regulation: Forests, like the Amazon, play a vital role in regulating global climate and producing a significant portion of the Earth's oxygen.
- Nutrient Cycling and Waste Decomposition: Microorganisms and decomposers break down organic matter, recycling essential nutrients and maintaining soil fertility.
- Purification of Air and Water: Healthy ecosystems with diverse vegetation and microbes help filter pollutants from the air and water.
