6.2 Biotic communities

Dr V Malathi

A collection of interacting living things of various species that live in the same region and depend on one another either directly or indirectly for survival is called a biotic community, or simply a community in ecology. All of the flora, fauna, fungus, bacteria, and other species that create intricate connections within an ecosystem are included in this community.

Main Aspects of Biotic Communities

Diversity of Species:Diversity of Species: The ecosystem’s total biodiversity is influenced by the various species that make up a biotic community. Depending on variables like climate, resource availability, and habitat stability, species richness can vary greatly. In general, communities with high species diversity are more resilient and stable.
Trophic Structure: The energy flow within biotic communities is represented by the trophic levels into which they are frequently organized. Important levels consist of:
- Producers: These are organismss that are at the base of the food chain and use photosynthesis to transform sunlight into energy, such as plants and algae.
- Consumers: These are herbivores, carnivores, and omnivores that get their energy from eating other living things.
- Decomposers: Microorganisms that break down dead matter, such fungi and bacteria, to replenish the soil with nutrients and finish the nutrient cycle.

“Trophic Web” by Thompsma Via creative commons and Wikimedia commons is licensed under CC BY 3.0

Species Interactions: Different interactions among species within a community influence survival and shape relationships. Among these exchanges are:

- Predation is the process by which one creature (the predator) hunts and devours another (the prey).
- Competition: When species vie for the same resources, such food, water, or territory, population expansion may be constrained.
- Mutualism: When bees pollinate flowers, both species gain from the relationship.
- Commensalism: Like barnacles on whales, one species gains an advantage without harming the other.
- Parasitism: When ticks feed on mammals, one creature gains an advantage at the expense of the other.

4. Niche Differentiation: Depending on its behavior, nutrition, and environmental needs, each species in a group fills a certain niche, or role. By using various resources or adjusting to diverse environments, niche differentiation helps lessen direct competition and permits many species to coexist.

5. Succession and Change: a process called ecological succession enables biotic communities change over time.

There are two types of succession: primary (beginning from scratch) and secondary (occurring after a disturbance in an established community). A more mature and stable community is the outcome of succession, which causes some species to be gradually replaced by others.

Importance of Biotic Communities

As biotic communities provide a variety of ecosystem services, including pollination, soil formation, nutrient cycling, and climate regulation, they are crucial to the stability and health of ecosystems. Through their intricate relationships, these communities sustain the life cycles of individual species, contribute to the preservation of genetic diversity, and guarantee the survival of ecosystems. They are essential for resilience and sustainability on a broader scale because they enable ecosystems to bounce back from shocks and adjust to shifting environmental conditions.

Major types of biotic communities

1. Forest Communities

Tropical Rainforest: High biodiversity, thick canopy layers, and year-round warmth and precipitation are characteristics of tropical rainforests. These forests are divided into different strata, or layers. The vegetation is organized into a vertical pattern from the top of the soil to the canopy. There are many different kinds of plants, insects, birds, mammals, and reptiles in tropical rainforests.
Temperate Forest: Found in areas with distinct seasons and a moderate climate, temperate forests are primarily made up of coniferous trees like pines and firs and deciduous trees that lose their leaves once a year. temperate forests are the major source of ecosystem services such as timber, biomass, carbon, soil fertility and regulating water, nitrogen, carbon cycles locally and globally
Boreal Forest (Taiga):The boreal forest or taiga exists as a nearly continuous belt of coniferous trees across North America and Eurasia. The taiga corresponds with regions of subarctic and cold continental climate. Boreal forests are home to a few tree species, primarily evergreens, and are home to animals that have adapted to the cold, such as bears, moose, and a variety of birds.

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2. Grassland Communities

Savannas: These are grasslands with sporadic trees. They are found in tropical and subtropical areas. They are home to huge herbivores like zebras and elephants as well as predators like lions and cheetahs.
Temperate Grasslands: These grass-dominated communities, which are referred to as steppes in Europe or prairies in North America, are home to small burrowing mammals as well as grazing species like antelope and bison.

3. Desert Communities

Hot Deserts: These dry areas with high temperatures and little precipitation are home to communities that have adapted to the tough environment. Common creatures include reptiles, tiny mammals (such as kangaroo rats), succulents, and cacti.
Cold Deserts: Located in arctic or high-altitude areas, cold deserts are characterized by a lack of vegetation, including grasses and bushes, and are home to hares, jackrabbits, and some birds.

4. Aquatic Communities

Freshwater Communities: These are found in rivers, lakes, ponds, and streams. They are home to a variety of fish, amphibians, and invertebrates as well as plant species like algae and aquatic plants.
Marine Communities: Consist of maritime areas with diverse ecosystems, such as deep-sea habitats, open oceans, and coral reefs. Fish, marine animals, mollusks, crabs, and coral are among the species that call these ecosystems home.

5. Tundra Communities

Tundra communities, which are found in high mountain ranges and polar regions, are characterized by permafrost, minimal biodiversity, and extreme cold. Small shrubs, lichens, and mosses make up the majority of the vegetation. Caribou, arctic foxes, polar bears, and migratory birds are among the common fauna.

6. Wetland Communities

Marshes and Swamps: Located in regions with stagnant or slowly flowing water, wetlands are home to a diverse range of flora and fauna, including fish, amphibians, waterfowl, insects, and reeds and water lilies.
Mangrove Forests: Found around tropical coasts, mangroves are salt-tolerant trees that provide as crucial coastal protection habitats for fish, crabs, birds, and other marine life.

7. Coral Reef Communities

One of the planet’s most varied ecosystems, coral reefs are located in the warm, shallow waters of tropical oceans. They are home to a variety of animals, such as fish, crabs, mollusks, corals, and sea turtles. For many marine species, coral reefs are also crucial nurseries.

8. Urban and Suburban Communities

Urban and suburban populations contain creatures that have evolved to living in human-dominated regions. Common species include insects, plants that have adapted to disturbed habitats, small animals like squirrels and raccoons, and birds like pigeons and sparrows.Every member of these biotic communities has a distinct function in the environment, promoting nutrient cycling, sustaining intricate food webs, and enhancing biodiversity. These communities’ unique environmental circumstances and ecological forces have a significant impact on the species composition, adaptations, and interactions among them.

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