Community in biology is defined as the assembly of different organisms and their interactions. Organisms interact with one another through symbiotic relations, including mutualisms, parasitism, competition and commensalism. Ecosystem diversity consists of biotic and abiotic factors, while a community only deals with biotic or living factors. A community can also be defined as a subset of ecosystem diversity.
Ecosystem diversity
Biodiversity and geodiversity combine together to form an ecosystem diversity. Ecological diversity comprises terrestrial and aquatic ecosystems. Ecological diversity also describes the variation in the complexity of the biological community. A better example of ecological diversity is the variation present in deserts, wetlands, oceans and grasslands. It also includes a great deal of genetic diversity and species diversity. The diversity of an ecosystem depends on the physical characteristics of the surrounding environment. An ecosystem is also a community and is also a physical environment.
Ecosystem diversity describes the number of niches, trophic levels and various ecological processes that sustain energy flow, food webs and the recycling of nutrients. It has focused on various biotic interactions and the role and function of keystone species (species determining the ability of large numbers of other species to persist in the community).
There are three perspectives of diversity at the level of community-
Alpha diversity ( -index diversity, within-community diversity): It indicates diversity within the community. It refers to the diversity of organisms sharing the same community of habitat.
Beta diversity ( -index diversity, between-community diversity): It is the biodiversity which appears in a range of communities due to replacement of species with the changes in community/habitat due to presence of different microhabitats, niches and difference in environmental conditions.
Gamma diversity ( -index diversity): It refers to the diversity of the habitats over the total land scape or geographical area.
Community
The populations of naturally occurring species and occur in a particular environment
( geographical areas) are communities. For example, we can say that species that are found only in deserts and species found under the warm stone are communities. Some communities are large and more complex, so they cannot be clearly defined. And these include lowland fen communities of the British Isles, old-growth forests of the northwest coast of North America, etc.
We can also say that a community includes biotic things alone since it deals with living things only. Biologists often use the word community as a subset of organisms present in a large community.
Classification of community
Community is classified based on overall appearance or it can be called physiognomy. For instance, communities can be classified as coral reef communities and are based on the appearance of those reefs. Based on the physical characteristics of streams, stream communities are classified. In this way, riffle zone communities and pool communities are also present. And also another mode of classification is also present and is most frequently used. Such as Mediterranean scrubland communities, the Pacific Northwest region of the U.S, etc.
There are mainly two types of communities – major community and minor community. One that is self-regulating and able to sustain itself is a major community. Examples of major communities are forests, grasslands, lakes and ponds.
Communities that are neither individually sustaining nor self-regulating are minor communities. Examples of minor communities include a collection of organisms living in a piece of deadwood.
Factors affecting diversity
It is extremely complex to find the factors affecting the diversity of a community. Some environmental factors that determine community diversity are temperature, sunlight, availability of organic and inorganic nutrients, precipitation, etc.
Biodiversity loss is also present and is due to factors such as habitat loss, climate change arising due to global warming, excessive fishing and hunting. This overexploitation by humans and invasive species is responsible for biodiversity loss. And in all these factors, human beings play a significant role in this biodiversity loss.
Community and ecosystem diversity
The study of different ecosystems in a particular location and their overall effects on the environment and humans as a whole is ecosystem diversity. It also deals with both aquatic and terrestrial ecosystems. We can also say that ecosystems contain both biotic and abiotic things, but abiotic things are not present under the category of community. Some of the important examples of ecosystem diversity are tundras, grasslands, deserts, rainforest, marine and terrestrial ecosystems and are responsible for creating a well-balanced environment. The biological community is the interacting group of organisms present in a common location that is only biotic things or one that is derived from living things. An example of this is a forest inhabited by animals, bacteria and fungi.
Conclusion
Community and ecosystem diversity are two important and distinct topics of biology. The community is also called a subset of ecosystem diversity since a community is a part of the ecosystem diversity. All the living things present in a desert can be called a community.
Ecosystem diversity contains both the living and non-living things and the interactions present on them. And it also represents the variability present in a particular area and its interaction with various environmental fluctuations. Expanding population and development require more industrial area, extension of present towns and cities, more area for agriculture, new roads, canals, dams etc.All these activities will result in destruction of natural habitat or habitat loss. Destruction of habitat is the primary cause of extinction of species.