CLIMAX COMMUNITY: CHARACTERISTICS, TYPES, EXAMPLES - ENVIRONMENT - 2025

A climax community is one that is part of a climax ecosystem so it has greater stability. The climax ecosystems are those that achieve a balance for specific environmental conditions, by developing the maximum trophic complexity achievable under these conditions.

For example, in a climate with high rainfall and warm temperatures like the tropical one, the climax community is the rainforest. In temperate climate conditions with four defined seasons, flat-leaf forests (broadleaf angiosperms) develop.

Climax community. Source: Delorme at French Wikipedia / Public domain

However, in addition to the general climate as a determining factor, other factors come into play, such as the soil, which also influences the vegetation that is established. Thus, for example, in the plains of northern South America savannas are established due, among other things, to their sandy soils.

In any case, climax communities develop the greatest possible amount of food chains, biodiversity, biomass and stability, which the environmental conditions of the area allow.

The paradigm of a mature community or climax is the tropical rainforest of the Amazon, with its great biological diversity concentrating an enormous biomass. But in opposite conditions, with a deficit of water and poor soils, the mature community that is reached is that of the desert.

Climax Community Features

Sustainable stability and determining factors

The climax community is also called potential vegetation and refers to a community of plants, animals and other organisms that is stable and sustainable. This occurs because it makes optimal use of the climate and soil conditions of its environment.

In the process of ecological succession, the climax community represents the last stage when the maximum possible interrelationships between its members are established. This equilibrium point is determined by one or more factors or agents that define the extreme limit of the sequence.

Ecological succession. Source: Tomasz Kuran aka Meteor2017 / CC BY-SA (http://creativecommons.org/licenses/by-sa/3.0/)

Among these factors is in the first place the macroclimate or the general climate that corresponds to the geographical area. Likewise, the microclimate (climate of a small area), the soil and even human action influence.

In aquatic ecosystems other factors come into play such as water turbulence, salinity or the amount of dissolved oxygen.

Mature community

There is an ecological tendency for communities to vary, advancing towards greater maturity in terms of complexity when a greater number of trophic relationships are established. That is, biodiversity increases, more food chains are created, and the number of trophic levels increases (producers, primary consumers, secondary consumers, and so on).

Increase in primary and biomass production

In succession, biomass (cells and living tissues) progressively increases, which implies a greater number of living beings and of greater size. There is also an increase in primary production (more plants or other primary producers generating energy).

Primary production / total biomass ratio

In the mature or climax community there is a decrease in the ratio of primary production to total biomass. This means that biomass accumulates that does not intervene directly in primary production.

For example, when the ecological succession goes from grassland to forest, there is a large amount of biomass in the form of tree trunks that do not photosynthesize.

Nutrient storage

Another relevant characteristic of a climax or mature community is that it decreases the reserve of nutrients outside the organisms. For example, in the grassland stage the greatest amount of nutrients is in the soil and a lesser part in the grasses.

However, when the succession is transformed into a wooded community, the greater amount of nutrients is accumulated in the biomass and a smaller proportion in the soil.

Stability

Mature communities or climax communities develop a series of their own mechanisms that allow them to maintain a stable dynamic balance.

For example, a tropical rainforest has a decisive influence on its interior climate and even its surroundings. This makes mature communities more tolerant of environmental changes, as long as they are not drastic.

Types of climax community

In descriptive terms, there are three types of climax communities, differentiating what is expected in theoretical terms and what actually exists.

Ideal climax community

This is a theoretical community, that is, the most mature community possible given the weather conditions. This is based on the knowledge available so far on the ecology of the communities.

For example, given a tropical rainy climate, the most mature community that should theoretically be in the area is the tropical rain forest. This category also implies that no disturbance is acting in the area.

Potential climax community

This concept refers to the most mature community possible that should be established if any disturbance in a given area disappears. For example, if a crop is established in an area with a tropical rainy climate, by eliminating it the succession would lead to the appearance of a tropical rain forest

Real climax community

This is about the climax or mature community that actually exists in an area, regardless of what the theory says it should be present.

Monoclimax Model

The concept of the climax community and the climax ecosystem has varied over time. At first it was considered that for a given weather condition there was only one possible climax community.

This is known as the monoclimate model, that is, a single climax community for each type of climate. This model has the disadvantage of prioritizing the climate as a determinant of the limit of the possible biological community.

Mediterranean pasture. Source: No machine-readable author provided. Ardo Beltz assumed (based on copyright claims). / CC BY-SA (http://creativecommons.org/licenses/by-sa/3.0/)

From this point of view, when the expected climax community does not appear in an area with a certain climate, it is assumed that there is a disturbance. Therefore, concepts of non-climax community types known as pro-climaxes were proposed.

Proclimax communities are defined as those that almost reach the climax state, but do not correspond exactly to the potential climax community. This occurs due to the action of some disturbance that modifies the succession and prevents reaching the climax and four types are known:

Disclimax

It is a different type of community from the one that should exist according to the macroclimate of the area, due to the alteration caused by human action or domestic animals. For example, the Mediterranean pasture has a balance associated with the presence of pigs and cattle.

Pre-climax

A community type corresponding to a drier or colder climate than the climax community corresponding to the macroclimate of the area. For example, an area where it rains enough, but a rocky or sandy soil decreases water retention.

Post climax

A community with a climate that is more humid or warmer than the one in the area where it develops. It can be determined by the presence of an underground water reserve or a river in a dry area.

Sub climax

They are communities that precede the climax, appear to be climax (climax communities) but have not reached the potential climax. This is due to some persistent disturbing factor such as fire, waterlogging or other.

Polyclimax Model and Climax Pattern

Later other visions were raised, where it is considered that in a given region with a certain climate a mosaic of climax communities is actually presented. These respond not only to the general climate, but to other environmental factors such as soil variability and even microclimates.

In this sense, it is understood that the type of community of maximum biological complexity, that is, mature, does not depend exclusively on the climate. Therefore, the climax community responds to the combination of a number of factors, including climate, microclimate, soil, and even human action.

Examples

The Amazon rainforest

The tropical rainforest is the climax ecosystem par excellence and its best representative is the Amazon rainforest. Therefore, the communities that develop there, especially the non-floodable forest, constitute the greatest complexity of interactions achievable.

Amazon jungle. Source: lubasi / CC BY-SA (https://creativecommons.org/licenses/by-sa/2.0)

The Amazon rainforest as a climax community is the extreme point of a process of plant succession, as indicated by its biogeographic history. It is considered that in the first place communities of grasslands and forest patches were established that were changing to the current Amazon jungle.

Weather

As it is a region located in the equatorial zone, it receives high precipitation and high solar radiation uniformly distributed throughout the year. Temperatures are around 26 to 30 ºC average and rainfall exceeds 3,000 mm per year.

Floor

Originally it was a soil rich in minerals derived from the erosion of the Andes mountain range, which together with humidity and temperature allowed plant succession. In the process, the soils evolved to the current ones that are poor in nutrients.

Mature community or climax

Given these conditions, the Amazon rainforest has reached the maximum possible efficiency in the use of resources for biomass production. It is a community with high primary productivity, but with a greater accumulation of biomass (especially plant mass).

It generates its own internal climate and has a decisive influence on the global climate and also has a high biological diversity, which only in plant species reaches more than 40 thousand. On the other hand, there is a complex food web that involves thousands of species of all groups of living beings.

The Sonoran desert

It is located between the US and Mexico on the coasts of the Gulf of California, a temperate region with an extreme climate. Therefore, the potential climax community cannot be forested mainly due to the water deficit that limits the development of vegetation.

Weather

It is a hot and dry region, with temperatures above 38ºC in summer and up to 10ºC in winter. While the precipitation is less than 250 mm per year.

Floor

The soils are from the group of aridisols, with high sand content, very permeable and poor in nutrients.

Mature community or climax

Under these conditions, the dispersed grassland-shrubland is the climax community that can be reached in the ecological succession. Numerous species of succulent plants such as the Saguaro cactus (Carnegiea gigantea) are presented there.

Sonoran Desert. Source: Highqueue / Public domain

The Sonoran desert has low biomass and diversity compared to the Amazon rainforest, but these are the highest levels achievable given the climate and soil conditions.

References

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