What environmental conditions are favorable for lichens?

Lichens and favorable environmental conditions

In ecosystems there are numerous relationships between plants and animals. There are also interactions between themselves, with bacteria, fungi and other living things. Everything is related through a complex balance. Lichens also need these relationships in order to live. In fact, lichens are organisms that are the result of the symbiosis between a fungus and an alga.

What conditions are most favorable for lichens to develop well?

Lichens and the environment

lichens can grow on trees

Lichens in nature live in symbiosis with other species and are conditioned by the ecological factors of the environment that surrounds them. Its growth and metabolism are slow and are conditioned by the climate and the substrate where they are found. These ecological factors are conditioning factors during the life of the lichen and, in addition, they are the ones that mark the compatibility that exists between the components of the symbiosis.

The affinity that some lichens have for the accumulation of certain minerals that they extract from rocks or soil is known. This can serve as a bioindicator of soils with certain mineralogical deposits.

As I have commented before, they are the ecological factors which condition the situation and life of lichens. The relationship between flora and lichen vegetation varies depending on the geographical situation in which they are found, the climate, the characteristics of the substrate or the influence that other living beings exert on them.

Abiotic factors that condition the life of lichens

lichens grow on rocks

Abiotic factors are those who have no life and that are conditioning factors in the development of lichens, that is, factors such as soil, bedrock, climate, slope, etc.

the substrate

The first abiotic factor that conditions the life of lichens is the substrate where they develop. Lichens are capable of developing on all types of substrates such as minerals, bark, dead wood, leaves … and even on inert substrates like plastic.

The texture of the substrate is also considered a conditioning factor in the formation and development of lichens, since they depend on whether the crusts are thin, soft, hard, smooth, have cracks where moisture is more concentrated, etc. If it is rocks, it must be taken into account if they are hard, porous … or the soils if they are sandy, clayey, hard, stable, etc.

These factors condition the development of lichens as they will allow easier installation or they will retain water for a longer or shorter time.

Chemical composition and pH

The chemical composition of the substrate is, in many cases, the fundamental cause why certain species of lichens may or may not be found on substrates that have a similar physical nature. For example, siliceous soils host very different flora than soils that are rich in carbonates and gypsum.

On the other hand, the pH is an aspect to consider, since, depending on the acidity of the substrate, they will or will not influence the lichens.

The climate

Climate is one of the factors that most influences the development of lichens. For example, insolation, temperatures, rainfall regime they are conditioning factors in the responses of plants and communities that live in a territory, but even more so in the case of lichens.

Water and temperature

Water is also a limiting factor for the distribution of lichens. Water interacts directly on the vital functions of lichens. Depending on the water and humidity of the environment and the substrate where it grows, it may grow better or worse.

Temperature is a major determining factor in the distribution of lichens, as it has a decisive influence on metabolism. High mountain species have very different tolerance ranges from those in hot deserts. But this factor also acts indirectly on the availability of water, the higher the temperature of the surrounding air or that of the substrate, the faster the loss of water from the lichens.

Wind

Wind is an abiotic variable that has indirect effects on lichens. For example, in places where the wind regime is stronger, it acts on hydration status lichens due to the erosive and mechanical effect of the high speed wind.

Biotic factors that condition the life of lichens

biotic factors influencing lichens

We have seen that abiotic factors are closely related to lichens and condition their survival in the environment. However, in the ecosystems where lichens develop also live other living beings such as they are vegetables, animals and even man, that undoubtedly have an influence on the same habitats and modify their physical-chemical conditions.

The presence of other lichen species that will coexist among the same community, causes a competition for space and resources. Those species that have adaptations in their form or in their physiology that are more adequate to survive in environmental conditions, will have a greater capacity to colonize. In addition, it must be taken into account that those lichens that have higher tolerance ranges for some factors, can survive better.

A forest that produces shade and litter are negative factors for lichens. That is why lichens are more abundant and with a greater number of species in places where vegetation stages regress. These conditions cause more favorable spaces for its installation and development. As lichens are primitive organisms, they have little capacity for competition and will only dominate in those habitats where that of other plants is very small.

Lichens, due to their slow development, normally they cannot survive on moving or changing substrates, as is the case with many sandy rocks and some soils. For this reason, in sandy or gravelly areas they rest on dead vegetation, mainly stumps, decomposing plant material or mosses. Earth lichens can only colonize loose sand or rocks thanks to certain microorganisms and mosses that help compact the soil.

What activities affect lichens?

Lichens they are primary producers and some animals include them in their diet. Many of these animals generate a dependence on lichens for their food, as is the case of some insects, mites and mammals such as sheep and goats that depend on them for their winter diet in the taigas and tundras.

Grazing is an activity that negatively affects lichens. They create and favor the development of perennial grass, that are displacing lichen populations or leaving them highly fragmented. However, it is the human being who, through his activities, drastically affects lichens and has put some species, each day with smaller distribution areas, in real danger of extinction.

The global change in atmospheric conditions and the contamination of the troposphere by the discharge of gases and solid particles from urban and industrial centers, exerts a serious harmful influence on lichens long before other living beings show symptoms of having been affected. Massive and indiscriminate logging, arson, quarries, open-pit mining, etc. They are other aspects included in current anthropic activity and through which numerous habitats favorable to the normal development of lichens are being destroyed.

What environmental conditions are favorable for lichens?

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