Abiotic Factors of the Forest Ecosystem

An ecosystem is an extremely complex web of interactions between different species and the environment. In an ecosystem, such as a forest, this web of dependencies and relationships defines critical variables, including populations and habitats, for each species. Beyond predatory, symbiotic or parasitic relationships among species, however, an ecosystem is also shaped by abiotic -- non-living-- factors, such as the amount of sunlight, temperatures, atmospheric conditions, chemical elements and the presence of water.

Sunlight

• Particularly in a layered ecosystem like a forest, where tall trees shade the spaces underneath and particular habitats can exist at various levels in the canopy, the amount of sunlight is a critical factor in the ecosystem. Different plant species require different levels of sunlight to grow and thrive. Pines, for instance, require ample sunlight exposure to grow, while ferns and small palms thrive in the cooler understory beneath shading from taller trees. Similarly, cold-blooded animals like reptiles require several hours of sun exposure a day, while amphibians and mammals tend to concentrate in shaded areas; therefore, sunlight also determines the distribution of animal species.

Temperature

• Most organisms have a capacity to adapt to temperature changes within a certain range. Temperatures outside this range, however, can make an environment completely inhospitable to a particular species. Thus, the temperature of a particular ecosystem largely determines the kinds of animal and plant life that can exist within it. Dramatic changes in temperature often remove certain species from an ecosystem as increased heat or cold interferes with their life processes and replace them with other species better adapted to the new temperature ranges.

Atmospheric Conditions

• All life on Earth depends upon gas exchanges with the atmosphere, whether breathing oxygen or taking in carbon dioxide as plants do during photosynthesis. The composition and conditions of the atmosphere, therefore, play an important part in determining what forms of life can live and thrive in a specific ecosystem. In extreme cases, such as highland forests or forests in volcanic areas where the atmosphere has considerably less oxygen in it, the composition of the atmosphere determines what species of plants and animals can call the ecosystem home.

Chemical Elements

• The chemistry of an ecosystem, from the acidity of the soil to the kinds of chemicals that are dissolved in the air and water, also determines the kind of life-forms that can settle in the area. As an abiotic factor in a forest ecosystem, chemical elements can make the soil too acidic or basic for certain plants to take root or even make the water or air unsuitable for organisms not adapted to those specific conditions.

Water

• Perhaps most importantly, the presence of water is a determining abiotic factor in the composition of an ecosystem. The amount of precipitation, the presence of subterranean or surface water, the frequency of flooding and other hydrological elements can be the basis of ecosystem compositions. Just as some plants and animals are adapted to arid conditions, others require very humid conditions to complete their life processes. As a result, precipitation patterns and the amount of water in an ecosystem establish what organisms can take hold and reproduce in an ecosystem.