Terrestrial ecosystems are land-based communities where living organisms interact with their physical surroundings. These systems, which range from expansive forests to arid deserts, include animals, plants, and microorganisms, all coexisting within specific natural areas. The unique characteristics of each terrestrial environment, such as temperature, humidity, and altitude, allow various species to thrive.
Characteristics and Fundamental Processes
Terrestrial ecosystems are shaped by the interplay of biotic, or living, and abiotic, or non-living, components. Biotic elements include all organisms from microscopic bacteria to large mammals, while abiotic factors encompass sunlight, water, soil composition, and temperature. These elements determine the type of ecosystem present.
Within these systems, energy flows primarily through photosynthesis, where plants convert sunlight into energy. This energy then moves through food webs, from producers (plants) to consumers (animals). Nutrients like carbon, nitrogen, and water cycle through the ecosystem. Decomposers, such as bacteria and fungi, break down dead organic matter, returning these nutrients to the soil for reuse by plants, sustaining the cycle.
Major Terrestrial Biomes
Major terrestrial biomes are defined by distinct climate patterns, dominant vegetation, and characteristic animal life. These environments include forests, grasslands, deserts, and tundras. Precipitation and temperature are the two most influential climatic variables determining the biome type.
Tropical rainforests, found near the equator, have consistently high temperatures and abundant rainfall. They support a high diversity of plant and animal species, featuring dense, multi-layered canopies. Temperate deciduous forests experience distinct seasons with moderate rainfall, dominated by broad-leaved trees like oak and maple. Boreal forests, also known as taiga, have long, cold winters and short summers, with coniferous trees such as spruce and fir.
Grasslands, including savannas and prairies, are dominated by grass species with few trees. Savannas are hot, tropical grasslands with scattered trees. Prairies, temperate grasslands, have hot summers and cold winters. Deserts are defined by extremely low rainfall, leading to sparse vegetation like cacti. Tundras are cold biomes located in Arctic and alpine regions, featuring extremely low temperatures and limited vegetation like mosses and lichens.
The Role of Terrestrial Ecosystems
Terrestrial ecosystems provide many contributions to the planet and life. They support vast biodiversity, providing habitats for most of Earth’s plant and animal species. These ecosystems are estimated to support over 80% of the world’s biodiversity, including numerous unique and threatened species.
They also regulate global climate patterns. Forests, for example, sequester carbon dioxide from the atmosphere through photosynthesis and produce oxygen, which helps regulate the climate. Terrestrial ecosystems also influence hydrological cycles, with forests intercepting precipitation, enhancing soil infiltration, and contributing to evapotranspiration, which affects cloud formation and local rainfall. This helps manage water distribution and prevent floods and droughts.
Beyond environmental regulation, these ecosystems provide resources. They are sources of timber, food, and medicinal plants, directly benefiting humans. Terrestrial ecosystems also contribute to water purification by filtering pollutants and stabilizing soil, maintaining water quality in rivers, lakes, and groundwater sources.