What are Biomes?

Biomes

Biomes Definition

• Biomes are large-scale ecological communities that are characterised by their dominant vegetation, climate, and other abiotic factors that shape their biotic communities

• Biomes are classified into five major classes:
  

  • Aquatic

  • Forest

  • Grassland

  • Desert

  • Tundra

• These major classes can be divided into further categories, for example:
  

  • Aquatic biomes are water-based ecosystems that are divided into freshwater and marine ecosystems, including lakes, rivers, oceans, and coral reefs

  • Forest biomes are dominated by trees and are categorised into tropical rainforests, temperate deciduous forests, and boreal forests

  • Grassland biomes are characterised by grasses and herbaceous plants and are categorised into savannas and temperate grasslands

  • Desert biomes are characterised by low rainfall and are dominated by cacti and other drought-resistant plants - they can be further divided into subcategories such as hot deserts, cold deserts, coastal deserts, and semi-arid deserts

  • Tundra biomes are found in high latitudes and are characterised by low temperatures and permafrost - they can be further divided into subcategories such as arctic tundra and alpine tundra

Biomes of the world

• Each biome has characteristic limiting factors that affect productivity and biodiversity
  

  • For example, in the desert biome, water is the limiting factor for plant growth, while in the tundra biome, low temperatures and permafrost limit plant growth

Forest Biomes

Grassland Biomes

Desert Biomes

Tundra Biomes

The Distribution of Biomes

• Insolation, precipitation, and temperature are the main factors governing the distribution of biomes
  

  • Insolation refers to the amount of solar radiation that reaches the Earth's surface and affects temperature

  • Precipitation affects the availability of water, which is a key limiting factor for many biomes

  • Temperature determines the rate of photosynthesis and respiration in plants, as well as the metabolic rates of animals

• The combination of temperature and precipitation determines the distribution of biomes around the world

Precipitation and temperature are the two most important climatic variables that determine the type of biome in a particular location

Effect of Climate Change on Biomes

• Climate change is one of the greatest threats to biodiversity on Earth
  

• As the global climate changes, the distribution of biomes is shifting, leading to significant impacts on ecosystems and the services they provide
  

• Biomes are collections of ecosystems that share similar climatic conditions, such as temperature and precipitation
  

  • As these conditions change, the boundaries between biomes shift, causing changes in the plant and animal species that live there

• Biome shifts can occur in two ways:

  • Range shifts - when species move to new areas to find suitable conditions as their current habitats become less hospitable

  • Biome type changes - when a biome transitions to a different type, such as a forest becoming a savanna or a tundra becoming a forest

Photo by Peter Burdon on Unsplash 

A changing biome type in Namibia

• The distribution of biomes is primarily determined by temperature and precipitation

  • As global temperatures rise, the boundaries between biomes shift poleward or upward in elevation

• This means that the warmer biomes, such as tropical rainforests and savannas, are expanding, while the colder biomes, such as tundra and boreal forests, are contracting

• The impacts of biome shifts are significant and far-reaching:

  • As species move to new areas or experience changes in their habitats, they may face new competition, predation, or disease

  • This can lead to declines in population numbers and even extinction in some cases

  • Biome shifts can also have impacts on the vital services that ecosystems provide to living organisms, especially humans, such as water regulation, nutrient cycling, and carbon sequestration