In this lesson, you’ll learn about the biodiversity that makes up a desert ecosystem. You will discover what makes a desert a desert and study the different plant and animal life that inhabit both hot and cold deserts.
When you say the word ‘desert,’ typically the first thing that springs to mind is a hot, dry, sandy area, which is an accurate picture.
However, an interesting fact that you may not think about is that the southern polar region, Antarctica, is also considered to be a desert! For a habitat to be listed as a desert, it must receive very little precipitation (rainfall or snowfall) throughout the year. This means that the southern polar region is, by definition, a desert. Regardless of whether the temperature is extremely hot or extremely cold, there is very little biodiversity in the desert because it is a harsh climate.
Hot Desert Biodiversity
One of the best-known deserts in the world is located in the United States: the Mojave Desert. This area encompasses a large part of California, Nevada, Arizona and Utah. This desert receives less than 13 inches of rain each year, and summer temperatures can exceed 120;F! Winter temperatures can drop into the 20s. Given these conditions, the Mojave Desert is considered one of the harshest ecosystems on the planet, and this is reflected in its biodiversity, or the amount of animal and plant life in a particular habitat.
Plants that live in hot deserts must be specialized to deal with high temperatures and very little water. This typically means cacti. Cacti don’t have true leaves; rather, they have spines, which help protect them from being eaten. The chloroplasts, or specialized cells that perform photosynthesis (or derive energy from the sun) of cacti have been modified to store water.
Also, these plants have a shallow root system that can rapidly absorb water during the rare times of rain. You may also find shrubs and desert grasses that have adapted to high heat and little rain in hot deserts.The animals found in desert ecosystems are also highly specialized to this unique environment.
Animals that have evolved to live in the desert are called xerocoles. The main reasons these organisms can survive in the desert is because they don’t sweat and can retain water. Camels can survive in temperatures up to 120;F without breaking a sweat! However, these large mammals are a rarity. Most animals found in hot deserts are much smaller, such as rodents, rabbits and coyotes.
You’ll notice that these animals all have very large ears; this helps them evaporate off heat and keep them cool. You’ll also find numerous insects, mainly scorpions, ants and beetles, and reptiles, such as snakes, tortoise and lizards. Birds, such as the roadrunner and hawks, are also found in deserts.
Cold Desert Biodiversity
Like warm deserts, cold deserts also have very little precipitation each year.
The annual average snowfall in Antarctica is 6.5 inches a year. This continent is also quite large, and the temperature can vary between around 32;F in summer to almost -130;F in winter! Another factor that makes this climate unique is light. Unlike hot deserts, which have a typical light/dark cycle, Antarctica has 24 hours of daylight during the austral summer and complete darkness during the winter. This affects the biodiversity of its ecosystem even further.Plant life in Antarctica is virtually nonexistent.
Since plants must photosynthesize to live, the constant darkness of winter makes existing as a plant in this dry, cold habitat very difficult. Additionally, as the continent is surrounded by ocean, there is a lot of salt in the soil. Several species of moss, fungi and lichens, which are all known to tolerate extreme environments, are found in Antarctica.
The animal life of Antarctica is even less diverse. The majority of year-round inhabitants are comprised of penguins and seals. There are also several species of whales and birds, including orca, right whales and skua, that use the waters around Antarctica as part of their migratory routes. The majority of the biodiversity of Antarctica is found in the waters surrounding the continent.
There are numerous species of invertebrate, or animals without a backbone, and fish. Given the extremely cold temperature of the Southern Ocean (only 28;F – that’s below freezing!), the animals in the ocean grow very slowly but can get extremely large.
The word ‘desert‘ usually conjures images of a hot, dry environment. While the definition of a desert does have to do with the lack of precipitation (rain/snowfall), deserts can either be hot or cold. The biodiversity, or variety of life in the desert, is based upon organisms that are specially adapted to survive without a ready supply of water. Whether hot or cold, the biodiversity of the desert is very low. In a hot desert environment, plants consist primarily of cacti.
In a cold desert, mosses, lichens and fungi are found. There are more animal species in hot deserts versus the cold, but the most notable distinction is that mammals living in hot deserts, such as camels, don’t sweat! The majority of the biodiversity in Antarctica, a cold desert, is comprised of animals that live in the waters surrounding the continent.
After this lesson, you’ll have the ability to:
- Identify what constitutes a desert
- Describe the biodiversity in deserts
- Differentiate the biodiversity in hot deserts versus the biodiversity in cold deserts