Tropical Desert Biome

Sahara Desert

• Located in the northern part of Africa
• Rare vegetation, mostly sand dunes
• Very hot and dry, strong winds, sporadic rainfall
• Summer temperatures 136 degrees
• Winter temperatures below freezing in the north

Cacti

• African Peyote Cactus
• Thick stems and spiny leaves

Cacti can be considered a specialist species because it will die during winters at high latitudes or if it receives too much water. It has very specific living conditions which is why it is found mostly in deserts

Desert Mistletoe

An example of mutualism is between the desert mistletoe and phainopepla bird. The seeds of the desert mistletoe plant are covered in a sticky mucus so they do not fall to the ground. When these birds eat the berries of the mistletoe, they benefit from having a food source and the desert mistletoe benefits when the birds spread the seeds and help the plant reproduce

Sulcata Tortoise

(African Spurred Tortoise)

The keystone species is the sulcata tortoise because these tortoises dig sand burrows that other desert animals use for shelter and protection from the harsh weather of the Sahara desert

This is also an example of commensalism with other small desert animals because the animals benefit and it does not have a positive or negative impact on the tortoise

Jerboa

• Hopping desert rodents
• Run up to 24 km per hour

The jerboa has adaptations such as well-built hind legs made for digging and folds of skin that can close off its nostrils to sand

Sahara Sand Viper

• Camoflaged with sand
• Between 30 and 50 cm long
• Ambush from under sand or bushes

An example of predation involves the the sahara sand viper and the jerboa. The sahara sand viper hunts and eats the jerboa so it acts as a predator and the jerboa is its prey.

Fennec Fox

The fennec fox and the sahara sand viper both eat the jerboa, so they are in interspecific competition with each other over a common food source

The fennec fox can be considered a generalist species because of its ability to adapt to the harsh environment where it lives. They are omnivores who eat plants, animals, and basically anything they can get their paws on

Egyptian Tortoise

Egyptian tortoises live mainly in semi-desert biomes which is an example of a natural edge-effect and how biodiversity is higher in the area between biomes

The Egyptian tortoise is an endangered species due to habitat destruction caused by humans and intensive commercial collection. Agricultural expansion, overgrazing, cultivation, and urban encroachment have meant enormous pressure on this species' fragile and dwindling habitat, drastically reducing available vegetation for cover and food

Food Web

Limiting Factor: Water

The biggest limiting factor in this ecosystem is the availability of water. The desert is extremely hot and dry, so plants and animals have to adapt to store water and survive on small amounts of it. Most plants like the one shown have waxy leaves that help them retain water before it evaporates

Human Impact

Humans are destroying the desert habitat by over-hunting, collecting desert species, and creating man-mad edges. Global warming is also increasing the already hot temperatures of the desert which makes it hard for the animals to survive. When a species on the food web becomes endangered or extinct, the whole balance is thrown off and other species will see unhealthy increases and decreases in their population until the ecosystem is ultimately destroyed. For example, the fennec fox is endangered and less foxes means less sahara sand vipers get eaten. If the snake population increases, they could eat too many jerboas and cause that population to decrease and so on.

Fun Facts

• At 3.6 million square miles, the Sahara Desert is as big as China
• It is the world’s third largest desert
• It has been used as a set for Star Wars
• Dinosaur fossils have been found in the Sahara
• There are over 20 lakes in the Sahara