Deserts ecosystem

Deserts ecosystem

1. 1 TOPIC: DESERT ECOSYSTEM Presented by: ADNAN KHAN C.No : 28 Presented to: Dr. Farah zaidi

2. Definition of desert ecology , ecosystem Desert ecology is the study of interactions between both biotic and abiotic components of desert environments. A desert ecosystem is defined by “interactions between organism populations, the climate in which they live, and any other non-living influences on the habitat”. Deserts are arid regions which are generally associated with warm temperatures, however cold deserts also exist. 2

3. C ontd … Deserts can be found on every continent, with the largest being located in Antarctica ( 5.5 million square miles ) , the Arctic, Northern Africa , and the Middle East . Among all the terrestrial ecosystems, deserts are very typical landforms due to their unique ecological conditions. Desert and near-desert areas cover nearly one-third of the land surface of the globe . Deserts alone covers about seventh of the land surface. 3

4. 4 ANTARCTICA DESERT North Africa desert

5. Contd … We normally call deserts as “sand seas or oceans of sands”. Most of the major desert areas like as the Sahara, the Arabian, the Kalahari, and the Deserts of Australia All lie between 10 and 30 degrees north or south of the equator. 5

6. 6 Sahara desert, Africa

7. Several things which make up a desert ecosystem are: Structure Characteristics Animals The ecosystem is dependent upon the type of desert; temperate deserts, also referred to as cold deserts, or hot or subtropical deserts. Hot deserts and cold deserts have different kinds of ecosystems. However, despite being very different, the two kinds of deserts have a few similarities. 7

8. Similarities of temperate & subtropical deserts: Both get fewer than 10 inches of rain annually. Dry air is found in both kinds of biomes. Both have harsh living conditions that impact people or animals living there. Plants have adapted to having less water and harsher temperatures. Animals have adapted to the conditions as far as energy, food consumption and when to get out and be active. 8

9. Biotic and Abiotic components: In general, deserts are made up of a number of abiotic components – including sand, the lack of moisture, and hot temperatures – basically anything that makes up an ecosystem that isn’t alive. However, there are also a number of biotic factors that affect deserts, which include living things, such as plants and animals. 9

10. Characteristics of Deserts Deserts are characterised by the following ecological factors: Sandy soils and a rocky substratum. Scanty rainfall and high evaporation. Hot and Cold weather. Prevailing Wind action. Poor Soil Moisture and water resources. 10

11. Geomorphology** of Deserts Deserts are created by changes in climate and accumulation of sands and other rocky wastes. Sand covers about 10 to 20 per cent of the deserts. The rest of the land consists mostly of gravels, boulders, mountains, and various types of soils 11 **the study of the physical features of the surface of the earth and their relation to its geological structures

12. Sand dunes & Soils in Deserts Dunes are large piles of wind-borne sands reaching a maximum height of 250 metres above the surface. Dunes show many shapes and patterns that change continually due to the highly active winds. Deserts are considered to be highly dynamic geomorphic features. Dunes are characterized by two-sided slopes one along the windward direction and the other along the leeward side. Soils in desert regions are generally fertile but lacks soil moisture to encourage plant growth 12

13. 13

14. Temperature in deserts Climatologically, deserts are the hottest places in the world because they absorb more heat from the Sun than any other land in humid climates. Deserts are mostly under arid to semi-arid climates. The temperature varies during day and nights. In summer, desert temperatures often reach upto 38 °C during the day. They drop upto 25 degrees Celsius or more at nights. During the winter, temperatures in the desert range from 10 to 21 °C. 14

15. Rainfall over Deserts 15

16. 16

17. Water availability in Deserts 17

18. Arroyos and oasis 18

19. Contd.. 19 Oasis is a wet and fertile zone in a desert with vegetation. Underground water comes nearer to the ground surface. Open wells and springs do exist in such spots. Water that occurs within an oasis has been drawn through groundwater base flow from distant catchments like mountains or hills. Some oases may be small and can support only a few people, but others are large enough to support millions of people.

20. Oasis 20

21. Types of deserts 21

22. Life forms of Plants 22

23. Fauna of deserts Animals have developed special body structure and ways of life. Centipedes, gerbils, kangaroo rats, snakes, and scorpions spend the day in burrows. They come out to search for food only when temperatures drop at night. Many insects, lizards, and tortoises can tolerate high desert temperatures and are active in the daytime. Many of them retreat underground or find the shade of a tree, during the hottest part of the day 23

24. Some snails, insects, frogs, lizards, mice, and ground squirrels aestivate in deserts, i.e they sleep through the summer. Elf owls, roadrunners, snakes, spiders, bees and butterflies are the other fauna of deserts. Many desert dwellers have light-coloured skin, which helps keep them cool by reflecting sunlight. Desert animals include many kinds of insects, spiders, reptiles, birds, and mammals. Deer, foxes, wolves, and other animals may visit a desert after a rainfall. 24

25. Larger desert animals try to remain in shady areas during the day. The evaporation of water from their bodies lowers their body temperature, but this water must be replaced. Such animals obtain water from the food they eat and from the few water holes that exist in a desert. “Ship of the Deserts” ie . The Camels: These are unique creatures which can not only survive, but also help the human beings across hot, dry deserts with little food or water. 25

26. There are two chief kinds of camels: the Arabian camel, also called dromedary, which has one hump, and the Bactrian camel, which has two humps. The camels that graze in the Sahara can go all winter without water and may refuse to drink if water is offered to them. But a large, thirsty camel can drink as much as 200 litres a day. This water is not stored in the camel's body but replaces water previously used up. 26

27. 27

28. Annual production of dry matter The primary production in deserts depend on; the little amount of available water and also the consumption strategy adopted by the plants. It is very low as 30-300 gm/ sq.m /year in arid zones, above the ground. Lowest production 2.6gm/ sq m/year in dune community in dry year observed. Highest production 816gm/ sq m/year observed in large arroyo in Chihuahuan Desert. Average production 180gm/ sq m/year. 28

29. Annual production of dry matter The herbivores have a pronounced impact on primary producers. The detrital food chain seems to be less important in the desert than any other ecosystems. Because of the limited production and decomposition, nutrients are limited in the deserts. 29

30. Productivity Walter in 1954 has measured the net productivity of a series of deserts and semi-arid communities. This has also shown that the overall limiting factor of deserts in productivity is the moisture. It has been found that he annual net productivity of true deserts is less than 2000 kg per hectare When this is overcome due to rain, then the soil becomes a limiting factor. 30

31. References DESERT ECOLOGY By Prof.A . Balasubramanian, Centre for Advanced Studies in Earth Science, University of Mysore, Mysore. https://www.researchgate.net/publication/314933544_DESERT_ECOLOGY Conserve Energy Future https://www.conserve-energy-future.com/desert-ecosystem.php Wikipeda www.Wikipedia.org 31

32. References JSTOR https://www.jstor.org/stable/1308782?seq=1#page_scan_tab_contents 32