Sub tropical deserts

Ecology

1. GENERAL ECOLOGY SUB – TROPICAL DESERTS SUBMITTED to: MA’AM VENUS ROSE SORIANO

2. GROUP MEMEBERS (GROUP 3) DHAIRY SARDHARA. DIVYA REDDY Y. HARSH ANAND. CHITTA DHEERAJ. JANI SAHIL BHARATKUMAR. NINGAPPA GAGANA. SREE HARSHITHA PAGADIPALA.

3. CONTENTS INTRODUCTION. PHYSICAL CHARACTERISTICS. ABIOTIC CHARACTERISTICS. ADAPTATIONS IN SUB TROPICAL DESERTS. WORLDWIDE LOCATIONS: CONTINENTS HAVING SUB TROPICAL DESERTS. PLANT LIFE IN SUB TROPICAL DESERTS. ANIMAL LIFE IN SUB TROPICAL DESERTS. FOOD WEB IN SUBTROPICAL DESERTS.

4. INTRODUCTION TROPICAL DESERTS: Tropical deserts are in regions between 5- and 30-degrees latitude. Environment is very extreme. They have the highest average monthly temperature on Earth. Rainfall is sporadic; precipitation may not be observed at all in a few years. In addition to these extreme environmental and climate conditions, most tropical deserts are covered with sand and rocks, and thus too flat and lacking in vegetation to block out the wind.  Wind  may erode and transport sand, rocks and other materials; these are known as  eolian processes . Landforms caused by  wind erosion  vary greatly in characteristics and size. Representative landforms include  depressions  and  pans ,  Yardangs ,  inverted topography  and  ventifacts .

5. SUB – TROPICAL DESERTS: A subtropical desert is a type of ecosystem, or biome that is characterized by high temperatures, very low precipitation and warm soils. Examples of these types of deserts are the Mojave, Sonoran, Chihuahua, Sahara and the Great Victoria Deserts. Subtropical deserts, which exist between 15° and 30° north and south latitude, are centered on the Tropics of Cancer and Capricorn. In some years, evaporation exceeds precipitation in this very dry biome. Subtropical hot deserts may have daytime soil surface temperatures above 60°C (140°F) and nighttime temperatures approaching 0°C (32°F). In cold deserts, temperatures may be as high as 25°C (77°F) and may drop below -30°C (-22°F). Subtropical deserts are characterized by low annual precipitation of fewer than 30 cm (12 in), with little monthly variation and lack of predictability in rainfall. In some cases, the annual rainfall can be as low as 2 cm (0.8 in), such as in central Australia (“the Outback”) and northern Africa.

6. PHYSICAL CHARACTERISTICS Subtropical desert’s warm, with average annual temperatures above 10 C and precipitation up to 100 cm (about the length of a baseball bat) /year. Most of the Subtropical Deserts are located at 30ONorthor South latitude; this is where air that was warmed at the equator falls back to the ground as cool, dry air (losing its water as it rises wet and steamy over the equator). These dry winds dry the land except for areas which are wetted by onshore breezes from warm offshore waters, such as the Gulf coast of the United States or the eastern coast of Indochina. Due to high evaporation of water in deserts, clay soils form the driest habitats as water is kept close to the surface by capillary action and thus prone to evaporation. Sandy soils offer better water supplies, and rocky and fissured soils provide the wettest habitat. Some desert areas haven't received a single drop of rain in hundred of years!

7. The region is characterized by dry-desert vegetation, a class of xerophytic plants that are widely dispersed and provide negligible ground cover. In dry periods, visible vegetation is limited to small hard-leaved or spiny shrubs, cacti, or hard grasses. Many species of small annuals may be present, but they appear only after the rare but heavy rains have saturated the soil. There are relatively few large mammals in deserts because most are not capable of storing sufficient water and withstanding the heat. Deserts often provide little shelter from the sun for large animals. The dominant animals of warm deserts are nonmammalian vertebrates, such as reptiles. Mammals are usually small, like the kangaroo mice of North American deserts.

8. ABIOTIC CHARACTERISTICS Temperature Tropical deserts have the highest average daily temperature on the planet, as both the energy input during the day and the loss of heat at night are large. This phenomenon causes an extremely large daily temperature range. Specifically, temperatures in a low elevation inland desert can reach 40°C to 50°C during the day, and drop to approximately 5°C at night; the daily range is around 30 to 40°c There are some other reasons for significant changes in temperature in tropical deserts. For instance, a lack of water and vegetation on the ground can enhance the absorption of the heat due to  insolation . Subsiding air from dominant high pressure areas in a cloud-free sky can also lead to large amounts of insolation; a cloudless sky enables day temperature to escape rapidly at night .

9. Precipitatio n Precipitation is very irregular in tropical deserts. The average annual precipitation in low latitude deserts is less than 250 mm. Relative humidity is very low only 10% to 30% in interior locations. Some deserts do not have rainfall all year round, because they are located far from the ocean. High-pressure cells and high temperatures can also increase the level of aridity. Wind Wind greatly contributes to aridity in tropical deserts. If wind speed exceeds 80 km/h, it can generate  dust storms and  sandstorms  and erode the rocky surface. Therefore, wind plays an important role in shaping various landforms. This phenomenon is known as the eolian process. There are two types of eolian process:  deflation  and  abrasion .

10. First,  deflation  may cause the light lowering of ground surface, leading to deflation hollows,  plains ,  basins , blowouts, wind-eroded plains and parabolic dunes. Second, the eolian process leads to  abrasion , which forms special landforms with a significant undercut . Soil: The soil in Subtropical Deserts is either sandy or coarse and rocky. But either way it is very dry which makes supporting plant life very difficult.

11. Plants and animals in subtropical deserts must be able to withstand the hot temperatures and lack of moisture. Shrubs and small trees in the subtropical desert usually have leaves adapted to retain moisture. Animals in subtropical deserts are usually active at night, when it is cooler. ADAPTATIONS OF SUB TROPICAL DESERT

12. WORLDWIDE LOCATIONS: CONTINENTS HAVING SUB TROPICAL DESERTS. Asia Australia North America South America Africa

13. Locations of the five subtropical desert cities: Beer Sheva, Israel; Hotan, China; Jodhpur, India; Kharga, Egypt; Las Vegas, NV, USA. 

14. PLANT LIFE IN SUB - TROPICAL DESERTS The most common plants in sub tropical deserts are cacti, spiny, shrubs, hard grass species Plants in sub tropical deserts must be equipped to withstand the high temperatures and lack of moisture. Many of the shrubs usually have leaves which have adapted to lock in moisture.  

15. Desert environment is usually not best suited for subtropical plants -Subtropical plants grow well in fertile, decomposed ,deep loam soil. They will not survive in locations with poor drainage. -Xerophytes (dry loving plants) are common Creosote bush: Open scraggly shrub -Elephant trees: Stores water in spongy wood in trunk -Therophytes (annuals via seeds) Geophytes (survive under ground) -Cactus (commonly found in deserts) Desert annuals(The soil contains a "seedbank. “Many annual shave hard seed coats of variable thickness)

16. ANIMAL LIFE IN SUB – TROPICAL DESERTS Most animals who live in Subtropical Deserts are nocturnal. It is very hard to survive due to the arid conditions. Many of the animals are cold blooded. Many animals, such as camels, tortoises, birds, foxes, rodents and lizards, also live-in subtropical deserts. A prime example of a subtropical desert is the Grand Canyon region, the Mojave Desert or Sonoran Desert .

17. FENNEC FOXES : have thick fur on feet protecting them from the hot ground; have large, bat-like ears radiate body heat and help keep them cool; have long, thick hair that insulates them during cold nights and protects them from the hot sun during the day; have light coloured fur to reflect sunlight and keep their bodies cools.  SPOTTED HYENA : They are good swimmers and can walk under water! They can make over 10 different sounds, but the most sound is the laughing noise they make – therefore they are also called laughing hyenas. They eat animals like zebra and wild beasts. They can survive in various types of environment, including dry climates.

18. KANGAROO RAT getting moisture from their seed diet; living in burrows during the day to avoid extreme heat; having large back legs that allow them to jump almost 3m to avoid predators; having large ears, which enables them to hear approaching predators OSTRICHES: They may not be able to fly, but they are the largest and fastest running birds in the entire world! They will eat pretty much anything if they have to, but mostly plants, grass and seeds. They don’t drink very much that helps them survive in dry climates.

19. CAMELS have humps to store fat which a camel can break down into water and energy when food is not available; rarely sweat, even in hot temperatures. have large, tough lips enable them to pick at dry and thorny desert vegetation; have broad, flat, leathery feet to spread their weight and provide protection from hot sand.

20. FOOD WEB IN SUB - TROPICAL DESERTS A food web is the natural interconnection of food chains and a graphical representation of what-eats-what in an ecological community. In a food chain in our Sub tropical desert region – as in a food chain in any other biologically distinctive region, or “biome,” on earth – it is the plants, or the “producers,” that capture the energy from the sun and initiate the flow, becoming the first link in the chain. In an almost magical-seeming process called “photosynthesis,” which means “gathering of light,” all plants – from one-celled diatoms to mesquite and creosote shrubs to the towering saguaro cactus to riverside cottonwoods and willows – use the sun’s energy, with water and carbon dioxide, to produce a carbohydrate, or sugar, called “glucose,” a basic component in the food chain. The plants then use the glucose to produce the carbohydrates, proteins and fats required for reproduction and growth, drawing nourishment from various soil nutrients, for instance, nitrogen, phosphorus and potassium. As producers, the plants, in effect, create storehouses of solar energy, setting the dinner table, often impoverished in the desert, for the animals, the consumers

21. THANK YOU ENVIRONMENT IS NO ONE’S PROPERTY TO DESTROY; ITS EVERYONE’S RESPONSIBILITY TO PROTECT.