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California Deserts

California Deserts. California Deserts. Deserts. Defined as a region that receives less than 10” of ppt a year Irregular Temperature extremes Windy Nutrient poor alkali soils Low rates of primary productivity High rates of evapotranspiration. Low Irregular Precipitation.

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California Deserts

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  1. California Deserts

  2. California Deserts

  3. Deserts • Defined as a region that receives less than 10” of ppt a year • Irregular • Temperature extremes • Windy • Nutrient poor alkali soils • Low rates of primary productivity • High rates of evapotranspiration

  4. Low Irregular Precipitation

  5. Temperature Extremes • Dry desert air holds little moisture • Water moderates temperature • 50 F temp change between night & day

  6. Convective uplift Heated Air Rises

  7. Katabatic Airflow WINDY!!

  8. Nutrient Poor Soils • Low rates of decomposition • Low primary productivity • Aeolian soils • Alkali

  9. High rates of evapotranspiration

  10. Not all deserts are the same

  11. What Causes Deserts • Global climate patterns • Distance from ocean • Cooling and re-warming of air • Rainshadow effect

  12. Deserts found at horse latitudes 30 Deg North & South

  13. Distance from Water

  14. But what about Baja??

  15. Cold water cools warm air Cold air forms precipitation

  16. Air low in moisture reaches land

  17. Air on leeward side warms as it drops • 1 deg per 100 M (5.5 def F per 1000 ft) • Warms 2X faster than cools

  18. California’s Deserts East of Sierra Nevada

  19. California’s Deserts • Latitude & local topography induces change • Great Basin Desert • Mojave Desert • Colorado Desert

  20. California’s Deserts

  21. California Desert Profiles

  22. Great Basin Desert • Northernmost distribution • East of Cascade range • Modoc Plateau • Western most distribution of basin & range province • Inyo-White mtns • Panamint Range • High elevation desert • 4000-5000 ft • Lava flows

  23. Great Basin Desert

  24. Modoc Plateau

  25. Great Basin Desert • Higher Elevations • Most above 4,000 ft • Coolest desert • Precipitation mostly as winter snow • Spring growth • Interior basins with no drainage • Predominant plant community- Great Basin Sagebush scrub

  26. Great Basin Sagebrush Scrub Biomass exceeds Coast Redwoods

  27. Artemesia tridentata Miles Bio 13 2007

  28. Mojave Desert • Rainshadow of Sierra Nevada & Coastal ranges • Average elevation 3500 ft

  29. Mojave Desert

  30. Mojave Desert • Warmer desert • Freezing winter, some snow at higher elevations • Transitional desert • Higher elevation Joshua forest • Lower elevation regions dominated by creosote bush

  31. Higher Elevation Mojave Desert

  32. Lower Elevation Mojave Desert

  33. Colorado (Sonoran) Desert • Subdivision of Sonoran desert • Low elevation desert • Subtropical desert • Wet winters, monsoonal summers • Most biologically diverse

  34. Colorado Desert

  35. Colorado Desert • Warmest desert • Large cacti & legume trees • Suaro cactus & mesquite trees

  36. Desert Woodlands • Found between montane forests & lower desert scrub communities • Dominated by mixture of desert shrubs & small xerophytic trees • 3% of California • Located between 2,500- 8,000 ft

  37. Pinyon Juniper Woodland • 4,000-8,000 ft • Predominantly transmontane distribution with cismontane distribution in Southern California • Density varied according to local climate • Juniper more xerophytic than Pinyon pine • Juniper dominates in drier lower elevations • Pinyon dominates in moister higher elevations

  38. 10 F per 1000 feet!

  39. California Juniper

  40. Pinyon Pine

  41. Mmmm……

  42. Pinyon Jay • Cache pinyon seeds • Specialized esophagus • Social & gregarious • 500+ • Mated pair share caches

  43. Joshua Tree Woodland • Higher elevations of Mojave desert & Eastern Sierra Nevada • Precipitation mostly as snow • Cold winter temperatures • Coarse, non-alkali soils

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