Do Saguaros Grow Older in Higher Elevations在高海拔地区长大做仙人掌.pptVIP

Do Saguaros Grow Older in Higher Elevations? Erin Benjamin Brian Block Elevation Effect on Saguaro Growth Importance - Saguaros are losing habitat - Humans are developing further into the desert - Conservation - To improve knowledge on how and where to conserve the saguaro species Elevation Effect on Saguaro Growth Hypothesis: Saguaros Grow Better at Higher Elevation Criteria to be Measured Number of Arms Older Saguaros Have a Greater Number of Arms Elevation Effect on Saguaro Growth Background - Saguaros have a slow growth rate - Saguaros have a shallow root system and are less able to tolerate extended periods of drought - Saguaros are not frost resistant - The older a saguaro the more arms (Saguaros over 200 years old routinely have 5 or more arms) Elevation Effect on Saguaro Growth Background - Environmental Variables - The higher the elevation the cooler the temperature - The lower the elevation the lower the amount of moisture in the air - The higher the elevation the stronger the intensity of the sun - The higher the elevation the colder the winters and the higher the chance of saguaro death - The higher the elevation the more rain the monsoon season brings Elevation Effect on Saguaro Growth Methods Two Investigators Examined 200 Saguaros and Counted Arms in Separate Geographic Locations Locations Examined Apache Junction Elevation 1758 Feet Catalina Foothills Elevation 2559 Feet Data Compiled and Evaluated Catalina Foothills Elevation 2559 Feet Results Catalina Foothills 6% of cacti observed had 10 arms or more Apache Junction 38% of cacti observed had 10 arms or more Based on Hypothesis there is a greater percentage of older saguaros at lower elevation examined Results Reject Hypothesis Create New Hypothesis Overview Cooler temperatures effect growth rate The intensity of the sun effects saguaros growth Colder winters lead to saguaro death Study Limitations Data compiled from different regions Only one investigator counted saguaros with