The Importance Of Saguatus Life

853 WordsDec 5, 20174 Pages
From table 1 we found that the average height of the saguaro found in our plot was 4.75 meters which is roughly 60 years old based on the figure provided. However, this is skewed because we found some really old cacti since cactus life span is about 150 years old. This causes shifts in our distribution to cause a very long tail which can be seen in Graph 1. Based on that graph we can also see a drop in frequency of saguaro in age range of 81-90 and then an increase between 91-110 which doesn’t fit with the trend model found on Tumamoc Hill (from Pierson and Turner 1998). This could be due to environment factors. Based on a PDSI reading of climate history in Tucson from Pierson and Turner 1998 we saw that roughly in 1925 a little over 90…show more content…
The disease nearly 50 years ago but had a strong influence with increasing infection rate 75% 42 years ago in 1975 (Yoshimura 1975). This disease doesn’t affect saguaro today but a current bacteria is causing necrosis in saguaro called Erwinia cacticida which can cause a decrease in the next few years reproduction ability. Another possibility of abnormalities in age is due to animal interaction with the cactus. If seed dispersal birds or mammals decrease or increase in its population could affect the population growth of the cacti. For example a common saguaro seed dispersal is the migratory white winged dove which happens to be decreasing since 1968. These birds are one of the pollinate the saguaro more often than other bird species and highly rely on the seeds for nutrient during migration. Without the help of the birds the cactus population can crash with less pollinators interacting with the cactus (Rabe and Sander 2010). Even though this is more of a recent phenomena we haven’t seen its effects on the population growth. The saguaro still have bats, insects and other birds as pollinators and coyotes, cactus wrens, birds, and wind that help distribute the seeds. A predatory factor are rodents who prey on young cactus seedlings for water. Rodents are abundant and in the desert heat they could really damage the population growth of the saguaro (Niering 1963). Another potential

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