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Transcript of Encelia Farinosa
When we plotted our data, mean vs. rainfall, we saw no trend. Also, when we reversed the axes, we saw no trend in our graph.
Density(mean) and rainfall are both independent variables. Because RSquare was very close to zero, both variables have no linear relationship.
How does time since burned affect Encelia density?
Time Since Burned Effect on Density
Effect of Rainfall on Density
One Thursday morning, we walked through campus and eventually reached a hill that we had to hike. We were then assigned an area based on flag color and marked a 4 meter radius circle. The height, width, and health of the Encelia Farinosa were recorded and the slope and aspect were also measured.
We then compared our data from the combined section's data and used rainfall, mean and year since burned. We then used the data to plot the graphs: mean vs. rainfall & time since burned vs. mean.
We then analyzed the trends.
There are no biological reasons for the trends observed since there was no trend in the graph to begin with.
We did not find a case study supporting the question asked about the effects of density by cause of rainfall.
According to our results, we would expect the same results in a different year because from our data, it had no correlation.
The results would be the same on a different hill in the same biome and in a different biome.
The topic is important to determine whether or not fire is beneficial for Encelia density growth.
Ho: Fire since burned does not promote density growth
Ha: Fire since burned does promote density growth
Encelia is a good off site colonizer of post fire communities via wind dispersal. It can sprout from the root crown. When dispersed, seeds invade post fire communities and become well established. Density is decreased dramatically after a fire but will increase population density greater than initial density in several years.
Encelia has a positive correlation for post-fire growth.
We would expect a slightly higher density from the year before.
We would see the same trend if Encelia were on a different hill with the same biome.
We would see different results if Encelia were in a different biome.
BIO 5C SPRING 2013
How does time since burned affect Encelia density?
How does rainfall affect Encelia density?
The topic is important to understand whether or not how much water is necessary for Encelia density to increase.
Ho: Increase in rainfall will increase the density of Encelia.
Ha: Decrease in rainfall will decrease the density of Encelia
Background on 5C Hill
The slope of the hill was 8 degrees.
Transect: Burn Shrub 8BS
There should be a positive correlation between rainfall and density.
There will be a negative correlation between time since burned and density.
have designated plots: (1) an area where plants are burned with prescribed fire and left to regrow for an amount of years (2) plants would be maintained but not burned and allowed the same time for growth (3) an area where it would be random wildfires burning the plants during the course of the study.
All prescribed fires would occur in June, to make it easier to check each area for growth after 6 months.
We would compare densities after the amount of years for allowed growth.
Since we are performing our experiment in designated plots, we would need a permit for authorization of our experiment
According to the graph, there is a positive correlation between mean and year since burned.
Our RSquare = .079, showing that there is some level of a linear relationship between year since burned and mean
Although our hypothesis stated that there was going to be a negative correlation between year since burned and mean, according to the graph we were proven wrong
Materials: E. farinosa, soil, water system.
Five samples: control group, no rain, little rain, moderate rain, heavy rain.
We would collect our data in a single green house.
We would account for the number of dead, alive, and new sprouting plants every 6 months in the morning.
We would be regulating the amount of rainfall given to a set of plants.
Since we are performing this in a controlled environment, we would not need a permit assuming that the greenhouse belonged to us.
Leaves and flowers are formed when water relations are favorable. Under drought conditions, Encelia becomes dormant and leaves are shed. With rainfall, leaves are expanded, less pubescent, less capable of reducing water loss, and have lower resistance to carbon dioxide flux.
Question 1: Does Rainfall have a direct correlation to the increase in Encelia population?
This question is important in understanding the living conditions of Encelia over various seasons. The results of this test will be similiar to the previous analysis observed.
Question 2: Will seasonal fires affect the presence of Encelia within a given area?
This question is important for ecologists in that they can observe the affects fire has on this species and whether or not fire will pose a threat to the existence of this species. The previous analyses will support the results in this test.