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Differences in the Assemblages of Species Found in Recovering and Stable Boundaries of the Sepulveda Basin GEOG 330: Jason Callanan, Jackie Bartz, David Henderson, Liliana Camacho, Chris Gonzales Chris Gonzales, David Henderson, Jason Callanan, Lili Camacho, Jackie Bartz
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Location Sepulveda Basin located in the San Fernando Valley 40 miles northwest of CSULB
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History of the Sepulveda Basin
Two main areas that are part of the Wildlife Reserve Area A underwent agricultural disturbances such as grazing, wheat, corn, sod planting Restoration efforts began in the 1980s MP and EIS focused on Area A (> size) Area B developed as a revegetation experiment by the Army Corp of Engineers in 1979 Public safety concerns Army Corps of Engineers, bulldozed Area B in 2012
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Hypothesis Are there differences in the assemblages of species found in recovering and stable boundaries? In other words, is there a significant difference in the three species found in Area A, the recovering area, and Area B, the area that fails to show expansion?
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Major Species Baccharis pilularis Erodium circutarium Bare dirt
Coyote brush Erodium circutarium Coastal heron’s bill Bare dirt
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Data and Methods Data was collected Tuesday March 29th 2016 in the Sepulveda Basin Area A (north of Burbank) and Area B (south of Burbank) We used the transect method for data collection (10 meter transect line, Garmin GPS, transect papers) 12 transects total (6 in area A and 6 in area B) For each transect we documented the critter we found at every meter mark (11 samples per transect and 132 samples for the entire study) Unknown critters were placed in a bag for further examination.
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Data and Methods We organized our data in an Excel spreadsheet to determine what our three most documented critters were among area A and B. Performed a Chi-squared test to see if there was a significant difference in the amount of these critters between the two areas. We then used our statistics knowledge to analyze and interpret the results of our test and to draw a conclusion. This included looking at values such as Chi- squared calc, Chi-squared crit, effect size, alpha level, and the power value to determine the significance of our findings and if we could trust our results.
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Results & Discussion Species counts are as follows (Table 1)
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Statistical Analysis
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According to our analysis…
Null Hypothesis: Area A and Area B are independent of one another (No Change) Alternative Hypothesis: Area A and Area B are not independent of one another (Change) Chi Squared Calculated Value > Chi Squared Critical Value 8.904 > 5.991 P value < alpha < .05
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Reject Null Hypothesis?
NO… Cramer's phi measure of Effect= 0.336 Estimated power = 0.776 Large probability of making a type I error; false rejection of true Null Hypothesis.
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Bias Recovering Agriculture Site:
Chose to conduct transect lines along stable boundary of site Recovering Army Corp Degraded Site: Chose transect lines where disruption was the most intense Impact: Possible misrepresentation of actual population of native and non-native species
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Discussion Time of Disturbance:
i) Former agricultural land was abandoned in 1994 More time to recover since our research allowed a larger population of both native and non-natives to establish themselves. ii) Army Corp impact occurred in 2012 Due to how recent the disturbance happened we see a larger amount of bare ground and less native vegetation because it has had less time to re-establish itself
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Conclusion We failed to reject the null hypothesis
There are no significant differences in the assemblages of species found in Area A and Area B
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Future Studies Null hypothesis cannot be rejected due to:
–Insufficient data –Time of disturbances –Types of disturbances –Biases Future ESP classes should continue CSS research; more data is necessary to sincerely reject the null hypothesis.
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AngelFest Three-day family music festival proposed to occur adjacent to Wildlife Reserve 65,000 individuals expected per day Will present an impact on the migratory and residential birds of the Sepulveda Basin American white pelican Osprey Western Bluebird Savannah Sparrow
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Proposed AngelFest Set-up
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AngelFest Delayed Until 2017!
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