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soil tested for Group 4 was 6.0. This makes for a slightly acidic middle section. The p-value for the pH was 0.227080. This value is also greater than 0.05, which also proves its insignificance.

When discussing the IV 300 values, as the gradient increased in elevation the species frequency also increased. In the flood plain area this number was 4.5 and the top plain and middle slope had the same values at 6.5. The middle plain had the highest species diversity, at 2250, with the next highest being the top plain at 1850. The flood plain had the lowest diversity at a value of 1300. The species basal area increased along with the gradient with the flood plain at 0.8117109, middle slope 1.54829829 and the top plain at 3.06828291. Figure 3 displays the sum of the relative frequency, density and basal area. It illustrates that the flood plain had the lowest IV 300 values all around and the every variable except species diversity did increase in value along with increasing elevation gradient.

Percent Moisture for the FP, MS and TP

Figure 1. This graph shows the percent moisture found for the flood plain, middle and top sections assigned near Toby Creek. This graph displays two different values found for each area.

pH Values for the FP, MS and TP

Figure 2. This graph shows the pH values of the soil for the three different areas tested.

IV 300 Importance Values for the Flood Plain, Middle Section and Top Section

Figure 3. This graph displays the sum of the relative frequency, density and basal area. The number 1 represents the Flood Plain, 2 represents the Middle Slope and 3 represents the Top Section on the X-axis. The middle section proves that species can coexist and overlap.

Table 1. Data Summary for IV 300 Importance Values.

Species Frequency Species Diversity Species Basal Area

Flood Plain 4.5 1300 0.8117109

Middle Slope 6.5 2250 1.54829829

Top Plain 6.5 1850 3.06828291

Numbers within this table show the number of tress of a species within an area, the sum of species basal area and the number of trees found in a specific plot divided by the total number of plots.

Table 1. Data Summary for % Moisture for the Flood Plain, Middle and Top (3 sample Anova test results)

P-value =

0.679883

1

2

3

Total

N 2

2 2 6

Σx

88.8 40.4 62 191.2

Mean 44.4 20.2 31 31.8667

Σx2

5791.04 985.36 1922.8712 8699.2712

Variance 1848.32 169.28 0.8712 521.2729

Std. Dev. 42.9921 13.0108 0.9334 22.8314

Std. Err. 30.4 9.2 0.66 9.3209

This chart shows the statistical analysis for % Moisture for the Flood Plain, Middle and Top. The p-value is 0.679883.

Table 2. Data Summary of pH for the Flood Plain, Middle and Top (3 sample Anova test results)

P-value =

0.227080

1

2

3

Total

N 2

2 2 6

Σ^x 12.2 12 14 38.2

Mean 6.1 6 7 6.3667

Σ^x2 75.14 72 98 245.14

Variance 0.72 0 0 0.3867

Std. Dev. 0.8485 0 0 0.6218

Std. Err. 0.6 0 0 0.2539

This graph shows the statistical analysis for the top middle and flood plain for the pH of the soil. The p-value is 0.227080.

Discussion

The main purpose of this experiment was to analyze how tree species are grouped along a gradient of 400 meters. This was analyzed by calculating three quantitative characteristics of plant community structure among a gradient; the tree species, soil pH and soil moisture to determine if the vegetation corresponded to either hypothesizes. Plant community structure along with the Toby Creek gradient supported both the individualistic and community - unit hypothesizes. The clustering of species occurred more so within the middle slope of the gradient (2250) but there was a crossing over of species from all three areas of the elevation gradient as displayed within Figure 3. Within the article, Gradient Models, Gradient Analysis, and Hierarchical Structure in Plant Communities, results showed that four models of community structure were supported. These models are, pattern of boundaries of species distributions, pattern of modes of species response curves, whether or not species distributions exhibit hierarchical structure. These models were tested to prove which hypothesis, continuum or community-unit was true. (2)

This study relates to other ecological issues such as the differential diameter - size effects of forest management on tree species and community structure. Human disturbance can cause drastic changes with the community structure in a specific environment. There was construction happening right next to the area that was chosen for this study. Previous studies have shown that logging can affect adult tree communities reverberate upon the regeneration contingent. The study found that species richness in the smaller and larger diameter-size classes was significantly lower in logged areas. (1)

One limitation of the research methods was that the pH and soil moisture was calculated at a different time and gradient near Toby Creek than the basal area, frequency and density of species. This might have affected my results because the soil pH and moisture may not be the same between the two areas skewing the data. In the future, all