The difference in vegetation density in burnt and unburnt - Assignment Example

The Difference in Vegetation Density in Burnt and Unburnt Areas Introduction The main objective of the study was to measure plant species data by comparing the two habitats that include unburnt and burnt area using Mann-Whitney test.The plant species considered include Xanthorriea,Acacia pycnantha and Black rapier sedge.These study,enabled the determination of the difference in vegetation density between the burnt and unburnt areas Descriptive statisticsFigure 1.Histogram indicating the frequencies of the two(Un-burnt and burnt) dependent variableIn the two diagrams above (figure 1), the score distribution for un-burnt and burnt have different shapes.

In this case, the Mann-Whitney U test can be applied to compare the mean ranksBasing on the graphs above, it is clearly evident that the following output and interpretation is related to Mann-Whitney U test results and it is indicated by the two distributions which have a different shape. In this case, the mean ranks were compared but not the medians.Descriptive StatisticsNMeanStd. DeviationMinimumMaximumPercentiles25th50th (Median)75thVAR00003693.383246.8457542.10160.3857.668976.7322146.2152VAR0000561.5000.547721.002.001.00001.50002.

0000Table 1.Descriptive statistics of the variablesBasing on the descriptive statistics table above, we chose Mann-Whitney U test because one group was not normally distributed.Inferential statisticsMann-Whitney TestRanksVAR00005NMean RankSum of RanksVAR000031.0034.3313.002.0032.678.00Total6The above table indicate the group with the highest density of plantation, overall; the group with the highest rank. In this regard, the un-burnt area is observed to have the highest density of plantationTable 3.

Test statistics tableTest StatisticsaVAR00003Mann-Whitney U2.000Wilcoxon W8.000Z-1.091Asymp. Sig. (2-tailed).275Exact Sig. [2*(1-tailed Sig.)].400ba. Grouping Variable: VAR00005b. Not corrected for ties.The above table indicates the actual significant values of the test. The table provides the test statistics, U statistics together with asymptotic significant p-value (2-tailed)DiscussionBasing on the data above, it can be concluded that plantation density in the un-burnt area was not statistically significantly higher than the burnt area(U=2,p=0.4).This implies that further studies need to be done to determine the repeatability of the results in order to confirm if the results are valid.

According to literature it is clearly evident that frequent fires might have an impact on the young plants including higher size class (Trollope et al., 1998). The frequency of fire usually determines the length of time the plant is required to recover before the next fire occurs. The slower the rate of recovery, the more likely it is that the composition and structure of the vegetation will be changed, specifically where fires occurs often.Work Cited Trollope W.S.W., Trollope L.A., Biggs H.C.

, Piennar D. and Potgieter A.L.F Longterm changes in the woody vegetation of the Kruger National Park, with special reference to the effects of elephants and fire, Koedoe, 41, pp103112. 1998.