Results
Non-parametric multidimensional scaling (NMDS) is a multivariate ordination that depicted relationships between measured parameters and treatments, which does not require normality or equal variances. NMDS indicated there may be some differences of the community surrounding fireweed growing alone compared to the vegetation surrounding the other seedlings containing green alder (Figure 3). Ellipses were overlapping, but the vegetation community surrounding fireweed appeared to be more different than the vegetation surrounding the other stock types. Black vectors reflected that there was more grass cover than native forb cover. Lastly, the hitchhiker seedling parameters (blue vectors) also reflected the positive correlations of growth characteristics from Figure 1.
Statistical analysis indicated that fireweed growing alone resulted in differences in community composition compared to the 2 week and 4 week stock types (Table 1). Although the ‘same time’ (0 week) treatment was not statistically different from the vegetation surrounding fireweed growing alone, the p-value indicated that the community surrounding fireweed was more different than the community surrounding the 0 week seedlings.
The vegetation surrounding fireweed was different from the other stock types likely due to a greater amount of non-native vegetation present. However, further annual vegetation surveys will be able to better describe the interactions between stock type and surrounding community vegetation - time will tell. The variation of soil types between blocks may explain the large variance noticed throughout the data, but this will also be explored with soil sampling summer 2018.
Statistical analysis indicated that fireweed growing alone resulted in differences in community composition compared to the 2 week and 4 week stock types (Table 1). Although the ‘same time’ (0 week) treatment was not statistically different from the vegetation surrounding fireweed growing alone, the p-value indicated that the community surrounding fireweed was more different than the community surrounding the 0 week seedlings.
The vegetation surrounding fireweed was different from the other stock types likely due to a greater amount of non-native vegetation present. However, further annual vegetation surveys will be able to better describe the interactions between stock type and surrounding community vegetation - time will tell. The variation of soil types between blocks may explain the large variance noticed throughout the data, but this will also be explored with soil sampling summer 2018.
Figure 3. NMDS ordination using Euclidean distances of the community composition surrounding hitchhiker seedlings relative to stock type (n=6).
Table 1. Community vegetation groups were compared between stock types using multiple perMANOVA tests with pairwise comparisons and a Holm adjustment.
Table 2. Average vegetation cover (%) of native, non-native, grass and woody functional groups surrounding each stock type.