Assessment of plant and soil invertebrates diversity at development stages of natural beech stand, Haftkhal Forest (Mazandaran)

This research was carried out with the aim of studying the status of natural regeneration and biodiversity (plants and soil invertebrates) of beech forest in three development stages including initial, optimal and decay. After identifying the development stages, one 1 ha sample plot was established in each development stage. Within each sample plot, 10 100 m2 micro-sample plots were laid out as random-systematically. The values of natural regeneration, plant and soil invertebrates diversity in optimal, initial and decay stages have been recorded and eastimated in 30 micro-sample plots. The results of this research showed that natural regeneration in the optimal stage was significantly greater than other stages (7.5 seedlings per 100 m2), while the differences of natural regenerations between the stages of initial (2.9 seedlings per 100 m2) and decay (2.8 seedlings per 100 m2) were not statistically significant. The plant diversity (Shannon-Wiener index) in the optimal stage had the highest values (2.375), whereas the decay stage had the lowest value (1.929). But the differences in the initial stage with other stages were not statistically significant. Also the differences of soil invertebrates diversity (Shannon-Wiener and Simpson indices) were not statistically significant in the studied stages. The decreasing of soil invertebrates diversity (Shannon-Wiener index) in these treatments was respectively as optimal, initial and decay. This research emphasizes the values of natural regeneration, plant and soil invertebrates diversity in optimal stage is better than initial and decay stages.