Effects of inventory grids on estimation of tree species diversity in semi-arid forests of Iran

Abstract

Mirzaei, M., Bonyad, A.E., Moradi Emamgheysi, I., Hassanzad Navroodi, I., 2019. Effects of inventory grids on estimation of tree species diversity in semi-arid forests of Iran. Folia Oecologica, 46: 24-29.Species diversity is one of the most important indices used to evaluate the sustainability of forest communities. The sampling method and the number of plots are factors affecting the estimation of plant biodiversity. In the present study, effects of different inventory grids on estimation of tree species diversity were compared in semi-arid forests of Iran. There were selected 50 hectares of these forests representing the regional forests. Sampling procedures were carried out on circular plots (1,000m 2 ) within inventory grids, with dimensions of 50 × 50 m (200 plots), 100 × 50 m (100 plots), 100 × 100 m (50 plots), 200 × 50 m (50 plots), 200 × 100 m (25 plots), and 250 × 200 m (10 plots). For each plot, the type of the species and the number of trees were recorded. Simpson (1-D), Hill (N 2 ), Shannon-Wiener (H ' ), Mc Arthur (N 1 ), Smith-Wilson (E var ) and Margalef (R 1 ) indices were used to estimate the tree species diversity. The inventory grid was evaluated based on the precision and cost criteria (E% 2 × T). The obtained sampling error values showed that the inventory grid consisting of 200 plots exhibited more accuracy for estimating the biodiversity indices. But based on the results of E% 2 × T, the inventory grid with 25 plots was selected as the most appropriate one for estimating the tree species diversity in semi-arid forests. The results of this study can also serve to estimate the tree species diversity in other semi-arid forests of Iran.

Effects of plot size on assessment of tree species diversity in Caspian forests of Iran

“…One of the most critical issues in natural resource conservation is integrating economic development along with the protection of biodiversity on earth (Mirzaei et al 2019a). Loss of biodiversity and destruction of habitat has increased due to an increase in human population and increased human demand for natural resources, such as in agricultural practices (Asifat et al 2019;Mamnun and Hossen 2021).…”

“…Biodiversity in forests helps to maintain key ecosystem processes and functions such as atmospheric gas exchange, nutrient cycling, climate regulation, hydrologic cycles, and soil genesis and development. Each species plays a vital and crucial role in the food chains of ecosystems because the extinction of one species might disturb the life balance in nature (Mirzaei et al 2019b).…”

“…Ebrahimi et al (2014) used 25 circle plots of 1000-m 2 to estimate tree and herbaceous species diversity in the north forests of Iran and showed that the effect of land protection on plant diversity was more pronounced for evenness than for species richness and the positive correlation between diversity and evenness indices was higher than that between diversity and richness. Mirzaei et al (2019a) studied the effects of inventory grids on tree species diversity in semi-arid forests of Iran and showed that based on the results of E% 2 ×T, the inventory grid with dimensions of 200×100m (25 plots) was selected as the most appropriate one for estimating the tree species diversity in semi-arid forests. Mirzaei et al (2019b) by using 30 circle plots of 1000-m 2 , three variables, including the number of individuals (frequency of species), basal area and volume of tree species, were compared to estimate tree species diversity in broadleaves forests of Iran and showed that basal area and volume variables were selected as more suitable variables in order to estimate of biodiversity indices in northern forests of Iran.…”

“…Mirzaei et al (2019a) studied the effects of inventory grids on tree species diversity in semi-arid forests of Iran and showed that based on the results of E% 2 ×T, the inventory grid with dimensions of 200×100m (25 plots) was selected as the most appropriate one for estimating the tree species diversity in semi-arid forests. Mirzaei et al (2019b) by using 30 circle plots of 1000-m 2 , three variables, including the number of individuals (frequency of species), basal area and volume of tree species, were compared to estimate tree species diversity in broadleaves forests of Iran and showed that basal area and volume variables were selected as more suitable variables in order to estimate of biodiversity indices in northern forests of Iran. Such literature showed a range of optimal plot sizes in forests that varies depending on the response variable of interest, suggesting that relatively small plots can be used to estimate the density of regeneration, while relatively large plots are needed to detect patterns in the spatial structure of trees.…”