Analyzing the Biological and Structural Diversity of Hyrcanian Forests Dominated by Taxus baccata L.

Abstract

The Hyrcanian Forests, well-known for its World Heritage site in the South Caspian region of Northern Iran, are refugia for a special tree flora. Some areas in particular feature a concentration of large and numerous trees of Taxus baccata, a species that has attracted the interest of many researchers given its medicinal importance. The objective of this study was to analyze the biological and structural features of these unique ecosystems based on three large tree-mapped field plots using new methods. We developed a species abundance distribution and three species–area relations, and analyzed the small-scale structural patterns of each of the 15 tree species that occur in the plots. Species-specific details are presented for each of the three field plots, including the tree densities and average tree sizes, as well as the associated structural indices “species mingling”, “dominance”, and “size differentiation”. This includes non-linear relationships between tree density and neighborhood mingling, and between the average tree size and neighborhood dominance, and a linear relation between the neighborhood dominance and the mean neighborhood differentiation. Based on the findings, we recommend the use of these methods and indices for analyzing the structure of natural forests in other regions of the world.

Species abundance distributions: investigation of adaptation mechanisms of plant communities

“…Our conclusion that species abundance distributions are not unchanged in the course of secondary successions is well consistent with literary data relevant to other regions [10,12,13,15].…”

“…SAD analysis allows you to identify differences in the organization of the plant community. SAD graphs are curves that are defined by many rare species and several dominants [10,12,13]. Analysis of these distributions allows inferences beyond those that flow from many simple diversity indices [10].…”

Genetic Diversity and Structure of Rear Edge Populations of Sorbus aucuparia (Rosaceae) in the Hyrcanian Forest

“…S. aucuparia in refugial regions of Europe [ 52 ]. This is not surprising because the Hyrcanian region was a potential refugium during the last glacial maximum for a wide range of woody taxa [ 2 , 53 ]. An interesting result is the increase in Ho, Ar, and Ap (except the KH population) from the western to the eastern limit distribution of the S. aucuparia in Iran.…”

Structural diversity and conservation implications of Parrotia subaequalis (Hamamelidaceae), a rare and endangered tree species in China

“…Analyzing species composition, structure and function of endangered plant communities is essential for understanding the growth of a target (endangered) species, its relationship with surrounding tree species and predicting its population dynamics (Hui et al 2019;Alavi et al 2020). Generally, on a small scale, the horizontal and vertical structure of a forest community is largely influenced by the arrangement, position, and mixture degree of the surrounding tree species and their competition for light, water, minerals, space and other environmental resources (Pommerening 2002;Ruprecht et al 2010).…”