The effect of forest gaps size on biodiversity of plant species in Lalis forest-Nowshahr

Forestgaps size and created conditions within gaps are of great importance on biodiversity of understory vegetation. For this purpose and better understanding of biodiversity, different indices were used in highland forests of Lalis located in Nowshahr. Line transect method was used for sampling and plant abundances were also recorded. Forestgap areas were divided into four classes including 50 - 200,200 - 400, 400 - 600and > 600 m2 area. Pearson correlation was applied for indices and area classes. In total, 59 gaps were recorded and 24 species belonging to 15 families were identified in the studied area. Dryopteris affinis had the highest abundance in whole of the classes. The value of species diversity, richness and evenness indices showed highest correlation with increasing gap area with coefficient equal to 1.00.