Floristic status of the Himalayan foothills in Haryana – vegetation composition, diversity and population structure

The current research was performed in the Morni Hills, a part of the outer Himalayas. Floristic assessment is critical for a plant community, reflecting both the gene pool and adaptability of the community. For this, different parameters like density, frequency, basal area, IVI, and various diversity indices were calculated by dividing the area into two altitudinal ranges, i.e. 400–600 m AMSL (AR_1) and 600–800 m AMSL (AR_2). The vegetation sampling was done by randomly selecting 30 plots in the selected area. The study showed that AR_2 (118 plant species: 31 trees, 17 shrubs, 58 herbs, and 12 climbers) had a higher number of plant species in comparison to AR_1 (106 plant species: 26 trees, 14 shrubs, 54 herbs, and 12 climbers) with Poaceae being the family with the greatest number of species. The area was seen to be dominated by Acacia nilotica (L.) willd. Ex Delile, Cassia fistula L., and Leucaena leucocephala (Lam.) de Wit in AR_1 while by Pongamia pinnata (L.) Pierre, Cassia fistula, and Oroxylum indicum (L.) Kurz in AR_2. The upper range, i.e. AR_2 was also more diverse than AR_1 because of a high Shannon Wiener Diversity Index value and a lower Simpson Index value. Whereas the population structure study demonstrated that girth class D (CBH=61–90 cm) had the highest number of tree species in both altitudinal ranges, followed by girth class C (CBH=31–60 cm). Moreover, the forest was also observed to be occupied by various invasive plant species as well as under anthropogenic pressure, hence in immediate need of proper management and conservation.