Diversity and Distribution of liverworts across habitats and altitudinal gradient at Pachmarhi Biosphere Reserve ( India )

drakasthanaster@gmail.com Abstract The present study elucidates the distribution of liverworts (Marchantiophyta) in various habitats and across the altitudinal gradients at Pachmarhi Biosphere Reserve (PBR), central India. The liverwort diversity was assessed in selected habitats at each site viz. soil, wet rocks, dry rocks, soil covered rocks, stony walls (terricolous habitats) and epiphytic habitat. Three altitudinal gradients were considered for distributional assessment. In all, 41 liverworts belonging to 21 genera and 15 families were encountered. Among the three altitudinal zones, 17 taxa were found at lower altitudinal gradient (400-800 m) whereas 12 liverworts were found at the higher altitudinal gradient (1001-1400 m). Maximum taxa (33) were present at the middle altitudinal zone (8011000 m). The sites at middle altitudes furnished amicable conditions for the growth of bryophytes. In general, rocks, both moist and dry formed the most pertinent habitat for the liverworts. Evidently, the middle altitudinal gradient emerged as the altitudinal range harbouring maximum liverworts.


Introduction
Pachmarhi Biosphere Reserve (PBR) lies in the Hoshangabad, Betul and Chhindwara Districts of Madhya Pradesh and was designated under MAB Programme in 1999.The present study elucidates the distribution of liverworts (Marchantiophyta) at various habitats across the altitudinal gradients in this Biosphere Reserve.This region is considered as the richest region of central India in terms of cryptogam diversity.PBR encompasses three conservation units viz. the Pachmarhi Sanctuary, Satpura National Park and Bori Sanctuary along with the areas surrounding these.As far as the cryptogamic flora of PBR is concerned, researchers have ventured into the studies of algae, lichens, bryophytes and pteriodophytes from later part of the 20 th century.The studies on bryophytes at PBR were initiated way back in 1950s by Pande and Srivastava (1952) probably due to the substantial number of bryophytes anticipated from the region.Further workers listed few species of bryophytes, mainly the liverworts from the area, viz.Lal and Parihar (1979), Jain and Kaul (1985), Patidar et al (1985) and Kaul et al. (1995Kaul et al. ( , 1995a)).In the past decades listings of bryoflora of Pachmarhi and neighbouring areas have been provided by Kaul (2001), Singh and Kaul (2002) and most recently by Sharma and Alam (2011).The previous efforts on studies of bryophyte flora have been done keeping in mind the taxonomic parameters and morphological assessment of the species.The PBR region exhibits variable topography and numerous applicable habitats and the region is at an elevation of 300-1400 m a.s.l, hence assessment of the distributional pattern of plants of the region is an interesting aspect.The present study deals primarily with this aspect of liverworts of PBR and aims at elucidating the important trends and patterns of liverwort distribution across the altitudinal gradient and at different selected habitats of this reserve area.Taxonomic diversity of liverworts has been discussed emphasizing the dominant families and genera and elaborating the habitat and altitudinal distribution of the taxa.The present work aims to discuss the habitat differentiation of liverworts in PBR and assess the possible effects of the altitudinal gradient on the liverwort distribution.

Materials and Methods
Plant collections were done in successive years from 30 sites of PBR covering an altitudinal range of approx.300 to 1400 meters a.s.l.The total study area was divided into three altitudinal zones and from each zone, equal number of sites were selected for collection of bryophytes.The liverwort diversity was assessed on six selected habitats at each site viz.soil, wet rocks, dry rocks, soil covered rocks, stony walls (terricolous habitats) and epiphytic habitat.The collections have been deposited in the Bryophyte Herbarium, National Botanical Research Institute, Lucknow (LWG), India.

Results and Discussions
During the study, 41 liverworts belonging to 21 genera and 15 families were encountered.In general, rocks, both moist and dry formed the most pertinent habitat for the liverworts, with 33 species being present on rocks.Soil covered rocks also formed preferential habitat followed by soil (Fig. 1).Only three epiphytic taxa were encountered, viz.Lophozia mayebarae (S.Hatt.)N. Kitag., Lejeunea wightii Lindenb.and Frullania ericoides (Nees ex Mart.)Mont.Stony/ brick walls did not harbor any taxa probably due to lack of proper substratum that can bind the thallus.
Among the three altitudinal zones, 17 taxa were found at lower altitudinal gradient (400-800 m) whereas 12 liverworts were found at the higher altitudinal gradient (1001-1400 m).Thirty three taxa were present at the middle altitudinal zone (801-1000 m).The sites at middle altitudes furnished amicable conditions for the growth of bryophytes (Fig. 2).Maximum number of species were common in distribution at middle and lower altitudes.Common taxa were also present at middle and higher altitudes.However, less species were common at sites of collection situated at low and high altitudes, indicating the dissimilar species

Fig. 2 .
Fig. 2. Species distribution of liverworts across the altitudes at PBR

Table 1 :
Observations of the study