Diversity of Lichens along Elevational Gradients in Forest Ranges of Chamarajanagar District, Karnataka State

The lichen species richness in Chamarajanagar district in Karnataka, India were assessed using altitudinal gradient, in order to compare distribution patterns of different growth forms, dominant families and diversity index. Four major forest ranges, Biligiriranga Hills, Himavad Gopalaswamy Hills, Malay Mahadeshwara Hills, and Shivanasamudra Falls were surveyed and a total of 97 lichens, belonging to 47 genera and 25 families were recorded. Physciaceae was found to be dominant family by 18 species under 8 genera, followed by Parmeliaceae with 16 species under 4 genera. Crustose type was dominated with 51%, followed by foliose type with 38%. Malay Mahadeshwara hills had highest lichen species richness and harboured 67 species, of which, 36 species were crustose type and 28 species were foliose type. Shannon-weiner index ranged from 3.852.45 and Simpson index of diversity ranged from 0.02-0.09. Luxuriant growth of lichens was recorded at the altitude of mid elevation with degree of abundance, density, frequency and distribution of the lichen species compared to other elevation. The present study provided baseline data of lichen diversity, which helps in understanding the relationship between distribution of lichen species along different elevation bands and vegetation types. Keywords— Biodiversity, Deciduous forest, Physciaceae, Corticolous, MM Hills


I. INTRODUCTION
Lichens, one of the most successful symbiotic associations of a fungus, a green and/ or blue green alga, are known to inhabit nearly all the terrestrial domains of the planet [1]. Lichens are the early land colonizers of terrestrial habitats and perhaps the oldest living creatures on the Earth [2]. To know the spatial patterns in biodiversity along environmental gradients, is a central theme in ecology [3]. Elevation gradients distributed across the globe are a powerful test system for understanding biodiversity [4]. Elevation gradient studies on diversity and distribution of lichens has been undertaken across the world [5][6][7][8]. In Karnataka, diversity and distribution pattern of lichens was studied only in midelevation wet Evergreen forest of Southern Western Ghats [9]. Southernmost part of Karnataka state lies Chamarajanagar district. The forest regions in this district run east from the Western Ghats to the river Cauvery and forms a forest ecological corridor that connects the Eastern Ghats and Western Ghats. This district is unique because it has scrub, dry deciduous, moist deciduous, semi-evergreen, evergreen and shola forests. It is also known for its many endemic species of plants including valuable medicinal ones. Forests in this district have been conserved to protect habitats like flora, fauna and cryptogamic forms like algae, bryophytes, pteridophytes and lichens. Lichens can provide valuable information about medicinal values and environmental conditions around the forest area. Enumeration of lichens in this region is not reported. Hence, in the present study forest ranges with different elevation gradients has been undertaken in Chamarajanagar district, with particular reference to understand the species richness, diversity, abundance, frequency, growth form and ecological adaptation of lichens.

Topography of the Study Area
Chamarajanagar is the southernmost district in the state of Karnataka, India. Chamarajanagar district is divided into 3 taluks: Yelandur taluk, Kollegal taluk and Gundlupet taluk ( Figure 1). Major and popular mountain ranges from each taluk has been selected for the study. Sampling sites were distributed at various elevations in the district.

Lichen Sampling
Field trips were executed to collect lichen growing on different substrata were sampled by belt transact method. Each transect measuring 50x10 m laid in different locations of the study area. A total of 20 transects was laid in 4 different locations in the study area. All species of lichens found in sampling area were harvested and species that are tightly adhered to bark or rock were collected with the help of chisel and hammer. Immediately after collection, samples were cleaned and wrapped in a tissue paper and stored in paper bags. Collected specimens were numbered and preserved in lichen herbarium packet (17cmX10mm) with details of the locality and deposited in the herbarium of the Department of studies in Botany, Manasagangotri, University of Mysore, Karnataka, India.

Identification of Lichen Species
The external morphology was studied using a stereomicroscope. The anatomy of the thallus and apothecia were studied under a compound microscope. The anatomical structures were studied after taking the section of dry material with the help of safety razor blade and the sections were mounted in water or on cotton blue in lactophenol. The colour of medulla, epithecium, hypothecium and ascus were recorded. The shape and size of the asci, ascospores and conidia were measured. The measurements of the thallus, medulla, epithecium and hymenium were generally recorded from the sections mounted on cotton blue. The thallus size was measured in centimeter, lobe size and ascocarps in millimeter and thallus medulla, epithecium, hymenium thickness, asci and ascospores size in millimicron. Chemical test of the specimens includes-colour spot tests (K, C, KC and P test) and thin layer chromatography (TLC) test through cold extraction method. Identification was carried out by consulting suitable keys to identify lichens [10][11][12][13].

Data Analysis and Interpretation
Lichen assemblages were quantitatively analyzed for density and frequency. Relative frequency (RF) and relative density (RD) were determined [14]. RF=100 x (frequency of species I/sum of frequency values of all species), and RD=100 x (density of species I/sum of density values of all species). The importance value index (IVI) used here is the sum of the relative frequency and relative density. Frequency distribution, alpha diversity -Shannon-Weiner diversity index (H') and Simpson diversity index (D') have been used to assess species diversity [15]. Alpha diversity (H') was estimated as the Shannon-Wiener index: H'=Ʃpi ln pi, Where, pi=density (number of thalli) of the species, i/density of all species. All statistical analyses were performed using SPSS.

III. RESULTS
The present study deals with the systematic survey of lichens in forest ranges along with elevational gradient in Chamarajanagar district in Karnataka state which is bordering with Kerala and Tamil Nadu states. A total of 97 lichens, belonging to 47 genera and 25 families were recorded from 35 transects of 4 localities namely; Biligiriranga Hills, Male Mahadeshwara Hills, Shivanasamudra Falls and Himavad Gopalaswamy Hills (Table 2).  (Figure 2).

Fig 2: Dominant lichen families with respect to species richness in Chamarajanagar district
Crustose type growth forms were abundant with 51%, followed by foliose type growth forms with 38%, fruticose type growth forms with 8% and squamulose type growth forms with 1% (Figure 3). High diversity of lichens was encountered in Male Mahadeshwara hills with 67 species, in which crustose growth form was more with 36 species and foliose with 28 species (Figure 4). The different types of lichens recorded in this region were from the mid elevation level (950-1100). The forest type varies from evergreen forests to dry deciduous forests. The next richly dense place with lichen colonization of 55 species was Biligiriranga hills commonly called BR Hills. The forest vegetation types here were; scrub, deciduous, riparian, evergreen, sholas and grasslands. Among all the study sites, BR hills had the high range mountain peaks and at high altitude (1350-1450 m) only few lichens of Heterodermia and Parmotrema were recorded less density and abundance. Density of macrolichens was more compared to microlichens. But in mid elevation (1100-1350m) abundance, density, frequency and distribution of lichens was recorded luxuriantly. At low elevation (800-1000m) density and abundance of crustose lichens was more. The next highest elevated region (1500m) is Himadgopalaswamy hills which is situated in the core area of the Bandipur National Park and is frequented by wildlife. Dense fog predominates and covers the hills round the year, with moist deciduous forest type. In this forest range, density of macrolichens was found to be more with 25 species compared to the microlichens with 20 species at elevation of 1350-1450m). Shivanasamudra falls has a segmented water fall of river Kaveri with Scrub forest. Not much lichen colonization was found, density of lichens was very poor with 14 species.

IV. DISCUSSION
In the present study, it was observed that, the species richness increased as elevation increases, up to a certain point, creating a "diversity bulge" at middle elevations [16]. Elevation was more important than forest structure in driving taxonomic and functional diversity. While the species richness with increase elevation, decrease in functional diversity revealed that community patterns shift with elevation from random to clustered, reflecting the selection for key shared traits. Higher elevations favoured species with a complex growth form (which takes advantage of high moisture) and asexual reproductive mode (facilitating establishment under low temperature conditions) [17].
As elevation increased, total area decreased; thus, there were more species present at middle elevations than at low and high elevations. There are generally three patterns of species richness; a monotonic decline in species richness from low to high elevation, a hump-shaped pattern with maximum at mid-elevations and a constant from the lowlands to mid elevations followed by a strong decline further up which indicates that the maximum number of species had been confined in the mid elevations [18]. The elevation was also clearly effective on both the number and the composition of the epiphytic lichen communities. Climatic parameters like; temperature, rainfall, evaporation, are known to be closely related to altitude. For this reason, the number of species was more in the highest zone. The preferences of some species were reported to be concentrated in 1300-1600m and 1800-1900m elevation zones [19].
Families such as Graphidaceae, Thelotremataceae are generally observed to be found commonly in lowland forests [20] which corroborate our study in that, the population of crustose lichens was found to be more in low elevated areas, especially in BR hills and MM hills. Similar observation was reported from Chogoria, a wet forest type in Mt. Kenya forest, where high abundance of crustose micro lichens at lower elevation was observed and macro lichens were abundant at higher altitudes [21]. Further, it was apparent that, the numbers of foliose lichens are increasing with the increase of altitude. In most temperate and boreal forests, with light exposed trees, had richer lichen vegetation than the trees of the interior forest [22]. Mid-elevation peaks had a unimodal peak in diversity at intermediate elevations (4300m) with 25% or more species than at the base and the top of the mountain [23]. In a similar work, the effect of elevation was studied on lichen diversity in seven spatially separated sites of Zanskar valley, in Ladakh region of the Himalayan state of Jammu and Kashmir and found a significant linear relationship between total lichen diversity and elevation, where a gradual decrease in lichen diversity was observed with increase in elevation [24].
Elevational gradients of terricolous lichen species richness in the Western Himalaya and the total species richness showed a unimodal relationship with elevation, where the highest species richness was observed at mid elevations (3,200 m) [25], which is similar to our observation in the present study. Unimodal relationship of lichen species richness with elevation was also reported from Nepal [26], where the maximum modelled total richness occurred in 3100-3400m, whereas the observed maximum richness (144 species) was at approximately 4000m. The lichen diversity in the crowns of trees at mid elevation seems to be somewhat similar to that at lower elevation although tree species are different. At mid elevation, tree trunks get only diffused light while the canopy gets more direct light. The difference in distribution and diversity observed on barks could be mainly due to light condition prevailing at mid elevations [27]. The number of lichen species showed decline towards the high elevation gradient, in which rock inhabiting species exhibit their dominance in higher altitude while, soil inhibiting lichens dominated in the lower altitude [28].
The majority of the parmelioid genera and species of Taiwan are distributed primarily in submontane-montane elevations (500-2,500 m) located in the meridional climatic zone [29]. Basic groundwork must be comprehended in order to meet the nation's needs and also to strive towards the biotechnology industry. Better lichen sample representation of the lichen should be collected. Furthermore, since the lichens can only be identified through its fruiting bodies, the task of collecting sterile lichens should be avoided [30].

V. CONCLUSION
The present study indicates the richness of lichen diversity in the Chamarajanagar district of Karnataka state. It had varied vegetation with different forest types namely; scrub, dry deciduous, moist deciduous, semi-evergreen, evergreen and shola forests. The study revealed that, as the elevation increased from lowland to mountain peak, the total area also decreased, leading to highest lichen species richness in terms of abundance, density, frequency and distribution at mid elevation, where luxuriant growth of lichen species was observed when compared to lowland and high elevation mountain peaks. The enumeration lichens species gave a baseline of lichen diversity of Chamarajanagar district of Karnataka, which is a lichenologically unexplored region and addition to Indian lichen inventory.