The woody flora of Shettihalli Wildlife Sanctuary , central Western Ghats of Karnataka , India-A checklist

Documenting the biodiversity of protected areas and reserve forests is important to researchers, academicians and forest departments in their efforts to establish policies to protect regional biodiversity. Shettihalli Wildlife Sanctuary (SWS) is an important protected area located in the central Western Ghats of Karnataka state known for its diverse flora and fauna with distinct ecological features. For the last four decades the sanctuary has witnessed the loss of forest cover, yet the vegetation in few locations is relatively undisturbed. The current inventory was undertaken during 2019–2020 to provide a checklist of woody species from SWS under-researched earlier. The list comprises 269 species of trees, lianas and shrubs distributed in 207 genera and 68 families. The most diverse families are Fabaceae, Moraceae, Rubiaceae, Rutaceae, Lauraceae, Apocynaceae, Meliaceae, Malvaceae, Phyllanthaceae, and Anacardiaceae, representing 48% of total woody flora. The sanctuary shelters 263 native and six exotic plant species. Thirty-nine species were endemic to the Western Ghats, five species to peninsular India and one species to the Western Ghats and Andaman & Nicobar Islands. Four forest types, i.e., dry deciduous, moist deciduous, semi-evergreen, and evergreen forests, are represented in the sanctuary. Of the total species, only seven occurred in all forest types, while 111 species are exclusive to a single forest type. One-hundred-and-four taxa were assessed for the International Union for Conservation of Nature & Natural Resources (IUCN) Red List. Ten species that fall under Near Threatened, Vulnerable, and Endangered categories were encountered occasionally. The baseline data generated on plant diversity will be useful in highlighting the importance of these forests for species conservation and forest management. Such data form a cornerstone for further research. For instance, to understand the effect of invasive species and human impacts on the diversity of the region.


INTRODUCTION
India is one of the 17 mega biodiversity countries globally (Singh et al. 2015), and the Western Ghats constitute one of the 36 biodiversity hotspots. The Western Ghats are known for their exceptional biological diversity, with a high degree of endemism (Ahamedullah & Nayar 1986;Reddy et al. 2021) and a long history of field studies within and outside protected areas. Over the past few decades, there has been growing concern about the loss of biodiversity from the hotspots subjected to numerous threats (Marchese 2015), with deforestation as the primary threat; for instance the Western Ghats lost 35% of forest cover between 1920 and 2013 (Reddy et al. 2016). On the other hand, recent reviews report that annually an average of 198 new plant species are discovered from India (Reddy et al. 2021), accounting for 10% of new plant discoveries globally. But with current extinction rates we may lose many species before documentation. Furthermore, it is necessary to assess a species based on the revised IUCN Red List criteria for effective conservation as currently protected areas experience numerous threats (IUCN 2017). In this context, it is crucial to investigate underexplored areas to identify species of importance for conservation actions.
Shettihalli Wildlife Sanctuary (SWS), one of the 25 sanctuaries of the central Western Ghats in the Shivamogga district, has undergone tremendous changes in the past. The region is home to rich plant diversity with a range of forest types due to variation in rainfall, elevation, and temperature. Over the past five decades, large areas have been cleared for hydroelectric projects, dams, plantations and agricultural operations (Anonymous 2005). A four-decadal analysis  of land use and land cover changes in the region reveals that the forest vegetation has declined by 21.5% (Ramachandra et al. 2013).
A review of the literature shows that botanical explorations in the Shivamogga region are poor except for the available district flora (Ramaswamy et al. 2001), the flora of Agumbe and Tirthahalli areas (Raghavan 1970;Rao & Krishnamurthy 2021) and a few ecological inventories: plant diversity of the Kaan forest in Sagar (Gunaga et al. 2015) and ethnobotanical information of Hosanagara (Shivanna & Rajakumar 2011). Specifically, the SWS was underexplored for floristic enumeration except for the only study by Ramaswamy et al. (2001), who sampled a part of the sanctuary. Therefore, this study was undertaken to document woody flora from deciduous and evergreen forests of SWS in the central Western Ghats with a note on endemic species diversity and conservation status.

Study area
Shettihalli Wildlife Sanctuary is situated in the Malanad region of central Western Ghats, distributed over six forest ranges of three taluks in the Shivamogga district, Karnataka state, India (Figure 1). The spatial extent of SWS is 395.6 km 2 and lies between 75.167 to 75.583 longitude and 13.667 to 14.083 latitude (Anonymous 2005). It was notified in 1974 as it is of adequate ecological, faunal, floral, morphological, and zoological significance to protect wildlife and its environment. SWS experiences a tropical climate, with the mean annual precipitation that varies from 1,044 mm to 3,076 mm during the period 2010-2018 (Fick & HIjmans 2017;https://worldclim.org/). Similarly, the mean minimum and maximum temperatures range 17. 50-19.38 °C and 27.76-29.92 °C, respectively. The site receives bulk rainfall during June-October, with maximum precipitation in July. March is reported as the driest month. The landscape is characterized by undulating hills with steep terrains in the western part of the sanctuary, with elevation ranging from 850 to 1,050m. The eastern slopes' terrain is plain with an elevation that starts from 600 m and experiences low rainfall and high temperature. The sanctuary has two large open water bodies (Image 1B), and acts as a catchment basin for the Kumudvathi river. Geologically, SWS consists of various rock formations of the Archean gneisses, sandstones, and granites. Soils of SWS are ferrallitic to lateritic and mostly acidic (Bourgeon 1989). The abandoned Manganese ore quarries occur in three different locations inside the sanctuary (Image 1E). The landscape is dominated by moist deciduous forest besides semi-evergreen and evergreen forests on the hilltops of the sanctuary's western side (Anonymous 2005). The sanctuary is the host for 32 enclosures and 75 villages. The people's livelihood is mainly on the agriculture and seasonal collection of forest resources, including fuelwood.

Sampling, identification, and herbarium
A reconnaissance survey was carried out in November 2018 to understand the land use and land cover types in the landscape. Botanical explorations for woody flora (trees, lianas and shrubs) were made from Feb-Mar 2019 and Oct-Nov 2020 in the study site using a random sampling approach. Efforts were made to cover the J TT maximum area of the region. Voucher specimens were collected, methodologically processed, and identified to the species level with assistance from botanists from IFP with expertise in the Western and Eastern Ghats flora identification (Saldanha & Nicholson 1976;Saldanha 1996;Gamble & Fischer 1915-1935Ramaswamy et al. 2001). Species identification keys (Pascal & Ramesh 1987;Ramesh et al. 2010; http://www.biotik.org/), and specimens from the Herbier Institut Français de Pondichéry (HIFP) were used as reference. All mounted vouchers were deposited in the HIFP with the accession numbers (HIFP series). The current checklist follows APG IV classification, with the families listed alphabetically with their represented species (Chase et al. 2016). The species nomenclature was updated following Nayar et al. (2014). The endemic species distribution was assigned with the help of a published source (Singh et al. 2015), and conservation status was accessed from the IUCN (2021). Attempts were made to categorize species as common and rare, particularly for endemic and threatened species in the field.

Floristic diversity
This study recorded 269 woody species (trees, lianas and shrubs) belonging to 207 genera and 68 families as per the APG IV (Chase et al. 2016) classification, including three species not identified to the species level (Table 1). Of the species recorded, 269 are angiosperms and one was a gymnosperm: Gnetum edule (Gnetaceae). Dicots constituted the significant woody flora, with 263 species from 203 genera and 63 families, and the monocot contribution was six species belonging to seven genera and four families. Trees were represented by 184 (68%) species, followed by lianas with 67 (27%) and shrubs with 18 (7%) (Figure 2). The most diverse families include Fabaceae, Moraceae, Rubiaceae, Rutaceae, Lauraceae, Apocynaceae, Meliaceae, Malvaceae, Phyllanthaceae, and Anacardiaceae, which together represent 48% species and 46% genera of woody flora ( Figure 3). The top 20 species-rich families comprised 69% (208 species) of the 269 species identified from the sanctuary. The most diverse genera include Ficus (13 species); Dalbergia, Cissus, Diospyros, and Terminalia (4 species each); Artocarpus, Grewia,Holigarna,Jasminum,Litsea,Memecylon,Senna,Syzygium,and Ziziphus (3 species each). Single species represent 174 (85.3%) genera and 30 (43.5%) families. The species diversity and dominant family composition varied among the life-forms ( Table  2). Out of the 269 identified species, 263 are native to India, and six species are exotic but naturalized. Two alien invasives and Lantana camara and Chromolaena odorata (a non-woody herb to under-shrub; Image 1H), are distributed widely inside the sanctuary.

Distribution of taxa among the vegetation types
Four types of vegetation were identified from SWS, i.e., tropical dry deciduous forest (DDF), moist deciduous forest (MDF; Image 1D), semi-evergreen (SEGF; Image 1C) and evergreen forests (EGF). Taxa-wise distribution among the vegetation revealed that a maximum number of species inhabit MDF (106 species), followed by SEF (61 species), DDF (58 species), and EGF with 44 species (Table 1). Of the total species, just seven species (Ehretia canarensis, Terminalia bellirica, Dillenia pentagyna, Lagerstroemia microcarpa, Grewia tiliifolia, Ziziphus oenoplia, and Schleichera oleosa) occurred in all the forest types, while 111 species are exclusive to a single type of vegetation. The unique species varied greatly between 13 species from DDF to 27 to 39 species in    Figure 4). Categories such as Least Concern (with 79 species), Vulnerable (14), Near Threatened (six), Endangered (three), and Data Deficient (two) were listed from the study area.

Endemic distribution
From the woody flora documented from SWS, we recognized 38 species endemic to the Western Ghats, six species endemic to peninsular India and one species to the Western Ghats and Andaman & Nicobar Islands (Table 1; Images 2-5). Ninty-eight per-cent (44 species) of endemic species are reported from semi-evergreen and evergreen forest types (five and 13 species unique to SEGF and EGF, respectively). Of the 45 endemics, only two species Ehretia canarensis and Lagerstroemia microcarpa, were found in all the four vegetation types.

DISCUSSION
The study produced a comprehensive checklist of woody species of SWS, which indicates that the region is moderately diverse concerning angiosperms. The study revealed that the landscape is complex with mosaics of natural forests (dry to evergreen) to managed plantations (Teak, Eucalyptus, and Acacia species) and the human habitations surrounded by agricultural lands (Image 1G). Moist deciduous forests spread across the sanctuary, whereas semi-evergreen and evergreen forests were restricted to the western slopes of hilltops. Deciduous forests are limited to the eastern part, dominated by teak plantations.
In the present study, trees formed a major portion of the list, followed by lianas and shrubs ( Figure  2). However, this can be confirmed by quantitative ecological inventories and botanical explorations in future from the region. Our results coincide with the floristic enumeration from the Agumbe region adjacent to SWS, wherein authors reported diverse woody flora (trees -185 species; lianas -117 species; shrubs -62 species, Rao & Krishnamurthy 2021). Ramaswamy et al (2001) described 850 species of angiosperms from the Shivamogga district. The present checklist adds 92 woody species from SWS (69 trees, 16 lianas and seven shrubs; Table 2) to the district flora which were not reported earlier. This shows the floristic wealth of SWS and the importance of biodiversity documentation from unexplored areas. With an intensive exploration especially for herbs during the peak growing season, there is a scope for enriching the flora with new additions.
Species distribution pattern unveiled the adaptability of seven (2%) generalist species across all vegetation types despite variations in topographic, environmental and edaphic features. Similarly, 111 (44%) are specialists, exhibiting restricted distribution to other forest types might be due to the variation in microclimatic conditions and restricted ecological niche. In our study area, the occurrence of a large number of tree populations of valuable timber species such as Tectona grandis, Lagerstroemia microcarpa, Dalbergia latifolia and four species of Terminalia portray the economic value of the forest. Of these, except T. grandis and L. microcarpa, all others are having a higher wood specific density (>0.72 g cm-3; Agarwal 1970), which is a typical value for hardwood species (as per Nogueira et al. 2005) and obviously, such species likely to contain more carbon compared to other tropical tree species. This characterizes the landscape with considerably higher carbon sequestration potential, which deserves further investigation.
Of the 10 biogeographic zones in the country, Western Ghats harbours the maximum number of endemic species (2,327 species; Reddy et al. 2021). In our study, we found 45 species that are endemic to the Western Ghats and peninsular India. Although the number is low, few species like Lagerstroemia microcarpa, Terminalia paniculata, Flacourtia montana, Tabernaemontana alternifolia, and Cinnamomum   effort needs to be directed towards protecting these species before they become rare from the region. In the past, the sanctuary was subjected to many anthropogenic disturbances, including settlements, forest encroachment, mining and agricultural activities, and monoculture plantations. During our botanical explorations, authors have noticed dense growth of invasive alien species, i.e., Chromolaena odorata and Lantana camara, especially in the eastern parts of the sanctuary, posing a threat to the native flora. Due to the presence of 70 villages inside the sanctuary, most places are accessed by humans. Harvesting of plants for local use and grazing by livestock are evident in addition to the ongoing agricultural practices inside the sanctuary. Also, frequent forest fires are a major threat to the plant biodiversity of the region, especially around human habitations (Anonymous 2005). Considering the above facts and the plant biodiversity of the SWS with important endemic and threatened taxa coupled with distinct microclimatic conditions, the area deserves Author details: Kanda Naveen Babu is a doctoral student. Currently, he is involved in an all-India coordinated project, "Biodiversity characterization at community level in India using Earth observation data", in the central Western Ghats. Kurian Ayushi is a doctoral student and involved in the same project. Vincy K Wilson is a doctoral student who works on forest dynamics in the central Western Ghats. Narayanan Ayyappan is the principal investigator of the project, holds a PhD degree in ecology and works as a scientist. He is actively engaged in research on plant biodiversity, functional ecology and vegetation dynamics in long-term monitoring plots of Western Ghats. Narayanaswamy Parthasarathy is a professor with the expertise in forest ecology, taxonomy, and ecology of lianas. For more than three decades, he is engaged in biodiversity studies in Western Ghats, Eastern Ghats, and tropical dry evergreen forests of Coromandel coast of India Authors contributions: KNB -contributed to the fieldwork, identification, photography and manuscript writing; KA -contributed to the fieldwork, identification and specimen processing; VKW -contributed to the fieldwork, specimen processing and photography; NA -contributed to the work design, fieldwork, identification and review of the manuscript; NP -contributed to the specimen identification, guidance and review of the manuscript.