Terrestrial vertebrate and butterfly diversity of Garbhanga Landscape, Assam, India

: A study was conducted on the current status of terrestrial vertebrates and butterflies in Garbhanga Reserve Forest. Data were compiled from field surveys and secondary sources like existing literature, and citizen science databases. We found that Garbhanga is represented by 254 species of butterflies (6 families), 29 species of amphibians (7 families), 64 species of reptiles (12 families), 307 species of birds (68 families) and 31 species of mammals (19 families). In Garbhanga, amongst the studied group, two species are ‘Critically Endangered’ (CR), six species are ‘Endangered’ (EN), 14 species are ‘Vulnerable’ (VU), eight species are ‘Near Threatened’ (NT), eight species are ‘Data Deficient’ (DD), 411 species are ‘Least Concern’ (LC), and 236 species are not assessed (denoted by blank space). This shows a huge gap in research and status evaluation of understudied species. This in turn also provides further research opportunities on the lesser known species.


INTRODUCTION
Documentation of biodiversity is essential for effective conservation and management efforts, as it provides a comprehensive understanding of the species and habitats that are present in an area. It helps to identify the species and habitats that are most in need of protection. This information can be used to prioritize conservation efforts and support the development of targeted management plans (Vane-Wright et al. 1991). Documentation of biodiversity can support efforts to monitor changes in species populations and the health of ecosystems over time. This information can help to detect emerging threats to biodiversity, such as the spread of invasive species, disease outbreaks, or changes in land use patterns (Sala et al. 2000). The state of Assam is the most urbanized state of northeastern India with a population exceeding 31 million (Saikia 2019). The state has an area of 78,438 km 2 , which comprises of 2.39% of the geographic area of India and is a part of Indo Burma biodiversity hotspot. According to the Forest Survey of India (2021) report, the total recorded forest area of the state is 28,312 km 2 which is 36.09% of the geographic area of the state and is greater than the average forested area of the country which stands at 21.71%. The forest type mostly comprises of tropical wet evergreen, tropical semi evergreen, tropical moist deciduous, subtropical broad-leaved hill, sub-tropical pine, littoral, and swamps. A total of 3,513 wetlands exist within the state spreading across an area of 1,012.32 km 2 (Assam Forest Department 2011-12). The faunal composition of the region is particularly interesting as it is located at a confluence of Indo-Chinese, Indo-Malayan, and Indian biogeographic regions (Ahmed et al. 2009). Assam has more than 300 reserve forests with Garbhanga being one of the largest reserve forests (Assam Forest Department 2011-12). Garbhanga Reserve Forest is situated in the north of the Guwahati city of Assam and spreads across an area of 114.6 km 2 . The reserve forest is connected to Rani Reserve Forest which has an area of 437.26 km 2 and is often referred to as Rani-Garbhanga landscape (Devi et al. 2012). Together, they constitute the biggest network of reserve forested areas of Assam. Garbhanga Reserve Forest includes undulating hill ranges with altitude ranging 80-670 m. Recently, through an Assam Gazette notification (No.FRW.3/2022/44) dated 7 April 2022, an area of 117 km 2 within the Garbhanga Reserve Forest has been proposed for a wildlife sanctuary.
Many hill streams flow within the reserve forest. The main river flowing through the reserve forest is the Basistha River which finally drains into Deeporbeel Wildlife Sanctuary and Ramsar site. The forest type mostly constitutes of moist deciduous type which accounts for about 75% of the forest type with Sal Shorea robusta being the predominant tree species. Secondary forest constitutes mainly of scrub forest and bamboo accounting for 10% and 7%, respectively. The soil type of the reserve forest is gravelly on crests and upper slopes, deep red and clayey in the foot hills, and alluvial lower down (Devi et al. 2012).
Due to the topology, forest type and climatic condition, Garbhanga is home to a wide variety of biodiversity. Lahkar et al. ( 2010) recorded 128 species of birds; Modak et al. (2018) recorded 54 species of butterflies; Barua et al. (2004) recorded 29 species and subspecies of swallowtail butterflies from Garbhanga. Herein we present a detailed checklist of butterflies, amphibians, reptiles, birds, and mammals within the notified area of Garbhanga wildlife sanctuary (proposed).

Study Area
The  (Champion & Seth 1968). Once known to be the original habitat of Sal species, excessive logging led it to be replaced by secondary bamboo brakes (Champion & Seth 1968 (Barua 2007). The forest also borders on the northwestern side with Deeporbeel Wildlfe Sanctuary.

Data collection for checklist
The data for all the taxa groups were compiled from  (Crump & Scott 1994). Secondary data were collected from research articles (Baruah 2004;Lahkar et al. 2010;Modak et al. 2018;Purkayastha 2018;Bohra & Purkayastha 2021) and citizen science database (eBird 2022) which has bird observation information since 2008 to recent times. The taxa groups were then categorized as per the IUCN Red List criteria.

Spatial analyses/ mapping:
Elevation gradient and stream network were derived using the Hydrology tool in Arc Map 10.4 using Carto DEM Version-3 R1 ( Figure 1A). We found that elevation gradient ranges 0-594 m. NDVI was calculated using Sentinel 2A data in Arc Map 10.4 ( Figure 1B). Elevation and stream network map was generated using data from CartoDEM satellite (https://bhuvan-app3.nrsc.gov.in).

Butterflies
A total of 254 species of butterflies representing six families were recorded from the study site. Only 30 species are categorized under different categories as per the IUCN Red List including Common Duffer Discophora sondaica which is considered as 'Near Threatened' while all the other species are not assessed ( Figure 2, Table  1). Family Nymphalidae was observed to be the most dominant family, accounting for 100 species from the

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study area.

Amphibia
We recorded 29 species of amphibians representing two orders (Anura and Gymnophiona) and seven families. The family Dicroglossidae was found to be the most species rich represented by eight species whereas the family Bufonidae was represented by just a single species. According to the IUCN Red List, 19 species were 'Least Concern', five species were 'Data Deficient', one 'Vulnerable', and four species are not assessed ( Figure  3, Table 2).

Reptilia
We recorded 64 species of reptiles representing three orders and 12 families. Lizards were represented by 21 species, snakes by 39 species and turtles by four species. Amongst lizards, family Gekkonidae was found to be dominant and had nine representative species. Colubridae was the most species rich family among snakes accounting for 29 species. According to the IUCN redlist, three species are 'Endangered', four species were 'Vulnerable', two species were 'Near Threatened', one species was 'Data Deficient', 49 species were 'Least Concern', and five species are not assessed ( Figure 3, Table 3).

Birds
We recorded 307 species of birds belonging to 68 families from the study site. Among them, the family Muscicapidae was found to be dominating in terms of species richness represented by 34 species. According to the IUCN Red List there are one 'Critically Endangered' species, one 'Endangered' species, four 'Vulnerable' species, five 'Near Threatened' species, 293 'Least Concern' species and three species are yet to be assessed ( Figure 3, Table 4).

Mammals
Garbhanga harbours 31 species of mammals belonging to 19 families. According to the IUCN Red List, one species is 'Critically Endangered', two species are 'Endangered', five species are 'Vulnerable', one species is 'Near Threatened', the remaining 22 species are 'Least Concern' (Figure 3, Table 5).

DISCUSSION
The data reported above indicate that the Garbhanga landscape is extremey rich in biodiversity and merits more protection through a legal status. It is noteworthy that vide notification number FRW.3/44. dated 28 march 2022, a preliminary notification was passed in The Assam Gazette dated 7 April 2022 showing the intent of the Governor of Assam to declare an area of 117 km 2 of Garbhanga as a wildlife sanctuary. This step will help enhance protection and conservation of the   forest which is in the vicinity of the biggest metropolis of northeastern India, the Guwahati City. The forest is under tremendous pressure from the anthropogenic activities such as stone mining, illegal felling of trees, and unsustainable non-timber forest products collection. Also, the busy concrete road connecting the forest with Meghalaya adds to the threats (Lahkar et al. 2010). The dynamite blast in the stone quarries is having a negative impact on its biodiversity (Purkayastha 2018). All these factors disturb the ecological functioning of the area. Recent discovery of a new species of Bent-toed Gecko Cyrtodactylus urbanus from the fringes of Garbhanga (Purkayastha et al. 2020), new locality record for Yellow-throated Marten (Kakati et al. 2021) along with the findings of 254 species of butterflies, 29 species of amphibians, 64 species of reptiles, 307 species of birds and 31 species of mammals stress on the importance of the landscape in terms of its rich biodiversity. Garbhanga is also a favorable elephant habitat, supporting a good population, connected by corridors to Meghalaya (Borah et al. 2004).
Many species of different taxa groups in Garbhanga are of conservation concerns. 3% (3.2%) of all the recorded species were found to be threatened according to IUCN red list. Also 34% (34.5%) of the species are yet to be evaluated highlighting the huge gap in research J TT

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