Rapid multi-taxa assessment around Dhamapur Lake (Sindhudurg, Maharashtra, India) using citizen science reveals significant odonate records

In the present work, we discuss the results of a four-day long rapid survey around Dhamapur Lake and surrounding freshwater habitats in the Sindhudurg District of Maharashtra through public participation. In total, 61 odonates, 51 butterflies, 17 species of amphibians and reptiles, 90 birds, and four mammals are documented. Our observations taken over a brief time reflect the importance of citizen science in documenting local biodiversity. We report involvement of citizen scientists in recovering significant odonate records for the state.


INTRODUCTION
The indeterminate exploitation of the natural resources by humans has caused considerable alterations in the ecosystem functioning and biodiversity loss through urbanization, habitat destruction, habitat modification, and degradation of vital freshwater resources (Gleick et al. 2001;McKinney 2002;Diaz et al. 2006;Dudgeon et al. 2006). Despite the current body of knowledge of environmental degradation, several regions remain less explored in terms of data on biodiversity. The lack of knowledge on biodiversity hampers the decision making at policy level and hence considered as one of the global priorities when forming conservation frameworks (Meyer et al. 2015;Sorte & Somveille 2020). In recent years, citizen science has proved to be a beneficial tool in collecting biodiversity data through people's participation (Theobald et al. 2015;Chandler et al. 2017;Mckinley et al. 2017). It is used for research, to understand distribution and possible threats to multiple taxa like insects, amphibians, birds, and mammals (Kolby 2015;Forrester et al. 2017;Zapponi et al. 2017;Sorte & Somveille 2020). In India, the practice of citizen science has proved as a useful tool for biodiversity documentation at finer spatial scale (Badrinath 2015;Seshadri & Gururaja 2015;SoIB 2020).
DragonflySouthAsia (DSA), a part of DiversityIndia (http://diversityindia.org/), is a citizen science network of Odonata (dragonflies and damselflies) watchers and researchers from the Indian subcontinent (https:// dragonflyindmeet.wordpress.com/). DSA has been actively involved in conservation outreach and research, popularizing odonatology and freshwater conservation through meets and workshops every year since 2014 (Andrew et al. 2015;Dawn & Roy 2017;, and facilitating collaborative research (Mujumdar et al. 2018). In the current survey, we used a combination of rapid multi-taxa assessment and citizen science to document biodiversity in Dhamapur Lake area taking odonates as target taxa. Here, we demonstrate that peoples' participation in science can provide reliable biodiversity data in a very short period of time and help highlight the potential of the lake to support the urgency to protect it.

Study area
Sindhudurg District, situated at the southernmost tip of Maharashtra, is one of the biodiversity rich areas of the state and includes parts of northern Western Ghats, locally known as Sahyadri Hill ranges. Dhamapur Lake (16. 033°N & 73.593°E; 22m) is located in the Malvan Tehsil of Sindhudurg District (Figure 1, Image 1). The climate of Malvan Tehsil remains hot and humid throughout the year having an annual average temperature 27.1°C and average annual precipitation of 2,865mm (Malvan summary 2020).
The lake is a 400 years old human-made lake with an area of 22 hectares. It provides water to Malvan City (TERI 2013). The surrounding villages Dhamapur and Walvali depend on its water for domestic use and irrigation purposes. The forest around the lake is moist deciduous and categorised as reserve forest. Streams having varying canopy cover, flow along one side of the lake (Image 3), while the other side is surrounded by marshes and paddy fields (Image 2).

Survey sites
We surveyed various freshwater habitats like lakes, ponds, wells, and streams around Dhamapur Village as our focal taxon was odonates. We also surveyed the natural vegetation, paddy-fields and forest patches around these habitats. Details of the study sites are given in Table 1 (Images 2-6).

Data collection
The 6 th DragonflySouthAsia meet was conducted during 10-13 October 2019 wherein a total of 25 people participated from India and Sri Lanka. A few members of Syamantak, a local community working towards conservation of wetlands in the Sindhudurg area (http:// syamantak.cfsites.org/), also took part.
On all the four days, we opportunistically surveyed the sites for rapid assessment of selective invertebrates and vertebrates. Rapid multi-taxa assessments are used to yield quick yet reliable results. These are cost-effective, useful to make inventories of the local biodiversity, and the information obtained in terms of species richness can be used potentially to represent the community structure (Oliver & Beattie 1993, 1996. We used citizen science model for data collection and to document the maximum number of species (Chandler et al. 2017). The process involves participation in the survey by volunteers with little or no expertise on the taxa whose observations were verified by the experts later on.
The participants were split into four different groups, each containing six to seven members, to cover different habitats surrounding the lake (Image 2 & 3). They were trained in using iNaturalist app (https://www. Identification of odonates was based on field guides (Subramanian 2009) and taxonomy monographs (Fraser 1933(Fraser , 1934(Fraser , 1936. For identification, we referred to Bhakare & Ogale (2018) for butterflies, Grimmett et al. (2011) for birds, and Menon (2014) for mammals. Amphibians and reptiles were identified with multiple references like Daniel (2002), Whitaker & Captain (2004), Gururaja (2012), Padhye et al. (2015), and Pal et al. (2018). We documented most of the species in the field using point-and-shoot digital as well as SLR cameras. In case of ambiguity, we took photographs of the specimens on the field and later identified them to the species level with the help of field guides and taxa experts, especially in the case of amphibians and reptiles.

Comments on significant records of odonates
Following odonates observed at Thakurwadi Lake on 12 October 2019 are significant records considering their current known geographical distributions. The lake is filled with emergent and submergent aquatic vegetation including members of family Nymphaeaceae (Image 4).

Lestes praemorsus decipiens Kirby, 1894
A pair was observed in the marshy area of the lake. The male was identified as Lestes praemorsus on the basis of characters like thorax with greenish antehumeral stirpes, crenulate on the outer sides; segment nine with dorso-lateral blue marking; blunt and curved cerci with whitish hairs and paraprocts blackish, short with white hairs at the tip (Image 10). The female looked similar to the male with profound thoracic antehumeral stripes. Anal appendages were whitish, short, and pointed (Image 11). The species is distributed from western India to Assam (Fraser 1933), Andaman Islands and across the northern parts of the country and consist of two subspecies L. praemorsus sikkima Fraser, 1929and L. praemorsus decipiens Kirby, 1893(Prasad & Varshney 1995Dow & Sharma 2020). L.p. sikkima is confined to Sikkim in northeastern India and is distinguished by having a metallic posthumeral stripe (Fraser 1933). The male specimen observed at the lake lacks any metallic posthumeral markings (Image 12), thus it is concluded to be representing the widespread subspecies L.p. dicipiens. It should, however, also be noted that the taxonomic status of the subspecies of L. praemorsus is insufficiently resolved (Kosterin 2019 J TT species in September 2017 at a natural pond with aquatic weeds in Vimleshwar Village of the district. Considering the distribution in the mentioned references and citizen science portals (Anonymous 2020a), we note that these are the first confirmed records of the subspecies from Maharashtra.

Platylestes cf. platystylus
A single female individual sighted at the lake seems to be closer to Platylestes platystylus (Rambur, 1842) based on the pterostigma (quadrate as opposite to elongate in Lestes spp.) and thoracic markings (presence of black spots on each side) (Image 13). We did not collect the specimen hence species level identification was not confirmed. We treat our record as Platylestes cf. platystylus. The species P. platystylus has distribution in West Bengal in India (Fraser 1933;Prasad & Varshney 1995;Sharma 2010). It is also reported from Tripura and Kerala on citizen science portals (Anonymous 2020b; https://www.inaturalist.org/observations?place_ id=6681&taxon_id=109709).
Rison & Chandran (2020) recorded the species from few localities in Kerala recently. During present study, the female was seen curling abdomen on an emergent aquatic plant, indicating probable attempt at egg-laying.

Pseudagrion malabaricum Fraser, 1924
Pseudagrion malabaricum was first reported from Maharashtra State by Tiple et al. (2013) in the Vidarbha region. Subsequently, this species has also been reported from Devgad Taluka and Chaukul Village in Sindhudurg District (Anonymous 2020c). During the present survey, several adults were observed among the reeds and grassy aquatic vegetation near the lake edge (Image 14). The species was identified based on the cerci being shorter than abdomen segment 10 and not bifid at apex (Image 15). The only other Pseudagrion species recorded in the habitat, P. microcephalum, has bifid cerci clearly longer than the segment 10 while the morphologically similar species P. australasiae has cerci bifid at apex as seen in profile (Fraser 1933).

Gynacantha cf. khasiaca
A single male individual was observed in the vegetation surrounding the lake. The specimen was recognised separate from the other Gynacantha spp. recorded during the study and showed similar characters to those of Gynacantha khasiaca MacLachlan, 1896 i.e. paraproct longer than half of the length of cerci (Image 18) and two lateral brownish stripes on the greenish thorax (Image 19). G. khasiaca is distributed in West Bengal, Assam and Khasi hills in Meghalaya in India (Fraser 1936). Few studies further add the southernmost distribution of the species to West Bengal (Mitra 2002;Payra et al. 2017). We confirm the observed specimen as Gynacantha cf. khasiaca owing to confirmation of the mentioned limited characters as we did not collect the specimen. It is an interesting opportunistic record from the western India considering its affinity to G. khasiaca with the known distribution range in northeastern parts of the country (Mitra et al. 2010). It requires detailed study of the specimen further to confirm its identity.

Indothemis limbata sita Campion, 1923
Indothemis limbata was described as Trithemis limbata Selys, 1891 based on specimens from Myanmar and Malay Peninsula. A different form of the species was described as I. limbata sita from Sri Lanka, based on the wing venation and markings (Campion 1923). Later studies considered I. limbata limbata to be restricted to Myanmar and southeastern Asia and I. limbata sita to be restricted to the western India and Sri Lanka barring one record from Odisha (Fraser 1936;Prasad & Varshney 1995). Babu et al. (2009) (Anonymous 2020d) and Uttara Kannada, Karnataka (https://www.facebook.com/photo/?fbid=7 07419235973335&set=gm.740960425953503). These studies show that there has been a discrepancy on the identity and distribution of both the subspecies. The new record of I. limbata limbata from Maharashtra needs to be confirmed by re-examining the specimens and comparing with the holotypes since all the other records of the subspecies are from Odisha and northeastern parts India and the paper didn't include any illustration or image of the specimens studied.
Present records from the lake show the presence of at least one adult (Image 20) and one sub-adult male (abdomen with yellowish markings) (Image 21). We confirm the record as Indothemis limbata sita based on characters of the adult male such as hyaline wing apices and 10-1/2 antenodal nervures in the forewing (apices bordered as blackish-brown and 11-1/2 -12-1/2 antenodal nervures in I. limbata limbata). At species level I. limbata is distinguished from the congeneric species I. carnatica (Fabricius, 1798) by black body with black anal appendages and base of hindwing with extensive brown marking as opposite to violaceous body J TT

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DISCUSSION
Inventorying and monitoring biodiversity at a regional scale is essential as it provides vital information on the occurrence and distribution of local diversity, and their associations with local habitat. A study by Kunte et al. (1999) recommended biodiversity surveys at a local level encompassing taxa from diverse groups and not just flagship vertebrate species like birds and mammals. It further states that building a network of long-term biodiversity monitoring projects with an understanding of landscape elements (e.g., vegetation types, microhabitats requirements of particular taxa) in ecologically sensitive areas such as the Western Ghats is important.
The current study dwells on two important aspects discussed as following -

a) Role of citizen science in biodiversity documentation
The very key aspect of citizen science is public engagement in data collection through which they can connect with nature and make a positive contribution towards the environment. It acts as a bridge between researchers and the local community, including the stakeholders. The participants actively participated in the current survey and documented different taxa of the study area with increased interest towards local biodiversity. Their effort resulted in the multi-taxa checklist of Dhamapur Lake and surroundings and also added two subspecies to the state Odonata checklist. They also uploaded their observations on the online database of iNaturalist that served the purpose of data sharing on a broader platform.

b) Conservation implications of Dhamapur Lake and surroundings
Among the odonates, presence of the species Platylestes cf. platystylus and Gynacantha cf. khasiaca, possible new records to the state (Tiple & Koparde 2015; Koparde et al. 2020), highlights the potential of the lakes for more systematic Odonata surveys in the future. Habitats around Dhamapur Lake support a rich and diverse fauna. The scheduled butterflies like D. bisaltide, P. sylvia, and C. lepidea and the key-stone bird species such as A. coronatus and B. bicornis are indicator species inhabiting dense moist forests. We observed a colour aberrant individual of Psilopogon viridis (Boddaert, 1783) during the survey (Image 46). We based the species identification, in the absence of prominent cheek and head coloration, on size and iris skin colour (black as in P. viridis). We speculate that the bird was either a leucistic or ino individual given features such as normal eye pigmentation, iris skin and beak colour (Grouw 2006;Koparde et al. 2014). Habitats around Dhamapur Lake are also known to harbour a large variety of animals including Lutrogale perspicillata (I. Geoffroy Saint-Hilaire, 1826) -Smooth Coated Otter, a Vulnerable species according to IUCN. The biodiversity action plan prepared for Sindhudurg and Malvan districts mentions the lake as a large wetland and as a unique feature of Malvan Tehsil, further mentioning that the lake has the potential to be developed as a Ramsar site, however, J TT biodiversity has to be studied (TERI 2013).
Biodiversity studies have been focused at certain locations in Sindhudurg District. Places like Amboli, a hill station in Sawantwadi Tehsil, attracts many nature enthusiasts and tourists every year. Explorations by the researchers have resulted in a number of scientific publications (Bhakare & Ogale 2018;Satose et al. 2018;Rao et al. 2019) and new species (Vogel & Rooijen 2011;Sayyed et al. 2018;Chaitanya et al. 2019) from this area. There are hardly any long-term monitoring studies in this area facing high tourism pressure.
Current work done over a period of just four days revealed some interesting faunal records, especially for odonates, birds, and mammals that tried to fill the knowledge gap on the biodiversity information of the district. The findings, though primary, form the base for future monitoring and conservation of the Dhamapur Lake area. We recommend systematic biodiversity surveys in this underexplored but potentially biodiversity rich area for conservation of local freshwater ecosystems such as the streams originating from the lake, and important rivers such as Karli River. Data collected on the local biodiversity can be used to target local students for awareness programmes and to promote sustainable tourism activities without disturbing the integrity of the lake and nearby forest, in order to avail the resources in the long run.
Author details: Neha Mujumdarworking as scientist at Bombay Natural History Society, Mumbai. She has documented diversity and ecological aspects of butterflies and odonates in the Western Ghats. She is one of the admins of DrgaonflySouthAsia. Website: https://dragonflysouthasia.wordpress. com/. Dattaprasad Sawant -a doctor by profession and graduated from GMC JJ Hospital, Mumbai. He is pursuing MD in Preventive and Social Medicine in Seth GSMC and KEM Hospital, Mumbai. He is documenting Lepidoptera and Odonata diversity of Konkan region. He has described two new Odonata species from Maharashtra with Shantanu Joshi. Amila Prasanna Sumanapala -a Sri Lankan field researcher primarily studying Odonata diversity, ecology, biogeography and conservation. Also interested in arthropods and birds. Currently pursuing M.Phil on Odonata at University of Colombo, Sri Lanka. Parag Rangnekar -researcher and ecologist based in Goa with interest in avian, butterfly and odonate diversity and ecology. He has described two new species of dragonflies from the State. He operates various communitybased ecotourism initiatives. Dr. Pankaj Koparde is an evolutionary ecologist, working as an assistant professor at MIT World Peace University. He is interested in science-driven conservation research and outreach. He is one of the admins of DrgaonflySouthAsia. website: https:// www.chaturullu.in/ Author contribution: NM collected data in the field on butterflies, odonates and herps, contributed images, prepared checklists and wrote the manuscript. DS collected data on butterflies and odonates in the field, helped in their identification and manuscript editing, and contributed images. AS collected data in the field on butterflies, odonates, herps and birds, contributed images, helped in manuscript editing. PR collected data in the field on butterflies, odonates and birds, prepared checklists, helped in manuscript editing.
PK conceptualized the idea and organized the field data collection drive, collected data in the field on odonates and birds, and reviewed manuscript draft.