A preliminary assessment of Odonata (dragonflies & damselflies) across an elevation gradient – insights from Shiwaliks to Alpines, northwestern

: Understanding the species distribution and richness along an environmental gradient helps identify hotspots and prioritize conservation efforts at landscape scale. This is more effective for the species that are indicators of environmental change, such as odonates. As the information about the distribution of this group of insects is scarce in Jammu & Kashmir, their documentation assumes a greater significance. Here, we present a checklist of odonate species from 23 sites across diverse landscapes in subtropical, temperate, and alpine ecosystems over an elevational gradient of 3,700 m in Jammu division. We recorded 63 species from 39 genera and 11 families, four Anisoptera and seven Zygoptera. The most represented families were Libellulidae (15 genera & 29 species) and Coenagrionidae (five genera & 10 species). The preliminary surveys resulted in addition of 24 new species to the Odanata fauna of Jammu & Kashmir, including three new to the northwestern Himalaya. The study underlines that even opportunistic records are useful in understanding the distribution range and delineating the potential habitats of odonates. The study calls for intensive odonate surveys to better understand their distribution and ecology in hitherto less explored region in the northwestern Himalaya.


INTRODUCTION
The Himalayan Odonata fauna comprises of 257 species in 112 genera and 18 families with 34 species endemic to the Himalayas (Subramaniam & Babu 2018). Though well-documented in the neighbouring states of Himachal Pradesh and Uttarakhand, the information on the distribution of Odonata in Jammu & Kashmir is scanty. The earlier accounts of Odonata from Jammu & Kashmir dates back to the records of Abott (Calvert 1899), Fraser (1933Fraser ( , 1934Fraser ( , 1936 followed by a few checklists (Singh & Baijal 1954;Asahina 1978;Kumar & Prasad 1981;Carfi et al. 1983;Kumar 1983;Lahiri & Das 1991;Dar et al. 2002;Mitra 2003). Recently, a few surveys have been conducted to describe the diversity and distribution of odonates of Jammu & Kashmir Sheikh et al. 2020;Riyaz & Sivasankaran 2021;Quereshi et al. 2022;Kumar et al. 2022). Singh (2022)  Geographically, the union territory of Jammu & Kashmir comprises two regions, Jammu & Kashmir characterized by five distinct physiographic units.
The Jammu region of Jammu & Kashmir offers a wide range of habitats from the alluvial plains of the Ravi and Chenab rivers in the south to the moderately elevated Shiwaliks, Pir-Panjal, and Greater Himalaya northwards, bordering Kashmir in the north and Ladakh in the north-east. Documenting odonate fauna from such regions becomes important as it helps fill the knowledge gap about distribution of species, which may have conservation implications. To gain a better understanding of the spatial distribution of odonates in the region, we conducted preliminary surveys in seasonal and perennial water bodies in parts of alluvial plains, sub-tropics, lesser, and the Greater Himalaya spanning a vast elevational gradient ranging from 260-3,960 m. The baseline information obtained on the abundance and distribution of 63 species of odonates for the region will be useful for monitoring the health of aquatic ecosystems on spatial and temporal scales.

METHODS
We sampled the adult dragonflies in 23 stations: eleven in the subtropics, nine in temperate, and three in alpine habitats in Rajouri, Jammu, Udhampur, Kathua, Figure 1. The sampling sites in three climatic zones (subtropical, subtemperate / temperate and alpine) in the study area. The outer plains and urban setups lie in the subtropical zone, a part of Jammu Shiwaliks.

Jammu & Kashmir
Odonates across an elevation gradient in Himalaya * Geo co-ordinates and elevation taken as the centre point of each 1.5-2 km 2 grids sampled.

J TT
counted for abundance and density estimates, however, the frequency of sightings was taken into account for computing the relative frequency. The odonates were categorized as very common (sighted during 75-100 % of the sampling), common (sighted between 50-75 % times), occasional (observed between 25-50 %), and rare (sighted below 25% times) following Adarsh et al. (2014). All the field visits were conducted between 1000 h to 1200 h, when the adult odonates are most active. The individual odonates were photographed and identified to the species level referring to the field guides (Subramanian 2005(Subramanian , 2009Kiran & Raju 2013;Singh 2022) and curated online platforms like Odonata of India website (https://www.indianodonata.org/). No specimens were, however, collected during the surveys. The species have been enlisted following the systematic arrangement and taxonomy of  and Kalkman et al (2020).

RESULTS
A total of 63 odonates (40 dragonflies and 23 damselflies) were recorded from the study area. These belonged to 39 genera and 11 families, four anisopterans and seven zygopterans (Table 2, Figure  2, Images 1-63). In terms of habitat sharing, 50 species were exclusively found to be associated with one of the three ecosystems studied, indicating their limited geographical distribution. The sub-tropical ecosystems harboured high richness (SR = 46) accounting for 73% of the total, followed by temperate (SR = 28, 43%) and alpine (SR = 5, 8%). Fourteen species were found to be common across subtropical and temperate ecosystems, whereas temperate and alpine shared only two species, Cordulegaster brevistigma and Orthetrum internum. Families Calopterygidae, Chlorocyphidae, Chlorocyphidae, and Platycnemididae were confined to subtropical habitats, while Gomphidae, Libellulidae, Coenagrionidae, Euphaeidae, Lestidae, and Synlestidae exhibited affinities for both sub-tropical and temperate climate (Figure 3).
The occurrence data (relative frequency) during the study period shows that 48 species (76%) belonged to occasional and rare (n = 24, each) category. Eleven species were found common and four very common. Orthetrum pruinosum, O. triangulare, and Sympetrum commixtum among the Anisoptera and Amphiallagma parvum among the Zygoptera were the most commonly encountered species during the current sampling. In all, 60 species are classified as 'Least Concern' by the IUCN, while three species have not yet been evaluated for their threat status (Table 2). Families Aeshnidae and Libellulidae are found in all three climatic zones, occupying a greater elevational range than other Anisoptera families (Figure 3). Family Cordulegastridae comprising a solitary taxon Cordulegaster brevistigma was restricted to temperate and alpine zones, whilst members of the family Gomphidae were restricted to subtropical and temperate regions. Most of   (Table 2).

DISCUSSION
The Anisoptera families Libellulidae (29 species) and Aeshnidae & Gomphidae (5 species, each) accounted for nearly 62% of all species observed during the current sampling. Four families (Cordulegastridae, Calopterygidae, Lestidae, and Synlestidae) and 24 genera were monotypic indicating their restricted distribution in the region. Libellulidae and Gomphidae are welldistributed (Subramanian 2005) Anisoptera across the Indian subcontinent. The widespread dispersal and distribution may be attributed to the larger body size of species in these families (Dalzochio et al. 2011). The habitat heterogeneity and varying microclimatic regime sustain a high species richness and diversity (Cramer & Willig 2005;Storch et al. 2023) among different groups of animals. High species richness has been recorded from the small water bodies like rivulets, and streams as they create conducive microhabitats suitable for their survival as observed by Arunima & Nameer (2021),   , and Thakuria & Kalita (2021) as well. Key conditions for many species include shading around water bodies, specific vegetation structure for breeding and oviposition or nymphal microhabitat availability (Rantala et al. 2004;Cheri & Finn 2023). Subtropical ecosystems supported more odonates than temperate and alpine habitats, indicating a declining trend in species richness with increasing elevation as reported in other insect groups (Vetaas et al. 2019, Fontana et al. 2020Dewan et al. 2022). No damselfly was found above 2,200 m in the current sampling effort (Figure 3). This does not, however, elude their presence in sub-alpine and alpine climate zones, as these landscapes were not visited as frequently as subtropical and temperate ones were.
Singh ( Recent studies conducted in the Himalaya reveals that Odonata fauna of the region is threatened due to habitat destruction, agricultural expansion, pesticides, tourism, urban and industrial pollution De et al. 2021) and this holds true for the study area. Aquatic ecosystems are spatially and temporally constrained (De et al. 2021), and the sites of current explorations are found in close proximity to human settlements, roads and highways making them vulnerable to management activities that threaten the existence of aquatic biodiversity including odonates. Most roadside ditches are being destroyed by road expansions, ponds are being encroached upon for land reclamation, and rivers and streams are being exposed to sand extraction and increased pollutant loads.
In terms of the occurrence data, 48 species belonged to occasional and rare categories. Arunima & Nameer (2021) in their observations recorded a moderately high number of occasional and rare species. Interestingly, all taxa found during the sampling figure in the least concern category of conservation (IUCN 2023) indicating a stable worldwide population. The study though preliminary with limited area coverage and ecological scope has unveiled vital information regarding the distribution of the observed odonate species in the heterogenous landscapes of northwestern Himalaya. Though the current observations on the Odonata do not necessarily provide a complete checklist for the region, they do add to the knowledge of the insect fauna of the Union Territory of Jammu & Kashmir. More systematic research on odonate assemblages and seasonality is needed to describe the ecology and biomonitoring of their habitats in the region as macroinvertebrates are standard bioindicators of freshwater ecosystems (Barbour et al. 1999).