A large number of animal and plant species are restricted only to wetlands, their survival depending totally on the existence of these habitats. The Insects represent over half of the global biodiversity in terms of species numbers. Among the different orders of insects, the fascinating butterflies belongs to the order Lepidoptera, in that about 17,500 species of butterfly recorded so far throughout the world, of which about 1,379 species of butterfly are known from India (Evans, 1932; Talbot, 1939; Wynter-Blyth, 1957; Haribal, 1992; Kunte, 2000; Kehimkar, 2008; Cotton et al., 2015; Sondhi & Kunte 2018; Singh, 2022; Singh et al., 2024). Butterflies have fascinated human imagination, creativity, valuable pollinators, one of the important food chain components of the birds, reptiles, spiders and predatory insects, also good indicators of environmental quality as they are sensitive to changes in the environment. 

Perusal of literature reveals that the various workers contributed and documented their work on the study of butterflies in the different parts of India i.e. de Niceville (1886, 1890); Moore (1890-1903); Marshall & de Niceville (1882); Swinhoe (1893, 1905-1912); Bingham (1905, 1907); Evans (1932); Talbot (1939, 1947); Wynter-Blyth (1957); Cantlie (1962), Varshney (1993, 1994, 1997);  Arora (1994, 1995 & 1997);  Gaonkar (1996); Haribal (1998), Heppner (1998), Gunathilagaraj et al. (1998, 2000); Kunte (2000); Joshi and Joshi (2003); Gupta and Mondal (2005); Sharma et al. (2006); Kumar et al. (2007 a&b); Maulik, (2010); Tyagi et al., (2011); Smetacek (2012);  Arya and Dayakrishna (2014); Singh and Sondhi (2016); Singh (2022); Bisht et al., (2023); Chandra et al., (2023); Singh, et al. (2024) etc., but none of the work on study of butterflies was documented from the study area. Therefore, the present studies made a modest attempt to explore the existing diversity of Butterflies of Asan Conservation Reserve and RAMSAR site, District Dehradun, Uttarakhand, India.

The extensive studies on butterflies has been done by visiting in all the seasons of the year in and around the study area Asan Conservation Reserve and RAMSAR site, District Dehradun, Uttarakhand, India during September, 2021 to October, 2024. The study area having coordinates 30°26′09″N, 77°39′56″E, is a small wetland spread over an area of 444.4 hectare stretch of Asan river running down to its confluence with the Yamuna river. The Asan Wetland, also known as Dhalipur Lake or Asan Barrage Bird Sanctuary was established in 1967, further declared as Asan Conservation Reserve in 2005 and as First RAMSAR site of Uttarakhand in 2020, it is also famous as tourist attraction for observation of migratory waterbirds from October to March every year. A large number of animal and plant species are restricted only to wetlands, their survival depending totally on the existence of this habitats. 

To explore the species diversity the study area Asan Conservation Reserve and RAMSAR site was divided into four Sectors i.e. Sector-I (around vegetation near Asan Barrage); Sector-II (around wetland vegetation Opposite end Asan Barrage); Sector-III (around vegetation near Asan river) and Sector-IV (around vegetation near Yamuna river) (Figs. a-d). The unidentified butterfly species were caught in the field by using Insect net and after taking photographs, observation and identification of the species with the help of field guides, the live individuals were released in the habitat. In the field observations were also made on the bahaviour, life history of different species of Butterflies, taken photogrphs of species using Nikon DSLR7000 camera with closeup attachments, collected very few selected repersentatives of unidentified individuals of butterflies species, transferred them into insect collection paper packs and were brought to the laboratory. Also studied the earlier survey collection of butterflies preserved in National Zoological Collections of Zoological Survey of India, Northern Regional Centre, Dehradun. The identification in the field and of the collected preserved specimens was carried out using identification keys provided by Bingham (1905, 1907); Evans (1932); Talbot (1939, 1947); Wynter-Blyth (1957), Cantlie (1962); Varshney (1993, 1994, 1997);  Arora (1994, 1995 & 1997);  Haribal (1998) etc. 

Fig. a-d.  A glimpse of study area Asan Conservation Reserve, Uttarakhand.

The identification and synthesis of studies resulted into New record of about 43 species of butterflies from the study area, in that Nymphalidae is the dominant family having 22 species followed by Pieridae 13 species, Lycaenidae 06 species and least by Papilionidae 02 species (Table 1). This aligns with global trends, as Nymphalidae is known to be the largest and most ecologically diverse butterfly family, occupying a wide range of habitats and exhibiting varied life history strategies. As the study area was divided into four sectors and recorded maximum number of 43 species in the Sector-II (in wetland vegetation opposite end Asan Barrage), followed by 26 species in Sector-I (vegetation around Asan Barrage), 23 species in Sector-III (vegetation around Asan River) and least 17 species in Sector-IV (vegetation around Yamuna river), which indicates that maximum species of Butterflies prefers Sector-II study area having Wetland vegetation as suitable habitat to complete their life cycle (Table 1).

The various workers had done extensive studies and documented findings on butterflies in different parts of India i.e. deNicéville (1886) focuses on specific butterfly families and subfamilies, providing detailed descriptions and classifications of species found in the Indian subcontinent; Bingham (1905-1907) done foundational work in the study of butterflies species in South Asia; Evans (1932) published the book entitled The Identification of Indian Butterflies; Arora (1994, 1995, 1997) provides a comprehensive overview of the butterfly fauna of Rajaji National Park, worked on the butterfly species of the Western Himalayas and focused on the butterflies  of the Nanda Devi Biosphere Reserve, Uttarakhand; Joshi and Joshi (2003) studied Butterfly Diversity in Bhimtal and Ramnagar Region of District Nainital; Tyagi et al. (2011) examined the diversity and distribution of butterflies in Nainital district, Uttarakhand, India; Smetacek (2012) explored the butterfly diversity along with other protected fauna in the Jones Estate; Arya and Dayakrishna (2014) investigated the species richness and diversity of butterflies in and around Kumaun University; Singh and Sondhi (2016) provided an overview of the butterfly species recorded in the Garhwal, Western Himalaya, Uttarakhand; Singh (2022) examined the diversity of butterfly species in different forest types across Uttarakhand in the Western Himalayas;  Bisht et al. (2023) examined the butterfly diversity along different altitudinal gradients in the Munsiyari region of the Western Himalayas and Chandra et al. (2023) focused on the butterfly biodiversity in the protected landscape of Nandhour Landscape, Uttarakhand, India etc.

Table 1: Species composition of Butterflies recorded from Asan Conservation Reserve and RAMSAR site, Uttarakhand, India during 2021-24.

Note: + = species present; - = species absent.

The study reveals that Ariadne ariadne (Linnaeus,1763), Catopsilia pyranthe (Linnaeus, 1758), Danaus chrysippus (Linnaeus, 1758), Eurema hecabe (Linnaeus, 1758), Junonia hierta (Fabricius, 1798), Junonia lemonias (Linnaeus, 1758), Papilio demoleus Linnaeus, 1758, Papilio polytes Linnaeus, 1758, Pieris brassicae Linnaeus, 1858, Phalanta phalantha (Drury, 1773) and Vanessa cardui Linnaeus, 1758 were the dominant species of Butterflies in the study area. The selected collection of butterflies by insect net, photography of butterflies in the study area and some of dominant butterflies species were shown in Figs. e-p. 

74 species of Indian butterflies were assessed in the IUCN Red List of Threatened Species, in that Ludlow's Bhutan Glory (Bhutanitis ludlowi Gabriel, 1942) is endangered, 03 species are assessed as vulnerable, 04 are near threatened and rest 66 species are assessed as least concern. 391 species/subspecies of Indian butterflies are listed under Indian Wildlife Protection (Amendment) Act 2022, of which 96 species/subspecies are listed as Schedule I and 295 species in Schedule II (Singh et al., 2024). One of the recorded species from the study area Hypolimnas misippus (Linnaeus, 1764) is listed in Schedule II of Indian Wildlife (Protection) Amendment Act, 2022 (Annon., 2022).

The long-term monitoring studies on Butterflies and its habitats will help us to analyse/predict climate change, other meteorological factors and will be considered as an important model group in understanding ecology of a particular landscape. The threats like habitat loss, habitat degradation, habitat fragmentation, industrial settlement, deforestation, fire, use of pesticides/weedicides/chemicals in agriculture, by illegal collection for trade many species have become very rare, some are on the verge of extinction and the population of these living creatures Butterflies has been declining in the last few decades. The illegal export/collection by visitors of rare species those restricted/threatened/endemic to particular habitats and the collection by immature workers (school/college students) will also adversely affected butterflies fauna. By the Government of India efforts in conservation of biodiversity/habitats and protection of threatened species under Indian Wildlife (Protection) Act, 1972, still there is need of public awareness/participation, interaction/collaborative work between researchers, to develop standard common methodology for research study to conserve and protect these valuable creatures. The present study reveals that the study area Asan Conservation Reserve and RAMSAR site is rich in diversity of Butterfly fauna and provide a suitable natural habitat for their survival. So far 89 RAMSAR sites declared in India, including the study area Asan Conservation Reserve that  was recognized as RAMSAR site in 2020 and Wetland of International Importance under RAMSAR Convention, aim to conserve biodiversity and sustainably use of Wetlands. Therefore, the present study made a modest attempt to highlight the current status of the diversity of butterflies, helps in planning conservation management plans for wetland and understanding the ecological patterns in the study area Asan Conservation Reserve and RAMSAR site, District Dehradun, Uttarakhand, India. 

The present study reveals that the study area Asan Conservation Reserve and RAMSAR site is rich in diversity of Butterfly fauna and provide a suitable natural habitat for their survival. So far 89 RAMSAR sites declared in India, including the study area Asan Conservation Reserve that  was recognized as RAMSAR site in 2020 and Wetland of International Importance under RAMSAR Convention, aim to conserve biodiversity and sustainably use of Wetlands. Therefore, the present study made a modest attempt to highlight the current status of the diversity of butterflies, helps in planning conservation management plans for wetland and understanding the ecological patterns in the study area Asan Conservation Reserve and RAMSAR site, District Dehradun, Uttarakhand, India.