Diversity of moths Lepidoptera: Heterocera) and their potential role as a conservation tool in different protected areas of Uttarakhand

Abstract

Moths have long been regarded as the “poor cousins” of butterflies in Lepidoptera conservation, and have lagged well behind butterflies in popularity and in the attention given to their conservation status and needs. Only rarely do they gain greater prominence, despite the enormous taxonomic and biological variety they display. Forest moth species have important functional roles as selective herbivores, pollinators, detritivores, and prey for migratorial passerines. Furthermore, they have shown promise as forest indicator taxa. Keeping in view of these various roles of moths in ecosystem, the present study is proposed to be undertaken in the Western Himalayan Landscape of Uttarakhand, in 12 protected areas: Corbett NP, Rajaji NP, Gangotri NP, Govind NP, Nanda Devi NP, Valley of Flowers NP, Askot Musk Deer WLS, Binsar WLS, Govind Pashu Vihar WLS, Kedarnath WLS, Mussoorie WLS and Sonanadi WLS. The objective of this study was to document rich moth fauna of Uttarakhand. The study was an interesting attempt to make an inventory of moth species in various sites and to see diversity and richness with respect to different vegetation structure and composition and measure different habitat covariates. The influence of climatic, topographic and anthropogenic effect on moth assemblages were studied. The study expects to establish moth assemblage as surrogate for entire insect community and use them as indicator taxa in rapid habitat-quality assessment program. The study was conducted in some Protected Areas of Uttarakhand: 1) Nanda Devi Biosphere Reserve 2) Gangotri National Park 3) Govind Wildlife Sanctuary 4) Askot Wildlife Sanctuary The study area was stratified on the basis of elevation & vegetation types to explore the moth diversity along the gradient. Each site will was selected randomly at a particular elevation band so that the vegetation types are included in them. The number of trap sites were selected at each stratum so that comprehensive representation of the moth diversity can be accounted. The trap sites were situated in the centre of plots with a homogeneous vegetation cover, so that moth catches at weak light sources should largely reflect the local communities. The minimum distance between neighbouring sites were 50 m, with lamps not being visible from neighbouring sites, so that cross-habitation sampling does not occur. At each site 2-3 night sampling were done for 3-4 hours from dawn. The moths were trapped by their attraction to weak light sources. 5days prior to and after full moon were not sampled. iii Among five subfamilies of Geometridae sampled across different elevation and forest types, Ennominae was the dominant (92 species), followed by Larentiinae (37 species), Geometrinae (28 species), Sterrhinae (11 species) and Desmobathrinae (1 species). Altitudinal distribution of the four major subfamilies (Figure 3) showed that the subfamily Larentiinae was exceptionally distributed towards higher altitude while the other three were diverse in lower and middle elevation zones. We documented 36 species which were previously unrecorded from Uttarakhand. Among them 19 species were of subfamily Ennominae: Anonychia violacea, Biston falcata, Psilalcis inceptaria, Medasina interruptaria, Medasina cervina, Erebomorpha fulguraria, Ourapteryx convergens, Arichanna tenebraria, Gnophos albidior, Hypomecis ratotaria, Loxaspilates hastigera, Odontopera heydena, Odontopera lentiginosaria, Plagodis inustaria, Psyra debilis, Opisthograptis sulphurea, Opisthograptis tridentifera, Sirinopteryx rufivinctata and Tanaoctenia haliaria; 3 species of subfamily Geometrinae: Chlorochaeta inductaria, Chlorochaeta pictipennis, Pingasa rubicunda; and 13 species were of subfamily Larentiinae: Photoscotosia multilinea, Photoscotosia metachryseis, Cidaria aurata, Electrophaes recta, Eustroma chalcoptera, Hydrelia bicolorata, Stamnodes pamphilata, Trichopterigia rufinotata, Triphosa rubrodotata, Perizoma albofasciata, Euphyia stellata, Xanthorhoe hampsoni and Heterothera dentifasciata. One species Rhodostrophia pelloniaria of subfamily Sterrhinae was also the first record from Western Himalaya. In Nanda Devi Biosphere Reserve species of Geometridae family were found to be most abundant in both Joshimath (0.71) and Lata (1.15) gradient across all the sampling plots. The second most prominent family is Noctuidae with high abundance in Lata (0.65) but low abundance in Joshimath. The temperate forest type showed the maximum species richness in both Joshimath (243) and Lata (150) gradient. The extent of temperate forest type was the most within our sampling altitude range (2000-3800m) and is more heterogenous in vegetation structure with mixed coniferous tree species diversity (Pine-Fir) in the lowest reaches and oak and deodar species in the midaltitudes. The highest elevation band in Joshimath gradient was 3200m, so there was no sampling in the alpine scrubland forest type in this gradient In Gangotri National Park and Govind Wildlife Sanctuary the diversity was maximum in lower altitude zone and decreased gradually in three subsequent zones (Fig 7a). Fisher’s alpha was highest, 85.37±3.31 in 1400m-1900m, and lowest 48.02±1.75 in 2900-3400m. Simpson’s Index was 112.14±4.56, 93.27±3.84, and 76.04±4.73, iv 65.89±2.74 in 1400-1900m, 1900-2400m, 2400-2900m and 2900-3400m respectively. Observed species richness and estimated species richness (Fig. 7b) was 271, 293.54±9.37 for 1400m-1900m, 193, 196.76±3.07 for 1900m-2400m, 203, 217.8±8.26 for 2400m-2900m and 203, 211.09±5.17 for 2900m-3500m. The percent completeness, represented as ratio between observed species richness and estimated species richness was 92%, 98%, 93%, and 96% respectively for the four altitudinal zones studied. Alpha diversity (Fisher’s alpha) and Simpson’s index were highest (Fig 8a) in Subtropical Pine Broadleaved Mix forest (80.89±3.56, 105.18±7.56) and Western Mix Coniferous forest (82.66±2.84, 108.23±2.4) and lowest in Subalpine forest (47.47±1.9, 62.36±2.94). Almost similar diversity patterns were recorded in Moist Temperate Deciduous forest (48.21±2.51, 71.43±5.74) and Western Himalayan Upper Oak forest (56.69±2.24, 70.97±3.38). At habitat level also, relatively, sampling success was achieved with no major difference in observed species richness and estimated species richness using Chao 1. Observed and estimated species richness was highest (Fig. 8b) in Western Mixed Coniferous forest (294, 306.99±6.11) and lowest in Moist Temperate Deciduous forest (152, 156.26±3.24). The values for observed and estimated species richness for other vegetation classes were like 237, 264.84±11.56 for Subtropical Pine Broadleaved mix forest, 210, 226.13±8.29 for Western Himalayan Upper Oak forest and 187, 193.86±4.67 for Subalpine forest. In conclusion, despite gradual and small distances between various habitat types studied, each one had significant resources to support its own characteristic moth assemblage. Overall, local diversity among moth communities were high all through the gradient signifying enough resource availability at every altitude and vegetation zones studied. The high diversity documented for the first time of a major herbivorous insect community in this typical Western Himalayan altitudinal gradient can be instrumental enough to ascertain its conservation significance. The results confirm that unless sampled extensively over a large temporal scale, the recorded species number is an unreliable measure of diversity because of its dependence on the number of specimens collected. Use of a set of sample size independent diversity measures like Fisher’s alpha, Chao I and Jackknife should complement each other in different aspects of diversity as well as mathematical assumptions underlying their usage. Concordant diversity picture yielded by all these different measures should also minimize the possible risk of misinterpretations.This study has covered an elevational range from 600m-3800m spread across different protected areas of Uttarakhand. Still there is a gap in moth samples between 1000m- 1500m, which is mainly due to the absence of suitable natural sites in this range which are free from human disturbance. The sampling of entire elevational gradient would generate a more discernible pattern with relevant ecological explanations. Although our data is still scattered and more intensive sampling can result in more addition to this species record of Geometridae, future research on this current database should benefit the conservation of entire moth assemblage and their habitats in Western Himalayan Biogeographic province.