Effect of snowmelt regime on phenology of herbaceous species at and around treeline in Western Himalaya, India

Bhupendra S Adhikari,Rahul Kumar

doi:10.15835/nsb12410716

Abstract

The present study attempts to investigate the phenological changes of herbaceous plant species in early snowmelt microsite and late snowmelt microsite in treeline ecotone (3200-3300 m asl) at Tungnath, western Himalaya. Four sites, each with two microsites (early snowmelt: ES and late snowmelt: LS) were selected and within each microsite, 3 quadrats (1x1m each) were permanently laid and studied for phenology. Eighty-six species were recorded, of which the proportion of perennial forbs, hemicryptophytes and natives was 90, 84 and 70%, respectively. The early phenophase was noticed in the majority of species in ES microsite than that of LS microsite and the timing of different phenophases varied among microsites. The vegetative phase peaked July (75.6%), while flowering, fruiting and seed maturation phases peaked in August (72.1% and 23.3%, respectively) and 71% species attained the senescence during September. This indicates that species might adapt to the different adaptation to a warming climate. Immediately after the snowmelt 10 species were observed in flowering, while 11 species were in the bud development phase. Comparing 13 common species of the present study with those of past in same or similar study areas indicates that timing and duration of vegetative and flowering phenophase (77% and 69%, respectively) have advanced and lengthened, while fruiting and seed maturation have shortened. Furthermore, phenophase initiation has advanced for flowering (69% species), fruiting (46% species) and senescence (38% species) phases. It seems that the early snowmelt influences spring phenology of herb species on the microsite level and may continue to influence the overall phenology of species for the whole growing season in timberline.

Highlights

A certain elevation, due to ‘physiognomic discontinuum’ (Singh, 2018), there is a transition from trees to herbaceous meadows which can be seen as an imaginary line separating meadow from the forest through short stature tree patches/krummholz (Körner, 2012a)
Most of the snow manipulation experiments have been conducted in the temperate or boreal forest with inconsistencies in experimental settings, as these experiments are in-situ, but literature is severely lacking in the Indian Himalayan Region (IHR)
The present study sheds some light on phenological behaviour of herb species to snowmelt timing in treeline regions of IHR, many other key questions remain unanswered as different ecophysical environments may result with a different response, especially anthesis of herb species across different functional groups, which will result in completion and final adjustment between species for the resource

Summary

Introduction

Due to ‘physiognomic discontinuum’ (Singh, 2018), there is a transition from trees to herbaceous meadows which can be seen as an imaginary line separating meadow from the forest through short stature tree patches/krummholz (Körner, 2012a) This transition is driven by temperature decline due to increasing elevation (Mayor et al, 2017) and represents an ecotone of vast biodiversity importance (Callaghan et al, 2002; Singh, 2018) as vascular plants decrease with an altitudinal gradient (Mohapatra, 2015) leading to increase in endemic (Dhar, 2000) and native species.

Methods

Results

Discussion

Conclusion