Plant density and life history traits of Aconitum spicatum in North-central Nepal: effects of elevation and anthropogenic disturbances

Abstract

Increasing cross-border trade of medicinal and aromatic plants (MAPs) has put heavy pressure on a considerable number of species in the Himalayas. One of the threatened species in Nepal is Aconitum spicatum. Unfortunately for this species and for many others, our knowledge on population ecology and performance across the distribution range is insufficient, hindering the formulation of species-specific management plans. We therefore studied density and population structure of A. spicatum and assessed variation in its life history traits among three populations (subalpine, lower alpine and alpine) along an elevation gradient (3,000–4,200 m a.s.l.) in Annapurna Conservation Area, north-central Nepal. The results show that human disturbances and topographic factors contributed to the variation in density and life history traits. The overall density ranged between 0.56 ± 0.09 (Mean ± SE) and 2.48 ± 0.24 plants/m2 with highest mean density in the lower alpine and lowest in the subalpine population. The subalpine population was also characterized by lower investment in reproductive structures with lowest seed mass and low seed viability and fecundity. Among the environmental variables tested, harvesting, animal droppings and fire appeared to be the most important factors affecting density of different life stages of A. spicatum. The prevailing harvesting pattern is destructive as it involves uprooting of the whole plant and this appears to be a main reason for low recruitment and reduced density of the subalpine population. The level of disturbance decreased with increasing elevation. In terms of reproductive effort, the alpine population performed best. Our results indicate that the viability of A. spicatum populations depends on controlling over-harvesting and pre-mature harvesting of tubers and protecting younger life stages from grazing, trampling and fire. We therefore recommend that when formulating management guidelines, measures aiming to mitigate such anthropogenic disturbances should be considered.

Illegal harvesting and livestock grazing threaten the endangered orchid Dactylorhiza hatagirea (D. Don) Soó in Nepalese Himalaya

“…We established the temporary plots using the methods described by Chapagain et al (2019). At each site, we identified three populations of D. hatagirea along an elevation gradient ranging from 3,400 to 3,900 m along the Upper Chamelia valley of ANCA and 3,400-4,600 m along the Gyasumdo valley in Manang (Figure 1, Table S1: Appendix S1).…”

“…Environmental conditions and interactions associated with altitude play a significant role in the composition and distribution of orchid populations Djordjević et al, 2016Jacquemyn et al, 2005). Alpine and subalpine grasslands suffer from reduced nutrient availability and harsh environmental conditions, and plants growing in these habitats presumably develop adaptive coping strategies (Chapagain et al, 2019). Disturbance regimes, such as harvesting, grazing, trampling, and fire, also play influential positive (Chen et al, 2014;Dai et al, 2019) or negative (Chapagain et al, 2019;Kreziou et al, 2015) roles in determining the growth and persistence of plants and could be important elements of an optimal grassland management strategy for alpine meadows.…”

“…The traditional practices of transhumance, harvesting, and habitat fragmentation are likely the major anthropogenic factors responsible for reducing the flowering density as well as the population size of D. hatagirea in the unprotected site. Human-induced disturbances like harvesting, grazing, and fire have negative effects on population density and performances(Aguilar et al, 2006;Chapagain et al, 2019;McKinney, 2002); however, there are also examples of the opposite, andChen et al (2014) actually reported a positive effect of human disturbance on some orchid species. Our results further suggest that at both sites the density of D. hatagirea reached a peak in mid-elevation populations (3,799 m asl in the unprotected and 4,046 masl in the protected site).…”

Traditional socio-cultural utilization and harvesting practices of an alpine medicinal herb, Neopicrorhiza scrophulariiflora in Khumbu Valley, Nepal

“…In such situations where younger generation is reluctant to peruse traditional practices, preservation of traditional knowledge and effective methods for knowledge transfer within the society, along with resource protection, become essential. Medicinal and aromatic plants growing at higher elevations are sensitive to harvest (Chapagain et al 2019(Chapagain et al , 2020Ghimire et al 2008b;Poudeyal et al 2019), and overharvesting poses a significant threat to the population of many such species in Nepal (Chapagain et al 2021, Ghimire & Nepal 2007, Ghimire et al 2005. In Khumbu Valley, harvesting of very small amount of Neopicrorhiza strictly for local use probably may not pose great threat.…”

Spatial analysis and distribution modeling of Aconitum moldavicum in Ukrainian Carpathians and adjacent territories with special reference to the algorithm used

“…The elevation is frequently reported as one of the key factors, affecting the distribution of plant taxa, especial endemic, in different mountain regions (Vetaas & Grytnes, 2002;Wang et al, 2003;Singh et al, 2007;Subedi et al, 2015), including Carpathian Mountains (Tsaryk et al, 2003;Piękoś-Mirkowa & Mirek, 2009;Kyyak et al, 2016;Mráz et al, 2016). In particular, elevation has confirmed influence on the origination of genetic diversity and speciation in mountain plants (Thiel-Egenter et al, 2009), including Aconitum representatives (Hardin, 1964;Sutkowska et al, 2013;Chapagain et al, 2019). In our preliminary investigations, we have also suggested that elevation may be the factor determining the structure of the inflorescence in A. variegatum L. (Novikoff, 2009).…”