My Research Portfolio
Welcome to my research portfolio. Here, you’ll find a selection of my work. Explore my research projects to learn more about what I do.
Thank you!
Deadwood & Biodiversity: Global Meta-analysis
This project is a section of my Ph.D. research, which centers on forest ecosystems and aims to investigate the advantages of deadwood for biodiversity conservation and its role as a carbon stock, as well as its influence on wildfire hazards.
Deadwood is essential for maintaining forest biodiversity and plays a pivotal ecological role in biodiversity conservation, carbon cycling and storage, and nutrient dynamics. It serves as a critical habitat for numerous species, including saproxylic, epixylic, and non-saproxylic organisms.
Utilizing a meta-analytic approach, I have synthesized the relationships between deadwood and biodiversity in forest ecosystems by incorporating data from 40 studies conducted across 22 countries. This research has unveiled significant positive correlations between deadwood and biodiversity, regardless of the bioclimatic regions, forest types, and management practices. Nevertheless, notable differences have been observed among various types of deadwood and decay stages, indicating that both the quantity and quality of deadwood are crucial factors for forest biodiversity.
Key findings:
-
The biodiversity of all species combined and rare species had significantly positive correlations with the dead wood amount.
-
Variations in effects were not apparent among bioclimatic regions, forest types, stands, and management regimes.
-
Correlations varied among dead wood types and decay stages, implying that dead wood quality attributes are critically important for biodiversity.
Link to published article:
Parajuli, R. & Markwith, SH. (2023). Biological Conservation, 283.
Langtang Positive Interaction Research
During my master's studies in 2009/10, extensive engagements in research tours and expeditions in the Himalayas were crucial in instilling my interest in plant adaptations to harsh environments and the factors that shape high-elevation plant communities. I keenly observed the herbaceous species, including rare medicinal herbs, thriving beneath specific shrubs, cushions, or trees. This inspired my exploration of how these nurse species, like shrubs, sustain plant diversity and structure community assembly in the high-elevation Himalayas.
This concept, which had yet to be tested in the Himalayas, secured a competitive research grant from the Rufford Foundation, UK.
I conducted a study on plant species interactions, explicitly focusing on the facilitative roles of shrubs and cushions in maintaining plant biodiversity in the high-elevation alpine and subalpine regions of the Langtang region of the Himalayas. A portion of this research constituted my MS Thesis, primarily focusing on the nurse effect of Himalayan native Berberis shrubs on plant diversity, including medicinal herbs, in a high-altitude landscape in Nepal’s Central Himalayan region.
This research revealed that the facilitation provided by Berberis shrubs was critical for maintaining plant biodiversity and provided refugia for rare and threatened species, including high-value medicinal herbs and other species valued by humans. Moreover, this study shed light, for the first time, on the valuable ecosystem services provided by plant facilitation and how the outcomes of shrub-herb interaction patterns are influenced by elevation gradients, growing seasons, and their combinations.
Links:
Fig.: Dactylorhiza hatagirea, a threatened medicinal herb, protected by Berberis shrub in the Himalayas.
Global Cushion Diversity Experiment
In 2010, when I was doing my MS degree, I became a part of a global research project, the Cushion Diversity Experiment, collaborating with the Alpine Pals group representing Nepal's Himalayas. The project aimed to assess the effects of cushion foundation species on alpine plant diversity at a global scale. We researched 78 sites on five continents using a standardized sampling protocol. Our study examined whether facilitative plant interactions influence alpine plant biodiversity, particularly looking into the role of cushion species in community assembly and phylogenetic diversity in harsh alpine environments.
This research showed that nurse cushion species substantially contribute and serve as a 'safety net' for sustaining plant biodiversity in environmentally severe and ecologically sensitive alpine regions. Our results highlighted the importance of nurse cushion plants as 'micro-refugia' in maintaining phylogenetic diversity in alpine areas worldwide. The cushion species create unique niche spaces that benefit less stress and disturbance-tolerant species for their recruitment and establishment within the community. As a part of this collaborative project, I coauthored three articles published in high-impact journals such as Ecology Letters and Ecology.
Links to published articles:
Butterfield et al. 2013. Ecology Letters 16(4) 478-486