Prabesh GC, Siddhartha Panthee and Prakash Kumar Paudel

Nestled in the majestic Himalayan landscape, Nepal—occupying just 0.03% of the total world's area—boasts a vibrant array of diversities in terms of geography, climate, flora and fauna, agrobiodiversity, ethnicities, languages, religions, and endemism, as well as traditional indigenous knowledge.

1.    Introduction

Nepal is a country of diverse elements stemming from its varied geography, altitudinal gradient, climate, and culture. The country features at least five distinct geographical regions, the world's largest altitudinal gradient ranging from as low as 59 meters above sea level to as high as 8,848 meters (Mt. Everest—the world's highest mountain). The mountainous topography influences the climate and weather patterns in complex ways. Over the years, people have lived and adapted to these heterogeneous landscapes, developing their unique cultures, languages, and civilizations, creating a cultural mosaic within a relatively small area.

2.    Physiography of Nepal: A Foundation for Diversity

Nepal's diverse physical geography is divided into six distinct regions based on altitude, landforms, climate, and soils, offering a critical foundation for ecological studies. This classification, primarily based on the country’s three main mountain ranges, sees altitudes increase progressively from south to north.

2.1 The Terai Region : The Tarai is a flat, fertile strip of land at altitudes between 60 and 300 meters, bordering India. Once covered by dense tropical forests, the Tarai now supports nearly half of Nepal's population due to deforestation and migration. It remains a key agricultural and industrial area, despite its reduced forest cover.

2.2 The Siwalik: The Siwalik Range rises to 700–1,500 meters north of the Tarai. Composed of sedimentary rock, this rugged terrain is less suitable for farming. However, fertile Dun valleys between the Siwalik and Mahabharat ranges are heavily cultivated. The region's forests are vulnerable to erosion and flash flooding due to human activity.

2.3 The Mahabharat Range: The Mahabharat Range, between 1,500 and 2,700 meters, is characterized by steep slopes and a mix of subtropical and temperate climates. Terrace farming is common here, though it contributes to soil erosion. This region is more developed in the east, but deforestation and environmental degradation are significant concerns.

2.4 The Midlands: The Midlands, ranging from 600 to 3,500 meters, include high valleys like Kathmandu and Pokhara. This region, central to Nepal’s economy and culture, is rich in biodiversity. However, extensive agriculture and deforestation have impacted its ecosystems, and not all areas are well-protected.

2.5 The Himalayas: The Himalayas, above 3,000 meters, contain the world’s highest peaks, including Mount Everest. The region has an alpine to arctic climate, with sparse vegetation above 5,000 meters. Human settlements are concentrated at lower altitudes, with high-altitude pastures used for grazing and herb collection.

2.6 The Inner Himalayas and Tibetain Marginal Mountains: The Inner Himalayas feature arid valleys above 3,600 meters, largely unaffected by the monsoon. The Tibetan Marginal Mountains lie north of the Annapurna range at altitudes of 6,000–7,000 meters. These regions are ecologically significant, contributing to the Ganges river system and hosting unique landscapes in districts like Dolpa and Mustang.

 3.    Climate Diversity 

Nepal's dramatic elevation range, from just 59 meters above sea level in Mukhiyapatti Musharniya, Dhanusha, to 8,848 meters at the summit of Mount Everest, results in an extraordinary variety of climates. This climatic gradient is shaped by the country's unique topography, where mountain ranges and deep river valleys create altitudinally induced climatic zones. In the Tropical Zone of the Tarai, warm weather and abundant rainfall foster lush vegetation. As one ascends to the Subtropical Zone in the lower foothills, the air cools slightly, yet the environment remains vibrant. The Temperate Zone in the mid-hills provides a cooler climate, ideal for diverse forests.

A map of Nepal with bioclimatic zones superimposed by protected Areas of Nepal  (Paudel & Heinen, 2015). The country has 20 protected areas and 12 buffer zones, covering 23.23% of its total area. These include 10 national parks, 3 wildlife reserves, 6 conservation areas, 1 hunting reserve, and 12 buffer zones. Today, CFs occupy nearly 2.3 million ha and are managed by over 22,000 CF user groups comprising 3 million households and nearly 57% of Nepal’s population (Pandey and Pokhrel 2021).

Higher up in the Subalpine Zone, the terrain becomes rugged, with occasional snowfall enhancing the wilderness. The Alpine Zone of the high Himalayas offers a stark, snowy landscape with minimal rainfall, while the Tundra Zone above 5,000 meters presents an extreme, snow-covered environment with sparse vegetation. This unique arrangement allows for the possibility of experiencing subtropical and alpine regions within just a few hours of walking, a phenomenon unique to Nepal.

The towering Himalayas also create a rain shadow effect, blocking the monsoon to the north and generating desert-like conditions. This "mosaic of climate and geography creates unique ecological niches," leading to an unparalleled diversity of habitats. Nepal is home to 118 distinct ecosystems, with microclimatic variations fostering tremendous species diversity. The country's ecological richness, influenced by its complex topography and climatic diversity, is truly unique.

 4.    Biodiversity 

This diverse landscape supports a remarkable range of species, earning Nepal a global ranking of 49th in biodiversity. The country is home to over 22,000 species, including a vast array of plants, mammals, birds, reptiles, amphibians, insects, and fish. Nepal ranks 10th in Asia and 27th globally for the richness of flowering plant species. Notably, Nepal hosts 6,973 species of angiosperms, 41 gymnosperms, 1,001 algae, 2,016 fungi, 792 lichens, 1,213 bryophytes, and 580 pteridophytes. Similarly, the country is home to 212 mammalian species, 886 bird species, 78 reptile species, 118 amphibian species, 10,204 insect species, and 187 fish species (MoFE, 2018).

When considering Nepal's small landmass relative to the global area, the country's biodiversity is particularly astonishing. Calculating the expected number of species based on global species diversity by category, as per IUCN (2023), and multiplying it by Nepal’s proportion of global landmass (0.03%), reveals that Nepal hosts more species than expected in several categories, such as pteridophytes, gymnosperms, mammals, and birds. Conversely, while the actual number of reptile, fish, and amphibian species appears lower than expected, this discrepancy likely reflects the limited research in these fields, as highlighted by Paudel et al. (2023). This indicates a tremendous potential for future research and exploration in Nepal's biodiversity.

Species diversity of plant kingdom in Nepal. Data are depicted as actual (MoFE 2018), expected (0.03 X global total). Global data of species diversity is derived from IUCN 2018. 

Species diversity of fauna in Nepal. Data are depicted as actual (MoFE 2018), expected (0.03 X global total). Global data of species diversity is derived from IUCN 2018. 

Species diversity of higher flora in Nepal. Data are depicted as actual (MoFE 2018), expected (0.03 X global total). Global data on species diversity is derived from IUCN 2018. 

 5.    Ethnic and Cultural Diversity

5.1 Ethnic Groups: The National Population and Housing Census 2021 reveals that Nepal is home to 142 ethnic groups, with 17 newly recognized since the previous census. These groups, including the Ranatharu, Bhoomihaar, and Banakariya, add to the vibrant cultural fabric of the nation. The ethnic diversity is striking, with the largest groups being the Kshetri (16.45%), Brahmin-Hill (11.29%), and Magar (6.9%). Conversely, the smallest communities, such as the Kusunda (253 people), Bankariya (180 people), and Nurang (36 people), are equally integral to the nation's ethnic landscape.

5.2 Religion: Nepal's religious landscape is as diverse as its ethnic composition, with ten major faiths interwoven throughout the country. Hinduism is the predominant religion, followed by 81.2% of the population, while Buddhism (8.21%), Islam (5.09%), and Kirat (3.17%) also have significant followings. Smaller communities practicing Christianity, Prakriti, Bon, Jainism, and others add further depth to the nation’s spiritual diversity, creating a rich tapestry of beliefs and practices.

5.3 Languages: Reflecting its ethnic diversity, Nepal's linguistic landscape is equally varied. The latest census identifies 124 mother tongues, with 13 languages newly documented. Nepali is the most widely spoken language, used by 44.86% of the population, followed by Maithili (11.05%), Bhojpuri (6.24%), and Tharu (5.88%). The inclusion of languages like Bhote, Lowa, and Mugaali highlights the country's ever-evolving linguistic diversity.

 5.    Conclusion

Nepal’s unique blend of natural and cultural wealth offers a rare opportunity for comprehensive studies across multiple disciplines. The underexplored species and ecosystems highlight the vast potential for groundbreaking research. 

6. Reference

1. Ministry of Forests and Environment (MoFE). (2018). 25 years of achievements of CBD on biodiversity conservation in Nepal. Environment and Biodiversity Division, Government of Nepal.
2. National Statistics Office. (2021). National report on caste/ethnicity, language and religion (National Population and Housing Census). Office of the Prime Minister and Council of Ministers, Government of Nepal.
   
3. Paudel, P. K., Baniya, S., Sharma, S., Bhandari, S., & Pokharel, M. (2023). Half century in biodiversity and conservation research in Nepal: A review. Biodiversity & Conservation, 32.
   
4. Paudel, P. K., & Heinen, J. T. (2015). Conservation planning in the Nepal Himalayas: Effectively (re) designing reserves for heterogeneous landscapes. Applied Geography, 56, 127-134.
   
5. Pandey, H. P., & Pokhrel, N. P. (2021). Formation trend analysis and gender inclusion in community forests of Nepal. Trees, Forests and People, 5, 100106.
   

(This blog is drafted  by Prabesh GC with ideas and guidance by Prakash Kumar Paudel and SIddhartha Created Graphics under Dr. Paudel 's supervision).