Loss of biodiversity in Eastern Himalayan Region

The Eastern Himalayan Region, known for its unique and diverse floral and faunal biodiversity, forms a part of the Himalayan Biodiversity Hotspot. Monsoon showers, the low-lying floodplains of the Brahmaputra, steep mountains, and the rain-shadow effect on the northern slopes of the Himalayas contribute to the region’s exceptional biodiversity. According to a study, the Eastern Himalayas harbor approximately 450 avifaunal species not found in the Western Himalayas.
Species diversity, richness, and distribution patterns in the Eastern Himalayan forests are regulated by altitude and environmental factors (Saikia et al., 2017).

Biodiversity loss, associated with permanent ecological changes, can lead to ecosystem dysfunction. While biodiversity hotspots represent 2.3% of the Earth’s land surface, reports indicate that 86% of their habitats have been lost due to climate change and human activities. The Living Planet Report 2022 states that since 1970, there has been an average 69% decline in mammal, bird, reptile, fish, and amphibian populations. Data from WWF indicates that over 75% of the original Himalayan habitat has been degraded. Human development, pollution, resource overexploitation, and climate change are major contributors to the steep decline in Himalayan biodiversity (ICIMOD report). The WWF also highlights that fuelwood collection, land conversion, overgrazing, and other activities have altered habitats in the Eastern Himalayas, exacerbating species loss and ecosystem degradation.

Extensive livestock grazing damages the forest understory, disrupting ecosystem composition. Deforestation for fuelwood, timber, shifting cultivation, and plantations has caused significant forest loss in the region. One of the consequences of deforestation is soil erosion, particularly in northeastern states prone to heavy rainfall. Changes in topography, vegetation, and canopy cover further exacerbate soil erosion.

Climate change and habitat loss are emerging drivers of biodiversity loss. A study reports that 36% of protected areas in the Eastern Himalayas are highly vulnerable to climate change. Over the past 50 years, the region has experienced a 1.3°C increase in temperature, reduced summer monsoon rainfall, and an increase in extreme weather events. The “Third Pole,” which supplies nine major Asian rivers and sustains over 1.5 billion people, is increasingly vulnerable to environmental changes.

Biodiversity loss and climate change are interrelated crises. Loss of biodiversity undermines carbon sequestration, amplifying climate change (Weiskopf et al., 2024). A recent study reveals that biodiversity loss reduces global terrestrial carbon storage, as carbon sequestration is linked to biological diversity. Under intense climate change and land-use scenarios, greater biodiversity loss leads to higher carbon emissions. A recent analysis suggests that maintaining tree diversity could prevent 9-36% of productivity loss across biomes.

Climate change has disproportionately impacted the Himalayas compared to Indian plateaus and plains (Krishnan et al., 2020). High-elevation sites, in particular, have seen greater climate vulnerability over the past five decades, putting high-altitude species at risk of extinction.

The State of the Forest Report 2021 reported a loss of 1,072 sq km of forest cover in Himalayan states. According to the National University of Singapore, by 2100, only 10% of Indian Himalayan land may retain dense forests. In the Eastern Himalayas, dense forest cover is projected to decline from 7.2% in 2000 to 38.7% by 2100.

The Eastern Himalayas, characterized by agrarian economies and forest-based livelihoods, face significant land resource pressures. Climate change and economic development heavily impact this fragile ecosystem.

Impacts of Biodiversity Loss

1. Ecosystem Resilience and Function
   Loss of biodiversity disrupts ecosystem services and reduces resilience to disturbances. Diverse ecosystems are more stable and better equipped to adapt to climate change. Reduced genetic diversity, caused by climate change, habitat fragmentation, and population decline, threatens species’ adaptive potential and long-term survival.
2. Impact on Communities
   Biodiversity supports ecosystem productivity, stability, and socio-economic development. Its loss undermines ecosystem functionality and directly impacts communities reliant on these ecosystems.
3. Health and Hunger
   Loss of crop diversity and climate-resilient crops increases dependency on agrochemicals, exposing populations to pollutants. The lack of wild medicinal plants compromises the health of 60% of the global population relying on traditional medicine. Declines in fish diversity affect nutrition security, as fish are a primary protein source for many communities.
4. Food Security
   Biodiversity loss threatens global food security, sustainable development, and poverty eradication. Loss of genetic diversity reduces crop yields, while soil biodiversity loss diminishes soil resilience and fertility.
5. Disease Vulnerability
   Biodiversity loss is linked to the emergence of infectious diseases, as highlighted in Nature. The COVID-19 pandemic, believed to have origins in bats, exemplifies this connection.
6. Livelihood Security
   Forest biodiversity sustains 275 million people in India through forest resources and ecotourism. Its loss disrupts industries like agriculture, fisheries, and forestry, increasing economic vulnerability.
7. Traditional Knowledge and Cultural Heritage
   Biodiversity underpins traditional medicine, agriculture, and cultural practices. Its loss threatens indigenous knowledge, agricultural resilience, and cultural heritage.
8. Increased Vulnerability to Natural Disasters
   Biodiversity loss reduces ecosystems’ ability to buffer natural disasters, increasing communities’ vulnerability.

Way Forward

The Food and Agriculture Organization of the United Nations reports declining biodiversity and resilience in Asia-Pacific forests. To combat biodiversity loss and climate change, measures like forest restoration and ecosystem resilience are crucial. The 2030 Biodiversity Target aims to restore 30% of degraded ecosystems, ensuring food security, nutrition, and livelihoods for local communities.

Conservation efforts should involve stakeholders, particularly forest-edge communities dependent on biodiversity. Systematic mapping of conservation sites and evaluating climate change and anthropogenic pressures are essential for safeguarding the Eastern Himalayan ecosystem.