Biodiversity Nepal
For the Future Generation

Forest Fire: A Cause of Biodiversity Loss

Assembling impacts of wildfire in biodiversity


A lavishly grown, dark and evergreen forest arms thousands of species within itself. Considering only trees as a constitute of the forest is an error. It is much more than just an assemblage of trees. From sheltering wild lives, protecting watersheds to addressing human’s needs and greed’s its significance can never go out of sight. Nepal is a great surprise to the world when it comes to biodiversity. Within a limited territory, it hosts about   5.5 million ha or 37.4% of the total area of forest. The “other land” category covering another 15.7% has good potential for development into forest or pasture.

 It is said that when things are important then they are vulnerable too. The destruction of forests is going at an alarming rate. The surging climate change and human negligence have caused uncontrolled forest fire which has changed the whole dynamics of biodiversity. According to reports, wildfires were burning in at least 60 places across 22 of Nepal’s 77 administrative districts. Forest fires often erupt in Nepal during the January-May dry season, when villagers burn dry leaves in the woodlands to prompt fresh grass growth for their cattle. The number of fires this year was 15 times the number of fires in 2020. But we don’t immediately have a reason for the increase. A hill was burned during a forest fire in Makwanpur located at the outskirts of Kathmandu valley. The big forest fires in Pathibhara in eastern Nepal and below Mt Machapuchre in Kaski, Manang, Rasuwa, Lamjung and Sindhupalchok destroyed the vegetation, habitats of wild animals and localized flora and fauna. The fire was ignited accidentally because of people grazing livestock or gathering firewood. The fire has destroyed over 700 hectares of forest rich in endangered wildlife and Himalayan plant Mustang. It is estimated that Nepal has been losing around 200,000 hectares of forest cover every year since 2005 to forest fires. About 90 per cent of wildfires are human-induced. Most of these fires have been linked with deliberate burning while making land for farming, while collecting non-timber forest products, due to human negligence.

The crawling and crown fire has destroyed the forest land, vegetation and wild lives. Fire is an agent of transformation which affects biotic and abiotic components of the ecosystem and alters the productive, protective function of a forest. These effects are highlighted in the ecosystem fragmentation, alteration in ecosystem structure and function as well as biodiversity status of an area. The prominent effect of fire is storm water runoff that promotes the transportation of debris and sediment into larger bodies of water resulting from the pollution of valuable and essential resources. The flames from the fires destroy the food source and shelters of many wild lives, threatening their survival. The plants and trees that can survive the flames are susceptible to disease, fungus, and insects due to their decreased resistance following burn injuries. Forest fires raging on steep slopes lead to rockfall even if the fire is still burning. If the leaves and topsoil are consumed by fire, the destabilized stones are set in motion. The layer of ash created by the fire becomes water-repellent as a result no rainwater is able to be absorbed by the soil for one to two years which creates surface runoff. This causes erosion, especially in heavy rain. Organic nutrients of the soil are degraded or swept by wildfires so the production of biome is questionable. Fire affects nutrient cycling and the physical, chemical, and biological properties of soil. Soil heating directly affects microorganisms by either killing them directly or altering their reproductive capabilities.

The habitat changes caused by fire influence faunal populations and communities much more profoundly. Small carnivores respond to fire effects on small mammal populations (either positive or negative). Large carnivores and omnivores are opportunistic species with large home ranges. Their populations change little in response to fire. Fires reduce habitat quality for species that require dense cover and improve it for species that prefer open sites. Population explosions of wood-boring insects, an important food source for insect predators and insect-eating birds, can be associated with fire-killed trees. Animals’ immediate response to fire may include mortality or movement. It is influenced by fire intensity, severity, rate of spread, uniformity, and size. Long-term faunal response to fire is determined by habitat change, which influences feeding, movement, reproduction, and availability of shelter. Alteration of fire regimes alters landscape patterns and the trajectory of change on the landscape. These changes affect habitat and often produce major changes in faunal communities.  Fire influences the composition, structure, and landscape patterns of animal habitats. For animals, the vegetation structure spatially arranges the resources needed to live and reproduce, including food, shelter and hiding cover. Some fires alter the vegetation structure in relatively subtle ways, for example, reducing litter and dead herbs in variable-sized patches. Wildfires add difficulties to the existence of animals. The sudden change in their adaptation cause them to either extant, sustain or extinct. Fires influence birds indirectly through habitat modification, changes in the food supply, or changes in abundance of competitors and predators.

The havoc created by wildfire leaves no edge unturned. In just seconds, a spark or even the sun’s heat alone sets off the whole forest on fire. The wildfire quickly spreads, consuming the thick, dried-out vegetation and almost everything else that comes in its path. Today, the need for a healthy environment is expressed in greater intensity. Concrete plans and actions should be taken to contain an uncontrolled fire in order to conserve valuable species of nature.

Author: Dikshya Neupane is an enthusiastic youth motivated to work in the field of biodiversity conservation.