Carrying capacity and Himalayan vulnerability

Context: Last month, a Bench headed by Chief Justice of India D.Y. Chandrachud had suggested that an expert committee conduct a “complete and comprehensive” study on the carrying capacity of the Himalayan region.

What is the concept of “carrying capacity”?

• Carrying capacity of a biological species in a particular habitat refers to the maximum number of individuals (of that species) that the environment can carry and sustain, considering its geography or physical features.
• The physical features present in the environment act as limiting factors (e.g. food, water, competition, etc.). Thus, the population limit can be expected to depend on these factors. 
• In essence, food availability is an important variable as it affects the population size of the species. 
• It does so in such a way that if food demand is not met over a given period of time the population size will eventually decrease until the resources become adequate. 
• By contrast, when food supply exceeds demand then the population size will soon increase and will stop increasing when the source is consequently depleted.
  

• A population may grow at a faster rate and follow a J-shaped curve. When the birth rate surpasses the death rate of the species, this results in exponential growth. However, this trend soon changes as resources become limited. The growth rate slows down.
• Soon, it reaches a stable equilibrium where biomass in the given area seems unchanged over a certain period of time. At this point, the death rate appears to be compensated by the birth rate within a population. This means the per capita birth rate equals the per capita death rate. 
• By contrast, when deaths appear to outgrow births, this indicates that the carrying capacity has been exceeded. This is a case of overshoot. The population may go below the carrying capacity. This can occur, for instance, during disease and parasitic outbreaks.

Factors affecting the carrying capacity of an ecosystem:

• Food and water supply
• Habitat space, 
• Competition (intraspecific and interspecific), 
• Physical factors (e.g. extreme heat, drought, etc.), 
• Chemical factors (e.g. pH, mineral deficiency, etc.)
• Anthropogenic factors. 

• Note – The sum of these factors that end up restricting the biotic potential of a species is referred to as environmental resistance.

Why Himalayan ecosystem is unique?

• These systems, with their steep slopes and sharp gradients, are heterogeneous and exhibit sharp and most often systemic changes in climatic variables over very short distances. 
• These features consequently result into enhanced changes in hydrological processes, with accelerated direct runoff and erosion. 
• Major rivers of the region have their origin from these mountains and are the source of water for a large proportion of the human population within and outside the mountain region. 
• Many of the world’s crops originate in mountains, a crucial resource that should be conserved for sustaining modern agriculture. 
• Natural wealth in the region, including geological assets, forms an important part of the Himalayan eco-system. 
• All this has contributed to a whole range of diversity in indigenous human habitations, cultures and knowledge systems. The region is largely inhabited by indigenous societies. 

Therefore, sustaining biodiversity in the region also means protecting the interests of the people. The region serves as a rich repository of plant and animal wealth in diverse ecological systems. These ecosystems reflect a mosaic of biotic communities at various spatial and organizational levels.

Recognition of the Himalaya as one among 34 global biodiversity hotspots aptly reflects its’ wide ranging ecological significance.

The vulnerability of the biological and physical features of the Himalayan Ecosystem towards natural and human induced disturbances is well recognized. Immediate actions are required to ensure sustenance of the ecosystem.

Infrastructure effect on Himalayan region:

Infrastructure like dams, roads, hotels, industries etc are increasing the vulnerability of the Himalayan ecosystem in multiple ways. Joshimath crisis is one such example.

Following are the various impacts: 

Slope destabilization – Large scale construction of roads, hotels, powerhouses etc. involves blasting, quarrying, deforestation and muck disposal which loosens slopes and destabilizes them.

Floods – Altered river flows reduce flood absorption, risks flash floods downstream (Uttarakhand disaster, 2013). 

Landslides – By disrupting underground streams and aquifers, tunnels can weaken slope stability leading to landslides (Kinnaur, Himachal Pradesh 2022)

Earthquakes – Huge pressure is exerted by the large structures of the dams which in turn create fractures and faults in the rocks below generating earthquakes. For e.g – Koyna dam.

Erosion and desertification – Siltation in dams devoid the rivers of natural sediments. Soil downstream does not get enough nutrients and thus issues of soil erosion, desertification etc rises. Forced displacement – This destroys livelihood sources of indigenous communities further increasing their vulnerabilities.