Source: The Hindu Relevance: GS I (Salient Features Of World’s Physical Geography)

Context: The earth’s tropical areas receive more sunlight, so they should be the most biodiverse places. Mountains defy this rule. Alexander von Humboldt introduced the idea of Humboldts enigma in the 19th century. This idea proposes a relationship between humidity, temperature, altitude, and biodiversity.

Humboldt's Enigma:

  • Inspired by the findings of Alexander von Humboldt, it challenges the widely held belief that tropical areas, with their abundance of sunlight, are the main hubs of biodiversity on Earth.

  • According to Humboldt’s enigma, biodiversity isn’t limited to the tropical areas of Earth.

  • It suggests a significant presence of biodiversity in non-tropical areas, such as mountainous terrains.

  •  For example, India showcases its vast biodiversity not only in tropical areas like Chhattisgarh and the Western Ghats but also in the eastern Himalayas, characterized by diverse geological structures and varying climates.

Different drivers of biodiversity:

  • The three main elements that drive biodiversity are the earth’s history, geography, and climate.

  • Geological Process of Mountains: As a result of geological processes like uplifts that produce new habitats, mountains serve as the cradles for new species.

  •  Climatic Stability: Because these mountains have a stable climate, they have accumulated a variety of species over time, transforming these areas into museums.

  •  Coastal tropical sky islands: The Western Ghats’ Shola Sky Islands show characteristics of a museum and a cradle for species. 

  • For this reason, the Shola Sky Islands are home to some of the oldest bird species found in the Western Ghats, including the Montecincla and Sholicola.

Factors That Affect Mountain Biodiversity:

  • Varied Topography: Mountains present a variety of microclimates, from snow-covered summits to sheltered valleys, fostering diverse ecological niches and supporting a wide range of species.

  • Isolation Effect: Acting as isolated "islands" in the air, mountains encourage unique evolutionary trajectories and the emergence of endemic species distinct to these environments.

  • Evolving Landscapes: Geological activities like landslides and the retreat of glaciers constantly reshape mountain landscapes, facilitating the establishment and evolution of new species.

Unanswered Questions:

  • Complexity of Biodiversity: Over a hundred ideas have been proposed as a result of the various causes that drive diversification and Humboldt’s conundrum in different places.

  • Data Limitations: Exact explanations are impeded by the absence of fine-scale species occurrence data.

  • Research Call: To fully comprehend genuine biodiversity, additional in-depth research is required in India’s understudied regions, including the use of genetics.

  • National Initiatives: To fund basic research, initiatives like the National Mission on Himalayan Studies and Biodiversity need to be strengthened.

  • India’s many mountain ranges, such as the Himalayas, particularly the Eastern Himalayas, provide perfect environments for examining Humboldt’s mystery.

  • The Eastern Himalayas are home to hundreds of species, including approximately 10,000 plant species, 900 bird species, and 300 mammal species, according to the World Wildlife Fund  of which a large number are severely endangered or endangered.

  • The densest populations of Asian elephants, one-horned rhinos, and Bengal tigers can be found in its grasslands.

  •  Snow leopards, red pandas, takins, Himalayan black bears, and golden langurs can be found hiding in its mountains, while the rarest dolphins in the world can be found in its rivers (Gangetic).

In summary, Humboldt's enigma underscores the complexity of natural ecosystems and the need for a nuanced approach to environmental science, conservation, and policy-making. It highlights the interconnectedness of global ecosystems and the importance of preserving biodiversity across all types of environments.

Advait IAS