Introduction

The question of where biodiversity is concentrated has intrigued explorers and naturalists for centuries. Humboldt has tried to answer this question.

Humboldt’s Insights

Alexander von Humboldt: A polymath of the 18th century, Humboldt recorded diverse natural observations, proposing a relationship between temperature, altitude, humidity, and species distribution.
Mountain Exploration: During his exploration of South America, Humboldt studied plant distribution on mountains, noting variations with elevation.
Chimborazo Mountain: Humboldt used Chimborazo Mountain in Ecuador as an example, illustrating the concept of mountain diversity.

Sun’s Energy: Tropical areas receive more solar energy, fostering greater primary productivity and biodiversity due to the availability of ecological niches.
Mountain Exception: Mountains, despite being outside the tropics, have been an exception to the rule, posing Humboldt’s enigma.

Earth’s History, Geography, and Climate: These factors are the primary drivers of mountain diversity.
Geological Processes: Mountains serve as ‘cradles’ for new species due to geological processes like uplifts, creating new habitats.
Climatic Stability: Climatologically stable mountains act as ‘museums,’ preserving species over time.
Coastal Tropical Sky Islands: Examples like the Shola Sky Islands in the Western Ghats exhibit both cradle and museum characteristics.

Diversity Beyond Tropics: Eastern Himalaya boasts exceptional diversity, challenging the conventional tropical biodiversity paradigm.
Multiple Factors: Climate dissimilarity and geological heterogeneity contribute to high biodiversity.
Climate Variability: Different temperature and rainfall levels on the same mountain support diverse biomes.

Complexity of Biodiversity: Numerous factors drive diversification and Humboldt’s enigma in different regions, leading to over a hundred hypotheses.
Data Limitations: Fine-scale species occurrence data are lacking, hindering precise explanations.
Call for Research: India’s under-studied areas need more extensive research, including the use of genetics, to understand true biodiversity.
National Initiatives: Programs like the National Mission on Himalayan Studies and Biodiversity need strengthening to support basic research.

Humboldt’s enigma represents one facet of mountain biodiversity, offering opportunities for study and insights into global climate and landscape change issues.