Constructing a database of alien plants in the Himalaya to test patterns structuring diversity.

Area of Science:

• Ecology
• Botany
• Biogeography

Background:

• Alien plant species distributions are influenced by climate, human activity, and introduction pathways.
• Understanding these factors is crucial for managing invasive species in diverse ecosystems like the Himalayas.

Purpose of the Study:

• To investigate the drivers of alien plant species richness in the Himalayan region.
• To compare alien and native species patterns within a phylogenetic framework.

Main Methods:

• Compiled a comprehensive database of alien plant distributions across the Himalayas.
• Analyzed richness patterns, phylogenetic clustering, and geographic/climatic affinities in Jammu & Kashmir and Bhutan.
• Compared alien and native species richness and distribution patterns across elevational gradients.

Main Results:

• Documented 1470 alien species, with ~600 naturalized, comprising 14% of Himalayan vascular plants.
• Alien species richness declined with elevation, with high-elevation species being a subset of low-elevation flora, indicating introduction site importance.
• Native and alien species richness positively correlated with elevation, suggesting climate and productivity as key factors.

Conclusions:

• Alien plant richness in the Himalayas is primarily shaped by introduction location and climatic factors, not human disturbance or native species abundance.
• Ongoing expansion of invasive alien species from low-elevation introduction points is occurring.