The functional role and diversity of soil nematodes are stronger at high
elevation in the lesser Himalayan mountain ranges
Abstract
Soil nematodes are a foremost component of terrestrial biodiversity,
they display the whole gamut of trophic guilds and life strategies, and
by their activity, affect major ecosystem processes, such as organic
matter degradation and carbon cycling. Based on nematodes’ functional
types, nematode community indices have been developed and can be used to
link variation in nematode community composition and ecosystem
processes. Yet, the use of these indices has been mainly restricted to
anthropogenic stresses. In this study, we propose to expand the use of
nematodes’ derived ecological indices to link soil and climate
properties with soil food webs, and ecosystem processes that all vary
along steep elevation gradients. For this purpose, we explored how
elevation affects the trophic and functional diversity of nematode
communities sampled every 300 m, from about 1000 m to 3700 m above sea
level, across four transects in the lesser Himalayan range of Jammu and
Kashmir. We found that (1) the trophic and functional diversity of
nematodes increases with elevation; (2) differences in nematodes
communities generate habitat-specific functional diversity; (3) the
sigma maturity index, the channel index, and the metabolic footprint of
nematodes increase with elevation, indicating less mature and less
productive ecosystems, enhanced fungal-based energy flow, and a
predominant role of nematodes in generating carbon influxes at high
elevation sites, respectively. We thus conclude that the functional
contribution of soil nematodes to belowground ecosystem processes,
including carbon and energy flow, is stronger at high elevation.
Overall, this study highlights the central importance of nematodes in
sustaining soil ecosystems and brings insights into their functional
role, particularly in alpine and arctic soils.