Determining the role of dew in an alpine meadow in northeastern
Qinghai-Tibet Plateau using hydrogen-oxygen isotope method
Abstract
Dew is closely related to the micro-use of water and to large-scale
hydrological processes. Dew formation on grasslands plays a particularly
vital role in maintaining the ecohydrological cycle. Stable isotope
information for dew, ambient water vapor, soil water, plant water, creek
water, and precipitation were tracked to determine the role of dew in
ecohydrological processes in the meadow. The structural equation
modeling was used to investigate how environmental factors affect dew
formation. The Mix SIAR model in R was used to determine the source of
dew, and explore the dew transport route of six species of the
graminoid-Kobresia meadow in an alpine graminoid-Kobresia meadow in
northern Qinghai-Tibet Plateau. Our results showed that the amounts of
dew ranged from 0.002 mm to 0.22 mm, the frequency of dew was
42.86%-45.83% during summer in 2020 and 2021. Both atmospheric
pressure and temperature showed significant positive effects on dew
formation, while wind speed had a negative effect. Evapotranspiration
indirectly affected dew formation. The contribution rates of soil water,
plant water, and ambient water vapor to dew formation were 48.20±5.46%,
38.30±5.07%, and 13.50±1.82%, respectively. The proportion of dew
utilization by graminoid and Kobresia species showed no significant
species differences. Our statistical analysis determines the role of dew
in an alpine graminoid-Kobresia meadow in the northern Qinghai-Tibet
Plateau, which provides an improved understanding of dew formation based
on a stable isotope technology.