Determining the dew characteristics and sources in an alpine meadow of
northeastern Qinghai-Tibet Plateau using hydrogen-oxygen isotope
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, however, its
characteristics and sources were rarely reported. Here, stable isotope
for dew, ambient water vapor, soil water, plant water, creek water, and
precipitation were tracked to determine the characteristics of dew from
ecohydrological processes in the meadow. The structural equation model
was used to investigate how environmental factors affect dew formation.
The Mix SIAR model in R was used to determine the sources 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
annual amount was about 37.92 ± 1.03 mm, acounting for 7.13% of
precipitation. 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, the mean value was 10.5±3.8%. 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.