Abstract:
The Chir-Pine (Pinus roxburghii) and
Banj-Oak (Quercus leucotrichophora)-dominated
ecosystems of central Himalaya provide signifcant
green services. However, responses of these ecosystems, with respect to ecosystem carbon fux variability, to changing microclimate are not yet studied. Since quantifcation of ecosystem responses to
fuctuation in the microclimate, particularly rainfall, is expected to be benefcial for management of
these ecosystems, this study aims (i) to quantify and
compare amplitude of rainfall-induced change in
the carbon fuxes of Chir-Pine and Banj-Oak-dominated ecosystems using wavelet methods, and (ii)
to quantify and compare dissimilarities in the ecosystem exchanges due to varying rainfall spell and
amount. Eddy covariance–based continuous daily
micrometeorological and fux data, during the 2016–
2017 monsoon seasons (total 244 days, 122 days of
June–September), from two sites in Uttarakhand,
India, are used for this purpose. We fnd that both
Chir-Pine and Banj-Oak-dominated ecosystems are
the sinks of carbon, and Chir-Pine-dominated ecosystem sequesters around 1.8 times higher carbon
than the Banj-Oak. A systematic enhancement in the
carbon assimilation of the Chir-Pine-dominated ecosystem is noted with increasing rainfall spell following a statistically signifcant power-law relationship.
We have also identifed a rainfall amount threshold
for Chir-Pine and Banj-Oak-dominated ecosystems
(10±0.7 and 17±1.2 mm, respectively) that resulted
in highest ecosystem carbon assimilation in monsoon.
The general inference of this study accentuates that
Banj-Oak-dominated ecosystem is more sensitive to
maximum rain within a spell whereas the Chir-Pinedominated ecosystem is more responsive to increasing rainfall spell duration.
