Dependence of ecosystem carbon, nitrogen and phosphorus residence times
of mature forests in China on air temperature is segmented
Abstract
Ecosystem mean residence times of carbon, nitrogen and phosphorus
(τe,C, τe,N and τe,P,
respectively) are important ecosystem properties. By analyzing the
dependence of the observation-based estimates of τe,C,
τe,N and τe,P of 127 mature forests on
climate, vegetation, soil and terrain-related variables, we found that
climate, particularly mean annual minimum temperature
(Tmin), had the greatest influence on
τe,C, τe,N and τe,P.
Different from previous studies, we found that both τe,C
and τe,P increased with Tmin when
Tmin > 0 ℃. Despite a decreasing
phosphorus input with Tmin, vegetation adapted to
low phosphorus environment by increasing internal recycling and
phosphorus use efficiency, together with the increasing soil clay
content with Tmin, not the direct response to
Tmin, explained why both τe,C and
τe,P increased with Tmin when
Tmin > 0 ℃. Our results highlight
the importance of factors beyond climate in regulating residence times,
especially in subtropical forests.