Global variability in leaf respiration in relation to climate, plant functional types and leaf traits

Abstract

SummaryLeaf dark respiration (R dark ) is an important yet poorly quantified component of the global carbon cycle. Given this, we analyzed a new global database of R dark and associated leaf traits. Data for 899 species were compiled from 100 sites (from the Arctic to the tropics). Several woody and nonwoody plant functional types (PFTs) were represented. Mixed-effects models were used to disentangle sources of variation in R dark .Area-based R dark at the prevailing average daily growth temperature (T) of each site increased only twofold from the Arctic to the tropics, despite a 20°C increase in growing T (8-28°C). By contrast, R dark at a standard T (25°C, R dark 25 ) was threefold higher in the Arctic than in the tropics, and twofold higher at arid than at mesic sites. Species and PFTs at cold sites exhibited higher R dark 25 at a given photosynthetic capacity (V cmax 25 ) or leaf nitrogen concentration ([N]) than species at warmer sites. R dark 25 values at any given V cmax 25 or [N] were higher in herbs than in woody plants.The results highlight variation in R dark among species and across global gradients in T and aridity. In addition to their ecological significance, the results provide a framework for improving representation of R dark in terrestrial biosphere models (TBMs) and associated land-surface components of Earth system models (ESMs).

Mapping local and global variability in plant trait distributions

“…The traits studied here-SLA, Nm , and Pm -are central to predicting variation in rates of plant photosynthesis (5, 6, 9, 11) and foliar respiration (10,36). The importance of these traits and the more advanced representation of functional diversity developed here may be used to better capture the response of the land surface component of the Earth system to environmental change.…”

“…Multiple traits are critical to both photosynthesis and respiration, foremost leaf nitrogen concentration (Nm ) and specific leaf area (SLA) (5-7). More recently, variation in leaf phosphorus concentration (Pm ) has also been linked to variation in photosynthesis and foliar respiration (7)(8)(9)(10)(11)(12). Estimating detailed global geographic patterns of these traits and corresponding trait-environment relationships has been hampered by limited measurements (13), but recent improvements in data coverage (14) allow for greater detail in spatial estimates of these key traits.…”

Climate pattern-scaling set for an ensemble of 22 GCMs – adding uncertainty to the IMOGEN version 2.0 impact system

“…This is a major noted deficiency in current large-scale terrestrial models (Booth et al, 2012;Huntingford et al, 2013b;Smith and Dukes, 2013). In addition, the assessment of a newly available enhanced description of leaf dark respiration (Atkin et al, 2015) is needed, as well as the inclusion of both nitrogen and phosphorus constraints to plant productivity in tropical ecosystems (e.g. Mercado et al, 2011), and inclusion of a full representation of a coupled carbon-nitrogen cycle in JULES (Zaehle et al, 2010).…”

The decadal state of the terrestrial carbon cycle: Global retrievals of terrestrial carbon allocation, pools, and residence times

“…The complex response of terrestrial ecosystem CO 2 exchanges to short-and long-term changes in temperature, water availability, nutrient availability, and rising atmospheric CO 2 (2-6) remains highly uncertain in C cycle model projections (7). As a result, there are large gaps in our understanding of terrestrial C dynamics, including the magnitude and residence times of the major ecosystem C pools (8,9) and rates of autotrophic respiration (10). Moreover, the impact of climatic extremes on C cycling, such as recent Amazon droughts (11), highlights the importance of understanding the terrestrial C cycle sensitivity to climate variability.…”