Climate sensitivity functions and net primary production: A framework for incorporating climate mean and variability

Abstract

Understanding controls on net primary production (NPP) has been a long-standing goal in ecology. Climate is a well-known control on NPP, although the temporal differences among years within a site are often weaker than the spatial pattern of differences across sites. Climate sensitivity functions describe the relationship between an ecological response (e.g., NPP) and both the mean and variance of its climate driver (e.g., aridity index), providing a novel framework for understanding how climate trends in both mean and variance vary with NPP over time. Nonlinearities in these functions predict whether an increase in climate variance will have a positive effect (convex nonlinearity) or negative effect (concave nonlinearity) on NPP. The influence of climate variance may be particularly intense at ecosystem transition zones, if species reach physiological thresholds that create nonlinearities at these ecotones. Long-term data collected at the confluence of three dryland ecosystems in central New Mexico revealed that each ecosystem exhibited a unique climate sensitivity function that was consistent with long-term vegetation change occurring at their ecotones. Our analysis suggests that rising temperatures in drylands could alter the nonlinearities that determine the relative costs and benefits of variance in precipitation for primary production.

Nitrogen deposition magnifies the sensitivity of desert steppe plant communities to large changes in precipitation

“…Overall, we proposed an integration that drives ANPP as a consequence of plant community shift mainly by precipitation changes (Figure ). Additionally, as previously mentioned, the distinguishing ecosystem community responses to climate extremes, if the responses agree with the ecological adaptive theory, might be mainly due to the high degrees of heterogeneity in these ecosystems’ resistance and resilience or sensitivity to the magnitude, duration or timing of a climate driver alone and multifactor interactions (Bai et al, ; De Boeck et al, ; Rudgers et al, ; Smith et al, ). These aspects need to be explored further.…”

Semiarid ecosystem sensitivity to precipitation extremes: weak evidence for vegetation constraints

“…Within dryland ecosystems, there is growing evidence that increasing PPT variability is occurring despite rising mean aridity (Rudgers et al. ), with attendant negative impacts to key ecosystem services such as carbon uptake (Liu et al. ), forage, and livestock productivity linked to increased PPT variability (Sloat et al.…”

“…Specifically, gradual warming is expected to increase the frequency of wet and dry years (Swain et al 2018), PPT extremes such as severe drought (Cook et al 2015), and extreme PPT events (Prein et al 2017) as the water-holding capacity of the atmosphere increases and the water cycle intensifies (Huntington 2006, IPCC 2013. Within dryland ecosystems, there is growing evidence that increasing PPT variability is occurring despite rising mean aridity (Rudgers et al 2018), with attendant negative impacts to key ecosystem services such as carbon uptake , forage, and livestock productivity linked to increased PPT variability (Sloat et al 2018). Because water-limited semiarid regions are particularly vulnerable to future PPT changes, a pressing need has emerged to predict how these regions will respond to forecast changes in PPT, as this has implications for future ecosystem dynamics that now extend from local to global scales (Poulter et al 2014, Ahlstrom et al 2015, Haverd et al 2016.…”

The competitive advantage of a constitutive CAM species over a C4 grass species under drought and CO2 enrichment

“…, Reyes‐García and Andrade ) and evidence shows that the climate is becoming more arid in this region (Rudgers et al. ). The ability to store water and tolerate drought is a well‐known characteristic of most CAM species (Lüttge , Borland et al.…”