Impact of temporal precipitation variability on ecosystem productivity

Abstract

Projected increases in temporal precipitation variability, including intra‐annual and interannual variability, will likely have important impacts on terrestrial ecosystem productivity. The direction and magnitude of these impacts and how they vary across biomes, however, remain largely uncertain. Here, we review published literature that investigated the effect of different characteristics of temporal precipitation variability on vegetation productivity. We first reviewed commonly used methods, including manipulation experiments, process‐based modeling, and data‐driven analysis, and further discussed their strengths and limitations. Then, we summarized state‐of‐the‐art research on this topic by categorizing the results based on the characteristics of temporal precipitation variability. Given the same amount of growing season precipitation, a more extreme precipitation regime, characterized as fewer but larger precipitation events, tends to have a negative impact on vegetation productivity of most ecosystems except xeric grasslands and wet‐cold forests. Precipitation in the early growing season was found to be particularly important to vegetation productivity. Greater interannual precipitation variability tends to decrease vegetation productivity, but the reported patterns are complex, as both concave‐up and concave‐down precipitation‐productivity relations were found. Despite the progress made so far, critical challenges and knowledge gaps remain, such as the global‐scale impacts across different biomes, the role of biological adaption, and the contribution of individual precipitation events. Future research needs to combine manipulation experiments across a broad spectrum of ecosystem types and environmental gradients with model‐data integration strategies to disentangle the interactions between abiotic and biotic factors controlling vegetation responses to precipitation variability. This article is categorized under: Science of Water > Hydrological Processes Water and Life > Nature of Freshwater Ecosystems

Divergent responses of primary production to increasing precipitation variability in global drylands

“…Since our TECO model is an ecosystem model with climate, soil type, and vegetation type set according to the dryland selected for calibration, the above inferences are restricted to drylands with similar environmental conditions and ecosystem properties. Our inferences may be also applicable to other drylands, if MAP is the main predictor of the effect of precipitation variability on ANPP, as suggested in some previous studies (Gherardi & Sala, 2019;Liu et al, 2020). Whether and how MAT, soil type, and vegetation type (indexed by leaf V cmax and soil-profile root distribution) would modulate the effect of precipitation variability on ANPP were explored as our fourth modeling purpose by changing these site properties in our TECO model.…”

“…Precipitation has become increasingly variable in the past century and will become more so in the coming decades due to climate warming (Seneviratne et al, 2012; Stocker, 2013). This increased variability can affect ecosystem services such as primary production (Gherardi & Sala, 2019; Hsu et al, 2012; Knapp et al, 2008; Liu et al, 2020; Seneviratne et al, 2012), and can also drive state change in alternative stable state systems (Borgogno et al, 2007; Chen et al, 2018). Drylands are among the most sensitive ecosystems to precipitation variability globally (Ahlström et al, 2015; Gherardi & Sala, 2019; Haverd et al, 2017).…”

“…The effect of precipitation variability on primary production has been increasingly investigated during the past two decades, but mostly at intra-annual time scales (i.e., the event size or seasonality of precipitation) (Heisler-White et al, 2009;Knapp et al, 2002Knapp et al, , 2008Liu et al, 2020;Meng et al, 2021;Thomey et al, 2011) and much less at interannual time scales (i.e., year-to-year variation) (Gherardi & Sala, 2019;Haverd et al, 2017;Liu et al, 2020;Rudgers et al, 2018). Theory, manipulative experiments, and observations all generally suggest a positive effect of intra-annual precipitation variability on aboveground net primary production (ANPP) in xeric ecosystems and a negative effect in mesic ecosystems, with a mean annual precipitation (MAP) threshold between 300 and 650 mm year −1 (Heisler- White et al, 2008White et al, , 2009Knapp et al, 2002Knapp et al, , 2008Liu et al, 2020;Thomey et al, 2011). Recently, Gherardi and Sala (2019) estimated the effect of interannual precipitation variability on ANPP as the slope of the regression line between the mean of ANPP and the coefficient of variation (CV) of annual precipitation in 5-year moving windows at 43 globally distributed sites, where long-term ANPP observations were available.…”

“…In addition to MAP, the effect of precipitation variability on ANPP may be also modulated by MAT, soil type, vegetation type, as well as the variability patterns (i.e., magnitude, duration, and stochasticity) and antecedent effects of precipitation (Felton et al, 2021;Liu et al, 2020;Rudgers et al, 2018;Sala et al, 2012).…”

“…For example, an ecosystem with high MAT loses more water from surface soil through evaporation, and therefore may benefit more from the percolation of large precipitation events to deep soil than an ecosystem with lower MAT where evaporation is less (Liu et al, 2020). Sandy soils facilitate infiltration and therefore may benefit more from increased precipitation variability under low MAP, but can lose more water under high MAP due to lower water holding capacity, in comparison to loamy or clay soils (Sala et al, 1988(Sala et al, , 2015.…”