Variability in community productivity—mediating effects of vegetation attributes

Abstract

Plant productivity varies through time in response to environmental fluctuations. Reducing variability in productivity requires an improved understanding of how plant community attributes interact with environmental fluctuations to influence plant growth dynamics. We evaluated links between two community attributes, species diversity and abundance‐weighted values of specific leaf area (SLA), and temporal variability in grassland productivity at patch (local) and aggregate (multipatch) spatial scales. Aggregate communities were created by combining patches of spatially distinct communities of perennial plant species from grassland biodiversity experiments in Texas, USA. Interannual variability in above‐ground net primary productivity (ANPP) of aggregate communities was analysed as a function of two multiplicative components, mean temporal variability in the ANPP of patches and temporal synchrony in ANPP dynamics among patches. We used regression analyses to determine whether temporal variability in aggregate ANPP and its components were correlated with either species diversity or community‐weighted SLA over 5 years. Temporal variability in ANPP of aggregate communities was strongly correlated with temporal variability in patch ANPP. Increasing mean SLA reduced ANPP variability of aggregate communities by increasing mean productivity. Increased temporal changes in patch‐scale SLA further reduced temporal variability in aggregate ANPP by reducing effects of precipitation fluctuations on productivity. Conversely, increasing species diversity over the narrow range measured increased temporal variability in aggregate ANPP. High diversity was associated with reduced dominance of temporally stable C4 grasses. Our results implicate means and patch‐scale temporal dynamics in community SLA as potential indicators of variability in grassland primary productivity through time. A http://onlinelibrary.wiley.com/doi/10.1111/1365-2435.13080/suppinfo is available for this article.

Nitrogen addition does not reduce the role of spatial asynchrony in stabilising grassland communities

“…4), including the N-induced loss in species asynchrony (Xu et al 2015;Zhang et al 2016a), and the loss of population stability due, partly, to reduced alpha diversity (Romanuk et al 2006;Yang et al 2012). Moreover, consistent with previous studies reporting that alpha stability largely contributed to gamma stability in naturally (Wilcox et al 2017) and experimentally (Polley & Wilsey 2018) assembled herbaceous communities, we also found that alpha stability more strongly influenced gamma stability than beta variability (Fig. 4).…”

“…Moreover, consistent with previous studies reporting that alpha stability largely contributed to gamma stability in naturally (Wilcox et al . ) and experimentally (Polley & Wilsey ) assembled herbaceous communities, we also found that alpha stability more strongly influenced gamma stability than beta variability (Fig. ).…”

“…On the one hand, the commonly observed negative impacts of N enrichment on alpha stability (see the previous paragraph) may translate into reduced gamma stability, especially in systems where alpha stability contributes dominantly to gamma stability, as reported by recent empirical studies (Wilcox et al . ; Polley & Wilsey ). On the other hand, there is uncertainty on how N enrichment influences spatial asynchrony among local communities.…”

Spectrally derived values of community leaf dry matter content link shifts in grassland composition with change in biomass production

“…Consistent with previous findings (e.g. Garnier et al 2004;Moretti et al 2013;Polley and Wilsey 2018), we predicted that inter-annual variation in precipitation would change both community LDMC (LDMC response) and the relationship between NDVI and LDMC (LDMC effect on NDVI).…”

“…The LDMC effect on spring NDVI of restored grassland was, by comparison to the LDMC response, conserved. The opposite was observed for relationships between production and community specific leaf area (SLA) of stands of perennial grass and forb species (Polley and Wilsey 2018). Inter-annual change in aboveground production (ANPP) of perennials resulted more from change in the trait effect on production (ANPP-SLA relationship) than trait response to precipitation.…”