Plant functional trait change across a warming tundra biome

Abstract

Plant functional trait change across a warming tundra biomeThe tundra is warming more rapidly than any other biome on Earth, and the potential ramifications are far-reaching because of global feedback effects between vegetation and climate. A better understanding of how environmental factors shape plant structure and function is crucial for predicting the consequences of environmental change for ecosystem functioning. Here we explore the biome-wide relationships between temperature, moisture and seven key plant functional traits both across space and over three decades of warming at 117 tundra locations. Spatial temperature-trait relationships were generally strong but soil moisture had a marked influence on the strength and direction of these relationships, highlighting the potentially important influence of changes in water availability on future trait shifts in tundra plant communities. Community height increased with warming across all sites over the past three decades, but other traits lagged far behind predicted rates of change. Our findings highlight the challenge of using space-for-time substitution to predict the functional consequences of future warming and suggest that functions that are tied closely to plant height will experience the most rapid change. They also reveal the strength with which environmental factors shape biotic communities at the coldest extremes of the planet and will help to improve projections of functional changes in tundra ecosystems with climate warming. Environment-trait relationships across the tundra biomeWe found strong spatial associations between temperature and community height, SLA and LDMC (Fig. 2a, Extended Data Fig. 2 and Supplementary Table 3) across the 117 survey sites. Both height and SLA increased with summer temperature, but the temperaturetrait relationship for SLA was much stronger at wetter than at drier sites. LDMC was negatively related to temperature, and

Plant physical and chemical traits associated with herbivory in situ and under a warming treatment

“…Hudson et al () found that most species showed increased leaf size and plant height under a warming treatment and that traits related to growth were more affected by warming than leaf nitrogen content. Similarly, Bjorkman et al () found comparable intraspecific responses of plant traits, such as plant height, LA and SLA, to temperature gradients.…”

“…While LA tended to increase across all plant species (+19.6% on average), this shift likely resulted from a modification of resource allocation driven by changes in SLA, such as an expansion of the foliar lamina associated with a decrease in leaf thickness. Hence, higher temperature likely enhances plant metabolism, favouring higher rates of cell expansion and facilitating faster production of softer tissues (Atkin, Botman, & Lambers, ; Körner, ); temperature is thus generally positively related to SLA at the intra‐ and interspecific level (Bjorkman et al, ; Woodward, ). Hudson et al () found that most species showed increased leaf size and plant height under a warming treatment and that traits related to growth were more affected by warming than leaf nitrogen content.…”

Human eutrophication drives biogeographic salt marsh productivity patterns in China

“…In a manipulative experiment in a salt marsh in Georgia, USA, Dai and Wiegert () have shown that the productivity of S. alterniflora significantly increases after N addition, and that 79% of this increment is explained by leaf area, while just 21% is explained by leaf N. These results suggest that, in salt marshes, size‐related traits are more sensitive to geographic variation in exogenous nutrient inputs than leaf economic traits (e.g., SLA, leaf N and P) (Bjorkman et al. ). These size‐related traits potentially play a significant role in conferring a competitive advantage.…”

Plant traits inform predictions of tundra responses to global change

“…This ‘traits manifesto’ (Reich, ) has seen a dramatic rise in popularity in recent years, improving our understanding of community assembly (Siefert et al ., ) and ecosystem responses to warming (Soudzilovskaia et al ., ). However, progress is hampered by fundamental unknowns regarding the nature of trait variation and physiological tradeoffs (Siefert et al ., ; Díaz et al ., ; Shipley et al ., ), by issues of prediction across scales (Messier et al ., ), and by uneven data coverage among traits, species, and ecosystems (Iversen et al ., ; Jetz et al ., ; Bjorkman et al ., ,b). For trait‐based ecology to reach its full potential, trait–function relationships must be tested across the world's biomes, including in our planet's most extreme environments.…”