Functional Trait Changes, Productivity Shifts and Vegetation Stability in Mountain Grasslands during a Short-Term Warming

Abstract

Plant functional traits underlie vegetation responses to environmental changes such as global warming, and consequently influence ecosystem processes. While most of the existing studies focus on the effect of warming only on species diversity and productivity, we further investigated (i) how the structure of community plant functional traits in temperate grasslands respond to experimental warming, and (ii) whether species and functional diversity contribute to a greater stability of grasslands, in terms of vegetation composition and productivity. Intact vegetation turves were extracted from temperate subalpine grassland (highland) in the Eastern Pyrenees and transplanted into a warm continental, experimental site in Lleida, in Western Catalonia (lowland). The impacts of simulated warming on plant production and diversity, functional trait structure, and vegetation compositional stability were assessed. We observed an increase in biomass and a reduction in species and functional diversity under short-term warming. The functional structure of the grassland communities changed significantly, in terms of functional diversity and community-weighted means (CWM) for several traits. Acquisitive and fast-growing species with higher SLA, early flowering, erect growth habit, and rhizomatous strategy became dominant in the lowland. Productivity was significantly positively related to species, and to a lower extent, functional diversity, but productivity and stability after warming were more dependent on trait composition (CWM) than on diversity. The turves with more acquisitive species before warming changed less in composition after warming. Results suggest that (i) the short-term warming can lead to the dominance of acquisitive fast growing species over conservative species, thus reducing species richness, and (ii) the functional traits structure in grassland communities had a greater influence on the productivity and stability of the community under short-term warming, compared to diversity effects. In summary, short-term climate warming can greatly alter vegetation functional structure and its relation to productivity.

Variability in community productivity—mediating effects of vegetation attributes

“…Pfestorf et al. () and Debouk, de Bello, and Sebastià () both reported finding a more direct coupling between environmental drivers and plant functional traits than diversity. Aggregate ANPP in our study was stabilized through time by attributes linked to species identity and dominance rather than by species richness.…”

“…On the other hand, Wilcox et al (2017) found no correlation between the mean of species diversity of patches and temporal variability at either the patch or aggregate scales in an analysis of data from 62 plant communities. Pfestorf et al (2013) and Debouk, de Bello, and Sebastià (2015) both reported finding a more direct coupling between environmental drivers and plant functional traits than diversity. Aggregate ANPP in our study was stabilized through time by attributes linked to species identity and dominance rather than by species richness.…”

How Plant Functional Traits of Dominant Species Respond to Fencing and Water-Nitrogen Addition in Horqin Grassland, China

“…Because nitrogen is one of the important resources for plants to grow [33,34], and N addition can improve soil nitrogen availability which promotes the photosynthesis of plants [10,35]. Additionally, SLA was positively correlated with plant growth rates and reflected light capture and plant growth [36], and high SLA suggests that plants have a strong ability to maintain nutrition [14,37]. N supply promotes the photosynthesis of plants and results in high SLA, and accordingly low LDMC was observed.…”

“…Plant functional traits are important in ecology, because they can respond to changes in environmental conditions at the individual level and also affect ecosystem structure and function [13,14]. Recently, plant functional traits have been documented in response to climate changes [15] and grazing [16,17].…”

The positive effect of biodiversity : Using root traits to understand effects of plant diversity and drought on grassland productivity

“…A (meteorological) drought, i.e. a period with below average precipitation, often accompanied by high atmospheric vapour pressure deficits (Dai, 2011), typically results in low water availability in the soil, limiting plant growth and affecting plant interactions and vegetation structure (Morecroft et al, 2004, Debouk et al, 2015. Previous summer droughts have been shown to reduce ecosystem productivity throughout Europe (Ciais et al, 2005) and they are predicted to increase in Central and Southern Europe in the next decades, with up to 40% less precipitation in summer in 2071-2100 (Dankers and Hiederer, 2008) (Fig.…”