Recovery of Mediterranean steppe vegetation after cultivation: Legacy effects on plant composition, soil properties and functional traits

Abstract

Questions: Are the vegetation structure and soil properties of fallows similar to adjacent species-rich Mediterranean steppe communities 35 years after abandonment? Is there a spontaneous redevelopment towards the original steppe vegetation after reintroduction of the traditional grazing system? Can differences in functional trait composition be identified according to different land-use types? Do traits of selected species affect the ability to recolonize fallow land? Location: Mediterranean steppe of La Crau (Southeastern France). Methods: We conducted 80 vegetation surveys and soil analyses in the steppe and adjacent fallow land in six locations in La Crau in 2015; for three locations, data from 2001 were included. To compare the functional composition of steppe vs fallow land, community-weighted means (CMW) of specific leaf area (SLA), leaf dry matter content (LDMC) and canopy height were calculated. To test whether trait variability is associated with the recolonization success of 12 selected target species, we measured SLA, LDMC, canopy height, plant width and aboveground biomass on eight replicate individuals per site and species.Results: Fallow land was characterized by lower species richness and elevated phosphorus and potassium content in the soil. Comparing vegetation relevés between 2001 and 2015 revealed that the fallows were developing towards steppe vegetation. CWMs of SLA were significantly lower and CWM of LDMC higher in steppe than in fallow land. There was no similarity in trait composition between steppe species that successfully recolonized the fallow-land community, and no evidence that intraspecific trait variability is associated with recolonization success of these species. K E Y W O R D S community trait means, cultivation, dry grassland, grazing, intraspecific trait variability, leaf dry matter content, natural recovery, restoration, specific leaf area | 75 Applied Vegetation Science HELM Et aL.

Plant intraspecific functional trait variation is related to within‐habitat heterogeneity and genetic diversity inTrifolium montanumL.

“…However, axes (traits) sometimes have to be reduced to follow recommendations about the ratio between observations and number of dimensions and orthogonality among traits (e.g., to four axes, see Benavides, Scherer‐Lorenzen, & Valladares, 2019). The “iFD CV ” method used herein is a trait‐by‐trait approach simply incorporating individual trait variation based on population‐wise coefficients of variation (CVs) within a species (see, e.g., Helm et al, 2019). We ensured the absence of collinearity among functional traits (see above), and thus, there was no further need to do axes (trait) reductions like in hypervolume approaches.…”

“…We assessed population‐wise iFD CV as the mean CV of RH (CV RH ), AGB (CV AGB ), LA (CV LA ), SLA (CV SLA ), LDMC (CV LDMC ), F v / F m (CV Fv/Fm ), PI (CV PI ), SPS (CV SPS ), and SPI (CV SPI ; Tables 1 and 2; see also Helm et al, 2019 for CV functional trait calculation).…”

Grazing effects on intraspecific trait variability vary with changing precipitation patterns in Mongolian rangelands

“…The missing overall pattern of trait responses, but the high responsiveness of the traits in general (Table S2) traits to an environmental gradient (Helm et al, 2019). Additionally, a given species' performance at large scales (i.e., along the precipitation gradient) depends also on its local distribution pattern and natural selection patterns across the gradient.…”

Key issues in Northwestern Mediterranean dry grassland restoration

“…After major soil disturbance (e.g. road construction, quarries, pipeline laying), Mediterranean grassland recovery may be very slow (Römermann et al 2005; Pueyo et al 2009; Coiffait‐Gombault et al 2011; Helm et al 2019). While finding commercial seed sources of local Mediterranean species is still a challenge, soil transfer, as loose soil or as turf, has already produced encouraging results, at least over shorttime periods, as compared to other ecological restoration techniques (e.g.…”