Disentangling the Effects of Disturbance from Those of Dominant Tall Grass Features in Driving the Functional Variation of Restored Grassland in a Sub-Mediterranean Context

Abstract

Land abandonment in sub-Mediterranean grasslands causes the spread of tall-grasses, affecting biodiversity and ecosystem functioning. Mowing allows the recovery of the coenological composition after invasion, but the mechanisms acting at the fine-scale are poorly investigated. Since 2010 in the Central Apennines, we fenced a grassland invaded by Brachypodium rupestre, divided it into two areas, half of each was mowed biyearly and half remained unmown. In 2017 we selected ten 20 × 20 cm experimental units per half-area, collecting data on species occurrences, plant traits, B. rupestre height and phytomass. We used generalized linear mixed-effect modelling to disentangle the role of mowing from the impact of B. rupestre features in driving the community functional variations. Mowing was the main driver in the recovery process, acting as an abiotic filter (enhancement of tolerance-avoidance strategies). Furthermore, the reduction of weaker competitor exclusion processes fostered the increase of functional variation between coexisting species. Both drivers acted on different plant traits (e.g., mowing on life span, vegetative propagation types and plant height, mowing and B. rupestre features on space occupation types, seed mass and leaf anatomy), generally enhancing the extent of functional strategies related to resource acquisition and storage, reproduction, space occupation and temporal niche exploitation.

From Remote Sensing to Species Distribution Modelling: An Integrated Workflow to Monitor Spreading Species in Key Grassland Habitats

“…The strong diffusion of B. genuense on habitat 6210* is probably due to the variation in the livestock types (from sheep to cows/horses) and/or the reduction of extensive grazing in the study area. The increase of Brachypodium (B. pinnatum, B. genuense, B. rupestre) distribution cause a reduction in grasslands biodiversity [31,33,92,107,108]. As shown in a recent study [109], when B. genuense and/or B. rupestre becomes dominant (cover > 80%), a substantial reduction in biodiversity was observed.…”

Exploring Assembly Trajectories of Abandoned Grasslands in Response to 10 Years of Mowing in Sub-Mediterranean Context

“…To understand the functional trajectory of the plant community induced by mowing twice a year, we selected a core of plant traits capturing different functional dimensions: competition for light and space occupation (plant vegetative height, H; horizontal architecture, HA) [52,53]; resource exploitation (specific leaf area, SLA; leaf dry matter content, LDMC) [53] and regulation of leaf temperature and water-use efficiency during photosynthesis (leaf area, LA) [53]; temporal niche exploitation (flowering phenology, FP; leaf phenology, LP) [27,52]; clonal strategy (clonal position, CP; clonal spread, CS) (adapted from [54]). Moreover, leaf traits (LA, SLA, and LDMC) were also used to calculate plant CSR (competitive, stress tolerant, and ruderal) strategies [39], by integrating both leaf economics (typical of S and R strategy selection) and leaf size (typical of the C strategy) variation spectra in a three-way trade-off [36].…”

“…Moreover, leaf traits (LA, SLA, and LDMC) were also used to calculate plant CSR (competitive, stress tolerant, and ruderal) strategies [39], by integrating both leaf economics (typical of S and R strategy selection) and leaf size (typical of the C strategy) variation spectra in a three-way trade-off [36]. These selected traits are related to both competitive ability and response to mowing [52][53][54][55]. A description of each trait and their respective list of states and data sources are reported in Table 1.…”

Practice Must Be Backed up by Theory! A Special Issue on Plant Community Ecology

“…In particular, Tordoni et al [3] suggested that functional niche divergence may foster community invasibility; resident native communities more susceptible to invasion are those which, on average, showed a combination of functional traits (higher resource acquisition capacity and lower drought resistance) coupled with an apparently reduced water-use efficiency. In a similar way, land-use change can trigger processes that transform the landscape [17]: land abandonment in sub-Mediterranean grasslands causes the spread of native tall-grasses, affecting biodiversity and ecosystem functioning [19]. At a fine scale, mowing is used to allow the recovery of the coenological composition after invasion, acting as an abiotic filter (enhancement of tolerance-avoidance strategies); the reduction of weaker competitors increases the functional variation between coexisting species.…”

“…At a fine scale, mowing is used to allow the recovery of the coenological composition after invasion, acting as an abiotic filter (enhancement of tolerance-avoidance strategies); the reduction of weaker competitors increases the functional variation between coexisting species. Understanding the mechanism that enhances the extent of functional strategies related to resource acquisition and storage, reproduction, space occupation, and temporal niche exploitation [19][20][21] can help us to answer global challenges.…”