Grassland restoration on former arable land: Fine‐scale grass accumulation and damaged soil conditions limit species establishment

Abstract

Question: Which vegetation and soil parameters limit species establishment in restored grasslands? Do these parameters operate predominantly on a fine or a community scale?Location: White Carpathian Mountains, SE Czech Republic. Methods:We compared 16 grasslands restored on former arable land with 9 wellpreserved reference grasslands. We sampled cover of plant species in plots of 2 m × 2 m (community scale) in which four 20 cm × 20 cm subplots (fine scale) were nested. We quantified fine-scale heterogeneity as the mean Sørensen dissimilarity index among the species composition of the subplots. To characterize site conditions, we analyzed soil properties, above-ground plant biomass and its nutrient content. Results:Restored grasslands had a lower number of plant species at both the community and fine scales. Species number at the community scale was positively associated with the species number at the fine scale (irrespective of grassland type), but was not associated with fine-scale heterogeneity. This indicates the importance of fine-scale biotic interactions for overall species diversity. In support of this, in both grassland types, the species number was negatively associated with the cover of grasses, but only at the fine scale. Total cover (but not the biomass) was lower in restored grasslands, and was positively related with species number, particularly in restored grasslands. This indicates that the lower species number in the restored grasslands mainly resulted from deteriorated abiotic conditions. Such deterioration of the plant environment can be attributed particularly to the soil of the restored, formerly plowed grasslands. They had a lower soil organic matter content and a higher proportion of fine soil particles (silt and clay), indicating reduced soil water availability. The lower soil N content of restored grasslands was also reflected in the nutrient content of plant biomass, where lower N:P and N:K ratios indicated a limitation of plant growth by N-supply. Conclusion:The species number was generally driven by fine-scale biotic interactions, which operated similarly in both grassland types. The reduced number of plant

Standing and shed litters alter plant growth in disturbed and undisturbed soils differently

“…We used different soils, but they were of the same type. One soil type was long‐term stable, the other one was disturbed by former tillage (Mudrák et al., 2022). Despite that, plant species considerably modified the parameters of the microbial community in ancient grassland soil while they modified mainly chemical parameters in restored grassland soil.…”

“…Ancient grassland soils contained a higher amount of organic matter but were generally nutrient poor, while restored grassland soils were rich in P and K. Restored grassland soils were however deficient in N, likely due to their low content of organic matter (Klein‐Raufhake et al., 2022; Mudrák, Jongepierová, et al., 2023). Both of these grasslands therefore host similar plant community, historically did not differed in soil type, but recently differ in important soil properties as the restored grassland soil was disturbed by former tillage (Mudrák et al., 2022).…”

“…We also hypothesise that the direct effects of plant species will be stronger in restored than ancient grassland soil due to a shorter legacy of previous plant-soil interactions. community, historically did not differed in soil type, but recently differ in important soil properties as the restored grassland soil was disturbed by former tillage (Mudrák et al, 2022).…”

Large‐scale restoration of species‐rich dry grasslands on arable land: Environmental filtering drives successful species establishment over a period of 10 years

“…Trait convergence indicating environmental filtering was the most common pattern of within‐community functional diversity. Species co‐occurring in the community of one grassland were similar in their functional traits likely because of the strong filtering effect of mowing and due to the specific environmental conditions of both restored and permanent grasslands (Grime, 2006; Klein‐Raufhake et al, 2022; Mudrák et al, 2022). A similar result was found also in other studies examining grassland communities, particularly at broader spatial scales, which indicates that the pattern of environmental filtering is common in grassland communities (Barber et al, 2019; Mudrák et al, 2016; Scherrer et al, 2019).…”

“…Conversion of grasslands to arable land reduces the grassland connectivity and thus seed dispersion (Mudrák et al, 2022; Öster et al, 2009). During restoration, the high diversity of grasslands usually does not allow sowing of all target species for technical reasons.…”