Recovery of species richness lags behind functional recovery in restored grasslands

Abstract

Restoration of grasslands on abandoned croplands is a major opportunity for land development in degraded landscapes. In this study, we compared the success of three restoration measures, spontaneous recovery, perennial‐crop–mediated restoration, and sowing native grasses, by using a unique combination of species‐based and trait‐based approaches. We sampled 373 4‐m2 plots in nearly 1,000 ha of 20‐year‐old–restored grasslands and 72 4‐m2 plots in three neighbouring ancient grasslands. Species richness and target species cover were higher in spontaneously recovered sites than in other restored sites, but reference sites had higher scores than all restored sites. Spontaneous sites had higher functional diversity than the other restored sites. Spontaneous and reference sites showed little difference in their functional diversity and in the community‐weighted means of relevant traits. Our findings indicate that the establishment limitation effect of the initial application of perennial crops or sowing competitive grasses can last for decades, hindering the recolonization of target species and the recovery of functional diversity; thus, they should be applied in landscapes with high cover of natural habitats only when inhibiting undesirable species is of paramount importance. The similar levels of functional niche saturation in spontaneous and reference sites may also indicate a self‐developed establishment‐limited situation after 20 years of succession. In combination with this, the lagging recovery of species richness entails lower functional redundancy in spontaneous sites. Our results underline the necessity of postrestorative management methods that reduce establishment limitation and contribute to the recolonization and subsequent coexistence of functionally similar species.

Grazing livestock increases both vegetation and seed bank diversity in remnant and restored grasslands

“…This is also supported by our findings, as the number of species without specific biotic vectors dominated in the grasslands and the specialist species richness was limited by the distance between grassland origins. The latter mechanism implies that grassland species are dispersal‐limited but that they are strongly dependent on grazing animals improving local conditions, holding competitive species in check and facilitating re‐establishment (Tölgyesi et al, 2019).…”

How climate, topography, soils, herbivores, and fire control forest–grassland coexistence in the Eurasian forest‐steppe

“…Fortunately, a growing body of information on the ecology of community reassembly and best management practices is leading to growth in grassland restoration (e.g. Kämpf et al ., 2016 ; Török et al ., 2018 ; Tölgyesi et al ., 2019 ). By contrast, restoration of natural forests in the forest‐steppe is rare, due to a focus on commercial tree plantations and intensive rotational forestry throughout the entire region (Cao, 2008 ; Erdős et al ., 2018 a ).…”

Impact of Land Use Changes on the Diversity and Conservation Status of the Vegetation of Mountain Grasslands (Polish Carpathians)

“…However, many types of grasslands with high natural value, such as the mesic grasslands occurring in the study area, have developed and currently exist due to a proper mowing regime [63]. Plant diversity and conservation status largely depend on diversified land use, as revealed by the studies of Kun et al [64] carried out in the Romanian Carpathians and Tölgyesi et al [65] in Hungary. Hence, the preservation of the mosaic spatial structure of natural and semi-natural features and extensive farming practices in connection with diverse forms of human impact, such as grazing and mowing, is the optimal solution to preserve diversity at the levels of species, community, and landscape in mountain areas.…”