Temporal continuity and adjacent land use exert different effects on richness of grassland specialists and alien plants in semi‐natural grassland

Abstract

AbstractAimsGrassland plant species diversity is affected by local, temporal and landscape environmental factors, but what is the relative importance of those factors? Understanding this is crucial for the effective conservation of grassland vegetation. We analyzed the factors affecting species richness to contribute to native species conservation and alien species management in grassland vegetation.LocationSemi‐natural grasslands in Shiroi City, Chiba Prefecture, Japan.MethodsThe species composition in 36 grasslands was surveyed in 2014. Plants were classified as native grassland specialist, other native or alien species. Generalized Linear Models (GLM) were developed, with the number of species in each plant type as the response variable and local (habitat area, use of mowing management), landscape (adjacent land use, connectivity to other grassland habitats) and temporal (period for which the grassland has been preserved from development, i.e., temporal continuity) factors as explanatory variables. Other GLM were developed with the presence/absence of each species as a response variable and three factors as explanatory variables.ResultsHabitat area, use of mowing management and temporal continuity were most important in explaining the number of grassland specialist species and had significant positive effects on their richness. Species‐based analysis identified a significant positive effect of temporal continuity on grassland specialist species. By contrast, habitat area and adjacent land use were most related to alien species richness. The number of alien species was high in grasslands adjacent to farmlands or roads.ConclusionsThe relative importance of temporal and spatial factors differs between native grassland specialists and alien species. Mowing is effective for the conservation of grassland specialists’ species diversity, particularly in historically old grasslands. However, it is necessary to pay attention to the invasion of alien species from adjacent residential or agricultural areas.