In wet temperate regions, human activity has played an important role in shaping the size and distribution of grasslands. We examined change in land cover type and grassland area in a 9.2 × 22.3 km area of northern Chiba Prefecture, based on historical maps and documents for four time periods (1880s, 1950s, 1980s and 2000s). In the 1880s, conifer forests occupied the largest area (43.1%) amongst land cover types and grasslands accounted for 4.2% of the total area. However, literature available from the 1880s suggests that the understorey of conifer forests may have served as additional habitat for grasses. Thus, the habitat of grassland species is suggested to have covered up to 54% of the study area during this time period. By the 1950s, much of the grassland present in the 1880s had been changed to agricultural fields and paddies and grassland area had reduced to 2.9%. Residential development prior to and during the 1980s led to the conversion of forests and agricultural fields to grassland, increasing the grassland area to 11.6% of the study area. Finally, in the 2000s, grasslands had declined to 6.0% of the study area, likely due to conversion to residential areas. Despite these changes over time, 1.5% of the study area has remained as native forest or grassland for over 120 years. The spatial data presented herein are useful for conservation planning and studying the effect of historical land use change on biodiversity.

Aims Grassland 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. Location Semi‐natural grasslands in Shiroi City, Chiba Prefecture, Japan. Methods The 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. Results Habitat 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. Conclusions The 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.

Introduction: Citizen science has contributed substantially to the quantity of biodiversity data collections and is used as an essential monitoring scheme for global conservation studies. However, there remain large gaps in the geographic and taxonomic coverage of data collections, and different levels of interest in participation and uneven distribution of participants can result in biased data collection in citizen science programs. These issues must be addressed for more efficient use of citizen science-based biodiversity data. We compared web search volumes with citizen-collected occurrence data of Japanese Red List species. Outcomes: Uneven distribution of web search volumes with different taxa was correlated with the amount of data collected by citizen-volunteered programs. Moreover, the relative web search volumes and amounts of citizen-collected data showed similar spatial patterns at the province level. Conclusion: Overall, our results indicate that web search volume can indirectly reflect potential citizen participation or interest in particular species. Web search behavior can help project coordinators estimate potential citizen engagement and refine efficient citizen participation programs for biodiversity conservation.

Understanding how landscape composition affects pollinator abundance is crucial for conserving the sustainability of the symbiotic relationship between plants and pollinators. However, field evidence on the effect of landscape composition and spatial scales on the abundance of each pollinator group is biased toward bee pollinators, and non-bee pollinators tend to be excluded. This study aims to evaluate the effect of landscape composition at various spatial scales on diverse taxonomic groups of pollinators, including non-bee pollinators. We selected 22 grasslands with varying landscape compositions in Shiroi City, Chiba Prefecture, Japan. We recorded the abundance of pollinators and floral resource availability at these sites. The effects of landscape composition within a 100-1000 m radius and the floral resource availability were analyzed using Bayesian generalized linear mixed models to determine whether these factors affected the abundance of each pollinator group. As a result, the difference in important factors among the pollinator groups was detected; Scoliidae, Lycaenidae, Stomorhina obsoleta, and Sphaerophoria were influenced by the landscape composition, whereas Bombus diversus and Hesperiidae were not. Scoliidae was affected by the proportion of agri-field and forest areas within a 500-1000 m radius. St. obsoleta and Sphaerophoria showed different response patterns to the proportion of urban land within a 100 m radius. B. diversus and Hesperiidae were influenced by floral resource availability. Our study suggests that considering the spatial scales of landscape composition on the target species is essential to plan effective conservation measures.

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