Recovered grassland area rather than plantation forest could contribute more to protect epigeic spider diversity in northern China

Several studies have documented the semi-natural habitats and heterogeneous landscape patterns play a crucial role in maintaining spider diversity in agricultural landscapes. However, which types of semi-natural habitat contribute more to conserve spider diversity and functional traits, and how they respond to landscape patterns at different landscape scales are still poorly understood. Thereby, we sampled epigeic spider communities by pitfall traps within recovered grasslands, plantation forests and croplands around three villages with different altitudes in northern China and surveyed the surrounding landscape structures in both 2017 and 2018. The results confirmed the diverse distribution of spiders in different habitat types. There was a greater spider activity density in recovered grasslands than that of plantation forests or croplands significantly. Furthermore, both recovered grasslands and plantation forests contained more species richness than croplands. Moreover, the spider community in the recovered grasslands and cropland had more similar functional trait compositions (including hunting types, body size and ballooning ability) comparing to the plantation forests, which mainly due to the higher proportion of ambush hunters in recovered grassland and cropland. Secondly, the study also indicated that the proportion area of plantation forest negatively affected spider diversity at multi-scales. Meanwhile, recovered grassland with high landscape diversity would benefit spider diversity only on a small scale like a 100 m radius. The spider functional traits were insensitive to landscape patterns. Overall, the study implies that increasing recovered grassland rather than plantation forest could protect spider diversity in northern China. The findings presented in this paper added to our understanding of how landscapes and different semi-natural affect the diversity of spiders and their functional traits. Meanwhile, the research results represent a further step towards developing more suitable landscape patterns and choosing restoration semi-natural types for policymakers to enhance biodiversity in agricultural landscapes.