Herbaceous phytoliths from forest and grassland in Northeast China: Potential significance for determining past forest–grassland boundaries

Abstract Phytoliths are a useful tool for reconstructing paleovegetation and paleoenvironments and grass short cell phytoliths (GSCPs), in particular, can provide important paleoenvironmental information. Although herbaceous phytoliths from non-grass species in forests also provide important paleovegetation information, they have not been investigated in as much detail as GSCPs, especially in Northeast China. In this study, we examined herbaceous phytolith morphotypes and assemblages from both forested and grassland areas in NE China, comprising three vegetation types. The phytoliths in 60 herbaceous quadrats were divided into seven morphotype groups. Cross-shaped phytoliths, bilobate type-C with long shank and papillate echinate morphotypes were only observed in grassland (GRA); complex saddle and bilobate type-A were only observed in non-understory vegetation in forested areas (NON); and phytoliths with scrobiculate decoration, elongate curved, silicified stoma (F), silicified stoma (D), globular granulate and oblong ruminate were only observed in forest understory (UND). Papillate (39.7%) was the dominant phytolith type in UND assemblages, and bilobate was dominant in NON (27.2%) and GRA (55.0%). According to the results of Discriminant Analysis (DA) and Detrended Correspondence Analysis (DCA), there was no similarity between UND and GRA, while NON had similarities with both UND and GRA. We conclude that herbaceous phytolith morphotypes and assemblages from forest and grassland in NE China are substantially different, which potentially enables their use for paleovegetation reconstruction in the region. Overall, our findings provide a new approach for determining past forest–grassland boundaries in NE China.