Calcium concentration in leaf litter affects the abundance and survival of crustaceans in streams draining warm–temperate forests

Abstract

Summary Stream ecosystems receive large quantities of nutrients from terrestrial ecosystems that influence community dynamics. However, few studies have investigated the effects of subsidiary calcium, an essential element of animals, on stream ecosystems. We focused on differences in calcium concentrations of leaf litter between tree species. In particular, litter of Japanese cedar (Cryptomeria japonica) has a higher concentration of calcium than other taxa, and the tree is planted in many parts of Japan. Therefore, we predicted that a C. japonica plantation would affect the supply of subsidiary calcium to stream ecosystems. We compared calcium concentration of leaf litters, soils, stream water and stream benthic invertebrates sampled at nine sites in catchments composed of cedar plantations, evergreen broad‐leaved forest and clear‐cut areas. In addition, we placed 10 Gammarus nipponensis in each of 10 nylon cages in the nine streams and after one month surveyed the number of surviving individuals. Calcium concentration in stream water and soil, and the density and survival of the dominant crustacean (Gammarus nipponensis) were significantly higher at sites dominated by C. japonica compared with other forest types. Furthermore, invertebrate community composition was correlated with total calcium and nitrate in stream water, indicating that terrestrial vegetation can affect stream invertebrate communities, particularly crustaceans.