The effects of functional differences in cultivar of Cryptomeria japonica on nutrient dynamics and soil invertebrates in a common garden

Abstract

Recently, some studies have established the ecological effects of intraspecific variation in phytochemical traits on soil ecosystems. Because plantations comprise a major proportion of forest area in some regions, intraspecific functional variation in plantation tree species is of great importance to forest ecosystems. Intraspecific variation in plantation tree species can result from natural geographical and cultivated variation. A previous study estimated the effects of geographical variation of Cryptomeria japonica, the most dominant plantation tree in Japan. The results showed that the significant consequences for ecosystem processes, such as calcium (Ca) dynamics and community composition of soil invertebrates, vary among the geographical variation of C. japonica. However, no studies have shown the effect of cultivar variation of tree species on the soil invertebrate community through alteration of the availability of nutrients. In this study, we used a common garden where four cultivars of C. japonica (Kumotoshi, Aya, Obi, and Satsumameasa) were planted in separate plots. In these plots, we measured the concentration of nutrients in leaves, litter and roots, strontium isotope ratio ( 87 Sr/ 86 Sr) of leaves. Root activities, exchangeable nutrients in soil, and soil parameters such as soil pH and abundance and composition of soil invertebrates. Our results show that cultivating different varieties of C. japonica may alter the accumulation of Ca in soil and soil pH. Furthermore, the effects of the cultivated varieties of C. japonica shape the abundance and composition of soil invertebrates by altering the soil properties, such as Ca concentration and pH in the soil.

Preface: Functional biogeography in Japanese cedar

“…It is thought to have played an important role in the ecosystem as a foundation species due to its high biomass (Ellison et al, 2005). It is not only makes a significant contribution to carbon sequestration by raising forest biomass (Aiba et al, 2007), but it also prevents soil acidification under certain conditions (Baba et al, 2004; Tanikawa et al, 2014), thereby contributing to the rich soil fauna (Ohta et al, 2019; Ohta & Hiura, 2023). In particular, among the functional traits that the cedar possesses, the calcium abundance in trunk and leaves may be related to these ecosystem functions.…”

“…In the process of afforestation, attention has been focused on high growth rates and good wood quality (Sakaguchi, 1983), and little attention has been paid to the various other functional differentiation unique to each region. The effects of the cedar species on the nutrient cycling and soil faunal community differ among artificial cultivars (Ohta & Hiura, 2023). The effects of artificially created cultivars on ecosystem functions and services should also be noted in the future, as their cascading effects differ from those of naturally selected natural geographic variations.…”

“…Common garden experiments are useful to clarify whether such geographic functional differentiation is a genetic trait. We are revealing geographic differentiation of some functional traits from common garden experiments in the Japanese cedar (Azuma et al, 2023;Hiura et al, 2021;Ohta et al, 2019;Ohta & Hiura, 2023;Saito et al, 2023).…”