Abstract:

Aims: Changes in forest types resulting from artificial plantations significantly influence the structure and function of soil animal communities. Collembola constitute a crucial decomposer group within soil ecosystems. Given the substantial variation in body size among Collembola species and the non-linear relationships between body size, body mass, and metabolic rate within Collembola, the main aim of the present study is to evaluate the (dis)similarities in the effects of forest type changes and the physicochemical properties of litterfall on the ‘stock’ functions (density and biomass) and ‘flow’ functions (metabolic rate) of soil Collembola. 

Methods: In this study, five replicate plots were established in each of three forest types—natural secondary Quercus liaotungensis forests, 60-year-old artificially planted Larix principis rupprechtii plantations, and Pinus tabulaeformis plantations. Soil Collembola samples were extracted and identified to morphospecies. Mean body length was measured for each morphospecies, and was then converted to body mass and metabolic rates. The effects of forest type and litter biomass and nitrogen and phosphorus concentrations on the total density, biomass, and metabolic rate, as well as the community weighted means (CWMs) of body length, body mass, and metabolic rate of Collembola were evaluated. 

Results: The results showed that (1) forest type did not significantly affect the total density, total biomass, or total metabolic rate of Collembola communities. However, the density structure, biomass structure, and metabolic structure of Collembola communities in pine plantations differed significantly from those in larch and oak forests; (2) nitrogen and phosphorus concentrations of leaf litters, rather than litter biomass, significantly influenced (positively correlated with) the density, biomass, and metabolic rate of Collembola class and three orders of Collembola; (3) forest type did not significantly affect the CWMs of body length, body mass, or mean metabolic rate, however, it significantly influenced the CWMs of those functions of Entomobryomorpha and Symphypleona. Furthermore, litter biomass and nitrogen/phosphorus concentrations were significantly correlated with the CWMs of body length, body mass, and metabolic rates of certain Collembola orders. 

Conclusion: The study results indicate that sixty-year-old larch plantations exhibited comparable functions of Collembola, such as the structures of density, biomass, and metabolic rates, with natural oak forests on the Dongling Mountain; while pine plantations significantly altered these functions of Collembola, primarily attributable to the low-quality litter (characterized by reduced nitrogen and phosphorus concentrations). The extent to which forest type and leaf litter properties influence density, biomass, and metabolic rate, as well as the CWMs of body length, body mass, and metabolic rates of Collembola vary with Collembola orders. Furthermore, this study demonstrates that forest type and litter properties exert similar effects on the metabolic rate and biomass across three Collembola orders, whereas their impacts on the density of Collembola shows considerable difference. By analyzing differences in the effects of environmental variables on both ‘stock’ functions (e.g., density and biomass) and ‘flow’ functions (e.g., metabolic rate) at both the class and order levels of Collembola, this study provides a novel perspective for systematically investigating how environmental changes influence the ecological functions of soil animal communities.

Key words: soil animal, energy metabolism, body size, plantation, natural forest