草原生态系统狭翅雏蝗种群的能量动态

ENERGY DYNAMICS OF THE GRASSHOPPER(CHORTHIPPUSDUBIUS ZUB) POPULATIONS IN THREE DIFFERENTPLANT COMMUNITIES IN INNER MONGOLIALGRASSLAND ECOSYSTEM

为揭示蝗虫在草原生态系统中的地位和作用,作者从一关键种着手,采用室内能量参数(取食量、排泄量、呼吸量、生产量)的测定结合野外自然种群数据的方法,讨论了3个植物群落(代表不同的退化程度)中狭翅雏蝗的能量动态。结果表明:(1)狭翅雏蝗种群的生产量(P)为1.1—2kJ/m^2,通过种群的能流(A)为3.4—6.6kJ/m^2,(2)其同化效率(A/C)为48％—58％,生态效率(P/C)为14％—18％,生长效率(P/A)为30％—32％;(3)狭翅雏蝗总摄食量(C)为6.9—13.8kJ/m^2,占地上初级生产量的0.21％—1.03％;另有0.21％—1.93％的牧草因蝗虫取食而掉落;狭翅雏蝗对牧草的压力表现为在越退化的草场,其压力越大。

Chorthippus dubius (Zub.) is a dominant species of grassshopper in northwestern pasture of China. The present paper deals with the energy flow through the grasshopper populations in three different plant communities representing different degree of degradation in Inner Mongolian grassland. Results indicated that the amount of energy consumed and assimilated from the net production of aboveground vegetation was of the order of 0.21%-1.03% consumed and 0.1%-0.59% assimilated. Additional 0.21%-1.93% of this production were out and dropped by the grasshopper populations. Approximately 0.03%-0.06% of the energy of net aboveground primary production were converted by the grasshopper populations into body and were available to higher trophic levlls.By comparison, the grasshopper population in the most degraded plant community had the strongest grazing pressure on the pasture, but the population in restorative plant community had the hightest net production. Similar efficiencies were found among the Chorthippus dubius populations in these three different communities, i. e., growlh efficiency (P/A), 30%-32%, ecological efficiency (-P/C), 14%-18%, and assimilation efficiency (A/C), 48%-58%.