PDF(Pubmed)
Abstract：
Climate change will likely increase habitat loss of endemic tree species and drives forest conversion in mountainous forests. Elevation gradients provide the opportunity to predict possible consequences of such changes. While species compositions of various taxa have been investigated along elevation gradients, data on trophic changes in soil-dwelling organisms are scarce. Here, we investigated trophic changes of the Collembola communities along the northern slope of Changbai Mountain, China. We sampled Collembola in primary forests at seven elevations (800-1700 m asl). We measured individual body lengths and bulk stable isotopes on species level. We further categorized Collembola species into life forms. The community-weighted means of Δ15N and Δ13C values as well as minimum Δ15N values and isotopic uniqueness of Collembola communities increased with increasing elevation, while the range of Δ15N values decreased. Maximum and minimum of Δ13C values differed between elevations but showed no linear trend. Further, Δ15N values of Collembola species occurring across all elevations increased with elevation. Changes in Δ15N values with elevation were most pronounced in hemiedaphic species, while Δ13C values increased strongest with elevation in euedaphic species. Δ15N values increased with decreasing body size in hemiedaphic and euedaphic species. Overall, the results suggest that Collembola species functioning as primary decomposers at lower elevations shift towards functioning as secondary decomposers or even predators or scavengers at higher elevation forests. The results further indicate that access to alternative food resources depends on Collembola life form as well as body size and varies between ecosystems.
摘要：
气候变化可能会增加特有树种的栖息地丧失，并推动山区森林的森林转化。高程梯度提供了预测此类变化可能后果的机会。虽然已经沿着海拔梯度研究了各种分类单元的物种组成，关于土壤生物营养变化的数据很少。这里,我们调查了长白山北坡Collembola群落的营养变化，中国。我们在七个海拔（800-1700masl）的原始森林中采样了Collembola。我们在物种水平上测量了个体体长和总体稳定同位素。我们进一步将Collembola物种分类为生命形式。随着海拔的增加，Colembola群落的Δ15N和Δ13C值以及最小Δ15N值和同位素唯一性的群落加权均值增加，而Δ15N值的范围减小。Δ13C值的最大值和最小值在海拔之间有所不同，但没有线性趋势。Further,在所有海拔高度上出现的Collembola物种的Δ15N值随海拔高度的增加而增加。Δ15N值随海拔的变化在半叶物种中最为明显，而Δ13C值随着Euedaphic物种的升高而增加最强。Δ15N值随着半叶和松叶物种的体型减小而增加。总的来说,结果表明，在较低海拔地区充当初级分解者的Collembola物种向在较高海拔森林中充当次级分解者，甚至是捕食者或清道夫的转变。结果进一步表明，获得替代食物资源取决于Collembola的生命形式以及体型，并且在生态系统之间有所不同。
