The relative abundance of different components of the soil food web can vary tremendously in response to plant resource inputs. However, little is known about the mechanisms that plant resource regulates the energy fluxes and soil community composition. Here, we experimentally reduced litter and root inputs for two years in China at low-, mid-, and high-latitude forests to explore the effects of plant-derived resource inputs on the nematode energy flux and community composition. Litter reduction at high and mid latitudes and root removal at low latitudes reduced nematode richness but did not alter nematode abundance. Besides, litter reduction reduced energy fluxes of bacterialfeeding nematodes at mid latitudes and energy fluxes of plant-feeding, bacterial-feeding and omnivorous-predatory nematodes at low latitudes, thus reducing the energy fluxes of total nematodes in mid-and low-latitude forests. By contrast, root removal reduced energy fluxes and relative energy flux of plant-feeding nematodes in high-and low-latitude forests. In most cases, nematode diversity in different trophic groups increased with increasing energy flux to nematodes. Taken together, our results suggest that the effects of plant resource inputs on nematode energy flux are affected by climate and plant resource type, which improves our understanding of plant-soil interactions.

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Understanding the linkages between aboveground and belowground ecosystems is important for explaining the variation in soil organisms with plant communities on a spatiotemporal scale. Here, soil nematode communities were investigated across three successional stages (early, mid, and late) in two contrasting forests at low and high latitudes in China. We found that forest succession affected the relative abundance of some nematode trophic groups, whereas it did not alter the total nematode abundance in the two forests. Nonmetric multidimensional scaling analysis showed that nematode community composition changed significantly from the early and mid‐stages to the late stage. The mantel analysis showed that total soil P at low latitude and litter C:N ratio at high latitude were more closely related to the variation in nematode community during forest succession, respectively. Total nematode diversity increased marginally with forest succession at low latitude, but first increased and then decreased with forest succession at high latitude. Interestingly, total nematode diversity was related to plant‐feeding nematode diversity during forest succession in both the forests. In addition, structural equation models showed that the diversity of different nematode trophic groups was directly affected by forest succession and indirectly affected by the quantity of soil resources and the quality of soil and litter. More importantly, forest succession drives total nematode diversity by directly affecting plant‐feeding nematode diversity. Collectively, forest succession alters the diversity and increases the dissimilarity of soil nematode communities. However, changes in soil and litter properties during forest succession at different latitudes differentially influence nematode communities.

The ever-increasing atmospheric CO 2 concentration is a key driver of modern global warming. However, the low heat capacity of atmosphere and strong convection processes in the troposphere both limit heat retention. Given the higher heat capacity and CO 2 concentration in soil compared to the atmosphere, the direct contributions of soil to the greenhouse effect may be significant. By experimentally manipulating CO 2 concentrations both in the soil and the atmosphere, we demonstrated that the soil-retained heat and the slower soil heat transmission decrease the amount of heat energy leaking from the earth. Furthermore, the soil air temperature was affected by soil CO 2 concentration, with the highest value recorded at 7500 ppm CO 2. This study indicates that soil and soil CO 2 , together with atmospheric CO 2 , play a crucial role in the greenhouse effect. The spatial and temporal heterogeneity of soils and soil CO 2 should be further investigated, given their potentially significant influence on global climate change.