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BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access titles in the biological, ecological, and environmental sciences published by nonprofit societies, associations, museums, institutions, and presses.

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Nutrient relocation, hydrological functions, and soil chemistry in plantations as compared to natural forests in central Yunnan, China Abstract The relocation of nutrients among dominant plant species, along with hydrological functions and soil chemistry in five plant communities, including Eucalyptus plantation, Pinus plantation, shrubland, semi-natural, and natural secondary forests were investigated in central Yunnan, China. The nutrient P, N, and K accumulation in above-ground biomass of Eucalyptus smithii (stems, barks, branches, and leaves) were the highest, followed by Pinus yunnanensis of both the Pinus plantation and the semi-natural forest. The nutrient retranslocation efficiency (NRE) of E. smithii was the highest for nutrient P, N, and K with values of 56, 66, and 67%, respectively, among the dominant plant species of the five plant communities, while the NRE of P. yunnanensis in Pinus plantation had the second highest value of NRE for nutrient N. The nutrient content (available P, N, and soil organic matter) in the upper two soil layers under Eucalyptus and Pinus plantations was correspondingly found to be lower than that of the other forests. Moreover, under the Eucalyptus and Pinus plantations, surface runoff, soil erosion, and nutrient loss were more serious, and the water storage of litterfall and canopy interception were significantly lower than that in the other plant communities. Accordingly, we suggest that single-species plantations cannot present the same ecological benefits as natural forests, because of their simple, uniform structures, and the characteristics of the dominant plant species.

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Three soil bacterial strains were identified as Chryseobacterium sp. TFB on the basis of their 16S rRNA gene sequences. Conidia of Arthrobotrys oligospora produced a few mycelial traps (MT) and conidial traps (CT) when cultured with bacterial cells that they did not produce when cultured with a bacterial cell-free culture filtrate. However, co-culture of A. oligospora with bacterial cells and bacteria-free filtrate simultaneously induced MT and CT in large amounts. With the increased concentration of bacteria-free filtrate, the number of typical CT increased, but conidial germination was progressively inhibited. Scanning electron microscopy of A. oligospora co-cultured with bacteria revealed that bacterial attachment to hyphae was a prerequisite to trap formation and that bacteria-free filtrate facilitated bacterial attachments to hyphae. The results that the addition of nutrients in co-culture medium decreased the number of traps suggest that this type of trap formation may be favoured at a low nutrient status. Eight fungi tested were able to form MT and CT when co-cultured with bacterial cells and bacteria-free culture filtrate, but the abilities varied among species. This study provides novel evidence that under laboratory conditions, soil bacteria attaching to hyphae could induce traps in nematode-trapping fungi.

Human-induced changes in land use lead to major changes in plant community composition and structure which have strong effects on eco-hydrological processes and functions. We here tested the hypothesis that changes in traits of living plants have resulted in changes in structural attributes of the community that influenced eco-hydrological functions by altering eco-hydrological processes. This was done in the context of a subtropical secondary forest suc­cession following land abandonment in Central Yunnan (Southwest China). During the succession, species with high specific leaf area (SLA), high leaf nitrogen concentration (LNC), high specific root length (SRL), and low leaf dry matter content (LDMC) were progressively replaced by species with the opposite characteristics. The obtained results of correlation analyses were as follows: (1) Correlations were significant between community-aggregated SLA, LNC, and the leaf area index (LAI). Significant correlations were detected between LAI, canopy interception and stemflow, and surface runoff and soil erosion. (2) Significant correlations were also found between community-aggregated SLA, LNC, LDMC, and accumulated litter biomass. High accumulated litter biomass strongly increases the maximum water-retaining capac­ity of litter. However, significant correlations were not found between the maximum water-retaining capacity of litter and surface runoff and soil erosion. (3) Correlations were significant between community-aggregated SLA, LNC, and fine root biomass. Fine root biomass was not significantly related to the maximum water-retaining capacity of the soil, but was significantly related to surface runoff and soil erosion. These results suggest that canopy characteristics play a more important role in control of runoff and soil erosion at the studied site. It follows that plant functional traits are closely linked with canopy characteristics, which should be used as a standard for selecting species in restoration and revegetation for water and soil conservation