Aim Conservation strategies must anticipate how climate change may alter the geographic distributions of limited food resources for highly specialized species. Here, we use bamboo as a case study to investigate climate change-induced changes in species diversity and discuss how to protect the critical food species for giant pandas.Location Giant panda habitats.Methods Using a niche-based model and the most updated climate projections, we projected the current and future distribution of 16 bamboo species under no and universal dispersal assumptions. We then assessed the impact of climate change on bamboo forests and their alpha and beta diversities in the giant panda habitats and reserves.Results Under both dispersal assumptions and three RCPs, six bamboo species are projected to vanish from panda habitats as climate change progresses, resulting in a great loss of the current bamboo forests. Although about half of the bamboo species may potentially colonize new climatically suitable areas under universal dispersal, the other species would experience significant habitat loss. Consequently, climate change would reduce both the alpha and beta diversity of bamboo species in panda habitats. Meanwhile, the proportion of single-species bamboo forests would significantly increase. The decline in bamboo forests and diversity would be most drastic in Qinling, Daxiangling and Qionglaishan Mountains, whereas those in the north-west of Minshan Mountains and Liangshan Mountains may increase.Main conclusions Climate change-induced decline in bamboo habitats and species diversity would pose a severe challenge to the food availability of giant pandas. We posit that human-assisted adaptation and increasing bamboo species diversity are critical to ensuring food security of the giant panda in a changing climate. Our results indicate that conservation planning should not only incorporate species range shifts but also diversity patterns in communities under climate change.

a b s t r a c tThis study aims to investigate the level of soil microbial biomass (MB) and analyze the relationships between soil MB and edaphic, vegetational and climatic factors at high elevation sites (>3000 m). We collected soil samples from 0 to 10 cm soil depth in 259 plots at 55 sites across 6 biomes in Three-River Headwaters (TRH) region at 3280-5127 m elevation. Soil microbial biomass carbon and nitrogen (MBC and MBN) were measured with the chloroform fumigation-extraction method. Multivariate stepwise regression analyses were used to analyze the combined effects of edaphic, vegetational and climatic factors on soil MB. We found: (1) soil MBC and MBN had an average of 30.95 mmol C/kg dry soil and 5.84 mmol N/kg dry soil in TRH, respectively, and their values were found to be negatively correlated with elevation; (2) soil MB was found to be significantly different among different biomes, and this spatial variation could be explained by the levels of soil organic carbon and belowground plant biomass. Our results indicate that the MB at high elevation region might be very low, and the increasing trend of soil microbial biomass with elevation could reverse at higher elevations.

This study investigated the effect of Bacillus subtilis (B. subtilis) natto on meat quality and skatole in TOPIGS pigs. Sixty TOPIGS pigs were randomly assigned to 3 groups (including 5 pens per group, with 4 pigs in each pen) and fed with basic diet (control group), basic diet plus 0.1% B. subtilis natto (B group), and basic diet plus 0.1% B. subtilis natto plus 0.1% B. coagulans (BB group), respectively. All pigs were sacrificed at 100 kg. Growth performance, meat quality, serum parameters and oxidation status in the three groups were assessed and compared. Most parameters regarding growth performance and meat quality were not significantly different among the three groups. However, compared with the control group, meat pH24, fat and feces skatole and the content of Escherichia coli (E. Coli), Clostridium, NH3-N were significantly reduced in the B and BB groups, while serum total cholesterol, high density lipoprotein, the levels of liver P450, CYP2A6, and CYP2E1, total antioxidant capability (T-AOC) and glutathione peroxidase and Lactobacilli in feces were significantly increased in the B and BB groups. Further, the combined supplementation of B. subtilis natto and B. coagulans showed more significant effects on the parameters above compared with B. subtilis, and Clostridium, and NH3-N. Our results indicate that the supplementation of pig feed with B. subtilis natto significantly improves meat quality and flavor, while its combination with B. coagulans enhanced these effects.