Biodiversity and soil pH regulate the recovery of ecosystem multifunctionality during secondary succession of abandoned croplands in northern China.

The 'Grain-for-Green' program in China provides a valuable opportunity to investigate whether spontaneous restoration can reverse the deterioration of grassland ecosystem functions. Previous studies have focused on individual ecosystem functions, but the response of and mechanisms driving variation in ecosystem multifunctionality (EMF) during restoration are poorly understood. Here, we quantified EMF using productivity, nutrient cycling, and water regulation functions along abandoned croplands in a recovery chronosequence (5, 15 and 20 years) and in natural grasslands in the desert steppe and typical steppe. We also analyzed the effects of plant and microbial diversity and an abiotic factor (soil pH) on EMF. Our results showed that EMF increased gradually concomitant with recovery time, shifting toward EMF values comparable to those in natural grasslands in both desert and typical steppe. Similar results were found for the productivity function, the water regulation function, and soil organic carbon. However, even after 20 years of restoration, EMF did not reach the levels observed in natural grasslands. Structural equation modeling showed that the driving mechanisms of EMF differed between the two steppe types. Specifically, in the desert steppe, plant diversity, especially the diversity of perennial graminoids and perennial herbs, had a positive effect on EMF, but in the typical steppe, soil bacterial diversity had a negative effect, while soil pH had a positive effect on EMF. Our results demonstrated that spontaneous grassland restoration effectively enhanced EMF, and emphasized the importance of biodiversity and soil pH in regulating EMF during secondary succession. This work provides important insights for grassland ecosystem management in arid and semi-arid regions.

Spontaneous grassland recovery on abandoned croplands in northern China: Different vegetation patterns in desert and typical steppe.

Passive restoration (without any intervention) has been proposed as an effective strategy for grassland restoration in abandoned croplands. However, whether the vegetation in abandoned croplands can change towards the desired state and the time needed to reach a relative stable state are context-dependent. We investigated three abandoned croplands with different recovery times (5, 15 and 20 years) and one natural grassland in each of two different types of steppe (desert steppe and typical steppe) in the agro-pastoral ecotone of northern China to assess the restoration potential of grassland on abandoned croplands. Above- and below-ground biomass as well as species biodiversity increased gradually with increasing recovery time. After 20 years of restoration there was no significant difference between abandoned cropland and natural steppe in the typical steppe site, but above- and below-ground biomass and species biodiversity were still lower in abandoned cropland in the desert steppe site. At the beginning of restoration, the communities were dominated mainly by annual species, especially in the desert steppe. As recovery time increased, the biomass and richness of perennial graminoids and forbs increased significantly and replaced annual species as the dominant species. In both desert steppe and typical steppes, species similarity between restored and natural steppe increased over time, suggesting that previously cultivated grassland recovered towards the desired state. Our results indicate that 20 years was sufficient time for the restoration of croplands in the typical steppe, but more time may be needed in the desert steppe.

[Responses of the spatial distribution of Stipa breviflora to stocking rate at different scales.] / ä¸åŒå°ºåº¦ä¸‹è’æ¼ è‰åŽŸå»ºç¾¤ç§çŸ­èŠ±é’ˆèŒ çš„ç©ºé—´åˆ†å¸ƒå¯¹è½½ç•œçŽ‡çš„å“åº”.

We conducted an experiment to test the characteristics and differences of the spatial distribution of constructive species Stipa breviflora at different scales under different stocking rates in the S. breviflora desert steppe in Siziwang Banner, Inner Mongolia. The spatial distribution of S. breviflora under four treatments (control, light grazing, moderate grazing, and heavy grazing) at different scales (small scale as 1 m×1 m and mesoscale as 5 m×10 m) were analyzed. The results showed that the population density of S. breviflora at mesoscale in the control and light grazing was significantly lower than that at the small scale. Grazing significantly increased the population density of S. breviflora in the meso- and small scales. At the small scale, the population distribution of S. breviflora in the control, light grazing, moderate grazing, and heavy grazing treatments conformed to linear, exponential, exponential and exponential models, respectively, and Gaussian, exponential, Gaussian and exponential models at mesoscale fitted by semi-variance function. The spatial distribution pattern at small scales in the control was simple and better but was more complex and poorer under the heavy grazing. At the mesoscale, it was simple and better under the heavy grazing but complex and poor under the moderate grazing. The spatial heterogeneity of S. breviflora population reduced and were more uniform under the moderate and heavy grazing at meso- and small scales. In addition, the trend of population distribution in the enclosure, moderate and heavy grazing were generally the same, while light grazing showed inconsistent trend at different scales.

[Effects of mowing height on community structure and stability in Stipa grandis steppe]. / åˆˆå‰²ç•™èŒ¬é«˜åº¦å¯¹å¤§é’ˆèŒ è‰åŽŸç¾¤è½ç»“æž„åŠç¨³å®šæ€§çš„å½±å“.

We examined the effects of mowing height on community structure and stability in August from 2014 to 2018 in a Stipa grandis steppe of Xilingol, Inner Mongolia, China. Three mowing height treatments (2, 5 and 8 cm) were manipulated, with enclosure as the control. Results showed that 27 species from 23 genera of 15 families were recorded in the community. The community was dominated by S. grandis, Anemarrhena asphodeloides, Leymus chinensis and Cleistogenes squarrosa. The cumulative relative importance value of those four species was 76.1%. Of all species, there were 15 perennial forbs, 5 annuals biennials, 3 perennial bunch grasses, 3 shrubs semi-shrubs, and 1 perennial rhizome grasses. S. grandis was in the upper layer of the community, L. chinensis and A. asphodeloides were in the middle layer, C. squarrosa, Chenopodium aristatum and Salsola collina were at the bottom layer. Mowing decreased the relative importance value (RIV) of S. grandis and perennial bunch grasses, but increased that of C. squarrosa, C. aristatum, S. collina and annuals biennials. The RIV of L. chinensis was decreased in the 2 cm treatment but increased in the 5 cm and 8 cm treatments. The RIV of A. asphodeloides was increased in the 5 cm treatment but decreased in both the 2 cm and 8 cm treatments. The RIV of perennial forbs was decreased in the 8 cm treatment but increased in both the 2 cm and 5 cm treatments. Species and functional groups diversity showed significant interannual variation. Generally, species richness and diversity were little affected by mowing, while functional groups diversity was significantly impacted, indicating that compensation between different functional groups would stabilize the community under mowing. Mowing increased community stability. Community stability was higher in the 5 cm and 8 cm treatments, with the variability being larger in the 5 cm than in the 8 cm treatment. Therefore, the 8 cm treatment was beneficial for the stability and sustainable utilization of grassland community.

[Analysis of imported falciparum malaria cases of Nantong City from 2001 to 2010].

OBJECTIVE: To analyze the characteristics of imported falciparum malaria cases of Nantong City in the recent ten years so as to provide the evidence for improving prevention and control of malaria in the future. METHODS: The data about imported falciparum malaria cases of Nantong City from 2001 to 2010 were collected and analyzed for the characteristics and distribution of the patients by the retrospective method. RESULTS; There were 79 imported falciparum malaria cases in the last 10 years. Totally 96.2% of patients were infected in Africa. Most of them were young people and worked for the construction services. Seasonal distribution difference was not obvious. CONCLUSIONS; The imported falciparum malaria epidemic is rising in Nantong City. Therefore, we should strengthen the anti-malaria health education to increase the self-protection of labors, and strengthen the training of medical stuff and also strengthen the monitoring of malaria epidemic.

[High-risk behaviors related to AIDS/STDs infections among fishermen in Lü-si harbor, Jiangsu province].

OBJECTIVE: To investigate the high-risk behaviors related to acquired immune deficiency syndrome/sexually transmitted disease (AIDS/STDs) infection among fishermen in Lü-si harbor, Jiangsu province. METHODS: A cross-sectional study was designed to investigate the research participants' demographic characteristics, high-risk behaviors that related to AIDS/STDs. Logistic regression was performed to measure the associations between potential risk factors and reported potential high-risk sexual behavior. RESULTS: 817 fishermen participated in the study and casual or commercial sex activities appeared to be the main high-risk behavior for AIDS/STDs infection in the target population. The rates of casual and commercial sex reported were 18.1% and 28.9% among fishermen. Risk factors associated with AIDS/STDs related high-risk behaviors among fishermen were high mobility (OR = 1.516, P = 0.038), higher lifetime sex frequency (OR = 1.422, P = 0.002) and unmarried status (OR = 7.527, P = 0.014). Protective factors against high-risk behaviors were low intake of alcohol (OR = 0.803, P = 0.053), negative STD history (OR = 0.268, P = 0.001), age of initial sexual intercourse at or older than 22 years (OR = 0.440, P = 0.000) of age, as well as negative attitude toward multiple sexual partners (OR = 0.662, P = 0.023) and legitimation for commercial sex (OR = 0.612, P = 0.007). CONCLUSION: There were risk behaviors of AIDS/STDs in those infected fishmen. Casual and commercial sex were common high-risk behaviors.

[A related heredity epidemiological research on allergic rhinitis and asthma in Nantong region].

OBJECTIVE: To discuss the related impact of genetic factors in the incidence of bronchial asthma (BA) and allergic rhinitis (AR) in Nantong region, China. METHODS: By random sampling method, investigation and research on the incidence of genetic epidemiology were carried out in the population of 95 300 on AR and BA. RESULTS: The rate of patients with allergic rhinitis with asthma was 25.92% (296/1142), the rate of asthma patients with allergic rhinitis was 40.49% (296/731). The prevalences of AR complicated with BA were 8.19% (280/3418), 3.08% (154/5002) and 3.16% (85/2687) in the first-, second-and third-degree relatives of the probands respectively, while the prevalences of BA complicated with AR were 15.81% (466/2947), 4.61% (229/4967) and 2.51% (134/5345) in the first-, second- and third-degree relatives of the probands respectively, higher than those in the controls (P < 0.05). The weighted mean heritability of AR in BA patients was 94.2% ± 1.9%, while the weighted mean heritability of BA in AR patients was 81.8% ± 2.1%, more than 60%, suggesting that both AR and BA were relevant with genetics. CONCLUSIONS: The incidence of BA and AR has obvious relevance, supporting the theory that the two diseases are an united airway disease and relevant with polygene heredity.

[Genetic epidemiological study on allergic rhinitis in Nantong region of Jiangsu Province].

OBJECTIVE: To explore the effects of genetic factors on the occurrence of allergic rhinitis (AR). METHODS: The morbidity rate of AR was surveyed by multistage sampling among 95 300 individuals (23,825 families) in Natong region, Jiangsu province. And a genetic epidemiologic investigation on AR was carried out to estimate the segregation ratio and heritability (h2) of AR by the methods of Li-Mantel-Gart and Falconer respectively. RESULTS: The morbidity rate of AR in Natong region was 1.20% (Male 1.21%, Female 1.18%, no statistical significance between them); By the data of the AR ancestry, the segregation ratio of AR in Nantong region was 0.078, significantly less than 0.25, and the genetic model belonged to polygenetics. The 1st, the 2nd, and the 3rd generation h2 of AR were (82.6 +/- 2.19)%, (80.8 +/- 2.93)%, (78.4 +/- 7.04)%. The h2 of AR was (81.86 +/- 1.70)%. In the ancestry of AR, the morbidity rate of the 1st generation with AR was 12.11%; the 2nd generation with AR was 5.12%; the 3rd generation with AR was 2.75%; and the morbidity rate of AR in general population was 1.20%. CONCLUSIONS: The heredity in family with AR is obvious. Several genes plus the environmental factors may cause AR, which accords with the characteristics of the polygene heredity disease.

Detection of IgG-bound lipoprotein(a) immune complexes in patients with coronary heart disease.

BACKGROUND: LDL-immune complexes (IC) have a powerful pathogenic role for inducing foam cell formation in vitro more efficiently than any other known mechanism. Studies have also shown that plasma LDL-IC concentration is a powerful marker for the development of atherosclerosis. The structure, fatty acid composition and antioxidant concentrations of Lp(a) and LDL are quite similar. The same oxidation pattern has also been described for both lipoproteins. Modified forms of Lp(a), some resembling oxidized Lp(a), have been identified in human atheromatous lesions. The existence of autoantibodies against MDA-Lp(a) in vivo is also presented. Therefore, we suppose that Lp(a) might trigger an immune response leading to the production of autoantibodies and subsequently to the formation of immune complexes. This study examined the existence of IgG-bound Lp(a)-IC and investigated its value as a risk factor for the development of atherosclerosis. METHODS: We developed two "sandwich" ELISAs for measuring plasma Lp(a)-IC and LDL-IC concentrations, using anti-human IgG(Fab) as the capture antibody, and quantitating with monoclonal anti-apo(a) or anti-apoB enzyme conjugate. Their concentrations were studied in 160 patients with coronary heart disease (CHD) and 290 control subjects. RESULTS: Plasma TC, LDL-C, TG and apoB concentrations in CHD patients were all significantly increased, whereas HDL-C and apoAI concentrations were decreased. The Lp(a) concentrations in the patients with CHD were also significantly different from those of control (262.4+/-220.0 vs. 211.3+/-199.4 mg/l, P<0.005). Plasma Lp(a)-IC (2.24+/-1.71 vs. 1.62+/-1.50 AU, P<0.0001) and LDL-IC (2.77+/-1.29 vs. 1.40+/-0.92 AU, P<0.0001) concentrations in patients with CHD were both significantly higher than those of control. The relationships between Lp(a)-IC, LDL-IC concentrations and other lipid traits in all the studied subjects (n=450) were carried out. LDL-IC concentrations were positively correlated with LDL-C, apoB, TC, TG and Lp(a) concentrations, while negatively correlated with HDL-C and apoAI concentrations, respectively. Similarly, Lp(a)-IC concentrations were positively correlated with Lp(a), LDL-C, apoB and TC concentrations, while negatively correlated with HDL-C and apoAI concentrations, respectively. Furthermore, a significantly positive relation between LDL-IC and Lp(a)-IC concentrations was also found (r=0.313, P<0.0001). CONCLUSIONS: We report the existence of Lp(a)-IC in both the plasma of patients with CHD and control subjects. Lp(a)-IC concentration increases in the CHD patients.