Wyniki wyszukiwania - Biblioteka Nauki

1

100%

Lu T. , Ma K. , Zhang Y. , Ni H. , Fu B.

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tom Vol. 57, nr 4

647-657

EN

Disturbance is considered to be one of the main factors influencing variations in species diversity. While many experimental and observational studies provide a good understanding of how disturbance maintains the [alfa]-diversity, we know little about how disturbance influences [beta]-diversity, and the effects of disturbance intensity on spatial species turnover are lacking. The aim of this paper is to evaluate the effects of disturbance on patterns of species similarity in wetland communities, and to identify how disturbance intensity affects the species similarity - distance relationship. In our study, four isolated wetland remnants under different agricultural drainage ditch densities were surveyed in Sanjiang Plain, Northeast China. Wetland disturbance was assessed by agricultural ditch densities, and species similarity was quantified by the Jaccard index. A simple measure of environmental distance was obtained by using water level and five soil variables, and a corresponding measure of geographical distance was made between pairs of plots from each site. Based on these data, we estimated rates of distance decay through regression of log-transformed compositional similarity against both environmental and geographical distance for pair-wise comparisons of wetland plots from each site. One key finding of our research is that disturbance intensity does influence the species similarity - distance relationship. At each site, species similarity decreased significantly with distance, and both effects of geographical and environmental distance were statistically significant. The results indicate that with disturbance intensity increasing, the distance decay rate decreases.

2

Species similarity - distance relationship in wetlands: effect of disturbance intensity

100%

Lu T. , Ma K. , Zhang Y. , Ni H. , Fu B.

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nr 4

647-657

EN

Disturbance is considered to be one of the main factors influencing variations in species diversity. While many experimental and observational studies provide a good understanding of how disturbance maintains the α-diversity, we know little about how disturbance influences β-diversity, and the effects of disturbance intensity on spatial species turnover are lacking. The aim of this paper is to evaluate the effects of disturbance on patterns of species similarity in wetland communities, and to identify how disturbance intensity affects the species similarity - distance relationship. In our study, four isolated wetland remnants under different agricultural drainage ditch densities were surveyed in Sanjiang Plain, Northeast China. Wetland disturbance was assessed by agricultural ditch densities, and species similarity was quantified by the Jaccard index. A simple measure of environmental distance was obtained by using water level and five soil variables, and a corresponding measure of geographical distance was made between pairs of plots from each site. Based on these data, we estimated rates of distance decay through regression of log-transformed compositional similarity against both environmental and geographical distance for pair-wise comparisons of wetland plots from each site. One key finding of our research is that disturbance intensity does influence the species similarity - distance relationship. At each site, species similarity decreased significantly with distance, and both effects of geographical and environmental distance were statistically significant. The results indicate that with disturbance intensity increasing, the distance decay rate decreases.

3

Effects of CO2 fumigation and nitrogen addition on soil respiration in a wetland ecosystem: experimental approach with top open chambers

86%

Wang J. , Fu X. , Wang J. , Zhong H. , Zhang R. , Ni H.

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nr 2

EN

Soil respiration plays a crucial role in global carbon cycling of terrestrial ecosystems. Changes in atmospheric CO₂ and nitrogen (N) addition across the globe are likely to affect soil respiration. However, the effects of elevated CO₂, and N addition on soil respiration are not fully understood especially in wetland ecosystems. To evaluate the effects of atmospheric CO₂ and N availability on soil respiration, a paired, nested manipulative in situ experiment was performed, using CO₂ fumigation within Open-Top Chambers as the primary factor, and N (as NH₄NO₃) as the secondary factor in a temperate wetland in northeastern China in 2010 and 2011. CO₂ fumigation significantly enhanced soil respiration, according to repeated-measures ANOVA, and the stimulatory effect of CO₂ fumigation on soil respiration was sustained during the whole experimental period regardless of N addition. However, the positive soil respiration effect of N addition alone weakened over time. Moreover, there was a significant interaction between CO₂ fumigation and N addition. Soil temperature explained 50–66% of the variation in soil respiration. Moreover, soil respiration was positively correlated with the root N content and litter decomposition rate. The results suggested that elevated CO₂ concentrations will accelerate soil respiration and ecosystem carbon cycling, thus, limiting soil carbon sequestration, especially when coupled with increasing N deposition.

4

Transcriptional analyses of endometrial caruncles in sheep with in vivo / in vitro produced embryos during the peri-implantation period

86%

Xing K. , Qi X. , Ni H. , Wang X. , Guo Y. , Sheng X.

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nr 4

5

An integrated analysis of testis miRNA and mRNA transcriptome reveals important functional miRNA-targets in reproduction traits of roosters

72%

Xing K. , Gao M. , Li X. , Feng Y. , Ge Y. , Qi X. , Wang X. , Ni H. , Guo Y. , Sheng X.

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tom 20

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nr 3