Elevational patterns of functional diversity and trait of Delphinium (Ranunculaceae) in Hengduan Mountains, China.

Elevational patterns of trait occurrence and functional diversity provide an important perspective for understanding biodiversity. However, previous studies have mostly examined functional diversity at the community scale. Here, we examined large-scale patterns of trait occurrence and functional diversity in Delphinium along an elevational gradient from 1000 to 5700 m in the Hengduan Mountains, SW China. Elevational distribution and trait data of 102 Delphinium species were compiled to evaluate the patterns of interspecific traits, species richness, and functional diversity. We found that the distribution of species richness showed a unimodal curve that peaked between 3500 and 4000 m; functional diversity and traits showed different patterns along an elevational gradient. The functional diversity increased at a lower rate along an elevation gradient, whereas species richness continued to increase. Species with large ranges and non-endemic species were most affected by geometric constraints. Richness of species endemic to the Hengduan Mountains peaked at higher elevations, likely due to increased speciation and restricted dispersion under alpine conditions. We conclude that the middle elevation region is not only the functionally richest but also the most functionally stable region for Delphinium, which could be insurance against environmental change. Extreme conditions and strong environmental filters in an alpine environment may cause the convergence of species traits, which could relate to reducing nutrient trait investment and increasing reproductive trait investment. We conclude that large-scale studies are consistent with previous studies at the community scale. This may indicate that the relationship between functional diversity and species richness across different scales is the same.

[Distribution of Micro-plastics in the Soil Covered by Different Vegetation in Yellow River Delta Wetland].

Micro-plastics (MPs) pollution has been a hotspot in soil environment. To explore the correlation of the vegetation cover and the distribution of MPs in Yellow River Delta wetland, the characters of MPs in the soil sampled at 16 sites where reed (Phragmites communis, a low-salt dominant species) and Suaeda salsa (a high-salt dominant species) covered were investigated. The abundance of MPs here ranged to 80-4640 n·kg-1, and the particle size ranged to 13 µm-5 mm. The main components of MPs with large size were polyethylene (PE), polyethylene terephthalate (PET) and polystyrene (PS), and the content of PET ranged to 0.22-1.16 µg·kg-1. The barrier effect of reed on MPs was higher than that of Suaeda salsa. The average abundance of MPs and PET contents at the sites where reed covered were 1423 n·kg-1 and 0.62 µg·kg-1, and they mainly consisted of small particles with a size less than 50 µm. The average abundance of MPs and PET contents at the site Suaeda salsa covered were 584 n·kg-1 and 0.33 µg·kg-1, and they mainly consisted of fragments and fibers with a size ranged to 100-1000 µm. The abundance of MPs in the soil was significantly correlated with the growth statues of the vegetations (P=0.001). Therefore, the distribution of MPs in the soil in the same area covered by different vegetation might be spatial different.

[Carbon storage of Pinus thunbergii and Robinia pseudoacacia plantations on Nanchangshan Island, Changdao County of Shandong Province, China].

Using indigenous tree species to transform large area pure plantations has been an effective close-to-nature forest management mode in China islands. By using the biomass allometric equation and combined with the investigation data from sampling plots, the carbon storage of the dominant species Pinus thunbergii and Robinia pseudoacacia in the plantations on the Nanchangshan Island of Miaodao Archipelago in Changdao County of Shandong Province was estimated. The average carbon storage in the arbor layer of P. thunbergii and R. pseudoacacia plantations was 56.81 and 37.26 t x hm(-2), respectively, being higher than the average carbon stock (27.62 t x hm(-2)) of tree plantations in Shandong Province. Slope aspect and stand density were the important environmental and biological factors affecting the tree's carbon stock in the Island, respectively. There was no significant correlation between the average cumulative rate of biomass in the arbor layer of P. thunbergi plantation and the stand age. The P. thunbergii with good carbon sequestration function could be an ideal tree species on Nanchangshan Island.

[Phytoplankton assemblages and their relation to environmental factors by multivariate statistic analysis in Bohai Bay].

A detailed field survey of hydrological, chemical and biological resources was conducted in the Bohai Bay in spring and summer 2007. The distributions of phytoplankton and their relations to environmental factors were investigated with multivariate analysis techniques. Totally 17 and 23 taxa were identified in spring and summer, respectively. The abundance of phytoplankton in spring was 115 x 10(4) cells x m(-3), which was significantly higher than that in summer (3.1 x 10(4) cells x m(-3)). Characteristics of phytoplankton assemblages in the two seasons were identified using principal component analysis (PCA), while redundancy analysis (RDA) was used to examine the environmental variables that may explain the patterns of variation of the phytoplankton community. Based on PCA results, in the spring, the phytoplankton was mainly distributed in the center and northern water zone, where the nitrate nitrogen concentration was higher. However, in summer, phytoplankton was found distributed in all zones of Bohai Bay, while the dominant species was mainly distributed in the estuary. RDA indicated that the key environmental factors that influenced phytoplankton assemblages in the spring were nitrate nitrogen (NO3(-) -N), nitrite nitrogen (NO2(-) -N) and soluble reactive phosphorus (SRP), while ammonium nitrogen (NH4(+) -N) and water temperature (WT) played key roles in summer.