Abstract:The morphological variations of branches, leaves, flowers, fruits and seeds of Caragana microphylla and their correlations with environmental factors were analyzed based on five natural populations in the Xilingol steppe, Inner Mongolia, China. Nested variation analysis showed that there were significant differences in all of the 28 morphological characters within and among populations in 16 morphological characters, and the variations within populations were much greater than those among populations in most morphological characters. Cluster analysis showed that the five populations of C. microphylla could be divided into two groups in morphological characters, and there was significant positive correlation between the divergence of morphological characters matrix and geographical distance matrix. Principal component analysis showed that leaflet length, area of a compound leaf, fresh-mass of a compound leaf, and shoot fresh-mass were main morphological characters that varied among C. microphylla populations. Spearman correlation analysis showed that there were significant correlations between some morphological characters and soil factors. Soil N:P ratio, available N content, total N content, organic matter content and soil water content were main factors that were associated with morphological characters of C. microphylla.

Abstract:Land use change and land-cover impacts ecosystem services and functions. In this paper according to the study area’s land use characteristic and ecosystem type, the Land use category of the study area was divided into seven categories, including Forest, Grassland, Farmland, Water, Wetlands, Urban land and Barren land. The dynamic information of the forest Land use change during 10 years was calculated by the map algebra in ArcGIS 9.2. Both in 1992 and in 2002, Forest and Grassland were two largest Land use category in the study area. Forest took up 44.7% and 39.4% of the total area, and Grassland was 50.13% and 50.72% of the total area in 1992 and 2002. Finally, we valued change in ecosystem services delivered by each land use category using coefficients published by Costanza et al. [5]. Ecosystem services value of study area, the total ecosystem services value of 10.6 million hectares of this study area decreased by 11.74%. From the coefficient of sensitivity (CS) was less than unity in all case, it indicated that the total ecosystem services values was relatively inelastic and the results suggest that we have to pay attention more on land use change and finally, policy for driving forces of land use change were developed.

Abstract:In order to explore the ecological adaptation in leaf microstructures of Populus euphratica and Tamarix ramosissima in the lower reaches of Tarim River; we used scanning electron microscopy to observe epidermal, cuticular and cross-sectional structures of P. euphratica and T. ramosissima leaves. In addition, their cell submicroscopic structures were studied with transmission electron microscopy. The results revealed that through long-term adaptation to the same environmental conditions, micro-structural of the leaves for the two species exhibit high degree of homoplasy: there is cavity between cuticle and epidermal, and cuticle bulges outwards to form processes mammillaris and epidermal hairs; stomata concaves; fence and vascular tissues are developed; both alisade cells and thin walled cells have chloroplast; vacuoles occupies large volume of the cell space; etc. These features help plants resist drought stress. The salt glands and salt crystallization of T. ramosissima reveals the strong ability of salt stress resistance, but its drought-resistance capacity is weaker than P. euphratica. The specific components of the various shapes of crystal structures in their leaves call for further study.

Abstract:The characteristic of change in value of Tarim River ecosystem service function and its causes are discussed by combining the remote-sensing images with social statistical data related to the change in land utilization of Tarim River Main stream area during 1973–2005 and applying correlation analysis, regressional analysis and principal component analysis methods. The results show a right ascension state in the value of Tarim River ecosystem service function over the past 30 years. Of which, the Cropland ecosystem service function is of the largest increment in the economic value, which is far in excess of other ecosystem systems; the capacity of forest, grassland and wetland in service supply and value attribution show a downward tendency relatively; the area of Cropland and unused land ecosystems increase while that of forest, grassland and wetland ecosystems decrease, which indicates that the integral capacity and balance of the ecosystem in the region investigated has been affected severely and the ecosystem deteriorated; the economic activity of human is the key factor to regulate the change in economic value of Tarim River ecosystem service function and its trend in development.

Abstract:The growth situation of seedlings of treeline species can be used as an indicator for the upper or lower shift of treeline under global climate change, since any advance of a treeline would require seedling survival above the current treeline elevation. We investigated seedling and sapling density of two dominant conifers Abies georgei var. smithii and Sabina saltuaria at lower, middle and upper altitude of two contrasting slopes in Sergyemla Mountain, southeast Tibet. Seedling and sapling age structure of A. georgei var. smithii was analyzed further. Seedling density of both species, as well as sapling density of S. saltuaria, showed a declining trend as elevation increased. Sapling density of A. georgei var. smithii was somewhat higher at middle altitude than other positions. The frequency of old-aged A. georgei var. smithii seedlings/saplings (age >10 year) was the lowest at the highest altitude and tended to increase with the declining elevation. The results indicate that the higher density of seedling and sapling in high-altitude might be attributed to better soil moisture availability and solar insolation than in the mid- and low-altitudes during the growth season. Yet confined by other environmental factors, A. georgei var. smithii seedlings in high-altitude suffer from lower survival rate and lower possibility to grow tall compared with those in mid- and low-altitudes.

Abstract:Freshly-laid eggs of the Chinese three-keeled pond turtle (Chinemys reevesii) from captive cohorts in Hunan, Shanghai and Jiangxi were incubated at four constant temperatures of 24, 26, 28 and 30 °C to assess the effects of incubation temperature and cohort origin on incubation duration and hatchling phenotypes. Eggs from the three cohorts differed in size and shape. Egg mass and width were greatest in the Hunan cohort, smallest in the Jiangxi cohort, with the Shanghai cohort in between. Incubation duration decreased with increasing temperature and differed among the cohorts, with longer incubation duration for eggs from the Jiangxi cohort than those from the Hunan or Shanghai cohorts. Incubation temperatures significantly affected hatchling size and hatchlings from 30 °C were smaller than those from the lower temperatures in terms of carapace size and body mass. When incubated at a common temperature, hatchlings from the Hunan and Shanghai cohorts were larger than those from the Jiangxi cohort. The swimming capacity of hatchlings was affected by incubation temperature, but did not differ among the cohorts. The characteristics of eggs and hatchlings were similar among the Hunan and Shanghai cohorts, but they differed significantly from the Jiangxi cohort.

Abstract:Bird-aircraft collisions (birdstrikes) pose a major threat to aviation safety worldwide. The bird distribution at the airfield of Huanghua International Airport in Changsha, Hunan Province, China, was investigated between December of 2006 and December of 2008, to study birdstrike avoidance and aviation safety. A total of 60 bird species was found and their risks were assessed by a birdstrike ranking assessment system. The highest-risk species were Barn swallow (Hirundo rustica), Red-rumped swallow (H. daurica), Grey-headed lapwing (Vanellus cinereus), Pintail snipe (Gallinago stenura), Oriental skylark (Alauda gulgula), Little egret (Egretta garzetta), and Eurasian woodcock (Scolopax rusticola), whereas the lowest-risk species were Black-capped kingfisher (Halcyon pileata) and White-throated kingfisher (H. smyrnensis). Through a hierarchical cluster analysis, all species were classified as four groups: (1) the extremely high-risk group with a risk level between 84% and 100%, which includes bird species ranked from the 1st to the 16th, and is the priori group in birdstrike prevention; (2) the high-risk group with a risk level between 71% and 81%, which includes bird species ranked from the 17th to the 28th, and is the sub-prior group in birdstrikes; (3) the sub-high-risk group with a risk level between 60% and 69%, which includes bird species ranked from the 29th to the 43rd, and is the concern group in birdstrike prevention; (4) the low-risk group with a risk level between 60% and 69%, which includes bird species ranked from the 44th to the 60th, and is the negligible group in birdstrike prevention. Finally, the first 16 bird species with high-risk values, which are the main focus of birdstrike prevention, were categorized as six prevention groups by a hierarchical cluster analysis. Therefore, this study provides targeted implementations for birdstrike prevention at Huanghua International Airport, Changsha.

Abstract:Seasonal freeze–thaw cycle is a common phenomenon in the subalpine/alpine forest region, and may have a significant influence on the structure and function of soil animal community. To understand the characteristics and dynamics of soil animal community as well as its response to repeated freeze–thaw events in this region during onset of freezing, a field experiment was conducted to investigate the composition, abundance, and diversity of soil fauna in primary fir (Abies faxoniana) forest, fir and birch (Betula albosinensis) mixed forest and secondary fir (A. faxoniana) forest, which were three representative forests in the subalpine and alpine forest region in western Sichuan. Soil samples were collected from November 3 to November 27, 2008, which was defined as onset of freezing based on the simultaneous monitoring of soil temperature. Soil macrofauna were picked up by hand in the fields. Mesofauna were separated and collected from the soil samples by Baermann and Tullgren methods, respectively. By preliminary identification, 40,942 individuals were collected, which belonged to 7 phyla, 15 classes and 25 orders in the three sampling forests. 16,557, 14,669 and 9716 individuals were found in primary forest, mixed forest and secondary forest, respectively. In comparison with the mineral soil layer, the soil organic layer had higher density and groups of soil fauna. Furthermore, following the repeated freeze–thaw events, density and groups of soil fauna experienced a distinct decrease in both soil organic layer and mineral soil layer, and this trend in soil organic layer was more significant in the primary forest, owing to higher intense and more frequent freeze–thaw cycles in soil organic layer of the primary forest. The results revealed that soil animals were sensitive bio-indicators to environmental changes, such as repeated freeze–thaw events and dry–wet cycle. Meanwhile, the results also implied that the dynamics of the structure and function of soil animal community during the onset of freezing was of ecological significance to understand the wintertime ecological process in soils.

Abstract:In this work, the concentrations, temporal and spatial distributions and the relationship between biogenic silica (BSi) and primary productivity are discussed on the basis of the geochemistry character of BSi in the water–sediment system of the Wuliangsuhai Lake and Daihai Lake. The results show that the average concentrations of SiO₃^2- and BSi are 3.0 mg/L and 3.5 mg/g in the overlying water and sediments from the Wuliangsuhai Lake, respectively, while they are 1.0 mg/L and 7.5 mg/g, respectively, in the Daihai Lake. It is the uptake and assimilation of diatom phytoplankton which results in the significant difference of the SiO₃^2- concentrations between the two lakes, and the inputs of surface runoff is one of the important factors in impacting the spatial distributions of SiO₃^2- in the overlying water. The spatial distributions of BSi suggest the Si source of the two lakes and indicate the differences of eutrophication types and ancient primary producer between the two lakes. The eutrophication precesses and ancient primary productivity of diatom phytoplankton are reconstructed by applying the geochemistry information of BSi archived in the vertical concentration profiles in the two lake sediments. The geochemistry information of BSi well responds to the paleoenvironment and paleoclimate of the Daihai drainage basin indicating silicate limitation of primary productivity by diatoms phytoplankton in the Daihai Lake.

Abstract:A long term observation on biodiversity and biomass of benthic macroalgae in Point 1 of the intertidal zone of the Nanji Islands, Zhejiang were carried out during 1959–2007, including three phases, i.e. 1959–1965, 1980–1985 and 2000–2007. The results show that the species of the benthic macroalgae there disappeared by 41.7%, and decreasing trend of the biodiversity has been getting quick; the community structure clearly shifted, i.e. the proportion of subtropical and warm-temperate species increased, and that of cold-temperate species decreased in the benthic macroalgae assemblage, particularly the calcareous nullipore became an absolutely dominant group. In comparison with the second phase (1980–1985), during the third phase the average annual biomass of the benthic macroalgae decreased by 52.5%; the average spring and winter biomass decreased by 54.1% and 87.2%; while the average summer and autumn biomass increased by 11.1% and 3.2%, respectively. The causes of the decrease in the biodiversity have been discussed, and the authors considered that the climate change and increase in CO₂ concentration have been the main reasons to lead berserk growth of the nullipore, resulting in desertification tendency of the intertidal zone of the Nanji Islands.

Abstract:Understanding soil carbon fractions and their responses to the global warming is important for improving soil carbon management of natural altitudinal forest ecosystem. In this study, the contents of soil total organic carbon (SOC), soil labile organic carbon (LOC), and microbial biomass carbon (MBC) in soil upper layers (0–20 cm) were measured along a natural altitudinal transect in the north slope of Changbai Mountain. The results showed that under natural conditions the contents of SOC and LOC were largest in Betula ermanii forest (altitude 1996 m), moderate in spruce-fir forest (altitude 1350 m), and smallest in Korean pine mixed broad-leaf tree forest (altitude 740 m). MBC contents in different forest ecosystems decreased in the order of Betula ermanii forest, Korean pine mixed broad-leaf tree forest, and dark coniferous forest. In addition, the responses of SOC, LOC, and MBC to soil warming were conducted by relocating intact soil cores from high- to low-elevation forests for one year. As expected, the soil core relocation caused significant increase in soil temperature but made no significant effect on soil moisture. After one year incubation, soil relocation significantly decreased SOC contents, whereas the contents of LOC, MBC, and the ratios of LOC to SOC and MBC to SOC increased.

Abstract:Effect of bone char addition on the fractionation and bio-accessibility of lead (Pb) and Zinc (Zn) in combined contaminated soil was studied by batch soil column incubation experiment. Four treatments were designed: control (without bone char), 1%, 2% and 5% bone char addition (by weight). The results showed that all treatments with bone char addition could significantly decrease the concentration of HOAc extractable Pb (P < 0.05). Compared with the control the concentration of HOAc extractable Pb was decreased by 66.85%, 83.69% and 97.40%, respectively, in 1%, 2% and 5% bone char amended soils after 3 months incubation. The treatment with 5% bone char addition significantly decreased (P < 0.05) the concentration of HOAc extractable Zn by 47.80%, 43.63% and 41.35%, respectively, after 1, 2 and 3 months incubation. All treatments, including 1%, 2% and 5% bone char addition, significantly decreased (P < 0.05) the concentration of bio-accessible Pb after 3 months incubation, however, only the treatment with 5% bone char addition significantly decreased (P < 0.05) the concentration of bio-accessible Zn after 3 months incubation. The results highlighted the potential of bone char amendments to reduce the bioavailability of Pb and Zn in contaminated soil.