高级生态学系列讲座之二.ppt

北方草地生态系统对全球变化响应研究（兼谈生态学sci论文的写作与发表）,北京林业大学林学院,报告内容,研究背景 研究地点 三个研究案例 土地利用对土壤碳氮储量的影响 土地利用对局域尺度物种多样性与生产力关系的影响 降水增加与土壤有机碳添加对地下碳循环的影响 生态学sci论文写作和发表,报告内容,研究背景 研究地点 三个研究案例 土地利用对土壤碳氮储量的影响 土地利用对局域尺度物种多样性与生产力关系的影响 降水增加与土壤有机碳添加对地下碳循环的影响 生态学sci论文写作和发表,研究背景,欧亚草原生态系统 草地生态系统占国土面积的40，其中约3.13亿公顷分布于北方温带气候区 全球气候变化与土地利用变化 国家在减缓碳排放中需要履行的义务,报告内容,研究背景 研究地点 三个研究案例 土地利用对土壤碳氮储量的影响 土地利用对局域尺度物种多样性与生产力关系的影响 降水增加与土壤有机碳添加对地下碳循环的影响 生态学sci论文写作和发表,研究地点,内蒙古多伦县。 地理范围：115o50116o55e，41o4642o39n 海拔：1 150 1 800 m之间 年均降水量为385.5 mm，潜在蒸发量为1 748 mm，其中68月降水量占全年的67 年均气温为1.6，最暖月(7月)平均气温为18.7 ，最冷月(1月)平均气温为-18.3 ，无霜期100 d左右，10 积温为1 917.9 天然植被以典型草原为主，优势植物包括羊草、克氏针茅、冰草和冷蒿等 农田以小麦、燕麦、苦荞麦、青贮玉米等为主,野外调查,凋落物分解,样方调查,洗根,物种调查,报告内容,研究背景 研究地点 三个研究案例 土地利用对土壤碳氮储量的影响 土地利用对局域尺度物种多样性与生产力关系的影响 降水增加与土壤有机碳添加对地下碳循环的影响 生态学sci论文写作和发表,土地利用对土壤碳氮储量的影响,research objectives,quantify the influence of different land-uses on soil carbon and nitrogen stores; identify the suitable land-use and management options for carbon sequestration and socio-economic activities; examine the inter-relationship between carbon and nitrogen stores and productivity as influenced by land-uses for the semi-arid grassland ecosystems of northern china.,purpose of the study,to provide regionally based, policy-relevant information on the impact of land-use change on carbon stock as called for by the international carbon cycle research communities (gcp 2003), and to identify carbon sequestration potential of the region through improved land management.,研究方法,样地设置 6种土地利用类型 每种土地利用类型4个30x30m标准样方 测定指标 植被地上生物量，anpp 地表凋落物生物量 土壤分层根系生物量 土壤容重 植物组织和土壤的碳、氮含量,六种不同土地利用类型,围封草地,刈割草地,放牧草地,人工草地,农田,弃耕地,放牧草地,key results (1),among the six land-use types, anpp varied markedly and highly significantly (p apflgemwfg; the anpp for the cp was between nearly five- to more than 18-folds greater than other five land use types.,key results (2),total belowground soil nitrogen stores ranged from 0.4 kg n m2 for the fg to 0.8 kg n m2 for the ap; the cp only ranked the third in the total belowground carbon stores and the fifth in the total belowground nitrogen stores.,key results (3),among the carbon pools belowground, litter was most variable across the land-use types; the ap was ranked the highest in carbon store for all the three pools; the lowest carbon store was displayed by the cp in litter and roots.,key results (4),patterns of nitrogen store with land-use were slightly different from the carbon store such that nitrogen stores showed less variation in roots and som across most of the land-use types; the ground-floor litter nitrogen store varied greatly among the land-use types, and was greatest in the ap and least in the cp; the ap had the greatest nitrogen store in both roots and som; the least nitrogen store was displayed by the ap in roots, and the fg in som.,key results (5),with exception of the cp, soc and son stores apparently increased with anpp across the land-use types; within the same land-use types such trend did not seem to exist.,key findings,among the six land-use types, alfalfa pasture clearly ranks the best from perspectives of feed-stock and soil carbon and nitrogen stores; the state of free-grazing sites suggested apparent overgrazing and severe land degradation; restoring severely degraded and overgrazed grasslands could potentially increase soil organic carbon and nitrogen stores by more than 55%; conversion from the native grasses to alfalfa could potentially double the aboveground biomass production, and further increase soil organic carbon and nitrogen stores by more than 20%.,issues to consider,despite of the promising outlook for the alfalfa pastures, large-scale conversion of the native natural vegetation to alfalfa pastures should be treated with caution as alfalfa has not been proven to survive the extreme events of low winter temperatures and drought. uncertainty with diseases in long-term alfalfa systems may also constrain the wide use of alfalfa hay in the region; mechanized mowing is not necessarily a long-term solution to carbon sequestration for the purpose of mitigating global climate change due to the costs of fossil fuel consumption; diversity in land-uses in the agro-pastoral ecotone of northern china should be viewed as necessary for addressing issues concerning both regional productivity and global climate change,major conclusion,through improved management and land-use conversion for better productivity, the agro-pastoral ecotone of northern china could be utilized as a significant carbon sink in the context of mitigating global climate change while maintaining adequate productivity for servicing the regional socio-economic development.,报告内容,研究背景 研究地点 三个研究案例 土地利用对土壤碳氮储量的影响 土地利用对局域尺度物种多样性与生产力关系的影响 降水增加与土壤有机碳添加对地下碳循环的影响 生态学sci论文写作和发表,土地利用对局域尺度物种多样性与生产力关系的影响,research objective,to determine how land use affects the diversityproductivity relationship in semi-arid steppe ecosystems. hypothesis: the mode and intensity of disturbance due to anthropogenic activities contributed to the relationship between species diversity and community productivity,研究方法,样地设置 三种土地利用类型 每种土地利用类型4个30x30m标准样地 测定指标 aboveground biomass plant abundance species composition and richness cover,物种调查,样方调查,土地利用类型,围封草地,刈割草地,放牧草地,measures of biodiversity traits,measurement of species frequency,on each site, species frequencies were measured from 25 randomly placed quadrats (0.50.5 m) by recording the presence of species within each quadrat. species frequency was expressed as the proportion of quadrats containing a given species (duncan et al . 1997).,key results (1),the values of pielou and shannonwiener indices and species richness were significantly higher on both types of grazing exclusion plot (ge and mw) than on the fg plots, while the mw site had a markedly higher level of plant abundance than the other two land-use types (ge and fg).,key results (2),pearsons correlation analysis revealed a significant and positive correlation between anpp and shannonwiener index on the mw site, and a significant but negative correlation on the fg site.,key results (3),the relationship between anpp and species richness can be best described as an exponential growth function on the ge and mw plots, and as an exponential decay function on the fg plots.,key results (4),compared with fg plots, the ge and mw plots were characterized by significantly (p0.05) greater frequency of liliaceae species (allium bidentatum, allium tenuissimum, allium neriniflorum, allium ramosum, allium senescens), most of which grow close to the ground surface with low productivity; the fg plots had significantly (p0.05) greater numbers of legume species (oxytropis glabra, melissitus ruthenica, astragalus scaberrimus, astragalus galactites), and a higher frequency of the rhizomatous species, especially carex duriuscula, than the other two sites; the ge and mw plots differed from the fg plots by displaying greater importance of pf species and lesser importance of ss species in terms of relative contributions to anpp, plant abundance and cover.,key results (5),on both ge and mw plots, above-ground production was comprised mainly of the pb, pf and ss functional groups, pf being the most dominant; whereas on the fg plots, above-ground production was predominantly and equally comprised of the pb and ss functional groups; the ab functional group contributed a meaningful fraction of total anpp only on ge plots.,key results (6),on the fg plots, above-ground production of the pb functional group increased with species richness, whereas above-ground production of the ss functional group decreased with species richness.,key results (7),for plant abundance, the pf functional group was most dominant on ge and mw plots, followed by the pr and pb functional groups; on the fg plots, the pr functional group ranked highest and pb next to highest, followed by pf; the pf functional group on the mw plots had much higher abundance than on plots of the other two land-use types.,key results (8),plant cover was almost the same for the pb, pf and ss functional groups on the ge plots, and about equal for the pf and ss functional groups on the mw plots, but was dominated mainly by the ss functional group on the fg plots.,key findings,at the local scale, the relationship between biodiversity and productivity could be strongly affected by the mode and severity of disturbance reflected in different land-use types in the semi-arid steppe ecosystems; precise mechanisms underlying the relationship between species diversity and productivity can be very complex, and that the mode and severity of disturbance are critical in regulating such a relationship; the mode and severity of disturbance are important factors for interpreting the relationship between species diversity and productivity in semi-arid steppe ecosystems.,报告内容,研究背景 研究地点 三个研究案例 土地利用对土壤碳氮储量的影响 土地利用对局域尺度物种多样性与生产力关系的影响 降水增加与土壤有机碳添加对地下碳循环的影响 生态学sci论文写作和发表,降水增加与土壤有机碳添加对地下碳循环的影响,research objectives,to determine whether microbes in the grasslands of northern china are energy-limited (in which case increased litter inputs are unlikely to result in soil c sequestration) or resource-limited; to determine whether soc addition and irrigation stimulate plant and microbial biomass and their respiration rates; to determine whether the enhanced inputs of water and soc influence the temperature sensitivity of soil respiration.,研究方法,实验设计 40 1x1 m plots 4 pom addition rates (equivalent to 0, 60, 120 and 240 g c m2) to 10-20cm soil layer under either natural precipitation or with 50% increase in summer precipitation 5 replications 测定指标 soil co2 efflux aboveground and root biomass soil microbial biomass and activity soil organic c content,key results (1),the effects of irrigation and enhanced soil c inputs on soc were marginal to absent; irrigation significantly increased smb-c and sma in both the 010 cm and the 1020 cm soil layers; enhanced soil c inputs did not increase smb-c and sma in the 010 cm soil layer, but significantly increased smb-c and sma in the 1020 cm soil layer.,key results (2),enhanced soil c inputs significantly increased aboveground biomass and root biomass in the 1020 cm soil layer, but did not affect root biomass in the 010 cm soil layer; irrigation had very little effect on standing biomass.,key results (3),irrigation and enhanced soil c inputs significantly increased cumulative soil c efflux,key results (4),in all plots, rs was strongly related to soil temperature; irrigation and enhanced soil c inputs significantly increased rs10c and q10.,key results (5),rs10c varied significantly with time, and displayed peak values in mid-july regardless of levels of subsoil pom addition and precipitation,key findings,increasing rates of subsoil pom ad