气候变化情景下中国自然植被净初级生产力分布

基于国际上较通用的Lund-Potsdam-Jena(LPJ)模型,根据中国自然环境特点对其运行机制进行调整,并重新进行了参数化,以B2情景气候数据作为主要的输入数据,以1961-1990年为基准时段,模拟了中国1991-2080自然植被净初级生产力(NPP)对气候变化的响应.结果表明:1961-1990年,中国自然植被的NPP总量为3.06 Pg C·a-1;1961-2080年,NPP总量呈波动下降趋势,且下降速度逐渐加快.在降水相对变化不大的条件下,平均温度的增加对我国植被生产力可能会产生一定的负面影响.NPP的空间分布从东南沿海向西北内陆呈逐渐递减趋势,在气候变化过程中,该格局基本没有太大变化.在东部NPP值相对较高地区,NPP值以减少为主,东北地区、华北东部和黄土高原地区的减少趋势尤为明显;在西部NPP值相对较低地区,NPP以增加趋势为主,青藏高原地区和塔里木盆地的表现尤为突出.随着气候变化的深入,东西部地区这种变化趋势的对比将越发明显.     

Tree diversity change in remaining primary mixed-broadleaved Korean pine forest under climate change and human activities

Studying biodiversity change in existing typical ecosystems of the world under possible global climate change and local human activities is important for diversity conservation. An adapted forest dynamics model is used to simulate tree diversity change of the remaining primary mixed-broadleaved Korean pine forest (RPMKPF) in northeast China under global climate change and local human activities for the next 50 years. Human activities include logging, which removes all big trees (DBH > 50 cm), removing all individuals of each single species and all species of each functional type (shade tolerant, shade intolerant and medium type tree species). As results for RPMKPF, the index of tree diversity decreases under climate change, but it increases significantly under a combination of climate change and logging. Removing all individuals of each single species significantly affects the tree diversity of the ecosystem. After the removal of shade tolerant species, both and _c indices of tree diversity experience a significant change. The index decreases significantly under climate change when shade intolerant or medium type tree species are removed, but the _c index does not change significantly. The results of this study have implications for tree diversity management in RPMKPF under climate change and human activities.     

The relationships between net primary productivity, human population density and species conservation

Aim In this study, I determine the relationships between net primary productivity (NPP), human population density, species richness and land use. I also examine the implications of human settlement patterns for species conservation. Location Australia. Methods I document the associations between NPP, human population density and the species richness of birds, butterflies and mammals using correlations and spatial regressions. I also assess changes in land‐use with NPP and population density, focussing particularly on protected areas. An initial exploration into the implications of the NPP‐population density relationship for regional conservation strategies is provided. Results Human population density increases with NPP suggesting that available energy may be a key driving force of human settlement patterns. The species richness of each taxonomic group and geographically restricted species also increases with NPP leading to substantial overlap between species diversity and populated regions. The percentage of land designated as minimal use decreases considerably with increasing human population density and NPP, while intensive agriculture is confined entirely to areas of high NPP. There are strong negative relationships between the size of Australia's National Parks and human population density and NPP. Small parks are often surrounded by relatively dense settlements, but have high average NPP, while large parks are mostly isolated and characterized by low productivity. There are no areas in the highest quartile of NPP that also occur in the most sparsely populated regions, presenting challenges for conservation strategies wanting to protect productive areas under the least threat of human development. Main conclusions Human population density and species richness respond similarly to variation in NPP, leading to spatial congruence between human settlements and productive, species rich regions. Planning strategies are required that minimize the potential threat posed by human development to diverse ecosystems and maximize the underlying productivity of protected areas. Reducing the level of threat may require stabilizing the size of the human population, while capturing larger areas of relatively high productivity in the conservation reserve system would lead to greater protection of local diversity.     

2000-2008年中国东北地区植被净初级生产力的模拟及季节变化

利用GLOPEM-CEVSA模型模拟并分析了中国东北地区2000-2008年植被净初级生产力(NPP)时空分布格局及其影响因素,并以4个森林生态站点(大兴安岭、老爷岭、凉水和长白山森林生态站)为例研究了东北地区森林NPP季节变化特征及其环境驱动.结果表明:2000-2008年,东北地区植被年均NPP为445 g C·m-2·a-1;整个研究区沿长白山山脉到小兴安岭山脉地区以及三江平原部分地区的NPP最高,沿长白山山脉到小兴安岭山脉西侧的辽河平原、松嫩平原东部、三江平原和大兴安岭地区次之,西部稀疏草原和荒漠地区的NPP最低.东北地区森林生态系统年均NPP最高,其次为灌丛、农田和草地,荒漠最低.森林生态系统中,针阔混交林年均NPP最大(722 g C·m-2·a-1),落叶针叶林年均NPP最小(451 g C·m-2·a-1).研究期间,森林NPP无显著年际变化,其中2007、2008年较往年NPP大幅增加,很可能与该地区期间气温上升有关(较往年偏高1 ℃=～2℃).东北地区森林自北向南生长季开始时间逐渐提前,生长季变长.     

Factors affecting the contribution by epiphytic algae to the primary productivity of an oligotrophic freshwater lake

A diatom-dominated population of epiphytic algae was studied in an oligotrophic lake to determine the factors which limit epiphyte growth and to measure their contribution to primary productivity. Algae were collected from plants growing at four sites in Lake George, N.Y., during the spring, summer, and fall of 1974. Samples were taken from 3 m, corresponding to the depth at which macrophytes were most productive. Algae exhibited an optimum temperature for H¹⁴CO₃^- uptake at 30 C, although the summer littoral lake temperature ranged from 18 to 25 C. Light saturation occurred at an intensity of 8,608 lux, approximating the environmental intensity at the depth from which algae were taken. Epiphytes exhibited their maximum photosynthetic capacity of 0.6 mg of carbon fixed/m² of macrophyte surface area per h in the early afternoon in mid-August. They assimilated approximately 5% as much inorganic carbon as the macrophytes from which they were taken. Epiphyte population densities followed the seasonal growth patterns of the macrophytes, with maximal leaf colonization remaining essentially constant relative to the leaf position on the plant. There was little change in density between sampling sites at any given time. Productivities of epiphytes from bottom leaves were 10-fold greater than those of epiphytes from top leaves. Addition of PO₄^-3, NO₃^-, NH₃, Si, and SO₄^-2 had no stimulatory effect on photosynthesis. Addition of HCO₃^- stimulated photosynthesis greater than 30%, suggesting that carbon may be a limiting nutrient for epiphytic algae in Lake George.     

Slowest to fastest: Extreme range in lichen growth rates supports their use as an indicator of climate change in Antarctica

Global temperature rise is suggested to be greater and more rapid in polar regions. There has been a clear temperature rise of 0.056 °C y⁻¹ in the Antarctic Peninsula and this has led to changes in higher plant extent and range. In the more extreme environments of the main continent the vegetation is scattered and composed of lichens and mosses. There is interest in the possible effects of global climate change on these communities acting through changes in temperature and precipitation. Lichens have been extensively used to date the substrates on which they are growing using the techniques of lichenometry. The slow growth and longevity of lichens particularly suites them for this use. We present evidence that there appears to be a substantial (two orders of magnitude) cline in lichen growth rate from the warmer, wetter and more productive Peninsula to the cold Dry Valleys at 77°S latitude. The differences in growth rate reflect the precipitation and temperature regimes at the different sites. The large range in growth rates coupled with the simplicity of measuring lichen growth using modern techniques suggests that this could be an excellent tool for the detection of climate change in continental Antarctica.     

Mountain forest growth response to climate change in the Northern Limestone Alps

Key message

Growth response to climate differs between species and elevation. Fir is the most drought-tolerant species. The mountain forests are robust to the climatic changes until now.

Abstract

Alpine mountain forests provide a wide range of ecological and socio-economic services. Climate change is predicted to challenge these forests, but there are still considerable uncertainties how these ecosystems will be affected. Here, we present a multispecies tree-ring network of 500 trees from the Berchtesgaden Alps (Northern Limestone Alps, Southeast Germany) in order to assess the performance of native mountain forest species under climate change conditions. The dataset comprises 180 spruce, 90 fir, 110 larch and 120 beech trees from different elevations and slope exposures. We analyse the species with respect to: (1) the general growth/climate response; (2) the growth reaction (GR) during the hot summer in 2003 and (3) the growth change (GC) resulting from increasing temperatures since the 1990s. Spruce is identified as the most drought-sensitive species at the lower elevations. Fir shows a high drought tolerance and is well suited with regard to climate change. Larch shows no clear pattern, and beech remains unaffected at lower elevations. The unprecedented temperature increase of the last decades did not induce any distinct GC. The mountain forests of the Berchtesgaden Alps appear to be robust within the climatic changes until now.     

Accuracy of the AVHRR vegetation index as a predictor of biomass,primary productivity and net CO2 flux

The Normalized Difference Vegetation Index (NDVI) or greenness index, based on the Advanced Very High Resolution Radiometer (AVHRR) aboard the NOAA-7 satellite, has been widely interpreted as a measure of regional to global vegetation patterns. This study provides the first rigorous, quantitative evaluation of global relationships between the NDVI and geographically representative vegetation data-bases, including field metabolic measurements and carbon-balance results from global simulation models. Geographic reliability of the NDVI is judged by comparing NDVI values for different surface types with a general global trend and by statistical analysis of relationships to biomass amounts, net and gross primary productivity, and actual evapotranspiration. NDVI data appear to be relatively reliable predictors of primary productivity except in areas of complex terrain, for seasonal values at high latitudes, and in extreme deserts. The strength of the NDVI-productivity relationship seems comparable to that of earlier climate-based productivity models. Little consistent relationship was found, across different vegetation types, between NDVI and biomass amounts or net biospheric CO₂ flux.Abbreviations AET= Actual Evapotranspiration - AVHRR= Advanced Very High Resolution Radiometer - GPP= Gross Primary Production - GVI= Global Vegetation Index - NDVI= Normalized Difference Vegetation Index - NPP= Net Primary Production     

Bats as an indicator of human activity in the paleolithic, using the example of denisova cave, northwestern Altai

Landscape and climatic changes in northwestern Altai at the end of the Middle Pleistocene were accompanied by a transformation in the taxonomic composition of the bat community and abundance of some species. The dynamics of the bat community is very important for the study of the activity of Paleolithic man. The high sensitivity of bats to human disturbance allowed the time of colonization and nature of usage of Denisova cave by humans to be recognized. In this respect, bats are a very important indicator of events in the surrounding ecosystem.     

1982-2009年东北多年冻土区植被净初级生产力动态及其对全球变化的响应

东北多年冻土区作为高纬度寒区之一,对全球变化较敏感.本文基于AVHRR和MODIS两种遥感数据源的归一化植被指数,应用CASA模型对1982-2009年东北多年冻土区植被净初级生产力(NPP)进行模拟.结果表明:1982-2009年,东北多年冻土区年均气温、年太阳辐射总量和年日照时数显著上升,年降水量显著下降,CO2浓度及其年增长率显著增大;植被年NPP呈显著的先增加后降低趋势,变化分异节点在1998年.研究期间,东北多年冻土区植被年均NPP总量为623 g C·m-2,植被年NPP空间分布差异明显.降水是该区生长季植被生长的主要影响因子,植被NPP对气候变化响应的空间异质性明显.土地利用变化通过改变土地覆被状况使植被NPP发生变化,影响了植被NPP的时空分布特征,植被NPP与CO2浓度呈显著正相关.多年冻土退化对植被NPP的影响随着各区域环境的不同而有所差异.多年冻土区植被NPP与年均地温呈显著正相关,与年最大冻土深度呈负相关.     

Implications of climate change for agricultural productivity in the early twenty-first century

This paper reviews recent literature concerning a wide range of processes through which climate change could potentially impact global-scale agricultural productivity, and presents projections of changes in relevant meteorological, hydrological and plant physiological quantities from a climate model ensemble to illustrate key areas of uncertainty. Few global-scale assessments have been carried out, and these are limited in their ability to capture the uncertainty in climate projections, and omit potentially important aspects such as extreme events and changes in pests and diseases. There is a lack of clarity on how climate change impacts on drought are best quantified from an agricultural perspective, with different metrics giving very different impressions of future risk. The dependence of some regional agriculture on remote rainfall, snowmelt and glaciers adds to the complexity. Indirect impacts via sea-level rise, storms and diseases have not been quantified. Perhaps most seriously, there is high uncertainty in the extent to which the direct effects of CO₂ rise on plant physiology will interact with climate change in affecting productivity. At present, the aggregate impacts of climate change on global-scale agricultural productivity cannot be reliably quantified.     

Pleistocene climate, phylogeny, and climate envelope models: an integrative approach to better understand species' response to climate change

Mean annual temperature reported by the Intergovernmental Panel on Climate Change increases at least 1.1°C to 6.4°C over the next 90 years. In context, a change in climate of 6°C is approximately the difference between the mean annual temperature of the Last Glacial Maximum (LGM) and our current warm interglacial. Species have been responding to changing climate throughout Earth's history and their previous biological responses can inform our expectations for future climate change. Here we synthesize geological evidence in the form of stable oxygen isotopes, general circulation paleoclimate models, species' evolutionary relatedness, and species' geographic distributions. We use the stable oxygen isotope record to develop a series of temporally high-resolution paleoclimate reconstructions spanning the Middle Pleistocene to Recent, which we use to map ancestral climatic envelope reconstructions for North American rattlesnakes. A simple linear interpolation between current climate and a general circulation paleoclimate model of the LGM using stable oxygen isotope ratios provides good estimates of paleoclimate at other time periods. We use geologically informed rates of change derived from these reconstructions to predict magnitudes and rates of change in species' suitable habitat over the next century. Our approach to modeling the past suitable habitat of species is general and can be adopted by others. We use multiple lines of evidence of past climate (isotopes and climate models), phylogenetic topology (to correct the models for long-term changes in the suitable habitat of a species), and the fossil record, however sparse, to cross check the models. Our models indicate the annual rate of displacement in a clade of rattlesnakes over the next century will be 2 to 3 orders of magnitude greater (430-2,420 m/yr) than it has been on average for the past 320 ky (2.3 m/yr).     

Application of the Red List Index as an indicator of habitat change

For the first time ever, the International Union for Conservation of Nature Red List Index for habitat types was calculated for an entire country, Finland. The RLIs were based on species threat assessments from 2000 and 2010 and included habitat definitions for all 10,131 species of 12 organism groups. The RLIs were bootstrapped to track statistically significant changes. The RLI changes of species grouped by habitats were negative for all habitat types except for forests and rural biotopes which showed a stable trend. Trends of beetles and true bugs were positive in rural and forest habitats. Other 16 observed trends of species group and habitat combinations were negative. Several trends observed were in accordance with studies focusing on particular taxa and habitats, and drivers for their change. This study demonstrates the usefulness of the RLI as a tool for observing habitat change based on species threat assessment data.     

Evaluating the net primary productivity in the grasslands of southern China from 2001 to 2010 using a new land portfolio assessment model

Grassland ecosystems play important roles in the global carbon cycle. The net primary productivity (NPP) of grassland ecosystems has become the hot spot of terrestrial ecosystems. To simulate the NPP in the grasslands of southern China, we built a land portfolio assessment (LPA) model. The LPA model was named according to the framework and principle of this model. From the framework of the model aspect, it was mainly driven by two parameters: leaf area index (LAI) and photosynthesis accumulation (PA). LAI is an extremely important structural characteristic of grassland and directly related to the exchange of energy, CO₂ and mass at a variety of scales. PA is represented by the amount of net photosynthetic production based on fixed-point observation. From the principle of the model aspect, it is represented by the inherent implication of NPP and a part of land portfolio assessment. The results showed that the NPP values in the study area had a decreasing trend from east to west and south to north and that the mean NPP was 320 g C m^?2 year^?1 from 2001 to 2010. Correlations analysis showed that the correlation coefficient (r) between NPP and highest monthly mean temperature of a year was the maximum (0.6422), and the r value between NPP and annual precipitation was the minimum (0.3821). Using trial and error, the LPA model accurately simulated the NPP dynamics of southern China’s grassland ecosystem, and the results were biologically realistic.     

Phytoplankton and its contribution to primary productivity in two coral reef areas of French Polynesia

A study of phytoplankton productivity and related parameters was carried out in two fringing and barrier reef systems around Moorea island (Tiahura lagoon) and Tahiti (Vairao lagoon), Society Islands, during July–August 1974.In Tiahura lagoon, which is the narrower and the shallower, phytoplankton standing crop and production are extremely low; photosynthetic assimilation, as measured in situ by the ¹⁴C method, ranges from 4 to 27 mg C m^?2 day^?1, presumably less than in the impoverished open ocean, but it is surprisingly high at a station just outside the barrier reef (645 mg C m^?2 day^?1) as the result of some island mass effect. As compared to the latter station, the lagoon shows a ten-times increase in particle content and glucose uptake, and a higher percentage of decomposition products of plant pigments. These data support the concept that, in such environments where benthic primary producers prevail, phytoplankton may have lost its ‘usual’ rôle in the aquatic food web.Vairao lagoon, a deeper and wider one, subjected to a greater extent to land fertilization, is more productive (103–420 mg C m^?2 day^?1). Considering this difference, as well as the considerable range of phytoplankton production in coral reef areas of the world, the need for a trophic classification of such ecosystems is emphasized.     

Net primary production, carbon storage and climate change in Chinese biomes

Net primary production (NPP) and leaf area index (LAI) of Chinese biomes were simulated by BIOME3 under the present climate, and their responses to climate change and doubled CO₂ under a future climatic scenario using output from Hadley Center coupled ocean‐atmosphere general circulation model with CO₂ modelled at 340 and 500 ppmv. The model estimated annual mean NPP of the biomes in China to be between 0 and 1270.7 gC m^‐2 yr^‐1 at present. The highest productivity was found in tropical seasonal and rain forests while temperate forests had an intermediate NPP, which is higher than a lower NPP of temperate savannas, grasslands and steppes. The lowest NPP occurred in desert, alpine tundra and ice/polar desert in cold or arid regions, especially on the Tibetan Plateau. The lowest monthly NPP of each biome occurred generally in February and the highest monthly NPP occurred during the summer (June to August). The annual mean NPP and LAI of most of biomes at changed climate with CO₂ at 340 and 500 ppmv (direct effects on physiology) would be greater than present. The direct effects of carbon dioxide on plant physiology result in significant increase of LAI and NPP. The carbon storage of Chinese biomes at present and changed climates was calculated by the carbon density and vegetation area method. The present estimates of carbon storage are totally 175.83 × 10¹² gC (57.57 × 10¹² gC in vegetation and 118.28 × 10¹² gC in soils). Changed climate without and with the CO₂ direct physiological effects will result in an increase of carbon storage of 5.1 and 16.33 × 10¹², gC compared to present, respectively. The interaction between elevated CO₂ and climate change plays an important role in the overall responses of NPP and carbon to climate change.     

Relationships between forest fine and coarse woody debris carbon stocks across latitudinal gradients in the United States as an indicator of climate change effects

Coarse and fine woody materials (CWD and FWD) are substantial forest ecosystem carbon (C) stocks. There is a lack of understanding how these detritus C stocks may respond to climate change. This study used a nation-wide inventory of CWD and FWD in the United States to examine how these C stocks vary by latitude. Results indicate that the highest CWD and FWD C stocks are found in forests with the highest latitude, while conversely the lowest C stocks are found in the most southerly forests. CWD and FWD respond differently to changes in latitude with CWD C stocks decreasing more rapidly as latitude decreased. If latitude can be broadly assumed to indicate temperature and potential rate of detrital decay, it may be postulated that CWD C stocks may be at the highest risk of becoming a net C source if temperatures increase. The latitude at which CWD and FWD C stocks roughly equal each other (equilibrium point) may serve as an indicator of changes in C stock equilibrium under a global warming scenario. Given the complex relationships between detrital C stocks, biomass production/decay, and climatic variables, further research is suggested to refine this study's indicator.