集成生态软约束机制的城市空间形态时空演变情景模拟

自然生态空间是生物栖息繁衍的场所,生物和非生物成分组成的生态系统为人类提供赖以生存的生态系统服务。新时期绿色发展战略下高质量国土空间资源配置需要科学探究生态空间约束的作用机理。以泉州市为研究区,选取水源涵养、土壤保持和生物多样性等生态系统服务为生态因子,基于有序加权平均(OWA)算法构建城市扩张的生态软约束机制。以2005年土地利用现状为起始值,综合考虑自然人文等驱动力因素,基于构建的OWA-FLUS模型对泉州市2020年和2035年土地利用时空演化动态开展多情景模拟预测。结果表明：(1)策略控制因子δ=0.000001下,OWA-FLUS模型的总体精度和Kappa系数达到95.94%和0.7742,FoM和FoM_urban比FLUS模型分别提高了4.95%和7.17%,基于提升潜力空间的MICE功效指数分别为0.059和0.102。(2)当δ值从0向1000变化时,OWA-FLUS模型的模拟精度逐渐下降。对比δ=1.0的赋权线性组合(WLC)生态约束,δ=0.000001下的OWA模拟的FoM_urban提升了5.70%。(3)2035年基准...     

What's going to be on the menu with global environmental changes?

Ongoing anthropogenic change is altering the planet at an unprecedented rate, threatening biodiversity, and ecosystem functioning. Species are responding to abiotic pressures at both individual and population levels, with changes affecting trophic interactions through consumptive pathways. Collectively, these impacts alter the goods and services that natural ecosystems will provide to society, as well as the persistence of all species. Here, we describe the physiological and behavioral responses of species to global changes on individual and population levels that result in detectable changes in diet across terrestrial and marine ecosystems. We illustrate shifts in the dynamics of food webs with implications for animal communities. Additionally, we highlight the myriad of tools available for researchers to investigate the dynamics of consumption patterns and trophic interactions, arguing that diet data are a crucial component of ecological studies on global change. We suggest that a holistic approach integrating the complexities of diet choice and trophic interactions with environmental drivers may be more robust at resolving trends in biodiversity, predicting food web responses, and potentially identifying early warning signs of diversity loss. Ultimately, despite the growing body of long-term ecological datasets, there remains a dearth of diet ecology studies across temporal scales, a shortcoming that must be resolved to elucidate vulnerabilities to changing biophysical conditions.     

Rainforest conversion to plantations fundamentally alters energy fluxes and functions in canopy arthropod food webs

Tropical rainforests around the world are rapidly being converted into cash crop agricultural systems. The associated massive losses of plant and animal species lead to changes in arthropod food webs and the energy fluxes therein. These changes are poorly understood, in particular in the extremely biodiverse canopies of tropical ecosystems. Using canopy fogging followed by stable isotope and energy flux analyses, we show that land-use conversion from rainforest to rubber and oil palm plantations not only causes a drastic reduction in energy fluxes of up to 75%, but also shifts fluxes among trophic groups. While rainforest featured high levels of both herbivory and algae-microbivory, and a balanced ratio of herbivory to predation, relative fluxes were shifted towards predation in rubber and towards herbivory in oil palm plantations, indicating profound shifts in ecosystem functioning. Our results highlight that the ongoing loss of animal biodiversity and biomass in tropical canopies degrades animal-driven functions and restructures canopy food webs.     

Changes in soil carbon inventories following cultivation of previously untilled soils

Cultivation of previously untilled soils usually results in release of carbon from the soil to the atmosphere, which can affect both soil fertility locally and the atmospheric burden of CO₂ globally. Generalizations about the magnitude of this flux have been hampered by a lack of good quality comparative data on soil carbon stocks of cultivated and uncultivated soils. Using data from several recent studies, we have reexamined the conclusions of previous reviews of this subject. The data were divided into subsets according to whether the soils were sampled by genetic horizon or by fixed depths. Sampling by fixed depths appears to underestimate soil C losses, but both subsets of data support earlier conclusions that between 20% and 40% of the soil C is lost following cultivation. Our best estimate is a loss of about 30% from the entire soil solum. Our analysis also supports the conclusion that most of the loss of soil C occurs within the first few Years (even within two Years in some cases) following initial cultivation. Our analysis does not support an earlier conclusion that the fractional loss of soil carbon is positively correlated to the amount of carbon initially present in the uncultivated soil. We found no relation between carbon content of uncultivated soil and the percentage lost following cultivation.     

Net changes in regional woody vegetation cover and carbon storage in Texas Drylands, 1937–1999

Although local increases in woody plant cover have been documented in arid and semiarid ecosystems worldwide, there have been few long‐term, large‐scale analyses of changes in woody plant cover and aboveground carbon (C) stocks. We used historical aerial photography, contemporary Landsat satellite data, field observations, and image analysis techniques to assess spatially specific changes in woody vegetation cover and aboveground C stocks between 1937 and 1999 in a 400‐km² region of northern Texas, USA. Changes in land cover were then related to topo‐edaphic setting and historical land‐use practices. Mechanical or chemical brush management occurred over much of the region in the 1940–1950s. Rangelands not targeted for brush management experienced woody cover increases of up to 500% in 63 years. Areas managed with herbicides, mechanical treatments or fire exhibited a wide range of woody cover changes relative to 1937 (?75% to + 280%), depending on soil type and time since last management action. At the integrated regional scale, there was a net 30% increase in woody plant cover over the 63‐year period. Regional increases were greatest in riparian corridors (33%) and shallow clay uplands (26%) and least on upland clay loams (15%). Allometric relationships between canopy cover and aboveground biomass were used to estimate net aboveground C storage changes in upland (nonriparian) portions of regional landscapes. Carbon stocks increased from 380 g C m^?2 in 1937 to 500 g C m^?2 in 1999, a 32% net increase across the 400 km² region over the 63‐year period. These plant C storage change estimates are highly conservative in that they did not include the substantial increases in woody plant cover observed within riparian landscape elements. Results are discussed in terms of implications for ‘carbon accounting’ and the global C cycle.     

Maximum impacts of future reforestation or deforestation on atmospheric CO2

There is scope for land‐use changes to increase or decrease CO₂ concentrations in the atmosphere over the next century. Here we make simple but robust calculations of the maximum impact of such changes. Historical land‐use changes (mostly deforestation) and fossil fuel emissions have caused an increase in atmospheric concentration of CO₂ of 90 ppm between the pre‐industrial era and year 2000. The projected range of CO₂ concentrations in 2100, under a range of emissions scenarios developed for the IPCC, is 170–600 ppm above 2000 levels. This range is mostly due to different assumptions regarding fossil fuel emissions. If all of the carbon so far released by land‐use changes could be restored to the terrestrial biosphere, atmospheric CO₂ concentration at the end of the century would be about 40–70 ppm less than it would be if no such intervention had occurred. Conversely, complete global deforestation over the same time frame would increase atmospheric concentrations by about 130–290 ppm. These are extreme assumptions; the maximum feasible reforestation and afforestation activities over the next 50 years would result in a reduction in CO₂ concentration of about 15–30 ppm by the end of the century. Thus the time course of fossil fuel emissions will be the major factor in determining atmospheric CO₂ concentrations for the foreseeable future.     

Use of remote sensing and geographical information systems to estimate green space surface-temperature change as a result of urban expansion

A combined approach of remote sensing (RS) and geographical information systems (GIS) was used in this study to identify the impact on urban surface radiant temperature (SRT) of urban green-space change. Urban SRT increases as green-space area is converted into non-green-space area. Also, well preserved green space and newly connected green space contribute to a decrease of the SRT. Seoul Metropolitan area is rapidly expanding. Existing urban SRT studies have, however, mainly been conducted for Seoul City. The most rapidly expanding area in Korea is now the Seoul suburban area, for example the Mt Gwanggyo area. Although changes of SRT and normalized difference vegetation index (NDVI) as a result of land-use change have been measured in many other studies, the results in these studies were derived from data from different seasons. Also, these studies did not examine a newly expanding area. Considering these problems, the same seasonal multitemporal data were used in this study to derive the SRT change for the same season in different years. This study confirmed the importance of effective management and location of urban green space for urban SRT mitigation. Ultimately, the impact on urban SRT of urban green-space change should be regarded as an important factor in urban planning.     

Projected changes in mineral soil carbon of European croplands and grasslands, 1990–2080

We present the most comprehensive pan‐European assessment of future changes in cropland and grassland soil organic carbon (SOC) stocks to date, using a dedicated process‐based SOC model and state‐of‐the‐art databases of soil, climate change, land‐use change and technology change. Soil carbon change was calculated using the Rothamsted carbon model on a European 10 × 10′ grid using climate data from four global climate models implementing four Intergovernmental Panel on Climate Change (IPCC) emissions scenarios (SRES). Changes in net primary production (NPP) were calculated by the Lund–Potsdam–Jena model. Land‐use change scenarios, interpreted from the narratives of the IPCC SRES story lines, were used to project changes in cropland and grassland areas. Projections for 1990–2080 are presented for mineral soil only. Climate effects (soil temperature and moisture) will tend to speed decomposition and cause soil carbon stocks to decrease, whereas increases in carbon input because of increasing NPP will slow the loss. Technological improvement may further increase carbon inputs to the soil. Changes in cropland and grassland areas will further affect the total soil carbon stock of European croplands and grasslands. While climate change will be a key driver of change in soil carbon over the 21st Century, changes in technology and land‐use change are estimated to have very significant effects. When incorporating all factors, cropland and grassland soils show a small increase in soil carbon on a per area basis under future climate (1–7 t C ha^?1 for cropland and 3–6 t C ha^?1 for grassland), but when the greatly decreasing area of cropland and grassland are accounted for, total European cropland stocks decline in all scenarios, and grassland stocks decline in all but one scenario. Different trends are seen in different regions. For Europe (the EU25 plus Norway and Switzerland), the cropland SOC stock decreases from 11 Pg in 1990 by 4–6 Pg (39–54%) by 2080, and the grassland SOC stock increases from 6 Pg in 1990 to 1.5 Pg (25%) under the B1 scenario, but decreases to 1–3 Pg (20–44%) under the other scenarios. Uncertainty associated with the land‐use and technology scenarios remains unquantified, but worst‐case quantified uncertainties are 22.5% for croplands and 16% for grasslands, equivalent to potential errors of 2.5 and 1 Pg SOC, respectively. This is equivalent to 42–63% of the predicted SOC stock change for croplands and 33–100% of the predicted SOC stock change for grasslands. Implications for accounting for SOC changes under the Kyoto Protocol are discussed.     

A dendroecological reconstruction of use by Saami of Scots Pine (Pinus sylvestris L.) inner bark over the last 350 years at Sädvajaure,N. Sweden

The historical use of Scots Pine (Pinus sylvestris L.) inner bark by the Saami near Lake Sädvajaure, N. Sweden was studied with dendro-ecological methods. Damming of the lake for hydroelectric power enabled destructive sampling of all pines with scars from bark peeling in an area of 870 ha. A total of 111 dead and live pines with 136 bark peelings were found. Stem-sections were taken for cross-dating to determine the precise peeling year and season. The oldest peeling was dated to 1618, which is the oldest reported evidence of Saami use of inner bark. No bark peelings were made after 1870 in the studied area which coincides with a shift to more extensive reindeer herding, and with colonization by Swedish farmers in the area. The regular use of inner bark over time and the absence of peeling peaks in known agrarian famine years support the hypothesis that inner bark was used regularly, and not only as an emergency food. Changes in spatial peeling activity around the lake is interpreted as temporal changes in nomadic fishing activity. We conclude that tree ring studies can provide valuable information about former mobile use of natural resources by Saami in boreal forest landscapes.