Age and Origin of Upland block Fields on Melville Peninsula, Eastern Canadian Arctic

Block fields have developed on gently graded uplands of granite and gneiss on central and southern Melville Peninsula. The location of block fields is not controlled by elevation, but rather by areas covered by cold–based ice during the last glaciation. Block fields consist either of angular boulders, sorted circles 3–4 m across having blocky rims and central areas of weathered grus, concentrations of openwork boulders, or in the southeast, of immature bouldery till. The block fields are primarily relict features predating the last glaciation, produced by weakening of bedrock by weathering along joints, followed by frost heave, although some block fields have been modified by meltwater from regional glacier down–wasting. Frost processes are active in the modern environment but the extent of riven bedrock and the size of recent patterned ground forms on postglacial surfaces are insufficient to account for the forms in the block fields.     

Raised beach deposits and new 14C ages from Picepynten, Prins Karls Forland, Western Svalbard

This note reports the occurrence of two generations of 14C dated raised beach deposits at Pricepynten. southern Prins Karls Forland, western Svalbard, dated to < 12 Kya and >30 Kya. In addition two new 14C ages of ca. 9.2 and 1.8 Ky are presented from Myrilus eclulis and a buried peat deposit, respectively.     

Ice-rafted detritus events in the Arctic during the last glacial interval, and the timing of the Innuitian and Laurentide ice sheet calving events

Ice-rafted detritus (IRD) layers in the Arctic Ocean not only indicate the source of this detrital sediment, but give insights into the ice drift and ice sheet history. Detrital sand-sized Fe oxide mineral grains that are matched to precise sources using the microprobe chemical fingerprint of each grain, along with elevated coarse IRD abundance and radiocarbon ages, are used to define IRD peaks from the Innuitian and Arctic portions of the Laurentide ice sheets. Because grains from these two areas can be entrained by sea ice from the shelves just offshore of the calving areas, peaks in these grains must be correlated to coarse IRD to identify iceberg calving events, and to distinguish them from sea-ice rafting. The sequence of IRD peaks deposited by icebergs from these two ice sheets indicate that both ice sheets calved bergs at accelerated numbers, six or seven times, from 11 to 36 Kya. The relatively short times between most of these IRD events suggest that the ice sheets did not completely collapse with each IRD event, except the last event. Although there is some indication that one ice sheet may have begun calving bergs before the other, the resolution of the Arctic cores does not allow definitive determination of this. This emphasizes the need for higher resolution cores from the central Arctic, as well as from near the terminus of large Pleistocene ice sheets. Sea-ice rafting occurs throughout the last glacial stage, even during some glacial IRD events, as indicated by Fe grains from non-glacial sources.     

The late Quaternary development of three ancient tarns on southwestern Cumberland Peninsula, Baffin Island, Arctic Canada: paleolimnological evidence from diatoms and sediment chemistry

Sediment diatom and chemical analyses of cores from three poorly buffered extra-glacial lakes on the northeastern margin of the Canadian Shield (Cumberland Peninsula, Baffin Island) record interactions between aquatic and terrestrial spheres that were influenced by late Quaternary climatic conditions. Although differences exist between each of the lakes, notably with regards to the intensity of pre-Holocene catchment erosion and the timing of the onset of organic sedimentation, an underlying pattern of lake ontogeny, common to all three lakes, is identified. Although intensified watershed erosion characterized the Late Wisconsinan and Neoglacial cold periods, the lakes nonetheless remained viable ecosystems at these times. Sudden catchment stabilization during the late-glacial to earliest Holocene is associated with incipient organic sedimentation. Lake-water pH increased at this time, likely in response both longer base cation residence times as lake flushing rates decreased, and enhanced alkalinity production from sediment biogeochemical reactions. Subsequently, as the catchments remained stable during the productive early Holocene (c.9–7 ka BP), then gradually received a renewed increase of minerogenic sedimentation, the breakdown of sources of lake alkalinity resulted in natural acidification. Burial of cation-rich mineral sediments and the loss of permanent sedimentary sinks for the products of microbial reduction likely impeded within-lake alkalinity production, and catchment-derived base cations appeared ineffective in curtailing pH declines. The general nature of the Holocene development of these lakes is similar to that observed elsewhere on crystalline terrains, following deglaciation. Our data therefore suggest that catchment glaciation is not a necessary precursor for models of lake development characterized by initial base cation enrichment and subsequent gradual acidification.     

Morphometric Analysis on the Size, Shape and Areal Distribution of Glacial Cirques in the Maritime Alps (Western French-Italian Alps)

The morphometry of 432 glacial cirques in the Maritime Alps (Western French‐Italian Alps), studied over several years of fieldwork, was analysed with the use of a geographical information system. Some of the parameters automatically evaluated from digital elevation models required an objective and relatively new definition. In particular, cirque length was measured along a line that, from the threshold midpoint, splits the cirque into two equivalent surfaces; cirque width was automatically drawn as the longest line inscribed in the cirque and perpendicular to the length line. Significant correlations were found among the different factors and parameters analysed. In particular, cirque shape analysis showed that cirques develop allometrically in the three dimensions, i.e. more in length and width than in altitudinal range. Nevertheless cirques of the Maritime Alps have a regular, almost circular shape (mean L/W value = 1.07). The correlations among length, width and area are all very high (r²= 0.8–0.9). In terms of size, cirques show a wide range in area from 0.06 to 5.2 km² with a mean value of 0.4 km². The largest cirques are found on SSW‐facing slopes and at high elevations. Small cirques can be found at all altitudes but all those at high elevation are part of compound cirques at the main head valleys. Most cirques (37%) are characterized by a northern aspect; NE and SW are also frequent directions.     

北半球积雪/海冰面积与温度相关性的差异分析

积雪和海冰的时空变化对区域以及全球的气候、水文具有重要影响。基于雪冰数据和NCEP再分析气温数据,利用MK检验、滞后分析等方法,分析了积雪、海冰的时空变化特征及其与温度的相关特征。结果表明：1979-2013年,北半球积雪区、北极圈的年均温度呈显著上升的趋势,而积雪面积和海冰面积呈显著下降的趋势。在大部分地区,积雪覆盖频率随着温度的上升呈显著减少的趋势,但在中国长江中下游、青藏高原等局部地区,积雪覆盖频率随着温度的上升呈显著增加趋势。在大部分的近陆地海域,海冰覆盖频率随着温度的上升呈显著下降趋势。超前时间1~2个月的温度与海冰面积的负相关性最高。超前1~4个月的温度与积雪面积的负相关性最高。温度对海冰的影响时间比对积雪的影响时间长1~2个月。温度变化对海冰和积雪的影响存在一致性,但积雪和海冰对温度的响应时间存在差异,具有空间变异性。     

Exploring the relationships between post-fire vegetation regeneration dynamics,topography and burn severity: A case study from the Montane Cordillera Ecozones of Western Canada

In this study the relationships between vegetation regeneration dynamics to topography and burn severity for a Canadian landscape were investigated using freely available Earth Observation (EO) imagery from Landsat TM sensor. The Okanagan Mountain Park, located in the Montane Cordillera Ecozones of Western Canada at which a fire occurred in 2003, was used as a case study. First, vegetation regeneration dynamics were quantified for a period of 8 years following the fire event based on a chronosequence analysis of the Normalized Difference Vegetation Index (NDVI) and the Regeneration Index (RI). The spatio-temporal patterns of post-fire NDVI from each image date were statistically compared to the pre-fire pattern to determine the extent to which the pre-fire spatial pattern was re-established and also the rate of recovery. Subsequently, the relationships of vegetation regrowth to both topography and burn severity was quantified using a series of additional statistical metrics. Burn severity was derived from the differenced Normalized Burn Ratio (dNBR) index computed from the Landsat TM images. Information on topography properties of the region was obtained from the ASTER global operational product.NDVI and RI analysis indicated a moderate vegetation recovery to pre-fire patterns, with regeneration to over 60% of the pre-fire levels 8-years after the fire. Regression analysis of pre- and post-fire mean NDVI exhibited significant re-growth in the first 3 years after the fire with a more gradual return in later years (an increase of 0.400 in R² by 2006 compared to only an increase of 0.129 for the subsequent 5 years). Re-growth rates appeared to be somewhat higher in north-facing slopes in comparison to south facing ones. As expected, NDVI decline due to fire was positively correlated with burn severity class, whereas negative correlation was found between damage and regeneration ability (recovery after 3 years = low severity 64%/high severity 58%, recovery after 8 years = low severity 72%/high severity 70%). To our knowledge, this study is one of the few attempting to explore the interrelationships of post-fire vegetation regrowth, topography and burn severity, especially in the case of a single large fire. RI based on control plots provides a valuable tool to quantify fire impact and subsequent vegetation regrowth. Furthermore, indication of burn severity is useful for strategically rehabilitating areas of slow or unsuitable post-fire vegetation recovery. This study corroborates the significance of EO technology as a successful and cost-effective solution in providing information related to economic and environmental post-fire regeneration assessment.     

北极地区人口数量、组成与分布

以环北极国家的北极行政区域为统计范围,利用环北极国家2001年和2006年的官方人口统计数据,对北极地区的人口状况及其演变趋势作了统计和初步分析,结果表明：（1）2006年,北极地区总人口约为1044万．人口密度为0．63人／平方公里．是地球上除南极大陆以外人口最稀少的地区：（2）在全球人口数量不断增加的情况下．北极地区近年来人口非但没有增加．而且略有减少。2006年与2001年相比．总人口减少了5．3万左右．主要原因是受俄罗斯北极区域人口减少的影响（减少了约12万）,其他国家的北极地区则呈现变化不大或略有增加的趋势：（3）北极地区地广人稀,人口分布极不均匀．主要集中在少数几个城市或城镇：北极地区首府的人口250万左右,约占总人口的24％;（4）分布在俄罗斯、北美、北欧北极地区的原住民人口约为200万．俄罗斯原住民以楚科奇-堪察加语族、阿尔泰语族、乌拉阿尔语族等北方少数民族为主,北美加拿大、美国主要以困纽特人和印第安人为主．北欧原住民则以萨米人为主。     

巴丹吉林沙漠典型湖冰冻结-消融的空间模式差异

利用多源遥感数据解译、野外考察、原位观测等方法,分析了巴丹吉林沙漠腹地湖泊群湖冰冻结-消融空间模式及其差异的主要影响因素.结果表明:该沙漠存在4种冻结-消融空间模式,湖冰自湖岸蔓延至湖心、冻结早的区域融化晚;湖冰自湖岸蔓延至湖心、冻结早的区域融化早;湖冰自湖泊一岸扩展至另一岸、冻结早的区域融化晚;湖冰自湖泊一岸扩展至另...     

Integrated,Regional, Natural Resource and Environmental Planning and the Natural Heritage Trust Phase 2: a case study of the Northern Agricultural Catchments Council,Western Australia

Since 2002, the Australian Natural Heritage Trust Phase 2 (NHT2) has required community groups seeking funds for natural resource management projects to have developed nationally accredited regional strategies and investment plans. This case study reports on the progress of one such regional (and sub-regional) group, examining in particular the perceptions of the community group members and other stakeholders of the overall process. Through interviews, participant observation and document analysis in 2004–05, the process of developing a regional strategy and an investment plan by the Northern Agricultural Catchments Council in Western Australia, and the involvement of regional stakeholders in the process, were examined. While the concept of regional-scale management was perceived favourably by community interviewees, their concerns related to increasing bureaucracy, the need for further local involvement, more on-ground action instead of further planning, the relevance of the regional Council to local communities, and the motives of Council members. Communication with regional stakeholders was extensive in preparing the regional strategy, but fell short during the development of the investment plan. The success of the regional planning process will be evidenced by whether members of the regional community actively implement regional priorities, and whether long-term funding and support from the State and Australian governments are provided.     

Fire and cyclone damage to woody vegetation on the north coast of the Northern Territory,Australia

Tree stem (>2 m tall) mortality was assessed following a late dry‐season wildfire across a seasonally flooded elevation gradient at Workshop Jungle, near Darwin, in the Northern Territory of Australia. For all species combined, dead stems had significantly smaller diameter at breast height (dbh) than living stems. Assessment of tree‐stem damage following a tropical cyclone at Cobourg Peninsula, NT, revealed that damaged stems had significantly greater dbh than undamaged stems for all tree species sampled across a boundary between monsoon rainforest and savanna. A greater proportion of stems were damaged by the cyclone than by the fire (28 per cent as against 18 per cent), although there were considerable between‐community differences in the proportion of damaged stems at the two sites. The fire caused little impact (<10 per cent) on total basal area of three different forest communities on the elevation gradient at Workshop Jungle. The cyclone was found to cause >50 per cent damage to total basal area of three different communities on Cobourg Peninsula. It is suggested that the combination of a cyclone followed by an intense fire in storm debris could potentially destroy a monsoon rainforest through its impact on all tree‐size classes. This may explain why some monsoon rainforests rapidly contracted following Cyclone Tracy that destroyed the city of Darwin on Christmas Day, 1974.     

西部含锂、钾、镁、硼盐卤资源水盐体系相化学研究

从资源特点出发 ,分别回顾了含锂、钾、镁氯化物多元水盐体系 ,镁水泥体系 ,盐卤锂、钾卤化物水盐体系的相化学研究 ,概括了主要研究成果并指出实际应用上的关键问题 ,以及研究的主要内容。     

COMPARISON OF THE ALKALI MARSH SOIL ANDAGRICULTURE SOIL ON NUTRIENT RETENTIONIN WESTERN JILIN, CHINA

An intact alkali marsh soil (MS) core and an agriculture soil (AS) core were studied by the simulated test in order to get the comparison of the nutrients retention in alkali MS and AS. The soil cores extracted from the Xiang-hai Wetland, western Jilin Province, China, were leached with solution contained carbon, nitrogen and phosphorus. Then the effluent water from the outlets of soil core with different depths was measured, including chemical oxygen demand (COD), total phosphorus (TP), phosphate (PO43-- P) and nitrogen existed as nitrate (NO3- - N), nitrite (NO2- - N) and ammonia nitrogen (NH4+- N) and the total nitrogen (TN) in the effluent water. COD and TP are decreased with the depth, the changing trends of TN, NO3- - N and NH4+ - N contents are similar to COD and TP, whereas NO2- - N in both MS and AS effluent have a little transition at 40cm depth. It is similar efficiency of MS to AS in significantly cutting down COD, TP, PO43- - P, TN, NO3- - N, NH4+ - N and NO2- - N in nutrient water. The fun     

国外休闲制约研究的特征与展望——基于《Journal of Leisure Research》、《Leisure Sciences》、《Journal of Park and Recreation Administration》期刊

选取国外三大休闲权威期刊《Journal of Leisure Research》（1992—2014年）、《Leisure Sciences》（1998—2014年）、《Journal of Park and Recreation Administration》（2001—2014年）共130篇休闲制约研究论文,通过文献统计和文献分析法,从研究方法、研究内容及发展趋势三方面,分析国外休闲制约研究的基本特征。研究认为：国外休闲制约研究方法以定量研究方法为主,定性研究方法日益受到重视;国外学者重点关注休闲制约因素、休闲制约协商、女性休闲制约、种族人群休闲制约和青少年休闲制约等内容,同时强调内在机制研究和模型构建。此外,关注社会文化制约因素,加强跨学科研究和时间纵向研究,重视中国文化背景下的休闲制约研究对世界休闲制约研究的独特贡献以及跨文化合作的必要性是未来研究的重要方向。     

中国东中西部城市土地储备决策绩效比较研究

运用数据包络分析(DEA)模型,对2013年中国内地34个大中城市土地储备决策绩效进行总体评价和比较分析。研究结果表明:东部地区城市土地储备决策效率最高,西部次之,中部最低;土地储备决策效率受到纯技术效率和规模效率的共同作用,且规模效率作用较大;影响东中西部城市土地储备决策效率投入产出的主要因素各不相同。基于此,从深化土地及相关制度改革和提升政府管理效率两个层面提出土地储备决策绩效优化策略,从而提高土地资源利用效率、优化城市空间结构。     

Holocene Vegetation History and Palaeoenvironmental Conditions on the Temperate Atlantic Coast of Argentina,as Inferred from Multi-Proxy Lacustrine Records

Holocene vegetation history and palaeoenvironmental conditions are investigated at the south coast of Buenos Aires Province, Argentina. La Olla 1 and Laguna del Sauce Grande sediment sequences are analysed for pollen, calcareous microfossil (ostracods and foraminifers) and plant macrofossil remains (mainly seeds and charophyte oospores). Supplementary information is provided by sedimentological analysis. Modern surface sample data are used to assist in the interpretation of the fossil records. La Olla 1 sequence covers the period 7890 to 7630 cal. BP. The microfauna recovered is characteristic of a shallow marginal-marine environment such as a coastal lagoon. The microfossils indicate a marine connection between 7850 and 7800 cal. BP. Plant macrofossil remains and pollen analyses indicate an extension of the water body after 7780 cal. BP. The pollen record reveals the development of a halophytic plant community in a coastal environment. The sediment record from Laguna del Sauce Grande comprises the last 3000 years. Microfossils and macrofossil remains indicate that the lake history begins with a temporary brackish-water phase. More stable conditions and higher salinity values occur between 1940 and 900 cal. BP. Periods of water level fluctuations occur after 900 cal. BP, with high water levels between 660 and 270 cal. BP. The uppermost samples of the sequence show similar conditions to present day. Pollen spectra indicate a relatively stable vegetation composition throughout the last 3000 years. Pollen assemblages reflect the present regional grassland vegetation with taxa characteristic of the surrounding dune communities.     

极端降雨事件对不同类型生物土壤结皮覆盖土壤碳释放的影响

于2011年5-8月,选择腾格里沙漠东南缘人工固沙植被区藻类、藓类和混生结皮覆盖的土壤为对象,研究了极端降雨量(降雨量44.7 mm、强度0.04 mm,min-1)、极端降雨强度(降雨量8.3 mm、强度0.55 mm·min-1)及普通降雨(降雨量16.3 mm、强度0.02 mm·min-1)条件下的碳释放过程.碳释放量的测定采用Li-6400-09土壤呼吸室,降雨结束后立即开始观测,直到呼吸速率恢复到降雨前水平时停止观测.结果表明:极端降雨(降雨量和降雨强度)结束初期藻类和混生结皮覆盖土壤的呼吸速率受到明显抑制,藻类结皮覆盖土壤呼吸速率分别为0.12 μmol·m-2·s-1和0.41 μmol·m-2·s-1,混生结皮覆盖土壤呼吸速率分别为0.10 μmol·m-2·s-1和0.45μmol·m-2·s-1;而极端降雨对藓类结皮覆盖土壤的影响不明显,呼吸速率分别为0.83 μmol·m-2·s-1和1.69μmol·m-2·s-1.这说明处于演替高级阶段的藓类结皮能够很好地应对短期的极端降雨事件.