A protocol for classifying regional dynamics,exemplified by using woodland birds in southeastern Australia

Abstract Communities of forest and woodland birds are usually studied intensively at only one or a few locations. This provides a perspective that perhaps emphasizes local phenomena at the expense of placing local dynamics in the context of processes operating at the landscape or regional scale. The present paper seeks to redress partially this imbalance by studying the dynamics of individual bird species among several habitat types (all Eucalyptus-dominated forests or woodlands) over the annual cycle. This regional-scale (250km), continental study reveals that species exhibit idiosyncratic dynamics of various kinds: restricted or more ubiquitous occupation of habitats and three forms of seasonal dynamics at the regional scale (resident, migrant and itinerant). By using this classificatory scheme, it becomes evident that the bird communities found in different habitats consist of diverse collections of strategists and that the level of diversity differs among habitat types. The difficulties that many field workers have had in reconciling their observations with community theory most likely reflect the underlying dynamism of bird communities, especially in the temperate regions on continents where seasonal fluxes are pronounced.     

基于土地利用变化的东海区大陆海岸带生境质量时空演变研究

人类活动对生态环境的影响主要表现为土地利用方式的变化。土地利用变化影响下的生境质量时空格局演变,对优化区域国土生态布局具有重要意义。利用DEM数据、气象数据、社会经济数据与1980、1990、2000、2010、2018年5期土地利用数据,通过InVEST模型、景观格局指数、地理探测器评估、描述、分析东海区大陆海岸带生境质量时空演变特征。结果表明：(1)1980—2018年东海区大陆海岸带陆地面积增加,土地利用中林地所占比重最大,耕地、建设用地面积变化最明显,2000—2010年土地利用转化最显著。土地变化北部大于南部、东侧大于西侧。(2)1980—2018年生境质量均值为0.75,总体生境质量较好,但呈下降趋势,2000—2010年生境质量下降最明显,2010年后下降速度减缓。生境质量斑块趋于破碎化、多样化、均匀化。(3)生境质量总体上从沿海向内陆下降,受岸线性质与围垦影响,北部生境质量由陆向海退化,南部生境退化沿海向陆推进。低等生境质量区呈现点—面—带的扩张趋势。(4)建设用地指数、高程、夜间灯光亮度、土壤类型、坡度为影响生境质量分布的主要因素,38年间主导因素由高程变为建设用地指...     

Three New Species of Lagenophryid Peritrichs (Ciliophora) Ectocommensal on Freshwater Decapod Crustaceans from Madagascar1

One species of Lagenophrys and two species of Operculigera are described for the first time. Lagenophrys machaerigera n. sp. was discovered on the freshwater crab Gecarcinautes goudoti and varies between two extreme forms in the structure of its lorica aperture. Operculigera carcini n. sp. was also found on G. goudoti and exhibits several characteristics that set it apart from other members of its genus. Some of these characteristics also suggest a phylogenetic link between O. carcini and the genus Lagenophrys. Operculigera madagascarensis n. sp. was discovered on the parastacid crayfish Astacoides granulimanus. The occurrence of O. madagascarensis on a Madagascan parastacid and other species of Operculigera on Chilean parastacids suggests that parastacids are the oldest hosts of the genus Operculigera. Continental drift is the most likely mechanism by which species of Operculigera and parastacids could have been dispersed to distant parts of the southern hemisphere. The absence of Operculigera on Australian parastacids may be due to its replacement by the genus Setonophrys on those hosts.     

Première biozonation du Pléistocène Européen,principal résultat biostratigraphique de l'étude des Rhinocerotidae (Mammalia,Perissodactyla) du Miocène terminal au Pléistocène supérieur d'Europe Occidentale

For the Uppermost Miocene the already known zones MN 9 to MN 13 are used without any change; they prove to be particularly useful for the study of fossil rhinocerotids. The Plio-Villafranchian age corresponds to the zones 14 to 19, the definition of the first five being completed and the last being new. Middle to Upper Pleistocene age deals with the zones 20 to 26, all being new and defined following the same principles.     

Continental estimates of forest cover and forest cover changes in the dry ecosystems of Africa between 1990 and 2000

Aim

This study provides regional estimates of forest cover in dry African ecoregions and the changes in forest cover that occurred there between 1990 and 2000, using a systematic sample of medium‐resolution satellite imagery which was processed consistently across the continent.

Location

The study area corresponds to the dry forests and woodlands of Africa between the humid forests and the semi‐arid regions. This area covers the Sudanian and Zambezian ecoregions.

Methods

A systematic sample of 1600 Landsat satellite imagery subsets, each 20 km × 20 km in size, were analysed for two reference years: 1990 and 2000. At each sample site and for both years, dense tree cover, open tree cover, other wooded land and other vegetation cover were identified from the analysis of satellite imagery, which comprised multidate segmentation and automatic classification steps followed by visual control by national forestry experts.

Results

Land cover and land‐cover changes were estimated at continental and ecoregion scales and compared with existing pan‐continental, regional and local studies. The overall accuracy of our land‐cover maps was estimated at 87%. Between 1990 and 2000, 3.3 million hectares (Mha) of dense tree cover, 5.8 Mha of open tree cover and 8.9 Mha of other wooded land were lost, with a further 3.9 Mha degraded from dense to open tree cover. These results are substantially lower than the 34 Mha of forest loss reported in the FAO's 2010 Global Forest Resources Assessment for the same period and area.

Main conclusions

Our method generates the first consistent and robust estimates of forest cover and change in dry Africa with known statistical precision at continental and ecoregion scales. These results reduce the uncertainty regarding vegetation cover and its dynamics in these previously poorly studied ecosystems and provide crucial information for both science and environmental policies.     

Submarine Elevations and Ridges: Wild Cards in the Poker Game of UNCLOS Article 76

Submarine elevations and ridges present an array of definitional uncertainties to coastal states that are engaged in the high-stakes process of delimiting extended continental shelves. Faced with the imprecise terminology of Article 76, with the nonspecific wording of the Scientific and Technical Guidelines of the Commission on the Limits of the Continental Shelf (CLCS), and with the Commission's rules of confidentiality that hamper the open exchange of information concerning ridge and elevation assessments in previous continental shelf implementations, a coastal state needs to develop its own evaluations of what might and might not pass the “test of appurtenance.” Significant components of a continental shelf submission might thus be formulated on the basis of these national evaluations, only to have the CLCS question them, which could necessitate a potentially expensive and time-consuming reworking of the submission. This article outlines the ramifications of this wild card effect.     

Canada and Arctic Politics: The Continental Shelf Extension

This article challenges the validity of the commonly held assumption that Canada and other Arctic countries are engaged in a highly competitive scramble to stake claims for extensions to their continental shelves beyond 200 nautical miles, and that Canada may lose out because it is lagging behind in this race to claim as many seabed resources as possible. It argues that the process is orderly; that, under international law, Canada already has sovereign rights over the continental shelf beyond 200 nautical miles; that the process is generally characterized by cooperation; and that the timing of various countries’ submissions to the Commission on the Limits of the Continental Shelf will not be a key determinant of success.     

黄东海陆架区沉积物中磷的形态分布及生物可利用性

采用1992年Ruttenberg连续提取法(SEDEX)将黄东海陆架区沉积物中的磷分为交换态磷(Ex-P),Fe结合态磷(Fe-P),自生磷(Au-P),碎屑磷(De-P),有机磷(Or-P),分析了各形态磷的平面和垂直分布特征;利用沉积物年代序列测定的结果,探讨了柱状沉积物中不同形态磷的含量变化,并进一步分析了该区域磷形态的生物可利用性.结果表明,黄东海陆架区表层沉积物各形态磷平均含量为:Au-P(140.72 μg/g)＞De-P(59.23 μg/g)＞Or-P(32.69 μg/g)＞Fe-P(29.91 μg/g)＞Ex-P(5.92 μg/g);各形态磷在沉积时间序列上分布不同,反映了不同时期人类活动和气候环境等因子对磷埋藏量影响的不同,其中Au-P在长江口H1-18站位含量比南黄海中部3个站位要低得多;调查区表层潜在生物有效磷为13.55％左右,仅仅占沉积磷中的一小部分.