建设甘肃河西内陆区水资源战略安全体系的构想

主要通过对河西内陆区生命支持系统的水资源战略重要性,区域社会经济的发展与问题的分析,依据现有基础条件,提出了建设甘肃河西内陆区水资源战略安全体系的构想:建立三条战略安全防线,形成四套节水技术体系,实施技术集成的示范基地建设,为实现新世纪水-经济-生态系统可持续发展提供坚实基础.     

Community participation in the management of forest reserves in the Northern Region of Ghana

The 1994 forest and wildlife policy of Ghana provides the basis for community participation in forest management through participatory forest management. Even though forest reserves in the Northern Region are said to be managed collaboratively, fringe communities are supposedly involved only in maintenance activities of the reserve boundaries and seedling planting in plantation programmes. The forest reserves are said to be threatened by illegal activities from the fringe communities. This study therefore examined the nature of community participation in the management of forest reserves.

It is a mixed method research in which structured interview schedule, in-depth interview and focus group discussion guides were used for data collection. Respondents comprised community members, forestry staff and NGOs. Communities’ participation was found to be passive and tokenistic and limited to boundary cleaning and providing labour on plantations. There is no formal collaboration between communities and Forest Services Division. Prospects to communities’ participation lie in the continuous flow of benefits and their active involvement in management decisions. Active involvement of communities in all decision-making processes, capacity building of communities and forestry staff, incentive schemes and awareness creation are recommended for promoting community participation in managing forest reserves in Northern Region.     

长江三角洲都市连绵区边界界定研究

都市连绵区的边界界定对象包括两个方面,都市连绵区的整体空间范围边界界定和内部结构边界界定。对长江三角洲及其周边地区所有的238个县、市、区的就业人口结构和空间分布特征进行主成分分析和聚类分析,探讨相应都市区的结构特征以及都市区的空间组合特征等,进而确定了长江三角洲地区的整体范围边界和内部结构边界。其结论包括①长三角都市连绵区的整体空间范围包括苏州、无锡、宁波的全部以及上海、南京、常州、杭州、镇江、扬州、泰州、南通和绍兴、舟山的部分县市区;②长三角的内部结构可分为三大部分,以上海为中心的环太湖城镇密集区,以南京为中心形成沿长江城镇区,以杭州、宁波为中心形成环杭州湾城镇密集区,其内部边界界线分别以镇江丹徒区、嘉兴—湖州为边界地带。从核心城市上海角度看,整个长江三角洲都市连绵区的内部结构呈现“圈层推进+轴线延伸”的空间特征。     

内蒙古自治区地质灾害与地质环境的关系分析

地质灾害的形成受地质环境条件中多种要素的综合控制,二者之间密切相关.这些要素包括地形地貌、气象特征、植被生态、地层岩性、地质构造、岩土体类型、人类工程活动.根据内蒙古自治区内地质灾害调查工作的研究程度及区内地质灾害的自身特点,以区内已发生灾害的大量统计数据为基础,定性分析了在何种地质环境条件下,才可能发育崩塌、滑坡、泥石流、地面塌陷灾害;定量分析了地形坡度、地形高差、沟谷流域特征、降雨量在某一具体分布范围内,才容易发育某种地质灾害;同时论述了人类工程活动对地质灾害的诱发作用.     

长江三角洲地区城市水环境承载力评估

基于压力-状态-响应(PSR)结构模型,应用环境承载力预警分析方法,分析了长江三角洲(长三角)16个城市水环境承载力演变情况,并按照压力-状态-响应的逻辑关系,提出了水环境承载力提升的建议.结果表明,2005~2010年,长三角半数城市承载力状态改善明显,包括浙江省内6个城市和江苏省内2个城市,但整体形势依然严峻,表现在2010年江苏省内6个城市和上海仍处于危机状态.此外,区域流域间承载力状况不平衡,分异性特征显著,表现在浙江省内城市显著好于江苏省内城市和上海市,太湖以南城市显著好于太湖以北和以东城市.承载力状况好坏主要与城市容量资源多寡,排污基数大小和污染减排起效快慢有关.长三角城市宜从持续减排,优化布局,提升效率的角度出发,减少承载压力,改善承载力状态,促进承载力响应.     

Incorporating geographical and evolutionary rarity into conservation prioritization

Key goals of conservation are to protect both species and the functional and genetic diversity they represent. A strictly species-based approach may underrepresent rare, threatened, or genetically distinct species and overrepresent widespread species. Although reserves are created for a number of reasons, including economic, cultural, and ecological reasons, their efficacy has been measured primarily in terms of how well species richness is protected, and it is useful to compare how well they protect other measures of diversity. We used Proteaceae species-occurrence data in the Cape Floristic Region of South Africa to illustrate differences in the spatial distribution of species and evolutionary diversity estimated from a new maximum-likelihood molecular phylogeny. We calculated species richness, phylogenetic diversity (i.e., summed phylogenetic branch lengths in a site), and a site-aggregated measure of biogeographically weighted evolutionary distinctiveness (i.e., an abundance weighted measure that captures the unique proportion of the phylogenetic tree a species represents) for sites throughout the Cape Floristic Region. Species richness and phylogenetic diversity values were highly correlated for sites in the region, but species richness was concentrated at a few sites that underrepresented the much more spatially extensive distribution of phylogenetic diversity. Biogeographically weighted evolutionary diversity produced a scheme of prioritization distinct from the other 2 metrics and highlighted southern sites as conservation priorities. In these sites, the high values of biogeographically weighted evolutionary distinctiveness were the result of a nonrandom relation between evolutionary distinctiveness and geographical rarity, where rare species also tended to have high levels of evolutionary distinctiveness. Such distinct and rare species are of particular concern, but are not captured by conservation schemes that focus on species richness or phylogenetic diversity alone.     

洞庭湖区退田还湖过程中小型兽类的生态位特征

为了解退田还湖工程实施后的小兽群落状况,2003~2010年对洞庭湖区退田还湖后9种不同类型生境中小型兽类的生态位特征进行了调查.共布放64 432夹日,捕获小型兽3 066只,总的捕获率为4.76%,包括啮齿目10种和食虫目2种.小型兽类各种群的生态位宽度以褐家鼠和黑线姬鼠最高,分别为0.819 8和0.765 6,为广生态位的种类;随后依次是臭鼩、东方田鼠、刺猬、巢鼠、黄胸鼠、小家鼠、黄毛鼠、针毛鼠,分别为0.689 0、0.573 7、0.527 3、0.482 8、0.394 8、0.289 7、0.265 1、0.098 5;社鼠和大足鼠最低,仅在1种生境中有捕获.从生态位宽度指数的季节变化看,黑线姬鼠、褐家鼠、东方田鼠和臭鼩在四季的生态位宽度指数均较高.从空间生态位宽度和生态位重叠指数看,除黑线姬鼠和褐家鼠利用生境较广外,洞庭湖小兽群落可分为3个类群:栖息于环湖丘岗林地生境的社鼠、针毛鼠和黄毛鼠类群,以湖滩生境为主的东方田鼠、巢鼠和臭鼩类群,以及以村庄周围的农田生态系统为主的家鼠类群.从生态位指标和捕获数量看,黑线姬鼠、东方田鼠和褐家鼠是当地需要重点关注的种类.东方田鼠种群数量高峰年份与低谷年份比,其生态位宽度以及与其它种类的生态位重叠指数均较高,高峰年份东方田鼠冬季在双退垸出现,说明退田还湖已扩大了东方田鼠的繁殖基地,对东方田鼠种群发展有利,在种群暴发年份,易形成更加严重的危害.     

青海湖区紫花针茅草原封育导致的土壤养分时空变化特征

封育导致的生态系统恢复会体现在土壤恢复.以不同封育年限的青海湖区紫花针茅草原为对象,研究封育导致的土壤养分时空变化特征.结果表明:同一样地速效氮、速效磷和速效钾都表现为表层含量最高,显著高于第Ⅱ层,下面几层之间差异不显著;封育对速效养分含量影响不同,对速效钾含量影响不大,而速效磷含量大多显著提高,封育样地速效氮含量稍微高于对照样地.全量养分相比较,封育对土壤全钾和全磷含量影响不大,随土层加深全氮含量降低,封育导致土壤表层全氮含量升高(提高了19.9%).有机质含量随土层加深而降低,长期封育导致土壤有机质含量增加.相关分析表明,速效钾和全钾含量之间相关不显著,速效磷和全磷、速效氮和全氮含量都表现出显著相关,有机质和全量养分之间只有全氮表现出了显著相关.封育后土壤pH值略有升高;随着土层加深,土壤容重升高,但土壤容重变化不大.封育使草原土壤养分含量增加,但是养分的增加是一个非常缓慢的过程,对草原的保护还需继续加强.     

Predicting Risk of Habitat Conversion in Native Temperate Grasslands

Abstract: Native grasslands that support diverse populations of birds are being converted to cropland at an increasing rate in the Prairie Pothole Region of North America. Although limited funding is currently available to mitigate losses, accurate predictions of probability of conversion would increase the efficiency of conservation measures. We studied conversion of native grassland to cropland in the Missouri Coteau region of North and South Dakota (U.S.A.) during 1989–2003. We estimated the probability of conversion of native grassland to cropland with satellite imagery and logistic regression models that predicted risk of conversion and by comparing the overlap between areas of high biological value and areas most vulnerable to conversion. Annualized probability of conversion was 0.004, and 36,540 ha of native grassland were converted to cropland during the period of our study. Our predictive models fit the data and correctly predicted 70% of observed conversions of grassland. Probability of conversion varied spatially and was correlated with landscape features like amount of surrounding grassland, slope, and soil productivity. Tracts of high biological value were not always at high risk of conversion. We concluded the most biologically valuable areas that are most vulnerable to conversion should be prioritized for conservation. This approach can be applied broadly to other systems and offers great utility for implementing conservation in areas with spatially variable biological value and probability of conversion.     

中国西南纵向岭谷区近百年降水的时空变化特征

对纵向岭谷地区近百年来降水的时空变化特征进行分析,结果表明:纵向岭谷区年降水量、夏季降水量和冬季降水量第一种主要分布型式呈现出一致偏多(或偏少)的特征。由于受地形阻隔、通道及地形抬升影响,岭谷地区年和夏季降水量以元江-红河流域为界,东部降水量空间分布减小,西部年降水量空间分布增加,其中心在澜沧江、怒江流域摆动,具有经向分布特征;冬季岭谷地区雨量具有纬向分布特征。近百年的降水量变化,年际变化最显著,周期变化主要集中在3.5年以下的高频振荡时域内,其次是年代际变化,最后是气候态的变化,但冬季的气候态变化并不明显;年降水分布第二模态的气候态变化是3个不同时段中最明显的,其次是夏季降水分布的第二种模态。