基于河口潮间带底栖微藻群落水平的环境质量状态评价

The feasibility of community-based bioassessment of environmental quality status was studied using microphytobenthos(MPB) in estuarine intertidal ecosystems.The sediment samples of MPB were collected monthly during a 1-year cycle(September 2006–August 2007) at four sampling stations in the Nakdong River Estuary,Korea.Environmental variables,such as salinity,radiation,grain size of sediment,Si(OH)_4(Si),nitrate(NO_3~–),nitrite(NO_2~–),ammonium(NH_4~+) and phosphates(PO_4~(3–)),were measured synchronously for comparison with biotic parameters.The statistical analyses were carried out for assessment the relationship between biotic and environmental parameters.The results showed that:(1) the MPB community structures were significant differences among four sampling stations;(2) spatial variation in the MPB communities were significantly correlated with environmental variables,especially the nutrient NH_4+ in combination with salinity and grain size;(3) three species(Navicula lacustris,Pleurosigma anglulatum and Fragilaria sp.1) were significantly correlated with nutrients and/or Si;and(4) the species richness and diversity were significantly correlated with the grain size.It is suggested that MPB communities may be used as a potentially robust bioindicator for assessing environmental quality status in estuarine intertidal ecosystems.     

极地产甲烷菌研究进展

产甲烷菌是一类重要的环境微生物,其代谢产生的甲烷(CH_4)是最重要的温室气体之一。现有研究表明,产甲烷菌广泛存在于极地湿地、沼泽、湖泊、苔原、冻土和冰川等各类生境之中,并在碳循环中发挥着重要作用。本文对极地产甲烷菌的群落结构、生物多样性、空间分布、环境影响因子(温度﹑营养物和pH)以及研究技术的最新进展进行了总结,并对极地产甲烷菌研究的未来发展进行了展望。     

Urban Community Garden Agrodiversity and Cultural Identity in Philadelphia,Pennsylvania, U.S.

Considerable research has examined the social, cultural, economic, and community benefits of urban gardening. Few studies, however, have empirically assessed factors that influence urban community garden agrodiversity or its relationship to these dimensions of gardening. We conducted an interdisciplinary study of agrodiversity and cultural identity, based certain markers of identity, including how people see themselves with respect to race, ethnicity, or place of origin, in community gardens in Philadelphia, Pennsylvania. We conducted fifty‐six semistructured interviews with gardeners with different cultural identities in eight community gardens on their motivations for urban community gardening during 2014. We conducted plant inventories of the corresponding garden plots and found 104 cultivated edible and ornamental species and 28 varieties representing 34 families. We find that although gardens with culturally diverse gardeners did not have higher species richness, the cultural identity of the gardeners influenced species selection and reason for gardening. Further, the structure, design and species composition of garden plots reflected the identities of garden members. These finding have implications for the recent institutionalization of urban agriculture into city land policies in Philadelphia and other cities in North America.     

Climate‐induced migration: Exploring local perspectives in Kiribati

A number of studies have indicated that the long term habitability of Kiribati, a low‐lying country in the central tropical Pacific Ocean, is tenuous given the impacts of climate change, particularly sea level rise. In an effort to plan for the resultant challenges ahead, a number of national policies and programs have surfaced to reduce the impact of localized changes on people's livelihoods. This study explores how local community members (n = 60) have taken it upon themselves to respond to the impacts of climate change by utilizing a number of different strategies. The results highlight that: first, respondents consider climate change to be the most concerning issue for sustaining their livelihoods; second, respondents have built physical defences, relocated temporarily or permanently, and sought government assistance to adapt to localized climate‐related impacts; and third, the majority of respondents indicated that they would migrate as a long term strategy to respond to the future impacts of climate change.     

Inserting scales of urban politics: the possibilities of meso-urban governance shims

This article explores the geographic literature on governance at smaller-than-urban but larger-than-household scales, identifying a relative inattention to neighborhood and other partial-city scales of governance. Hegemonic power relationships are institutionalized at particular scales of state government (e.g. national, regional, municipal) and state-sanctioned governing units (e.g. jurisdictional districts or supranational bodies), which in turn shapes urban research. We propose a new analytical term, governance shims, to describe the insertion of new scales of governance between those already reified and reproduced; institutions at such scales may be unusually grounded in authority beyond the state. Geographers seem well positioned to explore the characteristics of governance shims at the meso-urban scale. We illustrate this by briefly tracing how common interest communities (CICs), housing cooperatives, and community land trusts (CLTs) might be analyzed through a shims approach. Provocatively, emergent governance at the meso-urban scale often leverages idiosyncratic structures of property ownership to produce institutional authority.     

Legacies of a Contested Campus: Urban Renewal,Community Resistance,and the Origins of Gentrification in Denver

The postwar urban renewal experience varied among US cities according to the result of local social contests pitting those imposing their power to transform urban space against those resisting it. In this paper, we examine the role of one such contest in shaping urban renewal outcomes in Denver, using the case of the late 1960s Auraria project. The project sought to remove a poor, Hispanic neighborhood in order to build a new downtown college campus, generating community opposition from the inner city neighborhood residents, leaders of the city’s Chicano Movement, and historic preservation activists. We demonstrate how resistance actively shaped the ultimate form and character of the project, and how the legacies of this urban renewal contest extended—in unforeseen ways—beyond the immediate struggles of the time. We argue that these legacies provide the essential context for understanding planning practice, redevelopment strategies, and gentrification dynamics in the city today.     

基于公路客流的中国城市网络结构与空间组织模式

多视角和多尺度城市网络逐渐成为认识空间关系的主要途径。公路流数据具有显著的空间依赖性和距离衰减特性,对于刻画区域尺度空间关系具有重要意义。基于全国地级行政单元间的公路客运流,论文尝试刻画中国城市网络功能结构和区域效应,并对其空间组织模式进行特征提取和规律挖掘,以期能够为城市网络研究提供新的方法支撑和认知视角。研究结果表明：① 基于公路流的城市网络空间形态表现出强烈的空间依赖性和层级特征,与中国主要城市群分布存在较大程度的空间耦合,更多体现的是区域尺度的空间关系及核心—外围组合关系;② 通过社区发现算法识别出19个城市经济区,其空间内涵主要包括行政区经济、巨型区域溢出效应和核心—边缘结构等;③ 不同地域系统内城市网络自成体系,表现出显著的空间依赖性和多元的空间组织模式,多层次、流动性和网络化的地域系统格局凸显;④ 从空间形态上看,区域城市网络空间结构大致可划分为单中心结构、双核心结构、多中心结构和低水平均势结构等区域关联形态,并以单中心发育模式为主。     

社区环境对入室盗窃和室外盗窃影响的对比分析——以ZG市ZH半岛为例

社区环境的基本属性是影响城市犯罪的重要因素,而这两类犯罪相似的空间形态受社区环境哪些因素的影响及作用方式如何未探寻及验证。因此,本文结合日常活动理论、CPTED理论、可防卫空间等理论,以中国东南沿海地区ZG市ZH半岛为例,融合多源异构时空数据,利用偏最小二乘法,检验社区尺度下的建成环境和社会环境,对入室盗窃和室外盗窃的影响进行对比分析。研究发现：① ZH半岛内具有一定的规律性特征,即在建成环境背景下,入室盗窃的影响因素相对集中,而室外盗窃的影响因素较为分散;② 社会环境和建成环境对两类犯罪的影响及作用力存在着相对的共性和差异性,其共性主要表现在人口密度（-）、青少年人口比重（+）、公交站点密度（-）以及到主中心的距离（-）对入室盗窃和室外盗窃的发生都有显著的影响,且作用力方向一致;差异性主要体现在道路网络密度（-）、零售商业密度（+）和餐饮住宿密度（+）是影响室外盗窃发生的主要因子,而居民文化程度（-）显著影响入室盗窃的发生。研究结果的引申,可为社区层面的入室盗窃和室外盗窃的联合防控提供一些参考。