喀斯特区天然林不同演替阶段功能性状特征及其影响因素研究 ——以云南大黑山为例

不同演替阶段群落的环境条件有所不同,变化的环境因子驱使群落水平上功能性状和物种适应环境的生态对策改变,然而次生演替过程中群落功能性状和物种生态对策随演替时间的变化规律尚不清楚.本文以云南大黑山喀斯特地区弃耕后处于不同恢复阶段的天然次生林(3年,6年,20年,40年)和老龄林为研究对象,结合不同群落演替阶段的物种特征和群...     

Hydrologic Variability and Its Control of Phytoplankton Community Structure and Function in Two Shallow,Coastal, Lagoonal Ecosystems: The Neuse and New River Estuaries,North Carolina,USA

Hydrologic conditions, especially changes in freshwater input, play an important, and at times dominant, role in determining the structure and function of phytoplankton communities and resultant water quality of estuaries. This is particularly true for microtidal, shallow water, lagoonal estuaries, where water flushing and residence times show large variations in response to changes in freshwater inputs. In coastal North Carolina, there has been an increase in frequency and intensity of extreme climatic (hydrologic) events over the past 15 years, including eight hurricanes, six tropical storms, and several record droughts; these events are forecast to continue in the foreseeable future. Each of the past storms exhibited unique hydrologic and nutrient loading scenarios for two representative and proximate coastal plain lagoonal estuaries, the Neuse and New River estuaries. In this synthesis, we used a 13-year (1998–2011) data set from the Neuse River Estuary, and more recent 4-year (2007–2011) data set from the nearby New River Estuary to examine the effects of these hydrologic events on phytoplankton community biomass and composition. We focused on the ability of specific taxonomic groups to optimize growth under hydrologically variable conditions, including seasonal wet/dry periods, episodic storms, and droughts. Changes in phytoplankton community composition and biomass were strongly modulated by the amounts, duration, and seasonality of freshwater discharge. In both estuaries, phytoplankton total and specific taxonomic group biomass exhibited a distinctive unimodal response to varying flushing rates resulting from both event-scale (i.e., major storms, hurricanes) and more chronic seasonal changes in freshwater input. However, unlike the net negative growth seen at long flushing times for nano-/microphytoplankton, the pigments specific to picophytoplankton (zeaxanthin) still showed positive net growth due to their competitive advantage under nutrient-limited conditions. Along with considerations of seasonality (temperature regimes), these relationships can be used to predict relative changes in phytoplankton community composition in response to hydrologic events and changes therein. Freshwater inputs and droughts, while not manageable in the short term, must be incorporated in water quality management strategies for these and other estuarine and coastal ecosystems faced with increasing frequencies and intensities of tropical cyclones, flooding, and droughts.     

Paleoecology of Early Ordovician Reefs in the Yichang Area, Hubei: a Correlation of Organic Reefs Between Early Ordovician and Jurassic

The Early Ordovician System is composed mainly of a series of carbonate platform deposits interbedded with shale and is especially characterized by a large number of organic reefs or buildups that occur widely in the research area. The reefs have different thicknesses ranging from 0.5 m to 11.5 m and lengths varying from 1 m to 130 m. The reef-building organisms include Archaeoscyphia, Recepthaculitids, Batostoma, Cyanobacteria and Pulchrilamina. Through the research of characteristics of the reef-bearing strata of the Early Ordovician in the Yichang area, four sorts of biofacies are recognized, which are (1) shelly biofacies: containing Tritoechia-Pelmatozans community and Tritoechia-Pomatotrema community; (2) reef biofacies: including the Batostoma, Calathium-Archaeoscyphia, Pelmatozoa-Batostoma, Archeoscyphia and Calathium-Cyanobacteria communities; (3) standing-water biofacies: including the Acanthograptus-Dendrogptus and Yichangopora communities; and (4) allochthonous biofacies: containing Nanorthis-Psilocephlina taphocoense community. The analysis of sea-level changes indicates that there are four cycles of sea-level changes during the period when reef-bearing strata were formed in this area, and the development of reefs is obviously controlled by the velocity of sea-level changes and the growth of accommodation space. The authors hold that reefs were mostly formed in the high sea level periods. Because of the development of several subordinate cycles during the sea-level rising, the reefs are characterized by great quantity, wide distribution, thin thickness and small scale, which are similar to that of Juassic reefs in northern Tibet. The research on the evolution of communities shows that succession and replacement are the main forms. The former is favorable to the development of reefs and the latter indicates the disappearance of reefs.     

黔南扁平村晚石炭世生物礁生物群落分析

在黔南紫云猴场镇以西约4 km扁平村发现了新的大型生物礁组合。该礁产于马平组Triticites带内,时间上隶属于晚石炭世晚期。通过对该礁组合中生物群落的详细研究,将其自下而上划分为组合面貌不同的6个群落。其中成礁生物群落有两个：珊Ivanoviacfmanchurica,叶状藻Eugonophyllum和菌藻类蓝细菌群落及珊瑚Formitchevella群落。前者各种生物在不同环境中独立发育构成小点礁,彼此平行排列,形成下部点礁层;后者由大型笙柱状排列的Formitchevella构成其上部主礁体。这些群落代表了生物礁的不同发展阶段,显示了在造礁过程中生物种类更替演化的特征,而群落演化与成礁有一致的对应关系,并控制着该生物礁的发育和规模。以特征生物Formitchevella为代表的造礁群落的组成、结构、生态特征和礁体生长发育模式在中国乃至世界上的石炭纪礁体中都是独特的,构成了晚石炭世罕见的非藻造架生物礁。扁平村生物礁的发现,丰富了世界石炭纪造礁生物群落的类型,为研究石炭纪造礁生物群落演化、礁体生长及建立生物礁生长动力学模型提供了新的实例。     

塔里木盆地面西部白垩纪—古新世有孔虫群落的划分及其环境意义

有孔虫是塔里木盆地西部海相白垩系－古新统的最重要化石门类之一，可划分为９个群落。西文依据有孔虫壳质类型变化规律，有孔虫壳壁微量元素和群烽理统计探讨有孔虫群落有其生存环境的关系，特别是与温度和盐度的关系，重塑这一时期古海洋环境演变。     

Ethnic enterprises and community development

Ethnic enterprises are growing rapidly in urban areas across the United States. Anecdotal evidence from around the country reports many success stories of how ethnic businesses transform communities; however, researchers have not provided a systematic review of the role of ethnic businesses in community developing. In practice, ethnic businesses have not been formally incorporated in local planning and development process. This article provides a systematic review of the multi-faceted ways ethnic businesses contribute to community building and neighborhood development. In addition to surveying the current literature, we also chose three communities for a focused review: Buford Highway in Atlanta, Monterey Park in Los Angeles, and Sunset Park in New York. A framework is developed to evaluate the economic, physical, social/cultural, and political effects that ethnic businesses exert on communities. We find that ethnic businesses can serve local economic interests and community-level cohesion and accrue economic, social, physical, and political benefits to their respective communities. These include serving the unmet market needs of certain neighborhoods and households, creating job opportunities and generating revenues, revitalizing and fueling the commercial development of abandoned communities, organizing and promoting social life and cultural diversity, as well as contributing their collective interest and voice in local communities. We argue that ethnic businesses should be better incorporated into urban policies in community economic development.     

Organic functionalism, `community' and place: refugee studies and the geographical constitution of refugee identities

The growth in the global population of refugees over the last 20 years has been paralleled by the development and growth of refugee studies as a recognised discipline. However refugees do not comprise a naturally self-delimiting domain of scientific knowledge and have been constituted by refugee studies through discourses that emphasise humanitarian, apolitical and organic functionalist discourses that root refugee identities in particular places. This paper argues that the presently inadequate constitution of refugee identities in refugee studies has been compounded by geographic representations of regional refugee emergencies, stable conceptions of refugees and asylum seekers and dated and unproblematic understandings of space as inactive and not constitutive of social life. Using data collected in interviews held between 1995 and 1998 with representatives from refugee and asylum institutions and organisations this paper illustrates how discourses and funding policies that unproblematically assume community groups represent refugees asylum seekers ignore transnational differences and tensions that can exist in marginalised communities. However it should be pointed out that the discourses about place, nationality and identity and `natural' communities can also be used by the powerless to resist their marginalised and excluded positions.     

Community resilience to tsunamis along the Southeastern Pacific: a multivariate approach incorporating physical,environmental, and social indicators

Tsunamic events are a frequent hazard to coastal towns. Despite this, the extent to which resilience models can be applied to coastal towns as well as the aspects that should be considered when doing so have not been fully evaluated. There is little information regarding the specific indicators that allow cities to better cope and adapt to the impacts of tsunamis, and this information is especially scarce for developing countries such as Chile. The main objective of this study is to develop a resilience model to explore the extent to which local characteristics influence the resilience of Chilean coastal communities to tsunami hazards. Accordingly, this study presents the Coastal Community Resilience model (The CORE model) for exploring the adaptive capacity of coastal areas affected by tsunamis. This model was then applied to fourteen coastal villages, distributed within four towns, three communes, and two regions of Chile. Data comprising 21 indicators that address the physical, environmental, and social resilience aspects of the villages were obtained on-site and from governmental and municipality databases; these data were then subjected to multivariate analysis in order to determine which indicators most and least affect resilience and whether indicators affect resilience positively or negatively. Variation in resilience among the villages was explained by similarities and differences in the administrative-political, urban, rural, and indigenous characteristics of the study areas. In addition to these results, we discuss land use planning considerations to build community resilience, and we provide insight into the utility of the resilience model proposed here. Overall, our findings shed light on gaps in planning policies and opportunities for planning coastal resilient communities, particularly for those where data of explicit indicators are scarce like in Chile and other developing countries.

     

藏北安多东巧地区晚侏罗世生物礁古生态学研究

安多东巧地区上侏罗统沙木罗组主要为一套潮坪相碎屑及台地相碳酸盐沉积,其中的特征沉积是发育有生物礁。造礁生物主要为层孔虫,其次为珊瑚,其中,层孔虫又可以分为筒状、块状和枝状3种宏观形态。在对造礁生物的个体生态学分析基础上,根据其组合特征,将生物礁划分为3个造礁群落,分别是Milleporidium—Cladocorops...     

Placing voluntarism within evolving spaces of care in ageing rural communities

Guided by a theorisation of voluntarism as a critical process shaping local outcomes of changes underway in health care systems and in rural communities, this paper re-analyses qualitative results from previous case studies of rural ageing to deconstruct the multifaceted role of the voluntary sector in facilitating the emergence of homes and communities as ‘new’ spaces of care. The specific focus is on the lived experience of voluntary sector care providers from the perspectives of non-profit organisations, community groups and families as well as elderly residents of rural communities in Canada and New Zealand. The findings confirm the local dynamics of voluntarism as a crucial yet neglected component of sustainable rural services and communities. More importantly, they reveal the voluntary sector as a major source of resistance to both the short-term changes mandated by restructuring and longer-term changes associated with rural ageing and service decline. It is through resistance that voluntary organisations and volunteers are seen to be engaging most intensely with the challenge of ageing in place within evolving spaces of care. A more nuanced understanding of their complex role is a prerequisite for developing informed policy on rural ageing and care provisioning.     

Windfalls for whom? The evolving notion of ‘community’ in community benefit provisions from wind farms

This paper investigates the increasing provision of ‘community benefits’ – i.e. financial or material benefits to communities affected by wind energy development – with a focus on on-shore wind projects in Wales. The paper argues that as community benefits are becoming more significant in scale, so pressures are mounting on what have hitherto been largely ad hoc arrangements for their disbursement. The paper finds that previously dominant definitions of communities as places directly affected by and within close proximity to wind farm development, are being challenged by the tendency to define ‘affected’ communities as broader entities characterised by more indirect and widely dispersed claims to benefit entitlement. This redefinition of the recipient community is causing conflict, much of it focused on debates about how community benefits should be governed. Evidence suggests that any re-scaling of relations around community benefits – from local compensation towards wider development goals – may be more consensually achieved in communities with previous experience in handling these funds, and where growing income streams allow multiple constituencies to be satisfied.     

Vegetation Dynamics in a Tidal Freshwater Wetland: A Long-Term Study at Differing Scales

Tidal freshwater wetlands are complex, species-rich ecosystems located at the interface between tidal estuaries and nontidal rivers. This study conducted on the Patuxent River estuary in Maryland was designed to assess vegetation dynamics over several decades to determine if there were directional changes in the dominant communities. Aerial photographs (1970, 1989, and 2007) documented broad-scale spatial changes in major plant communities. The coverage of areas dominated by Nuphar lutea and Phragmites australis expanded; mixed vegetation and scrub–shrub habitats were essentially unchanged; and Typha and Zizania aquatica communities fluctuated in coverage. Data collected between 1988 and 2010 from permanent plots and transects were used to examine fine-scale changes. Shifts in the importance of some species through time were observed, but there were no directional changes in community species composition. The lack of directional change as measured at a fine scale is characteristic of tidal freshwater wetlands in which variations in the abundance of individual species, especially annuals, are responsible for most short-term change in species composition. Changes in the composition of plant communities are interpreted as responses to variations in vertical accretion, stability of habitat types, invasive plant species, and herbivores. In the future, vegetation changes are likely to occur as a result of the intrusion of brackish water and increased flooding associated with global climate change and sea level rise. This long-term study establishes a baseline from which potential future changes to tidal freshwater wetlands can be better understood.     

Land, ethnic, and gender change: Transnational migration and its effects on Guatemalan lives and landscapes

Migration to the United States of America from Guatemala effects many aspects of Guatemalan life. We document, through extensive ethnographic fieldwork, how migrants and their remittances effect gender relations, ethnicity, land use, and land distribution. Our evidence is drawn from research in four communities. San Pedro Pinula and Gualán represent communities of eastern Guatemala. San Cristóbal Totonicapán is an Indigenous town in Guatemala’s western highlands, and San Lucas is a lowland frontier community in the Guatemalan department of Ixcán, which borders Chiapas, Mexico. Our results reveal that migrants and their remittances, both social and tangible, result in significant changes in land use and land distribution in Ixcán. Migrant money permits the conversion of rainforest into cattle pasture and also results in the accumulation of land in the hands of migrants. In terms of land use, we see in San Pedro Pinula that migrant money also allows the Pokoman Maya to make small entries into the Ladino (non-indigenous) dominated cattle business. In San Pedro Pinula, the migration and return of Maya residents also permits them to slowly challenge ethnic roles that have developed over the last five centuries. When we look at how migration effects gender roles in Gualán and San Cristóbal we also note that migration and social remittances permit a gradual challenge and erosion of traditional gender roles in Guatemala. We point out, however, that migration-related changes to traditional gender and ethnic roles is gradual because migrants, despite their increased earnings and awareness, run into a social structure that resists rapid change. This is not the case when we examine land transformations in Ixcán. Here, migrants encounter few barriers when they attempt to put their new money and ideas to work. Despite the advantages that migration brings to many families, especially in the face of a faltering national economy and state inactivity regarding national development, we conclude that migration and remittances do not result in community or nation-wide development. At this stage migrant remittances are used for personal advancement and very little money and effort is invested in works that benefit communities or neighborhoods. We call for continued studies of the effects of international migration on Guatemalan hometowns that build on our initial studies to better understand the longer-term ramifications of migration in a country where no community is without migrants.     

陕西秦岭海槽晚石炭世三里峡生物礁群落相研究

通过对发育于陕西秦岭海槽晚石炭世三里峡生物礁的生长过程、古生态特征及其造礁作用的研究，鉴定出６个门类的２３个属，主要为有孔虫、藻类、腕足类及介形类等。它们组成２个造礁群落，并形成独立的群落结构。该生物礁的造礁功能比较复杂，在礁的不同生长阶段有不同的造礁作用方式，具有以一种造礁作用为主兼有多种造礁作用共同作用的特点。其生长可分为生物定殖、障积式造礁及包粘式造礁三个阶段     

广西弄岗喀斯特区域不同群落的稳定性评价分析

选取群落本地种盖度和多样性等5个方面共9项具有表征群落稳定特性的主要指标构成指标体系,运用主成分分析法和灰色关联度分析法,综合评价分析了广西弄岗喀斯特区域群落稳定性;并根据稳定性分级公式将群落划分为强、中、差三个等级。结果表明:肥牛树(Cephalomappa sinensis)+秋枫(Bischofia polycarpa)-网脉核实(Drypetes perreticulata)-高脚沿阶草(Ophiopogon dracaenoides)等群落的稳定度指数较大。飞机草(Eupatorium odoratum)+三叶葛藤(Pueraria phaseoloides)等群落的稳定度指数较小。肥牛树+秋枫-网脉核实-高脚沿阶草等8个群落为强稳定性级别群落,苦楝(Melia azedarach)+任豆(Zenia insignis)-野桐(Mallotus japonicus)-蔓生莠竹(Microstegium fasoiculatum)+飞机草等4个群落为中等稳定性级别群落,飞机草+三叶葛藤群落、红花三宝木(Trigonostemon lutescens)+潺槁树(Iitsea glutinosa)-飞机草等14个群落为差稳定性级别群落。植被的稳定性大小顺序(原生性天然林>次生天然林>灌丛/人工林>草丛),反映了演替稳定性规律,即群落稳定性随着演替的进行而增高。      

Distribution characteristics and factors influencing microbial communities in the core soils of a seawater intrusion area in Longkou City,China

Microbes live throughout the soil profile. Microbial communities in subsurface horizons are impacted by a saltwater–freshwater transition zone formed by seawater intrusion (SWI) in coastal regions. The main purpose of this study is to explore the changes in microbial communities within the soil profile because of SWI. The study characterizes the depth-dependent distributions of bacterial and archaeal communities through high-throughput sequencing of 16S rRNA gene amplicons by collecting surface soil and deep core samples at nine soil depths in Longkou City, China. The results showed that although microbial communities were considerably impacted by SWI in both horizontal and vertical domains, the extent of these effects was variable. The soil depth strongly influenced the microbial communities, and the microbial diversity and community structure were significantly different (p < 0.05) at various depths. Compared with SWI, soil depth was a greater influencing factor for microbial diversity and community structure. Furthermore, soil microbial community structure was closely related to the environmental conditions, among which the most significant environmental factors were soil depth, pH, organic carbon, and total nitrogen.

     

Community resilience,globalization, and transitional pathways of decision-making

This article investigates the impacts of globalization processes on community resilience. It argues that theoretical concepts such as transition theory can provide a lens through which resilience pathways at community level can be better understood, and proposes a framework focused on a social resilience approach for understanding community resilience as the conceptual space at the intersection between economic, social and environmental capital. It argues that certain types of communities are losing resilience through increased embeddedness into globalized pathways of decision-making, while other communities may be gaining resilience, although not one system is either totally resilient or totally vulnerable. Striking the right ‘balance’ between communities and their scalar interactions with the global level is key for maximization of community resilience: while too much isolation of a community may be bad in light of over-dependency on local resources, skills and people, ‘over-globalization’, with possible loss of autonomy and identity, may be equally fraught with problems. In particular, relocalized communities have, so far, not shown much tangible success, as almost all members of the relocalization process at community level are simultaneously embedded within the global capitalist system through their dependencies on global economic processes.     

深海洋底热泉生态系和冷泉生物研究综述

现代海洋学、微生物学和生物学的研究表明，在深海火山活动和板块消减带所形成的地质背景下分别可能有海底热泉和冷泉的存在。在这种海底热泉和冷泉区的特殊环境中能够能海底热泉生态系的冷泉生物。它们能够依靠体内共生化学厌氧合成细菌产生营养，因而可能存在于完全缺氧的还原环境。海底热泉和冷泉生物学研究是对传统的生物学和地质学的挑战，人们还可能通过古代海底热泉和冷泉生态系的识别和分析，对涉及生命发生、生物演化、生物     

Seasonal Variation in Nekton Assemblages in Tidal and Nontidal Tributaries in a Barrier Island Lagoon System

Fish communities in tidal tributaries have received considerable attention, but the relative value of nontidal tributaries (having a tidal amplitude of <?5 cm) may represent an under-valued habitat. A multi-gear sampling approach was used to collect fish and macroinvertebrates from one tidal and two nontidal tributaries to describe and compare the respective nekton communities and habitat use patterns. Nekton communities in tidal and nontidal tributaries were markedly different even though habitats were similar (e.g., temperature, DO, depths, shoreline vegetation). While catch-per-unit-effort (CPUE) of estuarine-dependent species (e.g., red drum, spot, common snook) was lower in nontidal tributaries, the overall nekton CPUE was twice that of the tidal tributary, and the community was comprised mostly of freshwater marsh species (e.g., eastern mosquitofish, sailfin molly, bluefin killifish). Based on the life histories of the fishes that differed between tributary types, the proximity of coastal inlets and availability of effective larval transport mechanisms for estuarine-dependent species may be greater determinants of community differences than factors related to tributary size or shoreline habitat type. These results recognize smaller nontidal tributaries as undervalued nursery habitats and suggest the function as secondary nursery habitats is a critical service to the overall estuarine community.     

Gated community and residential segregation in urban China

Research on gated community in Chinese cities has been growing very fast, but empirical studies are limited, especially those on the relationship between gated community and residential segregation. A retrospective questionnaire survey was conducted in three gated communities in Chongqing, China. The findings from the survey include that, after moving into the gated communities, many homeowners’ contact with other people decreases. It is also found that homeowners’ participation in local public affairs decreases. These results hold even when we compare with the reference group and control for duration of stay. They support the view that gated community aggravates residential segregation. However, the survey shows that many homeowners feel the income differences among the neighbors increase and the changes of several types of external activities don’t show a consistent pattern. All these empirical findings suggest that a complex relationship between gated community and residential segregation exists in urban China and the removal of work unit from the housing system affects people’s experience in gated community.