Connecting local environmental knowledge and land use practices: A human ecosystem approach to urbanization in West Georgia

Issues of urban sprawl and migration of exurban residents into the surrounding countryside of metropolitan areas have generated considerable debate across the US. These debates often revolve around the ecological footprint of urban areas and the erosion of quality of life indicators associated with rapid expansion of urban and residential areas. Although there has been much research done on the environmental and socioeconomic impacts of urbanization, little attention has been given to cultural impacts. This paper focuses specifically on the role of local environmental knowledge as an important resource in human ecosystems, and looks at the implications of environmental knowledge loss associated with urbanization and its related demographic changes. We compared environmental knowledge among rural, urban, and developing watersheds in western Georgia, and also look at relationships between local environmental knowledge and variables such as gender, education, income, and participation in outdoor recreational activities. We then explored how variations in environmental knowledge affected land use practices at the household level. The mean knowledge scores of residents in all three classifications of rural watersheds were higher than those living in developing and urban watersheds. We found residents of managed pine watersheds possessed the highest mean scores (p = 0.006), while urban watershed residents were the lowest. We also found that local environmental knowledge was influenced by active participation in outdoor recreation, with active bird-watchers having the highest environmental knowledge scores. However, we found less influence of factors such as education and income on environmental knowledge. We also found a clear connection between local environmental knowledge and land management practices. Timber owners scored higher than non-timber owners (p = 0.099), and landowners who constructed streamside management zones (SMZs) scored higher than those who did not (p = 0.034).     

Detection of biotic responses to urbanization using fish assemblages from small streams of western Georgia,USA

We examined relationships between stream fish assemblages and land use alteration associated with urbanization in 15 lower Piedmont watersheds along an urbanization gradient north of Columbus, western Georgia. Based on land cover data from 2002 Landsat 7 TM imagery aerial photos, streams drained watersheds that were largely urban, developing (suburban), agricultural (pasture), managed pine forest, and unmanaged mixed-forest. We quantified fish seasonally from 3 run-pool segments in each stream, and used a variety of metrics as response variables in analyses of relationships between fish assemblage structure and land use and natural basin variation. In general, Georgia-Index of Biotic Integrity (GA-IBI) values, Bray-Curtis faunal similarity of streams to mean conditions within reference streams, proportions of fish as lithophilic spawners, and fish lacking eroded fins, lesions, tumors decreased with increasing urbanization. Multiple regression indicated that assemblages were explained by a combination of land use and natural basin variables (basin size, average discharge, nearest distance to a larger downstream tributary [colonization source]), with land use variables being important predictors of summer assemblages and natural basin variables being more important in winter and spring assemblages. Non-metric multidimensional scaling (NMDS) ordinations revealed strong separation between assemblages in urban watersheds and forested watersheds, whereas assemblages in agricultural and developing watersheds were intermediate between those in urban and forested watersheds. Our data suggest that fish are reliable indicators of anthropogenic disturbance at the landscape scale, at least seasonally, and may be used to forecast the magnitude of landscape-level changes in stream structure and function associated with the conversion of forests to urban/suburban land in the Southeast.     

Butterflies in the city: a review of urban diurnal Lepidoptera

Human migration to urban centers has resulted in diverse environmental disturbances that affect biodiversity. Although urbanization has been highlighted as one of the main drivers of biodiversity endangerment, this topic is still poorly studied in many countries. In order to establish the status quo of the ecology of butterflies in urban centers, we gathered publications focused on urban butterflies (Lepidoptera). We compiled a total of 173 studies from 37 countries and more than 110 urban areas, including published papers and theses (1956–2015). Most papers (69 %) addressed ecological topics, 14 % were focused on biological conservation, and 17 % corresponded to species lists. In summary, most studies revealed a negative impact of urbanization intensity on butterfly diversity (richness and abundance). In fact, we found studies reporting local extinctions due to urbanization, highlighting the causes related to them. The study of charismatic urban wildlife groups, such as butterflies, is a promising field, as there are still important gaps in our comprehension of the ecological patterns and processes that occur in urban areas. Undoubtedly, understanding the response of butterflies to urbanization will aid in the development of urban biodiversity management, planning, and conservation strategies worldwide, which together with knowledge of other wildlife groups and socioeconomic variables, will lead us to more sustainable, livable, and biodiverse cities.     

Effect of urbanization on surface water chemistry in south-central Texas

The use of state factors can adequately describe the biogeochemistry and geochemistry of relatively undisturbed surface waters. Watersheds with increasing proportions of urban and suburban land use, particularly in sub-tropical, semi-arid and arid urban areas, that utilize irrigation for turfgrass and landscaping may have a low flow urban signature that relates to the source water used by municipal water suppliers. We examined thirteen watersheds; four with waste water treatment plants (24–67% urbanization), four rural (< 30% urbanization) and five urban (> 30% urbanization) in a humid sub-tropical oak savannah in south-central Texas. Three of our urban and one of our rural watersheds displayed the signature of municipal tap water. Three out of four watersheds with waste water treatment plants displayed the signature of treated sewage effluent. We suggest as a result of this study that the chemistry of municipal tap water particularly that with high sodium and bicarbonate, used in urban watersheds for irrigating turfgrass and landscapes may have detrimental effects on base flow stream water quality after it has interacted with watershed soils.     

Comparison of decapod communities across an urban-forest land use gradient in Puerto Rican streams

Urbanization influences a range of factors related to stream health, including the hydrologic regime, water quality, and riparian conditions that lead to negative effects on terrestrial and aquatic ecosystems. However, impacts on freshwater decapods from urbanization of tropical streams have not been reported. We hypothesized that changes in decapod communities in watersheds with different levels of urbanization are related to changes in physical stream habitats caused by different land uses and their effects on water discharge. The impacts of land use on the physico-chemical characteristics of streams and freshwater decapod communities were evaluated in three watersheds characterized by low, moderate and high-intensities of urbanization in Puerto Rico. For the low and moderately developed urban watersheds, decapod species richness ranged from 10 to 11 species; the highly urbanized watershed only had 4 species. Macrobrachium faustinum and Xiphocaris elongata were the most ubiquitously species and were found in all watersheds. Multivariable analysis of physical characteristics and densities of the decapod families resulted in one axis that explained 80 % of the total variation among the watersheds and was correlated with stream discharge. The effect of discharge is likely a result of frequent high flows that sustain habitats with high concentrations of dissolved oxygen and low concentrations of pollutants. An increase in physico-chemical parameters were observed from the LUW to the HUW. These results indicate that the decapod communities were most likely influenced by land use and environmental conditions that affected erosional aspects related to water discharge and water quality in the highly impacted watersheds.     

Changes in chemical and physical propertiesof stream water across an urban-rural gradient in western Georgia

The Middle Chattahoochee River Watershed in western Georgia is undergoing rapid urban development. Consequently, Georgia’s water quality is threatened by extensive development as well as other land uses such as grazing. Maintenance of stream water quality, as land development occurs, is critical for the protection of drinking water, biotic integrity, and stream morphology. A two-phase, watershed-scale study was established to develop relationships among land use and water quality within western Georgia. During phase 1 (year one), physio-chemical, biological and morphological measurements were taken within 16 sub-watersheds, ranging in size from 500–2500 ha. Nutrient and fecal coliform concentrations within watersheds with impervious surface > 5% often exceeded those in other watersheds during both baseflow and storm flow. Also, fecal coliform bacteria in more urbanized areas often exceeded the US EPA’s standard for recreational waters. During the second phase of the study, models will be tested and calibrated based on newly chosen watersheds.     

上海城乡统筹发展的路径和突破口研究

上海城乡二元结构的深层次问题突出表现为:城乡居民收入差距仍然明显,促进农民增收的难度加大;郊区人口持续导入,对公共服务和社会管理的要求提高;农村土地和产权制度改革滞后,深化改革的条件尚不成熟;郊区城市化进程加速,管理体制和管理模式亟待转变;新城和小城镇等城乡统筹载体建设有待加强。上海城乡统筹发展要牢牢把握公共服务均等化、发展成果共享化、发展权利平等化内涵,坚持以城带乡、城乡一体、互动发展,以推进新型城市化战略为主攻方向,以加强城乡规划一体化为前提,以加快新城开发建设为突破口,以土地管理、集体产权、社会管理制度改革为支撑,以基本公共服务均等化为着力点,大力推进工业向园区集中、居住向社区集中、农业向规模经营集中,努力实现优化农村土地资源配置方式、优化城乡资源要素流动方式、优化城乡统筹发展方式,推进城乡一体化发展。     

Spatial disintegration and arable land security in Egypt: A study of small- and moderate-sized urban areas

While commonly associated with regional ‘mega-cities’, rapid urbanization in the less-developed world has also begun to define growth in small- and moderate-sized settlements on the periphery of major metropolitan areas. The dispersal of population growth to these smaller areas holds significant implications for environmental, economic, and social health, and threatens local food security, increases congestions, and induces difficulty in service provision. This study examines the effects of spatial disintegration and rapid urbanization in the stock of arable land in Egypt. To assess this issue, the study will meet three objectives. First, we evaluate the relationship between population growth and urban land cover expansion in small- and moderate-sized settlements in Egypt. Second, we consider the role of selected geographic determinants in influencing the growth of these areas through the use of a regression model. The selection of an appropriate model type is a sub-objective and will be discussed further. Third, these drivers of growth will be assessed through their effects on the country’s stock of arable land. These objectives will be met through the development and application of the regression models, in order to examine the relationship between urban land expansion and several independent variables. An increase in population is found to have a positive and statistically significant effect on corresponding urban land cover area. Surprisingly, the variables commonly associated with urbanization in Egypt - proximity to major roads, the capital of Cairo, and the Nile River - though exhibiting a positive relationship with urban growth, are not statistically significant in the selected case studies. This research underlines the necessity for a combined approach to policy formation - with input from policy fields as varied as agriculture, urban planning, and land reclamation - to slow outward growth and maintain arable land stocks.     

Land fragmentation under rapid urbanization: A cross-site analysis of Southwestern cities

Explosive population growth and increasing demand for rural homes and lifestyles fueled exurbanization and urbanization in the western USA over the past decades. Using National Land Cover Data we analyzed land fragmentation trends from 1992 to 2001 in five southwestern cities associated with Long Term Ecological Research (LTER) sites. We observed two general fragmentation trends: expansion of the urbanized area leading to fragmentation in the exurban and peri-urban regions and decreased fragmentation associated with infill in the previously developed urban areas. We identified three fragmentation patterns, riparian, polycentric, and monocentric, that reflect the recent western experience with growth and urbanization. From the literature and local expert opinion, we identified five relevant drivers ?C water provisioning, population dynamics, transportation, topography, and institutions ?C that shape land use decision-making and fragmentation in the southwest. In order to assess the relative importance of each driver on urbanization, we linked historical site-specific driver information obtained through literature reviews and archival analyses to the observed fragmentation patterns. Our work highlights the importance of understanding land use decision-making drivers in concert and throughout time, as historic decisions leave legacies on landscapes that continue to affect land form and function, a process often forgotten in a region and era of blinding change.     

近郊集体所有制土地产权换股权试点方案研究

随着城市化的不断推进,部分农村集体土地被转换为城市建设用地。涉及城市化的农村居民理应分享到土地资源优化配置的财富性收益,同时完成农民到市民的身份转换。上海近郊在城市化过程中对建设用地的需求越来越大,经济发展和保护农民合法权益是必须处理好的一对重要关系。从现有经验看,集体所有制土地产权换股权是合理利用、优化配置郊区集体所有制土地,协调好产业发展与农民权益保障的有效改革路径,也是上海实现包容性城市化发展、消除新二元结构的重要制度创新。     

对我国城市化健康发展的理论思考——城乡统筹发展的视角

本文简要回顾了我国近10年来城市化快速发展的理论和政策背景,指出快速城市化进程中存在土地、能源等自然资源过渡消耗和浪费问题,也存在重城轻乡等突出社会问题;采用人口供需平衡的方法,分析评价了我国人口城市化水平同经济发展水平、工业化水平和土地城市化的关系;对城市化加速理论进行剖析,认为我国当前工业化技术体系不适用于机器技术体系下城市化加速的经验规律,应该结合我国新型工业化的要求走资源节约型的新型城市化道路;建议适当降低城市化发展目标与速度,纠正城市化过程中＂城市偏向＂和＂以物为本＂的做法,体现国家赋予城市化带动农村发展的重任,实现城乡统筹发展。     

农村宅基地流转的风险防范

我国农村宅基地使用权制度产生于计划经济和城乡二元结构背景下,随着社会主义市场经济体制的进一步完善以及全国城市化、工业化的深入发展,这一制度已与城乡一体化、资源集约利用之间产生较大矛盾。进行农村宅基地流转,有利于农村土地集约节约利用;有利于增加农民财产性收入;有利于推进新型城镇化和加快城市化进程;有利于推动农业现代化建设和解决“三农”问题。当前推进农村宅基地流转的关键在于减少农村宅基地数量、盘活土地资源存量、提高土地资源利用效率;在此基础上,兼顾增加农民收入。     

How small cities affect the biodiversity of ground-dwelling mammals and the relevance of this knowledge in planning urban land expansion in terms of urban wildlife

Fundamental principles regarding urban biodiversity are based on studies conducted in large cities. However we cannot know whether the same phenomena occur in smaller cities or how small cities affect biodiversity. Small cities are an inherent element of urbanization and in the future, most global urban growth is expected to take place in small and medium-sized cities. Understanding the effects of small cities on biodiversity will be an important aspect in planning urban land expansion. Our study examined the effects of a small city on communities of small ground-dwelling mammals on 41 sites arranged in a four step gradient of urbanization. In 6700 trap-days, we caught 2333 individuals comprising 15 species. In the downtown area the same phenomena as those described for large cities were observed: a reduction in species richness and diversity, a decline in the abundance of urban sensitive species and an increase in synurbic species. However, in contrast to large city studies, green areas outside the downtown area did not differ from rural sites in small mammal population parameters. This phenomenon of relatively unchanged fauna outside the downtown area shows that small cities have the potential to maintain a high level of diversity of small ground-dwelling mammals if appropriate planning of further building expansion is implemented. More studies of small cities are needed to better assess their impact on biodiversity. This knowledge can then be applied in better planning for urban wildlife. Generalizations based solely on large city studies are inadequate and may lead to incomplete or inappropriate conservation strategies for small cities.     

The effect of fragmentation on the threatened plant community Coastal Moonah Woodland in Victoria,Australia

Coastal vegetation is under increasing pressure with the expansion of urban developments, tourism, population and changing climates. This study sought to examine the effects of fragmentation on the threatened plant community, Coastal Moonah Woodland, in southern Victoria, Australia. We examined the effects on community composition of surrounding land use (urban, rural, native vegetation), remnant size and environmental attributes at three spatial scales. At larger scales, geographic and environmental attributes, such as annual rainfall and temperature, were important drivers of community composition. At finer scales, remnant size, disturbance, weed invasion, connectivity, and immediate surrounding land use impacted more on community composition. At these scales, increasing native vegetation cover in the landscape, remnant connectivity and size positively influenced community composition. If coastal development continues at the current rate, all but a few remnants of this community will be surrounded by the urban landscape. Thus, planning for the integration of these remnants in the urban landscape through long-term management plans and community involvement is essential for the survival of these remnants.     

新型城市化是上海城市发展转型的必由之路

中国在推进城市化进程中,以城市人口占总人口的比例来表示城市化率的方法,实践证明并不科学。目前农村与城市的＂二元结构＂依然很突出。上海作为国内城市化率最高的城市,也有＂概念性市区＂问题,需要走新型城市化道路,在完成＂人口转移型＂城市化前提下,加快向＂结构转换型＂城市化转变。     

Temporal effects on biodiversity and composition of arthropod communities along an urban–rural gradient

Global urbanization is rapidly increasing, yet the prevalence of single order and time point studies likely miss important temporal effects of urbanization on entire communities. We studied three sites along a rural–urban gradient in the Seattle metropolitan area with three sampling periods from 2009–2011 to examine how arthropod communities respond to increasing levels of urbanization in a similar habitat type through time. Consistent with previous studies, urban areas contained altered environmental conditions relevant for litter arthropods, and arthropod biodiversity decreased with urbanization. However, urban arthropod biodiversity was not influenced by environmental measures, supporting the idea of an “urban-filter”. Urbanization was not a factor influencing how communities responded to the effect of time, suggesting that other factors (e.g. disturbance) may ultimately be more important for determining patterns of biodiversity through time in urban areas. Finally, our study illustrates urbanization forces can structuring entire arthropod communities similarly through time, having important consequences for our understanding of urbanization’s temporal effects and indirect influence on community interactions and ecosystem processes. As the effects of urbanization will inevitably vary through time, we suggest that multiple time point studies are required to increase our ability to accurately describe arthropod community responses to increasing urbanization.     

武汉市统筹城乡一体化发展研究

统筹城乡一体化发展是当前推动城乡经济社会发展的迫切任务。本文通过建立指标评估,发现武汉城乡一体化水平略高于城镇化水平;城乡人口、经济、生活和文化一体化进程中,城乡经济发展的差别最为明显,融合程度最低,而城乡居民生活方面则融合程度较高,人口与文化融合度持平。而城乡二元户籍制度、土地的合理开发利用及农民权益保障、农村公共服务投入不足、农村社会保障体系不完善是当前制约城乡一体化发展的重要瓶颈。文章从法律制度层面、财政层面及组织体制层面分析了破解城乡一体化发展瓶颈的重要举措。     

Lentic and lotic odonate communities and the factors that influence them in urban versus rural landscapes

Habitat alteration via urbanization has very different effects on even closely related taxa. Most research investigating the ecological effects of urbanization has focused on birds or mammals, resulting in a relatively poor understanding of how the species richness and community composition of invertebrates may change. We quantified differences in species richness of adult odonates (dragonflies and damselflies) at lentic and lotic sites in urban and rural landscapes, and we examined environmental factors that might drive the differences in community composition that we observed. For lotic sites, species richness did not differ between urban versus rural sites for either dragonflies or damselflies. For lentic sites, urban and rural sites contained similar dragonfly species richness, but damselfly species richness was significantly lower at urban sites than at rural sites. Differences in lentic odonate community composition were associated with the amount of urban development within 150 m of each site, mean algal coverage, and distance to the urban center. At lotic sites, water temperature and distance to the urban center were correlated with differences in odonate community composition. The differing responses to urbanization observed in this study were probably a consequence of differences between lentic versus lotic ecosystems and between dragonflies versus damselflies in dispersal capability and habitat specificity. Given that different environmental factors affected these taxa differently in lentic and lotic sites, maintaining the highest level of odonate diversity possible across a landscape will require the use of different management practices for each ecosystem type.     

Are plant communities mainly determined by anthropogenic land cover along urban riparian corridors?

Often used as a mitigation tool to landscape fragmentation, urban riparian corridors also suffered from the effects of the urban expansion. This study explored the relationships between plant riparian communities and two major environmental variables (land cover, soil characteristics) and analyzed the floristic change along an urbanization gradient. Fifteen sites were surveyed on both riverbanks of two riparian corridors characterized by contrasting water regimes in Strasbourg, North Eastern France. Data of spontaneous species abundance was collected from 180 quadrats using (i) all plant species, (ii) herbaceous stratum and (iii) ligneous stratum (bush and tree). The diversity and compositional patterns of riparian plant species were analyzed within each corridor according to three levels of urbanization (urban, suburban, peri-urban). Relationships between riparian communities, land cover and soil chemical properties (pH, nitrogen and carbon content, moisture) were established by between-class co-inertia analyses. Land cover emerged as the main factor explaining changes in riparian communities along the rural–urban gradient while soil chemical properties discriminate water stress and fluvial dynamics of the two corridors. Similar compositional patterns were found within the most urbanized sites with the establishment of ubiquitous species. The herbaceous stratum is best linked to the level of urbanization, whereas the tree stratum is primarily correlated with corridor attributes (hydrological regime, soil properties). Although riparian species and communities are mainly determined by land cover, urban riparian corridors maintain native biodiversity up to the urban center.     

Direct and indirect effects of human population density and land use on physical features and invertebrates of Iowa (U.S.A.) streams

To improve understanding of human impacts on headwater stream condition, we quantified relationships between human, terrestrial landscape, and stream system variables in 29 central Iowa watersheds. Across study watersheds, between 0 and 100 % of total land area was characterized as “urban” (developed and barren land), whereas cultivated land constituted between 0 and 71 % of watershed area. Several variables were measured for each stream and associated watershed. Strengths of correlative relationships were used to select variables for path analysis, which we used to gain insight into factors affecting stream condition by evaluating direct and indirect effects of human system variables, terrestrial landscape variables, and physical stream variables on stream invertebrates. Results indicated that in predominantly urban watersheds, contaminant inputs to streams (measured by streamwater conductivity) negatively affected invertebrates, including EPT taxa (Ephemeroptera, Plecoptera, Trichoptera), and streamwater contaminant concentrations increased with impervious surface and human population density in the watershed. In rural watersheds, high streamwater nitrogen concentrations associated with cultivated land were related to declines in invertebrate taxon richness. Independent of land use, invertebrate abundance and taxonomic diversity were positively related to coarse substrate abundance on the streambed. Additionally, stream flow (discharge) increased with watershed area, which in turn increased invertebrate taxonomic diversity. Apparently, mechanisms responsible for human impacts on stream condition in central Iowa depend on dominant land use in the watershed. Additionally, stream ecosystems with high quality benthic habitat, and those located in large watersheds with greater flow, appear to be more resilient to land use effects.