Bird communities of the Colorado Rocky Mountains along a gradient of exurban development

Most insights about the effects of residential development on wildlife are based on research from urban and suburban areas. Yet exurban development is an increasingly prevalent form of human settlement in many parts of the world. Moreover because such development often occurs near the periphery of protected areas, it may have a disproportionate influence on native species. We examined bird community patterns in the Rocky Mountains of north-central Colorado across a gradient of exurban development to determine how avifauna responded to this form of settlement. Using fixed-radius point counts, we surveyed the occurrence and abundance of breeding birds in 11 developed sites and in 6 nearby undeveloped sites, all occurring in a forested matrix. We sampled ground-level habitat features at each survey point and derived digital land-cover maps from aerial photographs to characterize and quantify road development and building density. We found little evidence that land-cover varied with development intensity, yet bird abundance increased significantly with building density. Patterns of species richness were equivocal due to a highly influential observation. Principal components analysis (PCA) distinguished two axes that explained nearly 50% of the variation in the bird community and were strongly associated with road and building density. Weighted average analysis showed a marked decline in the abundance and richness of species that were insectivorous or nested in snags, suggesting that reductions in dead wood may have influenced the bird community. However, no conclusions could be drawn because dead wood was confounded with building density. Logistic regression of species occurrence and building density indicated that the incidence of some generalist species increased with building density, whereas the incidence of specialists decreased. Overall, our results suggest that development at low densities can favor habitat generalists. Similar patterns have been observed in more urbanized areas. If exurban development persists as a popular form of settlement in the Rocky Mountains, a regional plan for protecting avian habitat and limiting development dispersion will be necessary to maintain native bird communities.     

Housing density as an indicator of spatial patterns of reported human–wildlife interactions in Northern New York

Compromises in biodiversity and biotic integrity from human development alter native wildlife communities. Anecdotal evidence suggests that increases in residential development contribute to increases in human–wildlife interactions; however, little empirical research has addressed this issue. We tested whether housing density could be used to indicate patterns of reported human–wildlife interactions in Northern New York. We used a novel application of univariate and bivariate K-functions to assess the spatial relationship of reported human–wildlife interactions along a gradient of housing densities. We found that reported human–wildlife interactions are not completely spatially random in Northern New York State and the reports tend to cluster more in areas dominated by suburban and exurban housing densities compared to areas with urban or wildland housing densities. Low-density developments have unintended ecological consequences including an increase in reported human–wildlife interactions. Further work is needed to determine specific reasons for clustering of reported human–wildlife interactions in suburban and exurban areas. However, planners should consider human–wildlife interactions as a potential negative outcome of low-density development and devise development designs, such as clustering, to reduce future human–wildlife conflicts.     

Spatio-temporal trend analysis of long-term development patterns (1900-2030) in a Southern Appalachian County

Many mountainous areas in the U.S. have experienced significant changes in residential development patterns over the past century, in large part due to changing economies and in-migration from outsiders seeking the scenic resources of these areas. To evaluate changes in the Southern Appalachian mountain region, we reconstructed building and road locations in Macon County, North Carolina, since 1906 from historic maps, aerial photographs, county parcel records and emergency response program data. We used these data to analyze growth trends using spatio-temporal classification and quantile regression analysis. We also forecast future development patterns through 2030 using a multi-step model incorporating population growth projections, extrapolations of recent development density trends, and spatial logistic regression models. We characterize new development in the county as primarily rural from 1906 to 1960, exurban from 1960 to 1975 and increasingly suburban since 1975. While the rate of population growth and new building construction peaked in the 1980s, the total road length and rate of development in forested areas continued to increase from 1990 to 2009. We forecast that through 2030 approximately 75% of new buildings will be constructed at urban and suburban densities and that 67% of all new buildings will be constructed in forested areas. In addition to establishing the utility of using spatial analysis to draw together disparate data sources to understand urbanization over long time scales, this analysis identifies trends that have important implications for land-use planning, hydrology, forest management, and wildlife conservation.     

Predicted effects of residential development on a northern Idaho landscape under alternative growth management and land protection policies

Land use change driven by exurban development can lead to dramatic alterations in the structure and function of landscapes. Residential development outside of urban and suburban zones can disrupt agricultural and forest management operations and ecosystem processes, increase community wildfire hazard, deplete groundwater resources, and lead to social conflict. We assessed two policy tools, urban growth boundaries and agricultural use zoning, for their potential to help manage growth and sustain the rural landscape. Using a survey-based model, we simulated the effects of the two policy tools on land use change and compared the results with predictions of land use change for two rural counties (4794 km²) in northern Idaho developed in a previous project. We measured the effects of predicted exurban development using four measures: number of housing units predicted on productive agricultural lands, number of housing units predicted on a groundwater resource area, changes to a wildfire hazard index for residential structures, and the social acceptability of residential development patterns given current development preferences. The two policy tools impose in substantially different landscape-level residential development patterns when compared to the baseline change prediction and each other. Each tool resulted in a variety of tradeoffs between negative and positive effects among our measures of impact. Our findings demonstrate the importance of using multiple indicators to evaluate growth management and land protection policy tools for making land use planning decisions.     

Prioritizing conservation targets in a rapidly urbanizing landscape

We used an optimization modeling framework to devise spatially explicit habitat acquisition and restoration strategies for 19 remnant-dependent butterflies in a rapidly urbanizing county in the Chicago area. We first identified the smallest sets of protected sites that would contain at least one population of each species, and two populations for species present in multiple sites. We then identified undeveloped properties contiguous with these sites whose acquisition would further enhance conditions for focal species. Next, we considered parcels in the surrounding landscape that could potentially be acquired and restored to provide additional habitat. Assuming that the conservation value of additional habitats would increase with their proximity to protected sites, we examined tradeoffs between distance to sites and the cost of acquisition and restoration. The tradeoff curves generated by the model represented choices among sets of reserves that varied widely with regard to cost and distance. Among the non-dominated solutions for a given total area budget, the best solutions depend on the decision makers preference for these two objectives. Sets along the frontier of these curves differed in total cost due to the variation in the number of wetlands per parcel, the number and cost of parcels that must be acquired to provide sufficient habitat, and restoration costs. Several parcels appeared in all solutions and should be prioritized for acquisition. Our general approach is readily adaptable to other locations and planning objectives, but the models would need to be modified to accommodate different target species and their habitat requirements.     

Land-use planning and distribution of threatened wildlife in a city of Japan

The relationships between the distribution patterns of threatened wildlife species and current land-use planning were investigated in a city of Japan to design a sustainable and land-use plan. Spatial distributions of 165 species of threatened wildlife (99 plants and 66 animals) were obtained by surveying most of the Chiba City, located in northeastern part of the Tokyo Bay area. Distribution maps were created within 334 rectangular cells, each measuring 1.1 km×0.9 km, oriented in the cardinal directions. Four land-use zones, i.e., urbanization promotion, parkland, agricultural and urbanization control, and agricultural promotion zones were identified.The distribution of these threatened species was analyzed in terms of green cover and zoning categories. Few threatened wildlife species were found in the urbanization promotion or parkland zone. Most were concentrated in the surrounding arable areas with green covers of more than 50%. Areas other than those set aside for intensive agricultural development in the agricultural promotion development zone contained the greatest number of species. These areas belonged to the agricultural and urbanization control zone, where the traditional agricultural landscape still remains in and around narrow valleys called “yatsu”.The results suggest that the regional biodiversity depends heavily on areas in which the traditional landscape remains relatively intact. Based on these results, a series of recommendations, including conservation and restoration of habitats, establishments of wildlife networks and corridors, and citizen involvement in conservation, were presented to the city studied. The data and recommendations will hopefully help the city, as well as many other areas faced with similar issues, devise future land-use plans that combine sustainable development with conservation of biodiversity and maintenance of high quality living environments.     

Avian movement across abrupt ecological edges: Differential responses to housing density in an urban matrix

The movements of birds across habitat edges were investigated at the interface between remnant bushland and two densities of suburban housing. Behavioural responses to edges adjoining the two densities of housing matrix differed significantly among feeding guilds. Omnivores and nectarivores were significantly more likely than insectivores to penetrate edges adjoining high-density housing. Analysis of individual species revealed several consistent trends. Nectarivorous species appeared more likely to cross at edges of high-density housing, while insectivores were more likely to cross at edges of low-density housing. Regression models suggest these trends may be influenced by characteristics within the matrix, principally the proportion of housing and variables associated with shrub and canopy vegetation. These trends corresponded well with the known distribution of the guilds in remnant vegetation of the suburban landscape. Importantly, by crossing at these habitat edges, many species demonstrate that with appropriate management of the housing matrix they have the potential for dispersal necessary for the maintenance of meta-populations.     

The effects of high-density suburban development on commuter mode choices in Seoul,Korea

This study empirically assesses the effects of high-density suburban development on commuter mode choices in Seoul, Korea. We separated the impacts of densification and new suburban development on mode choice through an examination of interaction effects between population density and the sizes of newly developed suburban areas in logistic regression models. As expected, population and employment densities are positively related to public transit use, while new suburban residential and nonresidential developments are positively related to automobile use. However, the interactive logistic model empirically confirms that a one-unit increase in development density of the new suburban residential increased automobile usage by 27% in 1996 and 17% in 2006 (13% in 1996 and 16% in 2006 for new nonresidential developments), indicating that suburbanization and density are not at odds, but rather are corroborative in encouraging automobile use in the Seoul metropolitan area (SMA). One of the primary explanations for this finding is the strong housing preference for suburban high-rise apartment buildings among SMA residents.     

城市森林建设背景下天敌保护型林地研究

远郊平原林地作为城市森林建设的一部分,由于承载着丰富庞大的生物量和复杂的群落结构,成为农业害虫天敌理想的栖息场所,构建天敌保护型林地对农业害虫的生态调控和实现生态系统的可持续发展具有重要意义。基于国内外文献研究,以天敌保护型林地为综述对象,梳理总结了林地与天敌栖息的关系,分析出林地在树种配置、群落结构和空间格局3个方面对天敌栖息的影响机制,并从4个层面提出合理配置及优化布局的天敌保护型林地营建策略,即营建异龄复层混交林、提升食源植物的比例、营建巢穴庇护空间和增强景观格局异质性,从而构建适宜天敌栖息的多样化林地环境,增强天敌的生态控害保益功能,以期实现城市森林功能的拓展、生物多样性的维持及生态服务功能的提升。     

Habitat associations of a raptor community in a mosaic landscape of Central Spain under urban development

The effects of urban sprawl and the associated road network on patterns of land use by diurnal raptors were assessed in a extent mosaic landscape of Sierra de Guadarrama subjected to exurban development (Madrid province; Central Spain), within the buffer area of a planned national park. During three consecutive years, the sightings of raptors per 0.25 km² were analyzed to identify their habitat preferences according to several vegetation types, urban cover and length of paved roads. Species richness increased with the amount of deciduous forests of Pyrenean oak Quercus pyrenaica and parklands of Narrow-leaved Ash Fraxinus angustifolia in lowland areas, while it decreased with cover of urban/suburban areas. Analyzing the three most abundant species separately, urban development had a negative influence on the Common Buzzard Buteo buteo and the Black Kite Milvus migrans, although positively affected the Booted Eagle Hieraaetus pennatus, probably through an increase in the availability of its potential prey within urban areas. This study did not find a negative influence of the road network, either considering total species richness or the three most abundant species separately. The current levels of urban development diminished the suitability of the study area for the raptor community overall (though particular species can be favoured), notably when residential sprawls are established over ash parklands traditionally devoted to cattle grazing.     

Empowering nature conservation in Japanese rural areas: a planning strategy integrating visual and biological landscape perspectives

There has been much discussion about the importance of nature conservation, but a concrete strategy has been lacking. Most conservation measures are reactive to development projects that threaten the sites’ conservation values. There is little synergy between nature conservation and other competing land-use policies. Furthermore, conservation messages are not communicated well because there are few opportunities for those involved in research, policy formation and policy implementation to interact. We illustrate the methodological framework that can be used to address these issues in rural nature conservation by presenting our research conducted in the Arai-Keinan district of Niigata, Japan. The proposed methodological framework consists of integrating visual and biological landscape approaches to understand the area’s natural environment and using participatory research to narrow the communication gaps among those involved. We stress the importance of expressing the research results and recommendations on a map as a strategy for effective nature conservation. The graphical presentation of a map not only allows for clearer delivery of messages from researchers to government officials and residents, but also facilitates coordination among competing land-use policies. The map is the central ammunition in reversing the reactive nature of conservation policies to that of a “preemptive” nature. Future research directions to gain stronger political support are also discussed.     

Residents' Attitudes to Landscape and Ecology of Idyllic Housing Sites: The Case of South Korea

The demand for idyllic housing has been rapidly spreading from the national capital regions to suburban areas of large metropolitan cities in South Korea. This trend could be seen as a demand for more environmentally friendly residences. This research explores the general characteristics of idyllic housing residents, reasons for moving to idyllic housing sites, general attitudes to the surrounding landscape of residential areas and landscape memory, residents' satisfaction with the landscape and their attitudes to the ecological environment. The main reason for the dissatisfaction with idyllic living was the lack of facilities caused by the Farmland Act. A new law for the development control of idyllic housing sites is needed or the existing law needs to be tightened to address this problem. The research presented here is a first step towards a more comprehensive analysis of idyllic Korean housing and further research is needed.     

Recommendations for design and management of golf courses and green spaces based on surveys of breeding bird communities in Montreal

It has been suggested that golf courses can serve as wildlife habitat, provided key landscape features are present. Breeding bird communities were characterized on six golf courses and six green spaces in the Montreal area, Quebec, Canada. Landscape variables were measured to see which were the best correlates of avian species richness within and across sites. While there was no difference in the mean number of bird species (golf: 31 ± 2.4 SE; green: 33 ± 4.5 SE), golf courses supported fewer total species (golf: 55; green: 66). However, most of the species contributing to the green spaces’ higher cumulative total were found at one site. Species composition differed between golf courses and green spaces, and was most correlated with site size, housing density surrounding the site, and extent of coniferous tree, grass, and vegetated water cover. Our results support the work of others, and suggest that golf course architects can improve habitat quality by: (1) increasing deciduous and coniferous tree cover; (2) increasing native vegetation within and surrounding all water bodies; (3) reducing the amount of highly managed grass area; (4) ensuring large, undeveloped buffers are maintained to prevent a shift in avian community composition with increasing urban sprawl; and (5) ensuring sites are planned as large as possible.     

Effects of land-use master plans in the metropolitan fringe of Japan

The complexity of the landscape in Japanese metropolitan suburbs is the result of high competition among land-demanding economic activities. Although both urban and rural planning legislation has played certain roles in the ordering of land-use, lack of coordination among different zoning systems is still a key issue in the proper development and conservation of limited land. This study investigated the effects of land-use master plans on actual control of land use through maximal utilization of detailed grid data with advanced GIS functions. We analyzed land-use changes in the Osaka metropolitan area for three periods: 1979–1985; 1985–1991; 1991–1996, and compared these changes with the zoning status in each period. This study demonstrates that disordered developments resulted in an increase of vacant areas in urban fringes, which also accelerated the fragmentation of forests and farmlands, causing a disordered spatial pattern from which it will be difficult to recover with the present land-use master plans.     

长三角城市群乡村植被特征与生物 多样性保育策略

长三角一体化绿色发展是中国的重大战略,乡村生态状况是长三角城市群生态健康发展的基础。针对长三角城市群乡村植被生物多样性保育和生态系统服务功能提升需求展开研究,调研了28个乡村共256个植物群落样地,分别进行了科属种构成和生活型分析;通过群落聚类,划分出47个群落类型和8个植被型,分析了植物群落构成和分布特征;进行了物种生物多样性分析,并将长三角乡村植被特征与城市区域和自然区域的植被特征进行比较;最后,从物种保护、生境维护、群落保育和生态美学引导等方面提出了长三角乡村植被生物多样性保育与构建的具体对策。     

Hotspots for Growth

Problem, research strategy, and findings: Our study contributes to the ongoing debate about the ability of Maryland's Priority Funding Area (PFA) program to control urban sprawl. We develop an economic-based land use conversion model to estimate if the PFA program steers urban growth to locations inside targeted growth areas within a fast-growing, exurban county. The results indicate that the size of an agricultural parcel, its distance from urban parcels, its proximity to highways, the productivity of agricultural land, and location in or outside PFAs influence the probability an agricultural parcel will be converted to urban use. We find that some of the parcels experiencing the greatest market pressure for development are located outside PFAs, and Maryland's incentive-based strategy is not completely effective at preventing sprawl.

Takeaway for practice: Careful design of the location of entrances and exits on and off highways, limitation of agricultural parcel fragmentation, and vigilant control of land use change in unproductive agricultural areas can limit sprawl. Our analysis highlights, yet again, the importance of communication between transportation and land use planners.

Research support: The research was supported by funding from the Harry R. Hughes Center for Agroecology, Inc.     

The post-suburban era comes to Richmond: City decline, suburban transition, and exurban growth

The Richmond, Virginia region is an example of a metropolitan area that has entered the post-suburban era. We define the post-suburban era in terms of inner suburban population loss and relative income decline, suburban employment increase, suburban outcommuting reduction, exurban population and income increase, and farmland conversion.The post-suburban era involves the maturing of many suburbs. Maturing suburbs usually increase employment within their borders. The necessity for suburbanites to commute to central cities declines. However suburban maturity also is associated with diminished capacities. Relative income decline in numerous suburbs is the most prominent feature of diminished suburban capacities. Ironically, the stage for relative suburban income decline is set by suburban job increases which expand the commuting zone 20 or 30 more miles into rural territory, greatly enlarging the zone of exurban population growth.     

国际大规模增量住房的建设与实践

大规模增量住房是一种由公共部门和个体家庭共同承担建设成本与社区责任的经济适用居住模式。以逻辑 组织理论为指导，将增量住房划分为自下而上的自组织增量住房和自上而下的他组织增量住房，分别通过印度尼 西亚雅加达的甘榜和秘鲁利马的巴里亚达斯两个案例剖析了两种类型的优点和缺点。最后以哥伦比亚波哥大的巴 楚城为例，将其建设过程分解为由公共部门决策的住区结构规划、用地布局规划和“场地与服务”建设三个阶段， 以及由个体家庭决策的规划增量与未规划增量建设两个阶段，旨在证明双重组织的大规模增量住房是一种兼顾经 济性和公平性的可持续住房供给模式，对实现土地紧凑利用、家庭按需建设和成本持续投入等具有重要意义。     

Evaluating alternative economic growth rates and land use policies for Flathead County, Montana

Nine alternative futures are simulated for Flathead County, Montana for 2000–2014 and 2000–2024. Alternative futures incorporate high, moderate, and low growth rates, and baseline (current), moderately restrictive, and highly restrictive land use policies. Increases in employment are estimated using the IMPLAN regional economic model and translated into acreage requirements for commercial–institutional–industrial (CI&I) units and six types of housing units. Conversion of developable parcels to CI&I and housing units is based on a multiple-criteria score that measures the suitability of developable parcels for various developed uses. Additional jobs and housing units needed to support those jobs increase substantially, particularly for the moderate and high growth rates. Total acreage required for CI&I and housing units exceeds the acreage available for development for the baseline policy with the moderate and high growth rates, and for the moderately restrictive policy with high growth rates. There are no land shortages with any of the growth rates for the highly restrictive land use policy. Moderate and high growth can be sustained through 2024 in Flathead County by implementing a moderately restrictive land use policy if growth rates are moderate, and a highly restrictive land use policy if the growth rates are high.