Assessing risk of large-scale habitat conversion in lightly settled landscapes

Conversion of relatively “wild” areas constitutes a rising threat to the ecological integrity of North American landscapes. As developers seek unprotected, amenity-rich lands, conservation planners require methods to recognize risk and prioritize actions. Most development models and processes are incremental, accumulating change over time and space. By contrast, large-scale amenity development can be rapid and extensive, necessitating “rapid assessment” techniques. For undeveloped lakeshores in the Northern Appalachian/Acadian ecoregion (330 000 km²), we developed a geospatial screening process based on four factors: (1) urban area proximity, (2) attractiveness of amenity (size), (3) regulatory gaps in protection, and (4) likelihood that owners will develop. To assess conversion risk, we added developable zones to the 10 783 large lakes and ponds in the ecoregion and assessed risk to these lands based on four factors at two distances from 15 major urban areas in the region. Thirty-eight of 387 landowners were classified most likely to convert their lands through development, and 11 of these accounted for 97.5% of the total high-risk habitat area (625–1118 km²). Nearly all of the at-risk land (94.6%) lay outside of currently settled areas and most (69.1%) under the purview of a single regulatory agency, the Land Use Regulatory Commission of Maine (LURC). Without rigorous planning by such agencies large-scale, highly dispersed, and rapid conversion of lightly settled, amenity-rich forestland threatens habitat degradation at multiple spatial scales, i.e., local ecosystems themselves (e.g., lakes), surrounding landscapes, and regions.     

居住区道路指标与路网模式研究

根据<城市居住区规划设计规范>规划的居住区相对封闭,具有较好的居住环境,但道路只为内部居民所用,加剧了城市主干道的负荷,与其他居住区连通性差.根据对厦门市居住区实例和国外相关居住区案例的分析,以轨道交通、公共交通和小汽车交通为主导的居住区的路网密度可提高至8 km/km2～12 km/km2,其功能布局应与路网模式相适应.     

Cultural landscapes and landscape ecology in contemporary greenway planning, design and management: a case study

The Appalachian Trail traverses 3300 km (2050 miles) of the Appalachian Mountains from Maine to Georgia in the eastern USA. Except for the Cumberland Valley (the Great Valley of the Ridge and Valley region of the Appalachian Mountains) in Pennsylvania, and a few other valley crossings, the Trail passes primarily along forested ridges. The Cumberland Valley is the longest valley crossing of the Trail—26 km (16 miles) of intensively cultivated prime farmland undergoing residential and commercial development. To secure public ownership of the Trail through this urbanizing landscape, the US Department of the Interior, through the National Park Service, acquired a 600 ha (1500 acre) corridor through the Cumberland Valley to be managed and maintained by the volunteers of the Appalachian Trail Conference. This study was developed by a project team from the Department of Landscape Architecture of The Pennsylvania State University, for the Appalachian Trail Conference, as a set of planning, design, and management recommendations for the newly acquired trail corridor. The method of study involves developing (1) an understanding of the Trail, its history, and its users; (2) a general understanding of the natural and cultural conditions of the region; (3) a more specific inventory, analysis, and assessment of the natural and cultural elements of the trail corridor. This process reveals a corridor landscape containing the interpretable evidence of 250 years of agrarian landscape history and a diverse set of physical environments and biotic communities that have been fragmented by that land use.The two central ideas explored in this paper that underlie the planning and design of the Trail greenway across the Cumberland Valley are, first, the conservation and interpretation of the cultural landscape, and, second, the reduction of habitat fragmentation and enhancement of biological diversity. The product of the planning and design of the corridor land is a set of recommendations intended to direct future actions within the valley corridor. The cultural landscape recommendations focus on maintaining the fabric and interrelationships of the cultural landscape by including a complete representation of both the structural and biotic cultural resources. The ecological recommendations focus on protection of existing natural resources, establishment of forest habitat linkages, and restoration of native plant communities. Finally, two examples of the corridor planning, design, and management study are presented as a case study in greenway planning and design in response to cultural landscape conservation and landscape ecology.     

Assessing the Floristic Diversity of Hedge Networks: a landscape perspective

The type of land cover adjacent to hedges has been shown to influence the species composition of the ground flora. An assessment of the contribution of hedge networks to the biodiversity of landscapes therefore requires information on the relative lengths of hedge associated with different land covers. In the River Tyne catchment, Northern England, the association between hedges and land cover types differed between four landscapes. Overall, the greatest length of hedge was adjacent to arable crops, improved grasslands and roads. Hedges next to improved grassland and roads were the most species-rich, while those adjacent to arable crops were the least species-rich. Species which were common adjacent to arable crops were also common adjacent to other land covers. Hedges adjacent to improved grassland, roads and semi-natural broadleaved woodland supported species which were not common elsewhere in the hedge network. It was also found that hedges with different land cover on each side supported different floras on each side. When planning landscape-scale surveys of hedge biodiversity, it is important to survey both sides of hedges, and sampling should be stratified to include hedges adjacent to the different types of land cover present.     

Assessing the Floristic Diversity of Hedge Networks: A landscape perspective

The type of land cover adjacent to hedges has been shown to influence the species composition of the ground flora. An assessment of the contribution of hedge networks to the biodiversity of landscapes therefore requires information on the relative lengths of hedge associated with different land covers. In the River Tyne catchment, Northern England, the association between hedges and land cover types differed between four landscapes. Overall, the greatest length of hedge was adjacent to arable crops, improved grasslands and roads. Hedges next to improved grassland and roads were the most species-rich, while those adjacent to arable crops were the least species-rich. Species which were common adjacent to arable crops were also common adjacent to other land covers. Hedges adjacent to improved grassland, roads and semi-natural broadleaved woodland supported species which were not common elsewhere in the hedge network. It was also found that hedges with different land cover on each side supported different floras on each side. When planning landscape-scale surveys of hedge biodiversity, it is important to survey both sides of hedges, and sampling should be stratified to include hedges adjacent to the different types of land cover present.     

Edge effects of roads on temperature, light, canopy cover, and canopy height in laurel and pine forests (Tenerife, Canary Islands)

The estimation of the road edge effect is useful to understand changes induced by the road network on ecosystems. Road networks on islands may break ecosystem integrity through microclimate edge effects, which are known to be associated with disturbances to animal and plant communities. Road edge effects have been scarcely studied on oceanic islands. In this paper we studied road edge effects on microclimate and canopy structure in laurel and pine forests in Tenerife (Canary Islands). We assessed depth of road edge effect for temperature at four vertical layers (soil, litter and air at 5 cm and 1.3 m above ground), light intensity, canopy cover and height, in transects running from narrow (6–7 m width) asphalt roads and dust trails to 100 m to the interior of both forests. We used an ANOVA procedure with Helmert difference contrasts to identify the distances along transects over which edge effects were significant. We detected significant gradients for most parameters but they were consistently narrow both within and between forests. In the laurel forest, we detected highly significant gradients for soil temperature, light, and canopy cover and height in both asphalt and unpaved roads. In the pine forest, we detected a highly significant gradient for soil temperature at asphalt roads, and a significant light gradient for both asphalt and unpaved roads. From the road edge to the forest interior, significant temperature changes persisted for only 3 m, light variation persisted for 6 m, and canopy cover and height changed significantly within the first 10 m. Asphalt roads and dust trails revealed different patterns of variation for temperature between edge and interior. No differences were found between the two types of roads in edge-interior trends for light or canopy structure. The abruptness of microclimate and canopy gradients was slightly higher in the laurel forest than in the pine forest, caused by a higher edge contrast in the former. The depth of the road edge effect found in laurel and pine forests was small, but it could have cumulative effects on forest microclimate and forest associated biota at the island scale. Such changes deserve attention by local road managers for planning and design purposes.     

Lock living: Urban sprawl in Mediterranean cities

“Lock living” refers to the importance of security design, consumed as a commodity, in the new suburban residential landscapes of Mediterranean cities. This article summarizes the process of urban sprawl that has developed in the cities of Southern Europe in recent decades. It presents the main consequences of this evolution, regarding changes in residential landscape. Mediterranean cities have been historically characterised by the archetypal image of density, urban complexity and social diversity. However, the increasing development of urban sprawl shows a very different urban scenario. Metropolitan spaces along the edges of the motorways and orbital ring roads are developing the type of residential landscape that was, until not so long ago, exclusively associated with the cities of the Anglo-Saxon urban tradition. New low-density residential areas show the proliferation of territories manifesting the same morphological criteria in different cities. From a cultural perspective, these standardised landscapes mean the production of residential areas designed on the basis of a thematization of the American suburb. This iconographic display dresses them up as private-urban-ecological-thematic paradises, as a residential landscape that becomes image more than territory and, in this sense, a commodity. This commodification process refers both to the residential space and the inhabitants’ lifestyles as the domestic landscape, created by private security, clearly shows.     

A further discussion of the factors controlling the distribution of Pt, Pd, Rh and Au in road dust, gullies, road sweeper and gully flusher sediment in the city of Sheffield, UK

Forty paired road dust and gully sediments from the city of Sheffield in NE England show that high platinum, palladium and rhodium concentrations derived from catalytic converters depend on proximity to both roundabouts rather than traffic lights and to topographic lows. Road dust outside schools and control samples, further away on the same road, show that Pt, Pd and Rh concentrations are dependant on passing traffic flow rather than numbers of stopping vehicles. Highest values of Pt + Pd in road dust are 852 ppb and 694 ppb in gullies. Rh has maximum values of 113 ppb in road dust and 49 ppb in gullies. Pt and Pd values of a few ppb to just over 100 ppb occur in road dust where traffic does not stop, on roads away from junctions. Pt, Pd, Rh and Au are all picked up by road sweepers and gully flushers both with maximum values of just over 100 ppb Pt and Pd. High Au values (maximum 610 ppb in a road dust) were located on pavements, in suburbs, outside schools and in road sweepers collecting in residential areas rather than on high traffic flow roads. Stratification of Pt and Pd in gullies was not observed whereas a high Au value was recorded at the bottom of a gully suggesting gravity concentration for Au. Anomalous Pd grades of 1050 ppb in road dust from a school entrance and 2040 ppb in a street sweeper sample were recorded. These high Pd- and Au-bearing samples do not have anomalous Pt or Rh values and may be sourced from jewellery or dental fillings. However, most samples have consistent Pt/Pd ratios of about 1 and Pt/Rh values of 4 to 5 indicating a catalytic converter source. Pt and Pd are concentrated in road dust at levels well above background in all the samples, including on high and low traffic flow roads.     

Spatial heterogeneity and diversity of vegetation at the landscape level in Inner Mongolia, China, with special reference to water resources

Inner Mongolia, China, was divided into five different areas (landscapes) based on the annual overland flow of water (AOF): <2, 2–5, 5–10, 10–50, and >50 mm. Two maps of plant communities with a 1-cm² grid and the AOF were overlaid (scale: 1 cm = 15 km). Each plant community that occurred in each 1 cm × 1 cm cell (S-cell) was recorded, and the number of occurrences of each community type was counted for groups of four neighboring S-cells (L-cell). These data were statistically analyzed using the power law for each of the five landscapes. The per L-cell community richness and diversity for dry (AOF < 2 mm) and subhumid (AOF > 50 mm) landscapes were low compared to those of the three mesic landscapes (2–50 mm AOF). Community spatial heterogeneity was low in mesic landscapes. The dry and subhumid landscapes consisted of a small number of community types and exhibited monotonous spatial change, while the mesic landscapes consisted of rich plant communities that were spatially intermingled because natural conditions, such as climatic and edaphic conditions, in the landscapes are complex and divided into small areas, and, furthermore, historical anthropogenic activities such as livestock grazing, especially in landscapes with AOFs of 2–50 mm, have divided the landscape into small fragments.     

Reducing habitat fragmentation by minor rural roads through traffic calming

The rural road network suffers continually from ambiguity. On the one hand, the presence of this network and its traffic flows offer accessibility and make a contribution to economic development. While on the other, its presence and its traffic flows cause fragmentation. The actual ecological impact of this fragmentation depends on several variables such as species and road characteristics. This paper focuses on minor rural roads. The spatial concept developed to address this, ‘traffic calming rural area’ (TCRA) is intended to address both accessibility and sustainable environment. It does this by concentrating the current diffuse traffic flows on a few rural highways, thus, creating rural residential areas within the region. This paper presents some formulae to quantify the resulting fragmentation. A more practical method compares the sizes of continuous landscape units. Both the formulae and the method have been used for two pilot studies. The results indicate that implementing the TCRA concept leads to larger continuous landscape units, thereby helping to reduce fragmentation effects.     

Ecological networks: A spatial concept for multi-actor planning of sustainable landscapes

In this paper, we propose the ecological network concept as a suitable basis for inserting biodiversity conservation into sustainable landscape development. For landscapes to be ecologically sustainable, the landscape structure should support those ecological processes required for the landscape to deliver biodiversity services for present and future generations. We first show that in multifunctional, human-dominated landscapes, biodiversity conservation needs a coherent large-scale spatial structure of ecosystems. Theory and empirical knowledge of ecological networks provides a framework for the design of such structures. Secondly, ecological networks can bridge the paradox between reserve conservation (fixing nature in space and time) and development, which implies change. This is because ecological networks can change structure without losing their conservation potential. Thirdly, ecological networks facilitate stakeholder decision-making on feasible biodiversity goals. They help to focus on an effective spatial scale. We conclude that extending the ecological network concept with multifunctional indicators is a promising step towards sustainable landscape development and stakeholder decision-making.     

Restoration ecology studies at Cazarils (southern France): Biodiversity and ecosystem trajectories in a mediterranean landscape

Restoration ecology (RE) offers a conceptual meeting ground and methodological approaches for all those concerned with the past, present and future of ecosystems and landscapes. It combines ecological theory, nature conservation concerns and recognition of the need to develop new management tools for ecosystems and landscapes. In our approach, ‘vital ecosystem attributes' (VEAs) of ecosystems and landscapes are monitored along transects permitting detailed assessment of the impact of economic and RE interventions at the scale of whole landscapes. This also enables quantitative and qualitative comparisons among ecosystems and/or among landscapes. At a new long-term ecological research site (LTER) at Cazarils, southern France, we are studying ecosystem and landscape responses to past and present human uses and perturbations, and to contemporaneous interventions aimed at restoration, rehabilitation and landscape reintegration. In this paper, we present selected baseline data of landscape-wide ranges concerning several different VEAs of both above- and below-ground components of biodiversity as well as soils. The purpose is to describe an approach to landscape research planning and ecosystem management in areas with complex geomorphological, ecological and cultural–historical features such as the Mediterranean region, and surrounding arid or semiarid lands.     

上海城区主要交通绿带木本植物多样性分析

通过上海城区三条主要交通干道绿带的乔木层和灌木层物种丰富度指数，Simpson指数，Shannon-Weiner指数和Pielou均匀度指数的分析，结合群落物种组成、群落类型以及1公里绿带木本植物丰富度的比较，对绿带木本植物多样性进行了比较分析，并进一步讨论了交通绿地物种多样性存在的问题和改善途径。     

Landscape heterogeneity correlates with recreational values: a case study from Swedish agricultural landscapes and implications for policy

Agri-environmental schemes are often targeted at heterogenic landscapes to support several ecosystem services besides food production. The question is whether heterogenic landscapes also support recreation values. Previous studies suggest this but statistical analysis of the relation between heterogeneity and recreation is lacking. To assess this, we used a quantitative Landscape Heterogeneity Index (LHI), developed for biodiversity conservation. We asked five different user groups to score 12 photographs of landscapes depicting different LHI. All user groups, especially conservationists and hunters, preferred the heterogeneous landscapes and this difference was statistically significant for all groups except farmers. Accessibility, in terms of roads, had no obvious impact on the recreational value conveyed by the photos. The paper provides evidence that the recreational value amplifies biodiversity-based values of heterogeneous landscapes and argues that such landscapes also provide resilience and insurance value buffering against unexpected risks. Implications for policy are discussed.

Highlights ? Recreational value was positively correlated to landscape heterogeneity.

? This correlation was statistically significant for all user groups except farmers.

? Accessibility, in terms of roads, had no obvious impact on the recreational value.

? The multi-functionality of heterogeneous agricultural landscapes including resilience and the insurance value should be better acknowledged in policy.

     

Cultural Heritage of Roads and Road Landscapes: Classification and Insights on Valuation

Over time roads and their surroundings gained historic and cultural significance. This significance is oftentimes acknowledged and numerous roads and road infrastructure objects with their surrounding environment are listed and protected. Notwithstanding this, it is necessary to note that the ways in which roads, their surrounding environment, and adjacent objects can manifest heritage values, can be complex, and are not limited to historic roads or historic road landscapes. Different categories of these ways can be distinguished: road landscape can be recognized as cultural heritage, cultural heritage objects functionally related or unrelated to the road can exist in its surrounding environment, and roads can also be treated as cultural heritage objects in landscape. Understanding the dimensions of the cultural heritage of roads and road landscapes and analysing its values can be important not only to the environmental, technological, and cultural history, but also to the future-oriented heritage management and territorial planning fields. The article is aimed to present a framework for analysing the cultural heritage of the automobile roads and road landscapes consisting of the system for its classification and of identification of factors determining its cultural value and the categories of economic value it can provide. Assessment possibilities of these values are also shortly discussed.     

Cliff roads: An ecological conservation technique for road construction in mountainous regions of China

Cliff ecosystems are important for biodiversity protection because these sites often support surprisingly ancient and diverse communities, including rare plants and lichens, trees, birds, and small mammals. To protect Chinese cliff ecosystems, an ancient cliff road construction technique is now being used. To understand the environmental benefits of this approach, we monitored eight cliff road sites in the warm Shennongjia region of China's Hubei Province from June 2006 to July 2009 during road construction. Compared with the traditional filling in of roadside slopes or bridge construction formerly used for highway construction in this area, the cliff highway technique, which combines cantilevered slab roads along the edge of the cliff with bridge support structures where additional support is required, reduces environmental damage and represents a good option for the conservation of fragile cliff ecosystems, while greatly reducing the construction cost. In such areas, the basic objectives of road construction must include biodiversity protection and careful control of the construction process and subsequent cleanup of the site, which cannot be ignored as a result of concentrating on the goal of using the roads to promote regional economic and tourism development.     

Spatiotemporal changes of landscape pattern in response to urbanization

The combined method of urban gradient analysis and landscape metrics in analyzing the changes of landscape pattern has been widely applied since its introduction by Luck and Wu (2002). In order to address the temporal dynamics of landscape change, this study integrated transect analysis with temporal trend analysis and specifically discussed how changes of residential pattern are related to forms of urban growth. Using Dane County, Wisconsin, USA as an example, a 60 km transect passing through the City of Madison was set up to represent a continuum of rural-urban-rural landscapes. Changes of landscape pattern from 1968 to 2000 were analyzed by FRAGSTATS with four metrics—percentage of landscape (PLAND), Shannon's evenness index (SHEI), patch density (PD), and mean patch size (MPS). Findings from metric analyses revealed that the degree of land-use diversity and landscape fragmentation is positively related to the degree of urbanization.Specifically, at the class-level, residential land-use type shows the strongest positive relationship to the degree of urbanization in all of the class-level metrics adopted. Changes in residential land-use pattern were further analyzed with the number of housing units. The analyses revealed that there are different patterns of residential development along the transect in the study area—with the core urban area expanding outward in a contiguous manner while the rural areas have scattered development. This study demonstrated the additional insights into landscape change by integrating the spatial and the temporal perspectives and by targeting the forms of residential developments.     

浅议居住区人·车·路的关系

针对城市小汽车数量快速增加带来的居住区交通环境问题,阐述了以人为中心的人.车.路三者的关系,就城市居住区道路与居民户外活动特点,以及汽车对居住区道路和居民的影响作了论述,并提出建立居住区道路复合空间的建议。     

Evaluation of ornamental plant resources to urban biodiversity and cultural changing: A case study of residential landscapes in Trabzon city (Turkey)

The residential vegetation features in urban landscapes play an important role as indicators regarding urban biodiversity potential and cultural changing. They also include ornamental resources in the context to landscape appreciation for human environment. Therefore, this paper provides quantitative information on the distribution of plant species in urban residential landscape areas of Trabzon city (Turkey). In a total of 218 sampled areas, 274 plants species belonging to 70 families were surveyed with respect to residential use types of the city. The study results showed that among the species recorded in five residential type (traditional housing, detached housing, villa, apartment blocks and sites, mass housing for employees), non-native taxa frequency of a total species are much and dominantly represent residential landscape structure. Additionally, the species richness and diversity is positively related to new urban development areas. But, it was clearly determined that the vegetation structure has tended to ornamental purposes different from traditional residential gardens including fruit and other benefiting species. Consequently, it can be evidence that the residential vegetation is ornamental plant resources to urban biodiversity and that the distribution of the species in urban landscapes follows necessities of city and human quality.     

Regional analysis of the effect of paved roads on sodium and chloride in lakes

Salinization of surface water from sodium chloride (road salt) applied to paved roads is a widely recognized environmental concern in the northern hemisphere, yet practical information to improve winter road management to reduce the environmental impacts of this deicer is lacking. The purpose of our study was to provide such information by developing baseline concentrations for sodium and chloride for lakes in watersheds without paved roads, and then determining the relationship between these ions and density, type, and proximity of paved roads to shoreline. We used average summer (June-September) sodium and chloride data for 138 lakes combined in a watershed based analysis of paved road networks in the Adirondack Park of New York, U.S.A. The watersheds used in our study represented a broad range in paved road density and type, 56 of which had no paved roads. Median lake sodium and chloride concentrations in these 56 watersheds averaged 0.55 and 0.24 mg/L, respectively. In contrast, the median sodium and chloride concentrations for the 82 lakes in watersheds with paved roads were 3.60 and 7.22 mg/L, respectively. Paved road density (lane-km/km²) was positively correlated with sodium and chloride concentrations, but only state roads were significantly correlated with sodium and chloride while local roads were not. State road density alone explained 84 percent of the variation in both ions. We also successfully modeled the relationship between road proximity to shoreline and sodium and chloride concentrations in lakes, which allowed us to identify sections of road that contributed more to explaining the variation in sodium and chloride in lakes. This model and our approach could be used as part of larger efforts to identify environmentally sensitive areas where alternative winter road management treatments should be applied.