Forest fragmentation as an economic indicator

Despite concern over the ecological consequences of conversion of land from natural cover to anthropogenic uses, there are few studies that show a quantitative relationship between fragmentation and economic factors. For the southside economic region of Virginia, we generated a surface (map) of urbanization pressure by interpolation of population from a ring of cities surrounding the region. The interpolated map showed a geographic gradient of urbanization pressure or demand for land that increased from northwest to southeast. Estimates of forest fragmentation were moderately correlated with the geographic gradient of urbanization pressure. The fragmentation-urbanization relationship was corroborated by examining land-cover change against the urbanization map. The geographic gradient in land-cover change was strongly correlated with the urbanization pressure gradient. The correspondence between geographic gradients in land-cover change and urbanization pressure suggests that forest fragmentation will occur at a greater rate in the eastern portion of the southside economic region in the future.     

Transitions in forest fragmentation: implications for restoration opportunities at regional scales

Where the potential natural vegetation is continuous forest (e.g., eastern US), a region can be divided into smaller units (e.g., counties, watersheds), and a graph of the proportion of forest in the largest patch versus the proportion in anthropogenic cover can be used as an index of forest fragmentation. If forests are not fragmented beyond that converted to anthropogenic cover, there would be only one patch in the unit and its proportional size would equal 1 minus the percentage of anthropogenic cover. For a set of 130 watersheds in the mid-Atlantic region, there was a transition in forest fragmentation between 15 and 20% anthropogenic cover. The potential for mitigating fragmentation by connecting two or more disjunct forest patches was low when percent anthropogenic cover was low, highest at moderate proportions of anthropogenic cover, and again low as the proportion of anthropogenic cover increased toward 100%. This fragmentation index could be used to prioritize locations for restoration by targeting watersheds where there would be the greatest increase in the size of the largest forest patch.     

Analysing land-cover changes in relation to environmental variables in Hesse,Germany

Land-use and land-cover changes affect ecological landscape functions and processes. Hence, landscape ecologists have a central interest in a comprehensive understanding of such changes. Our study focuses on the relationships between environmental conditions and agricultural land-cover changes. We present a method to (i) characterise the major spatial-temporal processes of land-cover changes, (ii) identify the correlations between environmental attributes and land-cover changes and (iii) derive potential environmental drivers of land-cover changes in a German marginal rural landscape. The method was applied to study land-cover dynamics from 1945 to 1998 in the districts of Erda, Steinbrücken and Eibelshausen, situated in the marginal rural landscape of the Lahn-Dill Highlands, Germany. We employed land-cover data gained by the interpretation of multi-temporal aerial photographs. Various environmental variables were introduced into the analyses. We identified physical landscape attributes (elevation, slope, aspect, available water capacity and soil texture) and structural landscape dimensions (patch size, patch shape and distance between patch and nearest settlement). With the aid of GIS, K-means partitioning and canonical correspondence analysis, we investigated land-cover trajectory types, land-cover transitions at individual time intervals and their relationships to these environmental variables. Our results show that, between 1945 and 1998, land-cover changes correlated with the physical attributes of the underlying landscape. On the other hand, the structural landscape dimensions correlated with land cover only in periods of minor land-cover changes (1972–98). Greater diversity of physical landscape attributes is correlated with greater land-cover dynamics. Besides the important influence of socio-economic factors, land-cover changes in the study areas took place within the relatively stable physical constraints of the underlying landscape.This revised version was published online in May 2005 with corrections to the Cover Date.     

A systematic review on the ecosystem services provided by green infrastructure

Urbanization and climate change are endangering the sustainability of public spaces through increased land artificialization, ecological fragmentation, reduced resource availability, and limited accessibility to natural and seminatural areas. Properly managing Green Infrastructure (GI) can contribute to mitigating these challenges by delivering multiple provisioning, regulating, supporting and cultural Ecosystem Services (ES). This would facilitate the implementation of strategically planned GI networks in cities for urban regeneration purposes. In this context, this study developed a systematic review on the ES provided by GI using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. The analysis of 199 eligible articles indicated that more efforts should be made to address more ES at once, which connects to the need for conceiving GI as a strategically planned network of areas aimed at delivering diverse benefits. Based on the methods used in the items reviewed, geoprocessing tools and multi-criteria decision analysis are proposed to develop systems of indicators capable of accounting for multiple ES. These systems should also rely on multidisciplinary and participative procedures to encompass various facets of GI and represent the priorities of all relevant stakeholders.     

Driving forces of landscape change - current and new directions

The concept of driving forces is gaining increasing attention in landscape-change research. We summarize the state of the art of this field and present new conceptual and methodological directions for the study of driving forces of landscape changes. These new directions address four major challenges faced by landscape-change studies, i.e., studying processes and not merely spatial patterns, extrapolating results in space and time, linking data of different qualities, and considering culture as a driver of landscape change. The proposed research directions include: studying landscape change across borders and transects, focusing on persistence as well as change, investigating rates of change, considering attractors of landscape change, targeting correlation and causality, and searching for precursors of landscape change. Based on established knowledge and the new approaches we outline a standard procedure to study driving forces of landscape change. We anticipate that our analytical and systematic approach increases the relevance of studies of landscape change for science as well as for the solution of real world problems.     

Driving forces of landscape change - current and new directions

The concept of driving forces is gaining increasing attention in landscape-change research. We summarize the state of the art of this field and present new conceptual and methodological directions for the study of driving forces of landscape changes. These new directions address four major challenges faced by landscape-change studies, i.e., studying processes and not merely spatial patterns, extrapolating results in space and time, linking data of different qualities, and considering culture as a driver of landscape change. The proposed research directions include: studying landscape change across borders and transects, focusing on persistence as well as change, investigating rates of change, considering attractors of landscape change, targeting correlation and causality, and searching for precursors of landscape change. Based on established knowledge and the new approaches we outline a standard procedure to study driving forces of landscape change. We anticipate that our analytical and systematic approach increases the relevance of studies of landscape change for science as well as for the solution of real world problems.     

Changes in land-use/land-cover patterns in Italy and their implications for biodiversity conservation

Land-use/land-cover change is the most important factor in causing biodiversity loss. The Mediterranean region has been affected by antropic disturbance for thousands of years, and is, nowadays, one of the most significantly altered hotspots in the world. However, in the last years a significant increase in forest cover has been measured. These new patterns are independent from planned conservation strategies and appear to have a substantial impact on landscapes and biodiversity. We used three land-use/land-cover maps (from 1960 to 2000) covering the Italian peninsula to analyze the pattern of land-use/land-cover change. We measured an increase in forests, especially in mountains, an increase in artificial areas, especially in coastal zones, and a decrease in pastures. Intensively cultivated areas showed a limited decrease while extensively cultivated ones showed a marked decrease. In the same period mammal and bird species followed a similar pattern, with forest birds, ungulates and carnivores increasing, and typically Mediterranean species decreasing. We suggest that our results may provide important information, which could be useful for conservation planning in the entire Mediterranean hotspot. We suggest that an increasing conservation effort should be made to protect the Mediterranean-type forests and scrublands, as well as traditional agricultural practices. Moreover, future conservation efforts should consider the broad socio-political and ecological processes that are most likely to occur across the whole hotspot, especially along coastal areas, and the network of protected areas should be functionally integrated in a conservation strategy that includes the human-dominated landscape.     

Temporal patterns of ecosystem processes on simulated landscapes in Glacier National Park,Montana, USA

The mechanistic, spatially-explicit fire succession model, Fire-BGC (a Fire BioGeoChemical succession model) was used to investigate long-term trends in landscape pattern under historical and future fire regimes and present and future climate regimes for two 46000 ha landscapes in Glacier National Park, Montana, USA. Fire-BGC has two spatial and temporal resolutions in the simulation architecture where ecological processes that act at a landscape level, such as fire, are simulated annually from information contained in spatial data layers, while stand-level processes such as photosynthesis, transpiration, and decomposition are simulated both daily and annually. Fire is spread across the landscape using the FARSITE fire growth model and subsequent fire effects are simulated at the stand-level. Fire-BGC was used to simulate changes in landscape pattern over 250 years under four scenarios: (1) complete fire exclusion under current climate, (2) historical wildfire occurrence and current climate, (3) complete fire exclusion under a possible future climate, (4) future wildfire occurrence and future climate. Simulated maps of dominant tree species, aboveground standing crop, leaf area index, and net primary productivity (NPP) were contrasted across scenarios using the metrics of patch density, edge density, evenness, contagion, and interspersion. Simulation results indicate that fire influences landscape pattern metrics more that climate alone by creating more diverse, fragmented, and disconnected landscapes. Fires were more frequent, larger, and more intense under a future climate regime. Landscape metrics showed different trends for the process-based NPP map when compared to the cover type map. It may be important to augment landscape analyses with process-based layers as well as structural and compositional layers.     

Land-use and land-cover dynamics in response to changes in climatic,biological and socio-political forces: the case of southwestern Ethiopia

Few studies of land-use/land-cover change provide an integrated assessment of the driving forces and consequences of that change, particularly in Africa. Our objectives were to determine how driving forces at different scales change over time, how these forces affect the dynamics and patterns of land use/land cover, and how land-use/land-cover change affects ecological properties at the landscape scale. To accomplish these objectives, we first developed a way to identify the causes and consequences of change at a landscape scale by integrating tools from ecology and the social sciences and then applied these methods to a case study in Ghibe Valley, southwestern Ethiopia. Maps of land-use/land-cover change were created from aerial photography and Landsat TM imagery for the period, 1957–1993. A method called `ecological time lines' was developed to elicit landscape-scale explanations for changes from long-term residents. Cropland expanded at twice the speed recently (1987–1993) than two decades ago (1957–1973), but also contracted rapidly between 1973–1987. Rapid land-use/land cover change was caused by the combined effects of drought and migration, changes in settlement and land tenure policy, and changes in the severity of the livestock disease, trypanosomosis, which is transmitted by the tsetse fly. The scale of the causes and consequences of land-use/land-cover change varied from local to sub-national (regional) to international and the links between causes and consequences crossed scales. At the landscape scale, each cause affected the location and pattern of land use/land cover differently. The contraction of cropland increased grass biomass and cover, woody plant cover, the frequency and extent of savanna burning, and the abundance of wildlife. With recent control of the tsetse fly, these ecological changes are being reversed. These complex patterns are discussed in the context of scaling issues and current conceptual models of land-use/land-cover change.     

Issues related to the detection of boundaries

Ecotones are inherent features of landscapes, transitional zones, and play more than one functional role in ecosystem dynamics. The delineation of ecotones and environmental boundaries is therefore an important step in land-use management planning. The delineation of ecotones depends on the phenomenon of interest and the statistical methods used as well as the associated spatial and temporal resolution of the data available. In the context of delineating wetland and riparian ecosystems, various data types (field data, remotely sensed data) can be used to delineate ecotones. Methodological issues related to their detection need to be addressed, however, so that their management and monitoring can yield useful information about their dynamics and functional roles in ecosystems. The aim of this paper is to review boundary detection methods. Because the most appropriate methods to detect and characterize boundaries depend of the spatial resolution and the measurement type of the data, a wide range of approaches are presented: GIS, remote sensing and statistical ones.     

A GIS-based mapping methodology of urban green roof ecosystem services applied to a Central European city

Green roofs provide a number of different urban ecosystem services (UESS), e.g. regulation of microclimate, support of air quality improvement, or stormwater retention. To estimate the spatial variation of green roof UESS across an urban area, a GIS-based mapping and spatial analysis methodology was established and applied to the city of Braunschweig, Germany. Based on the analysis of available geodata, in a first step, a quantity of 14,138 rooftops in the study area (14% of all buildings) was found to be generally suitable for greening. This resulted in a green roof area of 3 km². Based on criteria such as roof slope and minimum roof size, nearly two-thirds of these buildings (8596 buildings, 8.6% of total number of buildings) were categorised ‘appropriate’ for greening and subject to green roof UESS analysis.The spatial distribution of green roof UESS was estimated based on the categories thermal urban climate, air quality, stormwater retention and biodiversity. Due to their potential benefits in the four UESS categories an overall assessment resulted in a number of 867 roofs (0.9% of total number of buildings) categorised as ‘high benefit’ from rooftop greening. Another 3550 buildings (3.5%) and 4179 buildings (4.2%) were defined as ‘moderate benefit’ and ‘low benefit’, respectively. The inner city area of Braunschweig appears as a hot-spot of green roof UESS, i.e. higher percentage of ‘high benefit’ green roofs in comparison to residential areas. The proposed method is a simple but straightforward approach to analyse urban green roof UESS and their spatial distribution across a city but it is sensitive to the quality of the available input geodata.     

Agricultural land-use patterns and soil erosion vulnerability of watershed units in Vietnam’s northern highlands

Since the mid eighties, agricultural development and increased population growth in Vietnam’s northern highlands have modified land use patterns and thus, increased the runoff process and soil degradation induced by water erosion. In the last decade, Vietnamese literature has focused on the computation of soil losses over large areas. Most of these spatial and quantitative soil erosion studies do not consider the impact of agricultural land use diversity (spatial heterogeneity), particularly at the watershed scale, and the annual variability of seasonal landscape factors on soil erosion vulnerability and hence, landscape dynamics. We present an integrated approach combining field measurements and observations, GIS and modeling to determine the spatial and temporal dynamics of soil erosion vulnerability according to watershed units and hence, the impact of physical environment components and agricultural land use patterns on landscape evolution. Tables and graphics showing the cropping systems, the periods within a year, and the watershed units that are most vulnerable are presented. The double cultivation cycles for paddy rice fields not only imply two periods of land preparation and establishment that expose the soil surface to raindrop impacts, but also increased soil management practices that decrease the soil’s resistance to detachment. Despite the low levels of soil management practices for the shifting cultivation system, the near absence of soil conservation practices clearly increases their vulnerability. Hence, rainfed cropping systems, mainly soya and cassava, cultivated on sloping lands (hills and mountains) where soil erosion vulnerability is the highest represent the watershed units which are the most prone to soil loss.     

Community perceptions of ecosystem services and disservices linked to urban tree plantings

The planting of trees in streets and parks is critical for urban greening efforts that seek to improve climate-change resilience in cities around the world. Ecosystem services provided by urban trees range from mitigating urban heat island effects to enhancing human well-being and conserving native biodiversity. At the same time, such tree services trade off with disservices that include risk to human safety from falling branches and infrastructure damage from root growth. Here, we performed a survey of residents of a sub-tropical region in eastern Australia to determine community perceptions of the ecosystem services and disservices linked to urban tree plantings. Our aim was to better understand the diverse perceptions of the community, prior to on-the-ground implementation of urban greening, to help guide planting programs in streets and parklands that are vulnerable to UHI effects in the region. We found strong evidence for a high level of public awareness about the beneficial ecosystem services that urban trees can provide. A broad spectrum of beneficial tree services were valued highly by the community in their urban environment including the planting of native trees that can attract and provide food for preferred wildlife; provide shade and reduce heat; allow for a strong connection with nature; have the potential to store carbon to mitigate climate change; provide a level of protection from bushfires; have aesthetically pleasing properties; and produce food for people. At the same time, however, community concerns about tree disservices were concentrated primarily on root damage to infrastructure as well as property damage and injury from falling branches. Our elicitation of community attitudes to tree services and disservices will allow for residents’ most important values and strongest concerns about trees to be explicitly taken into account when establishing a community-inclusive approach to urban tree planting.     

Longterm response of disturbance landscapes to human intervention and global change

The structure of landscapes subject to patch-forming catastrophic disturbances, or disturbance landscapes, is controlled by the characteristics of the disturbance regime, including the distribution of disturbance sizes and intervals, and the rotation time. The primary landscape structure in disturbance landscapes is the structure of the mosaic of disturbance patches, which can be described by indices such as patch size and shape.The purpose of this research was to use a geographical information system-based spatial model (DISPATCH) to simulate the effects of the initial density of patches on the rate of response to alteration of a disturbance regime, the effects of global warming and cooling, and the effects of fragmentation and restoration, on the structure of a generalized temperate-zone forested disturbance landscape over a period of 400 yr.The simulations suggest that landscapes require 1/2 to 2 rotations of a new disturbance regime to adjust to that regime regardless of the size and interval distributions. Thus alterations that shorten rotations, as would be the case if global warming increases fire sizes and decreases fire intervals, produce a more rapid response than do alterations that lengthen rotations, such as cooling and fire suppression. Landscape with long rotations may be in perpetual disequilibrium with their disturbance regimes due to a mismatch between their adjustment rate and the rate of climatic change. Landscapes with similar rotation times may have different structures, because size and interval distributions independently affect landscape structure. The response of disturbance landscapes to changing disturbance regimes is governed by both the number and size of patch births.     

Rice production and climate change: design and development of a GIS database to complement simulation models

A cooperative project between the International Rice Research Institute in Los Baños, Philippines, and the U.S. EPA Environmental Research Laboratory in Corvallis, Oregon, was initiated to estimate how rice yield in Asia might be affected by future climate change and enhanced UV-B irradiance following stratospheric ozone depletion. A radiative transfer model was used to estimate daily UV-B irradiance levels using remotely sensed ozone and cloud cover data for 1274 meteorological stations. A rice yield model using daily climatic data and cultivar-specific coefficients was used to predict changes in yield under given climate change scenarios. This paper gives an overview of the data required to run these two models and describes how a geographical information system (GIS) was used as a data pre- or postprocessor. Problems in finding reliable datasets such as cloud cover data needed for the UV-B radiation model and radiation data needed for the rice yield model are discussed. Issues of spatial and temporal scales are also addressed. Using simulation models at large spatial scales helped identify weaknesses of GIS data overlay and interpolation capabilities. Even though we focussed our efforts on paddy rice, the database is not intended to be system specific and could also be used to analyze the response of other natural systems to climatic change.     

Anthropogenic influences on potential fire spread in a pyrogenic ecosystem of Florida, USA

Fire has historically been an important ecological factor maintaining southeastern U.S. vegetation. Humans have altered natural fire regimes by fragmenting fuels, introducing exotic species, and suppressing fires. Little is known about how these alterations specifically affect spatial fire extent and pattern. We applied historic (1920 and 1943) and current (1990) GIS fuels maps and the FARSITE fire spread model to quantify the differences between historic and current fire spread distributions. We held all fire modeling variables (wind speed and direction, cloud cover, precipitation, humidity, air temperature, fuel moistures, ignition source and location) constant with exception of the fuel models representing different time periods. Model simulations suggest that fires during the early 1900's burned freely across the landscape, while current fires are much smaller, restricted by anthropogenic influences. Fire extent declined linearly with patch density, and there was a quadratic relationship between fire extent and percent landscape covered by anthropogenic features. We found that as little as 10 percent anthropogenic landcover caused a 50 percent decline in fire extent. Most landscapes (conservation or non-conservation areas) are now influenced by anthropogenic features which disrupt spatial fire behavior disproportionately to their actual size. These results suggest that land managers using fire to restore or maintain natural ecosystem function in pyrogenic systems will have to compensate for anthropogenic influences in their burn planning. This revised version was published online in May 2005 with corrections to the Cover Date. This revised version was published online in July 2006 with corrections to the Cover Date.     

Cumulative effects of roads and logging on landscape structure in the San Juan Mountains,Colorado (USA)

In the southern Rocky Mountains of temperate North America, the effects of Euro-American activities on disturbance regimes and landscape patterns have been less ubiquitous and less straightforward in high-elevation landscapes than in low-elevation landscapes. Despite apparently little change in the natural disturbance regime, there is increasing concern that forest management activities related mainly to timber harvest and to the extensive network of roads constructed to support timber harvest, fire control, and recreation since the late 1800s have altered disturbance regimes and landscape structure. We investigated the magnitude of change in landscape structure resulting from roads and logging since the onset of timber harvest activities in 1950. We found limited evidence for significant impacts in our study area when all lands within the landscape were considered. The relatively minor changes we observed reflected the vast buffering capacity of the large proportion of lands managed for purposes other than timber (e.g., wilderness). Significant changes in landscape structure and fragmentation of mature forest were, however, evident on lands designated as suitable timberlands. Roughly half of the mature coniferous forest was converted to young stands; mean patch size and core area declined by 40% and 25%, respectively, and contrast-weighted edge density increased 2- to 3-fold. Overall, roads had a greater impact on landscape structure than logging in our study area. Indeed, the 3-fold increase in road density between 1950–1993 accounted for most of the changes in landscape configuration associated with mean patch size, edge density, and core area. The extent of area evaluated and the period over which change was evaluated had a large impact on the magnitude of change detected and our conclusions regarding the ecological significance of those changes. Specifically, the cumulative impact on landscape structure was negligible over a 10-year period, but was notable over a 40-year period. In addition, the magnitude of change in landscape structure between 1950–1993 varied as a function of landscape extent. At the scale of the 228000 ha landscape, change in landscape structure was trivial, suggesting that the landscape was capable of fully incorporating the disturbances with minimal impact. However, at intermediate scales of 1000–10000 ha landscapes, change in landscape structure was quite evident, suggesting that there may be an optimal range of scales for detecting changes in landscape structure within the study area.     

How perceived sensory dimensions of urban green spaces affect cultural ecosystem benefits: A study on Haizhu Wetland Park,China

Research exploring the relationship between human well-being and ecosystem functions by assessing cultural ecosystem benefits (CEBs) is a crucial and emerging field. However, quantifying CEB is challenging due to the lack of a uniform measurement scale. In addition, it is crucial to understand the factors that influence CEBs to enhance ecosystem functions and contribute to human well-being. While physical landscape features have been investigated, there is limited evidence supporting the link between perception-based landscape features and CEBs. Therefore, this study aimed to develop a CEBs measurement scale and investigate the impact of perceived sensory dimensions (PSDs) of urban green spaces (UGSs) on CEBs. We conducted a Public Participation GIS-survey (PPGIS) at Guangzhou National Haizhu Wetland Park. 1473 participants took part in our study and evaluated the CEBs provided by urban green spaces (UGSs). Using SPSS statistics and ArcMap tools, we found that PSDs of UGSs are significantly associated with CEB. Additionally, we confirmed that different levels within a PSD influence the levels of CEBs gained from UGSs. Our results indicate that creating serene, open, and natural UGSs is more effective than incorporating numerous cultural elements. In conclusion, this study introduces PSDs into the framework of CEB, which landscape architects can use to shape the specific environmental characteristics of UGSs and provide the CEBs required to support the well-being of urban populations.     

The value of vegetation cover for ecosystem services in the suburban context

Latin-American cities can be characterized by dynamic processes of urbanization that encroach upon the natural and semi-natural surrounding landscapes. Our study presents the effects of landscape development, transformed from semi-natural conditions into a mostly disperse suburban settlement. We explore the impact that this transformation has had on this context by three ecosystem services that regulate rainwater runoff, enhance microclimate conditions and help to improve air quality by monitoring vegetation cover. We have designed a spatio-temporal hierarchical analysis which employs remote sensing techniques to capture the structural changes of this landscape over long, medium and short term scales on two spatial levels. This methodological approach was tested in the Metropolitan Area of Santiago (MAS) as case study area. Despite of the increase in impervious surfaces due to urban processes, there has also been an increase in vegetation cover, which has led to an improvement in the provision of the above-mentioned ecosystem services. Hence, if diverse urbanization processes continue and they are coupled with an increase in vegetation cover, the provision of ecosystem services could also expand. This phenomenon can be observed in some areas, where public and private green spaces are created and maintained. Our data analyses give evidence that certain types of suburban areas which increase the share of vegetation cover can provide daily ecological benefits for urban neighborhoods, and beyond, for adjacent areas. Moreover, suburban development can successfully provide ecological benefits to citizens. Such processes can only be ecologically sustainable if the composition of vegetation is well-adapted to the regional climatic conditions.