Modelling carbon storage in highly fragmented and human-dominated landscapes: Linking land-cover patterns and ecosystem models

To extend coupled human–environment systems research and include the ecological effects of land-use and land-cover change and policy scenarios, we present an analysis of the effects of forest patch size and shape and landscape pattern on carbon storage estimated by BIOME-BGC. We evaluate the effects of including within-patch and landscape-scale heterogeneity in air temperature on carbon estimates using two modelling experiments. In the first, we combine fieldwork, spatial analysis, and BIOME-BGC at a 15-m resolution to estimate carbon storage in the highly fragmented and human-dominated landscape of Southeastern Michigan, USA. In the second, we perform the same analysis on 12 hypothetical landscapes that differ only in their degree of fragmentation. For each experiment we conduct four air-temperature treatments, three guided by field-based data and one empirically informed by local National Weather Service station data. The three field data sets were measured (1) exterior to a forest patch, (2) from the patch edge inward to 60 m on east-, south-, and west-facing aspects, separately, and (3) interior to that forest patch. Our field-data analysis revealed a decrease in maximum air temperature from the forest patch edge to a depth of 80 m. Within-patch air-temperature values were significantly different (α = 0.01) among transects (c.v. = 13.28) and for all measurement locations (c.v. = 30.58). Results from the first experiment showed that the interior treatment underestimated carbon storage by ～8000 Mg C and the exterior treatment overestimated carbon storage by 30,000 Mg C within Dundee Township, Southeastern Michigan, when compared to a treatment that included within-patch heterogeneity. In the second experiment we found a logarithmic increase in carbon storage with increasing fragmentation (r² = 0.91). While a number of other processes (e.g. altered disturbance frequency or severity) remain to be included in future experiments, this combined field and modelling study clearly demonstrated that the inclusion of within-patch and landscape heterogeneity, and landscape fragmentation, each have a strong effect on forest carbon cycling and storage as simulated by a widely used ecosystem process model.     

Long-term forest management and timely transfer of carbon into wood products help reduce atmospheric carbon

In their efforts to deal with global climate change, scientists and governments have given much attention to the carbon emissions associated with fossil fuels and to strategies for reducing their use. While it is very important to burn less fossil fuel and to employ alternative energy sources, other carbon-reduction options must also be considered. Given that forests comprise a large portion of the global landbase and that they play a very significant role in the global carbon cycle, it is logical to examine how forest management practices could effect reductions in carbon emissions. Many papers that discuss forest carbon sinks or sources refer only to the short term (<20 years). This paper focuses on the sustainable carbon storage contributions of a forest over the long term. This paper explains that long-term carbon storage and reduced carbon fluctuation can be achieved by a combination of improved forest management and efficient transfer of carbon into wood products. Here we show how three different forest management scenarios affect the overall carbon storage capacity of forest and wood products combined over the long term. We used a timber supply model and scenario analysis to predict forest carbon and other resource conditions over time in the Prince George Forest District, a 3.4-million-ha landbase in northern British Columbia. We found that the high-harvest scenario stores 3% more carbon than the low-harvest scenario and 27% (120 million tonnes) more carbon than the no-harvest scenario even though only 1.2-million ha is in timber harvesting landbase. Our results tell us that forest management practices that maintain and increase forest area, reduce natural disturbances in the forest, improve forest conditions, and ensure the appropriate and timely transfer of carbon into wood products lead to increasing overall carbon storage, thereby reducing carbon in the atmosphere.     

LANDIS and forest landscape models

This paper provides contextual documentation of the LANDIS model development to provide a framework for the other papers in this special issue. The LANDIS model of forest landscape disturbance and succession was developed since the early 1990s as a research and management tool that optimizes the possible landscape extent (100 s ha to 1000 s km²), while providing mechanistic detail adequate for a broad range of potential problems. LANDIS is a raster model, and operates on landscapes mapped as cells, containing tree species age classes. Spatial processes, such as seed dispersal, and disturbances such as fire, wind, and harvesting can occur. LANDIS development benefited from the modelling and research progress of the 1960s to the1980s, including the growth of landscape ecology during the 1980s. In the past decade the model has been used by colleagues across North America, as well as in Europe and China. This has been useful to those not able to undertake the cost and effort of developing their own model, and it has provided a growing diverse set of test landscapes for the model. These areas include temperate, southern, and boreal forests of eastern North America, to montane and boreal western forests, coastal California forest and shrub systems, boreal Finnish forests, and montane forests in Switzerland and northeastern China. The LANDIS model continues to be refined and developed. Papers in this special issue document recent work. Future goals include integration within a larger land use change model, and applications to landscape and regional global change projection based on newly incorporated biomass and carbon dynamics.     

A simplified approach to implement forest eco-hydrological properties in regional hydrological modelling

The topic of this paper is a simplified model for simulating the hydrological properties of forest stands based on a robust computation of the temporal LAI (leaf area index) dynamics. The approach allows the simulation of all hydrologically relevant processes. It includes interception of precipitation and transpiration of forest stands with and without groundwater in the rooting zone. The model also considers phenology, mortality and simple management practice. It was implemented as a module in the eco-hydrological model SWIM (Soil and Water Integrated Model). The approach was tested on Scots pine (Pinus sylvestris) and common oak (Quercus robur and Q. petraea).The results demonstrate a good simulation of annual biomass increase and LAI and satisfactory simulation of litter production (annual mean value). A comparison of the date of May sprout for Scots pine and leaf unfolding for Oak (1980–1990) with observed data of the DWD (German Weather Service) shows a good reproduction of the temporal dynamic. The daily simulation of transpiration shows an excellent correlation of r = 0.81 for the year 1998 but only r = 0.65 for 1999. The interception losses were also simulated and compared with weekly observed data showing satisfactory results in the vegetation periods and annual sums, but worse agreement in autumn and spring time. A regional assessment study was done in the federal state of Brandenburg (Germany) to test the applicability and multi-criteria evaluation capabilities of the approach on the landscape and catchments scale using forest data, daily river discharge and regional water balance.     

Contribution of Roads to Forest Fragmentation in the Rocky Mountains

The contribution of roads to forest fragmentation has not been adequately analyzed. We quantified fragmentation due to roads in a 30,213-ha section of the Medicine Bow-Routt National Forest in sout heastern Wyoming with several indices of landscape structure using a geographic information system. The number of patches, mean patch area, mean interior area, mean area of edge influence, mean patch perimeter, total perimeter, and mean patch shape identified patch- and edge-related landscape changes. Shannon-Wiener diversity, dominance, contagion, contrast, and angular second moment indicated effects on landscape diversity and texture. Roads added to forest fragmentation more than clearcuts by dissecting large patches into smaller pieces and by converting forest interior habitat into edge habitat. Edge habitat created by roads was 1.54–1.98 times the edge habitat created by clearcuts. The total landscape area affected by clearcuts and roads was 2.5–3.5 times the actual area occupied by these disturbances. Fragmentation due to roads could be minimized if road construction is minimized or rerouted so that its fragmentation effects are reduced. Geographic information system technology can be used to quantify the potential fragmentation effects of individual roads and the cumulative effects of a road network on landscape structure.     

Forest age structure as indicator of boreal forest sustainability under alternative management and fire regimes: A landscape level sensitivity analysis

Effective forest ecosystem-based management requires a thorough understanding of the interactions between anthropogenic and natural disturbance processes over larger spatial and temporal scales than stands and rotation ages. Because harvesting does not preclude fire, it is important to evaluate the combined effects of harvesting and fire on forest age structure, a coarse indicator of forest ecosystem state. We performed a sensitivity analysis of landscape scale effects of forest management (strategy, harvest rate and access cost) and fire regime (fire return interval and extent) in terms of combined impacts on forest stand age-class structure on a study area of 3.5 million hectares of boreal forest of Québec. A series of scenarios were simulated over 500 years and replicated 30 times using a previously reported spatially explicit landscape model. Within the parameter space of our sensitivity analysis, we found that harvest rate, fire return interval and management strategy were the most significant parameters affecting stand age-class distribution across the landscape. The former are not so surprising, given that they combine to produce an overall disturbance rate, but the latter shows that the resulting impact on age-class structure can be influenced to some degree through management objectives. A harvesting strategy of clearcutting for sustained timber supply, using a harvest rotation based on minimum merchantable age (approximately 100 years in this analysis), creates a trend for the stand age-class distribution away from the expected range of natural variation for the study area. Within the scope of our simulations, alternative management strategies with extended harvest rotation age proved the most robust forest management practice to absorb variations in fire regime.     

The effects of forest harvest intensity in combination with wind disturbance on carbon dynamics in Lake States Mesic Forests

Total forest carbon (C) storage is determined by succession, disturbances, climate, and the edaphic properties of a site or region. Forest harvesting substantially affects C dynamics; these effects may be amplified if forest harvesting is intensified to provide biofuel feedstock. We tested the effects of harvest intensity on landscape C using a simulation modeling approach that included C dynamics, multiple disturbances, and successional changes in composition. We developed a new extension for the LANDIS-II forest landscape disturbance and succession model that incorporates belowground soil C dynamics derived from the CENTURY soil model. The extension was parameterized and calibrated using data from an experimental forest in northeastern Wisconsin, USA. We simulated a 9800 ha forested landscape over 400 years with wind disturbance combined with no harvesting, harvesting with residual slash left on site (‘standard harvest’), and whole-tree harvesting. We also simulated landscapes without wind disturbance and without eastern hemlock (Tsuga canadensis) to examine the effects of detrital quantity and quality on C dynamics. We estimated changes in live C, detrital C, soil organic C, total C, and forest composition. Overall, the simulations without harvesting had substantially greater total C and continued to sequester C. Standard harvest simulations had more C than the whole tree harvest simulations. Under both harvest regimes, C accrual was not evident after 150 years. Without hemlock, SOC was reduced due to a decline in detritus and a shift in detrital chemistry. In conclusion, if the intensity of harvesting increases we can expect a corresponding reduction in potential C storage. Compositional changes due to historic circumstances (loss of hemlock) may also affect forest C although to a lesser degree than harvesting. The modeling approach presented enabled us to consider multiple, interacting drivers of landscape change and the subsequent changes in forest C.     

Population growth versus population spread of an ant-dispersed neotropical herb with a mixed reproductive strategy

In plants that produce seeds with contrasting genetic background (selfed versus outcrossed), the question arises whether the ecological function of the two types of progeny differ. This paper addresses this issue for the ant-dispersed Calathea micans by introducing a novel application of the Neubert–Caswell model for analysis of wave speed for structured populations. Because dispersal as well as vital rates are structured, the model allows for distinct dispersal kernels for different types of progeny and thus permits comparisons of the sensitivity to changes in demographic and dispersal parameters of in situ population growth rate versus population spread across space. The study site was a lowland, evergreen tropical rain forest at La Selva Biological station, Costa Rica, where the species is commonly found throughout the forest. In C. micans, seeds produced by open flowers (potentially outcrossed) or by closed flowers (selfed) bear oily arils and are dispersed by ants. Five life-history stages were used to characterize the population: seedlings originating from seeds produced by open flowers, seedlings originating from seeds produced by closed flowers, juvenile vegetative plants, reproductive plants without new shoots and reproductive plants with new shoots. Demography varied seasonally. Transitions were estimated from marking and following the fate of plants (N = 400) in a natural population over a dry and a wet season. The population dynamics was described by a 10 × 10 matrix, with five life-history stages and two habitat states. The habitat states cycle repeatedly, dry–wet–dry–wet. To estimate dispersal kernels for each seed type, individual seeds (N = 225 and 306 seeds produced by open and closed flowers, respectively) were color-coded and placed in depots, allowing the ants to redistribute them. Five months later, seedlings with an attached seed coat bearing the intact color-coding, were surveyed around the depots. Radial distances and angles were recorded for each seedling (N = 67 and 81 seedlings arising from open and closed flowers, respectively). The results of the model give an asymptotic growth rate of 1.06 per season and an asymptotic rate of spread of 8.36 cm per season. There is a high correlation (r = 0.99) between elasticity of growth rate and elasticity of rate of spread of the population. Both rates are most sensitive to changes in stasis of juveniles during the dry season. However, most interesting is the analysis that revealed that population spread is more sensitive than in situ population growth to demographic rates of seedlings arising from open flowers. The analysis suggests a new way of thinking about ecological functions of multiple modes of reproduction.     

Modeled carbon sequestration variation in a linked erosion–deposition system

Unraveling the consequences of hydrologic transport on carbon (C) storage will help identify feedbacks between land management alternatives, climate change, and soil-vegetation-atmospheric-transfers (SVATs) of C. There is a need for theoretically driven models of erosion and deposition that includes transport induced mineralization to better understand the controls on SVATs of C. Here we present a model developed using a systems-dynamic approach that coupled C-SVATs at a 2-day resolution with a discrete event erosion–deposition model occurring with a prescribed return interval. Five possible mass-balance transformations of C occurring between the two patches were explicitly modeled: net primary production (NPP), decomposition, erosion, transport induced mineralization, and deposition. The net C-SVAT, NPP minus decomposition, exhibited three stable points of no net C flux. Starting with arbitrary initial C pool in each patch above the bifurcation point, the model approached a quasi-steady state, which included both the short-term and longer term consequences of erosion; in the baseline simulation 5080 g C m⁻² was stored prior to erosion and 100 years of low intensity erosion 4840 g C m⁻² SOC remained. Low intensity erosion also generated spatial heterogeneity; from an initial homogeneous distribution to 40% of the C stored in the eroded patch and 60% of the C stored in the deposition patch. Erosion reduction resulted in a corresponding increase in total soil C content that was positively related to the magnitude of erosion reduction. In conjunction with providing a modeling framework for reducing the uncertainty in C-SVAT, this model is a prototype of a growing theory of ecosystem processes within spatially explicit landscapes, a meta-ecosystem model.     

Quantifying spatial structure of volumetric neutral models

Neutral models in landscape ecology that have been used as a framework to analyze actual landscapes have been largely planar. However, the natural world is greater than two dimensions; hence, many ecological structures, e.g., forest canopies or coral reefs, are better represented by topographies or tomographies. Because pattern and process or structure and function are intertwined, it becomes necessary to develop methods to quantify these complex architectures. With the advent of remote sensing technologies such as lidars and sonars, that permit structural mapping of some of these systems, volumetric data are becoming more prevalent. In this study, we developed a suite of binary voxel-based neutral models that possessed random, anisotropic, and hierarchical properties. We then evaluated the extent to which fractal-derived measurements, i.e., lacunarity, the simple fractal dimension, and multifractal spectra, were able to discern among the constructed model types at two different densities (p = 0.02 and p = 0.05). Multifractal analysis, where spectra were defined by three parameters, was shown to be the most sensitive to the differences among the neutral structures. Lacunarity, defined by a single parameter, was shown to be fairly useful in discerning the structures. The simple fractal dimension was found to have limited capability. To more fully assess the ability of these and additional pattern recognition methods, better representations of natural morphologies need to be developed and analyzed.     

Applying Principles of Landscape Design and Management to Integrate Old-Growth Forest Enhancement and Commodity Use

Using geographic information systems (GIS) and spatial analysis techniques, we developed a landscape design to maintain old-growth forest remnants and integrate commodity production in the surrounding second-growth matrix. The 4500-ha forest landscape in northern Wisconsin contains scattered patches of old-growth eastern hemlock ( Tsuga canadensis ) and northern hardwoods, predominately sugar maple ( Acer saccharum ). The design incorporates an old-growth restoration zone surrounding old-growth patches to buffer and enhance forest-interior habitat and link nearby old-growth remnants. This addition restores aspects of landscape patch size and structure and ecosystem juxtaposition that characterize a nearby, large, and contiguous natural old-growth landscape. A larger secondary zone is delineated for uneven-aged forest management. This zone provides a matrix structurally similar to the old-growth patches but also accommodates harvesting. A larger outer zone is retained primarily in even-aged forest of aspen ( Populus tremuloides ) and paper birch ( Betula papyrifera ), but traditional clearcutting practices are modified to partial cutting and mixed-species rotations. This design meets limited goals of biodiversity enhancement and integrated commodity production in a landscape that will remain largely harvested. The landscape design is therefore improved not only by buffers and corridors provided to old-growth ecosystems, but by modifying the management of the majority commodity lands matrix as well.     

黑龙江省森林景观的格局变化

运用地理信息系统分析软件ARC／INFO 8．01、ARCVIEW 3．2和基于ARC／INFO的FRAGSTATS 3．0软件，处理了1896年、1949年和1981年黑龙江省森林资源分布图，并用所得到的斑块总面积、平均斑块大小、斑块密度、斑块大小变异系数、平均斑块分数维和平均形状指数对黑龙江省森林景观格局变化和各个斑块类型的变化进行了研究．结果表明，从1896年到1981年黑龙江省森林景观的总面积急剧减少，斑块数量增多，斑块密度加大，平均斑块大小减少，斑块间的毗连程度减弱，但是斑块的形状逐渐趋于相对规则，斑块的边界趋于简单化，所有这些表明，森林景观逐渐趋于破碎化，其中以红松的破碎化最为严重．整个森林的景观多样性和景观类型分布的均匀性逐渐降低．造成这一变化的主要原因是人类的经济活动，另一原因是近一个世纪的气候变化及森林群落的自身演替，但是同人类的干扰作用相比，作用很微弱．图5表2参19     

Use of Riparian Buffer Strips as Movement Corridors by Forest Birds

We conducted a 3-year field experiment to measure the frequency of bird movements through riparian buffer strips before and after harvesting of adjacent forest. Our study was conducted in the boreal mixed wood forest of Alberta and was designed to determine empirically whether songbirds use riparian buffer strips of forest connecting forest reserves as corridors and if they move along these buffer strips more frequently than they cross adjacent clearcuts. We used mist nets to obtain an index of the frequency of bird movement in the forest, and we observed bird movements across adjacent clearcuts for comparison. We predicted that the frequency of movement would be greater (1) in buffer strips after harvesting of adjacent forest than before harvesting, (2) in buffer strips than across clearcuts and, (3) in buffer strips than at control sites (lakeshore forest with no adjacent clearcuts). After adjusting for year-to-year variation in abundance, we found that capture rates increased significantly from pre- to post-harvest, but only for juveniles. Capture rates of adults decreased immediately after harvesting, probably because of the removal of an adjacent source of birds that previously moved through the lakeside forest. Movement rates of forest species in clearcuts were significantly lower than capture rates in the forest. The number of adults captured was positively correlated with the number of territories in the buffer strips, indicating that most birds captured were probably residents. The number of local territories was a poor predictor of juvenile captures, supporting the notion that juveniles were likely dispersing individuals. Our results indicate that buffer strips enhanced movements of juveniles (i.e., acted as corridors) and maintained movement rates of adults. Furthermore, there appeared to be a threshold distance between reserves below which birds may be less reluctant to fly across openings, making corridor use less important.     

Modelling the spatial distribution of montane and subalpine forests in the central Alps using digital elevation models

The analysis of complex interactions between spatial distribution patterns of site factors and vegetation types is crucial for understanding high mountain ecosystems, especially in the view of a changing climate. Therefore, in the present study, a GIS and remote sensing-based approach is followed to produce a vegetation map for a study area in the Western Alps (Switzerland). Two major forest alliances are chosen for analysis: subalpine coniferous forest Vaccinio-Piceion/Larici-Pinetum cembrae and montane oak forest Quercion pubescenti-petraeae. As spatial information on site factors is commonly lacking in mountain areas, the use of a digital elevation model (DEM) is a potential substitute for use in vegetation analyses: it highly correlates with temperature, moisture, geomorphological processes and disturbance factors. Thus, it is important to analyse the capabilities of a DEM for indicating habitat conditions in a landscape characterised by high topodiversity and a patchwork of microclimatic habitats.For the purpose of identifying the potential of landform parameters for the indication of forest habitat structures in the present study, 24 primary and secondary landform parameters have been derived, indicating temperature and moisture distribution, exposure towards wind, snow, etc. Quantitative analyses were performed using statistical means such as contingency correlation coefficients and principal components analysis. The results formed the basis for the development of parallel-epiped-vegetation models (PED) used to simulate the spatial distribution patterns of the subalpine coniferous and the montane oak forest. It can be shown that topographic variables derived from a DEM at a spatial resolution of 25 m are very useful for indicating habitats of large forest types. Additionally potential forest sites in the cultural landscape, removed by human logging, can be reconstructed.Inaccuracies within the simulation results can partly be attributed to the insufficient parameterisation of geomorphologic activity and to poor spatial resolution of the DEM as compared to the vegetation data. Although the lack of information on the human dimension leads to some uncertainties in the interpretation of spatial patterns of vegetation, the exclusive use of topographic variables in vegetation models for the indication of forest habitats is very promising.     

滇池流域土地利用景观空间格局对水质的影响

选用综合水质评价方法,对滇池流域进行水质评价。选取斑块数量（NP）、斑块密度（PD）、最大斑块指数（LPI）、最大形状指数（LSI）,作为表征景观空间格局的参数,来分析流域优势斑块对水质的影响。对水质评价结果与景观指数进行相关性分析得出：居民点及工矿用地斑块数量越多、形状越不规则,有利于延缓水质状况的恶化;耕地斑块越大,越集中,本身产生的面源污染浓度就越高,而流经耕地的径流中的污染物浓度则会因大斑块的吸附过滤作用而降低;林地斑块密度越大,对污染物的截留纳污作用就越大,而斑块越大,可能产生局限性,导致未流经林地的污染物直接进入河流而影响水质。     

Fire and forest landscapes in the Georgia Piedmont: an assessment of spatial modeling assumptions

Landscape simulation models are widely used to study the behavior of ecological systems. As computing power has increased, these models have become more complex and incorporated more realistic spatial representations of landscape patterns and ecological processes. The goal of this research was to examine the sensitivity of simulated landscape patterns to fundamental spatial modeling assumptions. The LANDIS simulator was parameterized for forests of the Georgia Piedmont and used to model landscape-scale community dynamics at fire return intervals from 20 to 100 years. A base scenario incorporating localized seed dispersal along with landform-related variation in species establishment rates and disturbance regimes was contrasted with three alternative scenarios. The uniform habitat scenario applied the same set of species establishment coefficients across all landforms. The uniform dispersal scenario removed the effects of seed source abundance and pattern on species establishment. The uniform disturbance scenario assumed identical disturbance regimes on all landforms.At the shortest fire return intervals, fire severities were low and the stand age distribution was dominated by older forests. At longer fire return intervals, fire severities were high and the stand age distribution was skewed toward younger forests. Species composition generally followed a gradient from fire-resistant species at short fire return intervals to fire-sensitive species at longer fire return intervals. However, some species exhibited bimodal distributions with high abundances at both short and long fire return intervals. Landscape responses to fire were similar in the uniform habitat scenario and the base scenario. Communities were less sensitive to fire return interval and had more fire-sensitive species in the uniform dispersal scenario than in the base scenario. Species composition in the uniform disturbance scenario was similar to the base scenario for the longest fire-intervals, but was more sensitive to changes in the fire regime at shorter fire return intervals. In models of Piedmont forest landscapes, accurate spatial representations of dispersal and fire regime heterogeneity are essential for predicting landscape-scale species composition under changing fire regimes. In contrast, the precise spatial representation of species–habitat relationships may be considerably less important.     

A peaked function for modeling temperature dependence of plant productivity

We suggests that temperature response of plant productivity can be modeled by the Arrhenius function modified to describe the effect of temperature on enzyme activity: G_A(T) = 2f(T)/(1 + f²(T)), where f(T) = exp(E_a/RT_opt − E_a/RT), R the universal gas constant, E_a the activation energy and T_opt is the optimal temperature. In common with other functions used for modeling the temperature response of plant productivity, the curve of function G is almost symmetrical and bell-shaped. The special convenience of G_A is that it relates the width of the “bell” to thermodynamic concepts, such as activation energy of chemical reactions converting carbon dioxide and water to carbohydrates.     

Habitat fragmentation affects movement behavior of migrating juvenile common toads

Displacement characteristics in animals are crucial drivers of successful movement decisions in resources acquisition, migration, and dispersal. As landscape structure is modified by human activity, mobility patterns are likely to evolve in response to habitat fragmentation. In species with complex life cycles that involve obligatory migrations between different habitats, one can predict that movement propensity would be promoted by fragmentation as long as it allows to reaching a habitat patch. Here, we compare the movement characteristics of naive toadlets sampled in populations distributed over a fragmentation gradient to test the hypothesis of a positive correlation between fragmentation and mobility levels. We studied toadlet movement in experimental arenas providing small patches of suitable conditions. We recorded the use of these patches (patch behavior) or the absence of their use (overtaking behavior). The more fragmented the original landscape, the more prone the toadlets were to combine these two behaviors, thus showing a higher motivation to explore. Moreover, the more fragmented the original landscape, the less the toadlets exhibited patch behavior. As the toadlets were reared in a common environment, the behavioral differences detected, relating to the level of fragmentation, resulted from inheritance. Our results thus illustrate that fragmentation is likely to create cross-generational transmittable variations in movement characteristics.     

Urban forest landscape patterns in Ma'anshan City,China

The landscape pattern of Ma'anshan City was analyzed based on theories and methodologies of landscape ecology, remote sensing, global positioning, and a geographic information system (GIS). The study area encompassed the entire built-up area of 63.88 km²; a north–south transect 3-km wide and 13-km long was established along the long axis of the city. Five major landscape elements were assessed: urban land, urban forest, agriculture, water, and grass. Urban land was the dominant land cover type, and occupied 67% of total land area; while patches of urban forest occupied 16%, with a landscape element dominance of 0.42. Urban forest was classified according to land-use category and location into six types: scenic forest, yard forest, recreational forest, roadside forest, shelter forest, and nurseries. There were 2464 urban forest patches, the largest being 185.1 ha, with an average of 0.43 ha. The low nearest neighbor index and high patch density indicated that urban forest patches tend to be aggregated and have a high degree of fragmentation. This study also demonstrated that the spatial pattern of urbanization could be quantified using a combination of landscape metrics and gradient analysis. Urban forest has distinct spatial characters that are dependent on specific landscape metrics along the urbanization gradient.