Baselines for land-use change in the tropics: application to avoided deforestation projects

Although forest conservation activities, particularly in the tropics, offer significant potential for mitigating carbon (C) emissions, these types of activities have faced obstacles in the policy arena caused by the difficulty in determining key elements of the project cycle, particularly the baseline. A baseline for forest conservation has two main components: the projected land-use change and the corresponding carbon stocks in applicable pools in vegetation and soil, with land-use change being the most difficult to address analytically. In this paper we focus on developing and comparing three models, ranging from relatively simple extrapolations of past trends in land use based on simple drivers such as population growth to more complex extrapolations of past trends using spatially explicit models of land-use change driven by biophysical and socioeconomic factors. The three models used for making baseline projections of tropical deforestation at the regional scale are: the Forest Area Change (FAC) model, the Land Use and Carbon Sequestration (LUCS) model, and the Geographical Modeling (GEOMOD) model. The models were used to project deforestation in six tropical regions that featured different ecological and socioeconomic conditions, population dynamics, and uses of the land: (1) northern Belize; (2) Santa Cruz State, Bolivia; (3) Paraná State, Brazil; (4) Campeche, Mexico; (5) Chiapas, Mexico; and (6) Michoacán, Mexico. A comparison of all model outputs across all six regions shows that each model produced quite different deforestation baselines. In general, the simplest FAC model, applied at the national administrative-unit scale, projected the highest amount of forest loss (four out of six regions) and the LUCS model the least amount of loss (four out of five regions). Based on simulations of GEOMOD, we found that readily observable physical and biological factors as well as distance to areas of past disturbance were each about twice as important as either sociological/demographic or economic/infrastructure factors (less observable) in explaining empirical land-use patterns. We propose from the lessons learned, a methodology comprised of three main steps and six tasks can be used to begin developing credible baselines. We also propose that the baselines be projected over a 10-year period because, although projections beyond 10 years are feasible, they are likely to be unrealistic for policy purposes. In the first step, an historic land-use change and deforestation estimate is made by determining the analytic domain (size of the region relative to the size of proposed project), obtaining historic data, analyzing candidate baseline drivers, and identifying three to four major drivers. In the second step, a baseline of where deforestation is likely to occur–a potential land-use change (PLUC) map—is produced using a spatial model such as GEOMOD that uses the key drivers from step one. Then rates of deforestation are projected over a 10-year baseline period based on one of the three models. Using the PLUC maps, projected rates of deforestation, and carbon stock estimates, baseline projections are developed that can be used for project GHG accounting and crediting purposes: The final step proposes that, at agreed interval (e.g., about 10 years), the baseline assumptions about baseline drivers be re-assessed. This step reviews the viability of the 10-year baseline in light of changes in one or more key baseline drivers (e.g., new roads, new communities, new protected area, etc.). The potential land-use change map and estimates of rates of deforestation could be re-done at the agreed interval, allowing the deforestation rates and changes in spatial drivers to be incorporated into a defense of the existing baseline, or the derivation of a new baseline projection.     

Effects of road age on the structure of roadside vegetation in south-eastern Australia

In many agricultural landscapes, roadside (or road verge) environments provide important refuge for threatened native species and ecosystems, and are often selected as benchmark sites to guide restoration activities. However few studies have investigated potential temporal variability in roadside vegetation conditions. In this paper we used archived cadastral maps to determine road age and examine potential variability in roadside vegetation structures in a typical rural landscape in south-eastern Australia. We found significant differences in the density of mature trees for road segments in different road-age categories. The oldest roads (<1870s) were characterized by having the greatest density of large hollow-bearing Eucalyptus trees, but few native conifer trees or shrubs. Roads surveyed when broad-scale clearing commenced (1870–1879), and not the oldest roads, were found to be more intact in terms of the density of large pre-settlement trees, range of tree stem-size classes and overall shrub diversity. By contrast, the youngest roads (post-1900s) had the greatest number of native conifer trees, but few shrubs or large Eucalyptus trees. As a result, roads of different ages had different densities of hollow-bearing trees, which is discussed in terms of past land-use legacies. These results have important implications for selecting roadsides as benchmark sites for restoration activities, and highlight the critical importance of roadsides to conserving native biota in agricultural landscapes.     

Diversity of cereal aphid parasitoids in simple and complex landscapes

Structurally complex landscapes may enhance local species richness and interactions, which is possibly due to a higher species pool in complex landscapes. This hypothesis was tested using cereal aphid parasitoids (Hymenoptera, Aphidiidae) by comparing 12 winter wheat fields in structurally complex landscapes (>50% semi-natural habitats; n = 6) and structurally simple landscapes dominated by agricultural lands (>80% arable land; n = 6). Surprisingly, landscape structural complexity had no effect on aphid parasitoid species diversity. In complex landscapes 12 and in simple landscapes 11 species were found; 9 species occurred in both landscape types. Hence, arable fields in high-intensity agricultural landscapes with little non-crop area can support a similar diversity of cereal aphid parasitoids as structurally complex landscapes. This finding suggests that cereal aphid parasitoids may find necessary resources even in simple landscapes, making generalisations concerning the relationship between landscape composition and biodiversity in arable fields difficult.     

Overstorey tree density and understorey regrowth effects on plant composition,stand structure and floristic richness in grazed temperate woodlands in eastern Australia

As natural woodlands decline in both extent and quality worldwide, there is an increasing recognition of the biodiversity conservation value of production landscapes. In low-input, low-productivity grazing systems in Australia, the modification of natural woodlands through overstorey tree and woody regrowth removal are vegetation management options used by landholders to increase native grass production for livestock grazing; however, there is little empirical evidence to indicate at what tree densities biodiversity attributes are compromised. We examined the effects of overstorey tree density and understorey regowth on the floristic composition, stand structure and species richness of eucalypt woodlands in a grazing landscape in the Traprock region of southern Queensland, Australia. We sampled 47 sites stratified according to vegetation type (Eucalyptus crebra/Eucalyptus dealbata woodland; Eucalyptus melliodora/Eucalyptus microcarpa grassy woodland), density of mature trees (<6 trees/ha; 6–20 trees/ha; >20 trees/ha), and presence/absence of regrowth. Distinct patterns in composition were detected using indicator species analysis and non-metric multidimensional scaling, with low density areas compositionally indistinguishable, although distinct from other land management units. Within vegetation type, medium tree density woodlands were compositionally similar to high density and reference woodlands. Species richness ranged from 18 to 67 species per 500 m² across all sites. No differences in total or native species richness were detected across management units; however, some differences in exotic species richness were detected. Differences in grass cover existed between low and high density management units, yet no difference in grass cover was evident between low and medium density management units. Our results suggest that medium tree densities may provide biodiversity benefits concordant with more natural areas, yet not adversely impact on pasture production. Retaining trees in grazing landscapes provides significant landscape heterogeneity and important refuges for species that may be largely excluded from open grassland habitats. Maintaining a medium density of overstorey trees in grazed paddocks can provide both production and biodiversity benefits.     

Carbon emissions from land-use change: an analysis of causal factors in Chiapas, Mexico

This study examines the correlation between deforestation, carbon dioxide emissions and potential causal factors of land-use change within an area of 2.7 million ha in Chiapas, southern Mexico between 1975 and 1996. Digitized land-use maps and interpreted satellite images were used to quantify land-use changes. Geo-referenced databases of population and digitized maps of roads and topography were used to determine which factors could be used to explain observed changes in land-use. The study analyzed the relationship between carbon emissions during this period and two types of possible causal factors: “predisposing” factors that determine the susceptibility of a particular area of forest to change (slope, distance to agriculture and roads, land tenure) and “driving” factors representing the pressures for change (population density, poverty). The correlated factors were combined in risk matrices, which show the proportion of vulnerable carbon stocks lost in areas with defined social, economic and environmental characteristics. Such matrices could be used to predict future deforestation rates and provide a verifiable evidence-base for defining baseline carbon emissions for forest conservation projects. Based on the results of the analysis, two matrices were constructed, using population density as the single most important driving factor and distance from roads and distance from agriculture as the two alternatives for the predisposing factors of deforestation.     

Multifunctional landscapes--perspectives for the future

New methods in landscape ecology to study the link between landscape between landscape heterogeneity and landscape functionality are needed.Heterogeneity is a basic characteristic of Iandscape,and landscape fnction is the capacity to change the structural heterogeneity of a landscape ystem.In most developed countries the industrialisation of agriculture has in general resulted in a change of agricultural landscapes from a small-grained heterogeneous pattern towards more monotonous and monofunctional landscapes.During the 1990‘s this trends seems to have changed due to a diversification of rural land use and new trends in urbanisation.Weather these phases of landscape development should be expected in developing countries is a totally open question.Dealing with the study of multifunctionality of landscapes it is proposed to distinguish between ecological functionality of landscape ecosystems,functionality.Further,the relation between function,space and scale is important by the determination of spatial and time segregation as well as spatial and time integration of multifunctionality in landscapes.     

How does agricultural intensification modulate changes in plant community composition?

Agricultural intensification, at local and landscape scales, has caused a decrease in plant diversity and changes in species composition in cereal fields. To better understand the role of landscape complexity and farming systems in shaping plant assemblages, it is of interest to focus on functional traits rather than on floristic composition, which may help to highlight trends in vegetation patterns. We analysed the relative abundance of various functional attributes (different life forms, growth forms, wind-pollinated species and wind-dispersed species) at three contrasted field positions (boundary, edge and centre) of 29 organic and 29 conventional cereal fields distributed in 15 agrarian localities of NE Spain. Agricultural intensification affected the biological attributes of the vegetation in dryland Mediterranean cereal fields; local factors (farming system and position) had a more prominent role in affecting plant functional composition than the surrounding landscape. Local factors were important for life form distribution, growth form and pollination type, whereas landscape complexity mainly affected the proportion of wind-dispersed species. Therefore, depending on the objective of the study, it is important to select functional attributes sensitive to the different scales of agricultural intensification, especially because landscape complexity and land-use intensity are commonly related.     

Delayed colonisation of arable fields by spring breeding ground beetles (Coleoptera: Carabidae) in landscapes with a high availability of hibernation sites

The colonisation of winter barley fields by spring breeding carabids and its temporal modulation by the amount of potential hibernation sites was studied. Species richness of carabids was lower in landscapes with high length of boundaries and a high amount of non-cropped open habitats during early stages of the beetles’ colonisation of arable fields. Species number of beetles with high dispersal potential responded to this landscape features at coarse spatial scales whereas beetles with low dispersal potential responded to intermediate scales. However, the negative impact of potential hibernation sites on colonisation diminished in later sampling phases. The patterns observed may be explained by both overwintering in arable soils in less complex landscapes and delayed colonisation in more complex landscapes. The seasonal patterns of landscape control suggest a need to account for temporal dynamics in interactions between species or functional groups and landscape properties. A high temporal resolution is needed in studies that focus on ecosystem function and services in agricultural landscapes, as direction of effect (positive/negative) of management on animal communities may change across spatial scales and within short time periods.     

A map-based method for exploring responses to different levels of grazing pressure at the landscape scale

At the beginning of the last century European landscapes were a mosaic of open and forested habitats formed by centuries of human use. During the 20th century, however, this mosaic was altered. Changes in grazing pressure from domestic animals have been suggested as one of the drivers of these alterations. This paper presents a methodology developed to calculate an index of potential grazing pressure change at the landscape level. Information about location, type and number of grazing animals is used to produce detailed Geographical Information System (GIS) maps of potential grazing pressure change. Spatial information from these maps can then be geographically linked to vegetation maps such that the effect of grazing pressure changes on vegetation can be statistically analyzed. This methodology was applied to a Norwegian mountain landscape to test if decreased grazing pressure by domestic animals leads to woodland establishment in open habitats. Canonical Correspondence Analyzes (CCA) were performed and the results showed significant effects. Decreased grazing pressure increased the probability of woodland establishment in heathlands. The methodology described in this paper might be a useful tool in planning strategies both for conservation efforts and sustainable resource use.     

The Satoyama Index: A biodiversity indicator for agricultural landscapes

Agricultural development to meet rapidly growing demands for food and biofuel and the abandonment of traditional land use have had major impacts on biodiversity. Habitat diversity is one of the most important factors influencing biodiversity in agricultural landscapes. In this study we propose an ecological index of ecosystem or habitat diversity in agricultural landscapes – the Satoyama Index (SI) – that is discernible under appropriate spatial units (e.g., 6 km × 6 km) from 1 km × 1 km gridded land-cover data available from an open-access web site. A high SI value is an indicator of high habitat diversity, which is characteristic of traditional agricultural systems, including Japanese satoyama landscapes, while a low value indicates a monotonic habitat condition typical of extensive monoculture landscapes. The index correlated well with the spatial patterns of occurrence of a bird of prey (Butastur indicus) and species richness of amphibians and damselflies in Japan. The values of the SI also corresponded well to the spatial patterns of typical traditional agricultural landscapes with high conservation value in other countries, for example, the dehesas of the Iberian Peninsula and shade coffee landscapes in Central America. Globally, the pattern of East/South-East Asian paddy belts with their high index values contrasts markedly with the low values of the Eurasian, American, and Australian wheat or corn belts. The SI, which correlates landscapes with biodiversity through potential habitat availability, is highly promising for assessing and monitoring the status of biodiversity irrespective of scale.     

云南澜沧江流域土地利用及其变化对景观生态风险的影响

利用GIS的空间分析功能,对云南澜沧江流域1980年、1992年和2000年3期TM遥感影像解译的土地利用解译数据进行图层代数运算,定量分析了土地利用变化及各种土地利用方式的相互转化关系;在土地利用变化的基础上,以景观干扰指数和土地利用类型的敏感度指数为评价指标,分析了不同研究时段内不同空间范围的景观生态风险变化情况.研究结果表明,自1992年以来该流域牛态环境受人类活动干扰增强,耕地、林地、草地三者之间相互转化频率较高;土地利用结构的变化已导致景观生态风险指数发生显著时空差异,中级以上的生态风险主要分布于该流域的中下游,分布范围呈东南向西北方向扩展,风险较高的地区增加幅度较大.受地形、地貌的影响,该区域的景观生态风险各向异性较显著,自相关范围在7.5km之内.澜沧江流域景观生态风险有扩大的趋势,应加强中级以上景观生态风险区域的生态保护与建设,以实现澜沧江流域的生态环境与社会经济的可持续发展.     

Farm-level models of spatial patterns of land use and land cover dynamics in the Ecuadorian Amazon

Longitudinal studies examining socio-demographic and other contextual factors are vital to understanding landscape change. Landscape structure, function, and change are assessed for the northern Ecuadorian Amazon by examining the composition and spatial organization of deforestation, agricultural extensification, and secondary plant succession at the farm level in 1990 and 1999 through the integration of data from a satellite time-series, a longitudinal household survey, and GIS coverages. Pattern metrics were calculated at the farm level through the generation of a hybrid land use and land cover (LULC) digital classification of Landsat Thematic Mapper (TM) data. Population, labor, and other household variables were generated from a scientific sample of survey farms or fincas interviewed in 1990 and resurveyed in 1999. Topography, soils, and distance and geographic accessibility measures were derived for sample farms through a GIS as well as qualitative assessments from household surveys. Generalized linear mixed models (GLMMs) were generated for 155 and 157 fincas in 1990 and 1999, respectively, using pattern metrics at the landscape level as dependent variables, and biophysical, geographical, and socio-economic/demographic variables as independent variables. The models were derived to explore the changing nature of LULC at the finca level by assessing the variation in the spatial structure or organization of farm landscapes in 1990 and 1999, and the extent to which this variation could be explained by the available data. Results indicate rapid population growth causing substantial subdivision of plots, which in turn has created a more complex and fragmented landscape in 1999 than in 1990. Key factors predicting landscape complexity are population size and composition, plot fragmentation through subdivision, expansion of the road and electrical networks, age of the plot (1990 only), and topography. The research demonstrates that the process of combining data from household surveys, satellite time-series images, and GIS coverages provide an ideal framework to examine population–environment interactions and that the statistical models presented are powerful tools to combine such data in an integrated way.     

Ecological restoration as a strategy for mitigating and adapting to climate change: lessons and challenges from Brazil

Climate change is a global phenomenon that affects biophysical systems and human well-being. The Paris Agreement of the United Nations Framework Convention on Climate Change entered into force in 2016 with the objective of strengthening the global response to climate change by keeping global temperature rise this century well below 2 °C above pre-industrial levels and to pursue efforts to limit the temperature increase even further to 1.5 °C. The agreement requires all Parties to submit their “nationally determined contributions” (NDCs) and to strengthen these efforts in the years ahead. Reducing carbon emissions from deforestation and forest degradation is an important strategy for mitigating climate change, particularly in developing countries with large forests. Extensive tropical forest loss and degradation have increased awareness at the international level of the need to undertake large-scale ecological restoration, highlighting the need to identify cases in which restoration strategies can contribute to mitigation and adaptation. Here we consider Brazil as a case study to evaluate the benefits and challenges of implementing large-scale restoration programs in developing countries. The Brazilian NDC included the target of restoring and reforesting 12 million hectares of forests for multiple uses by 2030. Restoration of native vegetation is one of the foundations of sustainable rural development in Brazil and should consider multiple purposes, from biodiversity and ecosystem services conservation to social and economic development. However, ecological restoration still presents substantial challenges for tropical and mega-diverse countries, including the need to develop plans that are technically and financially feasible, as well as public policies and monitoring instruments that can assess effectiveness. The planning, execution, and monitoring of restoration efforts strongly depend on the context and the diagnosis of the area with respect to reference ecosystems (e.g., forests, savannas, grasslands, wetlands). In addition, poor integration of climate change policies at the national and subnational levels and with other sectorial policies constrains the large-scale implementation of restoration programs. The case of Brazil shows that slowing deforestation is possible; however, this analysis highlights the need for increased national commitment and international support for actions that require large-scale transformations of the forest sector regarding ecosystem restoration efforts. Scaling up the ambitions and actions of the Paris Agreement implies the need for a global framework that recognizes landscape restoration as a cost-effective nature-based solution and that supports countries in addressing their remaining needs, challenges, and barriers.

     

20世纪80年代以来挠力河流域湿地景观变化过程研究

挠力河流域面积为241.67×104hm₂。其自然条件决定了该流域具有极丰富的湿地生物多样性。从1980年以来,由于经济的快速发展,该流域湿地景观和土地利用发生了显著的变化。自然湿地资源从1982年的53.32×104hm₂变成2000年的17.17×104hm₂,减少了67.8%;而水田面积却增加了38.5倍,同时,旱田面积也大幅度增加。该文利用遥感和GIS技术,对近20年来该流域湿地景观变化过程进行时空定量分析;并结合流域土地利用/土地覆盖类型的动态变化,探讨流域在经济快速发展中土地利用与湿地之间的演化规律及其对湿地的影响机制。     

Landscape protection as a tool for managing agricultural landscapes in Norway

Norwegian Protected Landscapes aim to preserve landscape character. As most of the agricultural land in Protected Landscapes is privately owned, the attitudes and behaviour of farmers are crucial in achieving this goal. We present results of a nationwide questionnaire to farmers who owned or managed farmland in Protected Landscapes. Thirty-eight percent of the respondents claimed that their farm business had been changed as a consequence of landscape protection. Niche products and alternative income possibilities, commonly forwarded as potential benefits of landscape protection status, had generally not been realised. Although we found that most farmers agreed on the importance of taking care of cultural landscapes, 76% felt that this was best done by using rather than protecting the landscape. The study revealed negative attitudes towards municipal authorities. A quarter of respondents were strongly against the establishment of new Protected Landscapes, even if they were compensated for economic losses. Based on results of the study we suggest that major improvements to the protection system could be made by improving communication between management authorities and farmers, and ensuring real involvement of farmers in making and carrying out management plans.     

Conserving invertebrate diversity in agricultural, forestry and natural ecosystems in Australia

Continental Australia and Tasmania cover a wide range of latitudes from tropical regions in the north through the arid and semi-arid core to cool temperature regions further south. Vegetation is equally varied and because of this and the continent's isolation during the Tertiary, floral and faunal diversity and endemism are very high. Europeans arrived 200 years ago and since that time have markedly modified the landscape by clearing and changing the vegetation, predominantly for agricultural and urban development. Both accidental and deliberate introductions of stock, weeds, crops, trees and pasture plants have also caused enormous changes to Australian environments. In the last few years the deleterious effects of some of these changes have been relaised, for example the extent of soil degradation. Measures are being taken to rectify problems and techniques are being introduced which benefit both primary producers and other users of the land and also nature conservation. Some of these measures for a more sustainable use of the land are illustrated here for four vegetation types, eucalypt woodland, native forests, grasslands and arid systems. They include adopting native tree species for timber production and native grasses for pasture, retention of native vegetation and paying attention to conservation of invertebrates in Parks and Reserves.     

南方丘陵山区典型地物景观特征尺度研究

景观的特征尺度反映了人与自然交互作用的空间过程,合理识别景观空间结构及其特征尺度有助于遥感影像景观空间异质性分析。论文以地处南方丘陵山区的福建省福州市为研究区,针对城市、农田、森林与水域4种地物景观,基于SPOT 10 m影像,分别利用半方差分析、小波分析与平均局部方差方法,开展景观特征尺度研究。结果表明:①不同景观类型的空间异质性差异较大,其中森林景观空间异质性最大,其次为城市、农田景观,水域的空间异质性最小;②小波方差分析和半方差分析分别检测到两个不同的特征尺度,而局部方差仅仅检测到较小的空间结构;③森林景观特征尺度比通常偏小,与南方丘陵山区破碎地形有关,城市景观更多体现为人类活动的影响,南方丘陵山区城市景观至少具有两种不同的空间结构,其特征尺度均较小,农田景观特征尺度最大。基于小波分析与半方差各自的特点,总结提炼出综合两种方法合理识别景观特征尺度的基本流程,即:首先开展小波分析,然后在此基础上利用半方差分析多种理论模型组合从而获得更详细的特征尺度信息,模型组合个数与参数初始值依据小波分析的结果而定。     

Woodland conservation in privately-owned cultural landscapes: the English experience

This paper reviews the development of approaches to the conservation of woodland on private lands in England since 1949. In England, the majority of woodland sites important for nature conservation are small, isolated amongst open habitats, with a long history of management. Conservation of wildlife has since 1949 had a strong focus on private lands. Two approaches to protection have been adopted. Firstly about 80,000 ha of English woods are within statutorily protected sites; the degree of protection for these has increased through successive legislation in 1949, 1981 and 2001. Secondly, since 1985 wildlife protection has been achieved on private lands outside the protected sites through general statutory forestry policies. There has also been an increasing trend for active promotion of voluntary nature conservation through forestry incentives and grants, and the setting of targets as part of the government’s biodiversity action plan. The variety of ways in which woodland may be protected (to differing degrees) in England has enabled effective protection to be achieved over a greater area of woodland than would have been possible through nature reserves alone. These approaches may be relevant in other countries where woodland occurs as part of a cultural landscape.     

Agricultural landscape change and stability in northeast Thailand: historical patch-level analysis

The temporal nature of agricultural landscape change, where both intra- and inter-annual processes and changes are often at work, renders traditional methods of landscape change assessment not completely effective. Additionally, seasonal and longer-term shifting patterns of cultivation can sometimes appear as permanent landscape change when in fact they actually are simply a local change in spatial arrangement. To address these complexities, this work tests an approach that is longitudinal in character and based upon assessing the structure of landscape change as well as the landuse/landcover (LULC) change. Set in rural northeast Thailand, patch dynamics are examined through use of LULC change trajectories built from an image time series and temporal patterns built from pattern metrics. The given unit of observation is the pixel, and its “life history” is constituted by the values derived from the images of a satellite time series, which are then reconstituted at the patch level for better ecological interpretation. The hypothesis that underpins this approach is that the nature of the trajectory is associated with the function of the land in that patch and in the neighborhood of surrounding patches. Hence, different trajectories of LULC spatial arrangement may suggest, for example, differences in the stability or dynamics of LULC over time and space, which are further suggestive of land sustainability or resilience, or conversely land conversion or dynamism. The study area for this research is a marginalized, agrarian environment in northeast Thailand, a region that has undergone deforestation of upland forests for the cultivation of commercial field crops, intensification of lowland rice for subsistence as well as local and regional sales and global export, and LULC scenarios altering the savanna landscape that serves as the background matrix. The analysis here characterizes the relative stability and temporal dynamics of LULC at the patch level. Pattern metrics calculated at the patch level are assessed as the spatial organization of landscape units that represent: (1) transitional areas of LULC dynamics occurring as peripheral expansion, (2) LULC change from forest to agriculture through deforestation, or (3) agriculture to forest through secondary plant succession, with savanna serving as a transitional matrix. In short, this paper proposes and tests a method for assessing the temporal persistence of LULC through pattern metrics. The method contributes a technique for analyzing the landscape ecology of sites as a function of their stability/dynamics within a scale-explicit context, and contributes to the growing body of work on relating scale, pattern, and process.