Jane Southworth

An Exploratory Framework for the Empirical Measurement of Resilience

Deliberate progress towards the goal of long-term sustainability depends on understanding the dynamics of linked social and ecological systems. The concept of social-ecological resilience holds promise for interdisciplinary syntheses. Resilience is a multifaceted concept that as yet has not been directly operationalized, particularly in systems for which our ignorance is such that detailed, parameter-rich simulation models are difficult to develop. We present an exploratory framework as a step towards the operationalization of resilience for empirical studies. We equate resilience with the ability of a system to maintain its identity, where system identity is defined as a property of key components and relationships (networks) and their continuity through space and time. Innovation and memory are also fundamental to understanding identity and resilience. By parsing our systems into the elements that we subjectively consider essential to identity, we obtain a small set of specific focal variables that reflect changes in identity. By assessing the potential for changes in identity under specified drivers and perturbations, in combination with a scenario-based approach to considering alternative futures, we obtain a surrogate measure of the current resilience of our study system as the likelihood of a change in system identity under clearly specified conditions, assumptions, drivers and perturbations. Although the details of individual case studies differ, the concept of identity provides a level of generality that can be used to compare measure of resilience across cases. Our approach will also yield insights into the mechanisms of change and the potential consequences of different policy and management decisions, providing a level of decision support for each case study area.

Consequences of future climate change and changing climate variability on maize yields in the midwestern United States

Any change in climate will have implications for climate-sensitive systems such as agriculture, forestry, and some other natural resources. With respect to agriculture, changes in solar radiation, temperature, and precipitation will produce changes in crop yields, crop mix, cropping systems, scheduling of field operations, grain moisture content at harvest, and hence, on the economics of agriculture including changes in farm profitability. Such issues are addressed for 10 representative agricultural areas across the midwestern Great Lakes region, a five-state area including Indiana, Illinois, Ohio, Michigan, and Wisconsin. This region is one of the most productive and important agricultural regions in the world, with over 61% of the land use devoted to agriculture. Individual crop growth processes are affected differently by climate change. A seasonal rise in temperature will increase the developmental rate of the crop, resulting in an earlier harvest. Heat stress may result in negative effects on crop production. Conversely, increased rainfall in drier areas may allow the photosynthetic rate of the crop to increase, resulting in higher yields. Properly validated crop simulation models can be used to combine the environmental effects on crop physiological processes and to evaluate the consequences of such influences. With existing hybrids, an overall pattern of decreasing crop production under scenarios of climate change was found, due primarily to intense heat during the main growth period. However, the results changed with the hybrid of maize (Zea mays L.) being grown and the specific location in the study region. In general, crops grown in sites in northern states had increased yields under climate change, with those grown in sites in the southern states of the region having decreased yields under climate change. Yields from long-season maize increased significantly in the northern part of the study region under future climate change. Across the study region, long-season maize performed most successfully under future climate scenarios compared to current yields, followed by medium-season and then short-season varieties. This analysis highlights the spatial variability of crop responses to changed environmental conditions. In addition, scenarios of increased climate variability produced diverse yields on a year-to-year basis and had increased risk of a low yield. Results indicate that potential future adaptations to climate change for maize yields would require either increased tolerance of maximum summer temperatures in existing maize varieties or a change in the maize varieties grown.

Remotely Sensed Spectral Heterogeneity As a Proxy of Species Diversity: Recent Advances and Open Challenges

Abstract Environmental heterogeneity is considered to be one of the main factors associated with biodiversity given that areas with highly heterogeneous environments can host more species due to their higher number of available niches. In this view, spatial variability extracted from remotely sensed images has been used as a proxy of species diversity, as these data provide an inexpensive means of deriving environmental information for large areas in a consistent and regular manner. The aim of this review is to provide an overview of the state of the art in the use of spectral heterogeneity for estimating species diversity. We will examine a number of issues related to this theme, dealing with: i) the main sensors used for biodiversity monitoring, ii) scale matching problems between remotely sensed and field diversity data, iii) spectral heterogeneity measurement techniques, iv) types of species taxonomic diversity measures and how they influence the relationship between spectral and species diversity, v) spectral versus genetic diversity, and vi) modeling procedures for relating spectral and species diversity. Our review suggests that remotely sensed spectral heterogeneity information provides a crucial baseline for rapid estimation or prediction of biodiversity attributes and hotspots in space and time.

Accessibility as a determinant of landscape transformation in western Honduras: linking pattern and process

This study evaluates the relationship between landscape accessibility and land cover change in Western Honduras, and demonstrates how these relationships are influenced by social and economic processes of land use change in the region. The study area presents a complex mosaic of land cover change processes that involve approximately equal amounts of reforestation and deforestation. Landsat Thematic Mapper (TM) satellite imagery of 1987, 1991 and 1996 was used to create three single date classifications and a land cover change image depicting the sequence of changes in land cover between 1987–1991–1996. An accessibility analysis examined land cover change and landscape fragmentation relative to elevation and distance from roads. Between 1987 and 1991, results follow ‘expected’ trends, with more accessible areas experiencing greater deforestation and fragmentation. Between 1991 and 1996 this trend reverses. Increased deforestation is found in areas distant from roads, and at higher elevations; a result of government policies promoting expansion of mountain coffee production for export. A ban on logging, and abandonment of marginally productive agricultural fields due to agricultural intensification in other parts of the landscape, has led to increased regrowth in accessible regions of the landscape. Roads and elevation also present different obstacles in terms of their accessibility, with the smallest patches of cyclical clearing and regrowth, relating mostly to the agricultural fallow cycle, found at the highest elevations but located close to roads. This research highlights the need to locate analyses of land cover change within the context of local socio-economic policies and land use processes.

The Influence of Accessibility, Local Institutions, and Socioeconomic Factors on Forest Cover Change in the Mountains of Western Honduras

Abstract Tropical deforestation poses a threat to ecological sustainability and socioeconomic development in many parts of the world. Information on forest transformations is especially pertinent in sensitive ecological zones such as mountainous regions, where forest cover protects steep slopes and thin soils from erosion. Such areas are frequently unsuitable for agriculture, but inhabitants may have few alternatives to meet subsistence needs. Understanding the relationship between human behavior and forest change poses a major challenge for development projects, policy makers, and environmental organizations that aim to improve forest management. Knowledge of the areal extent of forest cover and the processes of change represents an integral step, but in many areas of the globe, these processes are still relatively unknown. This study addresses forest cover change in a community in the mountains of western Honduras. Between 1987 and 1996, 9.77 km2 of land was reforested and only 7.48 km2 was deforested, as determined by satellite image analysis. This reforestation is related to the current institutional, biophysical, and socioeconomic contexts. Forests remain primarily on steeper slopes, at higher elevations, and at a distance from settlements and roads. A county ban on logging has allowed regrowth of previously logged areas. Agricultural intensification appears related to abandonment of some marginal lands. Processes of privatization have been occurring; private forests reveal higher reforestation and lower deforestation rates than communal forests. Privatization, however, has favored the wealthy. Thus, the majority has had to depend on shrinking communal forests.

Roads as drivers of change: Trajectories across the Tri-National Frontier in MAP, the Southwestern Amazon

Regional studies of land cover change are often limited by available data and in terms of comparability across regions, by the transferability of methods. This research addresses the role of roads and infrastructure improvements across a tri-national frontier region with similar climatic and biophysical conditions but very different trajectories of forest clearing. The standardization of methodologies and the extensive spatial and temporal framework of the analysis are exciting as they allow us to monitor a dynamic region with global significance as it enters an era of increased road connectivity and massive potential forest loss. Our study region is the “MAP” frontier, which covers Madre de Dios in Peru, Acre in Brazil, and Pando in Bolivia. This tri-national frontier is being integrated into the global economy via the paving of the Inter-Oceanic Highway which links the region to ports in the Atlantic and Pacific, constituting a major infrastructure change within just the last decade. Notably, there are differences in the extent of road paving among the three sides of the tri-national frontier, with paving complete in Acre, underway in Madre de Dios, and incipient in Pando. Through a multi-temporal analysis of land cover in the MAP region from 1986 to 2005, we found that rates of deforestation differ across the MAP frontier, with higher rates in Acre, followed by Madre de Dios and the lowest rates in Pando, although the dominant land cover across the region is still stable forest cover (89% overall). For all dates in the study period, deforestation rates drop with distance from major roads although the distance before this drop off appears to relate to development, with Acre influencing forests up to around 45 km out, Madre de Dios to about 18 km out and less of a discernable effect or distance value in Pando. As development occurs, the converted forest areas saturate close to roads, resulting in increasing rates of deforestation at further distances and patch consolidation of clearings over time. We can use this trend as a basis for future change predictions, with Acre providing a guide to likely future development for Madre de Dios, and in time potentially for Pando. Given the correspondence of road paving to deforestation, our findings imply that as road paving increases connectivity, flows of people and goods will accelerate across this landscape, increasing the likelihood of dramatic future changes on all sides of the tri‑national frontier.

Modeling Spatially and Temporally Complex Land-Cover Change: The Case of Western Honduras*

Abstract This article presents an econometric analysis of land-cover change in western Honduras. Ground-truthed satellite image analysis indicates that between 1987 and 1996 net reforestation occurred in the 1,015-km2 study region. While some reforestation can be attributed to a 1987 ban on logging, the area of reforestation greatly exceeds that of previously clear-cut areas. Further, new area was also deforested between 1987 and 1996. Thus, the observed land-cover changes represent a complex mosaic of changing land-use patterns across time and space. The analysis contributes to the literature on land-cover change modeling in that: (1) it compares two econometric approaches to capture complex and often bidirectional changes in land cover from 1987 to 1996 as a function of agricultural suitability and transportation costs, and (2) it addresses techniques to identify and correct for spatial autocorrelation in a categorical regression framework.

An assessment of Landsat TM band 6 thermal data for analysing land cover in tropical dry forest regions

This research investigates the utility of integrating Landsat band 6 thermal data for land cover classification and, specifically, for the differentiation between successional stages of forest growth. Such successful differentiation has become critical for the assessment of land cover and land use change. The study area is in the state of Yucatan, Mexico, which is a region of predominantly tropical dry forest. Thermal band data measures the emission of energy from the Earths surface and, as this is a function of the surface cover, it can be used as a determinant of land cover type based on the temperatures measured. This research uses a technique of land cover classification utilizing Landsat Thematic Mapper (TM) thermal band data. Land cover classes were found to relate strongly (an eta correlation ratio of 0.804) to band six calculated black body temperatures. Satellite coverages of black body temperatures also provided a unique spatial analysis of the image area using continuous data, not discrete classes. Discriminant analysis revealed that band 6 contains considerable information for the discrimination of land cover classes in the dry tropical forest ecosystem, with a coefficient of 0.354. Band 6 also outperformed many of the individual spectral bands of information, despite their greatly improved (×16) resolution.

Dwindling resources and fragmentation of landscapes around parks: wetlands and forest patches around Kibale National Park, Uganda

Landscapes surrounding parks in most of the developing world, while still containing considerable biodiversity, also have rapidly growing human populations and associated agricultural development. Since the establishment of Kibale National Park first as a Crown Forest Reserve in 1932 and later as a park in 1993 in western Uganda, most access and resource extraction has been prohibited. The park has become nearly a complete island of forested land cover surrounded by intensive small-scale agriculture and some large-scale tea plantations, along with a network of wetland and forest patches. As the population grows outside the park and land becomes more scarce, remaining forests and wetlands are being used more intensively for material resources (e.g., fuelwood, building poles) and converted to other land uses (e.g., pasture, agriculture). This study uses both discrete and continuous data analyses of satellite imagery to examine these diminishing resource bases at the landscape level placing the results within the social context of conservation and parks. Findings reveal that the park boundaries have remained fairly intact whereas, the landscape surrounding the park has become increasingly fragmented. From a landscape perspective, while the park has indeed maintained its forest cover, it has become increasingly islandized with wetland and forest patches in the surrounding landscape becoming smaller in number and size. Those that have survived are now more isolated and even lower productivity than in 1984, which may be a precursor to their eventual loss in this landscape.

Amazon deforestation: Rates and patterns of land cover change and fragmentation in Pando, northern Bolivia, 1986 to 2005:

Much research has focused on deforestation in the Amazon, particularly with proximity to roads and population centers as proximate causes. This research presents the analysis of rates and patterns of land cover change in Pando, northern Bolivia, an area with most of its tropical humid forest still intact. Using a decision tree classifier, five forest/non-forest (FNF) classifications were created for 1986, 1991, 1996, 2000, and 2005 from 40 Landsat images that were preprocessed and mosaicked. FNF trajectory images were created for each date pair to indicate areas of stable forest and non-forest, and areas and rates of de/reforestation. Mean patch size, perimeter-area ratio, fractal dimension, and aggregation index metrics were calculated for the FNF trajectory images based on increasing buffer distances from road and along the main access road. In 2005, forest covered 95% of the area in Pando. Large areas of aggregated deforestation occur nearest the department capital of Cobija, along the border with Brazil, and about 50 km west and east of Cobija along the principal access road. Deforestation becomes patchier with increased distance from the population center and laterally from the road. Multiple non-linear relationships exist between the fragmentation metrics and distance from road. The results have implications for understanding and managing the spatial contiguity of these forests, which provide valuable ecological services as well as the livelihood base for many inhabitants.