Andrew C. Millington

Environmental change in drylands : biogeographical and geomorphological perspectives

Deserts in a warmer world, A. Goudie timescales, environmental change and dryland valley development, D. Nash and D. Thomas mineral magnetic analysis of iron oxides in arid zone soils from the Tunisian Southern Atlas, K. White and J. Walden late Pleistocene and Holocene changes in hillslope sediment supply to alluvial fan systems, A. Harvey and S. Wells natural stabilization mechanisms on Badland slopes, R. Alexander et al responses of rivers and lakes to Holocene environmental change in the Alcaniz Region, M. Macklin et al the palaeolimnological record of environmental change - examples from the arid frontier of Mesoamerica, S. Metcalfe et al lacustrine sedimentation in a high altitude, semi-arid environment, H. Lamb et al abrupt Holocene hydro-climatic events - palaeolimnological evidence from north-west Africa, N. Roberts et al aeolian activity, desertification and the green dam in the Ziban Range, Algeria, J.L. Ballais the ambiguous impact of climate change at a desert fringe, A. Yair the environmental consequences and context of ancient floodwater-farming in the Tripolitanian pre-desert, D. Gilbertson et al evolutionary trends in the wheat group in relation to environment, quaternary climate change and human impacts, M. Blumler post-European changes in creeks of semi-arid rangelands, J. Pickard. (Part contents)

Global land-Cover Change: Recent Progress, Remaining Challenges.

Since time immemorial, humankind has changed landscapes in attempts to improve the amount, quality, and security of natural resources critical to its well being, such as food, freshwater, fiber, and medicinal products. Through the increased use of innovation, human populations have, slowly at first, and at increasingly rapid pace later on, increased its ability to derive resources from the environment, and expand its territory. Several authors have identified three different phases - the control of fire, domestication of biota, and fossil-fuel use - as being pivotal in enabling increased appropriation of natural resources (Goudsblom and De Vries 2004; Turner II and McCandless 2004).

Scale dependence in multitemporal mapping of forest fragmentation in Bolivia: implications for explaining temporal trends in landscape ecology and applications to biodiversity conservation☆

Landsat TM and ETM data were used to create forest/non-forest maps with which spatial patterns of forest fragmentation created by road building, agricultural colonisation and hydrocarbon exploration in Chapare (Bolivia) since the 1980s were analysed. Different spatial patterns of forest fragmentation were identified and analysed using landscape ecology metrics. These patterns are a function of their deforestation histories which, in turn, can be explained by a variety of Bolivian government policies. The relationships between landscape metrics and different simulated spatial resolutions of image data (from 30 to 1100 m) were also examined and most metrics were found to be highly dependent on pixel size. The implications of these findings for biodiversity conservation in humid tropical lowlands are considered.

GIS and remote sensing applications in biogeography and ecology

Co-Editors: Abbreviated Profiles. Acknowledgements: List of Reviewers. 1. Introduction - Thinking Spatially A.C. Millington, et al. 2. A Spectral Unmixing Approach to Leaf Area Index (LAI) Estimation at the Alpine Treeline Ecotone D.G. Brown. 3. The Utilization of Airborne Digital Multispectral Image Dynamics and Kinematic Global Positioning Systems for Assessing and Monitoring Salt Marsh Habitats in Southern California D. Stow, et al. 4. Spatial Variability in Satellite-Derived Seasonal Vegetation Dynamics S.D. Jones, et al. 5. Documenting Land-Cover History of a Humid Tropical Environment in Northeastern Costa Rica Using Time-Series Remotely Sensed Data J.M. Read, et al. 6. Patterns of Change in Land-Use and Land-Cover and Plant Biomass: Separating Intra- and Inter-Annual Signals in Monsoon-Driven Northeast Thailand S.J. Walsh, et al. 7. Barriers and Species Persistence in a Simulated Grassland D.M. Cairns. 8. Feedback and Pattern in Computer Simulations of the Alpine Treeline Ecotone M.F. Bekker, et al. 9. Spatial Pattern and Dynamics of an Annual Woodland Herb L. Bastin, C.D. Thomas. 10. Spatial Analysis of Micro-Environmental Change and Forest Composition in Belize P.A. Furley, et al. 11. The Radiate Capitulum Morph of Senecio Vulgaris L. within Sussex: the Use of GIS in Establishing Origins S. Waite, N. Burnside. 12. A Geographical Information Science (GISci) Approach to Exploring Variation in the Bush Cricket Ephippiger Ephippiger D.M. Kidd, M.G. Ritchie. 13. The GIS Representation of Wildlife Movements: A Framework L. Bian. 14.Stratified Sampling for Field Survey of Environmental Gradients in the Mojave Desert Ecoregion J. Franklin, et al. 15. Development of Vegetation Pattern in Primary Successions on Glacier Forelands in Southern Norway G.A. Grimm. 16. Multi-Scale Analysis of Land-Cover Composition and Landscape Management of Public and Private Lands in Indiana T.P. Evans, et al. 17. Shifting Cultivation Without Deforestation: A Case Study in the Mountains of Northwestern Vietnam J. Fox, et al. 18. Linking Biogeography and Environmental Management in the Wetland Landscape of Coastal North Carolina, The difference between nationwide and individual wetland permits N.M. Kelly. Index.

Constraining the timing of alluvial fan response to late quaternary climatic changes, southern Tunisia

The evolution of the Oued es Seffaia alluvial fan during the last 50,000 years is analyzed in the light of chronometric data derived from AMS radiocarbon and optical dating techniques. These ages have enabled the temporal constraint of the distalward progression of the intersection point (the upper limit of the locus of deposition) which has resulted in the telescopic segmentation of the fan. Comparison of these data with the Late Quaternary climatic history of the Maghreb highlights several problems of interpretation; due both to our limited knowledge of regional palaeoclimates and of the response of dryland fluvial systems to climate changes. However, our data provide some evidence to suggest that fan incision and formation of telescopic segments occurs in response to changes from arid to less arid conditions, supporting the conclusions of some of the work from other areas.

Coca and Colonists: Quantifying and Explaining Forest Clearance under Coca and Anti-Narcotics Policy Regimes

The impacts of coca cultivation and coca eradication on rates of humid tropical forest clearance were examined in the agricultural colonization zone of Chapare, Bolivia. Using satellite image- derived land-use maps, interviews with farmers, and analyses of economic data and policy documents, forest clearance rates were analyzed in three contrasting communities from 1963 to 2003. Deforestation rates were very low from the late 1970s to the early 1990s when coca cultivation was widespread and anti- coca policies were weakly enforced. Before and after this period, deforestation rates were significantly higher. This study provides the first detailed quantitative analysis of deforestation rates under different policy regimes in a coca source region. It provides weak support for the argument that labor constraints lead to a reduction in forest clearance rates during periods of coca cultivation advanced by Kaimowitz (1997); but stronger support for Henkels (1995) hypothesis that farmers would clear large areas of forest after abandoning coca to maintain household incomes. However, economic arguments based on household data alone are inadequate in explaining forest clearance in this region, and a political ecological approach that analyses economic drivers in a policy framework provides better explains deforestation dynamics.

Spatial and temporal scale issues in determining biomass burning regimes in Bolivia and Peru

ATSR‐2 active fire data from 1996 to 2000, TRMM VIRS fire counts from 1998 to 2000 and burn scars derived from SPOT VEGETATION (the Global Burnt Area 2000 product) were mapped for Peru and Bolivia to analyse the spatial distribution of burning and its intra‐ and inter‐annual variability. The fire season in the region mainly occurs between May and October; though some variation was found between the six broad habitat types analysed: desert, grassland, savanna, dry forest, moist forest and yungas (the forested valleys on the eastern slope of the Andes). Increased levels of burning were generally recorded in ATSR‐2 and TRMM VIRS fire data in response to the 1997/1998 El Niño, but in some areas the El Niño effect was masked by the more marked influences of socio‐economic change on land use and land cover. There were differences between the three global datasets: ATSR‐2 under‐recorded fires in ecosystems with low net primary productivities. This was because fires are set during the day in this region and, when fuel loads are low, burn out before the ATSR‐2 overpass in the region which is between 02.45 h and 03.30 h. TRMM VIRS was able to detect these fires because its overpasses cover the entire diurnal range on a monthly basis. The GBA2000 product has significant errors of commission (particularly areas of shadow in the well‐dissected eastern Andes) and omission (in the agricultural zone around Santa Cruz, Bolivia and in north‐west Peru). Particular attention was paid to biomass burning in high‐altitude grasslands, where fire is an important pastoral management technique. Fires and burn scars from Landsat Thematic Mapper (TM) and Enhanced Thematic Mapper (ETM) data for a range of years between 1987 and 2000 were mapped for areas around Parque Nacional Río Abiseo (Peru) and Parque Nacional Carrasco (Bolivia). Burn scars mapped in the grasslands of these two areas indicate far more burning had taken place than either the fires or the burn scars derived from global datasets. Mean scar sizes are smaller and have a smaller range in size between years the in the study area in Peru (6.6–7.1 ha) than Bolivia (16.9–162.5 ha). Trends in biomass burning in the two highland areas can be explained in terms of the changing socio‐economic environments and impacts of conservation. The mismatch between the spatial scale of biomass burning in the high‐altitude grasslands and the sensors used to derive global fire products means that an entire component of the fire regime in the region studied is omitted, despite its importance in the farming systems on the Andes.

Population dynamics, socioeconomic change and land colonization in northern Jordan, with special reference to the Badia Research and Development Project area

Abstract The paper reports on preliminary observations from northern Jordan aimed at testing the view that people migrate from areas of relatively high potential for cultivation to the marginal semi-arid/arid frontier because of social differentiation, political factors or environmental constraints. Cultivated areas have been mapped from multi-date remotely sensed imagery, a typology of fields in the area has been constructed, and their dynamics between 1972 and 1992 analysed. In addition, semi-structured interviews with farmers attempted to understand the reasoning behind village growth, changing farming systems and cultivation practices. The findings are discussed in the context of the areas demography and national and regional shifts in economic policy.

Modelling catchment-scale nutrient transport to watercourses in the U.K.

Water resource managers require catchment-scale nutrient transport models to help in the investigation and control of diffuse pollution. Many different models exist for water and pollutant movement, causing problems of selection because each model has often been constructed for specific purposes, and the choice of an appropriate one is difficult: wrongly applied models can lead to unreliable results and misleading information. The selection of a model for estimating phosphorus loss from a lowland English catchment is described. 14 models, whose underlying principles had been published, were evaluated. ‘SWAT’ was found to be the most suitable. It has several favourable qualities, but also several shortfalls which may impair its predictive ability. Their identification enables the model code to be re-written. Reliability estimation is needed to ensure that the ranges of model prediction are known.

Unravelling the patterns of alluvial fan development using mineral magnetic analysis: examples from the Sparta Basin, Lakonia, southern Greece

Mineral magnetic analysis of B-horizons of soils developing upon the surfaces of alluvial fans was undertaken in order to: (i) differentiate and rank discrete fan surfaces by order of formation; (ii) establish whether fan surfaces formed simultaneously in adjacent fan systems; and (iii) deduce probable patterns of fan development. The results of the analysis indicate that the greatest concentration of ferrimagnetic and anti-ferromagnetic minerals occurs within soils which have developed upon the proximal fan surfaces with a progressive reduction in magnetic minerals in soils associated with medial and distal surfaces. The build-up of magnetic minerals in the proximal fan soils suggests that these surfaces formed first followed by the medial and distal surfaces. With the exception of the Kalivia Sokas fan, the majority of depositional events responsible for fan surface formation occurred simultaneously, suggesting that adjacent fan systems share broadly similar depositional histories. Although the precise timing of depositional events is uncertain, it is probable that by the end of the late Pleistocene, small, largely undissected fans comprising two to three surfaces had formed. At the start of the Holocene, fan systems experienced significant fanhead incision. A net distal extension of the fan trench coupled with a progressive basinward shift of the locus of deposition during the middle and late Holocene resulted in formation of medial and distal fan surfaces. Changes in climate are deemed to be the major control of fanhead incision, fan trenching and fan surface formation. However, the likely effects of long-term tectonic activity and approximately five thousand years of human occupation upon fan development in the Sparta Basin remain unclear. Copyright