Editorial: Physical geography beyond the 20th century

In his book “The Nature of Physical Geography”, published in 1985, Ken Gregory wrote in the preface: “Physical geography is now poised for great development in view of the focus of recent works and research and the advent of new technology including the microcomputer, electronic instrumentation and enhanced remote sensing” (Gregory, 1985). Indeed, during the last twenty years we saw a growing number of books and articles in which physical geographers direct their attention definitively to new..

Geoarchaeological observations on the Roman town of Ammaia

This article presents, for the first time, multidisciplinary geoarchaeological work by a joint Belgo-Italian team from the universities of Ghent and Cassino in and around the Roman urban site of Ammaia in the northern Alentejo region of Portugal. This project is a geoarchaeological case study to investigate the conditioning effects of landscape and landscape evolution on a Roman urban site (and vice versa) in the Iberian peninsula. The site and landscape presentation is followed by a brief discussion of the aims and approaches of the chosen geoarchaeological strategy. With this study we approach the cultural landscape around Ammaia by means of techniques which combine methods both of the geosciences and of archaeological survey. The specific problems of assessing and reconstructing a Roman landscape, much altered by physical movements of the soil and by a two-millennia long period of human interference, will therefore be tackled in a multidisciplinary way. This means first of all making use of all relevant cartographic material, available aerial photographs and relevant satellite images. All important pre-existing archaeological information is inventoried and mapped and new fieldwork organised. This fieldwork, combining traditional archaeological survey techniques and geomorphologic observations, is being used to build a database of landscape features and sites with archaeological relevance for the period concerned. As many field data and cartographic elements as possible are being assembled in a Geographic Information System, specifically developed for this project. This GIS has already enhanced much new cartographic material of crucial importance in reconstructing the landmarks of the site and territory of Ammaia in the first centuries of our era and has helped to evaluate and interpret the evolution of the landscape shortly before, during, and since Roman times. A large part of this contribution is dedicated to reporting on some major observations and results obtained during three field campaigns, in the summers of 2001, 2002 and 2004. These results relate primarily to three fields of archaeological concern with specific relevance to the landscape background: the tracing of the circuit wall of the Roman city, the intra-urban cartography and the supply of water to the urban area during Roman imperial times. The authors believe these investigations to be examples of good practice in the field of geoarchaeology of the classical Mediterranean landscape

Participatory approach for integrated basin planning with focus on disaster risk reduction : the case of the Limpopo river

This paper defends the idea that a participatory approach is a suitable method for basin planning integrating both water and land aspects. Assertions made are based on scientific literature review and corroborated by field experience and research carried out in the Limpopo River basin, a transboundary river located in southern Africa which is affected by periodical floods. The paper explains how a basin strategic plan can be drafted and disaster risk reduction strategies derived by combining different types of activities using a bottom-up approach, despite an institutional context which operates through traditional top-down mechanisms. In particular, the "Living with Floods" experience in the lower Limpopo River, in Mozambique, is described as a concrete example of a disaster adaptation measure resulting from a participatory planning exercise. In conclusion, the adopted method and obtained results are discussed and recommendations are formulated for potential replication in similar contexts of the developing world

Editorial: Physical geography beyond the 20th century

In his book “The Nature of Physical Geography”, published in 1985, Ken Gregory wrote in the preface: “Physical geography is now poised for great development in view of the focus of recent works and research and the advent of new technology including the microcomputer, electronic instrumentation and enhanced remote sensing” (Gregory, 1985). Indeed, during the last twenty years we saw a growing number of books and articles in which physical geographers direct their attention definitively to new..

Flood analysis of the Limpopo River basin through past evolution reconstruction and a geomorphological approach

This research reconstructs the past evolution of the Limpopo River, a transboundary system located in southeastern Africa, and describes its geomorphological settings through a literature review and field work activities, with the aim of analysing flood hazard in the basin. Major changes have occurred since the late Jurassic-early Cretaceous period due to successive tectonic events. The paper demonstrates that the apparently abandoned drainage conformation of the palaeo-Limpopo in the upper and middle stretches of the river today constitutes preferential flood-prone areas in the case of major rainfall events. An important palaeo-delta is identified in the lower Limpopo, which imposes a particular drainage pattern onto the floodplain in Mozambique and influences the flood dynamics at present. The adopted method is helpful in determining flood hazard in a data-scarce area showing complex fluvial dynamics, and allows for the identification of unsuitable locations for human settlements

A century of tree line changes in sub-Arctic Sweden shows local and regional variability and only a minor influence of 20th century climate warming

Aim Models project that climate warming will cause the tree line to move to higher elevations in alpine areas and more northerly latitudes in Arctic environments. We aimed to document changes or stability of the tree line in a sub-Arctic model area at different temporal and spatial scales, and particularly to clarify the ambiguity that currently exists about tree line dynamics and their causes. Location The study was conducted in the Tornetrask area in northern Sweden where climate warmed by 2.5 degrees C between 1913 and 2006. Mountain birch (Betula pubescens ssp. czerepanovii) sets the alpine tree line. Methods We used repeat photography, dendrochronological analysis, field observations along elevational transects and historical documents to study tree line dynamics. Results Since 1912, only four out of eight tree line sites had advanced: on average the tree line had shifted 24 m upslope (+0.2 m year-1 assuming linear shifts). Maximum tree line advance was +145 m (+1.5 m year-1 in elevation and +2.7 m year-1 in actual distance), whereas maximum retreat was 120 m downslope. Counter-intuitively, tree line advance was most pronounced during the cooler late 1960s and 1970s. Tree establishment and tree line advance were significantly correlated with periods of low reindeer (Rangifer tarandus) population numbers. A decreased anthropozoogenic impact since the early 20th century was found to be the main factor shaping the current tree line ecotone and its dynamics. In addition, episodic disturbances by moth outbreaks and geomorphological processes resulted in descent and long-term stability of the tree line position, respectively. Main conclusions In contrast to what is generally stated in the literature, this study shows that in a period of climate warming, disturbance may not only determine when tree line advance will occur but if tree line advance will occur at all. In the case of non-climatic climax tree lines, such as those in our study area, both climate-driven model projections of future tree line positions and the use of the tree line position for bioclimatic monitoring should be used with caution