This doctoral thesis addresses one of the fundamental issues and problems of many tropical mountain regions: high-altitude ecological changes and environmental degradation under the impact of expansion and intensification of agricultural activities. In the equatorial Andes of Ecuador, the ecologically sensitive herbaceous belt of the páramos, traditionally used for extensive pastoral activities and some field cultivation of tuber culti-gens and hardy grains, has become an “active altitudinal pioneer front” (p 11).

The intensification of agricultural land use and the expansion of the agricultural and settlement frontier zone have often been attributed to rural population growth and land shortages. María Fernanda López Sandoval's research in 3 selected páramo regions of Northern Ecuador suggests, however, that the altitudinal frontier is not expanding in all parts of the Sierra, and that the reasons for expanding or stagnating agricultural and settlement pioneer zones are complex. The author identifies the following major factors for the altitudinal expansion of the frontiers: 1) the participation of the labor force in rural non-farm activities or as wage labor in agrarian enterprises; 2) the availability of cultivable land on former haciendas; 3) an expansion of the farm area for the production of cash crops; and 4) the establishment of a dwelling and/or an agricultural parcel to ascertain the membership of an “ethnic community” (p 143).

Whereas previous research on páramo environments has focused primarily on ecology and on human-induced ecological effects on these high-altitude tropical grasslands, López Sandoval's research provides new insights into these fragile environments through its focus on cultural and socioeconomic aspects and their impact on the páramo. The thesis is organized in 8 major chapters. An introductory chapter states the principal research and investigation targets, and introduces the northern Ecuadorian Sierra as the regional framework of the study. It also establishes the research methods and discusses basic concepts relating to the research theme. Making reference to an ample pool of scientific literature, Chapter 2 aims at providing a “state-of-the-knowledge” of the South American páramo, with particular attention given to the altitudinal arrangements of ecological and agropastoral zones. In Chapter 3, the 3 páramo research regions of El Angel, Cangahua, and West Saquisilí are introduced. Furthermore, the 2 principal field research methods are presented: 1) analysis of air photographs and remote sensing data to assess land cover and land use changes for a 3-phase period from 1956/65 to 1993; and 2) extensive fieldwork, with data collected from numerous farmer interviews and participatory field observation of farming systems.

The following major chapters examine in detail the different types of “drivers of frontier expansion” at both regional and local levels. At the regional level, the agrarian legislation and land tenure system, as well as the ensuing demographic development, are explored in a historical perspective. Among the “socioeconomic drivers” at the local level, demographic aspects, land property, and farming systems are discussed. Here, the author proposes a 4-part typology of farming systems based on the relative emphasis of the agricultural operation on livestock and field cultivation, and of the type of cultivation practiced in the agricultural frontier zone. An additional shorter chapter addresses the spatial dimension of the agricultural and settlement frontier zone of the páramo. With the aid of a detailed data analysis, the 3 páramo study regions are compared and contrasted in their land cover and land use changes over a 30-year period. This analysis reveals that each region has different geographical and socioeconomic frameworks and driving forces, and exhibits different forms of agricultural frontiers: stagnating, contracted and expansive. The final chapters are devoted to an interpretation of the major results, particularly those relating to the land cover / land use changes, and to a general discussion of the research and general conclusions.

The thesis is complemented by 4 annexes and a glossary that includes a definition of key terms, as well as an English, German, and Spanish glossary of basic concepts. Unfortunately, the latter contains incorrect or inaccurate translations of terms into German, as well as an unacceptable number of printing or spelling mistakes. The study also includes 13 tables and the impressive number of 36 figures. The 14 multicolor supplements are of particular value: one map shows vegetation types of the Ecuadorian Sierra above 3000 m, others illustrate the development of the agricultural frontier in the 3 study areas. A model depicting the different rotation and cultivation cycles of agricultural plots in the páramo belt is particularly interesting. The international list of references includes 347 titles up to the publication year of 2003, featuring titles in Spanish, English, German, and French. While this is undoubtedly a laudable effort, the bibliography is not fully satisfactory, mainly because of a very inadequate listing (only 2 titles!) of the impressive páramo literature in French, noticeable omissions of relevant contributions in the other languages, an incomplete list of websites, and reoccurring spelling mistakes.

Overall, this is a high-quality and innovative thesis. It is based on extensive field research on selected páramo regions and testifies to the author's commitment to, and enthusiasm for, these high-altitude environments and their rural livelihoods. In spite of some shortcomings and deficiencies, the book merits wide international dissemination and recognition, as it makes a significant new contribution to the understanding of the complex ecological and socioeconomic linkages of the páramos of the Northern Andes over 3 decades.