**1. Introductory remarks**

Tropical mountain environments can be approached in a three-dimensional perspective taking into consideration the horizontal or lateral as well as the vertical dimensions of geographical space: Zimmerer [2] speaks of "vertical environments". In the case of the tropical Andes, the configuration of the natural environments and of the human landscape is further differentiated by the extent of the Cordilleras on both sides of the Equator from the Caribbean coast (about 11°N) to the tropic of Capricorn (about 23.4°S). Facing the Pacific Ocean with its different ocean currents on its western side and the vast interior, lowland areas of the Orinoco, Rio Negro

and Amazon watersheds to the east furthermore result in a marked landscape contrast as one crosses the mountain ranges and highland basins from west to east.

As early as 1807, von Humboldt and Bonpland described the vertical arrangement of ecological zones in their famous illustration of climate and vegetation of the Chimborazo in Ecuador [3]. Troll [4, 5] and Lauer [6–8] described and compared the altitudinal zonation of climatic factors and vegetation in tropical mountains in general and also specifically in the Andes. They distinguished the principal zones of the *tierra caliente*, the *tierra templada*, the *tierra helada* and the *tierra nival* or *nevada* from the base to the top of high tropical Andean mountains. They further differentiated between the humid, semi-humid, semiarid and arid Andes and illustrated these zones by their famous three-dimensional altitudinal and latitudinal models. They also showed that the climatic characteristics of the tropical Andes have a major impact on land use, settlements and agricultural activities. Of great significance are in particular critical temperature thresholds, e.g. for the growth of specific tropical cultigens and of the occurrence of frost. In terms of humidity levels, the humid and semi-humid Andes are characterized by between 12 and 7 humid months (precipitation higher than potential evaporation), the arid and semiarid Andes by 6 to 12 arid months (evaporation higher than precipitation). In a generalized model, the author attempted to portray the altitudinal zonation of ecology, agricultural land use, settlements, and health risks for the humid and the semiarid and arid Andes (**Figure 1**).

A pioneering contribution to the concept of altitudinal ecological and human zonation was made by Murra [9, 10]. He states that life of the rural Andean world was shaped by the "verticality" of ecological conditions and that families, villages and ethnic communities have traditionally attempted to control as many micro-ecological zones as possible (*Control Vertical* or *Mitimagkuna*), the so-called *archipiélagos verticales*. Drawing on Murra's work and based on his own research, Brush [11–13] distinguished three major types of control and integration of Andean ecological zones and resource areas. The "compact type" is one in which different ecological zones occur in close proximity to each other and are easily accessible to the community. In the case of the "archipelago type", the ecological zones used by a group of peasants are more distant from each other and are often separated by unused areas, thus requiring more extended travel times. This may require the establishment of a series of permanent or semipermanent "colonies", away from the home community, in these different ecological zones, as well as a system of exchanges between the home community and the colonies based on reciprocity and redistribution. In the "extended type", each peasant group exploits a single or a few ecological zones, often specializing in certain products, and exchanges goods with other groups living and exploiting other ecozones ([11]: 292-295). In a summarizing overview, Forman [14] has discussed the "verticality concept" with its implications and applications for the Andes. She comes to the conclusion that the verticality models still provide useful guidelines for rural development in the Andes.

In a rather provocative paper, Allan [15] had rejected the "environmental determinism" of traditional altitudinal zonation models, arguing that they are "no longer suitable for characterizing mountain ecosystems now that human activity is directed to new motorized transportation networks linked to a wider political economy and no longer dependent on altitude" ([15]: Abstract, 185). Instead, he proposed an "accessibility model" of land use in a hypothetical mountain landscape. While mountain geographers would agree that a simplistic and unrestricted environmental determinism has to be rejected, many of them (among them [16]: 197-198), based on their empirical findings, have taken the position that mountain people for a long time have adapted to the geofactors of altitude, relief, distance, climate, vegetation, soil and hazard exposure, while recognizing that new developments, among

**167**

**Figure 1.**

*Horizontal and Vertical Archipelagoes of Agriculture and Rural Development in the Andean…*

them accessibility, transportation and intensified lowland-highland interactions, have influenced and modified human activities in mountains. In his rural research in Ecuador, Peru and Bolivia, the author [17–20] identified a vast array of factors

• Altitude and relief configuration, erosion and sedimentation.

*Altitudinal zonation of ecology and agricultural land use in the tropical Andes (Stadel 1989).*

• Distance, proximity or remoteness to service centres and core areas.

influencing agricultural activities and rural land use:

• Climate, vegetation and soils.

• Natural hazards.

*DOI: http://dx.doi.org/10.5772/intechopen.86841*

*Horizontal and Vertical Archipelagoes of Agriculture and Rural Development in the Andean… DOI: http://dx.doi.org/10.5772/intechopen.86841*

#### **Figure 1.**

*Sustainability Assessment at the 21st Century*

semiarid and arid Andes (**Figure 1**).

and Amazon watersheds to the east furthermore result in a marked landscape contrast as one crosses the mountain ranges and highland basins from west to east. As early as 1807, von Humboldt and Bonpland described the vertical arrangement of ecological zones in their famous illustration of climate and vegetation of the Chimborazo in Ecuador [3]. Troll [4, 5] and Lauer [6–8] described and compared the altitudinal zonation of climatic factors and vegetation in tropical mountains in general and also specifically in the Andes. They distinguished the principal zones of the *tierra caliente*, the *tierra templada*, the *tierra helada* and the *tierra nival* or *nevada* from the base to the top of high tropical Andean mountains. They further differentiated between the humid, semi-humid, semiarid and arid Andes and illustrated these zones by their famous three-dimensional altitudinal and latitudinal models. They also showed that the climatic characteristics of the tropical Andes have a major impact on land use, settlements and agricultural activities. Of great significance are in particular critical temperature thresholds, e.g. for the growth of specific tropical cultigens and of the occurrence of frost. In terms of humidity levels, the humid and semi-humid Andes are characterized by between 12 and 7 humid months (precipitation higher than potential evaporation), the arid and semiarid Andes by 6 to 12 arid months (evaporation higher than precipitation). In a generalized model, the author attempted to portray the altitudinal zonation of ecology, agricultural land use, settlements, and health risks for the humid and the

A pioneering contribution to the concept of altitudinal ecological and human zonation was made by Murra [9, 10]. He states that life of the rural Andean world was shaped by the "verticality" of ecological conditions and that families, villages and ethnic communities have traditionally attempted to control as many micro-ecological zones as possible (*Control Vertical* or *Mitimagkuna*), the so-called *archipiélagos verticales*. Drawing on Murra's work and based on his own research, Brush [11–13] distinguished three major types of control and integration of Andean ecological zones and resource areas. The "compact type" is one in which different ecological zones occur in close proximity to each other and are easily accessible to the community. In the case of the "archipelago type", the ecological zones used by a group of peasants are more distant from each other and are often separated by unused areas, thus requiring more extended travel times. This may require the establishment of a series of permanent or semipermanent "colonies", away from the home community, in these different ecological zones, as well as a system of exchanges between the home community and the colonies based on reciprocity and redistribution. In the "extended type", each peasant group exploits a single or a few ecological zones, often specializing in certain products, and exchanges goods with other groups living and exploiting other ecozones ([11]: 292-295). In a summarizing overview, Forman [14] has discussed the "verticality concept" with its implications and applications for the Andes. She comes to the conclusion that the verticality models still provide useful guidelines for rural development in the Andes.

In a rather provocative paper, Allan [15] had rejected the "environmental determinism" of traditional altitudinal zonation models, arguing that they are "no longer suitable for characterizing mountain ecosystems now that human activity is directed to new motorized transportation networks linked to a wider political economy and no longer dependent on altitude" ([15]: Abstract, 185). Instead, he proposed an "accessibility model" of land use in a hypothetical mountain landscape. While mountain geographers would agree that a simplistic and unrestricted environmental determinism has to be rejected, many of them (among them [16]: 197-198), based on their empirical findings, have taken the position that mountain people for a long time have adapted to the geofactors of altitude, relief, distance, climate, vegetation, soil and hazard exposure, while recognizing that new developments, among

**166**

*Altitudinal zonation of ecology and agricultural land use in the tropical Andes (Stadel 1989).*

them accessibility, transportation and intensified lowland-highland interactions, have influenced and modified human activities in mountains. In his rural research in Ecuador, Peru and Bolivia, the author [17–20] identified a vast array of factors influencing agricultural activities and rural land use:

