The Sierra Nevada de Santa Marta (SNSM) is the northern geological outlier of the Andean Mountain Chain and one of the most complex ecosystems in the world. It is a massive mountain of pyramidal shape facing the tropical Caribbean Sea. Reaching 5,775 masl, it is the highest mountain in the world so close to an ocean—only 48 km from the modern shoreline. It is Colombia’s highest mountain with permanent glaciers. And due to its isolation from other highlands, and its great vertical climatic variability, it is characterized by extreme biological endemism. Consequently, it has attracted scientific studies since
Figure 22.5. Map of the agricultural ridge fields (green) and platforms (red) in the middle Cano Rabon. Area shown is 49.45 m2. (After Plazas et al. 1993:49)
The nineteenth century (Reclus 1881; Simons 1879, 1881; Allen 1900; Todd and Carriker 1922; van der Hammen and Ruiz 1984; Strewe and Navarro 2004; Hooghiemstra and van der Hammen 2004).
The SNSM is striking not only for its ecosystems diversity, that ranges from tropical bays to frigid glaciers, but also for the vertical stacking of its systems, and their decreasing horizontal variation with altitude, as in other parts of the Andes. The general explanation is that the horizontal and vertical ecological variation is a consequence of climatic factors such as patterns of wind and marine currents that affect the mountain differently. For example, the region of the lower Gaira River drainage is affected by fohn-type winds that dry the area between the mountains and the sea (western side of the SNSM) (Figure 22.6). In contrast, the Tairona Park region is affected by winds that run from the sea to the mountain (Herrman 1984) or in the case of the upper Buritaca, by mountain valley winds. This wind variation affects the precipitation and consequently, the vegetation. Precipitation throughout the SNSM varies greatly as well, with altitude and wind patterns. In regard to vegetation zones, for example, the region of Gaira is
Figure 22.6. General view of lower Gaira floodplain. The hills have xerophitic vegetation. (Augusto Gyuela-Caycedo)
Mainly tropical thorn woodland or semi - deciduous lowland forest (Cleef et al. 1984). Tairona Park vegetation changes gradually from west to the east, at the same altitude (0-500 masl), from tropical thorn woodland, to very dry tropical forest, to equatorial rainforest. In contrast, the upper Buritaca has an Andean rainforest known as upper montane rain forest (Cleef and Rangel 1984).
Topographic variation can be illustrated by considering slope within the regions under archaeological analysis. For example, Gaira is characterized by landscape inclination below 20%, but with the surrounding hills between 20 to 40%. In contrast, small floodplains and the end of the bays surrounded by hills with slopes between 60 to 80% characterize the Tairona Park. The upper Buritaca is located in a landscape where most of the terrain is between 60% to more than 80% of slope (Bartels 1984). Furthermore, the Gaira region is located on the littoral in an area of deep open bays with sandy and muddy floors, which are seasonally affected by the Magdalena River sediments. Tairona Park is characterized by several harbors with coral and rock floors that are affected by deep currents abundant in phytoplankton, that makes it one of the richest fishing areas of northern Colombia (Hernandez 1986).
Great ecological variation, however, is typical of the Andes generally, where unique combinations of temperature, precipitation, wind patterns, and landscape morphology create unique niches of alpha and beta diversity. Significantly, in the SNSM, our understanding of the distribution of rainforest and pre-Hispanic human communities is still problematic. The only rainforest that currently exists is restricted to the northwest corner of this pyramidal mountain, in valleys like the upper Guachaca, Buritaca, and Don Diego rivers (Figures 22.7, 22.8), the same area with the only pre-Hispanic urban settlements, with high residential density. These settlements consist of hundreds of terraces at intersections in a network of stone-paved roads (Oyuela-Caycedo 1990; Herrera 2000). In contrast, the northeast, south and most of the west side of the SNSM lacks gallery forest, as well as archaeological settlements comparable to those in the northwest (Figures 22.9, 22.10). The
Figure 22.7. General view of the tropical cloud forest of the upper Buritaca Valley. The main platform of the archaeological site of Ciudad Perdida is located at the center. (Augusto Oyuela-Caycedo)
Figure 22.8. General view of the ridge where Ciudad Perdida is located under the canopy; the central opening is the main terrace of Ciudad Perdida. (Augusto Oyuela-Caycedo)
Figure 22.9. The upper Palomino river valley from the archaeological site of Nebini (Jaguar Creek). Deforestation is the result of human action since prehispanic times up to the present by the Kogi Indians. (Augusto Oyuela-Caycedo)
Figure 22.10. Archaeological terrace at Nebini, close to 1,400 masl. Note projected slabs at the edge of the terrace and menhir beside human scale. (Augusto Oyuela-Caycedo)
Northeast and east of the SNSM is where indigenous populations such as the Kogi and Ijka live today (Oyuela-Caycedo 1991, 1998; Reichel-Dolmatoff 1950,1951a, b). The south and west were colonized for agricultural and cattle production from the seventeenth century on, and in the eighteenth century, a small population of English were granted rights to settle by the Spanish crown (Barros Blanco 1996).
The question is how can we explain the persistence of rainforest in an area where previous human occupation was so dense in such a delicate environment of steep slopes and rapid erosion? Most of the archaeological evidence of the hundreds of archaeological settlements of the Tairona culture are found in this northwest part of the SNSM. The rest of the SNSM is devastated (Cavelier et al. 1998), reduced to small fragmented patches of rainforest where no evidence of complex archaeological occupation exists, but where indigenous populations live, up to the present.
I believe that the prehistory and ecology of the SNSM rainforest can be understood from an historical ecology approach (see Chapters 11 and 12 in this volume for a discussion of this concept). The reduction of the rainforest to fragmented ridges in the indigenous territories can also be understood with a historical ecological study of its past.
World History
