Environmental and Socio-Economic Changes in the Rural Andes: Human Resilience and Adaptation Strategies - Impact of Global Changes on Mountains: Responses and Adaptation - page 420

offer a remarkable range of agricultural potential. This is complemented by a
multitude of topographic, hydrographic and climatic niches. The landscape
is further overlaid by a cultural mosaic and by the recent impact of political
ecology parameters. These agricultural 'archipelagos' and 'overlapping
patchworks' (Zimmerer 1999) of human utilization also represent fragile and
potentially vulnerable regions exposed to environmental risks and to socio-
economic or political threats. The external natural and human stimulators or
stressors affecting the environment and people are complemented by new
challenges and changes within the rural societies. Thus, farming and human
settlement in the Andes have millennia tradition of an 'open' rural system,
constantly adapting to an array of changing environmental, political,
cultural, social and economic conditions (Stadel 2003b, Stadel 2008).
Environmental Changes
As is the case in many other high mountains, the Andes are susceptible to
widespread and frequently occurring natural risks and hazards. This has
resulted, in specifi c geographic and temporal contexts, to conditions of
vulnerability and criticality for rural communities, at times even to social
and economic disasters. Particularly harmful have been the suddenly
occurring earthquakes and volcanic eruptions which often set in motion
other geomorphic processes. A notable example of such events in recent
times has been the earthquake in the Santa Valley of Peru in 1970 which
broke off a large part of the rock and glacier summit face of the Huascarán
and buried the settlement of Yungay causing the sudden death of some
20,000 people. Since that time, the old townsite of Yungay was not rebuilt,
with new Yungay being founded nearby, but in a presumably safer
location. In the Cordillera Blanca, glacier ice, rock and debris material have
sometimes also fallen into high mountain lakes, generating huge spillovers
and fl ashfl oods further below. Another devastating disaster example was
the 1985 eruption of the Nevado del Ruiz in Colombia which triggered a
massive lahar in the Langunilla Valley at its base and devastated the town
of Armero which was never rebuilt but left as a memorial site.
Extraordinary weather and climate events are also deeply affecting the
life of Andean people and entailing major changes in Andean environments
and societies. Whereas sudden weather events tend to have rather short-
term impacts in the form of excessive rains and fl ooding, droughts, frost,
snowfall or hail, periodic weather changes generated by anomalies of the
currents of the Pacifi c Ocean, called El Niño- and La Niña- events, generally
have vaster and longer-lasting repercussions. The abnormally warm
El Niño generates excessive rains in the Pacifi c coastal plains of Ecuador and
Peru and the adjacent western Cordillera, while the Altiplano -region of Peru
and Bolivia experience, under these conditions, a defi cit of precipitation.