Transcript No Slide Title

Challenges of Data Integration in the Study of a Complex System:
A Case Study of Lake Atitlán in Guatemala
Edwin J. Castellanosa, Maricruz de Mejíaa,b, Beatriz Lópezb, Nancy Girón,a and Willy Knedela
a
b
Universidad del Valle de Guatemala
Medical Entomology Research and Training Unit/Guatemala-CDC
ABSTRACT
SITE DESCRIPTION
The watershed of Lake Atitlán in the Highlands of Guatemala is presented as an
example of the high level of complexity found in a system that involves natural, social, and
economic forces interacting in a small but extremely diverse geographical area. This poster
describes our efforts to use a multidisciplinary approach to study the two main forces of
natural and social change in the area: coffee production and tourism; as well as to
understand how these interact with a highly intertwined system of institutions.
We used Landsat TM images to study the large changes in land use brought about by
the increase in coffee production in the last decades. This crop has meant mixed blessings in
terms of vegetation cover for the area. Our analysis shows that coffee has been the single
most important cause of forest cover loss in the area: 14% of the land was changed from
forest to coffee between 1986 and 1996. On the other hand, for the same period, shaded
coffee plantations substituted 6,000 ha. of corn fields, replacing an annual crop of little
ecological value with an agroforestry system that provides habitat for wildlife and better soil
conservation, among other environmental benefits.
Tourism has been another important force of change in the area. Due to its natural
beauty and rich cultural heritage, the Atitlán area has developed in the last decades as the
third most important tourist destination in the country. The number of hotels, resorts, and
chalets around the lake has increased by a factor of five in the last forty years. Again, the
boom in this industry has been a mixed blessing for the locals: indigenous groups who have
lived there for hundreds of years, and who are now struggling to adapt to living with outsiders
from other parts of the country as well as from other parts of the world.
These natural and social changes are occurring with the backdrop of an increasingly
complex system of institutions interacting in the area. We have identified seven governmental
institutions having jurisdiction in the region and various national and international nongovernmental organizations working mainly with the indigenous groups who, themselves,
zealously keep their own system of institutions. In spite of the large number of institutions
present, little is achieved in terms of planning and managing the region in a sustainable way
and the degradation of the environmental conditions is now evident in both the land and in
the water.
We have recently started an effort to link an additional set of data to this analysis
integrating land use, social elements, and institutional aspects. We are examining the use of
biophysical parameters of lake water quality: nutrient levels, presence of fecal bacteria,
pesticide residue levels, and the like, as integrative indicators of changes in the different
factors that affect the resources and the people in the watershed. The simultaneous analysis
of sets of data from various scientific disciplines is a challenging task for the scientific team,
but can provide the decision-makers with an invaluable tool.
92°
90°
89°
 The lake has no surface outlets; underground fissures and
seep holes allow water to filter to two rivers draining to the
Pacific.
 Lake sides are steep, due to its geological origins. The
lake lies in a heavy seismic zone.
Town of Sololá
Town of San Lucas
How can we use physical and chemical water quality parameters as
integrative indicators of the effects of human-induced changes on
the resources of a lake watershed?
METHODS
Landsat TM images from 1986 and 1996 were used to
examine patterns of land use and land-cover change for the
region.
18°
Belize
17°
ex
ic
o
17°
Caribbean
Sea
Guatemala
16°
16°
15°
15°
Honduras
14°
14°
El Salvador
Pacific Ocean
92°
91°
90°
89°
88°
 The region is considered one of the poorest in the country
with high rates of illiteracy and public health problems.
GENERAL RESEARCH QUESTION
Pumping water to
analyze for Giardia
88°
 Hundreds of thousands of Mayan inhabitants belonging to
two linguistic groups have lived there for centuries. More
recently, the crystal blue lake has attracted thousands of
tourists from around the world.
 The lake and its watershed were declared a National Park
in 1955. To date, no conservation laws are enforced in the
area.
M
SITE LOCATION
91°
18°
 Lake Atitlán is a very deep lake (340 m) of volcanic origin
located in the highlands of Guatemala at 1,562 m above
sea level.
Onion plantations
near San Pablo
Special emphasis was placed on differentiating coffee
plantations from natural forests given the importance of that
crop on the land-use dynamics for the region. Band 6
(thermal) of the images proved to be crucial in achieving this
goal.
A complete GIS system was developed for the area that
included physical and social features.
Water quality parameters were measured in situ at 28 sites
around the lake during the dry (April) and rainy (September)
seasons. Each site was located using a GPS. Samples
were brought back to the lab for more sophisticated
microbiology and chemical analyses.
Relevant socio-economic indicators for the 11 municipalities
that surround the lake were compiled from various sources.