摘要:Major threats to freshwater ecosystems in the Andean-Amazon
region include agriculture, point and nonpoint source pollution,
hydroelectric dams, oil extraction, mining and road building, yet little
is known about the baseline values and current state of rivers
and streams, or how expanding urban, industrial and agricultural
activities could affect and change these freshwater ecosystems and
their diversity. Therefore, there is a need to understand physicochemical
parameters at the basin scale in many large river systems
in the Andean-Amazon such as the Napo River, a world biodiversity
hotspot. Establishing baselines for these parameters under less
developed conditions will be impossible after development in the
watersheds increases and hydroelectric projects reach completion.
In addition to collecting data to fill in information gaps in geology,
vegetation, disturbance, and other parameters that influence water
quality, it is important to use existing data in the Napo to predict
chemical parameters throughout the watershed to set a baseline
from which deviations from development and climate change can
be assessed and to guide data collection efforts. In this study, we
provide the first basin-wide estimates of physicochemical parameters
(pH, conductivity, dissolved oxygen and temperature) for the
entire Napo River Basin using a recently developed geostatistical
technique called top kriging. Basin-wide predictions aligned well
with observed values and a model validation test showed a strong
goodness-of-fit for parameter estimates. Furthermore, our predictions
aligned well with observed values from independent datasets
from the Napo Basin. These predictions could be useful in developing
water quality reference baselines for the basin and for monitoring
relative changes to parameters, assist in the identification of
priority areas within the basin for management and conservation
efforts, direct future research, and be applied in other data-scarce
basins in remote regions worldwide.