The purpose of this research is to examine the effects
of hydrologic and thermal change in alpine and subalpine streams
and associated wetlands in McDonald Creek watershed, Glacier National
Park. During the past seven years we have contributed significantly
to the ecological understanding of the stream continuum along the
elevation gradient of this drainage (e.g., Hauer et al. 1997, Fagre
et al. 1997, Hauer et al. 1998, Tabbachi et al. 1998, Lowe and Hauer
1999, Hauer et al 2000). The foundation of this understanding includes
detailed hydrologic and thermal monitoring, repeated measures of
nutrient concentrations and carbon dynamics, and the distribution
and abundance of stream fauna.
This project is a part of the Global Change
Operations and Conceptual Research Plan approved for Glacier
National Park (GNP) in 1990. Climate changes on
the planet during the next century are expected to have major
impacts on regional freshwater ecosystems. Although
the task of predicting future climate scenarios and resulting
biological consequences is daunting, there is general agreement
that aquatic systems will likely undergo alterations in water
quantity, water quality and thermal dynamics.
Small shifts in any of these attributes could substantially
alter the diverse and typically fragile biota occupying freshwater
habitats in pristine areas like GNP. The purpose of
this study is to address some of the questions relevant to
understanding and predicting the effects of climate change
on hydrologic processes and resulting impacts on cold water
ecosystems. We are examining the biodiversity of alpine
streams as indicators of climatic change. Global Climate
Models suggest that with the increase in green house gases
in the atmosphere, particularly during the past several decades,
the climate throughout the Rocky Mountains may become increasingly
variable with measurable change in precipitation and
temperature.
Variation in precipitation may manifest
as increased storm activity with periods of high precipitation
or as change in weather patterns with the Northern Rockies
having extended periods of draught. Likewise, variation
in temperature may occur as higher summer maximum and lower
winter minimum, thus expanding the annual range of temperatures.
The interaction of precipitation and temperature variation
may have a significant effect on stream temperature and hydrologic
flows and regime. High alpine streams appear to be extremely
sensitive to variation in snow accumulation and the rate of
snowmelt in the summer. These same streams may also
be more vulnerable to loss of snowpack and thus, transition
from being a permanently flowing stream to an ephemeral stream.
This change in state, as well as change in temperature, could
result in significant change in stream biota.
Above: A stream
being studied in Glacier National Park.
Arctopsyche grandis,
one of the insects being studied as a part of this project.
