ABSTRACT

Harmon
0218088
The Andrews LTER program seeks to understand the long-term dynamics of forest and river
ecosystems of the Pacific Northwest. The Central Question guiding Andrews LTER research is:
How do land use, natural disturbances, and climate change affect three key sets of
ecosystem services: carbon and nutrient dynamics, biodiversity, and hydrology? These
ecosystem services represent scientifically and socially important, tractable variables, and their
responses are posited to represent different classes of ecosystem behavior at the landscape scale.
Climate, land use, and natural disturbances are the major drivers of change in the Pacific
Northwest region. The approach used to address this question will be multi-faceted involving
retrospective analysis, time series observations, experiments, and use of simulation models for
synthesis, extrapolation in time, and interpolation in space. The principal spatial scale of
inference for LTER studies is the Andrews Forest and adjacent upper Blue River watershed, an
area of 16,000 ha. Work associated with the LTER will be coordinated with studies aimed at
regional questions. The principal temporal extent of proposed LTER studies spans the past 500
yr and to several centuries projected into the future. This proposal represents the strategic plan of
activities designed to advance science for individual disciplines, integration, and cross-site
comparisons. Thus, the Andrews LTER is used as the core of a larger set of integrated studies.
Essential long-term studies will be continued and others added to increase spatial and
temporal overlap of scales. The standard 5 LTER core activities will be addressed by work in
seven component areas: (1) climate, (2) hydrology, (3) disturbance, (4) ecophysiology,
(5) carbon and nutrient dynamics, (6) biodiversity, and (7) stream-forest interactions. In this
grant cycle, studies continue to examine the interaction of the drivers of change and responding
processes and taxa, but the conceptual emphasis will be on temporal behavior, its causes, and
its consequences for ecosystem change. We will examine temporal behavior over time scales of
days to hundreds of years focusing on: (1) modulation, (2) temporal lags, (3) spatial coherence,
(4) path dependence, (5) hysteresis, and (6) alternative stable states. Exploring these aspects of
temporal behavior help to address the Central Question by quantifying natural temporal
variability and providing insights into mechanisms that control processes. A major goal will be
to test predictive rules (i.e., hypotheses) regulating temporal behaviors. Another focus of
synthesis will be small watersheds, an important landscape unit providing opportunity for
integration of climatic, ecosystem, and hydrological processes as well as knowledge of temporal
and spatial scaling. The ultimate goal in this integration is to create a spatially 3-dimensional
(including subsurface and air flow) understanding of the temporal dynamics of the 3 states of
matter involved in biogeochemical and hydrologic cycles within a watershed. Past experiments,
long term records of climate, stream flow, nutrient exports, and vegetation change, as well as
modeling will enhance this integration effort. By understanding this key landscape unit, future
broader-scale efforts will be strengthened.
Andrews science and scientists continue to advance understanding and management of
forests and streams of the Pacific Northwest through communication with students, teachers,
policy makers, land managers, and the general public. Information management, an essential
activity for both research and education, emphasizes ease of use, increased accessibility, and
portability of many forms of information.

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