Colorado mountains

Long term Ecological Research at the H.J. Andrews Experimental Forest (AND)

Poster Number: 
Presenter/Primary Author: 
Sherri Johnson
Michael Nelson

Over its 31-year history, the Andrews LTER (“AND”) program has expanded into a major center for knowledge and understanding of forest and stream ecosystems in the Pacific Northwest. Today, several dozen university and federal scientists use this Experimental Forest and LTER site as a common meeting ground, conducting interdisciplinary research to gain basic understanding of ecosystems and their processes and to apply this knowledge for management and policy.

The Andrews Forest Central Question, "How do land use, natural disturbances, and climate affect three key ecosystem properties: carbon and nutrient dynamics, biodiversity, and hydrology?" was developed to provide a common framework for long-term studies. Over the years, we have focused on themes and specific hypotheses that help us explore critical dimensions of the Central Question, including process-based understanding of landscape dynamics (LTER3, 1990-1996); effects of early succession on ecosystem dynamics and impact of species attributes on ecosystem dynamics (LTER4, 1996-2002); and small watershed behavior and temporal behaviors (LTER5, 2002-2008). In the current LTER grant (LTER6, 2008-2014), we are examining role of complex mountainous terrain in structuring biotic and abiotic responses to climate variability and change. 

The conceptual organization of LTER6 highlights three complementary goals. The complex terrain and dense canopy cover of our site profoundly influence biodiversity, ecosystem processes and services, and their likely responses to climate variability and change. Therefore, in Goal I we are developing a deeper understanding of the Andrews Central Question in the context of complex terrain. We are exploring trends in long term records of hydrology, climate, biogeochemistry and stream temperature as well as starting new study of phenological responses of plants, insects and birds to existing climatic variation across the forest. We are calculating carbon budgets in airsheds and watersheds and as part of our Goal II, we are applying this mechanistic understanding to evaluate potential future responses to change scenarios. In Goal III we are expanding our inquiry to consider the Andrews Forest as a coupled natural/human system.

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Background Photo by: Nicole Hansen - Jornada (JRN) LTER