Climate change at the ecosystem scale: a 50-year record in New Hampshire
Observing the full range of climate change impacts at the local scale is difficult. Predicted rates of change are often small relative to interannual variability, and few locations have sufficiently comprehensive long-term records of environmental variables to enable researchers to observe the fine-scale patterns that may be important to understanding the influence of climate change on biological systems at the taxon, community, and ecosystem levels. We examined a 50-year meteorological and hydrological record from the Hubbard Brook Experimental Forest (HBEF) in New Hampshire, an intensively monitored Long-Term Ecological Research site. Of the examined climate metrics, trends in temperature were the most significant (ranging from 0.7 to 1.3 °C increase over 40–50 year records at 4 temperature stations), while analysis of precipitation and hydrologic data yielded mixed results. Regional records show generally similar trends over the same time period, though longer-term (70–102 year) trends are less dramatic. Taken together, the results from HBEF and the regional records indicate that the climate has warmed detectably over 50 years, with important consequences for hydrological processes. Understanding effects on ecosystems will require a diversity of metrics and concurrent ecological observations at a range of sites, as well as a recognition that ecosystems have existed in a directionally changing climate for decades, and are not necessarily in equilibrium with the current climate.
The data presented were collected and processed by dozens of USFS employees, whose careful attention to detail was critical to maintaining the quality of this record. We are grateful to all those involved, especially Wayne Martin, Tony Federer and Jim Hornbeck. We thank Mark Green for helpful discussion regarding hydrologic trends. HBEF is now an NSF-funded Long-Term Ecological Research site, operated by the USFS Northern Research Station. This work was funded by NSF grant 0423259 to SPH, and is a contribution to the Hubbard Brook Ecosystem Study.
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