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In the article, researchers take a retrospective look at the impactof human activity on LTER Network sites spanning states fromGeorgia to New Hampshire and propose methods for measuring theeffects of such activity. The study of legacy effects is importantbecause it provides insights into how today's actions can affecttomorrow's ecological systems, says Daniel Bain, coprincipalinvestigator at the Baltimore Ecosystem Study LTER Network site andan assistant professor in the Department of Geology and PlanetaryScience in Pitt's Kenneth P. Dietrich School of Arts and Sciences.Bain notes that decision makers at all levels, including thosecreating policy, need historical information about ecosystems tomake more effective environmental policies. In a democracy, saysBain, a diverse group of stakeholders -- such as outdoorenthusiasts like Trout Unlimited, fiscal watchdog groups such asCommon Cause, and individual landowners -- needs this kind of datato effectively engage in the management of common resources. "Increasingly, we propose to manage our ecosystems withsophisticated and complicated strategies," Bain says."For example, we are attempting to manage agricultural runoffby changing how streams and floodplains are arranged. However,while designing these strategies, we tend to address the mostrecent impacts rather than the entire history of impacts. This canlead to wasted effort and misuse of relatively limitedresources." Legacy effects from human activities are all around us, says Bain,but few people ever give them a thought. For example, urban systemsaccumulate a lot of human-made materials, some of which have largeecological footprints and will ultimately leave a legacy. Baincites the example of lead, which has been banned from gasoline andpaint in the United States for several decades but can remain insoils for much longer periods of time. "We should be carefulabout growing food close to roads or near old houses," hecautions. In agriculture, areas that were plowed hundreds of years ago reactdifferently to contemporary acid deposition from air pollutantswhen compared with adjacent unplowed areas. Similarly, ourextensive use of cement may add substantial amounts of calcium tourban soils, although the ecological impact of this practice is notyet fully understood, Bain adds. Indeed, many landscapes that provide baseline ecological data forevaluating environmental change were structured in part by previoushuman interactions, such as settlements and agricultural practices.To make sense of the observed ecological patterns on suchlandscapes, Bain says, we must know something of the history of theprocesses acting to shape those patterns. A recent example of theneed for historical data associated with the impact of humans isthe debate over global warming and its associated climate change --the legacy of increased emissions of carbon dioxide and othergreenhouse gases over millennia, but hugely accelerated since theindustrial revolution and, especially, over the past severaldecades. Bain points out that without a systematic collection of datarecorded by the LTER Network, the broader geographical patterns oflegacy effects would be much more difficult to detect. For example,scientists have discovered that recently glaciated areas have muchless dirt accumulation than unglaciated areas. When Europeans firstarrived in the eastern United States and dramatically changed localagricultural practices, eroded soil ultimately found its way intowaterways. However, the glaciated areas produced less dirt, leavingless of an erosional signal in contrast to unglaciated areas, whichlost more dirt and left such erosional legacies as buried valleybottoms and filled harbors. "In terms of policy, themanagement of glaciated and unglaciated areas requires differentapproaches," Bain says. Nevertheless, Bain says, "although LTER sites have decades ofdata to draw from, we do not necessarily capture these changes,even with our best multidecade studies. It's hard to know what wemight have been able to understand now had the LTER Network beenestablished six or nine decades ago instead of three." Another major benefit of the LTER approach, according to Bain, isthe network of scientists that can jointly design a study, analyzethe data, and produce such synthetic work efficiently. This type ofhistorical analysis would take a small scientific team much longerto produce and perhaps be restricted to a smaller geographical andtime scale than this regional synthesis of historical humanlegacies at long-term research sites in the eastern United States,Bain emphasizes. We are high quality suppliers, our products such as Wood Circular Saw Blades Manufacturer , China Gang Rip Saw Blades for oversee buyer. To know more, please visits Diamond Scroll Saw Blade.
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