@article {1885,
	title = {Radiocarbon and stable isotope geochemistry of organic matter in the Amazon headwaters, Peruvian Andes},
	journal = {Global Biogeochemical Cycles},
	volume = {21},
	year = {2007},
	note = {185aaTimes Cited:12
Cited References Count:37
},
	month = {Jun 27},
	abstract = {[1] We used delta C-13, delta N-15, and Delta C-14 to determine the sources of riverine organic matter in the Pozuzo River, a tributary of the Pachitea River located in the mountainous headwaters of the Amazon. Particulate organic matter (POM) Delta C-14 decreased downstream, suggesting that young organic matter (OM) introduced in small headwaters is respired preferentially in rivers or is diluted downstream with older material. The delta C-13 and delta N-15 of POM in headwater rivers were heterogeneous and also isotopically distinct from the main stem, suggesting that differences in landscape processes in small catchments impact the concentration and composition of POM in streams. The delta C-13 of dissolved organic matter (DOM) closely mirrored that of POM in the headwaters, with an apparent decoupling of dissolved and particulate OM in the river main stem. The delta C-13 of POM sampled in 2004 had a much different relationship with altitude than observed during previous years: In 2004, a very dry year, we observed enrichment from the headwaters to the main stem, and the opposite pattern in 2002, when rain fell heavily throughout the sampling campaign. This suggests that during dry conditions, in-stream processes ( such as resuspension or photosynthesis) may control riverine POM composition as opposed to terrestrial processes, which dominate during high runoff. Thus a decrease in runoff in Andean headwaters could result in less terrestrial POM transfer to rivers in the Andes foothills and lowland Amazon with a corresponding decrease in aquatic CO2 evasion.},
	keywords = {amino-acids, atlantic-ocean, carbon, drainage-basin, land-use, nitrogen, particulate, river system, sediments, streams},
	isbn = {0886-6236},
	doi = {10.1029/2006GB002835},
	author = {Townsend-Small, A. and Noguera, J. L. and McClain, M. E. and Brandes, J. A.}
}
@article {1828,
	title = {Impact of human activity on regional forest composition and dynamics in central New England},
	journal = {Ecosystems},
	volume = {1},
	year = {1998},
	month = {Jan-Feb},
	pages = {76-95},
	abstract = {Historical and ecological data from north-central Massachusetts suggest that widespread and intensive human disturbance after European settlement led to a shift in forest composition and obscured regional patterns of species abundance. A paleoecological approach was required to place recent forest dynamics in a long-term context. Pollen and charcoal data from 11 small lakes in north-central Massachusetts were used to reconstruct local vegetation dynamics and fire histories across the region over the past 1000 years. The sites are located across an environmental gradient. Paleoecological data indicate that prior to European settlement, there was regional variation in forest composition corresponding to differences in climate, substrate, and fire regime. Oak, chestnut, and hickory were abundant at low elevations, whereas hemlock, beech, sugar maple, and yellow birch were common at high elevations. Fire appears to have been more frequent and/or intense at lower elevations, maintaining high abundances of oak, and archaeological data suggest Native American populations were greater in these areas. A change in forest composition at higher elevations, around 550 years before present, may be related to the Little Ice Age (a period of variable climate), fire, and/or activity by Native Americans, and led to regional convergence in forest composition. After European settlement, forest composition changed markedly in response to human disturbance and there was a sharp increase in rates of vegetation change. Regional patterns were obscured further, leading to homogenization of broad-scale forest composition. There is no indication from the pollen data that forests are returning to pre-European settlement forest composition, and rates of vegetation change remain high, reflecting continuing disturbance on the landscape, despite regional reforestation.},
	keywords = {awenda provincial park, eastern north-america, european settlement, forest dynamics, history, human disturbance, lake sediment, land-use, new england, paleoecology, patterns, rates of change, united-states, vegetation dynamics},
	isbn = {1432-9840},
	author = {Fuller, T. L.  and Foster, D. R.  and McLachlan, T. S.  and Drake, N.}
}
