In:
Limnology and Oceanography, Wiley, Vol. 54, No. 5 ( 2009-09), p. 1733-1745
Abstract:
We used multiple linear regressions across a Northeast Pacific region 56‐lake set to examine the influence of sockeye salmon spawner densities and limnological, climatic, and watershed characteristics on sediment stable nitrogen isotope (δ 15 N) and C:N signatures, geochemical proxies used in paleolimnological reconstructions of prehistoric salmon abundances. Across all sites (n = 56), sedimentary C:N was primarily related to variables reflecting allochthonous organic matter and nutrient fluxes, with 67= of the variance explained by watershed vegetation type, watershed area, mean slope, and salmon spawner densities. In a subset of sites with nutrient data (n = 41), 63= of variance in C:N was explained by precipitation and watershed vegetation type. Sediment δ 15 N was most strongly related to salmon spawner densities, but C:N and watershed area : lake area ratios explained significant residual variance (total 55=). In sites with nutrient data, salmon spawner densities, vegetation type, and spring nitrate explained 62= of the variance in d15N. Sediment C:N and δ 15 N values exhibited distinct interregional variation, typically varying inversely. Regional d15N‐salmon density relationships (regression slopes) varied strongly with total annual precipitation (r 2 = 0.89, p = 0.016, n = 5), suggesting watershed organic matter and nutrient loading vary predictably in relation to regional biogeoclimatic conditions. Our findings demonstrate that paleolimnological analyses are useful for quantitative reconstruction of past salmon densities; however, inferences regarding past salmon populations must consider the factors regulating influxes of nitrogen from watershed sources.
Type of Medium:
Online Resource
ISSN:
0024-3590
,
1939-5590
DOI:
10.4319/lo.2009.54.5.1733
Language:
English
Publisher:
Wiley
Publication Date:
2009
detail.hit.zdb_id:
2033191-5
detail.hit.zdb_id:
412737-7
SSG:
12
SSG:
14
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