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Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Watershed Buffering of Legacy Phosphorus Pressure at a Regional Scale
T2 - A Comparison Across Space and Time
AU - Kusmer, A. S.
AU - Goyette, J.-O.
AU - MacDonald, G. K.
AU - Bennett, E. M.
AU - Maranger, R.
AU - Withers, P. J. A.
N1 - The final publication is available at Springer via http://dx.doi.org/10.1007/s10021-018-0255-z
PY - 2019/1
Y1 - 2019/1
N2 - Phosphorus (P) plays a crucial role in both agricultural production and water quality. There has been growing recognition of the importance of ``legacy'' P (surplus P that has accumulated in watersheds over time) for understanding contemporary water quality outcomes; however, little is known about how different watersheds respond to cumulative pressures from surplus P. The ``buffering capacity'' concept describes the ability of watersheds to attenuate P loading to surface waters by retaining P inputs over time. To explore the role of various watershed characteristics in buffering capacity, we used historic P data to calculate indices describing long- and short-term buffering for 16 large watersheds in southern Quebec, Canada, across a 30-year time span (1981--2011). We examined the correlation between these buffering capacity indicators and a set of key geochemical, hydrological, landscape and socio-ecological variables that we hypothesized could influence P buffering dynamics. Both short- and long-term buffering metrics were most strongly correlated with hydrological characteristics. Riverine TP flux across the watersheds was most strongly correlated with long-term buffering, which could represent a dominant influence of legacy P on contemporary riverine P flux. However, short- and long-term watershed buffering indices were not correlated with each other, suggesting distinctly different timescales and mechanisms of buffering. Combining estimates of long-term P accumulation along with biophysical characteristics of the watershed (including hydrology) explained a much greater share of the variation in riverine TP flux (R2thinspace=thinspace0.69) than biophysical characteristics alone (R2thinspace=thinspace0.36). Our findings reinforce the need to consider P buffering capacity and legacy P accumulation to help guide decision making around regional water quality targets across human-dominated landscapes.
AB - Phosphorus (P) plays a crucial role in both agricultural production and water quality. There has been growing recognition of the importance of ``legacy'' P (surplus P that has accumulated in watersheds over time) for understanding contemporary water quality outcomes; however, little is known about how different watersheds respond to cumulative pressures from surplus P. The ``buffering capacity'' concept describes the ability of watersheds to attenuate P loading to surface waters by retaining P inputs over time. To explore the role of various watershed characteristics in buffering capacity, we used historic P data to calculate indices describing long- and short-term buffering for 16 large watersheds in southern Quebec, Canada, across a 30-year time span (1981--2011). We examined the correlation between these buffering capacity indicators and a set of key geochemical, hydrological, landscape and socio-ecological variables that we hypothesized could influence P buffering dynamics. Both short- and long-term buffering metrics were most strongly correlated with hydrological characteristics. Riverine TP flux across the watersheds was most strongly correlated with long-term buffering, which could represent a dominant influence of legacy P on contemporary riverine P flux. However, short- and long-term watershed buffering indices were not correlated with each other, suggesting distinctly different timescales and mechanisms of buffering. Combining estimates of long-term P accumulation along with biophysical characteristics of the watershed (including hydrology) explained a much greater share of the variation in riverine TP flux (R2thinspace=thinspace0.69) than biophysical characteristics alone (R2thinspace=thinspace0.36). Our findings reinforce the need to consider P buffering capacity and legacy P accumulation to help guide decision making around regional water quality targets across human-dominated landscapes.
KW - phosphorus
KW - watershed
KW - agriculture
KW - historic legacy
KW - land use
KW - hydrology
KW - soil P
KW - nutrient budgets
U2 - 10.1007/s10021-018-0255-z
DO - 10.1007/s10021-018-0255-z
M3 - Journal article
VL - 22
SP - 91
EP - 109
JO - Ecosystems
JF - Ecosystems
SN - 1435-0629
IS - 1
ER -