Watershed Buffering of Legacy Phosphorus Pressure at a Regional Scale:A Comparison Across Space and Time
| Autor: | Elena M. Bennett, A. S. Kusmer, Roxane Maranger, Jean-Olivier Goyette, Paul J. A. Withers, Graham K. MacDonald |
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| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
0106 biological sciences
Hydrology Watershed 010504 meteorology & atmospheric sciences Ecology Phosphorus chemistry.chemical_element Flux 15. Life on land 010603 evolutionary biology 01 natural sciences 6. Clean water Hydrology (agriculture) chemistry 13. Climate action Environmental Chemistry Environmental science Water quality Agricultural productivity Scale (map) Ecology Evolution Behavior and Systematics 0105 earth and related environmental sciences |
| Popis: | 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. |
| Databáze: | OpenAIRE |
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