文章基本信息

标题：Catchment-scale contribution of invasive nitrogen fixing shrubs to nitrate leaching: a scoping study
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作者：NWH Mason ; PL Mudge ; D Palmer 等
期刊名称：Journal of the Royal Society of New Zealand
印刷版ISSN：0303-6758
电子版ISSN：1175-8899
出版年度：2016
卷号：46
期号：2
页码：85-102
DOI：10.1080/03036758.2015.1127261
语种：English
出版社：Taylor & Francis Group
摘要：Woody nitrogen (N) fixers are known to fix atmospheric N at very high rates. However, N leached from woody N fixers is rarely accounted for in catchment nutrient budgets. We conducted a scoping study to determine the potential impact of the invasive N fixer gorse (Ulex europaeus) on water quality in an agricultural catchment in New Zealand. With current gorse cover (596 ha) our model-based leaching estimates suggest that gorse accounts for 1.7%–2.4% of total N leaching in the catchment. This is equivalent to leaching from 1200–1800 ha of pasture (averaged across both dry stock and dairy land uses). In our worst-case scenario, with gorse covering over 5000 ha, we estimate that N leaching from gorse would account for 12%–25% of the catchment total. The expected increase in N leaching under this scenario is equivalent to leaching for 9000–14000 ha of pasture, suggesting that gorse could significantly constrain capacity for agricultural expansion or intensification if a cap on N loads is imposed in the catchment. These results show that leaching from gorse is probably much higher than currently assumed. Further, land use policies aiming to abandon marginal land may cause a net increase in leaching if large areas of abandoned land are colonised by gorse.
关键词：Broom;ecosystem services;gorse;land use change;land use scenarios;water quality