講演詳細

立地部門[Forest Environment]

日付	2026年3月18日
開始時刻	10:00
会場名	101
講演番号	I-5
発表題目	Regional Drivers of Stream Nitrate in Forested Watersheds of Kyushu Main Island Regional Drivers of Stream Nitrate in Forested Watersheds of Kyushu Main Island
所属	Kyoto University
要旨本文	Forested headwater streams provide baselines for nitrogen (N) cycling, yet controls on stream nitrate (NO__) vary across heterogeneous landscapes. Using 869 baseflow samples from forested watersheds in Kyushu, we integrated Random Forest modeling with k-means clustering to identify common and region-specific drivers of NO__. Across Kyushu, annual precipitation was the strongest negative predictor, indicating dilution and hydrological flushing, while atmospheric N deposition increased NO__ concentrations. Clustering revealed three distinct regimes: a northern urban_industrial region dominated by fuel-derived N deposition, a central region influenced by combined fuel, agricultural, and livestock sources, and a southern rural region where temperature and livestock-related deposition were the most important. Despite regional contrasts, precipitation consistently regulated stream NO__.
著者氏名	○Nay Lin Maung1 ・ Naoko Tokuchi1 ・ Yukio Komai1 ・ Soyoka Makino2 ・ Hikari Shimadera3 ・ Satoru Chatani4 ・ Kazuya Nishina4
著者所属	1Kyoto University ・ 2Fukui Prefectural University ・ 3The University of Osaka ・ 4National Institute for Environmental Studies
キーワード	Stream Nitrate, Nitrogen Deposition, Random Forest Regression, Cluster analysis, Forested Watersheds
Key word	Stream Nitrate, Nitrogen Deposition, Random Forest Regression, Cluster analysis, Forested Watersheds