TY - GEN A1 - Wilcke, Wolfgang A1 - Leimer, Sophia A1 - Peters, Thorsten A1 - Emck, Paul A1 - Rollenbeck, Rütger A1 - Trachte, Katja A1 - Valarezo, Carlos T1 - The nitrogen cycle of tropical montane forest in Ecuador turns inorganic under environmental change T2 - Global Biogeochemical Cycles N2 - [1] Water‐bound nitrogen (N) cycling in temperate terrestrial ecosystems of the Northern Hemisphere is today mainly inorganic because of anthropogenic release of reactive N to the environment. In little‐industrialized and remote areas, in contrast, a larger part of N cycling occurs as dissolved organic N (DON). In a north Andean tropical montane forest in Ecuador, the N cycle changed markedly during 1998–2010 along with increasing N deposition and reduced soil moisture. The DON concentrations and the fractional contribution of DON to total N significantly decreased in rainfall, throughfall, and soil solutions. This inorganic turn of the N cycle was most pronounced in rainfall and became weaker along the flow path of water through the system until it disappeared in stream water. Decreasing organic contributions to N cycling were caused not only by increasing inorganic N input but also by reduced DON production and/or enhanced DON decomposition. Accelerated DON decomposition might be attributable to less waterlogging and higher nutrient availability. Significantly increasing NO3‐N concentrations and NO3‐N/NH4‐N concentration ratios in throughfall and litter leachate below the thick organic layers indicated increasing nitrification. In mineral soil solutions, in contrast, NH4‐N concentrations increased and NO3‐N/NH4‐N concentration ratios decreased significantly, suggesting increasing net ammonification. Our results demonstrate that the remote tropical montane forests on the rim of the Amazon basin experienced a pronounced change of the N cycle in only one decade. This change likely parallels a similar change which followed industrialization in the temperate zone of the Northern Hemisphere more than a century ago. KW - nitrogen deposition KW - climate change KW - dissolved organic nitrogen KW - nitrogen turnover KW - ecosystem solutions Y1 - 2013 U6 - https://doi.org/10.1002/2012GB004471 VL - 27 IS - 4 SP - 1194 EP - 1204 ER - TY - GEN A1 - Leimer, Sophia A1 - Berner, Doreen A1 - Birkhofer, Klaus A1 - Boeddinghaus, Runa S. T1 - Land-use intensity and biodiversity effects on infiltration rates and hydraulic conductivity of grassland soils in southern Germany T2 - Ecohydrology N2 - Evidence from experimental and established grasslands indicates that plant biodiversity can modify the water cycle. One suspected mechanism behind this is a higher infiltration capacity (νB) and hydraulic conductivity (K) of the soil on species-rich grasslands. However, in established and agriculturally managed grasslands, biodiversity effects cannot be studied independent of land-use effects. Therefore, we investigated in established grassland systems how land-use intensity and associated biodiversity of plants and soil animals affect νB and K at and close to saturation. On 50 grassland plots along a land-use intensity gradient in the Biodiversity Exploratory Schwäbische Alb, Germany, we measured νB with a hood infiltrometer at several matrix potentials and calculated the saturated and unsaturated K. We statistically analysed the relationship between νB or K and land-use information (e.g., fertilising intensity), abiotic (e.g., soil texture) and biotic data (e.g., plant species richness, earthworm abundance). Land-use intensity decreased and plant species richness increased νB and K, while the direction of the effects of soil animals was inconsistent. The effect of land-use intensity on νB and K was mainly attributable to its negative effect on plant species richness. Our results demonstrate that plant species richness was a better predictor of νB and K at and close to saturation than land-use intensity or soil physical properties in the established grassland systems of the Schwäbische Alb. Y1 - 2021 U6 - https://doi.org/10.1002/eco.2301 SN - 1936-0584 SN - 1936-0592 VL - 14 IS - 6 ER -