Carbon, Nitrogen, and Phosphorus Migration Process in the Watershed

The migration and transformation of carbon (C), nitrogen (N), and phosphorus (P) in watersheds are tightly coupled with ecosystem structure and function, making ecosystem restoration a critical pathway for regulating nutrient dynamics. Hydrological processes control the transport of nutrients, while biogeochemical transformations determine their retention, release, and ecological impacts. Carbon migration influences ecosystem metabolism and energy flow, nitrogen transformations regulate nutrient availability and water quality, and phosphorus transport is strongly linked to erosion and sediment processes. Degradation of watershed ecosystems—such as riparian vegetation loss, wetland shrinkage, and soil structure deterioration—often disrupts these nutrient pathways, leading to excessive nutrient export and eutrophication. Ecosystem restoration, including riparian buffer reconstruction, wetland restoration, and soil–vegetation system recovery, offers a nature-based solution to re-establish nutrient retention, transformation, and balanced cycling. Understanding how C, N, and P migration dynamics respond to restoration interventions is essential for designing targeted, effective watershed restoration strategies.

Watersheds are key spatial units for examining carbon, nitrogen, and phosphorus migration and their interactions with ecosystem processes. Natural and anthropogenic nutrient inputs are transported through surface runoff, subsurface flow, and sediment pathways, while their transformation depends strongly on ecosystem integrity. In many watersheds, ecosystem degradation alters nutrient migration thresholds, shifting systems from nutrient-limited or balanced states toward surplus accumulation and export. Such imbalances often trigger eutrophication and ecosystem decline. Ecosystem restoration has emerged as an effective approach to re-establish hydrological connectivity, enhance nutrient retention, and regulate C–N–P coupling processes. However, restoration is frequently implemented without sufficient consideration of nutrient migration dynamics, thresholds, and trade-offs. Clarifying when and where restoration should be initiated—whether in response to nutrient surplus, imbalance among C, N, and P, or loss of ecosystem buffering capacity—is crucial for improving restoration effectiveness and sustainability.

This Research Topic aims to place ecosystem restoration at the center of watershed nutrient management by linking carbon, nitrogen, and phosphorus migration dynamics with restoration design and decision-making. The specific objectives are to:
(1) identify how C, N, and P migration pathways and transformation processes respond to ecosystem degradation and restoration;
(2) determine restoration-relevant thresholds and triggers, including nutrient surplus, imbalance among C–N–P ratios, and loss of ecosystem retention capacity;
(3) evaluate how restoration measures—such as riparian buffer reconstruction, wetland restoration, soil structure improvement, and vegetation recovery—modify nutrient transport, retention, and transformation across spatial and temporal scales; and
(4) develop restoration-oriented watershed management frameworks that integrate nutrient migration modeling with adaptive restoration planning.
By explicitly linking nutrient dynamics to restoration timing, spatial targeting, and intervention type, this Research Topic seeks to advance restoration from a reactive practice to a process-informed, mechanism-based management strategy.

This Research Topic invites contributions that explicitly connect carbon, nitrogen, and phosphorus migration processes with ecosystem restoration theory, practice, and assessment. Topics of interest include, but are not limited to:
• Nutrient migration mechanisms under ecosystem degradation and restoration
• Restoration thresholds and indicators based on C–N–P dynamics
• Effects of riparian, wetland, and soil–vegetation restoration on nutrient retention and transformation
• Spatial targeting and timing of restoration interventions informed by nutrient transport pathways
• Modeling nutrient dynamics to support restoration planning and adaptive management
• Impacts of climate change on restoration effectiveness and nutrient regulation
• Nature-based solutions for reducing nutrient export and restoring watershed function
• Submissions that integrate field observations, modeling, and restoration practice are particularly encouraged.