Assessing hydrological connectivity for natural-artificial catchment with a new framework integrating graph theory and...

Area of Science:

• Environmental Science
• Hydrology
• Geospatial Analysis

Background:

• Anthropogenic activities modify drainage basin surface conditions, impacting pollutant transport and hydrological responses.
• Understanding human impact on hydrological connectivity is crucial for ecosystem processes, services, and biodiversity, but quantifying this at catchment scale is challenging.

Purpose of the Study:

• To develop and apply a novel framework for quantifying the impact of anthropogenic activities on hydrological connectivity at the catchment scale.
• To assess the influence of different human interventions (ditch-road networks, terraces) on hydrological connectivity.

Main Methods:

• Utilized graph theory and network analysis to quantify hydrological connectivity.
• Constructed three distinct transport networks (natural, ditch-road, terrace-dominated) using remote sensing and field data.
• Applied connectivity indexes to identify critical nodes within each network.

Main Results:

• Human intervention enhanced node connectivity and network complexity but significantly decreased overall hydrological structural connectivity.
• Ditch-road networks (N2) and terrace-dominated networks (N3) reduced critical hydrological connectivity nodes by 92.94% and 95.29%, respectively, compared to natural networks (N1).
• Ditch-road construction demonstrated a greater impact on reducing hydrological structural connectivity than terraces.

Conclusions:

• The proposed framework effectively quantifies hydrological connectivity under varying human interventions at the catchment scale.
• Findings highlight the significant negative impact of anthropogenic activities, particularly ditch-road construction, on hydrological connectivity.
• The framework can inform improved catchment management strategies for mitigating adverse effects on ecosystem processes and biodiversity.