فهرست نشریات علمی دسترسی آزاد ایران

River sand and gravel extraction is a significant pressure on tropical rivers, yet links between governance and ecological outcomes are under-measured. We assessed East Lombok, Indonesia (2019–2025) with a Before-After/Control-Impact approach, combining field water quality and macroinvertebrates with Sentinel-2 land- cover change, RUSLE erosion modeling, and a site-level Governance Intensity Index (permits, inspections, sanctions/closures, revegetation). Turbidity (30–80 NTU compared with 10–30 NTU) and TSS (20–60 mg/L compared with 5–20 mg/L) were elevated in mined reaches relative to upstream/control reaches, and dissolved oxygen was 2–3 mg/L lower during monsoon flows. Remote sensing revealed 10–20% riparian vegetation loss and 15– 30% bar expansion; RUSLE predicted a 10–25% increase in erosion risk at the catchment scale. Biotic responses were consistent: Shannon diversity decreased from ~2.0–2.5 to ~1.0–1.5, and EPT richness from 8–12 to 3–5 taxa downstream of extraction. More robust governance (higher index scores) mitigated—although not entirely—the magnitude of effect sizes for turbidity/TSS and loss of biodiversity. These results demonstrate cumulative seasonal effects that are conditioned by local governance implementation capacity, particularly enforcement consistency and post-extraction management. Existing policy instruments (licensing, riparian buffers, and post-extraction restoration) can ameliorate degradation when uniformly applied. We offer practical monitoring and management advice to help bring local governance in tropical sand-mining rivers in line with ecological protection.