Characterization and intervention impacts on litter across public land types in Northern Idaho

Litter in recreational areas presents a growing management challenge as public land visitation increases, yet it remains critically understudied compared to urban and marine environments. This study provides the first systematic characterization of litter composition and accumulation patterns in US inland recreational campgrounds, examining four Idaho State Parks and one national forest site during the 2021 camping season. We collected and analyzed 4834 litter items (13.5 kg) from 42 campsites and 3-day use areas, revealing a distinctive waste profile that differs markedly from other environments: plastic comprised 78.6% of litter, substantially exceeding proportions found in roadways and traditional waste streams. Critically, we demonstrate that campgrounds support urban-level population densities (median 4252 people/km²) yet maintain remarkably low litter accumulation rates (2.13-2.18 kg/km²/day) compared to urban settings. This study is the first to quantify the pivotal role of volunteer camp hosts in litter management, finding they removed an estimated 111,150 pieces (> 277 kg) annually from Idaho State Parks alone, representing over $171,600 in cost savings versus paid labor. In contrast, day use areas without dedicated volunteer cleaning exhibited significantly higher litter levels, establishing volunteer presence as a critical variable in recreational litter management. Our findings challenge assumptions about the inevitability of litter accumulation in high-density recreational settings and provide the first evidence-based framework for volunteer-driven litter management strategies in resource-constrained public land agencies.