Population dynamics and diversity of typical steppe grasshoppers in response to long-term grazing

Herbivores play a vital role in grassland biodiversity and ecosystem functioning, with their interactions significantly influencing ecosystem dynamics and stability. However, the impact of insects-especially grasshoppers-on plant diversity under typical steppe grazing conditions remains poorly understood. This study investigated the effects of grazing intensity on both plant and grasshopper diversity, as well as their interrelationships. Using sweep net trapping, we assessed grasshopper abundance and richness to examine how these populations respond to grazing intensity, seasonal variation, and plant biological characteristics. A total of 2540 grasshoppers were collected, belonging to 4 families, 6 subfamilies, and 8 species. As grazing intensity increased, grasshopper populations exhibited a triphasic dynamic: an initial increase, followed by a decline, and then a subsequent rise. Grazing's effect on biodiversity appeared as a slight initial increase that gradually stabilized. Environmental factors, particularly temperature-closely linked to grasshopper development-also significantly influenced grasshopper abundance and diversity. By exploring the relationship between large and small herbivores, this study identifies patterns through which grazing affects grasshopper populations and clarifies grasshopper-plant interactions. These findings are crucial for predicting grasshopper population dynamics and improving grazing management strategies to help prevent grasshopper infestations in grassland ecosystems.