The early stage of seedling establishment is critical to successful ecological restoration and reforestation, and it is partially influenced by herbivory. Aerial vertebrate predators, including birds and bats, can affect plant growth by controlling phytophagous insects. This study explored the effects of excluding birds and bats on the arthropod community during the initial stages of reforestation plots planted with Dipterocarpus alatus in deciduous dipterocarp forest using an exclusion experiment. We hypothesized that birds and bats negatively affect the density and biomass of large-sized arthropods (≥ 1 cm), which are their potential prey, and that excluding these predators may affect seedling growth and leaf damage. The density and biomass of large arthropods significantly increased in the permanent exclosures compared to the control group. No significant difference between the nocturnal and diurnal exclosures was observed. Top-down effects on the biomass of large-sized phytophagous and predatory arthropods were pronounced during the dry season, coinciding with the presence of migratory insectivorous birds. Mesopredator release primarily driven by ants compensated for the absence of birds and bats, preventing immediate increases in herbivory or impacts on seedling growth. These findings highlight the importance of ecological redundancy among predator communities in maintaining herbivory control. Promoting diverse habitats that support both invertebrate and vertebrate predators may enhance the long-term resilience and effectiveness of pest control in ecological restoration efforts.

The effects of insect-resistant transgenic cotton on the diversity of arthropod communities in cotton fields in North China were investigated during 2000–2001. The field experiments were conducted in non-insecticide treated plots of transgenic cotton lines (SGK321, a transgenic cotton variety carrying Cry1A+CpTI genes; GK12, a transgenic cotton variety carrying the Cry1Ac gene) and their conventional parent varieties (Shiyuan 321 and Shimian 3, respectively), and in sprayed plots of the parent varieties where pyrethroid insecticides were used regularly against the cotton bollworm. All the arthropods were sucked up using a portable suction device and identified to species wherever possible. They were later sorted into guilds (pests, natural enemies and neutral arthropods) for diversity analysis using the method of Shannon's index. The diversity of arthropod communities in transgenic cotton plots was similar to that in conventional cotton fields without spraying, but Shannon's index for total arthropod community and the neutral arthropod guild in Bt cotton fields were significantly higher than those in sprayed plots in the mid and late growing stages of cotton. It is concluded that planting of Bt cotton could increase the stability of arthropod communities in cotton ecological systems and benefit the management of insect pests in cotton.