Set the world on FYRE: Response of arthropods to grassland fires

Abstract

There is increasing effort by environmentalists to restore natural grasslands. However, most of this effort focuses solely on plants instead of other key factors that impact plants (such as animals that act as pollinators and seed dispersers). Current research on the effectiveness of restoration fails to capture the impact insects have on the ecosystem. The abundance of insects and other arthropod groups, like spiders, has serious repercussions for both pollination and sustaining the food web. One common restoration process is field burning, where land managers typically burn fields to clear old growth, return nutrients to the soil, and improve forage for animals. We analyzed the impact of field burning as a restoration method on different arthropod groups (grasshoppers, spiders, and butterflies) by matching burned sites with nearby unburned sites (16 total). Because the burning process has a delay in its effect, data was used from 2018, while the burning took place in 2017. Overall, we found a significant increase in arthropod abundance in burned sites compared to unburned sites. Increased arthropod abundance could be attributed to the concentration of nutrients in the plants post-burn. When analyzing the average abundance, however, there was strong variation in the level of abundance of the arthropod groups. This implies that other factors such as time of burn, intensity of burn, and burn frequency might influence the abundance. Understanding how land management processes impact arthropods assists in addressing low pollinator numbers.