Rodents show species-specific seed preferences but consume native and non-native seeds equally in a desert ecosystem

Novel fire regimes are expanding in North American deserts with significant potential for ecological state changes defined by the loss of native plant cover and the expansion of invasive plants. Rodents are active seed predators that can strongly influence post-fire plant community assembly in desert ecosystems. Using rodent fencing and experimental burns in a full factorial design, we examined how rodent exclusion and fire impacted the seed persistence of seven common native and three dominant invasive plant species in the Mojave Desert. We placed a known quantity of seeds in dishes in each experimental treatment plot in a randomized order. When averaged across all species, seed persistence dropped from 80% in the rodent exclusion plots to 33% in rodent allowed plots over seven days. Rodents removed some seeds of all species but had a particularly strong preference for blackbrush ( Coleogyne ramosissima Torr.) and Joshua tree ( Yucca brevifolia Engelm.) seeds. Rodents targeted native and invasive species equally, independent of the burn conditions. Rodents' seed preferences were not strongly correlated with seed size, moisture, or nitrogen content. Fire did not have a strong or consistent effect on seed removal by rodents, likely because it did not influence rodent abundance. Our results demonstrate that rodents are effective at locating and removing common native and invasive seeds in the Mojave Desert, which likely has significant implications for post-fire plant community assembly and plant invasions.