Cache sites preferred by small rodents facilitate cache survival in a subtropical primary forest, central China

Abstract

Context Scatter-hoarding rodents tend to hoard plant seeds in preferred places that facilitate seed survival, resulting in high food rewards for hoarders and a high probability of seedling establishment for plants. Aims To test the hypothesis that caches placed in rodent-preferred microhabitats, nearest-neighbour distances between caches (cache density) or cache depths have an increased chance of survival. Methods Rodent-made caches and observer-established caches of Himalayan hazelnut (Corylus ferox) seeds were tracked in a subtropical primary forest in central China. The survival of caches within rodent-preferred microhabitats, nearest-neighbour distances and cache depths were identified. Key results Rodents preferred to hoard Himalayan hazelnut seeds in microhabitats under and at the edge of shrubs, with the nearest-neighbour distance of <4.0 m, and at 2.1–4.0-cm depth. The survival times of both rodent-made caches and observer-established caches were longer within rodent-preferred microhabitats than in other habitats and increased with an increasing nearest-neighbour distance and cache depth, up to what appeared to be an optimal nearest-neighbour distance and depth. Conclusions Conditions of rodent-preferred cache microhabitats, nearest-neighbour distances and cache depths can facilitate cache survival. Implications Rodents often move plant seeds away from parent trees and bury them in shallow soil, which benefits seed dispersal and establishment of plants. The present study demonstrates that rodent-preferred cache conditions may translate into higher seed survival and a higher tendency of seeds to germinate and establish. Thus, careful management and conservation of rodent-preferred hoarding habitats may benefit seed dispersal and survival.