Frequent fires eliminate fleshy fruit production

- Prescribed fire commonly is used to manage wildlife habitat.
- Fruit is a primary food source for many wildlife.
- Frequent fires may eliminate fruit production.
- Varying fire-return interval is recommended.

Frequent fire-return intervals (<3-yr) have been suggested to optimize the benefits of prescribed fire in many fire-dominated ecosystems. There are several potential ecological benefits to frequent fires, such as suppression of encroaching fire-intolerant plant species, increased reproductive allocations of native herbaceous plant species, and increased plant diversity at the stand level. However, recent literature has reported a decline in frugivorous wildlife species in frequently burned landscapes, raising concern for fire-regime effects on fruit production. Thus, an assessment of the effects fire frequency on fleshy fruit abundance is needed. In a replicated field experiment following 4 or more rotations of a 1-yr, 2-yr, and 3-yr fire-return interval, we measured fruit production each month of the growing season (i.e., May-September) in the critically threatened longleaf pine (Pinus palustris) ecosystem - an ecosystem where frequent fire intervals commonly are recommended. Compared to the 3-yr fire-return interval, cumulative understory fruit production was 99% less following a 1-yr or 2-yr fire-return interval. In fact, all of the fruit detected in 1-yr and 2-yr treatments were detected in patches of vegetation unburned by the previous fire. Additionally, no fruits were detected on any transect in the midstory and overstory strata. These results suggest that applying fire on <3-yr fire-return intervals across large land areas could have negative effects on soft mast-dependent wildlife species. Moreover, without a mosaic in fire-spread, even a 3-yr fire return interval may eliminate midstory and overstory fleshy fruit production over time. We recommend fire managers incorporate multiple fire-return intervals and firing techniques to capture the ecological benefits of variability in frequency and spatial extents in fire.