DOI: 10.5061/dryad.tqjq2bw0t
title: Data: Prescribed fire enhances seed removal by ants in a Neotropical savanna

description: Seed dispersal and predation by animals often drive plant regeneration. In
 tropical savannas, such as the Cerrado of Brazil, fire is also a key
 process in ecosystem dynamics, consuming the lower vegetation strata and
 killing wildlife, but how fire affects seed-animal interactions is
 virtually unknown. We investigated the effects of prescribed fires on the
 removal of diaspores from Miconia rubiginosa and sunflower Helianthus
 annuus in Cerrado from southeast Brazil. Using plots burned one month or
 one year before sampling and unburned controls, we assessed the effect of
 prescribed fire on microhabitat structure and diaspore removal by
 vertebrates and ants. Covered microhabitats experienced higher seed
 removal by vertebrates than open microhabitats, but microhabitat features
 did not influence seed removal by ants. Prescribed fire did not change the
 total amount of seed removal, and ants were responsible for most removals
 in burned and control plots. However, fire increased the importance of
 ants as agents of removal compared to vertebrates. These changes were
 probably mediated by changes in microhabitat cover. It is likely that
 species whose seeds are often preyed upon by vertebrates benefit from fire
 to escape predation, while the opposite would be true for those removed by
 granivorous ants. By changing microhabitats composition and frequency of
 seed removal by different agents, fire may create pulses of opportunities
 for certain plant species to increase their populations and enlarge their
 spatial distribution, while constraining others. However, how different
 fire intensities and frequencies influence seed fate of different species
 is still to be investigated.
description: Data collection was carried out in a protected area of Cerrado in
 southeastern Brazil. To investigate the effect of prescribed fire on seed
 removal we performed removal experiments with seeds of Miconia rubiginosa
 and sunflower. Sampling was done at three sites &gt; 1.7 km apart.
 Each site has areas subjected to prescribed burning and controls where we
 established sampling transects. Each transect contained four seed removal
 stations 10 m apart from each other. Each removal station received two
 paired-treatments ca. 30 cm from each other: an open control accessible to
 all animals and a selective exclosure allowing only ant access to the
 seeds. We placed 10 seeds of each species per treatment combination. After
 24 hr, we counted the number of seeds removed or preyed on at the
 spot. To test the impact of fire in microhabitat
 variables and a cascading effect in seed removal, we measured microhabitat
 features of canopy and ground layer vegetation around all seed removal
 stations. To evaluate the density of the ground layer vegetation, we held
 a graduated pole vertically above ground in four points (north, south,
 east and west), one meter from where the seeds were placed. We counted the
 number of vegetation intersections at two levels of the pole: from 0 to
 0.5 m and from 0.5 to 1 m from the ground. To estimate canopy and ground
 layer cover we visually assigned an index for plant cover scored from 0 to
 4, as 0 = uncovered, 1 = up to 25% cover, 2 = 25 to 50% cover, 3 = 50 to
 75% cover and 4 = over 75 % cover. Canopy cover (percentage) was estimated
 within a 5 m radius centred at the removal station, while for the ground
 layer a 2 m radius was considered. Additionally, we counted the total
 number of trees (&gt;10 cm DBH) and shrubs (woody plants branched up
 to 1 m above ground) within a 2 m radius from the removal
 stations.
description: There are no missing
 values. Please see Readme.txt file for more details about
 variables.