Seed Predation Research Articles

Temperature influences postdispersal predation of weed seeds

Temperature is a key factor for the living organisms on earth. It influences weed management practices, either directly or indirectly. Field experiments were conducted to determine the effect of temperature on the postdispersal seed predation of four important weed species (Cuscuta compestris, Stellaria media, Taraxacum officinale and Veronica persica) in two lucerne fields in Mashhad and Chenaran, north‐eastern Iran. These two cities have the same climate: temperate and cold alpine but the temperature varies between them. Wire mesh cages were used to determine the relative importance of birds in predation and pitfall traps were used to detect the species and the activity density of invertebrate predators. The results showed that the predation preference of different weed species was significantly different between and within fields. Seed predation fluctuated widely throughout the sampling periods, matching the periodic forage harvest and regrowth cycle of lucerne. Despite the level of seed predation fluctuating, it declined toward the last sampling periods. Using wire mesh exclusion cages showed no significant effect of birds on weed seed predation in both fields. Ants, crickets and carabid beetles were the invertebrate seed predators that were caught in the pitfall traps. There were significant correlations between the mean temperature and predator activity densities and also between the predated seeds and the mean air temperature in both locations. The results of this study indicate the significant effect of temperature on postdispersal weed seed predation. Therefore, with respect to climate change and increasing global warming, it would be possible to focus on postdispersal seed predation in weed management in the future.

Pre-Dispersal Seed Predation in a Species-Rich Forest Community: Patterns and the Interplay with Determinants.

Pre-dispersal seed predation (PDSP) is commonly observed in woody plants, and recognized as a driver of seed production variability that is critical for successful regeneration. Earlier studies on PDSP and its determinants were mostly species specific, with community-level PDSP rarely estimated; and the interactions between the temporal variability of seed production and PDSP remain elusive. In this study, the community seed rain of woody plants in a mixed evergreen-deciduous broadleaf forest was monitored for seven years. We examined predation on collected seeds and analyzed the determinants of PDSP. PDSP was recorded in 17 out of 44 woody plant species, and three-quarters of PDSP was due to insect predators. Annual seed production varied substantially at community level, reversely linked with the temporal variation of PDSP rate. The PDSP rate was biased regarding fruit types, and being significantly correlated with seed mass when using phylogenetic independent contrasts (PICs) or without taking into account phylogenetic relations, especially for nuts. PDSP rate was also negatively correlated with seed density, showing a threshold-related predator satiation effect. The community-level PDSP rate was primarily determined by tree height, fruit type, and interannual variation of seed production and seed mass. Our analysis revealed a causal link between seed production and the dynamics of PDSP rate at the community level. The predator satiation effect was primarily contributed by the dominant species, whereas the rare species seemed to apply a distinct “hide-and-seek” strategy to control the risk of PDSP. The mechanistic difference of seed production between the common and rare species can shed new light on species coexistence and community assembly. Long-term monitoring of both seed rain and seed predation is required for understanding the ecological and evolutionary implications of species regeneration strategies in a species-rich forest community.

Presence and Intensity of Predispersal Seed Predation in a Rare Plant in Response to Habitat Quality and Population Metrics

ABSTRACT: Predispersal seed predation can be detrimental for any plant, but especially for rare plants. In this study, we examined the relationship of predispersal seed predation to different habitat types (i.e. open, semi shaded, and shaded), population size, and population density for Synthyris bullii, a rare Midwestern US endemic plant. In 2009, 2010, and 2011, a total of 18 populations were sampled across the range of Synthyris bullii. Fruit damage and predispersal seed predation were determined from up to 20 randomly collected infrutescences from each population. Predispersal seed predation had an impact on reproductive output and varied by habitat type. In addition, predispersal seed predation varied by population size and population density. Understanding the effects of predispersal seed predation on rare plants can be crucial for maintaining stable populations and developing better conservation and management strategies.

Spatial scale affects seed predation and dispersal in contrasting anthropogenic landscapes

Seed predation and dispersal can have strong, albeit opposing effects on plant communities and their extent depends on interactions between seeds and their vectors (abiotic factors or different animal taxa). We assume that vectors, due to their specific requirements, act at different spatial scales and seed-vector interactions might differ greatly between landscapes. So far, it remains largely unclear, how the interaction between seeds and their vectors affects the degree of seed predation and dispersal in novel anthropogenic landscapes. We expect changes in patterns either at the landscape scale (urban vs. rural areas), habitat scale (habitat heterogeneity) or microhabitat scale (vegetation variability).We assessed seed predation and dispersal of two seed species by rodents, earthworms, other invertebrates and rain in cafeteria experiments in urban gardens and rural field margins and implemented generalized mixed effect models to test the effect of spatial scales and other environmental variables.Seed predation and dispersal were generally low and similar patterns emerged when the same vector facilitated the function. Overall, predation and dispersal were similar in urban and rural areas but when differentiating between vectors, scale effects were evident. Seed predation by rodents and earthworms was affected at the landscape scale, seed predation by other invertebrates increased with higher habitat heterogeneity and seed dispersal by rain was negatively affected at the microhabitat scale through increased plant cover.We show that one vector can facilitate the contrasting two functions, seed predation and dispersal, simultaneously, resulting in similar patterns at a specific spatial scale. However, different vectors might lead to contrasting patterns for the same function, depending on the spatial scale. This needs to be considered especially in anthropogenic areas, where ecosystem management decisions are also made at different spatial scales from private garden owners to landscape planning committees.

Pondberry (Lindera melissifolia, Lauraceae) seed and seedling dispersers and predators

Pondberry (Lindera melissifolia(Walter) Blume) is an endangered dioecious, clonal shrub that grows in periodically flooded forests of the southeastern United States. The probability of survival of dispersed pondberry seeds and new germinants is unknown, but few seedlings are noted in the forest. This study was undertaken to: (1) identify herbivores and predators of pondberry seeds and seedlings, (2) record the fate of pondberry seeds and seedlings after simulated dispersal in areas with lower and higher understory cover, and (3) calculate the probability of seed survival in the two cover types. The study was conducted in or near the Delta National Forest and the Delta Experimental Forest, MS. Pondberry seed and seedling plots were established at sites with high or low cover. Video cameras with infrared illumination were set up to monitor animal visitors to the plots. Image analysis indicated that swamp rabbits (Sylvilagus aquaticus (Bachman)) and wood rats (Neotoma floridana Ord) cut or ate seedlings, while other animals visited the plots without damaging seedlings. Numerous bird species and mammals visited the seed plots and some were filmed eating seeds. Pondberry seeds exposed in open habitats had a significantly higher survival rate than those exposed in habitats with more herbaceous and woody understory cover. The novelty and quality of the temporal data collected via video monitoring indicate the importance of this method in collecting data that are not otherwise available on endangered and rare species.

Patch size, shape and edge distance influence seed predation on a palm species in the Atlantic forest

Seed predation is an important ecological process that affects the abundance, diversity and distribution of plant species, and it is known to be influenced by defaunation and forest fragmentation. Most studies on seed predation in human‐modified landscapes do not take into account the different spatial scales in which this process operates. In this study, we evaluated how variables at three distinct spatial scales affected the seed predation of a palm that provides a keystone resource to the frugivore community, the queen palmSyagrus romanzoffiana. Thirteen landscapes that vary in forest cover, number of fragments and patch sizes were sampled in the Brazilian Atlantic forest. We also evaluated the contribution of the three main groups of seed predators: squirrels, terrestrial rodents and invertebrates. Our results indicate that seed predation is more affected by fragment and local variables than by landscape influences. In addition, the size of the fragment, its shape and the distance from the nearest forest edge were the main predictors of the proportion of predated seeds. Moreover, the two main seed predators (squirrels and invertebrates) responded to the same fragment and local variables. Because most of the Atlantic forest consists of small fragments, we expect that the seed predation of this keystone palm should be high in most of its distribution, with potential consequences for the frugivore community.

Predação de sementes por insetos em três espécies simpátricas de Copaifera L. (Fabaceae)

Seed predation by insects in three sympatric species of Copaifera L. (Fabaceae). This study aimed to evaluate the predation rate on seeds and compare fruit length, width, and weight in Copaifera sabulicola J. Costa & L.P. Queiroz, Copaifera luetzelburgii Harms, and Copaifera depilis Dwyer, as well as identify the insects predating on seeds. For the analysis, 900 mature fruits were sampled for each Copaifera species, totaling 2,700 fruits collected from 90 plants in the municipality of Barreiras, Bahia, Brazil. Greater fruit width and length were observed in C. sabulicola. Out of the 2,700 seeds analyzed, 46% were healthy, 41.85% were damaged by insects, and 12.14% were not healthy. The highest predation rate was observed in C. depilis (52.88%) and C. luetzelburgii (46.33%). The correlation coeficient between predation rate and biometrics data was not signiicant. A total of 1,802 Insecta specimens were found associated with Copaifera fruits. The Coleoptera order showed higher abundance and two genera were identiied in this order, Rhinochenus brevicollis Chevrolat, 1871 (Curculionidae) and Apion sp. Herbst, 1797 (Brentidae). Lepidoptera larvae were also detected feeding on fruits.

Effect of an invasive plant and moonlight on rodent foraging behavior in a coastal dune ecosystem.

Understanding how invasive plants may alter predator avoidance behaviors is important for granivorous rodents because their foraging can trigger ripple effects in trophic webs. Previous research has shown that European beach grass Ammophila arenaria, an invasive species in coastal California, affects the predation of other seeds by the rodents Microtus californicus, Peromyscus maniculatus, and Reithrodontomys megalotis. This may be due to lower perceived predation risk by rodents foraging in close proximity to the cover provided by Ammophila, but this mechanism has not yet been tested. We examined the perceived predation risk of rodents by measuring the ‘giving up density’ of food left behind in experimental patches of food in areas with and without abundant cover from Ammophila and under varying amount of moonlight. We found strong evidence that giving up density was lower in the thick uniform vegetation on Ammophila-dominated habitat than it was in the more sparsely and diversely vegetated restored habitat. There was also evidence that moonlight affected giving up density and that it mediated the effects of habitat, although with our design we were unable to distinguish the effects of lunar illumination and moon phase. Our findings illustrate that foraging rodents, well known to be risk-averse during moonlit nights, are also affected by the presence of an invasive plant. This result has implications for granivory and perhaps plant demography in invaded and restored coastal habitats. Future research in this system should work to unravel the complex trophic links formed by a non-native invasive plant (i.e., Ammophila) providing cover favored by native rodents, which likely forage on and potentially limit the recruitment of native and non-native plants, some of which have ecosystem consequences of their own.

Observations of seedeaters from Djibouti

Observations of seedeaters from Djibouti

When losing your nuts increases your reproductive success: sandalwood (Santalum spicatum) nut caching by the woylie (Bettongia penicillata)

To regenerate sandalwood (Santalum spicatum) stands in south-western Australia it is necessary to understand the complex relationship between woylies (Bettongia penicillata ogilbyi) and sandalwood. Sandalwood requires a seed disperser for successful recruitment and in the past the critically endangered woylie played an important role in dispersing and caching seeds, but it is not clear whether this mutualistic and antagonistic relationship is beneficial to regeneration efforts. An enclosure in a woodland and 46Scandium-labelled seeds, enabled study of the in situ predation of seeds, caching, the fate of cached seeds, the detection of cached seeds and predation of germinated seeds. Woylies preferentially cached sandalwood, then S. acuminatum seeds, before any interest was shown in Acacia acuminata and Gastrolobium microcarpum seeds, which were virtually all eaten in situ. Of a further 500 radiolabelled and individually numbered sandalwood seeds deployed, 42.2% were eaten in situ, 20.8% had an unknown fate and 37% were cached, with some seeds being recached up to four times. After nine months, only four cached seeds remained undisturbed. Olfaction appeared to be the primary method of cache detection. To examine the recruitment rate of cached seeds, the fate of 89 transplanted sandalwood seedlings at two study sites was followed. After one month 38% were intact and growing, but half of the transplanted seedlings were dug up and the remaining endosperm was eaten in situ or taken away. The results highlight the potential of providing seed supplies, including sandalwood seeds and seeds of their hosts, to seed-dispersal marsupials for passive ecosystem repair.

Weed seed choice by carabid beetles (Coleoptera: Carabidae): Linking field measurements with laboratory diet assessments

Carabid beetles could potentially provide a number of ecosystem services in arable fields, including the regulation of weeds by eating seeds. Spatio-temporal variability in the incidence of predation combined with a limited understanding of the interactions between carabids and seed predation, currently limits our ability to assess the effectiveness of this service. We carried out a long-term field study of carabid communities and the incidence of predation of the seeds of 5 species of weeds and laboratory cafeteria choice-tests to quantify the preferences of the most abundant species of seed-eating carabid for the seeds of 10 species of weeds. The field study revealed important temporal variation both in carabid activity-density and seed predation, with the seed of Viola arvensis and Capsella bursa-pastoris being particularly preferred by the carabids. The laboratory cafeteria tests confirmed the predation preferences measured in the field, in showing strong preferences by both Pterostichus melanarius and Pseudoophonus rufipes for the seed of V. arvensis. The percentage predation of the seed of V. arvensis was associated with the activity-density of carabids, while that of the seed of C. bursa-pastoris was not. Integrating laboratory-measured daily consumption rates, per carabid taxa, into models improved the ability to predict the intensity of predation of the seed of V. arvensis based on the composition of carabid communities.

Effect of Cry3Bb Bt Corn and Tefluthrin on Postdispersal Weed Seed Predation

Indirect effects of insect control strategies on weed populations are important to consider when developing robust integrated pest management strategies. Weed seed predation rates were investigated in corn managed under three contrasting treatments based on control practices for corn rootworm: (1) the transgenic crop Cry3Bb Bt corn, (2) the broad-spectrum insecticide tefluthrin, and (3) no insecticide control. This 2-yr field study conducted near Ithaca, NY, involved quantifying seed loss from velvetleaf, common lambsquarters, and giant foxtail in arenas with and without vertebrate exclosures. Velvetleaf and giant foxtail were unaffected by the insecticide treatment; however, average seed predation of common lambsquarters was lower in both the Bt corn (11.9%) and insecticide-treated plots (11.8%) compared with control plots (17.5%) that did not receive any insecticide. Seed predation of common lambsquarters was not affected by the vertebrate exclosure. Lower seed predation in the transgenic Bt corn and insecticide treatments was likely due to nontarget effects on carabids (Coleoptera: Carabidae). Although the reduction in seed predation was modest and limited to only one of the three weed species tested, our results highlight the need for greater risk assessment that includes the ecosystem service of weed seed predation when considering insect pest management options.

Post-dispersal predation of Pinus pinaster Aiton seeds: key factors and effects on belowground seed bank

Seed bank dynamics constitute a pool of natural regeneration, a complex and key process for stand persistence. The present work analyzes post-dispersal predation on a Pinus pinaster Ait. (maritime pine) belowground seed bank. The study was carried out at the experimental site of Mata de Cuellar (Segovia, central Spain), where an integrated analysis of maritime pine regeneration has been underway since 2004. Seed predation was monitored every month from 2010 to 2013. A generalized linear model was fitted using “next spring seed density” as the response variable and seed rain, micro-site conditions and annual climate variability as explanatory variables. Seed rain, distance to the nearest stump, basal area and Walter’s drought index, along with percentage cover of herbaceous species, pine needle litter and shrub species, had significant positive effects. The number of neighboring trees had a significant negative effect on seed density. These results demonstrate how seed rain, summer drought and micro-site conditions are crucial to understand the effects of predation on the belowground seed bank. Though greater than null, the final seed bank might be insufficient for successful natural regeneration due to high mortality caused by difficult germination and establishment conditions.

Crop damage of Eriotheca gracilipes (Bombacaceae) by the Blue-Fronted Amazon (Amazona aestiva, Psittacidae), in the Brazilian Cerrado.

Seed predation has major effects on the reproductive success of individuals, spatial patterns of populations, genetic variability, interspecific interactions and ultimately in the diversity of tree communities. At a Brazilian savanna, I evaluated the proportional crop loss of Eriotheca gracilipes due the Blue-Fronted Amazon (Amazona aestiva) during a fruiting period. Also, I analyzed the relationship between proportional crop loss to Amazons and both fruit crop size and the distance from the nearest damaged conspecific. Trees produced from 1 to 109 fruits, so that Amazons foraged more often on trees bearing larger fruit crop size, while seldom visited less productive trees. Moreover, the relationship between fruit crop sizes and the number of depredated fruits was significant. However, when only damaged trees were assessed, I found a negative and significant relation between fruit crop size and proportional crop loss to Blue-Fronted Amazons. Taking into account this as a measure more directly related to the probability of seed survival, a negative density dependent effect emerged. Also, Amazons similarly damaged the fruit crops of either close or distant neighboring damaged trees. Hence, in spite of Blue-Fronted Amazons searched for E. gracilipes bearing large fruit crops, they were swamped due to the presence of more fruits than they could eat. Moderate seed predation by Blue-Fronted Amazons either at trees with large fruit crops or in areas where fruiting trees were aggregated implies in an enhanced probability of E. gracilipes seed survival and consequent regeneration success.

Hierarchical levels of seed predation variation by introduced beetles on an endemic Mediterranean palm.

Seed predators can limit plant recruitment and thus profoundly impinge the dynamics of plant populations, especially when diverse seed predators (e.g., native and introduced) attack particular plant populations. Surprisingly, however, we know little concerning the potential hierarchy of spatial scales (e.g., region, population, patch) and coupled ecological correlates governing variation in the overall impact that native and introduced seed predators have on plant populations. We investigated several spatial scales and ecological correlates of pre-dispersal seed predation by invasive borer beetles in Chamaerops humilis (Arecaceae), a charismatic endemic palm of the Mediteranean basin. To this end, we considered 13 palm populations (115 palms) within four geographical regions of the Iberian Peninsula. The observed interregional differences in percentages of seed predation by invasive beetles were not significant likely because of considerable variation among populations within regions. Among population variation in seed predation was largely related to level of human impact. In general, levels of seed predation were several folds higher in human-altered populations than in natural populations. Within populations, seed predation declined significantly with the increase in amount of persisting fruit pulp, which acted as a barrier against seed predators. Our results revealed that a native species (a palm) is affected by the introduction of related species because of the concurrent introduction of seed predators that feed on both the introduced and native palms. We also show how the impact of invasive seed predators on plants can vary across a hierarchy of levels ranging from variation among individuals within local populations to large scale regional divergences.

Ecological and evolutionary consequences of plant genotype diversity in a tri‐trophic system

The mechanisms by which plant diversity influences consumers are largely unexplored. Plant diversity reduces among‐plant competition, and as a result, may have cascading bottom‐up effects through altered resource quantity and quality. Less understood are parallel effects of resource heterogeneity on consumer foraging behaviors, and the consequences of such effects for trophic interactions and feedbacks on plant performance. Here, we asked whether genotypic diversity in the herb Ruellia nudiflora influences seed predator (SP) and parasitoid functional responses, and if such effects in turn influence selection on the plant. We established plots with plants of one or five genetic families (pool = 14) and measured fruit, seed predator, and parasitoid abundance. By eliminating direct plant–plant interactions, this experiment explicitly tested for plant diversity effects occurring through altered consumer behaviors (vs. effects through changes in plant quantity or quality). We compared observed plant fitness (under three trophic levels) to projected fitness in the absence of parasitoids (two trophic levels) and in the absence of seed predation (one trophic level) by computing the number of seeds consumed by the SP and the number of seeds rescued from consumption by parasitoids. We then compared the strength and mode of selection on fruit number between levels of diversity, separately under each trophic scenario. Plant diversity did not influence fruit, seed predator, or parasitoid abundance, but did alter plant–SP interactions. SP recruitment resembled a Type II functional response but saturated weakly in polycultures, with fewer SPs at intermediate fruit abundance and more SPs at high fruit abundance relative to monoculture. Parasitoid recruitment was weakly positively density dependent and unaffected by diversity. Importantly, we found that under the bi‐trophic scenario, the effect of diversity on SP recruitment altered the mode of selection on fruit number, from directional selection at low diversity to nonlinear (stabilizing) selection at high diversity. In contrast, diversity did not alter selection under mono‐ or tri‐trophic scenarios. Therefore, diversity effects on SP functional responses fed back to alter selection on fruit number, but parasitoids eliminated this linkage by weakening herbivore selection. Collectively, these findings provide novel evidence for the mechanistic basis of eco‐evolutionary feedbacks between plant diversity and consumers.

Polymorphic color vision in captive Uta Hick's cuxiús, or bearded sakis (Chiropotes utahickae).

The pitheciines (Chiropotes, Pithecia, and Cacajao) are frugivorous Neotropical primates that specialize on the predation of seeds from unripe fruits, usually cryptic against the foliage. However, little is known about the color vision distribution within this taxon, and even less about the abilities shared by these animals regarding discrimination of chromatic targets. The aim of this study was to evaluate the color vision perception of captive Uta Hick's cuxiús, or bearded sakis (Chiropotes utahickae) through a behavioral paradigm of color visual discrimination, as well as to estimate, by genetic studies, the number and kinds of medium to long wavelength cone photopigment (opsins) encoded by this species. Among 12 cuxiús (7 males and 5 females) studied only 1 female was diagnosed as a trichromat. Results from genotyping were in line with our behavioral data and showed that cuxiús carried one (dichromat) or two (trichromat) medium to long wavelength pigments alleles, demonstrating a color vision polymorphism in C. utahickae similar to the majority of Neotropical Primates.

Granivory of invasive, naturalized, and native plants in communities differentially susceptible to invasion.

Seed predation is an important biotic filter that can influence abundance and spatial distributions of native species through differential effects on recruitment. This filter may also influence the relative abundance of nonnative plants within habitats and the communities' susceptibility to invasion via differences in granivore identity, abundance, and food preference. We evaluated the effect of postdispersal seed predators on the establishment of invasive, naturalized, and native species within and between adjacent forest and steppe communities of eastern Washington, USA that differ in severity of plant invasion. Seed removal from trays placed within guild-specific exclosures revealed that small mammals were the dominant seed predators in both forest and steppe. Seeds of invasive species (Bromus tectorum, Cirsium arvense) were removed significantly less than the seeds of native (Pseudoroegneria spicata, Balsamorhiza sagittata) and naturalized (Secale cereale, Centaurea cyanus) species. Seed predation limited seedling emergence and establishment in both communities in the absence of competition in a pattern reflecting natural plant abundance: S. cereale was most suppressed, B. tectorum was least suppressed, and P. spicata was suppressed at an intermediate level. Furthermore, seed predation reduced the residual seed bank for all species. Seed mass correlated with seed removal rates in the forest and their subsequent effects on plant recruitment; larger seeds were removed at higher rates than smaller seeds. Our vegetation surveys indicate higher densities and canopy cover of nonnative species occur in the steppe compared with the forest understory, suggesting the steppe may be more susceptible to invasion. Seed predation alone, however, did not result in significant differences in establishment for any species between these communities, presumably due to similar total small-mammal abundance between communities. Consequently, preferential seed predation by small mammals predicts plant establishment for our test species within these communities but not between them. Accumulating evidence suggests that seed predation can be an important biotic filter affecting plant establishment via differences in consumer preferences and abundance with important ramifications for plant invasions and in situ community assembly.

Soil fertility and parasitoids shape herbivore selection on plants

Summary Although plants and herbivores interact under varying soil resources and natural enemy effects, little is known about how these factors influence plant–herbivore interactions and shape the evolution of plant and herbivore traits. Here, we ask whether soil fertility and parasitoids shape selection on fruit number imposed by a seed predator (SP) on the perennial herb Ruellia nudiflora. We used a common garden where half the plants of 14 genetic families were fertilized and recorded the abundance of cleistogamous (CL) fruits and seeds, SPs and parasitoids. We calculated relative fitness per family based on CL seed number under the following three scenarios: three trophic levels (accounting for SP and parasitoid effects), two trophic levels (accounting for SP but not parasitoid effects), and one trophic level (fitness in absence of SPs), and compared selection strength on fruit number between trophic scenarios and fertility environments. In unfertilized conditions, SPs selected for increased CL fruit number, whereas parasitoids dampened (but did not eliminate) this selective impact. With fertilization, however, selection by SPs was reduced and unaffected by parasitoids. Synthesis. Overall, we show that parasitoids can shape herbivore selection on plants, but that both herbivore and parasitoid selective impacts depend upon the abiotic environment. These findings underscore how linkages between abiotic factors and trophic complexity influence the ecological and evolutionary outcomes of species interactions.

Direct seeding of dry forest tree species in abandoned pastures: effects of grass canopy and seed burial on germination

AbstractNatural tree regeneration in abandoned pastures can be hampered by various biotic and abiotic filters, including seed removal and predation. We tested the effects of maintenance and removal of grass and seed deposition (buried and unburied) on seed germination of 12 tree species in dry forest pastures. We obtained evidence supporting the hypothesis that seeds attain higher germination under a grass canopy than on bare ground. For most species, grass cover provides safety from seed predators and facilitates germination by providing a suitable microclimate with soil humidity similar to the forest. The hypothesis that buried seeds attain higher germination was not supported by our data. Predation and removal of unburied seeds ranged from 0 to 77 % and, alone or together, were the major causes of non‐germination. Direct seeding is a promising technique for revegetation of recently abandoned pastures in areas originally covered by tropical dry forests. The high germination rate of seeds deposited on the ground and under grass reduces costs during initial restoration stages, potentially facilitating the spread and use of this technique.