Fate Of Seeds Research Articles

Tracking individual seed fate confirms mainly antagonistic interactions between rodents and European beech.

Food-hoarding granivores act as both predators and dispersers of plant seeds, resulting in facultative species interactions along a mutualism-antagonism continuum. The position along this continuum is determined by the positive and negative interactions that vary with the ratio between seed availability and animal abundance, particularly for mast-seeding species with interannual variation and spatial synchrony of seed production. Empirical data on the entire fate of seeds up to germination and the influence of rodents on seed survival is rare, resulting in a lack of consensus on their position along the mutualism-antagonism continuum. Here, we quantified annual seed rain and rodent abundance in an old-growth European beech forest and tracked 639 beechnuts to the seedling stage with 84% of seeds successfully located. Over 4 study years that covered the range of seed-to-rodent ratios, not a single seed successfully germinated after dispersal, illustrating a predominantly antagonistic interaction between rodents and seeds of European beech. Therefore, our findings do not support the predator dispersal hypothesis and partially contradict the predator satiation hypothesis, as the highest number of germinants and intact seeds were found in situ after an intermediate seed crop, not a bumper crop. Our results underline the necessity to track seeds up to germination.

Vertebrate seed predation can limit recruitment of later‐successional species in tropical forest restoration

AbstractThe effects of vertebrate seed predation on the regeneration of restored forests are not well understood because most past studies have focused on seed predation within the first few years after restoration and have measured seed removal without quantifying subsequent seedling establishment of seeds that avoid predation. Quantifying the establishment of seeds that escape predation in restored forests at later stages of regrowth is crucial for anticipating longer‐term recovery trajectories. Here, we evaluated the potential role of vertebrate seed predators in limiting recruitment of later‐successional tree species in nine forests actively restored ≥15 years prior and in four paired remnant forest fragments embedded in an agricultural landscape in southern Costa Rica. We conducted seed addition experiments with four tree species inside and outside vertebrate exclosures and used camera trapping to detect seed predators. To determine the fate of seeds that avoided predation, we also measured seedling establishment after 1 year, given that other mortality factors may compensate in the absence of vertebrate seed predation. We detected two species of birds and five species of granivorous mammals removing seeds. Seed tagging indicated that most removal resulted in predation. For three of the four tree species tested, vertebrate seed predation reduced seedling establishment. The magnitude of this effect depended on species' susceptibility to other causes of mortality during the seed‐to‐seedling transition. Our study demonstrates that vertebrate seed predators can substantially reduce later‐successional seedling recruitment in restored forests and should be considered alongside dispersal limitation and microsite conditions as factors slowing forest recovery.Abstract in Spanish is available with online material.

Lagrangian flow networks for passive dispersal: Tracers versus finite-size particles.

The transport and distribution of organisms such as larvae, seeds, or litter in the ocean as well as particles in industrial flows is often approximated by a transport of tracer particles. We present a theoretical investigation to check the accuracy of this approximation by studying the transport of inertial particles between different islands embedded in an open hydrodynamic flow aiming at the construction of a Lagrangian flow network reflecting the connectivity between the islands. To this end, we formulate a two-dimensional kinematic flow field which allows the placement of an arbitrary number of islands at arbitrary locations in a flow of prescribed direction. To account for the mixing in the flow, we include a von Kármán vortex street in the wake of each island. We demonstrate that the transport probabilities of inertial particles making up the links of the Lagrangian flow network essentially depend on the properties of the particles, i.e., their Stokes number, the properties of the flow, and the geometry of the setup of the islands. We find a strong segregation between aerosols and bubbles. Upon comparing the mobility of inertial particles to that of tracers or neutrally buoyant particles, it becomes apparent that the tracer approximation may not always accurately predict the probability of movement. This can lead to inconsistent forecasts regarding the fate of marine organisms, seeds, litter, or particles in industrial flows.

Seed dormancy types and germination response of 15 plant species in temperate montane peatlands.

Despite their crucial role in determining the fate of seeds, the type and breaking mode of seed dormancy in peatland plants in temperate Asia with a continental monsoon climate are rarely known. Fifteen common peatland plant species were used to test their seed germination response to various dormancy-breaking treatments, including dry storage (D), gibberellin acid soaking (GA), cold stratification (CS), warm followed cold stratification (WCS), GA soaking + cold stratification (GA + CS) and GA soaking + warm followed cold stratification (GA + WCS). Germination experiment, viability and imbibition test, and morphological observation of embryos were conducted. Of the 15 species, nine showed physiological dormancy (PD), with non-deep PD being the dominant type. Four species, Angelica pubescens, Cicuta virosa, Iris laevigata, and Iris setosa exhibited morphophysiological dormancy. Two species, Lycopus uniflorus and Spiraea salicifolia, demonstrated nondormancy. Overall, the effect hierarchy of dormancy-breaking is: CS > GA > WCS > GA + CS > D > GA + WCS. Principal component analysis demonstrated that seed traits, including embryo length: seed length ratio, seed size, and monocot/eudicot divergence, are more likely to influence seed dormancy than environmental factors. Our study suggests that nearly 90% of the tested peatland plant species in the Changbai Mountains demonstrated seed dormancy, and seed traits (e.g. embryo-to-seed ratio and seed size) and abiotic environmental factors (e.g. pH and temperature seasonality) are related to germination behavior, suggesting seed dormancy being a common adaptation strategy for the peatland plants in the temperate montane environment.

Effects of Seed Size and Cache Density on the Seed Fate of Quercus wutaishanica Mediated by Rodents.

Animal-mediated seed dispersal is very important for plant population regeneration and the stability of forest ecosystems. Seed size and cache density are important factors for seed dispersal, but we still know little about seed size selection at different cache densities. Here, we conducted field experiments in a Larix principis-rupprechtii plantation in the Liupan Mountains in Ningxia province to investigate the effects of tag-marked Quercus wutaishanica seeds of different sizes and cache densities on predation and the scatter-hoarding behavior of rodents. The results showed lower proportions of intact in situ (IIS) and eaten in situ (EIS) large seeds than small seeds at all levels of cache density, with the exception of IIS seeds at a 6.25 seed·m-2 cache density. A higher proportion of small seeds were eaten after removal (EAR), but a higher proportion of large seeds were scatter-hoarded (SH) by rodents at most cache densities. Furthermore, rodents preferentially removed large seeds farther away for eating or scatter-hoarding. The IIS and EIS proportions of both large and small seeds declined, but the proportion of the two types of seeds that were EAR fluctuated, increasing with increasing cache density. Rodents preferred to increase the proportion of scatter-hoarding of large seeds with increasing cache density, whereas the proportion of scatter-hoarding of small seeds was maximized at a cache density of 6.25 seed·m-2. Both the eaten distance after removal (EDAR) and scatter-hoarded distance (SHD) increased with increasing cache density. These results suggest that large seeds are more likely to be scatter-hoarded and removed to longer distances than small ones. Rodents tended to reduce the seed proportion of EIS seeds and increased the proportion of seeds EAR and SH, and accordingly increased EDAR and SHD with increasing cache density. This study provides some scientific basis for animal-mediated seed dispersal.

Potential Gene Flow Between <i>Gossypium hirsitum</i> and <i>Abelmoschus esculentus</i> Through Interspecific Hybridization

The introduction of transgenic varieties of cotton (<i>Gossypium hirsitum</i>) in Cameroon has posed numerous concerns. One of the most concern was the horizontal transfer of the <i>Bt</i> gene to related species such as <i>Abelmoschus esculentus</i>. The current study was conducted to assess the occurrence <i>Bt</i> gene transfer from <i>Gossypium hirsitum </i>to<i> Abelmoschus esculentus</i>. To achieve this, the stigma receptivity periods and the viability of pollen grains were evaluated. The fruit set rates of 675 controlled intra- and interspecific crosses were assessed. The results showed that stigma receptivity and pollen grain viability are optimal at anthesis in both species, with a longer duration over 24 hours in <i>G. hirsitum</i>. Intra-specific crosses within the two species have shown fruit set rates of nearly 60-80%. Interspecific crosses gave a fruit set rate close to 2%, especially when <i>A. esculentus</i> is used as the female parent, and zero results in reciprocal crosses. The finding of the study pointed out that the possibility of horizontal transfer of a transgene to cotton relatives. In future studies, it would be useful to monitor the fate of seeds from interspecific crosses between both species and assess the agro-morphological and molecular characteristics of these possible hybrids.

Effects of habitat differences on the scatter-hoarding behaviour of rodents (Mammalia, Rodentia) in temperate forests.

To discover the differences in hoarding strategies of rodents for different seeds in different habitats, we labelled and released three different types of seeds, including Pinuskoraiensis, Corylusmandshurica, and Quercusmongolica, in temperate forests of northeastern China and investigated the fate of seeds in four different habitats that included a broad-leaved forest, mixed-forest edge, mixed forest, and artificial larch forest. Our research showed that the hoarding strategy of rodents was found to vary substantially in different habitats. The survival curves of seeds from different habitats showed the same trend, but the rates of consumption in different habitats varied. More than 50% of the seeds in the four habitats were consumed by the tenth day. It took 20 days to consume more than 70% of the seeds. The rate of consumption of P.koraiensis seeds reached 96.70%; 99.09% of the C.mandshurica seeds were consumed, and 93.07% of the Q.mongolica seeds were consumed. The seeds were consumed most quickly in the artificial larch forest. In general, most of the early seeds were quickly devoured. After day 20, the consumption gradually decreased. Rodents found the seeds in the artificial larch forest in a shorter average time than those in the other types of forests. The average earliest discovery time was 1.4 ± 0.9 d (1-3 d). The average earliest discovery time in all the other three habitats exceeded 7 d. The median removal times (MRT) was distributed around the seeds at 14.24 ± 10.53 d (1-60 d). There were significant differences in the MRT among different habitats. It was shortest in the artificial larch forest at 7.67 ± 6.80 d (1-28 d). In contrast, the MRT in the broad-leaved forest was the longest at 17.52 ± 12.91 d (4-60 d). There were significant differences in the MRT between the artificial larch forest and the other habitats. There was less predation of the three types of seeds at the mixed-forest edge, and the most seeds were dispersed. The rates of predation of the P.koraiensis, C.mandshurica, and Q.mongolica seeds were 28.33%, 15.83%, and 44.0%, and 59.17%, 84.17%, and 48.0% of the seeds were dispersed, respectively. The average dispersal distances of all the seeds were less than 6 m, and the longest distance recorded was 18.66 m. The dispersal distances and burial depths differed significantly among the four types of habitats. The distance of seed dispersal was primarily distributed in 1-6 m.

Structure of axion miniclusters

The Peak-Patch algorithm is used to identify the densest minicluster seeds in the initial axion density field simulated from string decay. The fate of these dense seeds is found by tracking the subsequent gravitational collapse in cosmological $N$-body simulations. We find that miniclusters at late times are well described by NFW profiles, although for around 80\% of simulated miniclusters a single power-law density profile of $r^{-2.9}$ is an equally good fit due to the unresolved scale radius. Under the assumption that all miniclusters with an unresolved scale radius are described by a power-law plus axion star density profile, we identify a significant number of miniclusters that might be dense enough to give rise to gravitational microlensing if the axion mass is $0.2 \,\mathrm{meV}\lesssim m_a \lesssim 3\,\mathrm{meV}$. Higher resolution simulations resolving the inner structure and axion star formation are necessary to explore this possibility further.

Understanding of histological and physiological alterations in hull-less seeded pumpkin

Pumpkin seeds have great therapeutic value but remain underutilized due to its hulled character. However, a hull-less mutation revolutionized the fate of pumpkin seeds in the oil industry by omitting the decortication process. Therefore, the present research was conducted to understand the histological and physiological changes caused by this mutation in the developing seeds of pumpkin that produces the desired hull-less phenotype. In scanning electronic microscopy, a distinct five cell layered structure was observed in the seed coat of hulled (PCK-1) genotype, which was collapsed in the partially hulled (WT-2046) and the hull-less (PMK-1) genotypes. Also the seed coat layers increased continuously in hulled genotype until maturity; however, these declined after 20 DPA in the other two genotypes. Physiological studies revealed that protein, amino acid, starch and lipid content followed the same trend, but the wall components (pectin, hemicelulose, cellulose and lignin) differed significantly amongst the genotypes. The wall components increased continuously until maturity in the hulled genotype, but decreased after 20 DPA in the partially hulled and hull-less genotypes. Further, the correlation, PCA and cluster analysis also reinforced that the wall components especially the lignin was responsible in maintaining the seed coat structure in the hulled genotype and its reduction poses as a reason for the collapsed seed coat in other two genotypes. Lignin reduction was noticed at 20 DPA in the hull-less genotype and therefore, this stage can be used to identify the gene responsible for lignin synthesis in the seed coats.

The dual fates of exogenous tau seeds: Lysosomal clearance versus cytoplasmic amplification

Tau assembly movement from the extracellular to intracellular space may underlie transcellular propagation of neurodegenerative tauopathies. This begins with tau binding to cell surface heparan sulfate proteoglycans, which triggers macropinocytosis. Pathological tau assemblies are proposed then to exit the vesicular compartment as “seeds” for replication in the cytoplasm. Tau uptake is highly efficient, but only ∼1 to 10% of cells that endocytose aggregates exhibit seeding. Consequently, we studied fluorescently tagged full-length (FL) tau fibrils added to native U2OS cells or “biosensor” cells expressing FL tau or repeat domain. FL tau fibrils bound tubulin. Seeds triggered its aggregation in multiple locations simultaneously in the cytoplasm, generally independent of visible exogenous aggregates. Most exogenous tau trafficked to the lysosome, but fluorescence imaging revealed a small percentage that steadily accumulated in the cytosol. Intracellular expression of Gal3-mRuby, which binds intravesicular galactosides and forms puncta upon vesicle rupture, revealed no evidence of vesicle damage following tau exposure, and most seeded cells had no evidence of endolysosome rupture. However, live-cell imaging indicated that cells with pre-existing Gal3-positive puncta were seeded at a slightly higher rate than the general population, suggesting a potential predisposing role for vesicle instability. Clearance of tau seeds occurred rapidly in both vesicular and cytosolic fractions. The lysosome/autophagy inhibitor bafilomycin inhibited vesicular clearance, whereas the proteasome inhibitor MG132 inhibited cytosolic clearance. Tau seeds that enter the cell thus have at least two fates: lysosomal clearance that degrades most tau, and entry into the cytosol, where seeds amplify, and are cleared by the proteasome.

Roads Disrupt Frugivory and Seed Removal in Tropical Animal-Dispersed Plants in French Guiana

Ecological interactions are being affected at unprecedented rates by human activities in tropical forests. Yet, the continuity of ecological functions provided by animals, such as seed dispersal, is crucial for forest regeneration and species resilience to anthropogenic pressures. The construction of new roads in tropical forests is one of the main boosters of habitat destruction as it facilitates human access to previously isolated areas and increases defaunation and loss of ecological functions. It, therefore, becomes increasingly urgent to rapidly assess how recently opened roads and associated anthropogenic activities affect ecological processes in natural habitats, so that appropriate management measures to conserve diversity can be taken. In this study, we aimed to evaluate the effects of anthropogenic pressures on the health status of a mature rainforest crossed by a newly opened road in French Guiana. For this, we combined different methods to conduct a rapid assessment of the forest’s health status. Firstly, we evaluated the activity of frugivores using camera traps deployed in four forest patches located near (&amp;lt;1 km) ecological corridors preserved as canopy bridges over the road during the fruiting periods of four animal-dispersed tree species. Secondly, we analyzed the fate of seeds enclosed in animal-dispersed tropical fruits by calculating the proportions of fruits consumed and seeds removed (either dispersed or predated) by frugivores. Results show that the proportion of fruits opened and consumed was lower in the forest areas located near the road than in the control forest, and this difference was more significant for plant species strictly dependent on large-bodied primates for seed dispersal than for species relying on both primates and birds. Camera traps showed the presence of small primates and kinkajous feeding on Virola fruits in the forest impacted by the road, where large primates were absent. It is thus likely that smaller frugivores exert a compensatory effect that maintains ecological functions near the road. Despite efforts made to preserve forest continuity through ecological corridors, anthropogenic pressures associated with road proximity are affecting wildlife and disrupting associated ecological functions crucial for plant regeneration, contributing to further forest degradation.

Primate reintroduction promotes the recruitment of large-seeded plants via secondary dispersal

The loss of larger frugivores alters seed dispersal. Species reintroductions have been proposed as a strategy for reversing local disperser extinctions. However, their effects on ecological processes have seldom been assessed. Howler monkeys (Alouatta guariba) have been reintroduced in Tijuca National Park, a defaunated Atlantic Forest fragment. We compared the fate of seeds dispersed by howlers to dispersal by two other frugivores present in the park: capuchin monkeys (Sapajus nigritus) and guans (Penelope superciliaris). Howlers produce clumped defecations that attract dung beetles, which provide secondary dispersal by burying seeds embedded in feces. We expected that seeds dispersed by howlers would have a different fate from those dispersed by capuchins and guans, since their scattered defecations are less attractive to dung beetles. We followed the fate of seeds 3–14 mm in diameter through three processes after seed deposition: secondary dispersal, predation, and seedling emergence. We estimated the probabilities in each step according to the primary disperser and plant species. Dispersal by howlers increased the recruitment of large-seeded plants because of the higher probability of secondary dispersal of the seeds in their feces. Fewer of the seeds dispersed by capuchins or guans were buried, regardless of size, and burial depths were shallower. For 3 mm seeds, the final recruitment probability was similar across frugivores. However, more of the larger seeds reached the seedling stage when dispersed by howlers since they were buried more deeply, which increased their survival without affecting seedling emergence. Reintroductions can thus contribute to restoring ecological processes.

Understanding and Managing Weed Seed Banks: A Review

The seed bank is an important part of the weed life cycle since it is where weed seeds rest. Seed banks are the only source of future weed populations for those annual and perennial weed species that reproduce only through seeds. As a result, understanding the fate of seeds in the seed bank may be crucial for overall weed management. When weed seeds reach the seed bank, a number of factors determine how long they may stay viable. Seeds in the seed bank can sense their surroundings and use these stimuli to go dormant or commence germination. Soil and crop management strategies can have a direct impact on the environment of seeds in the soil weed seed bank, allowing them to be utilised to manage weed seed longevity and germination.

In vitro digestion of whole chia seeds (Salvia hispanica L.): Nutrient bioaccessibility, structural and functional changes

AbstractDietary chia seed (Salvia hispanica L.) has significant health‐related benefits due to its high nutrient contents. However, few studies reported the fate of whole seeds in the gastrointestinal tract. Herein, we explored the digestive characteristics in terms of hydrolysis of nutrients, structural and functional properties with a static in vitro digestion method. After gastrointestinal digestion, the digestibility of lipid and protein was 0.46% and 11.38%, respectively. The release rates of tryptophan, tyrosine and lysine were greater than 20%, whereas the glutamic acid and aspartic acid were less than 5%. The microscopic results (optical microscopy (OM), laser scanning confocal microscopy (LSCM) and scanning electron microscopy (SEM)) demonstrated that the seeds remained intact, and the mucilage adhered tightly to the seed coat during digestion. The water holding capacity and oil holding capacity of seeds accounted for 6.37 and 3.28 g/g after intestinal digestion, which were significantly lower than gastric digestion endpoints (P &lt; 0.05). And there were no significant differences in Fourier transform infrared spectroscopy of G‐Mucilage and I‐Mucilage. In general, preprocessing before being consumed is necessary for chia seeds to take full advantage of rich polyunsaturated fatty acids and proteins.

Differential Interactions of Molecular Chaperones and Yeast Prions.

Baker’s yeast Saccharomyces cerevisiae is an important model organism that is applied to study various aspects of eukaryotic cell biology. Prions in yeast are self-perpetuating heritable protein aggregates that can be leveraged to study the interaction between the protein quality control (PQC) machinery and misfolded proteins. More than ten prions have been identified in yeast, of which the most studied ones include [PSI+], [URE3], and [PIN+]. While all of the major molecular chaperones have been implicated in propagation of yeast prions, many of these chaperones differentially impact propagation of different prions and/or prion variants. In this review, we summarize the current understanding of the life cycle of yeast prions and systematically review the effects of different chaperone proteins on their propagation. Our analysis clearly shows that Hsp40 proteins play a central role in prion propagation by determining the fate of prion seeds and other amyloids. Moreover, direct prion-chaperone interaction seems to be critically important for proper recruitment of all PQC components to the aggregate. Recent results also suggest that the cell asymmetry apparatus, cytoskeleton, and cell signaling all contribute to the complex network of prion interaction with the yeast cell.

Direct seeding as a recruitment alternative for the threatened tropical palm Syagrus coronata (Mart.) Beccari in Brazilian dry forest.

Habitat loss reduces biodiversity and threatens ecological services. The use of techniques for vegetation restoration such as direct seeding seems promising, mainly because it reduces costs and labor. The aim of this study was to investigate which are the main ecological filters that can inhibit the success of direct seeding, using Syagrus coronata (Mart.) Beccari (Arecaceae), a species that has great ecological and extractive importance for the Brazilian semi-arid region, and is found in habitats with different management intensities. The following hypotheses were tested: (1) managed habitat (pasture) and natural habitat (caatinga vegetation) show differences in seed fate; and (2) defleshed fruits will have greater seed germination success compared to not defleshed. Seed fate was evaluated for two consecutive years, year I (2016-2017) and year II (2017-2018). Within these years, 800 mature fruits were buried along 300 m transects, half with defleshing treatment, and monitored during 240 days. The highest seed survival occurred in year II, this result may be associated with higher rainfall recorded during the experiment, considering that there was no difference in seed germination between habitats. Defleshing facilitated germination and reduced insect predation, likely by removing invertebrate larvae before they have reached the seed. Desiccation was the major cause of mortality in the entire study and was higher in the managed habitat. Water insufficiency may have caused the deactivation of antioxidant mechanisms and affected the embryo. Although defleshing may favor germination, this procedure would not be indicated for pastures as it favors desiccation. The study showed how habitat management and fruit defleshing can affect seed fate. More studies on ecological relationships need to be carried out to increase understanding of how habitat modification affects the functioning of arid ecosystems.

Dual ecological functions of scatter-hoarding rodents: pollinators and seed dispersers of Mucuna sempervirens (Fabaceae).

Double mutualism, that is, pollination and seed dispersal of the same plant species mediated by the same animal partners, is important but remains elusive in nature. Recently, rodent species were found as key pollinators (i.e. explosive openers) for some Mucuna species in (sub)tropical Asia, but no evidence has shown whether and how these rodents could also act as legitimate seed dispersers via scatter-hoarding for those producing large seeds. Here, my aim was to test the hypothesis that scatter-hoarding rodents could act as double mutualists for both pollination and seed dispersal of the same Mucuna species, that is, Mucuna sempervirens (Fabaceae). Based on camera-trapping survey at 2 locations with or without squirrel presence in the Dujiangyan subtropical forests, Southwest China, 7 mammals and birds were identified as explosive openers for M. sempervirens flowers, but Leopoldamys edwardsi (rats) and Paguma larvata (civets) were the main pollinators at the squirrel-absent site, while Callosciurus erythraeus (squirrels) were the main pollinators at the squirrel-present site. By tracking the fate of individually-tagged seeds over 5 years at each site, I provide the first evidence for seed-eating rodents as legitimate seed dispersers via scatter-hoarding of seeds in this world-wide plant genus, although dispersal services were slightly reduced at squirrel-absent site. More importantly, the dual roles of scatter-hoarding rodents as key pollinators and seed dispersers for the same Mucuna species have shown a clear relationship of double mutualism, and their key services may be essential for population conservation of these Mucuna species in human-disturbed landscapes.

Seed fate, seedling establishment and the role of propagule size in forest regeneration under climate change conditions

Climate change can affect tree recruitment altering post-dispersal seed fates and impairing seedling development, and these effects will be stronger at man-disturbed areas than beneath forest canopies. Seed biomass, however, positively influences tree recruitment processes and its relevance increases with environmental harshness. Therefore, this seed trait may become critical for forest regeneration under climate change scenarios. We experimentally tested these hypotheses with two Mexican oaks that dominate forests at sites where temperature will increase and rainfall will decrease in the next 20 years. At both experimental sites, we sowed acorns of varying biomass at forest understories and deforested areas under the current climate and simulated climate change conditions. We measured microclimate, incidence of seed parasitism by insects and fungi, germination, shoot emergence, and seedling survival and growth over a year. Temperature in climate change simulations was increased 2 °C and rainfall was reduced 17–18%, and this concurred with the near-term changes expected for both variables at the experimental sites. Climate change conditions intensified insect parasitism and decreased fungal infestation on seeds, but these effects were only found within forests and they did not relate with propagule size. Increased warming and drought reduced germination, shoot emergence, and seedling survival and growth at forests and deforested areas, but all these processes were positively related with seed biomass. Indeed, in an oak species, these relationships displaced towards bigger-sized seeds under climate change conditions. Our findings suggest that climate change can alter the intensity of seed-parasite interactions and impair tree establishment processes, also suggesting that this phenomenon will favor large-sized over small-sized seeds during recruitment of some tree species.

Effects of season and food on the scatter-hoarding behavior of rodents in temperate forests of Northeast China

To explore the differences in hoarding strategies of rodents for different seeds in various seasons, we labeled and released the seeds of Pinus koraiensis, Corylus mandshurica, Quercus mongolica and Prunus sibirica in temperate forests of Northeast China and investigated the fate of the seeds in spring and autumn. The analysis showed that the hoarding strategies of the rodents varied substantially between seasons. The seeds were consumed faster in the spring than in the autumn. More than 50% of the seeds in the two seasons were consumed by the 16th day. It took 36 days to consume 75% of the seeds in the spring and 44 days in the autumn. The rate of consumption of the seeds in the spring was greater than in the autumn, and the rate of spread of the seeds was greater in the autumn. The distances of removal for the consumption and dispersal of seeds in the spring (3.26 ± 3.21 m and 4.15 ± 3.52 m, respectively) were both shorter than those in the autumn (3.74 ± 3.41 m and 4.87 ± 3.94 m, respectively). In addition, the fate of different seeds varied significantly owing to differences in hoarding strategies. The seeds of the three preferred species, P. koraiensis, C. mandshurica, and Q. mongolica, were quickly consumed. More than 90% of the seeds of these species were consumed. Only 21% of Pr. sibirica seeds were slowly consumed, and the two seasons had the same seed consumption rate patterns: the consumption rate of P. koraiensis seeds was the highest, followed by C. mandshurica, then Q. mongolica, and finally Pr. sibirica. The median removal times of the two seasons were different, but the rules were the same: P. koraiensis was the shortest, followed by C. mandshurica, and the third was Q. mongolica. In both seasons, the most predated in situ seeds were those of P. koraiensis; the most hoarded seeds were those of C. mandshurica, and the most unconsumed seeds were those of Pr. sibirica.

Ant Guild Identity Determines Seed Fate at the Post-Removal Seed Dispersal Stages of a Desert Perennial.

Simple SummaryAnts play a dual role in their interaction with plant seeds. Many ant species, mainly harvester ants, consume plant seeds (granivory), whereas other ants, mainly scavengers, provide a beneficial seed dispersal service. Granivory by ants is frequently documented in deserts, but beneficial seed dispersal is rarely studied in such ecosystems. We followed the handling of seeds of Sternbergia clusiana, an ant-dispersed plant, by two guilds of desert ants. We focused on the treatment of seeds within the nest and on the redispersal of seeds after ejection from the nest. Scavenging ants rarely consumed the seed itself, they deposited most seeds away from the nest in apparently suitable microhabitats. In addition, we found that most of the seeds that were relocated by scavenging ants arrived at sites under the canopy of shrubs. Such sites might be beneficial for the establishment and success of plants in the arid environment. Indeed, we found that the subject plant was more likely to be found under shrubs than elsewhere, which suggests that it benefits from being placed there. Such documentation of seed dispersal activity by scavenging ants in arid ecosystems suggests they may be efficient seed dispersers in deserts, as they are in other ecosystems.Ants play a dual role in their interaction with plant seeds. In deserts, the consumption of seeds by granivorous ants is common, whereas mutualistic seed dispersal, often associated with scavenging ants, is rarely documented. We evaluated the contribution of both ant guilds to efficient seed dispersal of an ant-dispersed plant, Sternbergia clusiana, in a desert ecosystem. We presented seed to colonies of three species of desert ants from the Cataglyphis (scavengers) and Messor (granivorous) genera. We recorded seed consumption, ejection from the nest, and seed transportation to potentially beneficial microhabitats. We evaluated microhabitat quality by testing the association between habitat types and the plant at various life stages. As expected, granivores mainly consumed the seeds, whereas scavengers consumed the elaiosome (seed appendage serving as a reward), but left the seeds intact. Moreover, scavenging ants relocated the seeds much further than granivores, mainly to shrub patches. The disproportional distribution of the plant under shrubs at several life stages suggests that this microhabitat is beneficial for the plant. Overall, while granivores seem to mainly harm seed dispersal, we provide the first evidence for the beneficial contribution of scavenging ants in deserts, showing they exhibit the same suite of characteristics that render them efficient seed dispersers in other ecosystems.