As ecosystem degradation becomes more widespread, there is a growing need for efficient and effective forest restoration methods. Direct seeding is one such method that can be used to cover a relatively large area, pa...As ecosystem degradation becomes more widespread, there is a growing need for efficient and effective forest restoration methods. Direct seeding is one such method that can be used to cover a relatively large area, particularly places with difficult-to-access terrain. One major obstacle hampering successful restoration via direct seeding is seed predation, as seeds are damaged or eaten. We tested the effectiveness of encrusting six species of native seeds with biochar-based coating in reducing the seeds’ chances of being predated on degraded hillsides and landslide scars in Hong Kong. The six seeded species are native trees and shrubs, including both late-successional and pioneer species that are present in forests and shrublands. Our results show that biochar-based seed coats were able to significantly reduce overall seed predation by 5.77% (SE = 1.41, p < 0.05). Additionally, we found varied effectiveness of the biochar-based seed coats across species and seed morphology. Of the six species that were included, four of them had significantly reduced seed predation after encrusting with biochar-based seed coats, while two other species were not significantly affected by the biochar-based seed coats. When we investigated seed predation against seed morphology, we found that while the species with larger seeds were more likely to be predated when sown without any biochar-based seed coat, the effectiveness of the biochar-based seed coat to reduce predation also increased with larger seeds. Our results suggest that encrusting seeds with biochar-based seed coats is an effective means of reducing seed predation.展开更多
By tracking the fate of individual seeds from 6 frugivore-dispersed plants with contrasting seed traits in a fragmented subtropical forest in Southwest China,we explored how rodent seed predation and hoarding we...By tracking the fate of individual seeds from 6 frugivore-dispersed plants with contrasting seed traits in a fragmented subtropical forest in Southwest China,we explored how rodent seed predation and hoarding were influenced by seed traits such as seed size,seed coat hardness and seed profitability.Post-dispersal seed fates varied significantly among the 6 seed species and 3 patterns were witnessed:large-seeded species with a hard seed coat(i.e.Choerospoadias axillaries and Diospyros kaki var.silvestris)had more seeds removed,cached and then surviving at caches,and they also had fewer seeds predated but a higher proportion of seeds surviving at the source;medium-sized species with higher profitability and thinner seed coat(i.e.Phoebe zhennan and Padus braohypoda)were first harvested and had the lowest probability of seeds surviving either at the source or at caches due to higher predation before or after removal;and small-seeded species with lower profitability(i.e.Elaeocarpus japonicas and Cornus controversa)had the highest probability of seeds surviving at the source but the lowest probability of seeds surviving at caches due to lower predation at the source and lower hoarding at caches.Our study indicates that patterns of seed predation,dispersal and survival among frugivore-dispersed plants are highly determined by seed traits such as seed size,seed defense and seed profitability due to selective predation and hoarding by seed-eating rodents.Therefore,trait-mediated seed predation,dispersal and survival via seed-eating rodents can largely affect population and community dynamics of frugivore-dispersed plants in fragmented forests.展开更多
Wild bananas are abundant in tropical areas and many ecologists have observed that the succession process is quicker following increased disturbance.This study was conducted to analyze animal–seed interactions and th...Wild bananas are abundant in tropical areas and many ecologists have observed that the succession process is quicker following increased disturbance.This study was conducted to analyze animal–seed interactions and their effects on the seed fate of a wild banana species(Musa acuminata)in tropical southern Yunnan(China)through experiments considering spatial(site and habitat)and temporal(seasons)variation.The largest proportion of fruits(81%)was removed by frugivorous seed dispersers,especially by bats at nighttime.Only 13%of the fruits were removed by climbing seed predators(different species of rats).In the exclosure treatment,rodents accounted for a significantly higher total artificially exposed seed removal number than ants,but with spatial and temporal differences.The highest seed predation rate by rodents(70%)was found in forest with wild banana stands,corresponding with the highest rodent diversity(species numbers and abundance)among the habitat types.In contrast,the seed removal number by ants(57%)was highest in the open land habitats,but there was no close correlation with ant diversity.Seed removal numbers by ants were significantly higher in the dry compared to the rainy season,but rodent activity showed no differences between seasons.The overall results suggest that the largest proportion of seeds produced by wild banana are primarily dispersed by bats.Primary seed dispersal by bats at nighttime is essential for wild banana seeds to escape seed predation.展开更多
Species introduced to habitats outside their native range often escape control by their natural enemies.Besides competing with native species,an alien species might also affect the native herbivores by introducing a n...Species introduced to habitats outside their native range often escape control by their natural enemies.Besides competing with native species,an alien species might also affect the native herbivores by introducing a new source of different quality food.Here,we describe the case of northern red oak(Quercus rubra)invasion in Europe.We collected data on insect(moth Cydia spp.and weevil Curculio spp.)seed predation of northern red oak in its native(USA,North America)and invasive(Poland,Europe)range,as well as for sessile oaks(Quercus petrea)in Europe.We also evaluated the quality of acorns as hosts for weevil larvae by collecting infested acorns and measuring weevil developmental success,and quantifying acorn traits such as seed mass,tannins,lipids and protein concentration.We used DNA barcoding to identify insects to the species level.The predation by moths was similar and very low in both species and in both ranges.However,red oaks escape pre-dispersal seed predation by weevils in Europe.Weevil infestation rates of northern red oak acorns in their invasive range were 10 times lower than that of sessile oaks,and also 10 times lower than that of red oaks in North America.Furthermore,even when weevils oviposited into northern red oaks,the larvae failed to develop,suggesting that the exotic host created a trap for the insect.This phenomenon might gradually decrease the local abundance of the seed predator,and further aid the invasion.展开更多
Post-dispersal seed predation plays an important role in plant demography and biodiversity maintenance.However,the effects of seed density on seed predation from previous studies have been inconsistent.We dissected th...Post-dispersal seed predation plays an important role in plant demography and biodiversity maintenance.However,the effects of seed density on seed predation from previous studies have been inconsistent.We dissected the effects of density on the 2-step processes of seed predation using 101520 seeds from 62 plant species in an alpine pine forest for 3 consecutive years.In this study we explained the current controversy surrounding the effects of density on seed predation.Seed encounter frequency(at least 1 seed being predated from an experiment depot)showed positive density dependence,while seed exploitation(the proportion of seeds being predated of the encountered depots)showed negative density dependence.Both density effects showed a consistent trend but with different magnitudes of effect across years.Final seed predation is the combination of seed encounter and seed exploitation.Final seed predation could be either positively or negatively density-dependent and was contingent on the magnitude of the difference between positive density-dependent seed encounter and negative density-dependent seed exploitation.Our results also indicated that studies including only a few species would produce biased results,because the density effect on seed predation differed greatly among plant species.Future studies should include a large number of plant species that possess a wide range of diverse seed traits to avoid potential bias and produce more comprehensive and accurate results.展开更多
Background Direct seeding is potentially a more cost-effective alternative to conventional tree planting for restoring tropical forest ecosystems.However,seed loss,due to removal and damage by animals,can substantiall...Background Direct seeding is potentially a more cost-effective alternative to conventional tree planting for restoring tropical forest ecosystems.However,seed loss,due to removal and damage by animals,can substantially reduce seedling establishment.Therefore,this study examined the impact of seed predation on seedling establishment of five tree species,native to upland evergreen forests of northern Thailand:Hovenia dulcis,Alangium kurzii,Prunus cerasoides,Choerospondias axillaris and Horsfieldia amygdalina.We tested the hypothesis that excluding animals would significantly reduce seed removal,and increase both germination and seedling survival.The objective was to calculate a composite index of the relative suitability of the species studied for direct seeding.Methods Seeds were placed on the ground in a deforested site and subjected to five predator-exclusion treatments:wire cage,insecticide,cage+insecticide,open cage and no exclusion(control).Results Seed loss was highest for H.amygdalina(the largest seed tested).Across species,wire cages significantly reduced seed loss by 12.4%compared with controls(P<0.001)suggesting that vertebrates were the major seed predators.Seed germination ranged from 0 to 77%among the species tested.Based on relative species-performance scores(combining measures of survival and seedling growth),P.cerasoides was the most suitable species for direct seeding,followed by A.kurzii and C.axillaris,whilst H.dulcis and H.amygdalina were unsuitable.H.dulcis had small seeds with low seed germination,whereas H.amygdalina was subjected to high seed removal.Conclusion Exclusion of seed predators and the selection of suitable species may substantially increase the success of direct seeding,as a technique for restoring upland evergreen forest ecosystems.Testing more species for their suitability is needed,to provide more diverse options for forest restoration.展开更多
The impulse to remain profitable by increasing agricultural production levels in view of the greater demand for food, provided impetus to production intensification. The aim of this review is to summarise current lite...The impulse to remain profitable by increasing agricultural production levels in view of the greater demand for food, provided impetus to production intensification. The aim of this review is to summarise current literature, reporting specifically on the impact of production intensification on habitats and yield constraints caused by weeds. Secondly, in alleviating these effects over the short term, ecological measures that enhance species diversity in conserved habitats and promote semi-natural habitats in the agricultural landscape, are discussed. In large-scale intensive agriculture, weed control is predominantly rooted in agrochemical applications in the form of herbicides. Long lasting intensive agricultural practices show discord both with the promotion of the biodiversity of microbes belowground and aboveground and with organisms involved in the breaking down of plant material. The presence of native species in the surroundings, in combination with hedgerows and field margins, with a comparatively intricate and balanced variety of plants in a sheltered environment, are essential for settlement of benign insects, particularly in the face of intensive agricultural production. The promising tactic of advantageous seed predators enables decreased herbicide applications. Crop mosaics arranged to advance compatibility at the landscape scale are important to bolster pollination services and insect management, while ecological variety in the surroundings acts as a safety net for habitat diversity. Weed control in combination with different tactics of vegetation use, comprising cover cropping, hedgerows and field margins, sets up safe havens in the landscape, and improves the diffusion of complementary life forms. Field margins perform a meaningful natural function as point of provision for forage, safe havens and distribution passageways for pollinators and insect predators. Production practices that promote more heterogeneity and combine high density semi-natural safe havens and habitat conservation in agro ecosystems are beneficial to species diversity across trophic levels and contribute to agricultural production stability and food safety.展开更多
Some rodent-dispersed seeds have a hard seed-coat(e.g.woody endocarp).Specific scrapes or dental marks on the hard seed-coat left by rodents when they eat these seeds can be used to identify seed predators.In this stu...Some rodent-dispersed seeds have a hard seed-coat(e.g.woody endocarp).Specific scrapes or dental marks on the hard seed-coat left by rodents when they eat these seeds can be used to identify seed predators.In this study we measured the morphological traits of endocarp-remains of seeds of wild apricot Prunus armeniaca used by Chinese white-bellied rats Niviventor confucianus and Korean field mice Apodemus peninsulae.We established their Fisher's linear discriminant functions to separate endocarp-remains between the two predators.A total of 90.0% of the endocarp-remains left by Korean field mice and 88.0% of those left by Chinese white-bellied rats were correctly classified.The overall percentage of correct classification was 89.0%.One hundred and sixty endocarp-remains of unknown what species predated them were classified using the functions.The method may allow more reliable quantitative studies of the effects of Chinese white-bellied rats and Korean field mice on seed consumption and dispersal of wild apricot and this study might be used for reference in other studies of seed predators identification on hard seeds.展开更多
Large scale harvest of Korean pine （Pinus koraiensis） seeds as a food product in the mixed Korean pine-hardwood forest of northeastern China poses a serious threat to the sustainability and restoration of this endan...Large scale harvest of Korean pine （Pinus koraiensis） seeds as a food product in the mixed Korean pine-hardwood forest of northeastern China poses a serious threat to the sustainability and restoration of this endangered regional ecosystem. Seed collection over past decades greatly reduced the seed bank and subsequent seedling and sapling re- cruitment, and impacting a wide array of granivorous animals that rely on the pine seeds. We surveyed Korean pine seeds, including solid seeds （SS）, insect consumed seeds （ICS） and other （animal） consumed （OCS） kernels, of the seed bank （forest floor and the top 10 cm of mineral soil）, the seedlings and saplings from 1 m： sample plots in five forest types in Liangshui Nature Reserve （LNR） of the southern Xiao Xing＇an Moun- tains in northeastern China to provide accurate information for assessing the Korean pine regeneration potential. The average number of pine seeds in the seed bank were 11.2 seeds/m2, 9.1 seeds/m2, 4.6 seeds/m2, 1.1 seeds/m2, and 0.2 seeds/m2 in Korean pine-basswood forest, mixed Korean pine-hardwood forest, mixed conifer-hardwood forest, white birch forests, and oak forests, respectively. In the first three forest types, percentages of SS （potentially viable seeds） were 11.2%, 3.5% and 27.8%, respectively. The percentages of ICS （not viable seeds） were consistent at around 35%. The higher but variable percentages of OCS （not viable seeds） indicated high seed predation in these forests. Com- pared with other studies, we recorded higher percentages of seed damage, probably due to our survey approach and the increased depth of seed bank sampled in our study. Depletion of pine seeds in the seed bank greatly reduced seedling and sapling recruitment. Densities of pine seed- lings varied from about 180 trees/ha in the mixed Korean pine-hardwood forest to about 5,400 trees/ha in the mixed conifer-hardwood forests and showed a high degree of spatial variation. Saplings were rare in the mixed Korean pine-hardwood forest, but ranged in the thousands in other forests. Large scale pine seed harvest has seriously threatened the sustainability of the mixed Korean pine-hardwood forest ecosystem. Scaling down the seed harvest or supplemental planting of pine saplings are urgently needed to maintain the health of the existing Korean pine forests and to restore this endangered ecosystem.展开更多
Background:Predicting how natural and anthropogenic drivers shape different ecological indicators,such as plant populations along environmental gradients,can be a relevant tool for establishing management and conserva...Background:Predicting how natural and anthropogenic drivers shape different ecological indicators,such as plant populations along environmental gradients,can be a relevant tool for establishing management and conservation criteria of tropical wetlands.We aimed to assess the effects of seasonal flood disturbance,type of grasslands and topographical conditions on Croton trinitatis population distribution in a tropical wetland.Methods:The study was carried out in a seasonally flooded grassland(Central-West Brazil).We conducted samplings of soil on the dry and flood hydrophases of the Pantanal.We took the samples in eight seasonal ponds,with 1 km interval between them.Transects were marked during the flood period,observing the water level,one in the lowest zone,in the middle of the pond=low(ca.60 cm deep),one at the pond edge=mid(ca.30 cm deep)and one in the higher zone,on the external part=high(ca.1 cm deep).Results:The results showed that the topography,seasonality,and types of grassland determine differences in the abundance patterns of adult plants and seedlings,and seed bank and seed predation.The abiotic factors can shape plant population-related ecological processes and patterns,with outputs(germination and predation)and inputs(local dispersion and from neighbouring areas)of proportional seeds for the population maintenance in this environment.Conclusion:We emphasize the importance of these findings,to show that abiotic factors are not the only ones to be considered in ecological studies of distribution and structuring of populations in habitats with extreme seasonal events.展开更多
The Galápagos are considered a model oceanic archipelago,with unique flora and fauna currently threatened by alien invasive species.Seed dispersal is an important ecosystem function with consequences for plant po...The Galápagos are considered a model oceanic archipelago,with unique flora and fauna currently threatened by alien invasive species.Seed dispersal is an important ecosystem function with consequences for plant population dynamics and vegetation structure.Hence,understanding the seed dispersal abilities of the assemblages of frugivores will inform scientists and managers of the dynamics of plant invasions and improve management planning.Here we provide the first comprehensive review of published information on frugivory and animal seed dispersal in the Galápagos.We collected data from a variety of sources,including notes of the first naturalist expeditions,gray literature available only in Galápagos collections,and peer-reviewed journal articles.Plant–animal frugivorous interactions were retrieved from 43 studies and compiled into an interaction matrix describing 366 unique interactions.Most studies focused on fruit consumption as a driving force for natural selection,but seed fate was seldom considered.Although most(71%)of the interactions involved native plants,more than one-quarter(28%)involved introduced species.Interactions involving birds are considerably more common than those of reptiles and mammals,probably reflecting a research bias towards birds.Despite the historical importance of the archipelago as the laboratory for evolutionary and ecological research,understanding of its seed dispersal systems is limited.We end the review by suggesting 3 priority areas of research on frugivory and seed dispersal in the Galápagos:(i)target research to close knowledge gaps;(ii)the use of a network approach to frame seed dispersal at the community level;and(iii)evaluation of the effect of seed dispersal as a selective pressure acting upon plants and frugivores.Finally,the output of this research has to be properly delivered to the Galápagos National Park Services to help increase management effectiveness.展开更多
Scatter-hoarding rodents play a crucial role in seed survival and seed dispersal.As one of the most important seed traits,seed size and its effect on rodent–seed interaction attract lots of attention.Current studies ...Scatter-hoarding rodents play a crucial role in seed survival and seed dispersal.As one of the most important seed traits,seed size and its effect on rodent–seed interaction attract lots of attention.Current studies usually target one or a few species and show inconsistent patterns;however,few experiments include a large number of species although many plant species usually coexist in natural forest and overlap in fruiting time.Here,we tracked the dispersal and predation of 26100 seeds belonging to 41 tree species in a subtropical forest for 2 years.Most species showed no relationships between seed size and rodent foraging preference,while the remaining species displayed diverse of patterns:monotonic decrease and increase trends,and hump-shaped and U-shaped patterns,indicating that a one-off study with a few species might give misleading information.However,the seed size effect across species was consistent in both years,indicating that including a large number of species that hold a sufficient range of seed size may avoid the aforementioned bias.Interestingly,seed size effect differed among rodent foraging processes:a negative effect on seed harvest,a hump-shaped effect on seed removal and removal distance,while a positive effect on overwinter survival of cached seeds,indicating that rodents may make trade-offs between large and small seeds both among foraging processes and within a single process,thus lead to a parabolic relationship between seed size and seed dispersal success,that is medium-sized seeds were more likely to be removed and cached,and transported with a further distance.展开更多
Aims Theory suggests that species perform best at intermediate densities,where density-dependent facilitation and antagonism are balanced,but empirical evidence is scarce,particularly in plants.In a selfincompatible p...Aims Theory suggests that species perform best at intermediate densities,where density-dependent facilitation and antagonism are balanced,but empirical evidence is scarce,particularly in plants.In a selfincompatible perennial herb(Saussurea nigrescens),whose recruitment heavily relies on seed output,we test whether both intraspecific facilitation and antagonism significantly affect seed production,resulting in highest seed yield at an intermediate capitulum density.Methods Plots with different S.nigrescens densities were sampled in an Eastern Tibetan meadow during the growing season of 2012 to investigate the relationships between capitulum density and pollinator visitation rate,seed set ratio,parasite ratio,seed damage ratio,and capitulum size.Both simple linear and quadratic models were employed to determine the shape of relationships.Important Findings In line with general theory,hump-shaped relationships of capitulum density versus seed set ratio and number of florets per capitulum indicate intraspecific facilitation in sparse populations,which can be attributed to positive density-dependent pollinator visitation and the amelioration of detrimental physical factors.However,the proportion of seeds damaged by pre-dispersal predators increased monotonically with capitulum density,which may have—in combination with increased intraspecific competition for light and soil nutrients—resulted in density-dependent antagonism.Both positive and negative density-dependent agents acted simultaneously throughout the density range investigated and led to the highest seed yield at intermediate density levels in the Tibetan lotus.More efforts concurrently exploring the two effects are needed to facilitate understanding species abundance and community structure.展开更多
The early fossil record of terrestrial arthropod herbivory consists of two pulses. The first pulse was concentrated during the latest Silurian to Early Devonian （417 to 403 Ma）, and consists of the earliest evidence...The early fossil record of terrestrial arthropod herbivory consists of two pulses. The first pulse was concentrated during the latest Silurian to Early Devonian （417 to 403 Ma）, and consists of the earliest evidence for consumption of sporangia and stems （and limited fungivore borings）. Herbivorization of most of these tissues was rapid, representing 0 to 20 million-year （m.y.） lags from the earliest occurrences of these organs in the fossil record to their initial consumption （Phase 1）. For approximately the next 75 m.y., there was a second, more histologically varied origination and expansion of roots, leaves, wood and seeds, whose earliest evidence for herbivorization occurred from the Middle-Late Mississippian boundary to the Middle Pennsylvanian （327 to 309 Ma）. The appearance of this second herbivory pulse during the later Paleozoic （Phase 2） is accompanied by major lags of 98 to 54 m.y. between times of appearance of each of the four organ and tissue types and their subsequent herbivory. Both pulses provide a context for three emerging questions. First is an explanation for the contrast between the near instantaneous consumption of plant tissues during Phase 1, versus the exceptionally long lags between the earliest occurrences of plant tissues and their subsequent herbivorization during Phase 2. Second is the identity of arthropod herbivores for both phases. Third is the cause behind the overwhelming targeting of seed-fern plant hosts during Phase 2. Regardless of the answers to these questions, the trace fossil record of plant-arthropod associations provides primary ecological data that remain unaddressed by the body-fossil record alone.展开更多
Aims Several mechanistic hypotheses have been developed to explain the existence of alpine treelines worldwide.The reproduction limita-tion hypothesis(RLH)postulates that reproductive processes such as seed production...Aims Several mechanistic hypotheses have been developed to explain the existence of alpine treelines worldwide.The reproduction limita-tion hypothesis(RLH)postulates that reproductive processes such as seed production and dispersal are restricted in treeline envi-ronments,thereby limiting the establishment of new individuals in advance of extant treelines.Despite its popularity,no study has tested this hypothesis in a comprehensive fashion.In this experi-ment,we attempted to answer whether there are enough viable seeds being dispersed beyond treeline for sexually mediated tree-line advance,and what the implications of climate change might be on these processes.Methods We established 30 plots across two aspects(north vs.south)and three elevational habitats(forest,treeline and tundra)in a white spruce(Picea glauca)boreal forest-alpine tundra ecotone in south-west Yukon,Canada.In each plot,tree characteristics,seed produc-tion and predispersal damage were measured.Additionally,eight dispersal trays were positioned in each plot to measure seed rain,and germination trials with and without predation exclosures were constructed in a subset of plots to quantify dispersal and germina-tion success.Important Findings Results were highly variable both temporally and spatially.In 2014,a mast year,69%of adult trees produced cones compared to 0.4%in the following year.Higher density of trees in forest plots compared to treeline and tundra resulted in greater seed production at lower elevations.Across all plots,88%of seeds were damaged before dispersal or were not viable.Treeline plots had significantly greater predispersal damage.Seed rain was greater in south-facing plots than north-facing plots.Less than 2%of seeds produced on the landscape were dispersed into Tundra plots,located 50 m above treeline.There was a net movement of seeds from the north-facing slope to the south at our study site,likely due to prevailing winds during the dispersal period.Germination counts were more than double on north-facing slopes and one-third higher inside exclo-sures.Cumulatively,the results provide some evidence for the RLH.Collectively,the high amount of predispersal damage and non-viable seeds,variability associated with dispersal and significant seed predation can functionally influence treeline dynamics.These findings suggest that global treeline distribution models,which rely largely on temperature,may not be entirely accurate for predicting treeline advance-at least at finer temporal scales.Many stochas-tic factors need to align temporally for successful advance,which is likely to result in a lag of many decades between the period of temperature amelioration and an increased number of trees beyond extant treelines.展开更多
文摘As ecosystem degradation becomes more widespread, there is a growing need for efficient and effective forest restoration methods. Direct seeding is one such method that can be used to cover a relatively large area, particularly places with difficult-to-access terrain. One major obstacle hampering successful restoration via direct seeding is seed predation, as seeds are damaged or eaten. We tested the effectiveness of encrusting six species of native seeds with biochar-based coating in reducing the seeds’ chances of being predated on degraded hillsides and landslide scars in Hong Kong. The six seeded species are native trees and shrubs, including both late-successional and pioneer species that are present in forests and shrublands. Our results show that biochar-based seed coats were able to significantly reduce overall seed predation by 5.77% (SE = 1.41, p < 0.05). Additionally, we found varied effectiveness of the biochar-based seed coats across species and seed morphology. Of the six species that were included, four of them had significantly reduced seed predation after encrusting with biochar-based seed coats, while two other species were not significantly affected by the biochar-based seed coats. When we investigated seed predation against seed morphology, we found that while the species with larger seeds were more likely to be predated when sown without any biochar-based seed coat, the effectiveness of the biochar-based seed coat to reduce predation also increased with larger seeds. Our results suggest that encrusting seeds with biochar-based seed coats is an effective means of reducing seed predation.
基金This research was supported by the National Natural Science Foundation of China(31071929,31240470)the Knowledge Innovation Program of the Chinese Academy of Sciences(KSCX2-EW-N-05).
文摘By tracking the fate of individual seeds from 6 frugivore-dispersed plants with contrasting seed traits in a fragmented subtropical forest in Southwest China,we explored how rodent seed predation and hoarding were influenced by seed traits such as seed size,seed coat hardness and seed profitability.Post-dispersal seed fates varied significantly among the 6 seed species and 3 patterns were witnessed:large-seeded species with a hard seed coat(i.e.Choerospoadias axillaries and Diospyros kaki var.silvestris)had more seeds removed,cached and then surviving at caches,and they also had fewer seeds predated but a higher proportion of seeds surviving at the source;medium-sized species with higher profitability and thinner seed coat(i.e.Phoebe zhennan and Padus braohypoda)were first harvested and had the lowest probability of seeds surviving either at the source or at caches due to higher predation before or after removal;and small-seeded species with lower profitability(i.e.Elaeocarpus japonicas and Cornus controversa)had the highest probability of seeds surviving at the source but the lowest probability of seeds surviving at caches due to lower predation at the source and lower hoarding at caches.Our study indicates that patterns of seed predation,dispersal and survival among frugivore-dispersed plants are highly determined by seed traits such as seed size,seed defense and seed profitability due to selective predation and hoarding by seed-eating rodents.Therefore,trait-mediated seed predation,dispersal and survival via seed-eating rodents can largely affect population and community dynamics of frugivore-dispersed plants in fragmented forests.
基金supported by the Knowledge Innovation Project of the Chinese Academic of Sciences(KSCX2-SW-123)。
文摘Wild bananas are abundant in tropical areas and many ecologists have observed that the succession process is quicker following increased disturbance.This study was conducted to analyze animal–seed interactions and their effects on the seed fate of a wild banana species(Musa acuminata)in tropical southern Yunnan(China)through experiments considering spatial(site and habitat)and temporal(seasons)variation.The largest proportion of fruits(81%)was removed by frugivorous seed dispersers,especially by bats at nighttime.Only 13%of the fruits were removed by climbing seed predators(different species of rats).In the exclosure treatment,rodents accounted for a significantly higher total artificially exposed seed removal number than ants,but with spatial and temporal differences.The highest seed predation rate by rodents(70%)was found in forest with wild banana stands,corresponding with the highest rodent diversity(species numbers and abundance)among the habitat types.In contrast,the seed removal number by ants(57%)was highest in the open land habitats,but there was no close correlation with ant diversity.Seed removal numbers by ants were significantly higher in the dry compared to the rainy season,but rodent activity showed no differences between seasons.The overall results suggest that the largest proportion of seeds produced by wild banana are primarily dispersed by bats.Primary seed dispersal by bats at nighttime is essential for wild banana seeds to escape seed predation.
基金This study was supported by the Polish National Science Foundation grant Preludium no.2015/17/N/NZ8/01565while MB was supported by Polish Foundation for Science scholarship‘Start’,and Etiuda NSF grant no.2015/16/T/NZ8/00018+1 种基金DNA sequencing was supported by PLAGANADO AGL2014-54739-R awarded to RBMAS recognizes the support of the U.S.National Science Foundation(DEB-1556707).
文摘Species introduced to habitats outside their native range often escape control by their natural enemies.Besides competing with native species,an alien species might also affect the native herbivores by introducing a new source of different quality food.Here,we describe the case of northern red oak(Quercus rubra)invasion in Europe.We collected data on insect(moth Cydia spp.and weevil Curculio spp.)seed predation of northern red oak in its native(USA,North America)and invasive(Poland,Europe)range,as well as for sessile oaks(Quercus petrea)in Europe.We also evaluated the quality of acorns as hosts for weevil larvae by collecting infested acorns and measuring weevil developmental success,and quantifying acorn traits such as seed mass,tannins,lipids and protein concentration.We used DNA barcoding to identify insects to the species level.The predation by moths was similar and very low in both species and in both ranges.However,red oaks escape pre-dispersal seed predation by weevils in Europe.Weevil infestation rates of northern red oak acorns in their invasive range were 10 times lower than that of sessile oaks,and also 10 times lower than that of red oaks in North America.Furthermore,even when weevils oviposited into northern red oaks,the larvae failed to develop,suggesting that the exotic host created a trap for the insect.This phenomenon might gradually decrease the local abundance of the seed predator,and further aid the invasion.
基金the National Natural Science Foundation of China(31770570,31971444 and 31470494)the CAS“Light of West China”Program.
文摘Post-dispersal seed predation plays an important role in plant demography and biodiversity maintenance.However,the effects of seed density on seed predation from previous studies have been inconsistent.We dissected the effects of density on the 2-step processes of seed predation using 101520 seeds from 62 plant species in an alpine pine forest for 3 consecutive years.In this study we explained the current controversy surrounding the effects of density on seed predation.Seed encounter frequency(at least 1 seed being predated from an experiment depot)showed positive density dependence,while seed exploitation(the proportion of seeds being predated of the encountered depots)showed negative density dependence.Both density effects showed a consistent trend but with different magnitudes of effect across years.Final seed predation is the combination of seed encounter and seed exploitation.Final seed predation could be either positively or negatively density-dependent and was contingent on the magnitude of the difference between positive density-dependent seed encounter and negative density-dependent seed exploitation.Our results also indicated that studies including only a few species would produce biased results,because the density effect on seed predation differed greatly among plant species.Future studies should include a large number of plant species that possess a wide range of diverse seed traits to avoid potential bias and produce more comprehensive and accurate results.
基金This study was funded by the Thailand Research Fund(TRF Grant Number:MRG5980177),the Development and Promotion of Science and Technology Talents Project(Royal Thai Government Scholarship).Chiang Mai University partially supported this research,including the inputs of Stephen Elliott.
文摘Background Direct seeding is potentially a more cost-effective alternative to conventional tree planting for restoring tropical forest ecosystems.However,seed loss,due to removal and damage by animals,can substantially reduce seedling establishment.Therefore,this study examined the impact of seed predation on seedling establishment of five tree species,native to upland evergreen forests of northern Thailand:Hovenia dulcis,Alangium kurzii,Prunus cerasoides,Choerospondias axillaris and Horsfieldia amygdalina.We tested the hypothesis that excluding animals would significantly reduce seed removal,and increase both germination and seedling survival.The objective was to calculate a composite index of the relative suitability of the species studied for direct seeding.Methods Seeds were placed on the ground in a deforested site and subjected to five predator-exclusion treatments:wire cage,insecticide,cage+insecticide,open cage and no exclusion(control).Results Seed loss was highest for H.amygdalina(the largest seed tested).Across species,wire cages significantly reduced seed loss by 12.4%compared with controls(P<0.001)suggesting that vertebrates were the major seed predators.Seed germination ranged from 0 to 77%among the species tested.Based on relative species-performance scores(combining measures of survival and seedling growth),P.cerasoides was the most suitable species for direct seeding,followed by A.kurzii and C.axillaris,whilst H.dulcis and H.amygdalina were unsuitable.H.dulcis had small seeds with low seed germination,whereas H.amygdalina was subjected to high seed removal.Conclusion Exclusion of seed predators and the selection of suitable species may substantially increase the success of direct seeding,as a technique for restoring upland evergreen forest ecosystems.Testing more species for their suitability is needed,to provide more diverse options for forest restoration.
文摘The impulse to remain profitable by increasing agricultural production levels in view of the greater demand for food, provided impetus to production intensification. The aim of this review is to summarise current literature, reporting specifically on the impact of production intensification on habitats and yield constraints caused by weeds. Secondly, in alleviating these effects over the short term, ecological measures that enhance species diversity in conserved habitats and promote semi-natural habitats in the agricultural landscape, are discussed. In large-scale intensive agriculture, weed control is predominantly rooted in agrochemical applications in the form of herbicides. Long lasting intensive agricultural practices show discord both with the promotion of the biodiversity of microbes belowground and aboveground and with organisms involved in the breaking down of plant material. The presence of native species in the surroundings, in combination with hedgerows and field margins, with a comparatively intricate and balanced variety of plants in a sheltered environment, are essential for settlement of benign insects, particularly in the face of intensive agricultural production. The promising tactic of advantageous seed predators enables decreased herbicide applications. Crop mosaics arranged to advance compatibility at the landscape scale are important to bolster pollination services and insect management, while ecological variety in the surroundings acts as a safety net for habitat diversity. Weed control in combination with different tactics of vegetation use, comprising cover cropping, hedgerows and field margins, sets up safe havens in the landscape, and improves the diffusion of complementary life forms. Field margins perform a meaningful natural function as point of provision for forage, safe havens and distribution passageways for pollinators and insect predators. Production practices that promote more heterogeneity and combine high density semi-natural safe havens and habitat conservation in agro ecosystems are beneficial to species diversity across trophic levels and contribute to agricultural production stability and food safety.
基金funded by the National Natural Science Foundation of China(30800120) and the Foundation for New Teachers of Huazhong Normal University
文摘Some rodent-dispersed seeds have a hard seed-coat(e.g.woody endocarp).Specific scrapes or dental marks on the hard seed-coat left by rodents when they eat these seeds can be used to identify seed predators.In this study we measured the morphological traits of endocarp-remains of seeds of wild apricot Prunus armeniaca used by Chinese white-bellied rats Niviventor confucianus and Korean field mice Apodemus peninsulae.We established their Fisher's linear discriminant functions to separate endocarp-remains between the two predators.A total of 90.0% of the endocarp-remains left by Korean field mice and 88.0% of those left by Chinese white-bellied rats were correctly classified.The overall percentage of correct classification was 89.0%.One hundred and sixty endocarp-remains of unknown what species predated them were classified using the functions.The method may allow more reliable quantitative studies of the effects of Chinese white-bellied rats and Korean field mice on seed consumption and dispersal of wild apricot and this study might be used for reference in other studies of seed predators identification on hard seeds.
基金supported by the National Science Foundation of China (NSFC) grant (grants 30830024,30770330)
文摘Large scale harvest of Korean pine （Pinus koraiensis） seeds as a food product in the mixed Korean pine-hardwood forest of northeastern China poses a serious threat to the sustainability and restoration of this endangered regional ecosystem. Seed collection over past decades greatly reduced the seed bank and subsequent seedling and sapling re- cruitment, and impacting a wide array of granivorous animals that rely on the pine seeds. We surveyed Korean pine seeds, including solid seeds （SS）, insect consumed seeds （ICS） and other （animal） consumed （OCS） kernels, of the seed bank （forest floor and the top 10 cm of mineral soil）, the seedlings and saplings from 1 m： sample plots in five forest types in Liangshui Nature Reserve （LNR） of the southern Xiao Xing＇an Moun- tains in northeastern China to provide accurate information for assessing the Korean pine regeneration potential. The average number of pine seeds in the seed bank were 11.2 seeds/m2, 9.1 seeds/m2, 4.6 seeds/m2, 1.1 seeds/m2, and 0.2 seeds/m2 in Korean pine-basswood forest, mixed Korean pine-hardwood forest, mixed conifer-hardwood forest, white birch forests, and oak forests, respectively. In the first three forest types, percentages of SS （potentially viable seeds） were 11.2%, 3.5% and 27.8%, respectively. The percentages of ICS （not viable seeds） were consistent at around 35%. The higher but variable percentages of OCS （not viable seeds） indicated high seed predation in these forests. Com- pared with other studies, we recorded higher percentages of seed damage, probably due to our survey approach and the increased depth of seed bank sampled in our study. Depletion of pine seeds in the seed bank greatly reduced seedling and sapling recruitment. Densities of pine seed- lings varied from about 180 trees/ha in the mixed Korean pine-hardwood forest to about 5,400 trees/ha in the mixed conifer-hardwood forests and showed a high degree of spatial variation. Saplings were rare in the mixed Korean pine-hardwood forest, but ranged in the thousands in other forests. Large scale pine seed harvest has seriously threatened the sustainability of the mixed Korean pine-hardwood forest ecosystem. Scaling down the seed harvest or supplemental planting of pine saplings are urgently needed to maintain the health of the existing Korean pine forests and to restore this endangered ecosystem.
文摘Background:Predicting how natural and anthropogenic drivers shape different ecological indicators,such as plant populations along environmental gradients,can be a relevant tool for establishing management and conservation criteria of tropical wetlands.We aimed to assess the effects of seasonal flood disturbance,type of grasslands and topographical conditions on Croton trinitatis population distribution in a tropical wetland.Methods:The study was carried out in a seasonally flooded grassland(Central-West Brazil).We conducted samplings of soil on the dry and flood hydrophases of the Pantanal.We took the samples in eight seasonal ponds,with 1 km interval between them.Transects were marked during the flood period,observing the water level,one in the lowest zone,in the middle of the pond=low(ca.60 cm deep),one at the pond edge=mid(ca.30 cm deep)and one in the higher zone,on the external part=high(ca.1 cm deep).Results:The results showed that the topography,seasonality,and types of grassland determine differences in the abundance patterns of adult plants and seedlings,and seed bank and seed predation.The abiotic factors can shape plant population-related ecological processes and patterns,with outputs(germination and predation)and inputs(local dispersion and from neighbouring areas)of proportional seeds for the population maintenance in this environment.Conclusion:We emphasize the importance of these findings,to show that abiotic factors are not the only ones to be considered in ecological studies of distribution and structuring of populations in habitats with extreme seasonal events.
基金The present study was part of a biodiversity project funded by the BBVA Foundation(Spain).
文摘The Galápagos are considered a model oceanic archipelago,with unique flora and fauna currently threatened by alien invasive species.Seed dispersal is an important ecosystem function with consequences for plant population dynamics and vegetation structure.Hence,understanding the seed dispersal abilities of the assemblages of frugivores will inform scientists and managers of the dynamics of plant invasions and improve management planning.Here we provide the first comprehensive review of published information on frugivory and animal seed dispersal in the Galápagos.We collected data from a variety of sources,including notes of the first naturalist expeditions,gray literature available only in Galápagos collections,and peer-reviewed journal articles.Plant–animal frugivorous interactions were retrieved from 43 studies and compiled into an interaction matrix describing 366 unique interactions.Most studies focused on fruit consumption as a driving force for natural selection,but seed fate was seldom considered.Although most(71%)of the interactions involved native plants,more than one-quarter(28%)involved introduced species.Interactions involving birds are considerably more common than those of reptiles and mammals,probably reflecting a research bias towards birds.Despite the historical importance of the archipelago as the laboratory for evolutionary and ecological research,understanding of its seed dispersal systems is limited.We end the review by suggesting 3 priority areas of research on frugivory and seed dispersal in the Galápagos:(i)target research to close knowledge gaps;(ii)the use of a network approach to frame seed dispersal at the community level;and(iii)evaluation of the effect of seed dispersal as a selective pressure acting upon plants and frugivores.Finally,the output of this research has to be properly delivered to the Galápagos National Park Services to help increase management effectiveness.
基金funded by the National Natural Science Foundation of China(31971444 and 32171533).
文摘Scatter-hoarding rodents play a crucial role in seed survival and seed dispersal.As one of the most important seed traits,seed size and its effect on rodent–seed interaction attract lots of attention.Current studies usually target one or a few species and show inconsistent patterns;however,few experiments include a large number of species although many plant species usually coexist in natural forest and overlap in fruiting time.Here,we tracked the dispersal and predation of 26100 seeds belonging to 41 tree species in a subtropical forest for 2 years.Most species showed no relationships between seed size and rodent foraging preference,while the remaining species displayed diverse of patterns:monotonic decrease and increase trends,and hump-shaped and U-shaped patterns,indicating that a one-off study with a few species might give misleading information.However,the seed size effect across species was consistent in both years,indicating that including a large number of species that hold a sufficient range of seed size may avoid the aforementioned bias.Interestingly,seed size effect differed among rodent foraging processes:a negative effect on seed harvest,a hump-shaped effect on seed removal and removal distance,while a positive effect on overwinter survival of cached seeds,indicating that rodents may make trade-offs between large and small seeds both among foraging processes and within a single process,thus lead to a parabolic relationship between seed size and seed dispersal success,that is medium-sized seeds were more likely to be removed and cached,and transported with a further distance.
基金973 program(2013CB956300)National Science Foundation of China(31100397 and 3250004)‘Program for Changjiang Scholars and Innovative Research Team in University’(IRT_14R27).
文摘Aims Theory suggests that species perform best at intermediate densities,where density-dependent facilitation and antagonism are balanced,but empirical evidence is scarce,particularly in plants.In a selfincompatible perennial herb(Saussurea nigrescens),whose recruitment heavily relies on seed output,we test whether both intraspecific facilitation and antagonism significantly affect seed production,resulting in highest seed yield at an intermediate capitulum density.Methods Plots with different S.nigrescens densities were sampled in an Eastern Tibetan meadow during the growing season of 2012 to investigate the relationships between capitulum density and pollinator visitation rate,seed set ratio,parasite ratio,seed damage ratio,and capitulum size.Both simple linear and quadratic models were employed to determine the shape of relationships.Important Findings In line with general theory,hump-shaped relationships of capitulum density versus seed set ratio and number of florets per capitulum indicate intraspecific facilitation in sparse populations,which can be attributed to positive density-dependent pollinator visitation and the amelioration of detrimental physical factors.However,the proportion of seeds damaged by pre-dispersal predators increased monotonically with capitulum density,which may have—in combination with increased intraspecific competition for light and soil nutrients—resulted in density-dependent antagonism.Both positive and negative density-dependent agents acted simultaneously throughout the density range investigated and led to the highest seed yield at intermediate density levels in the Tibetan lotus.More efforts concurrently exploring the two effects are needed to facilitate understanding species abundance and community structure.
文摘The early fossil record of terrestrial arthropod herbivory consists of two pulses. The first pulse was concentrated during the latest Silurian to Early Devonian （417 to 403 Ma）, and consists of the earliest evidence for consumption of sporangia and stems （and limited fungivore borings）. Herbivorization of most of these tissues was rapid, representing 0 to 20 million-year （m.y.） lags from the earliest occurrences of these organs in the fossil record to their initial consumption （Phase 1）. For approximately the next 75 m.y., there was a second, more histologically varied origination and expansion of roots, leaves, wood and seeds, whose earliest evidence for herbivorization occurred from the Middle-Late Mississippian boundary to the Middle Pennsylvanian （327 to 309 Ma）. The appearance of this second herbivory pulse during the later Paleozoic （Phase 2） is accompanied by major lags of 98 to 54 m.y. between times of appearance of each of the four organ and tissue types and their subsequent herbivory. Both pulses provide a context for three emerging questions. First is an explanation for the contrast between the near instantaneous consumption of plant tissues during Phase 1, versus the exceptionally long lags between the earliest occurrences of plant tissues and their subsequent herbivorization during Phase 2. Second is the identity of arthropod herbivores for both phases. Third is the cause behind the overwhelming targeting of seed-fern plant hosts during Phase 2. Regardless of the answers to these questions, the trace fossil record of plant-arthropod associations provides primary ecological data that remain unaddressed by the body-fossil record alone.
文摘Aims Several mechanistic hypotheses have been developed to explain the existence of alpine treelines worldwide.The reproduction limita-tion hypothesis(RLH)postulates that reproductive processes such as seed production and dispersal are restricted in treeline envi-ronments,thereby limiting the establishment of new individuals in advance of extant treelines.Despite its popularity,no study has tested this hypothesis in a comprehensive fashion.In this experi-ment,we attempted to answer whether there are enough viable seeds being dispersed beyond treeline for sexually mediated tree-line advance,and what the implications of climate change might be on these processes.Methods We established 30 plots across two aspects(north vs.south)and three elevational habitats(forest,treeline and tundra)in a white spruce(Picea glauca)boreal forest-alpine tundra ecotone in south-west Yukon,Canada.In each plot,tree characteristics,seed produc-tion and predispersal damage were measured.Additionally,eight dispersal trays were positioned in each plot to measure seed rain,and germination trials with and without predation exclosures were constructed in a subset of plots to quantify dispersal and germina-tion success.Important Findings Results were highly variable both temporally and spatially.In 2014,a mast year,69%of adult trees produced cones compared to 0.4%in the following year.Higher density of trees in forest plots compared to treeline and tundra resulted in greater seed production at lower elevations.Across all plots,88%of seeds were damaged before dispersal or were not viable.Treeline plots had significantly greater predispersal damage.Seed rain was greater in south-facing plots than north-facing plots.Less than 2%of seeds produced on the landscape were dispersed into Tundra plots,located 50 m above treeline.There was a net movement of seeds from the north-facing slope to the south at our study site,likely due to prevailing winds during the dispersal period.Germination counts were more than double on north-facing slopes and one-third higher inside exclo-sures.Cumulatively,the results provide some evidence for the RLH.Collectively,the high amount of predispersal damage and non-viable seeds,variability associated with dispersal and significant seed predation can functionally influence treeline dynamics.These findings suggest that global treeline distribution models,which rely largely on temperature,may not be entirely accurate for predicting treeline advance-at least at finer temporal scales.Many stochas-tic factors need to align temporally for successful advance,which is likely to result in a lag of many decades between the period of temperature amelioration and an increased number of trees beyond extant treelines.
