The seed shadow of oak ( Quercus liaotungensis Koidz.) was investigated in a broad_leaved deciduous forest in Dongling Mountain in 1997. The seed rain patterns under oak tree crown for three out of four oak trees fit...The seed shadow of oak ( Quercus liaotungensis Koidz.) was investigated in a broad_leaved deciduous forest in Dongling Mountain in 1997. The seed rain patterns under oak tree crown for three out of four oak trees fit quadratic distribution, with high coefficients of determination. For each of the four trees selected in this study the seed rain size estimated from the viable acorns collected from the traps deployed under the crown was low, ranging from 26 to 259. For each of the four oak trees, the average density of the seed rain under oak tree crown ranged from 0.76 to 7.26 seeds/m 2. The average seed rain density estimated from the acorns in the traps deployed randomly in the field was 1.57 seeds/m 2. After all viable acorns fell, the acorn ground density estimated from the acorns in the quadrats was 0.13 seeds/m 2, but no viable acorns were found on the ground under the tree crown of the four oak trees, although the area under the crown was over 5 folds than the area of the combined quadrats. These results indicated that a large number of acorns was removed or predated by vertebrates once the acorns fell on the ground and acorns predation was more intensive in the sites directly under the parent trees than the sites away from the parent trees; this supports the distance_dependent hypothesis. Of the total acorns of all four oak trees, the viable acorns only accounted for 18.1%, and 17.8% for acorns infected by insect larvae, 12.1% for immature acorns, 3.6% for decayed acorns, and the acorns predated by rodent directly in the crown was the highest, accounting for 48.4%. The proportion of acorns predated by animals including vertebrates and invertebrates amounts up to 78.3%, indicating that acorn predation by animals is a limiting factor affecting acorn survival before seed dispersal. The sustained time of viable acorn fall ranged from September 8 to October 3 for the four oak trees, with the peak between 16th and 26th September. The number of acorns was not significantly different among the four directions around the trunk base.展开更多
The sizes of both seed dispersers and seeds are traits that are likely to interact to influence seed fate in many synzoochoric plant species.Here,we examined whether members of a granivorous rodent community consist...The sizes of both seed dispersers and seeds are traits that are likely to interact to influence seed fate in many synzoochoric plant species.Here,we examined whether members of a granivorous rodent community consisting of species of different body size vary in their effectiveness as seed dispersers,and how this relationship may be altered by seed size.We marked northern red oak(Quercus rubra)acorns with plastic tags and placed them in size-selective rodent exclosures.The exclosures allowed differential access of rodent groups based on different body size:(i)small(e.g.Peromyscus spp.);(ii)small and medium(e.g.Tamias striatus);and(iii)small,medium and large(e.g.Sciurus carolinensis)species of rodents.Acorn removal did not differ among exclosure types,but more seeds were missing when removed by small rodents,probably because of larderhoarding.The treatments did not influence the relative frequency of acorn consumption.However,small rodents cached considerably fewer and partially ate more acorns than the other 2 groups.The mean dispersal distance was the longest for cages with medium openings,intermediate for cages with large openings and the shortest for cages with small openings.Acorn mass positively affected the probability of caching and this relationship was unaffected by exclosure type.In conclusion,granivorous rodents of different body sizes strongly differed in their interactions with acorns,with small rodents acting primarily as acorn predators and medium and large species contributing significantly more to dispersal of red oaks.展开更多
Animal-mediated seed dispersal is an important ecological process in which a strong mutualism between animals and plants can arise.However,few studies have examined how a community of potential seed dispersers interac...Animal-mediated seed dispersal is an important ecological process in which a strong mutualism between animals and plants can arise.However,few studies have examined how a community of potential seed dispersers interacts with sympatric seed trees.We employed a series of experiments in the Qinling Mountains in both semi-natural enclosure and the field to assess the interactions among 3 sympatric rodent species and 3 Fagaceae tree seeds.Seed traits all showed similar tannin levels but markedly different physical traits and nutritional contents.We found that seeds with heavy weight,thick coat,and high nutritional contents were less likely to be eaten in situ but more often to be eaten after dispersal or hoarded by rodents.These results support both the handling time hypothesis and the high nutrition hypothesis.Surprisingly,we also found that rodents,maybe,preferred to consume seeds with low levels of crude fiber in situ,and to harvest and hoard those with high levels of crude fiber for later consumption.The sympatric rodent species,Cansumys canus,the largest rodent in our study,harvested and hoarded more Quercus variabilis seeds with high physical and nutritional traits,while Apodemus draco,the smallest rodent,harvested more Q.serrata seeds with low physical and nutritional traits,and Niviventer confucianus harvested and hoarded more Q.aliena seeds with medium physical and nutritional traits.Our study demonstrates that different seed traits play different roles in influencing the seed fate and the shaping of mutualism and predation interactions within a community of rodent species.展开更多
Seeds of many plant species are secondarily dispersed by dung beetles,but the outcome of this interaction is highly context-specific.Little is known about how certain anthropogenic disturbances affect this plant-anima...Seeds of many plant species are secondarily dispersed by dung beetles,but the outcome of this interaction is highly context-specific.Little is known about how certain anthropogenic disturbances affect this plant-animal interaction.The aims of this study were to assess the effect of dung type on secondary dispersal by dung beetles in a forest fragment,and to determine whether this interaction is affected by edge effects.Using pitfall traps,we captured dung beetles attracted to dung of 2 frugivorous mammals:woolly monkeys and howler monkeys.We found differences between both dung beetle assemblages,but these differences were not consistent in time.Using seeds surrounded by both dung types,we carried out a field experiment using seeds of 2 plant species.We found that the probability of secondary dispersal by dung beetles was higher for seeds placed in woolly monkey dung.Finally,we carried out a field experiment using plastic beads as seed mimics to assess edge effects.We found that secondary seed dispersal by dung beetles was negatively affected by edges.The disruption of plant-animal interactions along anthropogenic forest edges could have long-term negative effects on forest dynamics by affecting processes of regeneration.展开更多
Deforestation and thinning are human activities that can destabilize the forest ecological system and,consequently,impact significantly on habitat and behavior of forest-dwelling animals.This hypothesis was test...Deforestation and thinning are human activities that can destabilize the forest ecological system and,consequently,impact significantly on habitat and behavior of forest-dwelling animals.This hypothesis was tested in Yugong in the Mount Taihangshan area by comparing the tracks of tagged seeds of Armeniaca sibirica.in sites of unthinned and thinned forests.Our results showed that:(i)the diversity of vegetation and rodents drastically reduced in sites with thinned forests,compared to unthinned sites;(ii)the amount of both removed and scatter-hoarded seeds significantly declined in sites with thinned forests,compared with the unthinned sites;(iii)there was no significant difference observed in the distance of seed dispersal between the thinned and unthinned areas;and(iv)the thinning did not show a significant change to the model of cache size.These results suggested that the thinning of forests negatively influenced the species richness and food-hoarding behavior of rodents.In addition,the results indicated that the weakened scattered-hoarding might be disadvantageous to seedling recruitment and forest restoration.展开更多
文摘The seed shadow of oak ( Quercus liaotungensis Koidz.) was investigated in a broad_leaved deciduous forest in Dongling Mountain in 1997. The seed rain patterns under oak tree crown for three out of four oak trees fit quadratic distribution, with high coefficients of determination. For each of the four trees selected in this study the seed rain size estimated from the viable acorns collected from the traps deployed under the crown was low, ranging from 26 to 259. For each of the four oak trees, the average density of the seed rain under oak tree crown ranged from 0.76 to 7.26 seeds/m 2. The average seed rain density estimated from the acorns in the traps deployed randomly in the field was 1.57 seeds/m 2. After all viable acorns fell, the acorn ground density estimated from the acorns in the quadrats was 0.13 seeds/m 2, but no viable acorns were found on the ground under the tree crown of the four oak trees, although the area under the crown was over 5 folds than the area of the combined quadrats. These results indicated that a large number of acorns was removed or predated by vertebrates once the acorns fell on the ground and acorns predation was more intensive in the sites directly under the parent trees than the sites away from the parent trees; this supports the distance_dependent hypothesis. Of the total acorns of all four oak trees, the viable acorns only accounted for 18.1%, and 17.8% for acorns infected by insect larvae, 12.1% for immature acorns, 3.6% for decayed acorns, and the acorns predated by rodent directly in the crown was the highest, accounting for 48.4%. The proportion of acorns predated by animals including vertebrates and invertebrates amounts up to 78.3%, indicating that acorn predation by animals is a limiting factor affecting acorn survival before seed dispersal. The sustained time of viable acorn fall ranged from September 8 to October 3 for the four oak trees, with the peak between 16th and 26th September. The number of acorns was not significantly different among the four directions around the trunk base.
基金supported by(Polish)National Science Centre grant 2012/04/M/NZ8/00674.
文摘The sizes of both seed dispersers and seeds are traits that are likely to interact to influence seed fate in many synzoochoric plant species.Here,we examined whether members of a granivorous rodent community consisting of species of different body size vary in their effectiveness as seed dispersers,and how this relationship may be altered by seed size.We marked northern red oak(Quercus rubra)acorns with plastic tags and placed them in size-selective rodent exclosures.The exclosures allowed differential access of rodent groups based on different body size:(i)small(e.g.Peromyscus spp.);(ii)small and medium(e.g.Tamias striatus);and(iii)small,medium and large(e.g.Sciurus carolinensis)species of rodents.Acorn removal did not differ among exclosure types,but more seeds were missing when removed by small rodents,probably because of larderhoarding.The treatments did not influence the relative frequency of acorn consumption.However,small rodents cached considerably fewer and partially ate more acorns than the other 2 groups.The mean dispersal distance was the longest for cages with medium openings,intermediate for cages with large openings and the shortest for cages with small openings.Acorn mass positively affected the probability of caching and this relationship was unaffected by exclosure type.In conclusion,granivorous rodents of different body sizes strongly differed in their interactions with acorns,with small rodents acting primarily as acorn predators and medium and large species contributing significantly more to dispersal of red oaks.
基金Funds were provided by the National Natural Science Foundation of China(32172436,31901085,31100283)the Shaanxi Natural Science Foundation(2021JQ-841)+3 种基金the Shaanxi Key Research and Development Program(2021NY-042)the Science and Technology Program of Shaanxi Academy of Sciences(2018K-04,2020K-21)the Science and Technology Innovation Program of Shaanxi Academy of Forestry(SXLK2020-0209)the Second Tibetan Plateau Scientific Expedition and Research Program(STEP,2019QZKK0501).
文摘Animal-mediated seed dispersal is an important ecological process in which a strong mutualism between animals and plants can arise.However,few studies have examined how a community of potential seed dispersers interacts with sympatric seed trees.We employed a series of experiments in the Qinling Mountains in both semi-natural enclosure and the field to assess the interactions among 3 sympatric rodent species and 3 Fagaceae tree seeds.Seed traits all showed similar tannin levels but markedly different physical traits and nutritional contents.We found that seeds with heavy weight,thick coat,and high nutritional contents were less likely to be eaten in situ but more often to be eaten after dispersal or hoarded by rodents.These results support both the handling time hypothesis and the high nutrition hypothesis.Surprisingly,we also found that rodents,maybe,preferred to consume seeds with low levels of crude fiber in situ,and to harvest and hoard those with high levels of crude fiber for later consumption.The sympatric rodent species,Cansumys canus,the largest rodent in our study,harvested and hoarded more Quercus variabilis seeds with high physical and nutritional traits,while Apodemus draco,the smallest rodent,harvested more Q.serrata seeds with low physical and nutritional traits,and Niviventer confucianus harvested and hoarded more Q.aliena seeds with medium physical and nutritional traits.Our study demonstrates that different seed traits play different roles in influencing the seed fate and the shaping of mutualism and predation interactions within a community of rodent species.
文摘Seeds of many plant species are secondarily dispersed by dung beetles,but the outcome of this interaction is highly context-specific.Little is known about how certain anthropogenic disturbances affect this plant-animal interaction.The aims of this study were to assess the effect of dung type on secondary dispersal by dung beetles in a forest fragment,and to determine whether this interaction is affected by edge effects.Using pitfall traps,we captured dung beetles attracted to dung of 2 frugivorous mammals:woolly monkeys and howler monkeys.We found differences between both dung beetle assemblages,but these differences were not consistent in time.Using seeds surrounded by both dung types,we carried out a field experiment using seeds of 2 plant species.We found that the probability of secondary dispersal by dung beetles was higher for seeds placed in woolly monkey dung.Finally,we carried out a field experiment using plastic beads as seed mimics to assess edge effects.We found that secondary seed dispersal by dung beetles was negatively affected by edges.The disruption of plant-animal interactions along anthropogenic forest edges could have long-term negative effects on forest dynamics by affecting processes of regeneration.
基金funded by the National Basic Research Program of China(No.2007CB109106)the Key Research Programs in Colleges and Universities of Henan Province(No.16A180039)the Postdoctoral Research Foundation of Zhengzhou University.
文摘Deforestation and thinning are human activities that can destabilize the forest ecological system and,consequently,impact significantly on habitat and behavior of forest-dwelling animals.This hypothesis was tested in Yugong in the Mount Taihangshan area by comparing the tracks of tagged seeds of Armeniaca sibirica.in sites of unthinned and thinned forests.Our results showed that:(i)the diversity of vegetation and rodents drastically reduced in sites with thinned forests,compared to unthinned sites;(ii)the amount of both removed and scatter-hoarded seeds significantly declined in sites with thinned forests,compared with the unthinned sites;(iii)there was no significant difference observed in the distance of seed dispersal between the thinned and unthinned areas;and(iv)the thinning did not show a significant change to the model of cache size.These results suggested that the thinning of forests negatively influenced the species richness and food-hoarding behavior of rodents.In addition,the results indicated that the weakened scattered-hoarding might be disadvantageous to seedling recruitment and forest restoration.