| From April 2015 to November 2018,in the temperate forest of Zhangguangcai Mountains,the forest of Hengdaohezi and Sandao were selected as the study sites,and the small rodents and representative tree species as the study object.The effects of rodents on seed predation,hoarding,dispersal and seed fate were studied,and a reciprocal coevolutionary relationship between rodents and plant seeds,at the same time,the main rodent foraging,hoarding behavior and the interaction with various tree seeds were studied.The main results are as follows:1.Investigation of rodent community diversity.The diversity of rodent community was investigated by ways of rat clip and cage.The results show that the capture rates by rat clip in Hengdaohezi and Sandao forest were 6.54%and 11.34%respectively,the capture rates by cage were 9.88%and 9.04%respectively.There is no signifcantly difference between the two methods.Infrared triggered camera technology can be used as a survey method for rodents.7 species of rodents were recorded:Apodemus peninsulae,Apode,mus agrarius,Clethrionomys rufocanus,Tscherskia triton,Microtus fortis,Tamias sibiricus,Sciurus vulgaris.The dominant species in Hengdaohezi forest was A.peninsulae.In broad-leaved forest and mixed forest,Apodemus peninsulae was the dominant species.The dominant species in Sandao forest were A.peninsulae and A.agrarius.The diversity index and evenness index of rodent community in Sandao forest were higher than those in Hengdaohezi.There were signifcantly differences in rodent diversity among different vegetation types.2.Traits of seeds selected by rodents.Some sympatric seeds selected in the temperate forests.The morphological traits and nutrient substance of different seeds were compared.Basic morphological traits of seeds and Traits of soeds consumed by rodents were compared.The results showed that there were significant differences in traits and nutrient between different seeds.And the traits and nutrient of different seeds affect the hoarding behavior of rodents.Seeds selection of rodents were based on the comprehensive evaluation of seed size,seed and kernel quality and ratio,seed coat thickness and hardness,nutrients and other components.The role of a single factor cannot be considered separately.The proportion of consumption of Rkoraiensis,C.mandshurica,and Q.mongolica by rodent were relatively high,while Asibirica and J.mandshurica were rarely consumed.3.Food preference strategies of four sympatric rodents.To understand the characteristics of rodent preferences for different seeds,we performed a semi-natural enclosure experiment with four rodent species(A.peninsulae,A.agrarius,T.triton,and C.rufocanus)and the seeds of seven tree species(Pinus koraiensis,Corylus mandshurica,Quercus mongolica,Juglans mandshurica,Armeniaca sibirica,Prunus salicina.and Cerasus tomentosa)to investigate the niche differentiation and resource utilization patterns of sympatric rodents.The results showed that the four rodent species exhibited different total consume rates on different seeds,but all had a high total consume rate on the seeds of P.koraiensis,C.mandshurica and Q.mongolica.However,the tested rodents exhibited differences in the priority by which they selected the seeds from different tree species.A.peninsulae loving to feed the seeds of Q.mongolica,C.mandshurica and P.koraiensis(Ei:0.328.0.219,0.192),and partial to Q.mongolica.A.agrarius loving to feed the seeds of C.mandshurica,Q.mongolica,.koraiensis and C.tomentosa(Ei:0.267,0.236,0.211,0.046),and partial to C.mandshurica.C.rufocanus loving to feed the seeds of P.koraiensis Q.mongolica,C.mandshurica and C.tomentosa(Ei:0.326,0.226,0.176,0.007),and partial to P.koraiensis;T.triton loving to feed the seeds of P.koraiensis,C.mandshurica.Q.mongolica,P.salicina and C.tomentosa(Ei:0.118,0.118.0.118.0.060.0.034).The results supported our hypothesis that sympatric rodents overlap in food selection.However,each rodent species has a marked food selection preference,and different rodent species differ in food preferences,reflecting the role of distinct food niche differentiation in their coexistence.4.Temporal and spatial changes of the scatter-hoarding strategies of rodents.Based on seeds investigation,scatter-hoarding strategies of rodents were studied in two different seasons and four different habitats respectively.The results show that:(1)Due to the lack of food resources in spring and the seeds are rich in autumn,rodents adopted different hoarding strategies:seed consumption was significantly different in different season,and seed consumption in spring was more and faster than that in autumn.In order to meet the need of energy supply in spring,rodents preyed more seeds(55.11%).In order to ensure the overwintering food demand in autumn,the proportion of dispersed seeds was larger(58.47%).Moreover,the dispersal distance of seeds were farther in autumn.(2)There were significantly different of the seed fate among different habitats:the consumption rate of seeds was the fastest in artificial pine forest,and it was the slowest in forest edge.Broad-leaved forest and mixed forest were close to each other.The proportion of seed consumption of P.koraiensis,C.maodshurica and Q.mongolica were 96.69%,99.10%and 93.07%respectively.The proportion of predation and dispersal were 48.62%and 48.07%respectively for P.koraiensis,23.32%and 75.78%for C.mandshurica,and 61.07 and 32.00%for Q.mongolica.In the forest edge,the proportion of predation of all seeds were the lowest(P.koraiensis 28.33%,C.mandshurica 15.83%,Q.mongolica 44.00%),and the proportion of dispersal were the highest(P.koraiensis 59.17%,C.mandshurica 84.17%,Q.mongolica 48.00%).The average dispersal distance of all seeds were less than 6 m.and there were significant differences of dispersal distance and burial depth in different habitats.(3)Rodents have different consumption strategies for different seeds.In general,the proportion of predation of Q.mongolica which are rich in nutrients and easy to deal with was the highest C.mandshurica which rich in nutrients,but the seed coat is thick and hard,has more dispersal proportionrtthe proportion of predation and dispersal of P.koraiensis were similar.5.Feeding behavior and scatter-hoarding strategy of Apodemus peninsulae.Taking the dominant species of A.peninsulae as the object,and the feeding behavior,activity rhythm and dispersed storage strategy of forest seeds in natural environment were studied by infrared camera.The results show that:(1)The nocturnal activity time of Apodemus peninsulae was 100%after sunset and 99.96%before sunrise.In different months,the starting and ending time of their activities were slightly different,the earliest activity time shows a trend of advance,the latest activity time shows a trend of delay.The feeding behavior spectrum includes motor behavior(creep,walk,skip)(57.96%).feeding behavior(forage,feeding,transport,hoarding and clean)(40.36%).and sentinel behavior(alert,flee,banishment and coexistence)(1.68%).(2)There was a significant difference in the average frequency of feeding activities per night,7.22±.8/night in August,29.7±7.8/night in September,and 15.7±7.5/night in October.The peak of feeding activity was from 18:00 to 23:00 every night,which was different among three months.The activity frequency on the first day of food encounter was the highest,with an average of 32.7717.1.Subsequently,the daily food intake frequency was between 10 and 22 times,and the trend was obviously different in different months.The correlation between feeding activity and temperature was not significant,but with light intensity.(3)There are obvious scatter hoarding behavior,different feeding and hoarding strategies for different seeds,seed size,seed kernel mass ratio,seed coat thickness and other seed traits and seed processing time affect the feeding and dispersal of seeds.In situ feeding seeds accounted for 15.09%,after handling feeding seeds accounted for 20.37%,transported hoarding seeds accounted for 41.20%,in situ intact seeds accounted for 23.33%.Q.mongolica(47.78%)was the nost abundant seed,followed by.koraiensis(37.60%)and C.mandshurica(14.62%).Seeds were distributed and hoarded near the seed source in many short distance and small hoarding sites.Most of the hoarding sites only stored one seed,which was buried 1?2 cm deep below the layer of weeds,dead branches,fallen leaves,shrubs and humus.There was no significant difference in the dispersal distance of different seeds,and the burial distance of the same seeds was greater than the distance between feeding after transportation and intact after transportation. |
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