| Rodent, mainly feed on plant seeds, would disperse seeds or store seeds when they feed on seeds to survive the food shortage period in the future. When storing seeds, rodents were preferred to bury them in the surface of the earth, which was more helpful to the seed germination. Sometimes, some buried seeds could not be discovered again, leaving only a small part of seeds germinating and becoming seedling eventually. During this process, the benefits plants get from these living seeds were much more than the costs caused by a lot of seeds predation by rodents. Rodents' hoarding behaviors were affected by many factors and they have to trade off among predation risk and energy benefit to attain maximum net income. There were a variety of edible seeds existing in the same forest at the same time, whose characteristics differed widely. What's more, these differences directly affected rodents' predation and storage strategy, which had important influence on plant survival and reproduction. Therefore, it was of important ecological significance to study the effect of different characteristics on rodents' behaviors, which also provided a reference on selecting trees in forest planting.In the fall of 2014 and the spring of 2015, the study was conducted in Dadaogou, Xin Jing Town, Jingyuan County of Liupan Mountain National Nature Reserve. Firstly, we investigate the local rodent species and abundance by straight-line clip method in night. Next, we took Quercus wutaishansea seeds and artificial seeds(made of peanut powder) as the research objects, and explored the effect of seed characteristics(seed size, tannin content and germination)?seed abundance?coverage handling?cached density and cached depth on seed removal and seed dispersal by rodents. Results were as follows:1) In Liupan Mountains, five species of rodents based on Apodemus peninsulae and Mus musculus were captured in 30-year-old Larix principis-rupprechtii plantation and six based on Apodemus agrarius and Apodemus peninsulae were captured in Q. wutaishansea bushwood. In different habits, the species and density of rodents differed greatly.There were mainly A. peninsulae, A.agrarius, M. musculus, Rattus niviventer, Microtus fords, Cricetulus longicaudatus, Ellobius talpinus and Scaptochirus moschatus in Liupan Mountains, among which A. peninsulae(39.3%) and A. agrarius(26.2%) were predominant species.2) In this paper, the seed abundance had a significant effect on the predation rate and hoarding rate after removal by rodents(P<0.05) and the seed consumption rate was slower in mast year than in non-mast year by rodents(P<0.05). The average distance of predation and hoarding after removal by rodents in the mast year was shorter(3.0 m and 4.9 m respectively) than that in the non-mast year(2.9 m and 4.6 m respectively)(P<0.05). The coverage treatment could not significantly affect predation in situ rate, while could significantly altered the seed predation rate and seed hoarding rate after removal(P<0.05), and slow down the seed consumption rate(F=18.976,df= 2,P=0.000).3) The result showed that seed size and tannin content had remarkable effect on seed predation rate and seed hoarding rate after removal by rodents(P<0.05), among which the interaction between them could significantly affect seed predation rate after removal(P<0.05). The seed predation and seed hoarding distance after removal of large seeds(4.7 m and 3.4 m respectively) were higher than that of small seeds(2.3 m and 2.4 m respectively)(P<0.05). Rodents preferred to transport middle-sized seeds(1.40 ±0.82 cm), the spread distance of which was further than that of large and small seeds. However, the effect of tannin content on disperse distance was not significant.4) The frequency of large seeds and small seeds had important influence on seed predation rate and storage rate after removal(P<0.05). Moreover, with the increase of seed frequency, the dispersal distance of seeds increased at first and then decreased. The seed predation and seed hoarding distance after removal of large seeds reached the largest(20.6 m and 18.3 m respectively) when the frequency was 0.4, while that of small seeds reached the highest(13.1 m and 12.0 m respectively) at the frequency of 0.6.5) The effect of seed germination on predation in situ rate, seed predation rate and storage rate after removal were not significant. The root-cutting proportion of germinal large seeds and small seeds were 91.4% and 86.8%, respectively.6) The proportion of cached seeds found by rodents could be significantly influenced by seed cached density(F=7.753,df=5,P<0.01), which was also directly proportional to seed cached density. When the density was 6.25 seeds/m2, the proportion of recached seeds reached the highest. The recached rate of seeds by rodents was proportional to cached density, while the dispersal distance of seeds increased at first and then decreased. The dispersal distance reached the furthest(8.4 m) at the density of 6.25 seeds /m2.7) As cached depth increased, the proportion of buried seeds found by rodents decreased gradually, that is to say, the correlation of them was significant negative(r=-0.152, P=0.042). At the depth of 5 cm, the proportion reached the lowest(14.4%) which was significantly lower than that of seeds with the other depth(P<0.05). |
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