| Mongolian oak (Quercus mongolica) is a valuable second class tree species in our country, and is one of the major broadleaf tree species in the forest area in Northeast of China, has highly economic and ecological values. Regeneration of Mongolian oak population has been affected by rodents on predation, removal and dispersal. In this paper, the Mongolian oak’s seed banks, seedling banks, seed predation and removal of Mongolian oak by rodents were studied in four mixed plantations, Manchurian walnut (Juglans mandshurica), Scotch pine (Pinus sylvestnis), Northeast China ash (Betula platyphylla) and White birch (Fraxinus mandshurica) of City forestry demonstration base of Northeast Forestry University form2010to2012. The effect of Mongolian oak’regeneration by rodents was explored. The results showed as followed:1. In four mixed plantations, the total seed predation rate and removal rate of Mongolian oak by rodents respectively were4.1±11.5%and20.6±33.8%. Mongolian oak seed predation rate and removal rate (7.1±15.3%and30.1±36.5%) were the highest in Scotch pine forest. Seed remaining rate (83.2±32.8%) was the highest in Manchurian walnut forest.2. Mongolian oak seed predation rate (P>0.05) had not significantly different in0m,10m,20m,30m,40m,50m distance groups that were apart from edge of Mongolian oak forest, removal rate and remaining rate (P<0.05) had significant difference in2010. Seed predation rate (P<0.05) had significant difference at different distance group, removal rate and remaining rate (P>0.05) had not significantly different in2011. But predation rate、removal rate and remaining rate (P<0.05) had significant difference in2012. Mongolian oak seed predation rate (6.0±14.6%) was the highest at20m, the highest removal rate (27.2±34.3%) was at10m, and the highest remaining rate (85.4±30.9%) was at0m.3. There was significant difference in Mongolian oak seed predation rate (P<0.05) in the three years. The removal rate of Mongolian oak seed by rodents in2010was significantly higher than2011and2012. There were37.8±49.7%,27.7±49.8%and8.5%±25.2%in2010,2011and2012, respectively.4. The survey of seed banks, in addition to the Northeast China ash forest was not founded vitality Mongolian oak sceds. We founded a small amount of vitality Mongolian oak seeds in four mixed plantations in three years. The density of vitality Mongolian oak seed and seed production had directly relation. The higher seed production, the density of vitality Mongolian oak seed was higher. The presence of these vitality seeds in the soil seed banks illustrated that hoarding behavior of rodents have promoted dispersal of seeds and seedling establishment, that provided strong evidence.5. The density of Mongolian oak seedling were significant difference (P<0.05) in different forest type in three years. Scotch pine forest had maximum density, followed by White birch forests Northeast China ash forest and Manchurian walnut forest. The result was consistent with the result of predation, removal and hoarding by rodents in four mixed plantation. The average proportion of the number of annual seedlings respectively were44.7%、49.3%and38.1%in2010、2011and2012.Winter food shortages could be the main reason that caused Mongolian oak seed had large predation stress by rodents. This kind of foraging strategy for survival objectively has created the conditions for seeds resources’dispersal and natural regeneration of Mongolian oak. The result show that, although the rodent has a certain predation pressure on Mongolian oak seed, but their behavior of dispersed storage on seeds has positive effect on Mongolian oak seed dispersal, Seedling distribution and population regeneration. |
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