Effects Of Thinning On Seed Dispersal By Rodents In Secondary Forest

In the field, interference usually produces an important influence on populationdynamics and balance of ecosystem. As a common management strategy in forestryindustry, thinning could produce a significant impact and interference onforest-dwelling animals and their behavior. Therefore the study about the effect ofthinning on rodent’s seed hoarding behavior in the secondary forest could providecertain theoretical reference for management and regeneration of forest in this area. InMt. Taihangshan area, we chose two types of secondary forests, thinning andcontrolling as our qudrats. From Apr.2012to Nov.2013,1200seeds of wild apricot(Prunus armeniaca) were released in spring and summer of each year, with a totalnumber of9600seeds of P. armeniaca;1000seeds of P. armeniaca and1000seeds ofQuercus variabilis were respectively released in autumn of the two years with a totalnumber of4000; After seed placing, seed fates influence by rodents were monitoredwith a interval of2days. And the results were showed below:(1) Rodents in the un-thinning secondary forest mainly were Apodemus peninsulae,Niviventer confucianus, Sciurotamias davidianus; and the same rodent species werefound in the controlling forest. In the controlling qudrat there were a total capture rateof15.98%and33.33%separately in2012and2013with a significant seasonaldifference, as in2012the capture rate in spring was the highest, and that in summer ishigher than autumn, but less than that in spring, while the capture rate declines insummer, autumn and spring in2013; and in the thinning plot the total capture rate in 2012and2013were4%and23.99%with differences in years and seasons, thecapture rates were: summer> spring> autumn in2012; while summer> autumn>spring in2013. And in the controlling forest the density of trees was0.48±1.15/m2,0.22±1.16/m2in the shrub; while the density of trees was0.21±0.88/m2, and thedensity of shrub increased as the time going.(2) In the thinning sample plot, there was no significant difference between thesurvival rate among seasons, it showed: summer> autumn> spring in the un-thinningsample plot in2013; thinning did not change the rodent’s hoarding mode, and rodentstill buried a number of P. armeniaca seeds; the average dispersal distance of the P.armeniaca seeds in2012and2013shown the same as autumn> summer> spring inthe controlling forest, while it shown the contrary in the thinning forest in2012asspring> summer> autumn.(3) In the controlling qudrat, there were no significant different between seeds of P.armeniaca. and Q. variabilis in their remaining dynamic, but the seeds of Q.variabilis diffused faster than seeds of P. armeniaca, in the thinning foret seeds of Q.variabilis also had a higher dispersal rate than P. armeniaca; in the controlling forest,the percentage of the buried seeds buried by rodent were36.33%for Q. variabilis and55.33%for P. armeniaca in2012, and19.33%and28.67%for Q. variabilis and P.armeniaca in2013. While in the thinning plot there were only six seeds of Q.variabilis and10%seeds of P. armeniaca being buried (scatter hoarded). In both ofthe two sample plots the percentage of seeds being buried shown that P. armeniacawas higher than Q. variabilis, and the number of seeds being buried declined afterthinning, while the seeds intact in situ increased;58.67%Q. variabilis and63.33%P.armeniaca were carried away from the seeds station less than5m in the thinning plot,while in the controlling area63%seeds were cached in a distance more than5m, andthe average dispersal distance of Q. variabilis seeds were shorter than P. armeniaca inboth of the thinning and controlling qudrats.(4) Forest thinning caused that the remaining dynamic of seeds of P. armeniacashown an inconsistent difference between the same season in two years. The dispersalrate of P. armeniaca seeds in spring was51.67%, which was significantly higher thanthat in2013, in the thinning area the persistence rate of P. armeniaca seeds in summer was0.33%in2013, which was significant lower than that in2012; the seeds fate of P.armeniaca was mainly buried both in2012and2013, and thinning did not the patternof sees fate of P. armeniaca; in spring, the average diffusion distance of P. armeniacaseeds was4.41（±0.31）m in2013, which was relatively shorter than11.71（±0.71）m in2012in the thinning forest, and in summer and autumn, the average diffusiondistance of P. armeniaca seeds in2013was relative further. The average diffusiondistance of P. armeniaca seeds in thinning plot was smaller than in controlling forestin different seasons except spring.