Spatial Pattern Of Monochamus Alternatus Population

Monochamus ahernatus as the major insect vector of pine wood nematode plays important roles not only in the old Infected Area pine wood nematode disease spreaded controlled by the East Asian monsoon System,but also in the new foci emerged on Wanding and Ruili controlled by the South Asian monsoon.Therefore,the effective regulation of M. alternatus is the key link to controlling pine wood nematode disease.Based on large datum in the field and the SPOT-5 satellite images,we systematically analysis the characteristics of spatial pattern and the Response Process to habitats landscape of M.ahernatus using 3S technology and space analysis method,in the light of the biological characteristics of M. alternatus and the present natural environment in Wangding,Yunnan province.The main results are as follow:1.The distribution of M.alternatus were significantly affected by the environmental factors including the distance closest to the highway(L_h),the distance closest to the residential point(L_r),altitude,slope position,and the average height(H_s) and diameter(D_s),the rate of total number(RN_s) and diameter of host SiMao pine(RD_s).Principal component analysis of such factors shows that there are four major factors effecting the distribution of population for M. alternatus.They are human disturbance factors comprising L_h and L_r,host dominance factors comprising N_s,D_t,RN_s and RD_t,terrain factors including slope gradient and position,and host growth potential factors including the H_s and D_s of SiMao pine.2.Spatial autocorrelation analysis shows that the Moran's I of population for M. alternatus was significantly negative autocorrelation both within the range of 100m to 200m and 500m to 650m,suggesting that the population for M.ahernatus was distributed in patch unevenly.Meanwhile,the number and the total diameter of SiMao pine within the range of 100m to 200m,and the canopy density,RNs and Dt for SiMao pine of whole woods within the range of 500m to 600m,were significantly negative autocorrelation in the same condition, respectively.The spatial distribution of M.alternatus is highly consistent with environmental factors in Pinus kesiya var.langbianensis landscape.It is similar that the spatial autocorrelation of spatial distribution for highway and residential point were both significantly positive autocorrelations in the scale of 300 meters,but significantly negative autocorrelation in large ones(550m to 1000m).3.There was no obvious population quantity variation without edge effect in the scale of 20 meters,but significantly increase affected by edge positive effect in the range of 20 to 50 meters for Monochamus alternatus from the P.kesiya var.langbianensis edge.The canopy density and the Ns of the P.kesiya var.langbianensis patches had increasing trend from edge zone to core area,so did.The variation of vegetation coverage was unstable from edge zone to core area,but had obvious decrease trend in the range of 20 to 50 meters.The D_s and H_s had great variational amplitude in the scale of 40 meters,especially in the range of 10 to 20 meters, but relatively steady far from 40 meters.The P.kesiya var.langbianensis occupy prodigious proportion reaching over 80%,both in the range of 20 to50 meters and 60 to 70 meters, according to the ratio of diameters.4.There were significant differences of distribution for M.alternatus among three patches' edges.The least individual number was in Shrub-SiMao pine with the average 2.45 individuals each trap,which in broadleaf forest-SiMao pine takes second place,and the most was in woods Path-SiMao pine with the average 9.52 individuals each trap.Both canopy densities and D_s were various among tree patches' edges.The canopy density was the most, and the host D_s was the least in Shrub-SiMao pine,but those in woods-path were completely opposite.5.By using Geostatistics and GIS,the population spatial pattern characteristic of M. alternatus study,reveals that the exponential model was served the population variation function fitting curve of M.alternatus(Rss=0.919,r~2=0.101),and the Sill value was 1.030 while the Nugget value was 0.001.It is continuous of population spatial distribution for M. alternatus within the range(93m),and the intensity decreased along with the distance,which 99.9%derived from the phenomena spatial autocorrelation.The population distribution Fractal Dimension D=1.986±4.564(r~2=0.01) close to 2,demonstrates that the spatial variation of population quantity occurred mainly in minor scale,but various environmental factors which affect M.alternatus will be more variation in large scale.