Community Ecology Study On Small Animals And Their Parasitic Fleas In Baima Snow Mountain National Nature Reserve

ObjectiveTo understand the community structure,spatial distribution and ecological characteristics of small mammals and their parasitic fleas in Baima snow mountain national nature reserve in Yunnan province.MethodsThe systematic epidemiological investigation on the small mammals and fleas were carried out in 30 sample point of reserve from June 2012 to May 2014 according to the terrain,altitude and other natural environmental conditions in reserve.The 30 sample points were classified into 5 vertical gradients.The community characteristics,vertical distribution,ecological characteristics and differential parasitism of small mammals and fleas were analyzed by community ecological indicators.Results(1)A total of 8149 effective clips were set,captured 1282 small mammals,which classified into 32 species of 21 genera in 6 families of 4 orders,the capture rate was14.6%.The largest number was rodents,representative as Apodemus draco,Apodemus latronum and Eothenomys custos,accounting for 58.57% of all the small mammals.While1252 fleas were collected and classified into 34 species of 16 genera in 9 subfamilies of 4family,the largest number were hystrichopsyllidae and leptopsyllidae,representative as Ctenophthalmus(Sinoctenophthalmus)yunnanus,Frontopsylla(Frontopsylla)diqingensis and Neopsylla specialis dechingensis,accounting for 67.78% of all the fleas.(2)α diversity analysis showed that: the highest richness of small mammals appeared in the middle altitudes with B gradient(yunnan pine-alpine pine forest),C gradient(needle leaf mixed forest zones),but the dominant population,change along the altitude and gradually replace.The overall evenness was high,diversity index peaked in B gradient.The richness and the diversity index peak of fleas was located in the D zone(dark coniferous forest zone of high altitude),but dominant species in each vertical zone was not significant.Compared with small mammals,the evenness of fleas was lower,the dominant species were more prominent.The species-abundance analysis also showed that the evenness of the small herds was higher than that of the flea community,and the ecological dominance was lower than that of the flea community.(3)β diversity analysis and Jaccard similarity analysis showed that the adjacent gradient was between medium similarity and medium dissimilarity,and the substitution rate was low.The highest similarity of small mammals was between B and C gradient,while fleas were between C and D gradient.With the environmental gradient span became larger,the substitution rate between the high and low altitude became faster,the types and number of substitutions increased,and the similarity decreased.(4)Niche analysis showed that the niche widths ofApodemus latronum,Apodemus draco,Eothenomys custos,Niviventer confucianus were the largest,15 species of small animals,such as Soriculus caudatus,were 0.There were 22 pairs of significant overlapping species in the niche overlap index,most of which was overlapped with Apodemus latronum,Apodemus draco,Ochotona thibetana.The spatial niche and nutritional niche of fleas indicated that the niche width ofNeopsylla honora honora,Rhadinopsylla(Actenophthalmus)dahurica vicina,Doratopsylla jii,Ctenophthalmus(Sinoctenophthalmus)lushuiensis,Frontopsylla(Frontopsylla)tomentosa,Pa radoxopsylla intermedius,Paradoxopsylla longiprojectus was 0.The overlap index of Neopsylla specialis specialis and Neopsylla specialis dechingensis,Neopsylla specialis specialis and Ctenophthalmus(Sinoctenophthalmus)yunnanus.The overlap index between Peromyscopsylla himalaica sichuanoyunnana and Macrostylophora bispiniforma bispiniforma was 0.(5)The parasitism differential analysis showed that the largest parasitic flea was Ctenophthalmus(Sinoctenophthalmus)yunnanus,parasitic on Eothenomys custos,account for72%of all the parasitic fleas.Conclusions(1)The overall community diversity of the small mammal and parasitic flea in Baima snow mountain national nature reserve was relatively high and evenly distributed.The community constructive of small mammals in different gradients and slopes was quite different.The species composition,quantity distribution,dominant species and rare species of small mammals and their parasitic fleas showed obvious different distribution,which was related to the high heterogeneity of landscape space in nature reserves.(2)The dominant populations of small mammals and fleas in the adjacent altitudes overlapped and crossed with each other,and the dominant population was replacement with the change of environmental gradient from the valley to the top gradually.(3)The richness and diversity index of small mammals was single-peak distribution pattern.The peaks were located in B gradient and C gradient in the middle elevation area.The peaks of flea richness and diversity index are located in D gradient in the high-altitude area,and the distribution patterns were single-peak and valley-peak respectively.(4)The similarity of small mammals was peak-valley distribution,and the peak is located between the BC gradient,while the flea was distributed in one peak,and the peak was located between the CD gradient.They are all moderately similar.The substitution rate was low between adjacent gradient,but with the environmental gradient span became larger,the substitution rate became higher,and the similarity was lower.(5)The flea rate,flea index and the species of fleas were different in each small mammals,which might be related to the selectivity of fleas to the host and the parasitic mode.The flea rate and flea index of Anourosorex squamipes were the highest,and the species and number of fleas were the largest in the Eothenomys custos,mainly was Ctenophthalmus(Sinoctenophthalmus)yunnanus.(6)Dominant species and common species have larger niche widths and stronger competitiveness.The difference of altitude,habitat and parasitism affected niche overlapindex.(7)Although Apodemus chevrieri,Marmota himalayana,Neopsylla specialis specialis,Frontopsylla(Frontopsylla)spadix spadix do not occupied the optimal positon in this survey,they can still created conditions for the spread of plague bacteria and form new foci.so In developing desease prevention and control measure of rat and flea spread diseases,we should fully considered the community structure,distribution pattern and ecological characteristics of small mammals and parasitic fleas.Continue to carry out investigation and monitoring,expand the scope of investigation,do appropriate to eliminate harmful host,control the media,intervention foci,long-term and sustainable strategy development for disease control.