Study On Bamboo Landscape Pattern In The Giant Panda Habitat Of Haitang River Basin,Taibai Mountain

The plant community is rich in the giant panda(Ailuropoda melanoleuca)habitat of Haitang river basin located in Taibai Mountain,where there are Fargesia qinlingensis,Bashania fargesii and Fargesia dracocephala under the forest.F.qinlingensis has been extensively flowering,that makes the bamboo forest fragmented in recent years.Investigating the characteristics of plant community structure in the thress bamboo forests mentioned above and studying the dynamic change of F.qinlingensis forest landscape pattern after flowering,the spatial associations between main tree species and F.qinlingensis as well as the coping strategy of giant panda,which can provide references for the protection as well as management of the giant panda habitat.Therefore,based on the transect line and sampling method,this study simultaneously conducted a specific investigation using the infrared camera trap technology.The main results are as follows:(1)Compared F.qinlingensis forest with B.fargesii forest and F.dracocephala forest,the average height and base diameter of F.qinlingensis forest were lower but the average density was higher.There were significant differences in elevation,shrub coverage,shrub height,bamboo basal diameter and herb height between F.qinlingensis forest and B.fargesii forest.The species richness index showed B.fargesii forest>F.qinlingensis forest,but the Simpson dominance index,the Shannon-Wiener diversity index and the Pielou evenness index were opposite.As for F.qinlingensis forest and B.fargesii forest,the species richness index of different levels displayed arbor layer<shrub layer<herb layer,whereas the Simpson dominance index was shrub layer<arbor layer<herb layer,the Shannon-Wiener diversity index and the Pielou evenness index were arbor layer<herb layer<shrub layer.(2)In Betula albo-sinensis forest community grew in Taibai Mountain,the population of B.albo-sinensis was the largest showing an incresing trend.The population of Pinus armandiiis was relatively young and its structure was stable.The population of Salix matsudana,Populus davidiana and Abies fargesii was obviously declining.These five major tree species distributed randomly at large scales.The remnant F.qinlingensis showed significantly aggregated distributions at small scales and uniform distributions at medium scales.Different species showed significant correlation at medium or small scales and had no correlation at large scales.B.platyphylla,S.matsudana and P.armandiiis were positively associated with the remnant F.qinlingensis at large and medium scales,whereas A.fargesii were negatively associated with the remnant F.qinlingensis at large scales.(3)The bamboo landscape pattern has changed after the bamboo had flowered.The landscape types of F.qinlingensis distributed more even(increased SHEI and SHDI values)from 2013 to 2016.The bamboo forest landscape pattern became more fragmented(increased NP and FN values,decreased MPS values)and more regular in shape(decreased MSI values)during the first three years,but less fragmented,more irregular in shape by 2016.Correspondingly,the giant panda adopted the“out-back”coping strategy,indicating that the panda was maily observed between the altitude range of 2250-2450 m from 2013-2014;while in 2015,it moved to the higher altitude along the river when MPS and FN values of flowering bamboo patches were higher than 1.0 hm~2and 10.0 in its habitat that distributed in the altitude range of 2350-2450 m.However,it returned to the original feeding sites within the altitude range of 2280-2630 m after the 65.46%bamboo blossomed in 2016.Along with the flowering bamboo death,the giant panda left the original feeding sites,but it marked its territory in 2460 m.The height and basal diameter of F.qinlingensis forest were lower than B.fargesii forest and F.dracocephala forest,but the density was higher in the giant panda habitat of Haitang river basin located in Taibai mountain.The species diversity of F.qinlingensis forest and B.fargesii forest showed the same regularity at different levels.After the F.qinlingensis flowering,the spatial distribution patterns of the remnant F.qinlingensis showed significantly aggregated distributions at small scales and uniform distributions at medium scales.B.platyphylla and A.fargesii were positively or negatively associated with the remnant F.qinlingensis at large and medium scales,respectively.The landscape types of F.qinlingensis distributed more even and its degree of fragmentation increased firstly and then decreased.The giant panda adopted the strategy of“out-back”.