The Study On Bird Population Density,Effective Half-Strip Width Of Line Transect And Their Influencing Factors In Some Inland Areas Of Guangxi

Birds have a significant ecological status in nature,and they play a very important role in various fields related to the ecological environment in one way or another.To understand the dynamics of bird populations and communities,standardized research methods and long-term observations and studies are indispensable.Therefore,strengthening the methods and studies on the distribution of bird populations and related surveys and detections are not only important for bird conservation,but also beneficial for biodiversity conservation.At present,most of the studies conducted using Distance Sampling software focus on estimating the population density of endangered species,but the environmental and other factors affecting population density,detection function curve and effective detection distance are less reported.In this study,the field survey records of birds with various parameters from the Bird Ecology Laboratory of Guangxi Normal University in the past6 years were used as the data base,and the survey data under different data truncation levels were analyzed by Distance Sampling software to grasp the distribution of bird population density and effective detection distance in the construction area of inland wind farms in Guangxi.The data were analyzed by Distance Sampling software at different data truncation levels in order to grasp the distribution of bird population density and effective detection distance in the inland wind farm construction area of Guangxi,to provide preliminary data support for future research on the impact of wind farm projects on bird survival,and to provide reference for future population density estimation of relevant birds and selection of field survey methods.The main results are as follows.(1)The birds recorded in this study belong to 201 species of 15 orders and 48 families respectively,including two species of national-level key protected wildlife and 28 species of national-level two key protected wildlife.(2)The bird diversity indices of Guangxi inland wind farm construction area are as follows:Shannon-Wiener index is 4.01,Simpson index is 0.97,Inverse Simpson index is 33.40,and Pielou evenness index is 0.76;the diversity in the southern area is smaller than that in the northern area,which may be due to the less sample sites set up and not widely distributed in the southern area;the elevation in the The bird diversity index was higher in the180 m-250 m range of the survey area.(3)The total density of birds in all survey areas was 500.7 birds/km~2,with an effective sample width(ESW)of 54.235 m.The density of finches was 481.79 birds/km~2,with an ESW of 49.093 m.The density of birds in the southern area was 605.07 birds/km~2,with an ESW of 49.543 m.The density of birds in the northern area was 506.00 birds/km~2,with an ESW of 49.543m.The density of birds in the southern area was significantly higher than that in the northern area.(4)The population density of 76 species of birds in 7 orders and 33families was estimated by using Distance Sampling software,including 7species of birds with secondary national priority protection;the bird species with the highest overall population relative density in all regions was the sparrow(Passer montanus),the bird species with the highest density in the southern region was the red-eared bulbul(Pycnonotus jocosus)in the southern region,and the most densely populated bird species in the northern region was Pycnonotus sinensis.(5)The bird population density was greatest in the farmland habitat and the effective detection distance(EDR)was greatest in the Arbor forest habitat.The largest population densities in Arbor forest habitat,Shrubbery habitat and Residential area habitat were for Bulbulidae,the largest population relative density in farmland habitats was for Spotted Bunting(Lonchura punctulata),and the largest population relative density in freshwater habitats was for Pachycidae.The fact that different birds have different preferences for habitat types proves that the conservation of birds requires the protection of the habitats they depend on.(6)The different habitat types led to different values of ESW for birds in the sample line survey.Analyses of covariance and correlations revealed that the ESW values of birds in the sample line survey were not only closely related to bird body length(r=0.642,p-value<0.01),but also influenced by habitat type and habitat distribution in the survey area.Bird body length and Arbor forest habitat cover(r=0.449,p-value<0.01)were the most significantly correlated with ESW values,followed by Farmland habitat(r=-0.253,p-value<0.05)and Residential area habitat(r=-0.229,p-value<0.05).Controlling for the variable of body length,birds had the largest ESW values in Arbor forest habitat and the smallest ESW values in Residential area habitat,demonstrating the superiority of the Variable-distance Line-transect method from a habitat perspective.(7)Considering that the population density of birds may be affected by various objective factors including habitat type changes(such as geographical location,temperature and elevation),it is suggested that when using the Line-transect method to survey birds in the field,homogeneous short-distance lines can be set as far as possible,supplemented by other survey methods such as point-transect method and interview survey method to make the final survey results more objective and comprehensive.