关键词: 边缘革蜱, 银盾革蜱, 最大熵模型, 地理信息系统, 环境变量因子

Abstract:

Objective To evaluate the habitat adaptability of Dermacentor niveus and D. marginatus, and to provide reference for the prevention and control of the two tick species and their disease transmission. Methods The distribution sites of D. niveus and D. marginatus in Xinjiang from 1980 to 2017 were collected from the distribution and diversity data set of tick species in China, and the distribution sites of the two tick species in Xinjiang from 2017 to 2021 were collected through China National Knowledge Infrastructure (CNKI), Baidu Academic, PubMed and other databases. Environmental variables were downloaded from the World Meteorological Database. The maximum entropy (MaxEnt) model was established with 75% data records as training subset and the remaining 25% as model evaluation subset. The main environmental variables were screened using the “Jackknife” method of MaxEnt model and the R software. MaxEnt species distribution prediction model and ArcGIS spatial analysis method were used to predict the breeding environment distribution of D. niveus and D. marginatus. The model output was presented using ArcMap 10.1, and the characteristics of ecological environment of the two tick species were predicted according to the response curves of bioclimatic variables plotted by MaxEnt model. Results A total of 46 and 64 distribution sites of D. niveus and D. marginatus were found from the screening, respectively, the area under the receiver operating characteristic curve (AUC) values of the model assessment test subsets of D. niveus and D. marginatus were 0.847 and 0.815, respectively. From the 19 environmental variables, 8 environmental factors were screened out, which affect the survival of D. niveus and D. marginatus. The natural habitat prediction showed that the suitable habitats for D. niveus in Xinjiang were in the Junggar Basin, the Turpan Basin and the Tarim Basin; the suitable habitats for D. marginatus were in the Junggar Mountains, the Tianshan Mountains and the Kunlun Mountains. The areas of non-suitable habitat, low suitable habitat, moderate suitable habitat and high suitable habitat for D. niveus accounted for 35.80%, 29.18%, 10.32% and 24.70% of the total area of Xinjiang; while those for D. marginatus accounted for 33.62%, 17.01%, 17.08% and 32.28%, respectively. By the Jackknife method, the data screening found that precipitation of the driest month (Bio14), seasonal temperature change (Bio4), and mean temperature of the wettest quarter (Bio8) were the main environmental variable factor of D. niveus distribution, while the precipitation of the driest quarter (Bio17), annual precipitation (Bio12) and precipitation of wettest quarter (Bio16) were the main environmental variable factor of the distribution of D. marginatus. The response curve of main environmental variables showed that when the Bio14 was 21 mm, the coefficient of variation of Bio4 was 1 510, and Bio8 was 20 ℃, the existence probability of D. niveus was the highest; when Bio17 was 71 mm, Bio12 was 230 mm and Bio16 was 269 mm, the existence probability of D. marginatus was the highest. Conclusion MaxEnt model established exhibits high prediction precision and accuracy. It was demonstrated that low altitude area was the preferable habitat for D. niveus, whereas the high altitude area was the preferable habitat for D. marginatus. The precipitation in the driest month was the main environmental factor affecting the two tick species; the temperature was the primary environmental variable affecting D. niveus distribution, and precipitation was the primary environmental variable affecting D. marginatus distribution.

Key words: Dermacentor niveus, Dermacentor marginatus, Maximum entropy model, Geographic information system, Environmental factor variable