Bugmyrin S V, Bespyatova L A, Korotkov Yu S
Institute of Biology, Karelian Research Centre, Russian Academy of Sciences, 11 Pushkinskaya St, Petrozavodsk, 185910, Russia.
Chumakov Federal Scientific Center for Research and Development of Immune and Biological Products, Russian Academy of Sciences, bldg. 1, 8, Institute for Poliomyelitis, Moscow, 108819, Russia.
Exp Appl Acarol. 2019 Feb;77(2):229-240. doi: 10.1007/s10493-019-00342-y. Epub 2019 Feb 13.
The article presents the results of long-term observations of variations in the abundance of Ixodes persulcatus, carried out since 1982, in the middle taiga subzone of Karelia. Adult questing ticks were collected from vegetation following standard flagging procedures. The time series was evaluated by singular spectrum analysis. Correlation coefficients were calculated for the observed tick abundances and meteorological data (mean daily air temperature and precipitation) for the current year and preceding years. Analysis of the time series revealed the trend and harmonic components with periods of 8, 2.5 and 4 years. Around 83% of the total variance is explained by the first principal component, which governs the general vector of change-a gradual reduction in I. persulcatus abundance from 2003 to 2017. Correlations between tick abundance and climatic indices were observed in all years and were associated with both temperature and precipitation. The greatest number of significant coefficients was obtained for correlations between tick abundance and weather conditions in the preceding season. An equation was suggested where tick abundance is described by a linear function with four variables: mean air temperature in April and July, total precipitation in February, and annual number of days with temperatures above 5 °С. Thus, the observed long-term dynamics are characterized by the following key patterns: a sharp population rise early in the 2000s, some recent decline (stabilization) of the abundance, the presence of quasi-periodic cycles, and a close correlation between tick abundance and climatic variables.
本文呈现了自1982年以来在卡累利阿中泰加亚区对全沟硬蜱丰度变化进行长期观测的结果。成年寻觅蜱按照标准拖旗法从植被中采集。时间序列通过奇异谱分析进行评估。计算了当年及前几年观测到的蜱丰度与气象数据（日平均气温和降水量）之间的相关系数。时间序列分析揭示了趋势以及周期为8年、2.5年和4年的谐波成分。约83%的总方差由第一主成分解释，该主成分控制着变化的总体向量——全沟硬蜱丰度从2003年到2017年逐渐下降。在所有年份都观察到蜱丰度与气候指数之间的相关性，且与温度和降水量都有关。在前一季的蜱丰度与天气状况之间的相关性中获得了最多的显著系数。提出了一个方程，其中蜱丰度由一个包含四个变量的线性函数描述：4月和7月的平均气温、2月的总降水量以及年平均气温高于5摄氏度的天数。因此，观测到的长期动态具有以下关键特征：21世纪初种群数量急剧上升、近期丰度有所下降（稳定）、存在准周期循环以及蜱丰度与气候变量之间密切相关。
