Skip to main content

Table 3 Monthly density of nymphs (DON) per 100 m2 for the four elevation sites on Chaumont Mountain over the 15 years of the study (2004–2018)

From: Beech tree masting explains the inter-annual variation in the fall and spring peaks of Ixodes ricinus ticks with different time lags

Site

Years

N

DON Mean

DON StdDev

DON Range

CND

DON2

Low

15

144

74.4

82.6

0.00–430.0

22,629

62.0

Medium

15

144

61.4

75.0

0.00–385.8

18,849

51.6

High

15

137

42.7

52.0

0.00–257.5

12,582

34.5

Top

15

133

10.6

14.5

0.00–80.8

3000

8.2

  1. Shown for each of the four elevation sites are the number of years, sample size (N; units are number of transects), mean, standard deviation, and the range of the monthly DON (units are nymphs per 100 m2). For each elevation site, the expected sample size is 180 transects; missing transects are due to snow days when dragging for ticks was not possible. The DON is biased high due to the missing values for the snow days. In our previous study [15], we calculated the cumulative nymphal density (CND) for each calendar year by integrating the area under the curve of the seasonal phenology of the DON (per 100 m2) from 1 January to 31 December. When this CND is divided by 365 days, it gives a second estimate of the density of nymphs (DON2) that is less biased by the missing snow days. For this reason, the estimates of DON2 are lower than the DON