3.1 Point Pelee Marsh
We found very low numbers of muskrat houses at Pelee over our four contemporary survey years between 2014-2019 as compared to the historic survey period from 1968-1980 (Fig. 3). The mean (SE) number of muskrat houses found at Pelee between 1968 and 1980, excluding incomplete survey zones and years, was 719 (202.9). The 95% confidence interval for house counts during these years was 267 to 1171. In contrast, we observed a mean (SE) house count of 47 (7.4) during 2014-2019, excluding the same zones as we did with the historic data set. The 95% confidence interval for the house counts during these latter years was 24 to 71.
Our contemporary surveys of Pelee represent a 93% decline in mean muskrat abundance from historic levels 40-50 years prior (Fig. 4). Retaining the count results for the excluded survey zones still resulted in a dramatic difference in the mean number of houses found between each survey period (791 historically vs. 80 recently) and a 90% decline in house numbers.