Large-scale salvage logging is being conducted in the aftermath of the March 2016 storm that struck the monarch overwintering colonies in Mexico. This has an extremely damaging effect by degrading the protective canopy of the fir forest and increasing the exposure of the monarchs to cold, wind, rain, and snow. In addition, the organic matter that would have decomposed naturally in the forest has now been removed and will likely increase erosion of the forest soils.

The three adjacent photos are from El Rosario, which is the sanctuary that supports the largest colony of overwintering monarchs. The drone photo, taken around 1 May, is of salvaged logs in the Rosario parking area. The two logging photos were taken on 10 May.

The evidence is that the March 2016 storm was climatically severe and caused substantial mortality of monarchs this winter. We have weather data, photos, and personal communications to support this assertion. The report by Monarch Watch that over a thousand monarchs tags were recovered before the March storm suggests that there was significant mortality earlier in 2016, too, but we do not have climatic evidence of this yet and alternative explanations are possible. The reduction of the protective forest and increasing severity of storm events through climate change increases the wintertime hazards for monarchs and decreases their survivorship.

Reports to Journey North from Texas through 9 May 2016 show fewer returning monarchs than in the past two years, 2014 and 2015. The low level of spring sightings — coupled with photographic evidence from Texas of returning monarchs in unusually poor condition with severely damaged wings— suggest that the March storm in Mexico caused high levels of mortality and morbidity. We are concerned about the potential effects of the extensive winter mortality on the successful re-establishment of the 2016 spring and summer populations. 

The optimism of the 28 February 2016 New York Times article is now questionable. Time will tell.