Wednesday, August 8, 2018

The explained and unexplained decline of rare plants

Little by little,  fewer individuals of some listed plants are visible here.
First came the Giant Orchids, which went from 25 to 0 as a result of the heavy equipment used for mechanical clearing before the site's first burn in 2008.
Last year some heavy tractor work along the north fire lane in the south tract made 300 Polygonella basiramia disappear, at least temporarily.

The latest decline involved Scrub blazing star (pictured above), which was a common sight along the north-south trail in the north tract. This week, at the height of the flowering period,  I found only one.
The area along the path had been mechanically cleared within the past year.
The U.S. Fish and Wildlife Service's recovery plan for this species  recommends preventing this plant being run over by off-road vehicles. I assume this would apply to equipment used for bush-hogging falls into this category.
I found a small group of about 7 plants along a new cleared path east of the path.
I have been unable to find any west of the path where the most were located during a survey about 10 years ago.
I don't have any idea why those plants are missing.
Anyway, the total number from the earlier survey was 40 plants and now there are about a half a dozen.
This merits a further examination.