The aquatic plant on the surface of the North Drainage Canal, pictured here, is azolla (some call it mosquito fern). Needless to say, it can completely take over the Conservancy’s managed marsh complexes, leaving them virtually useless as habitat for the one of the NBHCP’s two primary species, the giant garter snake. As an aquatic animal, the snake relies on smaller aquatic prey. But when there is a three-inch mat of azolla on a water channel, for example, the water chemistry changes so that there is no prey. I’ve even wondered if the snake can break through the cover of azolla, just to get air. Luckily, the photo here isn’t of the Conservancy’s preserves, but of the adjacent North Drainage Canal. The main reason I wanted to share it? Can you see the the footprints! For a mile up and down the North Drainage Canal, there are footprints easily seen on the surface of this water. On the “azolla” cap. Amazing. The Conservancy spends a lot of money trying to control azolla to keep the preserves fully functional for use by giant garter snakes. Wishes one of our covered species would eat it!
One Against Many?
The Conservancy uses a variety of tools to manage vegetation on its preserves, guided by a strategy known as “the soft path first.” One of those tools is grazing. Over the years, the Conservancy has used large grazing animals to manage marsh and adjacent upland vegetation, including Hereford, Black Angus, …