Allium tribracteatum

Allium tribracteatum is an endemic with about 35 known occurrences in two counties. It is threatened by several activities including timber harvest, camping and recreation, off road vehicle use and some development.

Found in Alpine, Amador, Calaveras, El Dorado, and Tuolumne Counties, California (CNPS 2017).

Known from 31 occurrences.

Allium tribracteatum is most threatened by fire suppression and off-road vehicle use (ORV) (pers. comm. Margaret Willit). Near at least one occurrence shrubs are being removed to reduce the fire load and a chemical fire retardant is also being used (pers. comm. Margaret Willit). This chemical fire retardant could damage the very thin soil where this Allium grows and alter it in such as way that it's ability to hold and transfer water to plants might be damaged, let alone the chemical itself might be toxic to the plants.

Also, several occurrences are near or in the midst of ORV or motorcycle trails and are damaged as a result of vehicle use (CNDDB 2004, pers. comm. Margaret Willits). In areas where the ridges are particularly difficult to get to ORV users tend to create more trails to get to the top which could ultimately damage populations in the way of the new trail (pers. comm. Margaret Willits).

In addition, the following are also threats: sledding near plants, foot traffic, litter, camp site use including campfires, hay dumping, some plants are near powerlines, and one population is close to a staging area for controlled burns (CNDDB 2004).

The plants near the powerlines are also near roads and when it rains the water from the roads runs down and washes away the very thin soil where the population occurs. Late season sledding is also a problem, even though the area is closed to sledding. In early spring snow is not uncommon, and when the snow melts this species emerges, and if it snows again this species completely capable of surviving the snow. If sledders use the area for sledding during a snow after the species has emerged and they sled over the plants, they will ultimately be damaged or killed. Camping and foot traffic are problematic for this species too. Since this species grows on very thin volcanic soil any foot traffic on or even near the plants compacts the soil. Climate change is also a threat as warmer temperatures will change the species diversity in areas and will increase competition. Finally, the largest occurrences of this species has a helitack (helicopter landing spot) located in the middle of it (pers. comm. Margaret Willits).