Rank ReasonsHistorically known from 7 counties in northern California, but much of the species' limited, fragile habitat has been urbanized or converted to agriculture. It is now known from only 13 populations in 4 counties. Proposed residential projects threaten the 3 largest populations which contain over 70 percent of the individual plants. Other imminent threats related to urbanization affect most of the remaining populations.
Threat Impact CommentsOne of the primary threats to L conjugens is conversion of landuse, for example residential and industrial development, wetland drainage, and agricultural land conversion (including vineyards) (USFWS 2008). Since 65% of this species occurs on private land and is not protected, this is an ongoing problem (USFWS 2008). Just as significant are such associated threats as introduced invasive plants (like Italian ryegrass and waxy mannagrass), recreational uses (such as off-road, equestrian, and mountain bike traffic), road construction and widening, and the resulting habitat fragmentation (USFWS 2008). Other threats to the species include landfill expansion, gravel mining, and both intensive grazing practices and the lack of grazing (USFWS 2008). Moderate grazing (in stocking numbers, frequency, and duration) is important to keeping invasive plants in check and improving soil conditions when burning is not possible (USFWS 2008). Climate change, especially severe drought, is a real threat since this species depends on vernal pools for survival (USFWS 2008).