Pectis imberbis A. Gray is an endemic plant species native to southern Arizona with fewer than 400 known individuals in existence. A total of 6 putative populations, each consisting of between ca. 10 and 180 individuals, occur at elevations of 1100-1700 m in a variety of habitats, including oak woodlands, desert grasslands, oak savannas, and disturbed areas in Arizona (road cuts, arroyos) (USFWS 2012). In the past, populations were also identified in Mexico (Keil 1978, USFWS 2012); however, Mexican populations have not been relocated in recent years (Keil 1982, Falk and Warren 1994, Sanchez-Escalante 2018a, 2018b). Resurveys of known P. imberbis sites suggest significant decline in abundance over the last two decades and have documented the extirpation of 9 populations and 1 sub-population. Initial decline of P. imberbis is believed to have resulted from overgrazing by domesticated livestock; other potential threats include competition with non-native species, increased drought severity and frequency, mining, road construction, and recreational activities (Phillips et al. 1982). In addition to these extrinsic stressors, rarity itself may reinforce population decline by reducing per capita reproduction (the Allee effect) and decreasing offspring viability when inbreeding results in the expression of deleterious alleles. Currently, little is known about the breeding system, lifespan, survival, or reproductive rates of P. imberbis, and no comprehensive assessment of P. imberbis pollinators has been conducted. Obtaining this basic biological knowledge is a critical and urgent first step towards developing an effective recovery plan for this species, which is currently on a trajectory towards extinction. The objectives of this project is to 1. Perform a comprehensive demographic analysis of P. imberbis; 2. Conduct a breeding system assessment of P. imberbis; and 3. Monitor pollinator visitation of P. imberbis.
