Background: Myrcianthes coquimbensis is an endangered shrub endemic to Chile. No published account is known about its biology, ecology or threats to its continued existence.

Aims: To document the current state of knowledge of M. coquimbensis regarding its geographic distribution, and population and reproductive parameters, and to evaluate threats in its distribution range.

Methods: Historical records and recent survey data of 110 localities were used to characterise its known distribution. Plots were established in seven localities to determine the proportion of flowering individuals, recruitment and estimate population size and structure. Finally, levels of post-dispersal seed predation were determined in one locality.

Results: The current distribution of M. coquimbensis extends along 82.8 km of the Chilean coast, where the species is mainly threatened by habitat loss. Only 13% of the individuals flowered during 2010, and 66% of these plants lost their entire flower crop due to desiccation. Few seeds (7.5%) were lost to post-dispersal seed predation. The populations are composed mainly of adult plants (70% of the individuals), and little to no recruitment was observed.

Conclusions: M. coquimbensis populations are threatened by habitat loss and are not naturally recruiting through sexual reproduction. This exemplifies a case where studies on the ecology of a species are urgently needed to be able to design effective conservation and management plans.