Crossosoma 34(2), Fall-Winter 2008 
54 
extent, except during the best years. Surveys for presence/absence of M. shevockii 
should only be undertaken when M. shevockii can be reliably found by field 
botanists, as confirmed by visiting known reference locations. Surveys conducted 
in poor years, or out of season, may lead to a false conclusion that M. shevockii is 
absent from a given project site. Land use decisions and subsequent development 
based on such surveys could lead to extirpation of undocumented M. shevockii 
occurrences. 
The majority of Mimulus shevockii s known occurrences are within ca. one 
mile of each other, in Kelso Creek Valley (Fraga 2007). Prior to development 
within the Kelso Creek Valley region, gene flow may have been frequent between 
proximal populations. Mimulus shevockii is likely pollinated by small insects that 
travel relatively short distances. Small soft wing flower beetles ( Trichochrous ) 
have been observed visiting flowers. The flight path of small insects such as 
Trichochrous may be impeded by the construction of roads and houses among 
populations. Habitat fragmentation may therefore be inhibiting gene flow, leaving 
populations isolated and vulnerable to genetic impoverishment. However, little 
is known regarding inter-population pollinator movements, and flight capabilities 
remain poorly understood for most pollinators (Pasquet et al. 2008). 
About half of the known occurrences of M. shevockii are found wholly or partly on 
private property; these occurrences are at greatest risk due to potential development 
or other land use changes. Several populations have been fragmented due to their 
proximity to developed areas. One large population (in terms of area of occupancy 
and number of individuals; E03) occupies an area entirely on private property 
that is proposed for development of homes (CNDDB 2009, Fraga 2007). 
When the conservation plan (Fraga 2007) was published, it made no 
recommendations to list this species as threatened or endangered under California 
or Federal Endangered Species Acts. In fact, it suggested that listing should 
only be considered after further investigation. Upon conducting additional field 
work, and reviewing land ownership patterns and threats, additional conservation 
measures seem necessary. I recommend that State and federal listing be considered 
to aid in conservation of this species, and that efforts to list M. shevockii under the 
California Endangered Species Act be prioritized due to threats to its occurrences 
on private property. Currently BLM is managing for this species in a manner that 
would not likely change appreciably under Federal listing. 
