This is a Colorado endemic known from 43 locations. The species is threatened by biocontrol and other control efforts aimed at non-native thistles.
The primary threats to C. perplexans include the use of biological control and herbicides in the management of non-native Cirsium species, invasions of non-native plant species, and impacts from recreational, agricultural, industrial, and residential land
There are 29 principal occurrences documented in the Colorado Natural Heritage Program database. Five of the 29 occurrences have not been observed in over 20 years. The USFS Conservation Assessment documents 25 occurrences (Spackman Panjabi and Anderson 2004). Four new occurrences have been documented since the Assessment was published.
On USFS Sensitive Species list
Present research priorities include gathering baseline data on the distribution and population sizes for Cirsium perplexans. Identifying high quality occurrences of C. perplexans in which the size, condition, and landscape context are excellent will also help to prioritize conservation efforts for C. perplexans (Panjabi and Anderson 2004).
Understanding the breeding systems employed by Cirsium perplexans is another research priority for this species due to the practical and scientific value of such studies. Answers to questions about whether C. perplexans is apomictic or a frequent outcrosser will provide needed guidance for developing appropriate management practices. If C. perplexans reproduces predominantly through apomixis, the genetic population structure is more stable than if the species is an outcrosser, since a pollinator is not required. Thus, a trail or road through an apomictic population will not be as detrimental as one through a population of outcrossers (Panjabi and Anderson 2004).
The response of Cirsium perplexans to human impacts and disturbance has not been studied. Gaining practical knowledge of how to best manage populations of this species is of considerable importance given the rapid change in land use patterns, increasing recreational use, and increasing human population density of Colorados western slope communities (Panjabi and Anderson 2004).
Seed collection and storage.
Be the first to post an update!