Colorado Native Plant Society
John Marr Grant Committee
In the spring of 2012, I was awarded a $500 John Marr Grant to help complete a floristic survey in west-central Colorado (Floristic Survey of the Uncompahgre Basin and Greater Grand Mesa Area was the title of the grant proposal. While the title was modified later on, the area was the same as described in the proposal.). This study was conducted in pursuit of a master’s degree in botany through the Rocky Mountain Herbarium and Department of Botany at the University of Wyoming. As this was the only funding received for 2012, the rest of my 2012 field work was self-funded. Funding for previous field seasons came from the Bureau of Land Management and the University of Wyoming Department of Botany. During the summer of 2012, I was in the field from May 11 – September 20. A total 9,878 project miles were driven, 284 miles were walked, and 4,654 plants were collected during that field season. As 1,919 new taxa were collected during the summer of 2012, this season was very important to completion of the project. Below is a summary of the study’s findings.
Thank you again for your support of this project.
A vascular plant inventory was conducted of the Uncompahgre, Lower Gunnison, and Plateau Creek drainages of west-central Colorado during the field seasons of 2010-2012. The study covered an area of 4,335 sq mi (11,228 sq km) and comprised all or part of Delta, Gunnison, Mesa, Montrose, and Ouray counties. Significant physiographic features of the area included Grand Mesa, Dominquez and Escalante Canyons, Gunnison Gorge, the Uncompahgre Plateau and the northernmost San Juan Mountains. Lying within the Southern Rocky Mountain and Northern Canyonlands physiogeographic regions, elevation in the study area ranges from 4,616 ft (1,407 m) along Plateau Creek to the 14,150 ft (4,312 m) summit of Mount Sneffels. A total of 12,398 collections were made at 314 sites within the study area.
Because of regional physiography and local climatic conditions, the study area contains a wide variety of vegetation types and microhabitats. A total of 1,267 unique taxa were collected. These taxa were documented with voucher specimens, providing concrete data about taxon location, elevation, and phenology. These collections represent 38% of the statewide flora (Ackerfield 2015). Of these, 350 or 28% were “county records” – taxa that might be known, or presumed to be, in the area but were not represented in herbaria with specimens. Additionally, populations of two federally listed species were documented using photographs and GPS points.
Along with voucher specimens, the other major product of this study was a taxon checklist for the area. To present as complete a checklist as possible, a search of the COLO, SEINet, and RM databases was conducted, resulting in the addition of 303 taxa to the area checklist and bringing the number of families documented in the area to 101, with 1,572 taxa in 508 genera, which is 47% of the state flora. Considering the study area is only 4% of the state, it is indeed species rich. Additionally, many species of conservation concern were documented, including a West Slope record of Carex livida, a Forest Service sensitive species that is known from only three other counties in Colorado. Also, the first Colorado records of Agropyron bonaepartis, a non-native grass, were documented from five locations in the study area.
As a result of this inventory, baseline knowledge of the flora in the study area has increased considerably, especially that of plant biogeography. A specific illustration of this can be seen in the distributions of Achillea millefolium and Carex bella. Before this study, a virtual herbaria search (SEINet and COLO) for A. millefolium revealed only 28 records within the study area. The same search for C. bella resulted in just 8 collections. An additional 69 collections of Achillea millefolium and 15 collections of Carex bella were documented as a result of this study. These two taxa illustrate the increased sample size for the study area, resulting in a clearer idea of the relative abundance and distribution of all vascular plant taxa. Data on all study collections is available through the RM on-line database and SEINet.
Along with increasing general knowledge of plant biodiverity and species richness, data from this study have already been used in other ways. Information collected concerning species of conservation concern is being incorporated into the new revision of the Grand Mesa, Uncompahgre, and Gunnison National Forest Plan. The Colorado Natural Heritage Program has used information and photos to help develop a best management practices plan for Penstemon mensarum (Panjabi and Smith 2014), move Lomatium eastwoodiae to watchlist status, and update information on state-tracked sensitive species at the Colorado Rare Plant Symposium. Examination of voucher specimens in herbaria has led to state and county distribution corrections for several taxa. Duplicates of voucher specimens are being used by Jennifer Ackerfield for morphological and DNA studies of Cirsium. Voucher specimens from this study also contributed to species descriptions and keys for Ackerfield’s Flora of Colorado.
Still, since only 80% of the flora was actually vouchered, I would have to say that there are still questions to be answered. Those “missed” taxa, especially ones from historical collections, could be searched for, to see if they are indeed still in the area. Locations that were difficult to access could be explored; habitats that were less collected than others could be sought out and visited. Targeted searches for species of conservation concern would likely lead to discoveries of new populations, especially those that are most responsive to yearly weather events.
The flora of an area is a dynamic entity, constantly changing as new species are introduced and others are extripated. As the effects of climate change influence local weather patterns, the flora will respond. Human activities such as development, recreation and other land use will also affect the species composition of the area. Hopefully, the results of this inventory will provide a solid baseline for understanding those changes and support further biodiversity studies.