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- All Subjects: Floristics
- Creators: Pigg, Kathleen B
- Creators: Coburn, Francis S
Description
The Upper Verde River of central Arizona flows through a landscape of complex geology at the meeting of seven biotic communities and three physiographic provinces. This has resulted in notably diverse flora and fauna and a hub of rare and endemic plant species. The river has sustained cultures since pre-history, however current regional water use is predicted to diminish streamflow over the next century. Prior to this project, no floristic inventory had been conducted along any section of the Verde. The purpose of this study was to develop a Flora of the Upper Verde River, with the goals of documenting rare and endemic species, the composition and abundance of wetland plants, and the factors shaping plant diversity in the region.
I made a total of 1856 collections and reviewed past collections to produce a checklist of 729 vascular plant taxa in 403 genera and 98 families. The most species-rich family is the Poaceae, followed by Asteraceae and Fabaceae. The flora includes 159 wetland taxa, 47 endemics, and 26 taxa of conservation concern, eight of which are Federally listed. Several new populations were found in these categories and of rarely-collected taxa including one state record, three county records and several range extensions. I report on the local status of several endemics, wetland taxa with limited distributions, and relict populations of a tepary bean (Phaseolus acutifolius) that were likely transported to the region and cultivated by pre-Columbian cultures. I categorize thirteen distinct plant communities, the most abundant being Pinyon/Juniper Woodland, Chihuahuan/Apacherian Scrub, and Riparian Deciduous Forest.
Four primary factors influence floristic diversity of the Upper Verde region: 1) a location at the junction of three physiographic and floristic provinces—represented by co-occurrence of species with affinities to the Sonoran, Intermountain and Madrean regions, 2) geologic diversity—as distinct groups of species are associated with particular geologic types, 3) topographic and habitat complexity—allowing species adapted to disparate environments to co-occur, and 4) human introductions—since over 15% of the flora is composed of introduced species from Eurasia and several taxa were introduced to the region and cultivated by pre-Columbian cultures.
I made a total of 1856 collections and reviewed past collections to produce a checklist of 729 vascular plant taxa in 403 genera and 98 families. The most species-rich family is the Poaceae, followed by Asteraceae and Fabaceae. The flora includes 159 wetland taxa, 47 endemics, and 26 taxa of conservation concern, eight of which are Federally listed. Several new populations were found in these categories and of rarely-collected taxa including one state record, three county records and several range extensions. I report on the local status of several endemics, wetland taxa with limited distributions, and relict populations of a tepary bean (Phaseolus acutifolius) that were likely transported to the region and cultivated by pre-Columbian cultures. I categorize thirteen distinct plant communities, the most abundant being Pinyon/Juniper Woodland, Chihuahuan/Apacherian Scrub, and Riparian Deciduous Forest.
Four primary factors influence floristic diversity of the Upper Verde region: 1) a location at the junction of three physiographic and floristic provinces—represented by co-occurrence of species with affinities to the Sonoran, Intermountain and Madrean regions, 2) geologic diversity—as distinct groups of species are associated with particular geologic types, 3) topographic and habitat complexity—allowing species adapted to disparate environments to co-occur, and 4) human introductions—since over 15% of the flora is composed of introduced species from Eurasia and several taxa were introduced to the region and cultivated by pre-Columbian cultures.
ContributorsCoburn, Francis S (Author) / Stromberg, Juliet C. (Thesis advisor) / Landrum, Leslie R (Thesis advisor) / Makings, Elizabeth (Committee member) / Fertig, Walter F (Committee member) / Arizona State University (Publisher)
Created2015
Description
For this study, the flora of the northern section of the Lower Verde River, within the Tonto National Forest in Yavapai and Gila Counties, Arizona was documented and analyzed. The study site, part of the northern leading edge of the Sonoran Desert, encompasses about 16,000 hectares and is located approximately 45 miles north-northeast of Phoenix. The area, extends roughly 28 river miles from the East Verde River in the north to Chalk Mountain in the south and is largely only accessible by foot, or by boat, and as a result was previously extremely under-collected. Over a three-year study period, from August, 2017 to May, 2020, 835 plant specimens were collected and identified, representing 360 species which, combined with earlier herbarium specimens collected by others, resulted in 427 plant species found in the study area. The plant diversity of this remote region reflects three distinct vegetation communities: upland Sonoran Desert, perennial riparian corridor, and semi-desert grasslands. Together, these communities act as an important transition zone between the Sonoran Desert and higher elevation habitats. Perennial streams are biodiversity hotspots within the study area. For example, the 400 hectares of Red Creek that falls within the study boundaries contain 28% of the total species. The study site contains several plants of conservation importance including 12 species endemic to Arizona, 22 vulnerable or imperiled species, five US Forest Service sensitive species, and one Federally Endangered species. In order to compare the diversity of the Lower Verde River Flora to nine other similar/related floras in Arizona, a species-area curve using five different models was generated. The resulting models showed the Lower Verde River flora to be very close to, although slightly below, the species-accumulation curve which may indicate that roughly 50-100 species may yet be added to the flora. This prediction seems realistic, as there were several locations that could not be collected due to remoteness and excessive heat.
ContributorsLarson-Whittaker, Cole (Author) / Pigg, Kathleen B (Thesis advisor) / Salywon, Andrew (Committee member) / Hodgson, Wendy (Committee member) / Arizona State University (Publisher)
Created2020
Description
Baseline community composition data provides a snapshot in time that allows changes in composition to be monitored more effectively and can inform best practices. This study examines Arizona Upland plant community composition of the Sonoran Desert through three different lenses: floristic inventory, and fire and reseeding effects.
A floristic inventory was conducted at Cave Creek Regional Park (CCRP), Maricopa County, AZ. One hundred fifty-four taxa were documented within Park boundaries, including 148 species and six infraspecific taxa in 43 families. Asteraceae, Boraginaceae, and Fabaceae accounted for 40% of documented species and annuals accounted for 56% of documented diversity.
Fire effects were studied at three locations within McDowell Sonoran Preserve (MSP), Scottsdale, AZ. These fires occurred throughout the 1990s and recovered naturally. Fire and reseeding effects were studied at the site of a 2005 fire within CCRP that was reseeded immediately following the fire.
Two questions underlie the study regarding fire and reseeding effects: 1) How did fire and reseeding affect the cover and diversity of the plant communities? 2) Is there a difference in distribution of cover between treatments for individual species or growth habits? To address these questions, I compared burned and adjacent unburned treatments at each site, with an additional reseeded treatment added at CCRP.
MSP sites revealed overall diversity and cover was similar between treatments, but succulent cover was significantly reduced, and subshrub cover was significantly greater in the burn treatment. Seventeen species showed significant difference in distribution of cover between treatments.
The CCRP reseeded site revealed 11 of 28 species used in the seed mix persist 12 years post-fire. The reseeded treatment showed greater overall diversity than burned and unburned treatments. Succulent and shrub cover were significantly reduced by fire while subshrub cover was significantly greater in the reseeded treatment. Sixteen species showed significant difference in distribution of cover between treatments.
Fire appears to impact plant community composition across Arizona Upland sites. Choosing species to include in seed mixes for post-fire reseeding, based on knowledge of pre-fire species composition and individual species’ fire responses, may be a useful tool to promote post-fire plant community recovery.
A floristic inventory was conducted at Cave Creek Regional Park (CCRP), Maricopa County, AZ. One hundred fifty-four taxa were documented within Park boundaries, including 148 species and six infraspecific taxa in 43 families. Asteraceae, Boraginaceae, and Fabaceae accounted for 40% of documented species and annuals accounted for 56% of documented diversity.
Fire effects were studied at three locations within McDowell Sonoran Preserve (MSP), Scottsdale, AZ. These fires occurred throughout the 1990s and recovered naturally. Fire and reseeding effects were studied at the site of a 2005 fire within CCRP that was reseeded immediately following the fire.
Two questions underlie the study regarding fire and reseeding effects: 1) How did fire and reseeding affect the cover and diversity of the plant communities? 2) Is there a difference in distribution of cover between treatments for individual species or growth habits? To address these questions, I compared burned and adjacent unburned treatments at each site, with an additional reseeded treatment added at CCRP.
MSP sites revealed overall diversity and cover was similar between treatments, but succulent cover was significantly reduced, and subshrub cover was significantly greater in the burn treatment. Seventeen species showed significant difference in distribution of cover between treatments.
The CCRP reseeded site revealed 11 of 28 species used in the seed mix persist 12 years post-fire. The reseeded treatment showed greater overall diversity than burned and unburned treatments. Succulent and shrub cover were significantly reduced by fire while subshrub cover was significantly greater in the reseeded treatment. Sixteen species showed significant difference in distribution of cover between treatments.
Fire appears to impact plant community composition across Arizona Upland sites. Choosing species to include in seed mixes for post-fire reseeding, based on knowledge of pre-fire species composition and individual species’ fire responses, may be a useful tool to promote post-fire plant community recovery.
ContributorsBarron, Kara Lynn (Author) / Pigg, Kathleen B (Thesis advisor) / Stromberg, Juliet (Thesis advisor) / Makings, Elizabeth (Committee member) / McCue, Kimberlie (Committee member) / Arizona State University (Publisher)
Created2018