This study provides a broad, phylogenetic perspective on the evolution of the Campanulaceae clade. The remarkable habitat diversity and cosmopolitan distribution of this lineage appears to be the result of a complex history of genome duplications and numerous long-distance dispersal events. We failed to find evidence for an ancestral polyploidy event for this clade, and our analyses indicate an ancestral base number of nine for the group. This study will serve as a framework for future studies in diverse areas of research in Campanulaceae.

New, productive fluvial marshes may develop along regulated canyon rivers through reduction in flood frequency, thereby increasing diversity, production, and wildlife habitat availability. Few fluvial marshes occurred along the eddy‐dominated Colorado River in the Grand Canyon prior to construction of Glen Canyon Dam in 1963. Reduction of flooding after 1963 permitted widespread marsh development. Fluvial marshes exhibited low stability but high resilience, quickly redeveloping after scouring by high flows between 1983 and 1986. In 1991, 253 fluvial wet marshes (cattail/reed and horseweed/Bermudagrass) and 850 dry marshes (horsetail/willow) occupied 25.0 ha (1%) of the 363 km mainstream riparian corridor between Lees Ferry and Diamond Creek, Arizona. Fluvial marsh development and composition varied in relation to local and reach‐based geomorphology, and microsite gradients in inundation frequency and soil texture. Colorado River marsh density (number/km2) increased with distance downstream, and marshes were larger and more abundant in wide reaches. Wet marsh cattail/reed stands developed on silty loam soils in low velocity depositional environments that were inundated 54% of the days from 1986 to 1991, whereas dry horsetail/willow marshes occupied less frequently inundated sites with sandy soils. Mean marsh standing mass (641 g C/m2) was comparable with values from regulated alluvial river marshes, but litter retention appeared limited by flow variability in both regulated and unregulated fluvial marshes. We discuss implications of flow management on the four marsh assemblages, and the need for consensus on priorities for management of regulated fluvial wetlands.

Regulated river restoration through planned flooding involves trade-offs between aquatic and terrestrial components, between relict pre-dam and novel post-dam resources and processes, and between management of individual resources and ecosystem characteristics. We review the terrestrial (wetland and riparian) impacts of a 1274 m 3 /s test flood conducted by the U.S. Bureau of Reclamation in March/April 1996, which was designed to improve understanding of sediment transport and management downstream from Glen Canyon Dam in the Colorado River ecosystem. The test flood successfully restored sandbars throughout the river corridor and was timed to prevent direct impacts to species of concern. A total of 1275 endangered Kanab ambersnail (Oxyloma haydeni kanabensis) were translocated above the flood zone at Vaseys Paradise spring, and an estimated 10.7% of the total snail habitat and 7.7% of the total snail population were lost to the flood. The test flood scoured channel margin wetlands, including potential foraging habitats of endangered Southwestern Willow Flycatcher (Empidonax traillii extimus). It also buried ground-covering riparian vegetation under Ͼ1 m of fine sand but only slightly altered woody sandbar vegetation and some return-current channel marshes. Pre-flood control efforts and appropriate flood timing limited recruitment of four common nonnative perennial plant species. Slight impacts on ethnobotanical resources were detected Ͼ430 km downstream, but those plant assemblages recovered rapidly. Careful design of planned flood hydrograph shape and seasonal timing is required to mitigate terrestrial impacts during efforts to restore essential fluvial geomorphic and aquatic habitats in regulated river ecosystems.

The allotetraploids (2n = 24) Tragopogon mirus and T. miscellus have become textbook examples of recently and recurrently formed allopolyploids. Both species formed following the introduction of three diploids, T. dubius, T. porrifolius and T. pratensis (each with 2n = 12), from Europe into the Palouse region of eastern Washington and adjacent Idaho, USA, in the early 1900s. The parentage of both allotetraploids is well documented (T. mirus = T. dubius ¥ T. porrifolius; T. miscellus = T. dubius ¥ T. pratensis), and both allotetraploids have formed repeatedly in the past approximately 80 years in the Palouse. On a larger geographical scale, T. mirus has also been reported from Flagstaff, Arizona (AZ), and more recently from Oregon (OR). However, the populations from OR and AZ have not been previously analysed with molecular markers to test the hypothesis of separate origin (vs. long-distance dispersal). Here, we show that both the AZ and OR collections of T. mirus combine distinctive parental genotypes and are genetically differentiated from the T. mirus genotypes found in the Palouse. The OR sample of T. mirus has a genetically distinct T. dubius contribution that forms a clade in our analyses with a sample of what has been referred to as T. major (now considered a subspecies of T. dubius). Consistent with other naturally occurring T. mirus populations, plastid sequences indicate that T. porrifolius was the maternal parent for both the AZ and OR collections. Microsatellite data are also consistent with local formation of T. mirus from co-occurring populations of T. dubius and T. porrifolius in OR and AZ. As with sequence data, T. dubius from OR is distinct from other samples of T. dubius at microsatellite loci, contributing a unique signature to T. mirus from this location. It will be useful to include these additional geographical origins of T. mirus, particularly the more genetically distant sample from OR, in ongoing investigations of the genetic and genomic consequences of recent allopolyploidy.

No abstract