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Cheatgrass (Bromus tectorum L.) has come to dominate millions of hectares of rangeland in the Intermountain western United States. Previous studies have hypothesized that one mechanism conferring a competitive advantage to this species is the ability to germinate rapidly at low temperatures in the fall, winter and spring and, therefore, initiate growth and establishment more rapidly than more desirable perennial bunchgrass species. In this experiment, we developed thermal-germination-response models for multiple seedlots of cheatgrass and five perennial grass species. We conducted sensitivity analysis on potential-cumulative-germination response to a 38-year simulation of field-variable conditions of seedbed temperature...
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These data were compiled as part of a field and growth chamber study of the establishment of Salsola tragus (Russian thistle), an invasive non-native annual plant in North America. Field work was conducted at Petrified Forest National Park, Arizona in 2015 and 2016 and the growth chamber study was conducted in 2016. The data represent field measurements of Salsola germination and growth (cover) and sediment movement at two field sites, one a stabilized sand sheet (SS) and the other on the ridge of a sand dune (SD). The data also represent a growth chamber assessment of the soil and litter seed bank from representative samples take at the two field sites.
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This dataset provides information on plant sexual reproduction of a clonally-spreading perennial species, Spartina alterniflora. We investigated flowering phenology, potential seed and seedling production, and flower damage in reference and restored sites in southeastern Louisiana. Additional covariates of elevation and soil parameters were used to investigate underlying mechanisms of differences.
Bromus tectorum is a dominant winter annual weed in cold deserts of western North America. We followed patterns of seed carry-over and abundance of the pathogen Pyrenophora semeniperda over 5 years at B. tectorum-dominated shadscale (Atriplex confertifolia) and sagebrush (Artemisia tridentata) sites in southern Idaho. We hypothesised that more seeds could potentially carry over at the drier shadscale site because of minimal autumn precipitation, but that P. semeniperda, a pathogen that primarily kills dormant seeds, would have more impact at the drier site, where a higher density of dormant seeds would likely be present in the early spring seedbank. Successful first-year seed carry-over was higher in years with...
Winterfat (Ceratoides lanata (Pursh) J.T. Howell, syn. Eurotia lanata (Pursh) Moq., syn. Krascheninnikovia lanata Gueldenstaedt) seeds possess an after-ripening requirement to break dormancy. Germination responses of winterfat seeds to ethanol, gibberellic acid (GA3), citric acid and sodium nitrate (NaNO3) were tested in the laboratory to determine their ability to break dormancy. Ethanol, GA3 and citric acid promoted, while NaNO3 inhibited germination. Ethanol promoted fast and synchronous germination. Promotion of germination by GA3 or citric acid was weak during the test period. Citric acid damaged the radicles of seedlings. Soaking winterfat seeds in 600 to 1,000 mM ethanol for 4 to 8 hours is recommended, as...
Impacts of long-term climate shifts on the dynamics of intact communities within species ranges are not well understood. Here, we show that warming and drying of the Southwestern United States over the last 25 years has corresponded to a shift in the species composition of Sonoran Desert winter annuals, paradoxically favoring species that germinate and grow best in cold temperatures. Winter rains have been arriving later in the season, during December rather than October, leading to the unexpected result that plants are germinating under colder temperatures, shifting community composition to favor slow growing, water-use efficient, cold-adapted species. Our results demonstrate how detailed ecophysiological knowledge...
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Data includes seed germination experiments observations from seeds collected during the fall of 2018 and 2020 at Bitter Lake National Wildlife Refuge, near Roswell, New Mexico. Seeds of Cirsium wrightii, Agalinis calycina, and Helianthus paradoxus were collected by manually clipping seed heads from plants across the wetland management units. Seeds were placed in brown paper bags and transported to the lab. In the lab, seeds from 2018 were immediately used for experiments by placing them in an incubator using petri dishes. Seeds collected in 2020 received cold stratification and salinity treatments. Following cold stratification, seeds were placed in the incubator and received salinity treatments. Seeds were monitored...
In the shortgrass steppe region of North America there is a controversy about the ability of the dominant species to recruit from seedlings. The prevailing view is that Bouteloua gracilis is incapable of recruitment from seedlings in areas receiving <380 mm of annual precipitation. A common explanation for this situation is that environmental conditions permitting seedling establishment are infrequent. To assess the frequency of environmental conditions appropriate for the recruitment of B. gracilis we used a soil water simulation model and long-term climatic data in conjunction with detailed information about the ecophysiological requirements for seed germination and growth of seminal and adventitious roots. We...
Millions of acres of rangeland in the western United States are now dominated by introduced annual weeds such as cheatgrass (Bromus tectorum L.). The ability to germinate rapidly at low temperatures has been proposed as one of many mechanisms that confer a competitive advantage to this species. Previous studies of this phenomenon, however, have been limited to relatively simple comparisons of total germinability and germination rate under selected constant-temperature treatments. In this study, we germinated seeds of cheatgrass and two native perennial bunchgrass species, bluebunch wheatgrass [Pseudoroegneria spicata (Pursh) Löve] and big squirreltail [Elymus multisetus (J.G. Smith) M.E. Jones], over the temperature...
    map background search result map search result map Russian-thistle field and seed bank data at Petrified Forest National Park, Arizona, 2015-2016 Salt marsh phenology and sexual reproductive characteristics at reference and restored sites in Louisiana, USA (2016) Seed germination requirements and seed responses to salinity for three rare wetland plants of spring-fed arid systems at Bitter Lake National Wildlife Refuge near Roswell, New Mexico 2018-2020 Seed germination requirements and seed responses to salinity for three rare wetland plants of spring-fed arid systems at Bitter Lake National Wildlife Refuge near Roswell, New Mexico 2018-2020 Salt marsh phenology and sexual reproductive characteristics at reference and restored sites in Louisiana, USA (2016) Russian-thistle field and seed bank data at Petrified Forest National Park, Arizona, 2015-2016