Phenology of seed maturation in babysbreath (Gypsophila paniculata) in northwest Michigan, USA, and its relation to glyphosate efficacy

AbstractBabysbreath or perennial babysbreath (Gypsophila paniculata L.) is an aggressive invasive plant in large parts of southern Canada and the northern and western United States. It reproduces and disperses by seed, so the phenology of seed maturation is important in designing management programs. The present study provides the first quantitative assessment of G. paniculata seed-maturation phenology in a field population, as well as the first quantitative assessment of how the efficacy of herbicide treatment in preventing production of germinable seeds depends on the timing of treatment in relation to this phenology. Seeds were collected from untreated plants on five dates during July and August in both 2016 and 2017 and tested for germinability. Percent germination increased from 20% to 81% between July 22 and 28 and exceeded 90% by August 4, 2016. The seed-maturation phenology in 2017 was similar but delayed by about 4 d. On a growing degree-day scale, seed-maturation phenologies for the 2 yr were nearly identical. We also tested germinability of seeds from plants sprayed with glyphosate (23.4 ml ae L−1) on July 11, 18, and 25, 2016 (one date per plant). Percent germination increased from 0% to 13% to 20% over successive treatment dates, highlighting the importance of completing treatment early in the growing season.

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Using Expert Knowledge to Satisfy Data Needs: Mapping Invasive Plant Distributions in the Western United States

Western North American Naturalist ◽

10.3398/064.071.0314 ◽

2011 ◽

Vol 71 (3) ◽

pp. 302-315 ◽

Cited By ~ 15

Author(s):

Bethany A. Bradley ◽

David C. Marvin

Keyword(s):

United States ◽

Invasive Plant ◽

Expert Knowledge ◽

Western United States ◽

Plant Distributions

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Comparative Quality and Trend of Remotely Sensed Phenology and Productivity Metrics across the Western United States

Remote Sensing ◽

10.3390/rs12162538 ◽

2020 ◽

Vol 12 (16) ◽

pp. 2538

Author(s):

Ethan E. Berman ◽

Tabitha A. Graves ◽

Nate L. Mikle ◽

Jerod A. Merkle ◽

Aaron N. Johnston ◽

...

Keyword(s):

United States ◽

Remote Sensing ◽

Growing Season ◽

Remotely Sensed ◽

Deciduous Forests ◽

Western United States ◽

Instantaneous Rate ◽

Near Surface ◽

Changes Over Time ◽

Over Time

Vegetation phenology and productivity play a crucial role in surface energy balance, plant and animal distribution, and animal movement and habitat use and can be measured with remote sensing metrics including start of season (SOS), peak instantaneous rate of green-up date (PIRGd), peak of season (POS), end of season (EOS), and integrated vegetation indices. However, for most metrics, we do not yet understand the agreement of remotely sensed data products with near-surface observations. We also need summaries of changes over time, spatial distribution, variability, and consistency in remote sensing dataset metrics for vegetation timing and quality. We compare metrics from 10 leading remote sensing datasets against a network of PhenoCam near-surface cameras throughout the western United States from 2002 to 2014. Most phenology metrics representing a date (SOS, PIRGd, POS, and EOS), rather than a duration (length of spring, length of growing season), better agreed with near-surface metrics but results varied by dataset, metric, and land cover, with absolute value of mean bias ranging from 0.38 (PIRGd) to 37.92 days (EOS). Datasets had higher agreement with PhenoCam metrics in shrublands, grasslands, and deciduous forests than in evergreen forests. Phenology metrics had higher agreement than productivity metrics, aside from a few datasets in deciduous forests. Using two datasets covering the period 1982–2016 that best agreed with PhenoCam metrics, we analyzed changes over time to growing seasons. Both datasets exhibited substantial spatial heterogeneity in the direction of phenology trends. Variability of metrics increased over time in some areas, particularly in the Southwest. Approximately 60% of pixels had consistent trend direction between datasets for SOS, POS, and EOS, with the direction varying by location. In all ecoregions except Mediterranean California, EOS has become later. This study comprehensively compares remote sensing datasets across multiple growing season metrics and discusses considerations for applied users to inform their data choices.

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Writing Time in Metaphors

10.3366/edinburgh/9781474423939.003.0004 ◽

2018 ◽

Author(s):

Jennifer J. Smith

Keyword(s):

United States ◽

The United States ◽

Western United States ◽

Entire System ◽

Language And Culture ◽

Space Race ◽

Do So

Coherence of place often exists alongside irregularities in time in cycles, and chapter three turns to cycles linked by temporal markers. Ray Bradbury’s The Martian Chronicles (1950) follows a linear chronology and describes the exploration, conquest, and repopulation of Mars by humans. Conversely, Louise Erdrich’s Love Medicine (1984) jumps back and forth across time to narrate the lives of interconnected families in the western United States. Bradbury’s cycle invokes a confluence of historical forces—time as value-laden, work as a calling, and travel as necessitating standardized time—and contextualizes them in relation to anxieties about the space race. Erdrich’s cycle invokes broader, oppositional conceptions of time—as recursive and arbitrary and as causal and meaningful—to depict time as implicated in an entire system of measurement that made possible the destruction and exploitation of the Chippewa people. Both volumes understand the United States to be preoccupied with imperialist impulses. Even as they critique such projects, they also point to the tenacity with which individuals encounter these systems, and they do so by creating “interstitial temporalities,” which allow them to navigate time at the crossroads of language and culture.

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