Southwest Season Tracker campaign
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Greetings!
After four years of data collection, the
Southwest Season Trackers campaign
has come to a close. The observations you collected are being used by researchers at the
Jornada Experimental Range
to verify predicted dates of start and end of the growing season. This is part of an ongoing study of plant phenology that allow researchers to create better models to predict leafing, flowering, and fruiting in Southwest species.
This will help us better understand when to harvest seeds and fruits of native plants, know when to apply herbicides to unwanted shrubs and reestablish grasslands, and predict the onset and peak in allergy season.
We greatly appreciate your participation over the last four years. You are welcome to continue observing your Southwest Season Trackers species in the future. The data that you collect and submit to the National Phenology Dababase offer a wealth of knowledge for researchers to explore. Thank you for all of your efforts!
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What you reported on Southwest shrubs and grasses
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Observers reported on southwest shrubs and grasses at
125 sites
over the last four years.
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Sites reporting on southwest shrubs and grasses in 2019. Colors correspond to species names across the top; darker colors indicate more observations made for that site. Green outlines indicate more than one species observed.
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Between LPP members and individual participants, we had
435 individual observers
submit data. 18 observers submitted data in all four years, 32 more submitted data in three years, and another 70 submit data in two years. Thank you for your efforts!
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The most commonly observed species in this campaign were creosote bush with over 63,000 observations and honey mesquite with 42,789 observations.
Over the last four years, you submitted observations on 155 creosote bushes in California, Arizona, and New Mexico.
This year, you reported young leaves throughout the year, with a decrease in the proportion of plants with young leaves from May to July. You reported a peak flowers or flower buds in April, and a peak in fruits from May to July.
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If we look at the pattern in four years of your data, we can see that creosote bush generally had open flowers in the spring between March and June, with a smaller flowering period from July to September. The exception is 2018, when observers also reported a peak in open flowers in early December. Perhaps this was due to some late fall rain?
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You reported ripe fruits throughout the year, with a higher proportion of individual creosote with ripe fruits in July.
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Over the last four years, you reported on 87 honey mesquite trees in California, Nevada, Arizona, and New Mexico.
This year, you reported a peak in young leaves and flowers for honey mesquite starting in March through June. You reported multiple peaks in fruits for honey mesquite, with the largest peaks from June to July and again in early September.
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If we look at the pattern in four years of your data, we see that generally, open flowers in honey mesquite peaked between April and June. In 2016, some observers reported early flowering in March, and some observers in 2017 reported late flowering in July.
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The pattern in ripe fruits for honey mesquite is less consistent. A variety of birds, rodents, and even livestock take advantage of this food source at different times of the year. There seems to be a peak in ripe fruits from July to August in most years, with other periods of fruits in different seasons depending on the year.
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Soaptree yucca was another commonly observed species, with 16,215 observations made on 72 individuals over the past four years in Arizona and New Mexico. You reported open flowers for yucca beginning in April in most years, with a peak in June one year and in July in another.
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A question to ponder...
In our last message, we asked why you think soaptree yuccas have a limited flowering and fruiting window, while other species like creosote bush and honey mesquite have more flexible flowering and fruiting times?
Like many yucca, soaptree yuccas have a special relationship with moths. The yucca moth pollinates the flowers and the month larvae feed exclusively on the developing fruit of the yucca. You can read more about the relationship between another species, soapweed yucca, and its moth on this
Cool Green Science blog post
.
These observations you so diligently collected represent a significant contribution to understanding the start and end of the season for these important dryland plant species. Researchers at the Jornada Experimental Range will use your data in two ways. First, they are an independent source of data to check the performance of their models of the transitions between life cycle stages. Second, your data are being used to evaluate new models that incorporate the water that is available to plants, which is an important driver of plant productivity in places where water is limited.
We will share outcomes as they emerge! Thank you for your steadfast and tenacious efforts over the course of this campaign.
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Did you earn your Southwest Season Tracker badge? See it on your
Observation Deck
.
Thank you for your contributions to this important project!
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Contact
Erin Posthumus
erin@usanpn.org
520-621-1670
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