When: Saturday, May 4, 2024 from 9:30 a.m. -12:00 pm
Cost: $30
Location: emailed to participants.
Instructors: UC Cooperative Extension Stanislaus County Master Gardeners Roxanne Campbell, Rho Yare, and Sandy Mann.
Sign Up: Space is limited, register by paying online at https://ucanr.edu/succulents/2024
If you can't pay by credit card, we will accept cash or check if paid before May 1, 2024. Email aschellman@ucanr.edu or call (209) 525-6800 and ask for Anne to arrange to pay ahead.
This class does not accept walk-ins, payment must be made ahead of time.
- Author: Kathy Keatley Garvey
Assistant professor Laura "Melissa" Guzman of the University of Southern California (USC) will discuss "Using Occupancy Models to Infer Trends of Bee Biodiversity in North America" at the April 29th seminar hosted by the UC Davis Department of Entomology and Nematology.
Her seminar begins at 4:10 p.m. in 122 Briggs Hall and also will be on Zoom. The Zoom link:
https://ucdavis.zoom.us/j/9 5882849672
"Historical museum records provide potentially useful data for identifying drivers of temporal trends in species occupancy, however, because these records were not explicitly collected for this purpose, methodological developments are needed in order to enable robust inferences," Guzman writes in her abstract. "Occupancy-detection models, a relatively new and powerful suite of methods, are potentially useful here, because these models allow us to account for changes in collection effort through space and time. Applying such occupancy-detection models to historical museum records is not a straightforward process, as these models have strict data requirements that museum data usually do not meet."
"Here I will present a methodological road-map for using occupancy models to analyze historical museum records. I use simulated data-sets to identify how and when modeling decisions and patterns in data can bias inferences. I will focus primarily on the consequences of contrasting methodological approaches for dealing with species ranges and non-detections in both space and time. Finally, I will present an application of these methods to bees in North America and will present drivers of change for these species in the past 30 years."
Guzman says that the "overarching goal of my research is to develop statistical and computational methods to leverage large biodiversity datasets to learn about ecological processes. While we know that the distribution of some species is changing, it is actually very difficult to make reliable inferences as to which species are declining and by how much from the often messy and complex historical and spatial datasets that we have to work with — for example, historical museum records, where species occurrences are aggregated from studies with different sampling procedures."
"In order to address this gap," Guzman says, "my research focuses on determining if and how statistical models can be applied to historical records without yielding biased trends. In my research I also apply these statistical models to determine how the distribution of pollinators has changed through time, where museum records provide lots of information. I am also interested in determining which drivers (e.g. pesticide use, climate change, land use change, etc.) are causing the most decline of the most pollinator species."
"Another aspect of my research is to understand the processes that shape communities, for example, I have combined experiments and modelling to understand how the structure of body size in a community affects the stability of food webs. In more recent work, I used large-scale simulations and machine learning to identify the signal of metacommunity processes in ecological time series."
Guzman is a Gabilan assistant professor in USC's Department of Biological Sciences. She received two degrees from McGlll University: her bachelor's degree (2012) in biology and her master's degree (2013) in ecology and evolution. She obtained her Ph.D. at the University of British Columbia.
She recently co-authored a piece in the journal Ecology titled "A Data Set for Pollinator Diversity and their Interactions with Plants in the Pacific Northwest," published in November 2022.
The abstract:
"Pollinator populations have declined substantially in recent years. The resulting loss in pollination services has both ecological and economic consequences, including reductions in plant diversity and crop production and lower food security. Data sets that identify pollinators and their plant hosts are of the utmost importance for the light can shed on the main causes of pollinator declines. Here we present a data set that contains 67,954 individual pollinator records. The data were collected across the Pacific Northwest, primarily focused in British Columbia (Canada), with 182 individual sites over 11 years, between 2005 and 2017. This data set comprises multiple studies that aimed to collect information on pollinator abundance, diversity, and their interactions with plants. Overall, the data set includes 937 morphospecies (of which 482 were identified to the species level) of pollinators across 105 families, including data for bees, wasps, butterflies, moths, and flies. We also present information on the interactions of these species, with 473 species of plants. The data set is being released for noncommercial use only. Credits should be given to this paper (i.e., proper citation)."
Guzman won the American Society of Naturalists Young Investigator Award, 2022-2023, and the Canadian Society of Ecology and Evolution Early Career Award, 2022-2023.
For any technical Zoom issues, contact seminar coordinator Brian Johnson at brnjohnson@ucdavis.edu. The full list of spring seminars is here.
- Author: Luis Espino
Arthropods have not been very problematic in California in the past few years. However, do not let your guard down and let the bugs catch you unprepared. The tadpole shrimp is our key pest. Shrimp tend to be a problem in the same fields year after year because their eggs remain in the soil from one season to the next. Make sure to scout fields soon after seeding, maybe even before seeding, especially fields that take more than a few days to flood. Tadpole shrimp eggs hatch very soon after the field is flooded and the young shrimp grow quickly. Seeding into a field with shrimp present, even small shrimp, is asking for trouble. Small shrimp (about ½ an inch or less) can injure rice, just not as much as larger shrimp. Also, do not just rely on the muddiness of the water. When they are small, shrimp do not disturb the soil much, and therefore you might not see muddy water even though shrimp are present.
Another arthropod that can be problematic in California is the armyworm. Many fields had significant yield losses during the outbreak of 2015. We have not seen a similar outbreak since, but in some years worm numbers have been high. I have been monitoring armyworm moth populations with pheromone traps across the rice area since 2018. Last year we had the highest moth numbers we have ever seen but that did not translate into high worm numbers in the field. In fact, the worm pressure was very low. While the traps do not predict worm numbers, they can help us improve the timing of scouting. We know that we will see the highest worm numbers two weeks after the moth numbers peak. With Intrepid now fully registered for use in rice, we have a good tool that we can use to control armyworm populations if they get out of hand. You can sign up for my armyworm updates on the UC rice website.
The last pest that can be of concern is rice seed midge. The past three years we have seen some fields suffer stand reduction due to midge. This is a difficult pest to manage given its sporadic nature. Ian Grettenberger, UC Davis Extension Entomologist, has been doing insecticide trials for midge control. His work shows that pyrethroids are not very effective against midge, but at this point they are the only tool we have. Like tadpole shrimp, rice seed midge can be worse in fields that take a long time to flood. Also, late planted fields are at more at risk. Scout your field right at seeding and for the next few days, looking for the silken tubes rice seed midge form on the soil surface and inspect seed looking for injury. If there is enough injury to reduce the stand significantly, use an insecticide. A brief drain will also work; however, take into consideration any effects the drain may have in weed control and fertility.