Tag Archive | Phenology

Wisconsin’s Phenological Legacy

Sunset over a lake in winter

With the help of volunteer trail camera hosts, Snapshot Wisconsin is lucky to monitor over 2,000 cameras throughout the state. This people-powered data collection allows researchers to gain valuable insight into wildlife activity throughout the year. Along with the time-lapse photos that all Snapshot Wisconsin cameras are programmed to capture once per day, 365 days per year, the cameras also capture seasonal wildlife trends like increased animal activity, color-changing coats and the return or departure of migratory birds.

While Snapshot does not currently keep track of the firsts and lasts for all our cameras, each individual camera host can! This is a type of phenological record keeping. The USA National Phenology Network tracks the phenological events of “nature’s calendar,” keeping a record of the “firsts” and “lasts” that occur throughout a year and allowing scientists to establish a sense of how species respond to natural cues such as temperature and day length. Phenology is extremely accessible and both professional and citizen scientists can participate in creating phenological data sets.

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Wisconsin has a rich phenological record keeping history, one of the most well-known contributors being the Leopold family.

Aldo Leopold was the first chair of the Department of Forest and Wildlife Ecology at the University of Wisconsin-Madison. His work and writings have inspired countless environmentalists, conservationists, and nature-goers. Leopold’s phenology is famous; he took extensive notes and kept meticulous records. Leopold lived in Madison during the work week, but on the weekends he would go out to a shack on land that he and his family owned in Baraboo on the Wisconsin River. There he would rise early in the morning to observe and document the birds and plants that emerged that day. Almost 80 years later, ecologists recreated a soundscape of Leopold’s shack using the data that he took from this one particular spot.

An old-looking notebook page from Aldo Leopold's field notebook

A page in one of Aldo Leopold’s field notebooks from the 1940s – University of Wisconsin Archives

The audio was created using the ecological and species identification expertise of Professor Stan Temple of UW-Madison, as well as the audio knowledge of Chrys Bocast, a graduate student and acoustic ecologist at the Nelson Institute for Environmental Studies. The soundtrack transports the listener to a spring morning along the sandy shores of the Wisconsin River in the 1940s. This was the first time that today’s ecologists could experience what Leopold had decades earlier. It was also a way for the scientists to hear the differences in the acoustic landscape, not just see it on paper or graphs. Phenological records — records kept both then and now — allow scientists like Temple and Bocast to bridge the gaps between environmental past, present, and future.

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Data that are contributed through Snapshot cameras can inform our knowledge of who, what, where and when our favorite wildlife species are emerging, and what we can expect in the years to come based off of historical data. If you are interested in helping contribute to phenological record keeping, there are an overwhelming number of ways to get involved other than hosting a trail camera or classifying photos on Zooniverse. These resources can be found in the Nature’s Notebook section of the National Phenology Network website.

April Science Update: Time-lapse Photos

The Snapshot Wisconsin team is often asked why we accept data only from our Snapshot-specific cameras. While there are several reasons, the reason that was highlighted in the April 2019 newsletter was because Snapshot Wisconsin cameras are programmed to take a single photo at 10:40 a.m. each day.  Although 10:40 may seem like an arbitrary time, this corresponds to the approximate time that a NASA satellite flies over Wisconsin and collects aerial imagery. (More information on how NASA data and Snapshot data are complementary can be found in this blog post.)

Timelapse

An example of a motion-triggered photo and a time-lapse photo from the same site in Sawyer County, September 2017.

It may be difficult to recognize the value of a blank photo in wildlife research, but a year-long series of these photos allows us to examine something very important to wildlife: habitat condition. For each camera site, the time-lapse photos are loaded into the statistical software, “R,” where each pixel in the image is analyzed and an overall measure of greenness is summarized for the entire photo. That measure, called the Green Chromatic Coordinate, can be used to identify different “phenophases,” or significant stages in the yearly cycle of a location’s plants and animals. These stages can be delineated on a graph, called a phenoplot, where a fitted curve reveals the transition day-by-day. The 2018 phenoplot for one Snapshot Wisconsin camera site is seen below.

PhenoPlot

 

PhenoPhases

Time-lapse photos from the corresponding phenophases as identified by the phenoplot above.

In 2018, 45 camera sites had a complete set of 365 time-lapse photos, but we expect many more sites to be included in the 2019 analyses. The relatively small sample size for 2018 is due in part to many counties not being opened for applications until partway through the year, but also because time-lapse data are rendered unusable if the date and time are not set properly on the camera. This may happen when the operator accidentally sets the time on the 12-hour clock instead of the 24-hour clock, or if the hardware malfunctions and resets the date and time to manufacturer settings—this is why we ask our volunteers to verify the camera’s date and time settings before leaving the site each time they perform a camera check.

The information derived from these analyses will be integrated into wildlife models. For example, the objective of one ongoing DNR research project is to understand linkages between deer body condition and habitat, which includes what’s available to deer as forest cover and food resources, as well as weather-related factors, such as winter severity or timing of spring greenup. The project currently uses weather data collected across the state to estimate snow depth, temperature, and winter severity, and creates maps based off this information.

Snapshot’s time-lapse cameras offer a wealth of seasonal information regarding type of forest cover and food sources, as well as weather-related information. In the future, phenological data obtained from Snapshot cameras could be used to create “greenup maps” that provide estimates of where and when greenup is occurring, and potentially test that information as a means of better understanding how environmental factors affect deer health, such as whether an early spring greenup improved deer body condition the next fall.