New views!
by Dr. Chad Zirbel, postdoc on the bison research project
You may have recently noticed some new cameras showing up that are pointed at strange metal cages. These cameras are a part of the bison experiment at Cedar Creek. In this experiment, we are trying to understand if and how bison can help maintain and restore oak savannas.
Oak savannas are ecosystems that contain an understory of grasses and wildflowers with a sparse tree canopy dominated by Oak trees (Quercus spp.). It is estimated that, at one time, there were approximately 50 million acres of oak savanna stretching across the midwestern United States. Many of these oak savannas were converted to homesteads, tilled for agriculture, or became fire suppressed allowing non-oak trees to grow, turning the savannas into closed-canopy forests. Today, less than 1% of the savanna remains, making it a highly threatened ecosystem. Many plants and animals, such as Red-headed woodpeckers (Melanerpes erythrocephalus) and Purple Milkweed (Asclepias purpurascens), specialize on the open structure of oak savanna ecosystems. Sadly, with the loss of savanna, many of these species are now declining. Although efforts to restore oak savanna have been largely successful, recruitment of oak trees is often insufficient. Without new oak seedlings, our remaining savannas will eventually lose their oaks and turn into open grasslands, furthering the loss of these savanna systems.
While fire was historically a natural part of oak savanna systems and necessary for maintaining their open structures, intense fires often kill young oak seedlings. While adult oak trees can survive fires, most young trees cannot survive an intense fire until they reach a particular size. Fires also promote dominant grasses in oak savanna, which, in turn, causes more intense fires. In addition, dominant grasses compete with oak seedlings for limited resources like light, water and nutrients. This competition may slow seedling growth, increasing the amount of time it takes for seedlings to grow large enough to survive an intense fire.
Historically, large grazing herbivores (like bison) were important in many savanna ecosystems. Bison primarily consume dominant grasses in these systems, which may help to reduce competition and decrease fire intensity, allowing oak seedlings to grow. Unfortunately, bison went locally extinct almost 200 years ago, and the benefits they may have provided to oak savannas were lost.
To better understand the effects of bison on savanna ecosystems, we release a herd of bison every spring at Cedar Creek. These bison graze a 210-acre area of the savanna for the entire growing season. Within these 210 acres, there are 14 pairs of plots. In each pair, there is one plot that is open, while the other is enclosed—the enclosed plots are the large metal cages you see on camera. The “cage” prevents bison from grazing in that plot, while the plot next to it, marked by metal conduit, allows bison grazing.
In each of the two plots (one fenced off and one open), there are 20 oak trees planted. Every summer we measure the growth and survival of these oak seedlings to understand the impact of bison grazing on oak trees. We also collect data on them after the spring prescribed burning season.
We know the primary way bison might be able to help oak trees is by eating the dominant grasses. We can measure how much grass the bison eat each year, but we also want to know more about how the bison interact with our plots and the savanna. How much time the bison spend grazing at each of the plots? How frequently do they visit different parts of the savanna? Does this change from the spring to the fall? The data we get from trail cameras and classifications by volunteers allows us to answer these questions and more. In the updated version of the Biodiversity Detective workflow, you'll see a new question when you choose bison as the animal in the images: if you marked 'eating' as a behavior taking place, how many bison are eating?
To best observe the bison, we have placed one camera at each of the 14 plot pairs. Like the Eyes on the Wild grid cameras, our bison cameras generally face north: unless there wasn’t a good place to put a camera or the view of the plots is blocked from that direction. The cameras are 25 meters from each plot so that both plots are in the frame and we have a similar chance of a bison triggering the camera at each plot. You may also notice that the cameras are a little higher off the ground than you may have seen in the past. The bison project cameras are 5 feet high, while the Eyes on the Wild grid cameras are only 3 feet high. This is because our main goal is capture pictures of bison (although we love seeing other species pop in, too - like the doe and fawns in the image below!) and we want to make sure the camera won’t be blocked by bison that might walk directly in front of it. By having the cameras higher up, we can get a better view that allows us to get a more accurate count of how many bison are near each plot at any given time.
Enjoy the new bison photos and some new views of the oak savannas at Cedar Creek. You can learn more about the bison project by visiting: https://www.cedarcreek.umn.edu/conservation/bison
Like the overall Eyes on the Wild project, funding for our bison research is provided by the Minnesota Environment and Natural Resources Trust Fund as recommended by the Legislative‐Citizen Commission on Minnesota Resources (LCCMR). The Trust Fund is a permanent fund constitutionally established by the citizens of Minnesota to assist in the protection, conservation, preservation, and enhancement of the state’s air, water, land, fish, wildlife, and other natural resources. Currently 40% of net Minnesota State Lottery proceeds are dedicated to growing the Trust Fund and ensuring future benefits for Minnesota’s environment and natural resources.
All photos and video on this post were taken at the reserve by Cedar Creek staff and researchers and are used with permission.
You may have recently noticed some new cameras showing up that are pointed at strange metal cages. These cameras are a part of the bison experiment at Cedar Creek. In this experiment, we are trying to understand if and how bison can help maintain and restore oak savannas.
Oak savannas are ecosystems that contain an understory of grasses and wildflowers with a sparse tree canopy dominated by Oak trees (Quercus spp.). It is estimated that, at one time, there were approximately 50 million acres of oak savanna stretching across the midwestern United States. Many of these oak savannas were converted to homesteads, tilled for agriculture, or became fire suppressed allowing non-oak trees to grow, turning the savannas into closed-canopy forests. Today, less than 1% of the savanna remains, making it a highly threatened ecosystem. Many plants and animals, such as Red-headed woodpeckers (Melanerpes erythrocephalus) and Purple Milkweed (Asclepias purpurascens), specialize on the open structure of oak savanna ecosystems. Sadly, with the loss of savanna, many of these species are now declining. Although efforts to restore oak savanna have been largely successful, recruitment of oak trees is often insufficient. Without new oak seedlings, our remaining savannas will eventually lose their oaks and turn into open grasslands, furthering the loss of these savanna systems.
While fire was historically a natural part of oak savanna systems and necessary for maintaining their open structures, intense fires often kill young oak seedlings. While adult oak trees can survive fires, most young trees cannot survive an intense fire until they reach a particular size. Fires also promote dominant grasses in oak savanna, which, in turn, causes more intense fires. In addition, dominant grasses compete with oak seedlings for limited resources like light, water and nutrients. This competition may slow seedling growth, increasing the amount of time it takes for seedlings to grow large enough to survive an intense fire.
Historically, large grazing herbivores (like bison) were important in many savanna ecosystems. Bison primarily consume dominant grasses in these systems, which may help to reduce competition and decrease fire intensity, allowing oak seedlings to grow. Unfortunately, bison went locally extinct almost 200 years ago, and the benefits they may have provided to oak savannas were lost.
To better understand the effects of bison on savanna ecosystems, we release a herd of bison every spring at Cedar Creek. These bison graze a 210-acre area of the savanna for the entire growing season. Within these 210 acres, there are 14 pairs of plots. In each pair, there is one plot that is open, while the other is enclosed—the enclosed plots are the large metal cages you see on camera. The “cage” prevents bison from grazing in that plot, while the plot next to it, marked by metal conduit, allows bison grazing.
In each of the two plots (one fenced off and one open), there are 20 oak trees planted. Every summer we measure the growth and survival of these oak seedlings to understand the impact of bison grazing on oak trees. We also collect data on them after the spring prescribed burning season.
We know the primary way bison might be able to help oak trees is by eating the dominant grasses. We can measure how much grass the bison eat each year, but we also want to know more about how the bison interact with our plots and the savanna. How much time the bison spend grazing at each of the plots? How frequently do they visit different parts of the savanna? Does this change from the spring to the fall? The data we get from trail cameras and classifications by volunteers allows us to answer these questions and more. In the updated version of the Biodiversity Detective workflow, you'll see a new question when you choose bison as the animal in the images: if you marked 'eating' as a behavior taking place, how many bison are eating?
To best observe the bison, we have placed one camera at each of the 14 plot pairs. Like the Eyes on the Wild grid cameras, our bison cameras generally face north: unless there wasn’t a good place to put a camera or the view of the plots is blocked from that direction. The cameras are 25 meters from each plot so that both plots are in the frame and we have a similar chance of a bison triggering the camera at each plot. You may also notice that the cameras are a little higher off the ground than you may have seen in the past. The bison project cameras are 5 feet high, while the Eyes on the Wild grid cameras are only 3 feet high. This is because our main goal is capture pictures of bison (although we love seeing other species pop in, too - like the doe and fawns in the image below!) and we want to make sure the camera won’t be blocked by bison that might walk directly in front of it. By having the cameras higher up, we can get a better view that allows us to get a more accurate count of how many bison are near each plot at any given time.
Enjoy the new bison photos and some new views of the oak savannas at Cedar Creek. You can learn more about the bison project by visiting: https://www.cedarcreek.umn.edu/conservation/bison
Like the overall Eyes on the Wild project, funding for our bison research is provided by the Minnesota Environment and Natural Resources Trust Fund as recommended by the Legislative‐Citizen Commission on Minnesota Resources (LCCMR). The Trust Fund is a permanent fund constitutionally established by the citizens of Minnesota to assist in the protection, conservation, preservation, and enhancement of the state’s air, water, land, fish, wildlife, and other natural resources. Currently 40% of net Minnesota State Lottery proceeds are dedicated to growing the Trust Fund and ensuring future benefits for Minnesota’s environment and natural resources.
All photos and video on this post were taken at the reserve by Cedar Creek staff and researchers and are used with permission.
This is so awesome that the protection,preservation,and conservation of wild life and Mother Nature are making such a diffferance.
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