Department
Biological Sciences
Advisor
Dr. Sara A. Wyse
Location
Bethel University
Document Type
Poster
Keywords:
goat grazing, buckthorn, invasive plants
Abstract
In years past, high levels of biodiversity and herds of roaming grazing animals maintained a delicate balance between species of plants. More recently due to globalization and deforestation foreign species like Rhamnus cathartica have been able to grow unchecked. Our study uses long term data from periodically goat-grazed areas near Bethel University, MN to evaluate the effectiveness of goat grazing to manage invasive plant species. Random one square meter quadrats were established in 2018 (n=70) to compare the differences in R. cathartica stem density between three height categories (0-30 cm, 30-150 cm, >150 cm), as well as other plant species present in each plot. These data were consolidated into a large database and analyzed. Since 2018, R. cathartica stems of length 30 cm-150 cm in grazed plots show a marked decrease in density when compared with ungrazed control plots. Additionally, stems of length greater than 150 cm show a downward trend in grazed plots over time, suggesting a decrease in new large bush growth in grazed plots. These findings suggest that goat grazing is an effective and efficient method to manage the overgrowth of single species like R. cathartica, and prevent overcrowding of endemic species. Further research will investigate different patterns of grazing over time and the impact of other plant species on R. cathartica abundance.
Recommended Citation
Stark, Isaac W., "Assessing the long-term impact of goat grazing on the abundance of Rhamnus cathartica" (2025). Science Symposium. 6.
https://spark.bethel.edu/science_symposium/spring2025/schedule2025/6
Included in
Assessing the long-term impact of goat grazing on the abundance of Rhamnus cathartica
Bethel University
In years past, high levels of biodiversity and herds of roaming grazing animals maintained a delicate balance between species of plants. More recently due to globalization and deforestation foreign species like Rhamnus cathartica have been able to grow unchecked. Our study uses long term data from periodically goat-grazed areas near Bethel University, MN to evaluate the effectiveness of goat grazing to manage invasive plant species. Random one square meter quadrats were established in 2018 (n=70) to compare the differences in R. cathartica stem density between three height categories (0-30 cm, 30-150 cm, >150 cm), as well as other plant species present in each plot. These data were consolidated into a large database and analyzed. Since 2018, R. cathartica stems of length 30 cm-150 cm in grazed plots show a marked decrease in density when compared with ungrazed control plots. Additionally, stems of length greater than 150 cm show a downward trend in grazed plots over time, suggesting a decrease in new large bush growth in grazed plots. These findings suggest that goat grazing is an effective and efficient method to manage the overgrowth of single species like R. cathartica, and prevent overcrowding of endemic species. Further research will investigate different patterns of grazing over time and the impact of other plant species on R. cathartica abundance.