CHADRON – Anthony Perlinski, assistant professor in the applied sciences department, spoke about using scales of time and space to study and manage ecosystems during his Graves Lecture Tuesday night at Chadron State College.
He showed a slide documenting stages of vegetation recovery on the Santa Rita experimental range near Tucson, Arizona, from nearly bare ground in 1902 to a mesquite shrubland in 2003. He said this example demonstrates hierarchal theory or ecosystem processes that change over space and time.
“If we don’t think about these factors, we have a tendency to misinterpret things. We have to understand where we’re at spatially and temporally. We have to understand what scale we are looking at if we are going to understand the processes that are important,” Perlinski said.
Perlinski also discussed “site” as a common term used by range management professionals over the past several decades to refer to a certain portion of land. However, ecosystem processes don’t tend to match property boundaries or state boundaries, leading to disputes over water and other natural resources.
Currently, “ecological site” is the accepted term to describe a distinctive kind of land with types and amounts of vegetation different from those on other kinds of lands. He shared an aerial map of Chadron State College showing five ecological sites on campus.
Additionally, Perlinski described alternate stable plant communities as the basic spatial unit in range management. He said an ecosystem can be represented by a model of a ball rolling back and forth between two high points. A catastrophic wildfire, invasive species or drought could move an ecosystem over a threshold into a new kind of community like a ball rolling into a different trough. Likewise, corrective actions or adequate rainfall could cause the area to return to its original status.
The broad array of factors influencing ecological sites include climate, topography, plants, grazing animals and soils.
“If you have the same suite of factors, you’re going to end up with the same ecological site, repeatable across the landscape and this helps us make range management decisions,” Perlinski said.
Since nearly 70 percent of Earth’s terrestrial systems are rangelands, it is key that these areas are managed appropriately. Perlinski said range management has the potential to make a huge impact on large scale issues such as carbon storage and global warming.
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