The following videos were made to explain how to accurately monitor vegetation and its utilization. The target audience was those people that manage land for livestock production on a sustained yield basis. These videos are sequential in nature and should be viewed in order.
Ecologists continually strive to develop field measurement techniques that are fast, accurate and repeatable. Photography, from platforms, aircraft, and satellites have been used to monitor the status of vegetation on landscapes for many years. In the 1990’s, we coupled film and later, digital cameras with GPS loggers that allowed us to collect high resolution images that could be geographically registered to positions on the landscape. Images were not only positioned but also rotated and scaled so quantitative measures could be derived from the saved photos. This type of information is extremely valuable because it allows us “look back” capabilities. If we wish to examine the completed survey five years after it was completed for another parameter, such as the presence of a weedy species or the percent cover of a specific plant, we can use the photos for this purpose. The process of collecting geographically registered photographic images according to our protocol is called “digital charting”. This video introduces students to digital charting.
The next video explains why land has to be partitioned into ecological sites and how this is done. Partitioning is necessary because land parcels on the landscape are similar and can be managed using the same techniques. Uniform areas are much easier to sample for an accurate estimate of the mean with a relatively low standard deviation. These similar land units also respond to environmental fluctuations, such as drought or pluvial periods in a similar fashion and their production is similar. As would be expected, they often respond similarly to management. For this reason, we stratify the land surface into a series of similar units or ecological sites. This video provides an example of a sagebrush dominated landscape that has been subdivided into ecological sites.
Plant production and the management of forage plants is the foundation of the herder’s economy. Plants should be managed to maintain their health and vigor, only removing as much tissue as the plant can easily tolerate. Typically, several plant species constitute the bulk of forage provided to animals. In this video, we demonstrate the use of the quadrat and show how it can be clipped to provide a quantitative measure of the total aboveground phytomass on an ecological site. Measuring plant production is very time consuming and therefore expensive, so it is important that data collection is done as efficiently as possible. This video demonstrates the basic techniques of measuring plant production.
When animals graze plants and remove tissue there are impacts to the plant. Most plants have tolerance to grazing and can rebound quickly. Frequent or excessive defoliation can reduce a plants competitive ability which can lead to death. As you might imagine, different plant species have differing tolerances to defoliation and defoliation in different seasons can affect plants differently. It is therefore important that the level of utilization by animals is monitored and controlled. This video introduces several techniques that allow the measurement of plant utilization by animals.