Wednesday, August 24, 2011

Intensive Grazing Study

The further I've gone west (from Massachusetts), the opportunity and level of experience has greatly increased. As a Biological Science Technician with the USFWS, I had the opportunity to volunteer for many events and projects that interested me. In preperation to lead the Native Prairie Adaptive Management project on Arrowwood National Wildlife Refuge, I was required to travel down to the small town of Streeter ND to participate in a vegetation identification workshop guided by Bob Patterson of the North Dakota State University Research Extension Center. On our way out into the field, Bob was kind enough to catch me up on his grazing study that has been going on for some 20 years. Weeks later, I was able to be contracted in to help gather data.

The study involves using two separate half-meter sq. plots - one "in" plot and two "out" plots per unit. The in plot was placed in an exclosure that keeps cattle from grazing it whereas the out plots were randomely placed in the grazed portion.

The protocol was designed to measure biomass of shrubs, forbs, and grasses.

This was my plot after picking the shrub layer and placing the contents into an individual paper bag. All species were identified and written on each bag for species richness data.

After all layers were picked and separated, this is what a plot looks like (left). All plants were harvested from the root collar up. An "in" plot has a barrier to deter cattle from grazing it (right).

Over all, the study was very interesting. I've seen deer exclosures throughout the Vinton Furnace State Experimental Forest and the large contrast between foraged and unforaged woodlots. This study had a very similar result throughout ND range. My passion is vegetation but I always like to study flora and fauna together. Studies like these really help to manage for both.


  1. Well Ive always heard that grazing helps land but Cattle are not native to this land and Im sure they spread a lot of non native species interesting to know the results of your test patches.

  2. Hey Sondra! As you know, during pre-settlement, bison roamed freely and grazed the great plains states. So, grazing is a natural mechanism of healthy prairies. Cattle are indeed non native but the animals that have moved the most non native plants around are humans, unfortunately.

    At the National Wildlife Refuge I worked at, they would alternate bison and cattle throughout management units to mimic what bison did hundreds of years ago. They both help control invasive like smooth brome and kentucky bluegrass, particularly in addition to other management practices like burning or chemical application. Also, both have similar digestive systems and produce a natural fertilizer for the seed they eat as they move through them., which can also be important to some prairie systems.

    If the refuge had it's way, I'm sure they would use more bison than cattle but cattle ranchers are so abundant in ND. That's what makes this such an interesting study - Cattle operations will always go on in ND. This study investigates the positives and negatives of grazing, which could be used to make recommendations to cattle ranchers in the future. It could help private land owners make better choices towards improving habitat and their land.