Tag Archives: platte river

A Guide to Patch-Burn Grazing for Biological Diversity

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Patch-burn grazing is getting a lot of attention from a wide variety of audiences these days.  The management system has generated substantial enthusiasm among some people – particularly those interested in improving habitat for prairie wildlife species.  It has also generated substantial skepticism among others – particularly those concerned about potential negative impacts of grazing in eastern tallgrass prairies.

To date, the majority of research on and demonstration of patch-burn grazing has been oriented toward influencing agricultural grassland management because of the system’s potential to improve wildlife habitat at those sites.  Research has largely shown that farmers and ranchers can reap the habitat benefits of patch-burn grazing without compromising current stocking rates or livestock performance.  Because wider adoption of patch-burn grazing techniques on private lands could have tremendous positive impacts on prairie wildlife populations, those research results are exciting, and the continuation of work toward that objective is very appropriate and important.

However, the emphasis on developing and testing patch-burn grazing as an agricultural tool has also somewhat limited our ability to evaluate the system’s impacts (current and potential) on biological diversity.  Variables such as stocking rates, timing and intensity of grazing, fire season and frequency, and others tend to be defined such that they are compatible with local grazing systems and cultures.  Again, this is very appropriate, but it also narrows the range of possible modifications to the basic patch-burn grazing model that are being tested.

In contrast to research projects oriented toward balancing agricultural production with wildlife habitat, our work with patch-burn grazing in the Platte River Prairies of Nebraska is targeted only at building and sustaining biological diversity.  Our stocking rates, fire frequency, and other variables are all primarily designed to favor plant diversity.  Because few others are experimenting with patch-burn grazing from the same standpoint, we have tried to gather as much data as we can about the impacts of our various patch-burn grazing modifications – especially related to impacts on plant species and plant communities.  We’re taking the approach that if we can learn how to optimize management for plant diversity and overall biological diversity, we can then help translate and modify those methods to fit the specific needs of private landowners, public land managers, and others.

A burned patch in restored prairie along the Platte River in Nebraska. Cattle are concentrating their grazing in this area, but the light stocking rate employed means that while many grasses are being grazed, most forbs are not. In this case, ungrazed forbs include opportunistic plants such as black-eyed susan and hoary vervain, but also compass plant and Canada milkvetch, which are often viewed as negatively affected by cattle grazing.

This week I attempted to capture what we’ve learned about patch-burn grazing to this point and incorporate it into a single document.  We certainly don’t have all the answers, and the document should not be read as a prescription for precisely how to employ patch-burn grazing.  Rather, it is a description of the kinds of things we’re trying on our sites and the results we’ve seen so far.  I hope it will stimulate thought and discussion among other prairie managers looking for new ideas and options for dealing with prairie management challenges.

As I’ve said before on this blog, patch-burn grazing is not an appropriate management system for all prairies.  Moreover, patch-burn grazing often gets treated as a single narrow management system, but should really be seen as a basic template – and should rarely be implemented without tailoring it to meet particular objectives.   This new document describes some of the modifications of that template being tested at our sites and the responses we’ve seen from the prairie communities we manage.

If you’re interested, you can download the document here.

First Prescribed Fire of the Season

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To be perfectly honest, this post is mainly to build my own morale.  Last week, we were finally able to squeeze off our first prescribed fire of the season.  Typically, we get several good windows of opportunity during the month of March, but this year it was late in the month before the combination of wind, temperature, and relative humidity all lined up – and even then it was a very short window.  We woke up to temperatures in the mid 20’s and a couple hours after we wrapped up the fire we had thunder/lightning and sleet.  However, between late morning and mid-afternoon, we had very nice conditions for a prescribed fire.  It looks like that will be the only fire we get done in March – we have snow on the ground again, and while temperatures are forecast to rise toward the weekend, the wind speeds are too, making it unlikely we’ll burn again until at least next week. 

Looking at these photos from our successful first fire helps distract me from the list of other fires we’re still waiting to complete during the next couple of weeks (not to mention the long list of later-spring fires that will follow!)

The cold overcast conditions of the morning gave way to mostly sunny skies by early afternoon, which warmed and dried the grass and helped it burn more completely. For this fire, our burn crew size was bolstered by the addition of several staff from the nearby U.S. Fish and Wildlife Service Refuges office.

Our objective for the fire was to remove the thatch/litter from approximately 1/3 of the 175 acre prairie as part of our patch-burn grazing management. Beginning in early April, this site will be grazed by cattle, at a light/moderate stocking rate. Those cattle should graze the burned patch fairly intensively, while leaving the unburned patches largely ungrazed.

 

As the fire unit was finally ringed, a big plume of smoke rose into the air. Because our Platte River Prairies are near Interstate 80, we have to be very cautious about keeping smoke away from highway traffic. On this day, we had two things in our favor - the excellent lifting of the smoke (because of heat of the fire and the unstable atmosphere) and the east winds, which kept the smoke off of the Interstate to our north.

As the fire consumed the remaining grass inside the unit, our crew extinguished the last flames along the edges. We then began the long process of mopping up, which in a grazed prairie primarily means raking smoking piles of dried manure away from the edges of the fire unit. As we mopped up, we watched the half a dozen Swainson's hawks which, attracted by the smoke, had come to feed on the voles and other small mammals that were too slow to find new cover as they escaped from the fire.