>From a colleague in Natural Resources Conservation Service (NRCS): There’s a big difference between grazing “rangeland” vs “pastureland”, which may account for the highly variable results in the literature. Rangeland <https://www.nrcs.usda.gov/wps/portal/nrcs/detail/national/home/?cid=stelprdb1253602> primarily consists of native vegetation in an expansive area, generally occurring west of Minnesota, Iowa, Missouri, Arkansas, and Louisiana and in portions of central and southern Florida. To the east, grazing lands are referred to as pasture, which are smaller in size and commonly consist of non-native forages. There has been success in expressing residual native plants in Iowa pasture after the removal of cattle (or lowering stocking rates) and reintroduction of fire.
· Dr. Diane Debinski ( Iowa State University), Ryan Harr (Iowa DNR), and Dr. Miller (University of Illinois) conducted research on patch burn grazing and effects on plants and invertebrates in southern Iowa pastures. · Dr. Thomas Rosburg from Drake University conducted his dissertation research on native plants in southern Iowa pastures. He also conducted a study on plant community response to grazing on a reed canarygrass invaded Wetland Reserve Program site in Iowa. The study included exclusion fencing (control), different grazing treatments, and seedbank essays. Dr. Keith Summerville (Drake) was also involved, he monitored the response of fauna. Regardless of a rangeland or pastureland status, NRCS has Grassland Specialists who can assist in the development of a prescribed grazing plan to meet specific objectives. I’d encourage anyone interested in this topic to contact their local NRCS office, who can put them in touch with one of these specialists. On Mon, Jan 15, 2018 at 4:42 PM, David Inouye <[email protected]> wrote: > A summary of responses to my query last month: > On Dec 16, 2017, at 2:57 AM, David Inouye <[email protected]> > <[email protected]> wrote: > > Can anyone comment on the validity of this statement about effects of grazing? > > "Suggesting that landscapes will return to natives by removing livestock is > not substantiated by research." > > It's from a letter from my county commissioners in response to a draft > National Forest management plan. > > Thanks. > > David > > > I wrote an article in Conservation Biology in 2002 entitled Grazing, Rest, > and Restoration (attached below) that reviews the arguments that landscape > recover following grazing. Of course this is just a small piece of a very > large and complex issue, I tried to succinctly address the core ideas in a > short and pithy article. The bottom line is, especially in light of climate > change, landscapes typically do not recover on their own and sometimes > judicious use of practices such as fire and grazing can speed recovery. Of > course every landscape is somewhat different, for the Southwest D. Milchunas > wrote a review for the Forest Service in 2006 that exhaustively considers > this topic. There are a number of other reviews out. > ***************** > > Although I am not an expert in rangeland ecology, a quick scan of the > literature is enough to allow me to answer your question with another. What > time scale do you (they) have in mind? It appears that, in semi-arid > grasslands, change post-grazing is slow and multiple trajectories are > possible. Trajectories depend on local conditions (edaphic parameters, > degree and duration of grazing pressure, nature of grazing community and, > perhaps, climate change pressure), so no unqualified blanket statement (such > as you quote) seems justified unless you are cherry-picking to support a > foregone conclusion. One factor that might be applicable is this. Will the > rangeland affected be managed for restoration post-grazing or will it be > subject to “benign neglect." > ***************** > > >From my own personal experience, removing disturbances such as livestock > >from an area does, indeed, result in the return of native plants and > >animals. It does also, however, provide an opportunity for invasive plants > >to become established, so assisting the colonization of native plants helps > >establish a community less prone to invasives. > ***************** > > > Welcome to the vociferous debate about 'regenerative grazing', > 'intensively managed grazing', 'holistic management', Alan Savory, Richard > Teague vs. Brisk & Holloway, and others. > > There seems to be plenty of traditional research to indicate that grazing > livestock destroy rangelands, and a growing body of anecdotal/rancher-led > evidence (and active research) in development that is suggesting otherwise. > Kristina Wolf in Sonoma County could likely comment further based on work > at Pepperwood Preserve where cattle are used specifically to restore native > California bunch grasses. I have worked with targeted goat graziers in > Alberta to slow/stop spread of invasives and support return of native > grasses, but nothing published. There are many other examples but careful > documentation is rarer. > > It depends on which natives, in part - woody species may recover when > protected from grazing; bunch and other perennial grasses seem to suffer > from a lack of *appropriately timed *grazing impact. That is - grazed > once or twice a year to remove biomass, but protected from overgrazing by > removing livestock before they get a 'second bite' chance that cuts into > young and growing tissue still in a recovery phase. > > I think I'd like to leave it there and catch up on my background research > before going further, but this is definitely an active discussion and there > is be evidence on both sides. It seems largely to amount to how we manage > (or don't manage) livestock grazing - timing (duration, time of year, > timing of rain/precipitation and plant phenology), number of animals, > species, and native ecology - and experimental set-up, i.e. using an > adaptive management, whole-landscape and context-driven approach or a small > plot, context-independent approach. > > I'm pretty sure that doesn't help clarify but may give you a start... > **************** > > Usually rehabilitation of a landscape that has been over grazed is more > involved than merely removing the initial degradation factor (livestock > grazing). The complexities of restoring an ecosystem to its natural state > depends on the current state of the landscape; native plants present, > invasive noxious weeds present, native animals present, the condition of > the soil, etc. > > ****************** > > That statement is simplistic. In some cases removing livestock could allow > natives to recover. As I suppose you would imagine, the consequence of > removing livestock would depend on the biome type, the composition of the > native vegetation in the location, and also the history of livestock grazing, > including how long the area had been grazed and how intensively it had been > grazed. > > I manage a prairie restoration, but I don't have a history of publishing on > the effects of livestock grazing on plant community structure. I imagine that > you have received messages from others who have much more experience. > > Thanks for all you do for ecology and ecologists. > ****************** > > This may or may not be applicable, but removing horse grazing resulted > in the return of natives in this study: > > Beever, E., Tausch, R. and Thogmartin, W. 2008. Multi-scale responses of > vegetation to removal of horse grazing from Great Basin (USA) mountain > ranges. Plant Ecology 196:163-184. > > Hope this helps. > > ******************** > > > > -- > Dr. David W. Inouye > Professor Emeritus > Department of Biology > University of Maryland > > Principal Investigator > Rocky Mountain Biological Laboratory > >
