Thursday, August 30, 2012

Inside/Outside a Deer Exclosure

Sampling continues, with the latest round of visits to a series of deer exclosures that were established in the 1980s. I've sampled these exclosures for four years now, and have a stockpile of data that show a continual upswing in the deer problem. Missouri's woodlands are beginning to look like certain urban areas where the understory consists of a small list of sedges, Panic grasses, and maybe one or two low C-value forbs (and bush honeyscukle and wintercreeper, of course). The deer problem in Missouri continues to escalate, and I'm just gathering data, writing testamony.


Photos below from a terrific fen complex with Fuirena simplex, lots of Rudbeckia fulgida, grass of Parnassus, etc. The first 3 photos are from inside the cattle panel cage (held together with 10 gauge baling wire, wrapped to fenceposts. This requires climbing into the exclosure, of course). [These exclosures are easy to construct (and affordable) if you, too, wanted to measure deer impacts on your property.] A suite of forbs in the area are restricted to inside the exclosure (grass of Parnassus, Aster praealtus, Lysimachia, Physalis), and while the landscape is the same on the other side of the fence, these plants are missing from the outside of the fence, having been browsed so severely that these and other species have been extirpated. Inside the exclosure all forbs were erect and blooming or in bud, and not exhibiting multibranching or sprawling habits that are the direct results of deer overbrowse. The third photo is of E. perfoliatum inside the exclosure which the deer snipped off because it was so close to an opening in the cattle panel.








In this fen, ice cream plants for deer include: R. fulgida, E. perfoliatum, A. azureus, H. autumnale. These plants were browsed so severely that they will not flower this year. I couldn't capture the scale of the significant browse, as it exists throughout the entire fen. Deer apparently do not like F. simplex and juncus. And even cows don't like Vernonia! But the deer have hit the Vernonia pretty hard, too. The Fuirena has expanded exponentially this year with the competing forbs having been browsed so much in recent years that it (and Juncus, Scirpus) have grown into massive populations. [Similarly, in dry mesic woodlands here, Diarrhena americana and Sanicula gregaria have colonized an entire woodland floor in the absence of other plants.] A few photos from outside the exclosure:




 I love sampling inside the exclosures, as they're generally remarkably different from outside the cattle panels these days.

3 comments:

azta110790 said...

Do you have any suggestions on how to deal with the deer problem?

Allison Vaughn said...

Because we no longer have a predator/prey relationship in the lower 48, long time deer researcher Rooney (UW-Madison) and others have suggested that the control of the deer problem now rests in the hands of state wildlife agencies and hunting regulations. Unfortunately, the impacts of deer browse on biodiversity is currently not a metric in many state wildlife agencies' measure of deer problems, relegated instead to car collisions and farm impacts. The first step is to monitor the impacts to biodiversity, which, today, are significant. I do have suggestions, but I am not at liberty to suggest...

Anonymous said...

This issue is easily solved...enable the individual landowner the freedom to harvest more deer on their property without more permits, taxes, etc...but oh wait, the central planners don't want to lose control :(