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Re: [RC] Horse Manure and Weeds - Linda MiramsOn Wed, 2 May 2007 09:31:05 -0500, Dawn Carrie wrote Can anyone direct me to the info posted a while back on the study(s) of horse manure and the spread of noxious weeds?... ...I've been asked for input by Texas Parks and Wildlife Department on the potential for horses to spread invasives... This issue has acquired particular importance since President Bill Clinton signed US Presidential Executive Order 13112 on February 3, 1999. See it at <a href="http://www.vic.com/~lbm/EO13112-1999.htm";> http://www.vic.com/~lbm/EO13112-1999.htm</a>. An Executive Order is not a law. It is not a legally-promulgated regulation (announced in the Federal Register and subject to public comment, etc.). It is essentially the President ordering all of the Executive Branch agencies that work for him to do something, rather like the president of a corporation ordering all employees of that corporation to do something, such as implement a stated policy. Executive Orders nevertheless have far-reaching consequences. For example, there never was a law permitting federal agencies to restrict Off Highway Vehicles on federal land (except for federally- designated Wilderness Areas). I don't believe there was ever even a federal regulation restricting OHV's. Yet for 35+ years OHVs have been subject to the greatest restrictions of all on federal lands. The legal underpinning for all the OHV rules in land management plans was nothing more than President Richard Nixon's Executive Order 11644, signed in 1972! EO13112 gives those who want to restrict horses on public lands an irresistibly attractive legal tool to justify those restrictions. It is attractive because: - It allows people to focus their sense of self-righteousness on exactly the same object (horse manure) that is the focus of their ire. (The "yuck" factor described by so many hikers.) - It is an idea with incredibly powerful, immediate intuitive appeal. I saw this effect when the horse manure=self-fertilizing invasive seeds scenario was first broached by land managers at a mountain bike meeting. The mountain bikers' eyes just lit up. It made such perfect *sense*! It takes a *lot* to disabuse someone of this notion after they have heard it, even once. - Invasives being spread by viable seeds deposited on trails in manure gets all mixed up with what is actually a separate, but far more scientifically valid scenario: undigested viable seeds present in hay carried as fodder for packstock spilling at trailheads and backcountry campsites. This latter scenario is easier to cope with (certified weed-free hay, beet pulp, pelletized feeds) and still keep horse access to trails. - While this is a Federal Executive Order, its effect spills over into state land management decisions. First, because state land managers can spot a good thing when they hear it. Second, because many *state* operations are actually substantially funded by *federal* money. This is most particularly true of state Fish & Wildlife operations. Here are some talking points to help make people stop and think before they blindly latch onto this notion: 1. The old "For every problem, there is a solution that is neat, elegant, plausible,...and wrong!" dictum. 2. It is true, but it is *not* anywhere near as true as people like/hope to think it is. This is where studies like the AERC study can help, although you will get some backwash because the study was funded by a group with a vested interest in disproving the theory. Point out that it was done by a professor at a public university, not by some results-for-hire private consulting firm. Has this paper been published in a peer-reviewed environmental journal? Even better. 3. Most invasives are spread by wildlife such as birds, deer, and even bees, and by mechanical means such as windborn seed from abutting land, often residential properties planted with ornamentals. Hikers/mountain bikers are most definitely a source of invasive spread along trail systems: the seeds are embedded in the dirt packed into their shoes and tires (and hooves). The source can be parking lots at trail heads, or the hiker's own front lawn. Land managers often state that they want to prevent the spread of tall fescue. What do you think is growing in the front yard of 95% of hikers, mountain bikers, and land managers? 4. Most of the very persistent and noxious invasives (privet, oriental bittersweet, wineberry, Nepalese Browntop grass, and many-if-not-most others) are NOT eaten by horses! Horses are grazers, not browsers like deer. Nothing eats Nepalese browntop. The seeds for these items will never get into a horse's digestive track, never mind survive to viability in deposited manure. Despite what I have been told, I have never seen my horses or my brother-in-law's cows eat tropical soda apple seedpods. If there is a vector of transmission for these invasives relevant to horses, it is their spread from hay harvested from land already invaded. They survive to viability in pastures where the buyer puts the infested hay out precisely because the horses don't eat it! 5. As grazers, horses crop grass in a pasture before it ever matures to set seed. 6. Always question any assertion that there is "scientific evidence" that horses spread invasives. Politely insist the person supply the scientific citations. Don't accept any statement that boils down to "But everybody knows it's true." There are almost no studies on this question that actually did experiments with horses. The very few studies there were were about cattle (ruminants; horses are not ruminants), which casually mentioned that the same results probably applied to horses. Suddenly, everbody writing on this topic starts saying that horses spread invasives, citing this same paper. Then, people cite the articles that cited the original paper. But what starts looking like a blizzard of papers appearing in scientific and environmental journals proving horses spread invasives *more than hikers/hunters on OHVs with muddy tires/logging trucks/birds* turns out to be a house of cards. There is a lot about this topic that starts resembling a "Green Urban Legend." 7. Just because invasives are present on a horse trail does not mean the horses put them there. Many invasives (kudzu, oriental bittersweet, Japanese cogon grass) were actually deliberately planted by the land management agencies in decades past for erosion control or as fodder to encourage wildlife in tended feedlots. 8. Even with all this, you will still have trouble dislodging this so-intuitively attractive conviction. One of the weirdest things I've seen was a study undertaken at Great Smokey Mountain National Park that did everything it could to prove that invasives were more common at hiker+horse campsites than hiker-only campsites in the backcountry trail system. Despite a horribly biased sample, the results showed *NO STATISTICALLY SIGNIFICANT* correlation between the presence and quantity of invasives and the presence of horses at campsites. None. Zip. Flat. Yet even when their data disproved their theory, the authors of this study still advocated making land management decisions that restricted horses essentially because it was so plausible an idea that it just *had* to be true. Moreover, I have heard two different US Forest Service personnel from different regions refer to this Great Smokey Mountain study as "proof that horses spread invasives"!!! It's like they never read the paper, or if they read it, they didn't understand what it said! Weird. 9. Demonstrate to your opponents that you understand the seriousness of the invasives problem. In fact, a modern horseowner, particularly one who maintains open space by grazing their horses on pasture, is probably far more personally affected by invasives than most of the hikers/mountain bikers in the room with you. Tall fescue causes abortions in pregnant mares. The year my mare was pregnant I had to import hay from as far away as Washington State and Michigan because the local hay is almost all from tall fescue fields. Nepalese browntop will turn a rich pasture into a green desert, inedible to both livestock and wildlife, in less than a decade. It's happening to my brother-in-law's family farm right now. It isn't that non-native invasive species aren't a real problem. They are. Once you become aware of them, you will notice that they are everywhere, in frighteningly large numbers. But it is necessary to keep things in perspective: horse manure on trails is not a significant spreading vector, especially not when compared with all the other mechanisms at work. A land manager who forbids horse manure has done essentially nothing real to mitigate their non-native invasives problem. They've just made some hikers happy, and fibbed to themselves. We can't let ourselves be made the scapegoat! Linda Mirams =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= Ridecamp is a service of Endurance Net, http://www.endurance.net. Information, Policy, Disclaimer: http://www.endurance.net/Ridecamp Subscribe/Unsubscribe http://www.endurance.net/ridecamp/logon.asp Ride Long and Ride Safe!! =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
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