EnviroHorse

Beating Bogus Biology*

Many times horsemen seeking to retain or expand access to trails are presented with unsubstantiated allegations that sound scientific but have no references provided. We scratch our heads and question: "Where did they come up with that?" The frightening part comes when land managers accept such allegations as gospel without further investigation.

Some examples:

• A county refused to rock trails on the advice of a native plant society that alleged that rocking altered the soil chemistry. The county did not have expertise to address this claim, nor funds to hire experts. Facing the abandonment of trails, EnviroHorse provided them with research to prove the allegation unfounded by science. See www.californiastatehorsemen.com/envirohorse.htm for paper on rock decomposition. We initially lost several rounds of argument during this process and ended up in community-based mediation before our view was accommodated and trails have been rocked consistently as needed since then.
• About 50 horses frequent this same park, none at pasture, all confined and fed oat hay or alfalfa. Native plant advocates had concerns that horses brought in the weeds in their manure. It turned out that the main invasive species of concern were yellow star thistle (toxic to horses), Italian thistle (teasel), and scotch broom-none of which horses ate. We pointed out to the county that if horses were involved in spreading weeds that they would have valuable crops of forage on their hands which they could sell and finance every single plant restoration project for the area. No forage feeds were growing in the park. This is a high wind area with over 70 bird species and numerous rodents. It receives 90,000 visitors annually and is adjacent to a freeway and heavily trafficked road. The county readily accepted that risk of weed spread by horses was infinitesimal compared to other vectors of weed seed spread.

• The federal government threatened closure of stables on public land due to coliforms in adjacent water that they said threatened endangered aquatic species downstream. Somehow they "forgot" that coliforms do not adversely impact aquatic species (they are more a human health concern), and in at least one instance, tests confirmed that the coliforms were coming from leaking human septic systems upstream of the horse facilities.

• Surfers concerned with coliforms where they swim pointed the finger at horse keeping facilities upstream. The horsemen and surf riders began meeting and establish a good-faith relationship. After a year of data collection it was conclusively proven that leaking sewer lines below the horses were the source of contamination. The water leaving the horse facilities was actually cleaner than when it entered from upstream.

• A really unattractive animal is the banana slug. It's a real creeper, often found on trails near the coast. Concern has been expressed about horses stepping on this 3-8" long, bright yellow, squishy looking critter. Would you let your horse step on one knowingly if you had to clean its hooves?

As you can see by the examples above, some of these allegations can be addressed by simple logic, but others require either finding or providing data and new science. When confronted with an allegation, first collect all the information about the issue that you can find from both the parties making the allegations and references that you find pertinent. I find myself reading bibliographies in articles as intently as the articles themselves. Your university agricultural extension or RCD may be able to help fill information gaps. Take this as "given": no one will know as much about horses as you do once you have done your homework. Throw in a little peer-reviewed science and you will be dynamite!

Undertake a risk assessment to put the problem into perspective so that others can understand the risk in relation to reality. There are three types of risks: true risk, calculated risk, and perceived risk. You are generally dealing with people's perceptions. Data and science are critical, if so. Look for analogies to put your position into perspective. Develop your position, or rebuttal to the allegation and run it by several people to test its soundness. Identify others who can help or support you. Turn out large crowds at public meetings. Script speakers from the audience to be sure and get certain points across in short sound bites. Be more orderly, polite and organized than your opponent. If you lose, persevere and appeal to higher levels.

Sometimes, just the personal interactions and good faith effort with the people with concerns can go a long way in resolving a problem. Try not to take the allegations personally, or over-react to them. Do not vilify or intentionally create enemies from opponents. It will consume too much of your energy and later they may seek revenge on other issues. You will be involved in a PROCESS not an event, and you must have patience to work through the process. Gather as much information as you can find on the topic under discussion

Unfortunately, the burden of proof to address spurious allegations involving horses always falls on the trail riding community. If these allegations are not adequately addressed, trails will be lost or never opened to you. The era of the passive horseman is over. The time that you could trust your government to act in your best interests is gone. If you have other instances of bogus biology, EnviroHorse would love to have their description and how you resolved them.

(*With thanks to S. Webel CoHoCo)

Junk vs. Real Science

For a real eye-rolling chuckle sometime, checkout the web for ten case studies on www.heartland.org/environment/jan00.regs.htm which spotlights rampant regulatory abuse based on junk science. Avoid using junk science results, even if it looks favorable to your cause. Discovery will lead to loss of credibility for your other arguments.

Your problem can become complicated when citations from real science in peer-reviewed journals are provided as references to substantiate negative claims about horses. We have found that it is very important to obtain and review the citations being quoted. The people who do not want horses on trails often find a reference, cull one statement out of it to support their position, and shut the book. Often other statements in the article are beneficial and can be used in your favor. Some of the publications reviewed below in the section on Annotated Bibliography looked initially incriminating when cited in anti-horse publications. But once read them entirely, they can actually be used to defend horses in many cases. It is perfectly legitimate for you to cull out the references that you wish to employ and use them selectively to make your point, just as your opponents do. A certain perverse satisfaction can accrue from using your opponent's own references against him!

Another thing we have seen is the tendency of anti-horse people not to look at or cite older articles. There is some mystique that "newer is better". However, for horses and trails, much of the research was done over 20 years ago and is as credible today as it was then. It keeps its flavor on the bedpost over night. Don't be afraid to cite and use it.

Relatively speaking, there are very few papers published specifically about horses. The following are peer-reviewed publications that have prompted further investigation on the part of EnviroHorse. If you have others, we would love to have both the paper and your comments. EnviroHorse has the goal of putting these references into database software called Reference Manager and making them available for free on the CSHA website. They will also be used to update existing EnviroHorse resource papers. The more citations saying the same thing, the more powerful the argument you can make. In many cases, SCIENCE will be the key to favorable decision-making about trail access.

Don't ever be afraid of the truth. The devil that you don't know is probably worse than the devil that you do know. If you know that something produces a negative impact, there is probably one or more management strategy that can be used to mitigate the undesired consequence. By putting your head in the sand and ignoring potential problems rather than addressing them with science, logic and conscientiousness, you prolong finding solutions, possibly exacerbate problems, and empower your enemies.

The Horsemen's Annotated Bibliography for the Defense of Trails

Please see references used in other EnviroHorse papers on our website. We go to some effort to document references so that you can use them without having to get original source papers. EnviroHorse has many of the documents you might need on a number of subjects. When the reference database is available, you will have a powerful tool at your fingertips. In a number of these papers we have tried to develop some concepts for use in risk assessments, and are always looking for other examples.

One particular green source has published a literature review on the negative impacts of recreational use of trails. A number of references cited in this paper implicate horses. The author assumes horses provide nutrient enrichment generically to weed seeds. She specifically cites the following paper that has nothing to do with horses:
"Influence of Nitrogen Loading and Species Composition on the Carbon Balance of Grasslands" Wedin, DA and D Tilman. Dec 6 1996. Science. V274. Pp1720-1723
Subject: how N impacts grasslands. It is a very complex study. I asked a professional soil scientist, Dr. I. Murarka, to review the paper and provide comments on how horses would be implicated, as this was unclear in reading of the document. Dr. Murarka confirmed that this study was about air borne nitrogen, which originates primarily from other sources (cars, etc.…no horses involved here). Its focus was on the concentration of N in the atmosphere, not deposition. The paper's thesis is that the more N in the air, the more gets up-taken by plants and stored in soils by fixation processes. This publication is not relevant to the Jordan allegation that trail horses provide nutrient enrichment to weed seeds.

"Cars, Cows and Checkerspot Butterflies: Nitrogen deposition and Management of Nutrient-Poor Grasslands for a Threated Species". Stuart Weiss. Conservation Biology. Pp 1476-86. Vol 13, No.6; December 1999. Dr. Weiss was a guest speaker at docent training I attended in 2002. He told an anecdote related to this paper in which the local utility company who owned the land was FORCED by the California State Dept and Fish and Game to begin active grazing of otherwise fallow land in order to control weeds. Yet, the previous author seeks to keep horses off of trails for fear of them depositing nitrogen.

These allegations prompted the EnviroHorse creation of two documents:" Horse Manure Aging and Nutrient Content and Implication for Trails", and "Horse Urine and Implication for Trails". While the first author is obviously a fine researcher in her own discipline, she failed to consider literally hundreds of existing older references available from the EPA, virtually every Ag school/extension in the country, agronomy and composting literature, and small body of literature specific to the horse. At no time does she attempt to do a risk assessment about the relative risks posed by either user groups or natural forces.

"Trail Corridors as Habitat and Conduits for Movement of Plant Species in RMNP, Co. Benninger-Truax, M., JL Vankat and RL Schaefer. 1992. Landscape Ecology. 6(4):269-278.
Subject: weeds tend to take hold on the edges of trail, particularly nearest to trailheads. This is a good paper. However, it does not specifically implicate horses until the very last sentence prior to the conclusion, when out of the blue it states: "Preliminary study indicates that some exotic species are dispersed in horse scat" and she cites her Masters Thesis. There is NO attempt to look at all vectors of weed seed spread including air, water, rodents and avians, which are all known to be the primary vectors of weed seed spread. This statement does not fit in this otherwise fine paper and is a pure hatchet job as written, so I ordered her Masters Thesis (see below).

"Trails as Conduits of Movement for Plant Species in Coniferous Forests of Rocky Mt. National Park, Co." Benninger, M. 1989. Miami of Ohio Univ.
Subject: disturbed trail edges can become corridors for invasive plant species and horses can be a dispersal mechanism for weed seeds. In this thesis she actually did a greenhouse study on seeds extracted from horse manure. Seeds from 15 plants grew, but only 8 were identified. While all 8 were exotic, NONE of them appeared in her test plots on the trail, although she observed them elsewhere along trails. She concludes that "horses MAY provide a means of entry of exotic species" but notes that the horses from the stable in the park which were not allowed to graze in the park and had controlled diets were not a problem. None of her references include analysis of weed seed survival. Benninger says seeds can pass through horses unharmed and be deposited in feces. Such seeds can be left in concentrated, mineral-rich patches along trails, where they may germinate after dung is decomposed (Janzen 1981, 1984). This has led to the assumption that manure is a major source of exotic species (Dale and Weaver 1974, Hammitt and Cole 1987); "however, I have found no documentation of this in the literature." Neither has EnviroHorse a decade later.

Harmon, G., and F. Keim. 1934. "The Percentage and Viability of Weed Seeds recovered in the Feces of Farm Animals and Their Longevity when Buried in Manure." American Society of Agronomy Vol. 26. Pp. 762-767.
Subject: barn animals were each fed 1000 weed seeds, chickens, sheep and horse guts seem to be able to destroy weed seeds more thoroughly than calves and hogs. An average of 14.2% of uninjured seeds was recovered, most within 48 hours of ingestion. Of these, only 6.7% were viable. The uninjured weed seeds were then buried in horse manure. At the end of one month, only velvet weed, bindweed, peppergrass, sweet bindweed and sweet clover were viable. The rest of the weeds were partially decomposed. Only the bindweed and sweet clover were viable at the end of the second month, but after 3 months only one weak bindweed seedling was obtained (1% viability). All other seeds were dead and had started to decompose at 4 months.

Janzen is one of the rare researchers who actually studied horses. We ordered both of his papers referenced in the Benninger thesis above.

"Seed Dispersal of Small Seeds by Big Herbivores: Foliage is the Fruit". Janzen, D. 1984. The American Naturalist. V1223, pp.338-353.
Subject: Large herbivores can spread seeds that can sprout from manure piles. Of interest to horses Janzen states:

• Most seeds are dry or otherwise inconspicuous and are not associated with specific dispersal agents (e.g., the horse) except for gravity, wind, surface water movement, soil erosion, birds, ants, dung beetles and rodents.
• Seeds must be sufficiently small, tough, hard and inconspicuous to escape the molar mill and spitting response of a large mammal. Seed coats must have the ability to resist digestion during a transit period of days to months. Horses are as
  likely to be an intense seed predator of seeds, as they are to be a possible dispersal agent.
• The longer the seeds are in the animal (or buried in composted dung), the higher the seed mortality.
• If a seed germinates immediately in the dung, the community of dung-degrading organisms may kill it.
• Severe mortality is likely through inter- and intraspecific crowding.
• In horses, the larger the seed, the longer it stays in the animal and the greater the chance that it will either killed by digestive processes or be found by seed predators searching dung.
• Large herbivores carry seeds inside them, not outside them in hair.

"Enterolobium Cyclocarpum Seed Passage Rate and Survival in Horses, Costa Rican Pleistocene Seed Dispersal Agents". Janzen, D. 1981. Ecology 62(3), pp. 593-601
Subject: could horses have played a role in spreading plants?
The issue of how long seeds remain in the horse gut is pretty well resolved in the literature. Most veterinarians will confirm that the bulk of food ingested passes through the horse gut within 48 hours (Argenzio et al 1974). However, seeds can live longer as demonstrated by this research. Four items were looked at in this experiment: seed survival, gut transit time, number of seeds defecated, and germination of scarified seeds. 57 brass buttons were also fed to these horses. Results of interest about horses were that

• The horses killed a substantial fraction of the seeds they swallowed through chewing and the inorganic acids and enzymes of digestion.
• "It is commonplace to speak of hard legume seeds as having "enhanced" or improved" germination after passing through a dispersal agent, owing to scarification of the seed coat. Given the state of knowledge of dispersal biology, such statements are premature and misleading. There is no intrinsic reason why an increase in the % of seeds germinating upon defecation is an "improvement" in the context of anyone but a farmer trying to grow seedlings. Success in the breaking of the dormancy of seeds is not necessarily measured by the length of the period of dormancy (inverse germination rate) but is based on a complex interaction with habitat and weather conditions at the time of germination."
• The primary sites of seed digestion in the horse are corners, folds, and eddy of the gut and the caecum. In the horse, the caeca somehow removes hard objects (and seeds) and retains them for unknown periods of time. Only one brass button out of 57 was voided in the 70-day study duration! Where are they now? Same place most of the seeds go?
• There is no evidence that passage through the horse "enhances" germination of surviving seeds
• Horse gut differs from cow gut. No horse had a seed passage rate anywhere near as fast, or a seed survival rate as high, as the cow.
• "While an Enterolobium seedling germinating in a dung pile is picturesque, its chances of surviving the dung beetles, mice, dryness, and root exposure characteristic of dung piles are very slim. In such a system it is not at all certain that scarification during passage through the mammal gut is the event that natural selection has favored during the evolution of the Enterolobium-disperser interaction."
• "The seed that is so impervious that the horse does not kill it by molar or chemical scarification may then be so slow to be scarified by soil processes that it has significantly fewer generations than the less impervious morph.
  He concludes that larger mammals may be effective in the long-distance transport of seeds, but that there is only anecdotal information on this topic.

Interestingly, in a recent bibliography obtained by Jerry Fruth of AERC from the BLM, Janzen was NEVER cited. But dozens of rather obscure Australian back bush studies were. Dr. Cyla Allison of EnviroHorse East is in the process of obtaining these documents and we will be analzying them shortly.

"The Assessment of a Biological System for Biodegradation and Recycling of Pesticide Wastes" by FE Woodrow, L Aston, T Shibamoto and J Beiber. (UC Davis and UNevada, Reno) It is unclear where published or date (Clearly after 1992, and possibly after 1996, by looking at the citations). The paper says Chapter 4 and Wastes, which seems to indicate perhaps a chapter in a book. Subject: horse manure is effective in degrading organic toxics. "Horse Manure was used as a digestion medium in the chamber because of the manure's large and diverse microbial population (22)." This citation is Anonymous, 1990. However, it is confirmed by www.agf.gov.bc.ca/resmgmt/fppa/pubs/environ/horse, which describes the horse gut as a "vast array of positive organisms". The results of this experiment are good: Not only were a wide variety of pesticides rapidly degraded, the manure itself also degraded through microbial activity so that no solid waste problem was created. The researchers suggest that horse manure may also be effective for the treatment of nuclear waste in ancillary publications.

Horses on trails are not a source of methane gas, of concern to greenhouse/global warming issues. "The primary source of methane release in livestock production is ruminant animals" www.nps.ars.usda.gov/ ARS Air Quality National Program

Foot and mouth disease (FMD) and Mad Cow Disease (BSE) are specific to cloven footed ruminants (sheep, cattle, goats) plus swine for FMD, not horses on trails. FMD is not zoonotic-people don't catch it. Horses imported from abroad from countries with FMD are quarantined 3-days and sponged with vinegar to kill any potential virus that may have been transported over on their hooves, but horses are not known to get this disease. During epidemics such as occurred in 2001, horses may be prohibited from import from countries with the disease. BSE comes from feeding ruminant protein to ruminants, which is prohibited in the US. There is no evidence that BSE spreads horizontally, i.e., by contact between unrelated adults and there have been NO cases in the US despite 10 years of surveillance amongst our own domestic ruminants. It's those imports you gotta watch! ). www.aphis.usda.gov

More to come! And see footnotes and risk assessments in our other papers.

Disclaimer

EnviroHorse has prepared these materials for information purposes
only and are not legal advice. Subscribers and online readers should not act
upon this information without seeking professional counsel. Every attempt has been made to assure that the information contained in this publication is accurate. EnviroHorse assumes no responsibility and disclaims any liability for any injury or damage resulting from the use or effect of any product or information specified in this publication.

About the Author

Adda Quinn was employed with a nationally known research institute for 21 years prior to her retirement. She has done research both on global climate change and contaminated soil and groundwater issues. As a trail advocate, she has provided research results in a variety of regulatory debates, both nationally and locally. She is a founding member of and on the Board of Directors for EnviroHorse. If you have any scientific studies that you think would be helpful, these papers are a work-in-progress and EnviroHorse would love to have copies of them. Please contact us at envirohorse@yahoo.com . If you have found these citations helpful, please consider a donation to EnviroHorse to help us find and sponsor more research. Papers will be in ELCR library soon. Website is at www.californiastatehorsemen.com/envirohorse.htm