Wild and Free-Roaming Horses and Burros Current Knowledge and Recommended Research. (1980) / Chapter Skim
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WILD EQUID RESEARCH AND MANAGEMENT METHODOLOGY
WILD EQUID RESEARCH AND MANAGEMENT METHODOLOGY
Pages 190-226
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From page 190... ...
Sampling considerations in behavioral studies, and the assay of blood chemistry to provide indices of nutritional state, both for research and management purposes, are explored at some length. STATE OF KNOWLEDGE Information Sources In addition to reviewing the published and unpublished sources described in previous chapters, Committee member Eberhardt visited l90
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From page 191... ...
With the exception of a few small-scale research studies, most current and recent efforts to census wild horses and burros have involved some form of aerial counting, and complete counts have usually been attempted. Doubtless this choice has evolved from considerations of cost-effectiveness, topography, and manpower limitations.
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From page 192... ...
A great deal of experience with African "game" has led workers there to use rather narrow strips for aerial counts, and to depend on sampling rather than attempting complete counts (cf. Sinclair l972, Goddard l967)
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From page 193... ...
That may be dealt with by careful mapping of locations from both air and ground. In censusing wild horses, band size and coloration of particular individuals could be used to aid in checking the identity of given bands.
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From page 194... ...
Also, if complete counts are attempted, there should be no need to conduct a special auxiliary survey of this type. All that is needed is to be sure that the observers do tally any marked animals.
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From page 195... ...
While most of the current work on equid census attempts complete counts, there may be situations in which accurate, complete counts are not practical or feasible, and in which some sampling approach might be appropriate. Far more wildlife census work depends on sampling procedures than on complete counts.
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From page 196... ...
and, if possible, seeking to "calibrate" or adjust such counts for the fraction missed. The same approaches discussed above under "Complete Counts" apply to the plot-sampling methods.
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From page 197... ...
One source of bias not yet investigated in wild horse and burro censusing is the likely effect of group size on visibility. This problem actually subdivides into two kinds of bias.
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From page 198... ...
The appraisal of variability is obviously a critical issue in the overall problem of censusing wild horses and burros. If an unbiased method turns out to give extremely variable results, then it may be preferable to use a somewhat more biased
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From page 199... ...
Preliminary Analysis of BLM and USFS Census Data The accuracy and precision of existing horse and burro census procedures need to be investigated in connection with the proposed research on this subject (Project l7)
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From page 200... ...
Since wild horse foals are dropped seasonally, counts in March and August of even the same year could vary by l5 or 20 percent. It is a basic principle in censusing animal populations that inferences about year-to-year trends and comparisons between areas must be based on censuses taken at the same season each year, or at the same stage in the annual life cycle.
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From page 201... ...
About one-third of the animals they observed were marked, and the inference drawn was that typical aerial census operations for burros could be expected to count only about one-third of the animals present. The authors also suggested that a mark-resight method would be more appropriate for burro census than attempts at total counts.
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From page 202... ...
However, many domestic horses were legally licensed to use public lands. Since l97l, BLM and USFS range managers have had a legal mandate to manage wild horses and burros to achieve and maintain "a thriving natural ecological balance on the public lands" (U.S.
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From page 203... ...
Thus range condition and forage competition with other herbivores were not direct considerations. The remaining eight wild horse reductions were proposed primarily for the purpose of either correcting depleted or unsatisfactory range condition and overutilization of forage, or adjusting existing horse populations "to numbers established in the land-use plan." Few of the plans and EARs provided much information to support the contention that range conditions were unsatisfactory or explained how those conditions were determined.
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From page 204... ...
has been the basis for most of the laboratory analysis of horse feces carried out in the western United States since their paper appeared. Inferences about dietary composition based on fecal analysis should be drawn cautiously until the technique is further validated with a proven procedure such as microscopic analysis of fistula extrusa (Theurer and others l976)
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From page 205... ...
Most researchers who have dealt with diet analysis, by one technique or another, will readily admit that selectively feeding herbivores often ingest considerable quantities of plant species that the researcher finds difficult or nearly impossible to locate, even by intensive systematic sampling of the plant community. Consequently, reference collections often lack representation of a few plant species that may, on occasion, contribute significantly to diets.
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From page 206... ...
In-vitro approaches, while possibly less accurate than in-vivo techniques, are often the most practical in situations where the forages are difficult to collect in sufficient quantities for feeding trials. However, we know of no in-vitro procedures that have been specifically modeled after equid digestive physiology.
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From page 207... ...
would provide a valuable departure point for research on such an approach. Blood Assays as Possible Indices of Nutritional State in Horses and Burros Assays of easily taken blood samples may have potential both for evaluating the nutritional condition of individual animals and for using an animal's condition to indicate nutritional adequacy of the range (Seal l977)
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From page 208... ...
The pasture grass contained approximately 3.2 percent protein and the supplements contained l2 to l5 percent protein. Six of eight animals maintained on grass alone exhibited estrus, but only two of these ovulated and both conceived.
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From page 209... ...
These results imply the desirability of analyzing data from captured wild animals in terms of season and lipid metabolism. There is no evidence that season affects serum urea nitrogen unless the animals are on pasture without supplementation (Owen and others l978)
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From page 210... ...
An overall lack of comparability severely limits the ability of researchers to generalize their experimental findings to wild populations. A primary goal of the behavioral sampling scheme is to establish a set of data that are comparable across experiments.
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From page 211... ...
Furthermore, the work time necessary to characterize population responses by means of focal-animal sampling is great. The series of experiments in the recommended research projects will require both the ability to characterize behavioral differences across treatments (i.e., mean treatment responses)
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From page 212... ...
The second decision in behavioral sampling is that of how to record the behavior. Again, two techniques are commonly used.
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From page 213... ...
FSP Sampling Scheme l. Behaviors to be Recorded.
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From page 214... ...
. Behavioral Sampling for Specific Experiments Contraceptive Experiments on Penned Animals l.
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From page 215... ...
In these samples the onset, termination, and sequence of all behaviors (see subsections on the FSP sampling scheme and the contraceptive experiments for behavioral categories) should be recorded against a real-timed record.
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From page 216... ...
Activity is to be compared to levels in the feeding trials to determine how range conditions comparable to feeding levels would affect animals active under free-ranging conditions. Feeding behavior is to be compared with that measured in the small enclosures to determine if the feeding responses are similar in the enclosed and free-roaming condition.
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From page 217... ...
Since observational conditions and habituation of the animals to human observers will differ widely in free-roaming populations, a strict sample scheme cannot be projected at this time. The researcher should employ the same sampling methods and schedule for continuous focal studies as are used in the experiments to which comparisons will be made (i.e., sexual behavior should be recorded as per the instructions outlined in contraceptive experiments, feeding behavior as described under the small-enclosure feeding trials, etc.)
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From page 218... ...
Fertility control or sterilization of the harem stallion has been suggested as a means of limiting the growth rates of wild horse populations. This approach is based on the premises that the females of a harem or band are bred only by this male and that this social structure is in some measure constant.
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From page 219... ...
Other compounds tested in domestic horses include chlormadinone acetate (Arbeiter and Jochle l975) and an orally administered synthetic progestin, l7-a-allyl-estratiene-4-9-ll, l7-B-ol-3-one (Webel l975)
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From page 220... ...
Studies of domestic mares to determine the effectiveness of this approach might employ the following design: use animals with proven reproductive histories, install the implants, observe the animals for signs of estrus, collect blood samples for hormone assay, use rectal palpation or serum progesterone to determine if ovulation has occurred, test with a stallion to detect behavioral responses characteristic of estrus, and test for pregnancy if breeding occurs. It is possible that estrous behavior might occur but that ovulation might not.
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From page 221... ...
Xylazine, in combination with hetamine, has been used for anesthesia of domestic horses. The combination is also being used for immobilization of many wild species and may be useful for wild equids.
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From page 222... ...
Complete counts, including bounded counts b. Mark-resight estimates c.
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From page 223... ...
First priority should go to the mark-and-resight effort as a check on the complete counts. However, strip transects may be deemed especially suitable for some sites.
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From page 224... ...
Contraception Studies Rationale Those who manage wild equids will have to deal with multiple populations of differing size, composition, and accessibility. If population control is desired, but removal techniques cannot be applied, contraception might be a useful technique.
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From page 225... ...
Blood chemistry High priority Lower priority Serum urea nitrogen Free fatty acids (NEFA) Glucose Ketones Triglycerides Haptoglobin Serum protein and albumin Transferrin Uric acid CPK Bilirubin Behavior Detailed guidance for measuring behavior can be found earlier in this chapter ("Behavioral Sampling for Specific Experiments: Contraceptive Experiments on Penned Animals," and in Chapter 2 ("Project 6: "Methodology," paragraph 4)
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