A Comprehensive Annotated List of the Butterflies
Little Missouri National Grassland Butterfly Survey
Study Area and Methods of Sampling
The site of this study was lands within the general extent of the Little Missouri National Grassland in southwestern North Dakota. Two different sampling procedures were employed in 1995 in an effort to confirm occurence of as many species as possible over as wide a range as possible. The two methods are referred to respectively as "Pollard transect" (or simply "transect") and "checklist" methods. In order to ensure adequate replication, only one Pollard transect was employed in 1995 in each of two locations, one in the southern part of the grassland at Burning Coal Vein Campground in Slope County, and the other in the northern part of the grassland, at Summit Campground in McKenzie County. Both locations, as well as other more widely dispersed situations, were also checklist surveyed during the 1995 season. In 1996, the checklist method was dropped, and surveying focused on two nearly identical transects situated at the Summit Campground location only. The two methods (1995) or two transect paths (1996) were surveyed in an alternating pattern so that data could later be compared statistically.
The 1995 Summit Campground transect (S001) was 800 meters long, beginning approximately 200 meters SW of the campground proper (47°-34'-37"N x 103°-14'-36"W), in the S1/2 of NW1/4, Section 24, T147N R99W. The 1995 Burning Coal Vein Campground transect (BCV001) was 700 meters in length, beginning at the eastern end of the parking lot at the Columnar Junipers Overlook southeast of the campground proper, in the SE1/4 of the NW1/4, Section 13 T136N R102W. In 1996, a second, topographically congruent and ecologically equivalent 800m transect (S002), was set up approximately 180m SE of the first (47°-32'-29"N x 103°-14'-30"W) at Summit Campground. Each of these three transects was marked off in flagged 10-meter segments and, where possible, with more permanent 100-meter reference posts (inverted metal electric fence posts).
For the checklist sampling method employed in 1995, a hypothetical list of regularly breeding resident species was first compiled for the entire grassland. The hypothetical list was derived from formal records for all included and adjacent counties. Excluded were occasional non-overwintering immigrant species. Native species for which it seemed likely that the absence of records represented incompleteness of information rather than actual absence were included in the hypothetical list and likewise in both editions of this list on the assumption that they will likely be confirmed at some time in the future. A separate reporting form was used for each checklist walk.
Each transect was represented schematically on the reporting form by a series of vertical linear scales, each divided into 10 segments corresponding to the 10-meter flagged segments on the ground. These scaled sections (0-100 meters) allow one to use the form to "walk" mentally through the transect and spatially envision each recorded encounter. Date, name of reporter, start time, finish time, temperature, estimated sunshine (10% increments), wind direction (eight points) and wind speed (Beaufort Scale) were all recorded at the finish of each transect walk. A separate reporting form was used for each transect walk.
Counting procedures for the two methods were identical in all respects except one, namely that in the transect method the recorder walked only along the designated transect route, whereas in the checklist method the recorder was free to wander at will. Procedures for 1996 transect counts were identical to those employed in 1995. Protocols for counting and recording in all situations generally followed Pollard and Yates (1993), Monitoring Butterflies for Ecology and Conservation:
- The sampling day extended from approximately 9 am until 5 pm.
- At the beginning of the day, a coin was flipped in order to determine which method or transect was to be employed first; methods or transects were thereafter alternated throughout the day.
- Butterflies were recorded with encoded four-letter acronyms (see appendix) later used in database management.
- No voucher specimens were collected within 100 meters of any point on a transect.
- The walking pace was steady and regular at approximately 35 meters per minute.
- Only butterflies actually seen within an estimated 2.5 meters on either side of the recorder, within 5 meters above the ground, and within 5 meters to the front were counted; butterflies behind the recorder or otherwise outside these limits were never counted.
- No active pursuit was undertaken, and no effort was made to find or to see butterflies hidden from view or perched out of sight of the recorder.
- A net was carried, and when problem individuals could be netted without undue difficulty or active pursuit, they were netted and released after identification had been made (in such cases, counting was stopped until the walk was resumed).
- Where distinction between two alternative species was not possible, the commoner of the two options (for that period of the season and the site in question) was recorded.
- For each case involving more than two such alternatives, identification was made to the lowest confident taxonomic level practicable.
- When individuals flew ahead of the recorder, when the recorder was certain that they had already been counted, they were ignored; if the recorder was uncertain, they were counted.
Table I. Summary of butterfly counts at Burning Coal Vein Campground, Summer 1995 28 May 5 transect counts (GAH) 1 checklist count (GAH) 05 June 6 transect counts (GAH) 6 checklist counts (GAH) 19 June 4 transect counts (GAH) 4 checklist counts (GAH) 26 June 6 transect counts (GAH) 5 checklist counts (GAH) 02 July 4 transect counts (GAH) 3 checklist counts (GAH) 17 July 4 transect counts (GAH) 4 checklist counts (GAH) 24 July 5 transect counts (GAH) 3 checklist counts (GAH) 31 July 6 transect counts (GAH) 5 checklist counts (GAH) 17 August 3 transect counts (RAR) 2 checklist counts (RAR) Table II. Summary of butterfly counts at Summit Campground, Summer 1995 29 May 6 transect counts (GAH) 5 checklist counts (GAH) 05 June 0 transect count (RAR) 1 checklist count (RAR) 06 June 5 transect counts (GAH) 5 checklist counts (GAH) 20 June 1 transect count (GAH) 1 checklist count (GAH) 27 June 4 transect counts (GAH) 4 checklist counts (GAH) 10 July 2 transect counts (GAH) 2 checklist counts (GAH) 18 July 2 transect counts (GAH) 3 checklist counts (GAH) 25 July 2 transect counts (GAH) 4 checklist counts (GAH) 01 August 4 transect counts (GAH) 4 checklist counts (GAH) 18 August 0 transect counts (RAR) 1 checklist count (RAR) Table III. Transect butterfly counts at Summit Campground, Summer 1996, with Two-year summary for all counts in the Little Missouri National Grassland. Date Transect S001 Transect S002 Two-year Summary 19 May 4 counts 4 counts 05 Jun 4 counts 4 counts Total 1995 BCV Cg. counts: 76 18 Jun 3 counts 3 counts Total 1995 Summit counts: 56 29 Jun 3 counts 3 counts Total 1996 Summit counts: 55 09 Jul 3 counts 3 counts 28 Jul 0 counts 5 counts Total both years all sites: 187 07 Aug 4 counts 4 counts 19 Aug 4 counts 4 counts
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