Summary Information
Rabbit Population Densities at the Sevilleta National Wildlife Refuge, New Mexico (1992-2004)
Creator: Individual: Robert Parmenter Organization: Valles Caldera National Preserve Physical Address: Delivery Address: P.O. Box 359, 090 Villa Louis Martin City: Jemez Springs Locality: NM Postal Code: 87025 Phone: US Email: bparmenter@vallescaldera.gov
Metadata Provider: Individual: Information Manager Sevilleta LTER Physical Address: Delivery Address: 1 University of New Mexico City: Albuquerque Postal Code: 87131 Phone: US Phone: (505) 277-2109 Phone: (505) 277.5355 Email: data-use@sevilleta.unm.edu
Associated Party: Individual: Sevilleta LTER Field Crew Sevilleta LTER Field Crew Physical Address: Phone: US Email: data-use@sevilleta.unm.edu Role: field crew
Associated Party: Individual: Robert Parmenter Organization: Valles Caldera National Preserve Physical Address: Delivery Address: P.O. Box 359, 090 Villa Louis Martin City: Jemez Springs Locality: NM Postal Code: 87025 Phone: US Email: bparmenter@vallescaldera.gov Role: lab crew
Publication Date:	2014-01-27
Language:	English
Abstract: This study measured the population dynamics of black-tail jackrabbits (Lepus californicus) and desert cottontail rabbits (Sylvilagus auduboni) in the grasslands and creosote shrublands of McKenzie Flats, Sevilleta National Wildlife Refuge.  The study was begun in January, 1992, and continued quarterly each year.  Rabbits were sampled via night-time spotlight transect sampling along the roads of McKenzie Flats during winter, spring, summer, and fall of each year.  The entire road transect was 21.5 miles in length. Measurements of perpendicular distance of each rabbit from the center of the road were used to estimate densities (number of rabbits per square kilometer) via Program DISTANCE.  Results from 1992 to 2002 indicated that spring was the peak density period of the year, with generally steady declines through the year until the following spring. Evidence of a long-term "cycle" (e.g., the 11 year cycle reported for rabbits in the Great Basin Desert) did not appear in the Sevilleta rabbit populations.
Keywords: Keyword: populations Keyword Thesaurus: Core Areas
Keywords: Keyword: populations Keyword: measurements Keyword: long term Keyword: surface elevation table Keyword: surveys Keyword: roads Keyword: deserts Keyword: grasslands Keyword: rabbits Keyword Thesaurus: LTER Controlled Vocabulary
Intellectual Rights: Data Policies This dataset is released to the public and may be freely downloaded. Please keep the designated contact person informed of any plans to use the dataset. Consultation or collaboration with the original investigators is strongly encouraged. Publications and data products that make use of the dataset must include proper acknowledgement of the Sevilleta LTER. A copy of any publications using these data must be supplied to the Sevilleta LTER Information Manager.
Distribution: Online: URL: http://sevdeims-d.lternet.edu/data/sev-113
Coverage: Geographic Goverage: Geographic Description: McKenzie Flats is located within the northeastern section of the Sevilleta NWR, encompassing an area from Black Butte south to Palo Duro Canyon and east to the Los Pinos. Bounding Coordinates: West Bounding Coordinates: -106.691 East Bounding Coordinates: -106.691 North Bounding Coordinates: 34.3592 South Bounding Coordinates: 34.3592 Bounding Altitude: Altitude Minimum: 1615 Altitude Maximum: 1615 Altitude Units: meter Temporal Coverage: Date Range: Begin Date: Calendar Date: 1992-01-20 End Date: Calendar Date: 2004-05-03
Purpose:
The purpose of the study was to assess the dynamics of rabbit populations in the grasslands and creosote shrublands of the Sevilleta NWR.  Rabbits are important herbivores in these habitats, and can influence NPP and plant species composition.  In turn, these animals also provide high-quality prey for many of the Sevilleta's mammal and reptile carnivores and birds of prey.  Density data on rabbits can be used to calculate herbivore pressure on the plant communities.
Contact: Position Title: Information Manager Organization: LTER Network Office Physical Address: Delivery Address: UNM Biology Department, MSC03-2020 Delivery Address: 1 University of New Mexico City: Albuquerque Locality: NM Postal Code: 87131-0001 Phone: USA Phone: 505 277-2535 Phone: 505 277-2541 Email: tech-support@lternet.edu URL: http://www.lternet.edu
Contact: Individual: Information Manager Sevilleta LTER Physical Address: Delivery Address: 1 University of New Mexico City: Albuquerque Postal Code: 87131 Phone: US Phone: (505) 277-2109 Phone: (505) 277.5355 Email: data-use@sevilleta.unm.edu
Publisher: Individual: Information Manager Sevilleta LTER Physical Address: Delivery Address: 1 University of New Mexico City: Albuquerque Postal Code: 87131 Phone: US Phone: (505) 277-2109 Phone: (505) 277.5355 Email: data-use@sevilleta.unm.edu
Publication Place:	Sevilleta LTER
Method Step: Description: When the samples were collected: The samples were collected in winter, spring, summer, and fall, of each year.  Rabbit populations were sampled during a single night during each of these four seasons per year.  Dates of collection varied in some years, but generally the sampling was conducted in January, April, July, and October. Sampling Design: The rabbits were sampled along 21.5 miles of roadway that was broken up into four "legs" of varying lengths. Leg A:  Black Butte southward to Five Points (5.7 miles). Leg B:  Five Points eastward to the turnoff before Palo Duro Canyon (4.1 miles). Leg C:  Palo Duro turnoff northward to the old McKenzie Headquarters site (6.1 miles). Leg D:  McKenzie Headquarters site northwestward to Black Butte (5.6 miles). Measurement Techniques: The rabbit surveys were conducted at night using spotlights. Surveys began one hour after sunset, when no trace of sunlight or dusk remained.  Beginning in 1998, samples were taken only during full-moon periods. A pickup truck was driven slowly (8-10 miles per hour) along the road of the 21.5 mile circuit.  Two (or more) observers stood in the bed of the pickup truck, and scanned the left and right sides (respectively) of the road with spotlights, while the driver kept watch for rabbits directly in front in the road.  During 1992, the spotlights were Q-Beam 500,000 candlepower spotting lights, with both flood and spot settings (spot settings were used during the rabbit sampling).  From 1993 through 1996, Q-Beam spotlights with 1,000,000 candlepower were used.  In 1997, new spotlights with 3,000,000 candlepower were used; these lights were set permanently on "flood", but illuminated well at distances previously reached by the spot settings of the less-powerful spotlights.   In addition to the spotlights used by the standing observers in the bed of the pickup truck, two spotlights mounted on the pillar posts of the truck's cab were turned on and set for the roadsides ahead of the truck; these lights, coupled with the high-beam setting of the truck's headlights, illuminated the road in front of the truck for approximately 100 meters. When a rabbit was observed, one person's spotlight illuminated the spot at which the rabbit was first seen.  The second person's spotlight would track the rabbit, so that it was not counted twice.  A meter tape was walked out from the center of the truck bed (which equalled the center of the road) in a perpendicular direction from the road to the location at which the rabbit was first observed.  That distance was measured and recorded to the nearest meter. If a rabbit was observed in the middle of the road, the distance was recorded as zero.  Beginning in January, 2000, perpendicular distances to the rabbits were taken with a laser range finder, with accuracies of less than 1 meter (accuracies were tested before field use and confirmed to be <1m).  Generally, rabbits within 100 meters of the road could be seen relatively clearly with all three types of spotlights. Other data recorded included (1) the odometer reading in miles from the beginning of the sample at Black Butte (odometers were reset to zero at the start of the sample), (2) whether the rabbit was on the Left or Right side of the road, and (3) the species of rabbit.  In addition, incidental data were recorded on weather conditions, presence of clouds and moon, and the time at which the survey was begun, along with the times at which each Leg was begun and finished.  Finally, the names of the people on the sampling crew were recorded. Analytical Procedures: The perpendicular distance data were entered into Program DISTANCE to estimate the total density of rabbits in the study area. Values were computed as numbers of individuals per square kilometer In the analyses, if there were sufficient numbers of rabbits (>10 per leg), the difference legs were analyzed separately, and the resulting mean densities were estimated by averaging the four leg estimates.  In the results tables below, these instances are indicated by the category, "MEAN".  If sample sizes were too small to estimate the four legs separately, then all the rabbit observations were pooled together, and a density estimate for the entire 21.5 mile survey was calculated. These results are indicated by the category, "ALL".
Quality Control: Description: The program DISTANCE command codes were as follows: Options; Title='SEVILLETA RABBIT DENSITIES'; Type=Line; Length/Units='Miles'; Area/Units='Hectares'; Distance=Perp/Measure='Meters'/Exact; Object=Single; End; Data; Stratum/label='DATE ENTERED HERE'; Sample=1/Label='ALL LEGS, DATE ENTERED HERE'/Effort=21.5; DISTANCE DATA ENTERED HERE, SEPARATED BY COMMAS; End; Estimate; Est /key=uniform /adj=cosine  /select=sequential /criterion=AIC /monotone=weak; Est /key=uniform /adj=hermite /select=sequential /criterion=AIC /monotone=weak; Est /key=hnormal /adj=cosine  /select=sequential /criterion=AIC /monotone=weak; Est /key=hnormal /adj=hermite /select=sequential /criterion=AIC /monotone=weak; Pick=AIC; Density by sample; End;
Data Table: Entity Name: sev113_rabbitdens_20040226 Entity Description: Data for SEV113 Object Name: sev113_rabbitdens_20040226.txt Size: 2058 Data Format: Text Format: Number of Header Lines: 1 Record Delimiter: \r\n Attribute Orientation: column Simple Delimited: Field Delimiter: , Distribution: Online: URL: https://pasta.lternet.edu/package/data/eml/knb-lter-sev/113/119299/4331627b0b4744799a51b758dca11046 Coverage: Temporal Coverage: Date Range: Begin Date: Calendar Date: 1992-01-20 End Date: Calendar Date: 2002-07-23 Attribute List: Attribute Name: day Attribute Label: day Attribute Definition: The day of the month in which data were collected. Storage Type: date Measurement Scale: Datetime: Format String: DD Attribute Name: month Attribute Label: month Attribute Definition: The month in which data were collected. Storage Type: date Measurement Scale: Datetime: Format String: MM Attribute Name: year Attribute Label: year Attribute Definition: The year in which data was collected. Storage Type: date Measurement Scale: Datetime: Format String: YYYY Attribute Name: #legs Attribute Label: #legs Attribute Definition: Number of roadway sections sampled from. Storage Type: string Measurement Scale: Nominal: Non Numeric Domain: Text Domain: Definition: Number of roadway sections sampled from. Attribute Name: #observed Attribute Label: #observed Attribute Definition: Number of rabbits observed. Storage Type: string Measurement Scale: Nominal: Non Numeric Domain: Text Domain: Definition: Number of rabbits observed. Attribute Name: density_estimate Attribute Label: density_estimate Attribute Definition: Estimate of density of rabbits. Measurement Scale: Ratio: Unit: Custom Unit: numberPerHectare Numeric Domain: Number Type: real Attribute Name: s.d. Attribute Label: s.d. Attribute Definition: Standard error. Storage Type: string Measurement Scale: Nominal: Non Numeric Domain: Text Domain: Definition: Standard error. Attribute Name: estimator_used Attribute Label: estimator_used Attribute Definition: Model name. Storage Type: string Measurement Scale: Nominal: Non Numeric Domain: Text Domain: Definition: Model name.