mammals

Gunnison's Prairie Dog Restoration Experiment (GPDREx): Small Mammal Mark-Recapture Population Assessment within Grasslands at the Sevilleta National Widlife Refuge, New Mexico (2013-2014)

Abstract: 

Prairie dogs (Cynomys spp.) are burrowing rodents considered to be ecosystem engineers and keystone species of the central grasslands of North America. Yet, prairie dog populations have declined by an estimated 98% throughout their historic range. This dramatic decline has resulted in the widespread loss of their important ecological role throughout this grassland system. The 92,060 ha Sevilleta NWR in central New Mexico includes more than 54,000 ha of native grassland. Gunnison’s prairie dogs (C. gunnisoni) were reported to occupy ~15,000 ha of what is now the SNWR during the 1960’s, prior to their systematic eradication. In 2010, we collaborated with local agencies and conservation organizations to restore the functional role of prairie dogs to the grassland system. Gunnison’s prairie dogs were reintroduced to a site that was occupied by prairie dogs 40 years ago.  This work is part of a larger, long-term study where we are studying the ecological effects of prairie dogs as they re-colonize the grassland ecosystem. With this project, we would like to further investigate the impact that Gunnison’s prairie dogs have on the landscape.  Gunnison’s prairie dog monitoring data has been collected from the beginning of the reintroduction project, but little information has been collected on how grassland species respond to the sudden presence of prairie dogs on the refuge.

This project will help determine if the prairie dog reintroduction has had positive impacts on the grassland ecosystem.  Prairie dogs benefit grasslands in many ways, but their role as ecosystem engineers directly impacts other species by creating new habitat that would not be present without prairie dogs.  We have documented physical landscape changes, but we have not specifically documented benefits to other grassland species.  This work will help determine if the reintroduced prairie dog populations on Sevilleta NWR are now acting as a keystone species in a grassland ecosystem by monitoring small mammal populations to see if species richness, diversity, and density are different on prairie dog colonized areas versus non-colonized areas.

Data set ID: 

239

Core Areas: 

Additional Project roles: 

275

Keywords: 

Methods: 

Trapping Location and Design:

Trapping will be done on the 16ha Prairie Dog Relocation Study Plots.  There are 4 of them- A, B, C, and D.  Each plot will have 169 traps placed in a grid covering 9 hectares. Using the vegetation quad map, there will be a trap placed at 1 meter to the north at each of the following vegetation plots 11-17, 20-26, 29-35, 38-44, 47-53, 56-62, 65-71.  This accounts for 49 of the traps.  There will also be a trap placed in between each veg plot, with rows running North/South, which accounts for 42 more of the traps.  Then making a complete row in between the North/South vegetation quad rows, will account for the remaining 78 traps. To locate the veg plots, each are marked with a rebar and short white PVC.  There is a numbered tag on each PVC corresponding to the map.

Flag each trap with a numbered pin flag to designate trap numbers.   This is important in ensuring that all traps are checked and closed each day.

Trapping Periods:

Trapping period will be one plot a week for 4 nights.

Trapping Procedure:

The traps are set each evening for four nights.  This entails setting and baiting the traps at a given locality on Monday afternoon, then checking the traps at dawn on Tuesday (night 1), Wednesday (night 2), Thursday (night 3), and Friday (night 4). Each trap is baited with a handful of steamed, crimped oats tossed into the trap after it is placed on the ground; a few oats are left outside the trap entrance to entice passers-by.  The ground needs to be smoothed out with a foot to make sure that the trap is level and not unbalanced.  

Each morning, traps are checked as follows:  the worker walks up and down the transects and closes open traps as you go along.  Traps are not reopened until the late afternoon/early evening, at which time additional bait is also put in.  When a closed trap is encountered, it is first checked to see if an animal is present by carefully and just slightly opening the door of the trap and looking inside.  Be aware that kangaroo rats can jump out while doing this, so use caution. Sometimes, although a trap may appear empty, a tiny rodent may be hiding under the treadle (especially in the large traps).  To check for this, one must reach into the trap and lightly push down the treadle.  If the treadle will not go down, there is likely a mouse underneath.  If no animal is in the trap, the trap is left closed until the afternoon. If a trap has an animal, the worker processes the animal at the stake and takes the relevant data.  While checking for animals on Friday morning (night four), traps are picked up, emptied of seed, and returned to storage boxes, ready for placement at another locality the following week.  Importantly, traps MUST BE counted as they are placed into storage boxes in order to insure that no traps (or animals) are left on the plot.  If rain falls on the baited traps, they may require cleaning and drying back at the field station before storage or use the following week.

Animal Processing:

Removing rodents from trap

For each capture, the trap number is recorded first.  Next, a given animal is shaken from the trap into a plastic gallon ziploc bag.  This is accomplished by wrapping the opening of the ziploc bag over the door end of the trap. Make sure that they bag is tight so the rodent can’t squeeze out between the bag and the trap.  Open the front door through the bag and lock open.  Roll the trap upside down and swing it in an arc downward.  As soon at the rodent enters the bag, close the bag off with your hand so the rodent cannot reenter the trap.  With kangaroo rats, you often do not need to shake the trap to get the animals out.  Instead, put the Ziploc bag on trap as normal and open trap door, but hold the trap angled upward instead of down and the rodent should come out on its own.  Hold tight on the bag though because sometimes they come out rather quickly.

If a trap is triggered, but appears empty, don’t assume there is no animal in trap.  Small species such as pocket mice can hide under the treadle.  Make sure and lightly press down on the treadle to make sure it goes all of the way down.  If not then there is most likely a rodent under treadle.  You can also open up the back door to look under treadle, but use caution as to not let rodent escape.

If another animal (lizard, bird, rabbit, prairie dog) is caught in the trap, they can simply be released.  However, make sure and mark on data sheet that the trap was closed due to bird/lizard/rabbit.  If you do find a trap that was triggered by wind or large animal and is in fact empty, make sure and mark on the datasheet that that trap number was triggered but empty.

Handling and Processing rodents

In the bag, the processor positions the rodent with its head in the corner of the bag.  Hold its head down with one hand from the outside of the bag, pressing gently on the back of the skull.  Then reach in the bag with the other hand and grasp the animal with the thumb and forefingers by the loose skin around the back of the neck and shoulders, and then remove it for inspection. 

First off check to see if the rodent is tagged or marked.  If it is then you will mark that individual as a recapture on data sheet.  After recording the ear tag number or other marking and the species of animal, it can be released.  If it is not marked, then it will need to be marked and processed.

Dipodomys spp, Onychomys spp, Neotoma spp, Peromyscus spp, and any other large species you may catch will be uniquely marked with one ear tag.  Ear tags should be placed at the very base of the ear on its interior edge (or the front of the ear).  Putting it on the external side or back of the ear allows the rodent to rip the ear tag off more easily, by scratching at it with its hind legs. 

Other species such as, Perognathus spp, Spermophilus spp, and other small rodents that have too small of ears to place an ear tag, will be marked with sequential individual numbers on their chest, using permanent markers.  A different color must be used for each night (blue for 1st night, black for 2nd night, and red for 3rd night).  Small rodents do not need to be marked the 4th night,  but large rodents do need to be ear tagged.  Start with number 1 and increase as necessary for catches.

Next, each animal is identified to species, sexed, and aged.  Specific measurements are taken only for those genera which required them for species identification:

            Peromyscus: Total length, tail, foot, ear;

            Onychomys:  Total length, tail, foot.

            Perognathus, and Reithrodontomys: Total length, tail.

All measurements are taken to the nearest millimeter using a plastic ruler.  The species is recorded by a 4-letter code that represents the first 2 letters of the genus and the first 2 letters of the species.

Sex and reproductive status is then determined by examination of the genitalia (lactating/vaginal/pregnant/scrotal).  Look for enlarged scrotum, enlarged nipples, or an enlarged vaginal opening.  If none of these are apparent, then the rodent is non-reproductive. Females will still have visible nipples when non-reproductive.

ADULT MALES reproductive status:

-Scrotal (ST): the scrotum can be fully enlarged or partially enlarged.

- Non-reproductive (N)

ADULT FEMALES reproductive status:

-Vaginal (V): in estrus; vagina is obviously swollen and looks large and puckered, vaginal plug can be present or absent

-Pregnant (P):  heavier weight, can palpate babies

-Lactating (L): nipples (at least one) reddish and/or enlarged

-Non-reproductive (N)

Before releasing the individual, it is then weighed to the nearest gram, using a Pesola scale clipped to the base of the animal’s tail.   Larger animals can easily get off of scale so it is easier to put them back in the bag and weigh them inside the bag.  Make sure and weigh bag after rodent is released and subtract from first weight to get actual weight of rodent.

Animals which perished during captivity on plots are noted in the comments on field data sheets as 'D.I.T' (Dead In Trap).

Data sources: 

sev239_REUrodenttrapping_20140605.txt

Additional information: 

This data is collected each summer, starting in 2013, by an student in the Sevilleta LTER Research Experience for Undergraduates Summer Program.  Ear tagging started taking place in the summer of 2014.

Data Collector History

Ty Werdel 2013

Betsy Black & Andrew Velselka 2014

Gunnison's Prairie Dog Restoration Experiment (GPDREx): Population Dynamics within Grasslands at the Sevilleta National Widlife Refuge, New Mexico

Abstract: 

Prairie dogs (Cynomys spp.) are burrowing rodents considered to be ecosystem engineers and keystone species of the central grasslands of North America. Yet, prairie dog populations have declined by an estimated 98% throughout their historic range. This dramatic decline has resulted in the widespread loss of their important ecological role throughout this grassland system. The 92,060 ha Sevilleta NWR in central New Mexico includes more than 54,000 ha of native grassland. Gunnison’s prairie dogs (C. gunnisoni) were reported to occupy ~15,000 ha of what is now the SNWR during the 1960’s, prior to their systematic eradication. In 2010, we collaborated with local agencies and conservation organizations to restore the functional role of prairie dogs to the grassland system. Gunnison’s prairie dogs were reintroduced to a site that was occupied by prairie dogs 40 years ago.  This work is part of a larger, long-term study where we are studying the ecological effects of prairie dogs as they re-colonize the grassland ecosystem.

Data set ID: 

236

Additional Project roles: 

401

Core Areas: 

Keywords: 

Methods: 

Experimental Design

Four replicate paired 16 ha plots were established in spring 2010. Each pair consists of a treatment plot with prairie dogs (reintroduced), which are plots B and D and a control plot with no prairie dogs (plots A and C). The closest distance between adjacent plots, either within a block or between blocks, is 200 m (Figure 1). The treatment and control within each pair were randomly assigned. Each plot is a 400x400 m on 9x9 grid array with systematically located sample locations for 81 vegetation quadrats. There are also 4 more plots, E and H are control plots and F and G are treatment plots. F and G have been equipped with artificial burrows and are release sites. However, E and H were not set up to do vegetation quads.

Trapping Period

Prairie dogs will be sampled using capture-recapture methods in the summer (3rd week of June) each year and spring (last week of March) and fall when possible.

Pre-baiting Procedure

Set 150 traps within each 300m x 300m trapping area. Place traps in pairs near active burrows at least 4 days prior to trapping. At this time trap doors should be wired open (make certain all traps are properly wired open) with bait trailing from the outside into the back of (or through) the trap. Traps should be baited with sweet feed. Make sure that all traps are functioning properly by testing the trap door sensitivity and adjusting with pliers if needed. Pre-bait traps every morning for 3 days total. All pairs of traps should be numbered with one pin flag for each pair (1-75). All trap pairs should also be GPSed by their number and have maps made for ease of locating traps during trapping.

Trapping Procedures

On the morning of the first trapping day, well before sunrise, the wire should be removed from the traps and the traps then set and baited to capture animals. This can also be done the day before trapping begins. Prairie dogs should be trapped for 3 consecutive mornings.Each morning of trapping, make sure that the traps are all opened well before sunrise, so animals are not disturbed by human activity. This is very important. Traps should only be left opened during the early morning period, until about 10:00 or 11:00 am, depending on the weather conditions and time of year. Prairie dog activity declines by 10:00-11:00, so even if the weather conditions are fine for continued trapping, trap success after this time will decline. Traps should be collected by around 9:00 am, depending on the weather conditions and time of year, and all trapped animals should be brought to a common processing station. The team walks the plot to make sure and check every trap for dogs. As dogs are found trapped, a piece of masking tape is attached to the front of the trap, labeled with the trap number so that that animal can be released where it was trapped. Animals at the processing site should be kept at all times in the shade and carrots should be given to provide moisture during the heat and stress. Once animals have been processed they should be released into their burrow, at the location of their capture. All traps should then be closed for the day. To make sure all are closed, one person should close all the traps from one of the plots and mark the number on the GPS sheet to note the trap has been closed. This can also be done as a team effort, but traps need to be checked twice to make sure they are all closed.

Data sources: 

sev236_pdog_captures_20150630.txt

Gunnison's Prairie Dog Restoration Experiment (GPDREx): Vegetation Cover Data from the Sevilleta National Wildlife Refuge, New Mexico (2011 - present)

Abstract: 

Prairie dogs (Cynomys spp.) are burrowing rodents considered to be ecosystem engineers and keystone species of the central grasslands of North America. Yet, prairie dog populations have declined by an estimated 98% throughout their historic range. This dramatic decline has resulted in the widespread loss of their important ecological role throughout this grassland system. The 92,060 ha Sevilleta NWR in central New Mexico includes more than 54,000 ha of native grassland. Gunnison’s prairie dogs (C. gunnisoni) were reported to occupy ~15,000 ha of what is now the SNWR during the 1960’s, prior to their systematic eradication. In 2010, we collaborated with local agencies and conservation organizations to restore the functional role of prairie dogs to the grassland system. Gunnison’s prairie dogs were reintroduced to a site that was occupied by prairie dogs 40 years ago.  This work is part of a larger, long-term study where we are studying the ecological effects of prairie dogs as they re-colonize the grassland ecosystem.

Data set ID: 

238

Core Areas: 

Additional Project roles: 

486
487
488
489
490

Keywords: 

Methods: 

Experimental Design

Two replicate paired 16 ha plots were established in spring 2010. Each pair consists of a treatment plot with prairie dogs (reintroduced), which are plots B and D and a control plot with no prairie dogs (plots A and C).  There are 4 other plots (E,F,G, and H) but they are not set up to do vegetation sampling. 

Sampling Periods

 Baseline vegetation sampling occurred at the end of April 2010. A second sampling was done at the end of September 2011.  There was no other vegetation sampling until September 2013, at which time it will be collected consistently every spring and fall. 

Field Procedures 

Percent live plant canopy cover and height of live foliage of all plant species are measured using 0.25 m2 vegetation sampling quadrats at the end of the growing season each spring (late April) and late summer (early September).  The 50x50 cm vegetation measurement frame has a string grid which partitions the frame into 25, 10x10 cm squares. One quarter of a 10x10 cm grid cell equals 1% cover. Therefore each 10x10 cm cell has a 4% cover value. Vegetation measurements range from 0.1 to 100%. A cover of 0.1 represents a plant species trace occurrence on the quad. The next smallest measurement is 1%, or ¼ of a 10x10 cm grid cell. Cover is measured to the nearest 1% for 1-10% cover and to the nearest 5% for 10-100% cover. Total cover for a particular plant species is measured by counting the number of 10x10 cm cells occupied by the foliage canopy, multiplying that value by 4 and rounding to the nearest 5% for total cover greater than 10%. Typical maximum plant canopy height for each species is also measured to the nearest centimeter.

Data sources: 

sev238_pdogvegcover_20161017.csv

Additional information: 

More information about who is involved with the samples/data:

Terri Koontz 2010

Amaris Swann 2011

John Mulhouse 2011

Stephanie Baker 2011-present

Megan McClung 2013-present

Chandra Tucker 2014-present

Study Site Information: 

The SevLTER Prairie Dog Project 16 ha study plots are located east of the Blue Grama Core site at the foothill of the Los Pinos Mountains and along Test Well Road. It is a grassland dominated by blue grama grass, with associated grass species consisting of black grama, galleta, purple three-awn, sand muhly, and dropseed. Yucca and Cholla cactus are the dominant shrubs at the site.

Gunnison's Prairie Dog Relocation Project: Population Dynamics within Grasslands at the Sevilleta National Widlife Refuge, New Mexico (2005-2014)

Abstract: 

The Sevilleta Gunnison’s Prairie Dog (Cynomys gunnisoni) Restoration project examines keystone consumer (herbivore) effects on grassland in concert with ecological restoration of a “species of greatest conservation need in New Mexico” (NMG&F Comprehensive Wildlife Conservation Strategy, 2007). SevLTER partners directly with Sevilleta National Wildlife Refuge, New Mexico Game and Fish, USFS Rocky Mountain Research Station and non-profit Prairie Dog Pals on this ambitious effort to re-establish Gunnison’s prairie dogs to blue grama dominated (Bouteloua gracilis) Great Plains grassland at the foothills of the Los Pinos Mountains on Sevilleta. While engaged in wildlife management aimed at translocation of approximately 3000 individual prairie dogs, ultimately establishing 5-6 colonies over a 500 ha area, SevLTER is focusing resources on monitoring population dynamics of reintroduced prairie dogs and their effects on vegetation production and diversity, soil disturbance and grasshopper community composition. In this experiment, prairie dogs act as the treatment on a grassland site where the species was extirpated 40 years ago. The long term nature of the project lies in the course of re-establishing prairie dogs combined with the ultimate research goal of describing the functional role of Gunnison’s prairie dogs in an arid grassland ecosystem: first we are challenged to develop and document an economical and efficient management strategy which maximizes reintroduction success and colony survival; second we are tasked with monitoring prairie dog dynamics and their effects on the grassland throughout re-establishment and into a future state, when presumably management intervention will have subsided and we characterize the ecosystem as ‘restored’ – both in the face of highly variable abiotic inputs such as precipitation and temperature and biotic impacts such as predation.

Data set ID: 

257

Core Areas: 

Keywords: 

Data sources: 

sev257_pdog_trapping_20140116

Methods: 

Sampling Period

Prairie dogs will be sampled using mark-re-sight methods in the spring (last week of March) and summer (3rd week of June) each year.  The justification for this sampling period is to understand overwinter survival and offspring recruitment.

Mark Re-sight Methodology

Prebaiting and Observation Towers

Prior to any trapping, traps in the field are checked to make sure all wooden covers are in place, if not, traps should be repaired as needed.  Set 100 traps within each 100m x 100m trapping area.  Place traps near active burrows 4 days prior to trapping.  At this time trap doors are wired open (make certain all traps are properly wired open) with bait trailing from the outside into the back of (or through) the trap. Traps are baited with sweet feed. Make sure that all traps are functioning properly by testing the trap door sensitivity and adjusting with pliers if needed. Pre-bait traps every morning for 3 sequential days total. All traps should be GPSed and have an adjacent numbered flag and tape with a corresponding number located on the trap. 

Trapping

On the morning of the fourth day, well before sunrise, the wires are removed from the traps and the traps then set and baited to capture animals. The traps are all opened well before sunrise, so animals are not disturbed by human activity.  This is very important.  Prairie dogs are trapped for 3 consecutive mornings.  Traps are only left opened during the early morning period, until about 10:00 or 11:00 am, depending on the weather conditions and time of year.  Prairie dog activity declines by 10:00-11:00, so even if the weather conditions are fine for continued trapping, trap success after this time will decline dramatically.  Traps are collected by around 9:00 am, depending on the weather conditions and time of year, and all trapped animals are brought to a common processing station. At the processing station the trap location, ear tag number, sex, weight, and age of the animal are recorded. It is indicated if the animal is new or a re-capture during this trapping period.  If no ear tags are present, new ear tags are clipped to both ears, and the numbers recorded. If one ear tag is missing, another is added to the ear with no tag, and the number recorded. All animals are marked with Nyanzol black dye.  For our purposes, it is not necessary to mark each animal with numbers.  The goal is to make sure each animal has a clear black mark on its back. Animals at the processing site are kept at all times in the shade and carrots should be given to provide moisture during the heat and stress.  Once animals have been processed they are released into their burrow, at the location of their capture. All traps are closed for the day.  To make sure all are closed, one person  closes all the traps from one of the plots and mark the number on the GPS sheet to note the trap has been closed.

Additional information: 

Additional Study Area Information

Study Area Name: Prairie Dog Town

Study Area Location: The study area is about 655 ha (~2.5 sq mi) in size and approximately1 km due west from the foothills of the Los Pinos Mountains. The study is also just north of the Blue Grama Core Site.

Elevation: 1670 m

Soils: sandy loam and sandy clay loam

Site history: historically large prairie dog colonies inhabited the study area

Gunnison’s Prairie Dog Use of Resource Pulses in a Chihuahuan Desert Grassland at the Sevilleta National Wildlife Refuge, New Mexico: Re-sight Scan Data

Abstract: 

Seasonal environments experience cyclical or unpredictable pulses in plant growth that provide important resources for animal populations, and may affect the diversity and persistence of animal communities that utilize these resources. The timing of breeding cycles and other biological activities must be compatible with the availability of critical resources for animal species to exploit these resource pulses; failure to match animal needs with available energy can cause population declines. Adult Gunnison’s prairie dogs emerge from hibernation and breed in early spring, when plant growth is linked to cool-season precipitation and is primarily represented by the more nutritious and digestible plants that utilize the C3 photosynthetic pathway. In contrast, summer rainfall stimulates growth of less nutritious plants using the C4 photosynthetic pathway. Prairie dogs should therefore produce young during times of increased productivity from C3 plants, while pre-hibernation accumulation of body fat should rely more heavily upon C4 plants.  If seasonal availability of high-quality food sources is important to Gunnison’s prairie dog population growth, projected changes in climate that alter the intensity or timing of these resource pulses could result in loss or decline of prairie dog populations.  This project will test the hypothesis that population characteristics of Gunnison's prairie dog, an imperiled grassland herbivore, are associated with climate-based influences on pulses of plant growth.

Data set ID: 

242

Core Areas: 

Additional Project roles: 

40
41

Keywords: 

Methods: 

Gunnison’s prairie dogs will be monitored at 6 colonies, with 3 colonies each occurring with the range of prairie and montane populations. Colonies for study within the prairie populations occur at Sevilleta National Wildlife Refuge (n = 3 prairie populations) and at Vermejo Park Ranch (n = 3 montane populations).  Live-trapping of prairie dogs will be conducted during 3 periods of the active seasons—following emergence (April), after juveniles have risen to the surface (mid-to-late June), and pre-immergence (beginning in August).  Trapping will occur for 3-day periods, following pre-baiting with open traps.  At capture, sex and body mass of each individual will be recorded.  Blood and subcutaneous body fat samples will be collected nondestructively for analysis of isotopic composition.  Prairie dogs will be marked with dye, and released on site immediately following processing.  After trapping periods at each site have concluded, population counts will be conducted during 2-3 re-sighting (or recapture) periods for each prairie dog colony.  Resighting observation periods will be ~3 hours in length, and consist of 2-6 systematic scans of the entire colony, beginning and ending from marked points outside of the colony boundary.  During each observation period, prairie dogs will be counted, recorded as marked or unmarked, and location on the colony noted.  

Vegetation cover and composition measurements will be collected (or obtained at Sevilleta, where such data is already being collected) during pre- and post-monsoon periods of the active season.  Total cover will be measured by plant species (or to genus if species is indeterminable). Total cover will be measured at 12 grid points per colony using Daubenmire frames (0.5 m x 0.5 m), and at 12 grid locations 200-800 m outside of each colony boundary.  Adjacent to each Daubenmire frame, a 20 cm x 30 cm sample of vegetation will be clipped and dried for determination of volumetric moisture content of vegetation.  

Primary productivity variables (cover, moisture content) will be tested for correlations to individual and population-level condition indicators in prairie dogs.  Carbon isotope ratios (δ13C) from prairie dog blood and fat samples will be analyzed on a continuous flow isotope ratio mass spectrometer.  The relative contribution of C3 and C4 plants to the diet of each individual will be determined based upon δ13C ratios for C3 and C4 plants in the study area and a 2-endpiont mixing model, and will be calculated for each individual animal, population and season.  Population estimates will be calculated using mark-resight estimates, and compared to maximum above-ground counts.  The influence of resource pulses on prairie dog population parameters will be tested by comparing the vegetation cover, moisture content, and ratio of total C3:C4 plant cover to the ratio of C3:C4 plants in prairie dog diets, population estimates, and juvenile:adult ratios as an index to population recruitment.   

Instrumentation: 

*Instrument Name: Continuous flow isotope ratio mass spectrometer

*Manufacturer: Thermo-Finnigan IRMS  Delta Plus 

*Instrument Name: Elemental Analyzer

*Manufacturer: Costech

*Model Number: ECS4010

Additional information: 

Other Field Crew Members: Talbot, William; Duran, Ricardo; Gilbert, Eliza; Donovan, Michael; Nichols, Erv; Sevilleta LTER prairie dog field crew led by Koontz, Terri; Sevilleta NWR prairie dog field crew led by Erz, Jon.

Tissue samples are analyzed for stable carbon isotope ratios in stable isotope laboratory operated by Dr. Zachary Sharp and Dr. Nicu-Viorel Atudorei of the Department of Earth and Planetary Sciences, University of New Mexico.

Keystone species have large impacts on community and ecosystem properties, and create important ecological interactions with other species.  Prairie dogs (Cynomys spp.) and banner-tailed kangaroo rats (Dipodomys spectabilis) are considered keystone species of grassland ecosystems, and create a mosaic of unique habitats on the landscape.

Our objective was to evaluate the effects of kangaroo rat mounds on species diversity and composition at a semiarid-arid grassland ecotone. We expected that source populations of plants occurring on kangaroo rat mounds have important influences on species composition of vegetation at the landscape scale, and that these influences differ by grassland type.

Gunnison's Prairie Dog Use of Resource Pulses in a Chihuahuan Desert Grassland at the Sevilleta National Wildlife Refuge, New Mexico: Capture Data

Abstract: 

Seasonal environments experience cyclical or unpredictable pulses in plant growth that provide important resources for animal populations, and may affect the diversity and persistence of animal communities that utilize these resources. The timing of breeding cycles and other biological activities must be compatible with the availability of critical resources for animal species to exploit these resource pulses; failure to match animal needs with available energy can cause population declines. Adult Gunnison’s prairie dogs emerge from hibernation and breed in early spring, when plant growth is linked to cool-season precipitation and is primarily represented by the more nutritious and digestible plants that utilize the C3 photosynthetic pathway. In contrast, summer rainfall stimulates growth of less nutritious plants using the C4 photosynthetic pathway. Prairie dogs should therefore produce young during times of increased productivity from C3 plants, while pre-hibernation accumulation of body fat should rely more heavily upon C4 plants. If seasonal availability of high-quality food sources is important to Gunnison’s prairie dog population growth, projected changes in climate that alter the intensity or timing of these resource pulses could result in loss or decline of prairie dog populations. This project will test the hypothesis that population characteristics of Gunnison's prairie dog, an imperiled grassland herbivore, are associated with climate-based influences on pulses of plant growth.

Data set ID: 

241

Core Areas: 

Additional Project roles: 

37
38
39

Keywords: 

Methods: 

Gunnison’s prairie dogs will be monitored at 6 colonies, with 3 colonies each occurring with the range of prairie and montane populations. Colonies for study within the prairie populations occur at Sevilleta National Wildlife Refuge (n = 3 prairie populations) and at Vermejo Park Ranch (n = 3 montane populations). Live-trapping of prairie dogs will be conducted during 3 periods of the active seasons—following emergence (April), after juveniles have risen to the surface (mid-to-late June), and pre-immergence (beginning in August). Trapping will occur for 3-day periods, following pre-baiting with open traps. At capture, sex and body mass of each individual will be recorded. Blood and subcutaneous body fat samples will be collected nondestructively for analysis of isotopic composition. Prairie dogs will be marked with dye, and released on site immediately following processing. After trapping periods at each site have concluded, population counts will be conducted during 2-3 re-sighting (or recapture) periods for each prairie dog colony. Resighting observation periods will be ~3 hours in length, and consist of 2-6 systematic scans of the entire colony, beginning and ending from marked points outside of the colony boundary. During each observation period, prairie dogs will be counted, recorded as marked or unmarked, and location on the colony noted. Vegetation cover and composition measurements will be collected (or obtained at Sevilleta, where such data is already being collected) during pre- and post-monsoon periods of the active season. Total cover will be measured by plant species (or to genus if species is indeterminable). Total cover will be measured at 12 grid points per colony using Daubenmire frames (0.5 m x 0.5 m), and at 12 grid locations 200-800 m outside of each colony boundary. Adjacent to each Daubenmire frame, a 20 cm x 30 cm sample of vegetation will be clipped and dried for determination of volumetric moisture content of vegetation. Primary productivity variables (cover, moisture content) will be tested for correlations to individual and population-level condition indicators in prairie dogs. Carbon isotope ratios (δ13C) from prairie dog blood and fat samples will be analyzed on a continuous flow isotope ratio mass spectrometer. The relative contribution of C3 and C4 plants to the diet of each individual will be determined based upon δ13C ratios for C3 and C4 plants in the study area and a 2-endpiont mixing model, and will be calculated for each individual animal, population and season. Population estimates will be calculated using mark-resight estimates, and compared to maximum above-ground counts. The influence of resource pulses on prairie dog population parameters will be tested by comparing the vegetation cover, moisture content, and ratio of total C3:C4 plant cover to the ratio of C3:C4 plants in prairie dog diets, population estimates, and juvenile:adult ratios as an index to population recruitment.

Instrumentation: 

Instrument Name: Continuous flow isotope ratio mass spectrometer Manufacturer: Thermo-Finnigan IRMS Delta Plus Model Number: Instrument Name: Elemental Analyzer Manufacturer: Costech Model Number: ECS4010

Additional information: 

Field Crew: Hayes, Chuck; Talbot, William; Duran, Ricardo; Gilbert, Eliza; Donovan, Michael; Nichols, Erv; Sevilleta LTER prairie dog field crew led by Koontz, Terri; Sevilleta NWR prairie dog field crew led by Erz, Jon.

Gunnison's Prairie Dog Relocation Project: Vegetation Standing Crop Data from the Sevilleta National Wildlife Refuge, New Mexico (2005-2011)

Abstract: 

Grasslands are among the most imperiled ecosystems in the world where the loss of native species is
a consequence of agriculture and desertification. In North America, 90% of the grassland has been
converted to cropland where vast areas are now desertified. North America's most iconic grassland
herbivores, bison and prairie dogs, are now extinct throughout most of their historic range. This
study measures the standing crop of plant vegetation (perennial and annual combined) for the year
on areas occupied and not occupied by Gunnison's prairie dogs on the Sevilleta National Wildlife
Refuge (NWR).

Core Areas: 

Data set ID: 

213

Additional Project roles: 

196

Keywords: 

Data sources: 

sev213_pdogstandcrop_20160309.csv

Methods: 

Experimental design

Three replicates of two treatments: 1)plots where prairie dogs have been reintroduced and 2)control plots.

Sampling design

Each 100 x 100m plot contains 36 sample units (quads) that are 20m apart in a 6 x 6 grid. These quads are numbered in a zig zag pattern starting in the NE corner of the plot where the first six quads go north to south, the next six plots that are west of the first quads go south to north,  and so on for the remaining quads on the plot. These quads are marked by a numbered rebar stake. Standing crop samples are taken in the 16 most inner stakes near the rebar stake, but not where vegetation quads are located.

Field/laboratory proceducres

Total above ground annual plant standing crop is collected each fall during peak growth from 16 Daubenmier (0.25m x 0.50m) frame quads. All vegetation rooted in the quad are clipped to the soil surface and placed in brown paper bags. Samples are dried at 55 degrees Celsius in an oven for 48 hours then weighed.

Maintenance: 

Metadata put into access 26 May 2009. tlk. checked for obvious errors, 11 January 2010 tlk. If you find any errors or have questions, please contact the information manager.

Quality Assurance: 

Data were entered from data sheets into an excel spreadsheet. Data were then checked against data sheets following entry.

Additional information: 

More information about who is involved with the samples/data:

Mike Friggens 1999-September 2001
Karen Wetherill February 7, 2000-Augst 2009
Terri Koontz February 2000-August 2003 August 2006-Present
Shana Pennington February 2000-August 2000
Heather Simpson August 2000-August 2002
Chris Roberts September 2001-August 2002
Caleb Hickman September 9, 2002-November 15, 2004
Seth Munson September 9, 2002-June 2004
Maya Kapoor August 9, 2003-January 21, 2005
Tessa Edelen August 15, 2004-August 15, 2005
Charity Hall January 31, 2005-January 3, 2006
Yang Xia January 31, 2005-Present
Michell Thomey September 3, 2005-August 2008
Jay McLeod January 2006-August 2006
Amaris Swann August 25, 2008-Present
John Mulhouse August 2009-Present
Amanda Boutz August 2009-Present

Additional Study Area Information

Study Area Name: Prairie Dog Town

Study Area Location: The study area is about 655 ha (~2.5 sq mi) in size and approximately 1 km due west from the foothills of the Los Pinos Mountains. The study is also just north of the Blue Grama Core Site.

Elevation: 1670 m

Soils: sandy loam and sandy clay loam

Site history: historically large prairie dog colonies inhabited the study area.

Coyote Scat Surveys in Chihuahuan Desert Grassland and Shrubland Sites, Spring, Summer and Fall at the Sevilleta National Wildlife Refuge, New Mexico (2008-2009)

Abstract: 

This data set contains information regarding carnivore scat surveys that were performed at sites in grama grassland and both creosote and mesquite shrubland habitats at the Sevilleta NWR. A total of nine surveys were carried out along road-based transects, each of which is a mile long, during one season in 2008 (June-July) and three seasons in 2009: spring (April-May), summer (July-August), and fall (October-November). There were 10 transects in grassland areas and 10 in shrubland areas in 2008. All 20 transects, as well as two additional transects in grassland areas, were surveyed in 2009. For more information on the structure of the vegetation surrounding these road based transects, see the "Vegetation surveys in grassland and shrubland sites that are associated with coyote scat surveys at the Sevilleta NWR, 2008-2009" data set. Scat samples were identified in the field and collected for genetic and stable carbon isotope analysis. Field recorded variables include: scat freshness, maximum diameter, length, and GPS coordinates, as well as the field-based species identification for the sample. Information on the lab based species and individual identification results are also presented.

This data was collected in order to obtain information on the size and feeding ecology of the coyote populations in grassland vs. shrubland habitats in three seasons (spring, summer and fall) and two years (2008 and 2009) at the Sevilleta NWR. A mark recapture analysis can be performed on the data from 2009 since two surveys were carried out for each scat transect in each of the three seasons and coyote scats were run through a genetic analysis to determine individual identity of the coyotes. A rough assessment of coyote habitat use can also be performed using the individual identity and coyote scat location information. Future isotope analysis will indicate whether the base of the food chain is C4 (grass) vs. C3 (shrubs) plants in grassland vs. shrubland habitats in each of the three seasons (spring (pre-monsoon), summer (monsoon) and fall (post monsoon)) and in each of two years (2008 and 2009).

Data set ID: 

220

Core Areas: 

Additional Project roles: 

373
374
375

Keywords: 

Data sources: 

sev220_coyotescatsurvey_20150618.csv

Methods: 

Experimental Design: Carnivore scat surveys were carried out along roads located in grassland and shrubland habitats throughout the Sevilleta NWR. Surveys were done along 20 road based transects in 2008 and 22 transects in 2009. 10 transects were located in grassland areas and 10 in shrubland areas in 2008; there were 12 transects in grassland areas and 10 in shrubland areas in 2009.

Instrumentation: 

Sampling Design: Each scat transect was 1 mile long and was separated from all other transects by at least 1 mile to ensure independence of scat samples collected on different transects. Each transect surveyed in 2008 (n=20) was surveyed a total of three times between June 24th and July 24th, 2008. Each transect surveyed in 2009 (n=22) was surveyed a total of six times between April 13th and November 6th, 2009. For 2009, two surveys were carried out in each of three seasons: spring (April-May 2009); summer (July-August 2009); and fall (October-November 2009).

Field methods: The beginning and end points of each scat transect were marked at the beginning of the summer field season in 2008, and then re-marked as necessary at the beginning of the spring field season 2009, with a wooden stake and a pin flag so that each of the three surveys in 2008 and six surveys in 2009 were carried out along the same road segments. The end points of three transects (D,E, and R) were moved slightly from their original locations in summer, 2008 and two transects were added (U and V) in 2009. The coordinates of all of these new locations were determined via GPS and recorded. Before the first scat survey in 2008, and before the first scat survey in each season in 2009, all transects were cleared of all visible carnivore scat. During each of the three subsequent surveys in 2008, and during the two subsequent surveys in each season in 2009, each complete carnivore scat sample encountered was measured and collected. A sample was considered to be incomplete if it were clearly torn or very small and likely missing part of the sample. When clearing transects and conducting surveys, the transects were driven in a field vehicle (truck) at 5-10mph and the driver looked through both the windshield and front windows for scat samples. In 2008, there was a second observer who would sit in the passenger seat and look through the windshield and front windows. When a particular item could not be identified from within the truck, the observer would get out of the vehicle and investigate the item further. When a carnivore scat sample was encountered, a photograph was taken and the GPS coordinates for the location of the scat were recorded. If the scat was composed of multiple pieces that were spread out along the road, then an attempt was made to record the GPS coordinates of a point midway between the two pieces that were furthest apart. If the scat was not flattened or otherwise degraded, two measurements of maximum diameter and one measurement of length were recorded. When a scat contained multiple pieces, these measurements were generally taken on the longest piece. If part of the scat was flattened, then measurements were taken on the longest, unflattened piece. Maximum diameter was measured using calipers and length was measured using a clear, plastic ruler. Once the measurements were taken, small pieces of the scat were removed using flame sterilized tweezers and placed in a 2mL plastic tube containing DET buffer. The buffer preserved the samples for future genetic analysis. The remainder of the sample was then collected in a ziplock bag for future drying and carbon isotope analysis.

Laboratory Procedures: 

All scat samples were dried for 24 hours at 70 degrees Celsius and, in future, will be prepared and run through a stable carbon isotope analysis in a coupled element analyzer and mass spectrometer. Small subsamples of each scat will be run through a mitochondrial DNA species test. All samples identified as coyotes in this test will then be run through a microsatellite analysis, with 8 loci, to identify individuals.

Quality Assurance: 

Data were recorded in the field and entered into a spreadsheet in Excel. Field recorded comments were removed since they did not add significantly to the value of the data and, in some cases, their importance or meaning would have been difficult to explain. No automated or quantitative data quality checks were performed.

Additional information: 

Additional Information on the personnel associated with the Data Collection / Data Processing Other field crew members:Jon Erz and Teresa Seamster

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