Small Mammal Surveying Protocol

Transcription

1 Small Mammal Surveying Protocol Jug Bay Wetlands Sanctuary May 2016 Authors: Rebecca Natoli Rachel Schadegg Lydia Nichols-Russell Jenifer Mallinoff

2 Table of Contents: I. Introduction II. Small Mammal Surveying Protocol A. Live Trapping B. Track Tubes III. IV. Map of Surveying Area Equipment List for Protocol A. Live Trapping B. Track Tubes V. Track Key for Small Mammals Found in Jug Bay VI. Data Collection A. Sample Data Sheet B. Description of Database VII. Bibliography 1

3 I. Introduction Jug Bay Wetlands Sanctuary contains a rich variety of habitats preferred by small mammals including riparian and upland forests, tidal freshwater marshes, fields, and meadows. Due to this diversity in habitats, it is likely that the sanctuary is home to many small mammal species. A wide variety of mice, shrews, moles, voles, rats, squirrels, and others may be present but have not yet been extensively surveyed for. This surveying protocol is intended to assist sanctuary staff and researchers in building a database of presence data for individual species at Jug Bay. For the purposes of this protocol, small mammals generally refers to smaller members of the taxonomic orders Rodentia and Insectivora. Small mammals generally weigh less than 5 kg and can be herbivorous primary consumers, insectivorous secondary consumers, or both. They establish their ecological importance by participating in cyclic predator-prey relationships within the ecosystems in which they are found. They serve as a main food source for larger carnivorous mammals, snakes, and raptors. They are often most active at night or during dawn or dusk. They must consume significant amounts of food to maintain metabolic homeostasis, so a considerable amount of time is spent foraging to satiate their high energetic needs. The bodies of small mammals have high surface-area-to-volume ratios which leaves them vulnerable to heat loss; behavioral characteristics such as burrowing help to protect them against extreme temperatures in their environments. Small mammals generally have relatively short life spans. Some shrews, for example, may live up to only about a year or two old. However, small mammals often have high reproductive rates. Gestation periods are often only around a month long and litter sizes range from only a few to over ten offspring. Sexual maturity is reached between one month old and around a year old, depending on the species (Merritt 2010). Sherman live trapping and track tubes were chosen as the primary survey method for this project due to their effectiveness and feasibility. In this project, live trapping should be conducted by professional biologists, while track tubes surveys can be conducted by citizen scientist volunteers. These volunteers must complete a training session run by professional biologists on the proper setup and deployment of the test tubes. To estimate presence of small mammals the traps will be placed within the the grid system previously established by the Jug Bay Wetlands Sanctuary. This grid system has been overlaid onto a map of the entire sanctuary and has been used for many other research projects conducted at the sanctuary in the past. Therefore distributing the traps within this grid system will allow for efficiency and consistency. The Sherman live trap is a simple box trap used to capture a variety of small mammals and comes in sizes that accommodate a range of small mammal species. Since the capture rate of small mammals can often depend on the size, type and location of the trap, we are using two sizes (3in x 3.5in x 9in and 4in x 4.5in x 15in) for this project. For small mammal surveys in 2

4 temperate regions, live trapping is normally conducted once a year during the summer breeding season. Whenever live traps are used, it is critical to consider the weather conditions during the event; trapping should be avoided during severe cold, hot or rainy conditions in order to prevent unnecessary mortalities (Manley et al. 2006). Track tubes are often used as a time-efficient and low cost form of passive method commonly used to study the presence and habitat preferences of a variety of small mammal species (Weiwel 2007). Track tube surveys cause low levels of disturbance in small mammal communities; they reduce the risk of humans exposure to diseases carried by small mammals, such as hantavirus, and reduce the risk of significant mortality or injury that may arise during live-trapping. While track tubes are well suited methods for estimating species presence, they are almost always used in conjunction with live capture surveys in order for researchers to determine reliable abundance estimates of small mammal at an ecosystem level. 3

5 II. Small Mammal Surveying Protocol Note: Locations for the trapping grid were assigned by habitat diversity. Areas were chosen that included all habitats found in Jug Bay, including coniferous forest, hardwood forest, grassland, and wetland. A. Live trapping: Performed by biologists over a three-day period once a year in order to establish the presence of exact species. 1. Distribution - Number 100 3in x 3.5in x 9in Sherman traps. 50 traps will be placed in the northern section of Jug Bay, 50 will be placed in the southern section. - Number 20 4in x 4.5in x 15in Sherman traps. 20 traps will be placed in the northern section and 20 in the southern section. - Traps must be placed at least 10m apart and should be placed in one quadrat of the grid to facilitate set-up and checking. The cycle will begin with the northwest quadrat in year 1, followed by northeast in year 2, southeast in year 3, and southwest in year 4. The cycle will restart in year Trap Set-up - Follow package instructions to put together box trap. - Put cotton batting in back of box to act as insulation/bedding. - Bait traps with peanut butter and oat mixture. Mix approximately 2 tbsp. peanut butter with 1 tbsp. oats and place on piece of plain folded paper (to keep the trap clean) in front of cotton batting. - Distribute traps. - Camouflage traps using twigs and leaves so that they are not apparent from any paths and do not stand out in the surroundings. *Do not trap in periods of intense heat, cold, or rain to avoid harming animals.* 3. Trap Checking - Traps should be set just before sundown. - After sunrise, approximately 12 hours after they were set, traps should be checked. - Put on latex gloves (carry leather gloves in case mustelid or larger mammal is trapped). - If an animal has been trapped, cover opening in small cloth sack and empty animal into sack. 4

6 - Grasp animal by nape of neck within sack and pull back opening once animal is secure. - Identify species. - Record data. - Mark animal with permanent marker to prevent duplicate data in the event of recapture over sampling period. - Release. - Re-bait and set trap. 4. Post-sampling period - Wearing rubber gloves and a face mask, disinfect traps. Dispose of bedding in a plastic bag and throw away. For traps, sanitize with a solution of 1:9 household bleach to water (or 1.5 C household bleach, 1 gal. water). - Dispose of gloves and face mask when done. B. Track Tubes: Performed by citizen scientists (volunteers) during 4 events per year at 3 month intervals. Each track tube event will take place over 3 days. The purpose of these surveys is to establish the presence of groups of small mammals or exact species if possible. 1. Track Tube Set-up - Number 100 1ft long, 8cm diameter PVC pipes. - At both ends of each tube, secure an approximately 2in x 2in piece of adhesive felt with thin pieces of duct tape. Place the felt about half an inch from the opening of the tube to avoid the ink getting wet. - Use thin pieces of duct tape to secure cardstock on the bottom of each tube, between the pieces of felt. - Mix 2 parts mineral oil to 1 part black-powdered ink. Sufficiently wet felt squares with ink. - Bait tube with peanut butter and oat mixture. Mix approximately 2 tbsp. peanut butter with 1 tbsp. oats and place in the center of the tube. - Place tube on top of several sticks to elevate it slightly off of the ground. - Secure tube into ground with 2 u-shaped wire hold downs on either side and zip ties connecting the hold downs over the top of the tube. 2. Distribution - 50 track tubes will be placed in the northern grid and 50 in the southern grid. - At each event, tubes will be placed in a different quadrat of the grid. At the first event, tubes will be placed in the northwest quadrat and will then move clockwise. At event 2 (3 months later) tubes will be placed in the 5

7 northeast quadrat. Event 3 in southeast and event 4 in southwest. The cycle will start over at event 5, which will begin year 2 of data collection. - 4 track tubes will be placed at least 10 m apart in each square of quadrat, totaling in 48 tubes for all 12 squares. The extra 2 tubes can be placed in the squares of your own choosing. *Try to avoid setting up track tubes in the rain as the ink will bleed and tracks will be difficult to identify.* 3. Track Tube Checking - Tubes should be set out on the morning of day 1. - Tubes should be checked 24 hours later on day 2. Ink pads, cardstock, and bait should be replaced if tracks are seen. - Record data and take pictures of tracks seen on day 2. - Check tubes 24 hours later on the morning of day 3. - Record data and take pictures of tracks seen on day 3. - Remove track tubes and clean them for next sampling event. 6

8 III. Map of Surveying Area A. Northern Sampling Site. Grids x O-V. B. Southern Sampling Site. Grids x K-R. 7

9 IV. Equipment List for Protocol A. Live trapping: in x 3.5in x 9in Sherman traps, $16.96 per trap in x 4.5in x 15in Sherman traps, $33.71 per trap Gloves, $9 per carton (100 pairs)-- Gloves x 12 cloth sack, $ Permanent marker, $6.34 for 2-- B. Track tubes: 8

10 ft long, 8cm diameter PVC pipe, $ for 20ft Contact paper (White cardstock), $10.88 for 250 sheets (Neenah Exact Index) Adhesive white felt, $7.99 for 6 12 x9 sheets-- search Stick It Felt solid color 4. Black Powdered ink, $6.93 for 0.75 oz Mineral oil, $8.48 for 16 oz.-- 9

11 6. Duct tape, $10.25 for 50 yd.s Peanut butter, $9.99 for 80 oz. (Jif double pack)-- grocery store 8. Oats, $2.81 for 18 oz. (Quaker Oatmeal Oats)-- grocery store U-shaped wire hold downs, $400 for 200 (Orbit DripMaster /2-Inch to 5/8- Inch Loop Stake, Pack of 200)-- 10

12 10. Zip ties-- hardware store 11

13 V. Track Key for Small Mammals Potentially at Jug Bay 1. Northern Short-Tailed Shrew (Blarina brevicauda) 2. Masked Shrew (Sorex cinereus) 3. Least Shrew (Cryptotis parva) 12

14 4. Eastern Mole (Scalopus aquaticus) 5. Star-nosed Mole (Condylura cristata) 6. Eastern Chipmunk (Tamias striatus) 7. Eastern Gray Squirrel (Sciurus carolinensis) 13

15 8. White-footed Mouse (Peromyscus leucopus) 9. Meadow Vole (Microtus pennsylvanicus) 10. House Mouse (Mus musculus) 14

16 11. Marsh Rice Rat (Oryzomys palustris) 12. Eastern Harvest Mouse (Reithrodontomys humulis) 13. Meadow Jumping Mouse (Zapus hudsonius) 15

17 14. Woodland Vole (Microtus pinetorum) 15. Southern Bog Lemming (Synaptomys cooperi) VI. Data Collection A. Sample Data Sheet 16

18 i. A sample data sheet for live trapping. ii. A sample data sheet for track tubes. B. Description of Database Data will be compiled on site using printed data sheets. The information will be logged into a larger spreadsheet following the same labelling system using Google sheets. Volunteers are encouraged to take photos of tracks and these should be ed to an address created for this purpose using the same labelling system as that of the data sheet (Grid square-yyyymmdd-trap Number). The photos will then be archived and can be located by title should they become relevant. 17

19 VII. Bibliography Jug Bay Wetlands Sanctuary Checklist of mammals of the Jug Bay Wetlands Sanctuary. < Accessed 5 May Manley, P.N., B. Van Horne, J.K. Roth, W.J. Zielinski, M.M. McKenzie, T.J. Weller, F.W. Weckerly, and C. Vojta Multiple species inventory and monitoring technical guide. U.S. Forest Service, Washington Office, Washington, D.C., USA. Merritt, J.F The biology of small mammals. Johns Hopkins University, Baltimore, Maryland, USA. Nams, V.O., and E.A. Gillis Changes in track tube use by small mammals over time. Journal of Mammalogy 84(4): Pearson D.E., and L.F. Ruggiero Transect versus grid trapping arrangements for sampling small-mammal communities. Wildlife Society Bulletin 31(2): Weiwel, A.S., W.R. Clark, and M.A. Sovada Assessing small mammal abundance with track-tube indices and mark -recapture population estimates. Journal of Mammalogy 88(1):