# Presentation: 085796

## EASTERN RED CEDAR EFFECTS ON SILPHIDAE INCLUDING AMERICAN BURYING BEETLES (NICROPHORUS AMERICANUS)

- Thomas L. Walker, Jr. (T. J.) and W. Wyatt Hoback
- University of Nebraska at Kearney

## Outline

**Chapter 2.  **Effects of Eastern Red Cedar on Capture Rates of *Nicrophorus americanus* and Other Silphidae
**Chapter 3. **Effects of eastern red cedar on reproduction of *Nicrophorus* species
**Chapter 4.**  Mark-and-recapture population estimates and short-term movement patterns of *Nicrophorus americanus*

## Chapter 1.  Introduction and Literature Review

- Biological Overview of *N. americanus*
- Distribution and Historical Accounts
- Known occupied habitats
- Potential Causes of Declines
- Concerns with local population/cedars/study areas

## Life History of Nicrophorus americanus

- Taxomomy - Coleoptera: Silphidae: Nicrophorinae
- “Carrion Beetle”
- “Burying Beetle”
- parental care
- Univoltine species
- Nocturnal - temperature dependent activity

## Nebraska Distribution

- Historical Records
- Pre-1992
- Valentine NWR - 1992
- Peyton’s Shrew Traps - 1994
- Loess Canyons - 1994
- State Fair Specimen - 1994 or 1995

- http://ww2.unk.edu/acad/biology/hoback/carrion_beetles

-   Recent Records
- recent trapping efforts

## Habitats

- Formerly thought to be species of eastern deciduous forest
- Current populations are found in:
**Rhode Island** - grassland, pastures, thickets
**Oklahoma/Arkansas** - deciduous forest (primarily oak) and grassland mix
**Kansas** - grassland with scattered woodland
**South Dakota/NC Nebraska** - open grassland with scattered trees, some riparian forest
**SC Nebraska** - prairie/juniper woodland

## Concerns with Loess Canyons

- Cedar encroachment
- 30% of rangeland or more
- Increasing about 2%/year
- Grazing Management
- Stocking rates
- Timing, duration, intensity
- Poor water distribution
- Lack of Diversity
- CS grasses
- forbs, native shrubs

-   Some landowners are doing nothing
-   Some are trying to eradicate their cedars

## Study Area - Gosnell Site

- Privately owned
- 97 hectares
- Removed cedars from about 33 hectares
- Altered grazing management to reduce CS grasses & increase diversity

## Study Area - Wapiti WMA

- State owned Wildlife Management Area
- Purchased in 2004/05
- 777 hectares
- Previously abused
- Rested in 2005
- Will be managed for elk, mule deer, turkey, mixed grass prairie and *N. americanus*

## Climate of SE Lincoln County

- Large temperature variations
- Fairly arid, with most precipitation in spring and summer
- Prevailing wind from SE in summer

## Effects of Eastern Red Cedar on Capture Rates of Nicrophorus americanus and Other Silphidae

- GOALS:
- To evaluate impact of cedar encroachment on foraging of *N. americanus* and other silphids
- To compare capture rates of *N. americanus* and other silphids to determine potential for interspecific competition
- To measure microhabitat conditions in cedar-dominated and grassland trapping sites for comparison with trapping results

## Materials and Methods - Trapping

- Modified USFWS Protocol
- Paired traps, cedar & open
- Laboratory rats for bait
- Identified and counted all carrion beetles captured
- Sexed and marked ABB

## Materials and Methods - Microhabitat Variables

- HOBO data loggers
- Temperature
- Relative Humidity
- Dew Point
- Light Intensity
- Soil Temperature
- Hourly Readings through trapping periods
- Compared to capture rates
- Of *N. americanus*
- Of *N. marginatus *and *N. orbicollis*

## Results

**Results**

## Results - Capture Statistics (all)

- _Species             #        #/TN       Species               #      #/TN_
*N. americanus*     265        0.51         *Ne. surinamensis *1,486      2.90
*N. carolinus*           62        0.12         *Ne. americana            *2     0.004
*N. guttula* *            13        0.03         *O. inaequale*             32      0.06
*N. marginatus* 14,803      28.91         *O. novaboracense    *16      0.03
*N. obscurus            *22        0.04         *T. lapponicus*         794      1.55
*N. orbicollis*      5,906      11.54         *T. truncatus*           806       1.57
*N. pustulatus*          16        0.03          **Silphinae           3,136      6.13**
*N. tomentosus*   6,960      13.59
**Nicrophorus  28,047      54.78**
*** ****denotes new county record                             ****All Silphidae    31,183    60.90**

## Results - Capture Statistics (by habitat)

- _Species          Open   Cedar       Species           Open   Cedar_
*N. americanus*     152A      113          *Ne. surinamensis   *876A           610
*N. carolinus*           36          26         *Ne. americana            *0            2
*N. guttula   *            10            3         *O. inaequale*             17         15
*N. marginatus* 10,489A    4,314         *O. novaboracense    *  7           9
*N. obscurus            *18            4         *T. lapponicus*         602A           192
*N. orbicollis*      1,632A    4,274         *T. truncatus*           580A           226
*N. pustulatus*            4           12          **Silphinae          2,082     1,054**
*N. tomentosus*   2,715      4,245
**Nicrophorus  15,056    12,991**
- A** significant difference P < 0.05  ****                 ****All Silphidae    17,138**A ** 14,045**

## Relative Abundance of Nicrophorinae

***N******. marginatus*****  56 X**
***N. tomentosus  *****26 X**
***N. orbicollis*****     22 X**
*N. carolinus*     0.2 X
*N. obscurus    *0.08 X
*N. pustulatus*  0.06 X*
*N. guttula*       0.05 X
- Potential competition for carrion during reproduction
- * - *N. pustulatus *is a brood parasite
- Potential competition for food with all listed

## Other Competitors?

- Silphinae - good #’s
- different life cycle
- feed on fly larvae and carrion
- Dung Beetles?
- Obviously feed on carrion
- large #’s in some traps
- at least 5 species

## Microhabitat Variables and Capture Rates

- Air Temperature - no relationships with captures
- daily high, nightly low, at sunset or sunset + 2 hours
- Relative Humidity - no relationships with captures
- daily low, nightly high, at sunset or sunset + 2 hours
- Dew Points - no relationships with captures
- combination of temperature and relative humidity
- Light Intensity - no relationships with captures
- nightly readings essentially zeroed out every night at all HOBO data logger locations

## Microhabitat Variables and Capture Rates (continued)

- Positive but weak relationships between temperature and capture rates.

## Microhabitat Variables and Capture Rates (continued)

- Humidity had little impact upon capture rates.

## Microhabitat Variables vs. Habitat Type (Temperature)

## Microhabitat Variables vs. Habitat Type (Relative Humidity)

## Microhabitat Variables vs. Habitat Type (Light Intensity)

## Conclusions - Capture Rates

- Cedars limit or reduce ABB captures
- suggests that detection of prey may be reduced or that *N. americanus* does not like cedars
- relationship not significant with recaptures included
- possible artifact of bait conditions
- Open grassland preferred by *N. marginatus*, *T. lapponicus*, *T. truncatus*, & *Ne. surinamensis*
- Cedar habitats preferred by *N. orbicollis*
- encroachment may be increasing competition

## Conclusions - Interspecific Competition

*N. marginatus*, *N. tomentosus* and *N. orbicollis *all greatly outnumber *N. americanus*
- First two species diurnal, *N. tomentosus* breeds late
*N. orbicollis* nocturnal - could be threat as competitor
*N. carolinus, N. obscurus, N. pustulatus* and *N. guttula* low numbers - not much competition
- Silphinae - Fair numbers, may compete some
- different life cycles and feeding strategies
- Dung Beetles - large numbers feeding on carrion bait

## Conclusions - Microhabitat Variables

- No relationships between temperature, relative humidity, dew points or light intensity and capture rates of *N. americanus, N. marginatus *or *N. orbicollis.*
- Somewhat surprising as Bedick (1997) found high temperatures and low humidity lethal for *N. marginatus*
- Temperature and relative humidity conditions should be better for burying beetles in cedar-dominated habitats.
- Light intensity lower in cedars during day, no difference at night - Light pollution should not be a problem.

## Effects of eastern red cedar on reproduction of Nicrophorus species

- GOALS:
- To determine effects of cedar trees on reproduction of *N. marginatus*
- To determine effects of cedar trees on microhabitat variables that can influence breeding success of *Nicrophorus* species

## Materials and Methods - “Brood Ball” Sets

- Captured *N. marginatus* in baited pitfall traps, separated them by sex (by counting abdominal segments)
- Placed pairs with suitable carrion in cedar-dominated and grassland habitats - 56 in each habitat over 2 years
- placed beneath inverted flower pots within emergence cages
- Checked carcass condition (buried, not buried, or missing) after 1 day, then weekly for 6-7 weeks
- Extracted 1 brood ball per study area and habitat type at 1 week, waited for remainder to progress to emergence or fail
- Recorded known and probable successes, losses and causes of losses

## Materials and Methods - Microhabitat Variables

- Recorded the following microhabitat variables and compared them by habitat type:
- Soil temperature
- Soil moisture
- Soil compaction
- Soil pH
- Litter type and depth

## When all went well.....

*N. marginatus *brood ball

- Freshly emerged, teneral *N. marginatus*

## Results - Brood Balls

-              Known        Suspected            Total
-               _Success          Success            Success_
**Habitat**
- Cedar          5                   21                26 (46%)A
- Open           5                    5                 10 (18%)
**Year**
- 2004            5                  20                 25 (45%)
- 2005            5                    6                 11 (20%)
**Totals        10                 26                 36 (32%)**
**A**** Chi-square test, P < 0.01**

## Results - Brood Balls (Causes of Losses)

-             _Insects   Congeners  Mammals  Heat  Unknown_
**Habitat**
- Cedar        11             12                5            0           2
- Open         15             13                3           13          2
**Year**
- 2004            7               0                8           13          3
- 2005          19             25                0             0          1
**Totals       26             25                8           13          4**

## Results - Microhabitat Variables

-            Carcass                   _Soil Properties_
-          Burial Depth   Comp.        Temp.          Moist.
-                (cm)           (PSI)           (°C)              (%)A
**Habitat**
- Cedar       8.7             402B           21.4B                 65%B
- Open      10.3             549             25.3             59%
- A Soil moisture measured as percent relative saturation.
- B Mann-Whitney Rank Sum Test (P < 0.05)

## Conclusions - Brood Ball Success

- Greater success of brood balls in cedar habitats likely due to a variety of factors:
- Natural Factors
- Soil compaction (easier burial)
- Soil/air temperature (decay of carcass)
- Losses to competitors (insects, congeners, mammals) were very similar between habitats
- Unnatural Factor
- Clay Flowerpots

## Conclusions - Brood Ball Success

- Cedar trees provide conditions advantageous to breeding of *Nicrophorus* species
- soil temp, moisture, compaction
- but too many cedars would likely result in negative impacts due to a loss of diversity and abundance of potential prey items
- Soil Compaction - Livestock activity limited to open areas, has compacted soils there
- reduced stocking rates, or resting pastures might reduce these differences somewhat
- native shrub thickets could also provide similar benefits

## Mark-and-recapture population estimates and short-term movement patterns of Nicrophorus americanus

- GOALS
- To utilize mark and recapture to document short-term movements during trapping periods
- To utilize mark and recapture to estimate population sizes for the study area and Loess Canyons area of SE Lincoln County, Nebraska
- To evaluate current radio telemetry technology for *N. americanus* research and document movements and daytime habitat use

## Materials and Methods - Mark and Recapture

- Beetles were captured as described previously
- Each *N. americanus* was marked with different combination of paint dots
- Testors Model Car Paint
- Released 200-800m away
- Recaptures were recorded and distances determined from GPS locations of traps

## Materials and Methods - Population Estimates

- Utilized the program “Ecostat” (Young and Young 1998) to do population estimates
- Mt Model - Closed population mark-recapture data
- Assumes variation through time in capture probabilities
- Sensitive to changes in #’s, weather and other variables
- Did one population estimate per trapping period
- Used 1 km attraction radius to estimate area surveyed and to extrapolate population #’s for Loess Canyons
- 1,943 km2 of potentially suitable habitat (Bedick et al. 1999)

## Trapping Area (1 km radius around traps)

## Materials and Methods - Telemetry Study

- Transmitters - Micro-Pips (Biotrack, Ltd.)
- Approximately 0.5 grams
- Smaller than the pronotum of *N. americanus*
- Approximately 8 X 10 X 3 mm, with 7 cm antenna
- Last 7-10 days, detection distance up to 3,200 meters
- Attachment
- various glues, epoxies, paints and resins in 2004
- Poncho and vest attempts in 2005
- Receivers/Antennas
- Receiver
- 3-element hand held Yagi

## Results - Mark and Recapture Data

- Trapping         #        Recaptures     Mean     Initial  Same
- _  __Period      Marked  Ind’s (total)  Distance   TOC  Habitat_
- June 04          35           9    (9)     1.185 km       2         5
- Aug 04          32          12  (14)    0.328 km       6         8
- June 05          68          22  (35)    0.493 km     17       23
- Aug 05          65          13  (14)    0.444 km       3         6
- Totals          200          56  (72)    0.538 km     28       42

## Mark and Recapture - Movements

- 3 movements between study areas
- 6.2 km movement in 4 days
- 5.5 km movement overnight
- 4.8 km movement in 5 days
- 8 movements 1.2 to 1.5 km within study areas
- 14 movements 0.5 to 0.8 km
- 19 movements of 33 to 154 m
- 28 “zero” movements

## Mark and Recapture - Other Statistics

- Times recaptured
- 45 once, 7 twice, 3 three times, 1 four times
- 7 marked *N. americanus* in one trap on same day
- Days between captures
- average of 1.76 days between captures
- 48 one day, 14 two days, 2 three days, 3 four days, 2 five days, 1 six days, 2 seven days
- One *N. americanus* captured 5 times in 5 days (3 traps)
- One 3 times in 8 days (same trap)

## Results - Population Estimates

- Trapping   Study Area Pop.  95% Confidence   Regional
-   _Period     Est. + 1 St. Dev           Interval          Pop. Est_.
- June 04         75 _+_ 19.0                 52 - 133           11,184
- Aug 04        120 _+_ 25.1                86 - 190           17,894
- June 05       118 _+_ 13.2                99 - 152           17,546
- Aug 05       322 _+_ 75.5              215 - 522           48,016

## Results - Telemetry Study

- 3 senescent males in 2004
- one would not fly - struggled in grass - released
- one flew 75 m, transmitter was found <10 m from landing point (where beetle burrowed into ground)
- final one flew 150 m, was found less than 30 m from TOC next morning after having been captured and consumed by a bat
- 3 teneral beetles in 2005
- no flight over 10 m
- one moved < 5 m from release point in 2 nights
- one moved about 50 (on ground) in 2 nights
- one transmitter failed

## Problems - Transmitter Attachment

## Slide 48

## Problems - Transmitter Attachment

- Waxy substance exuded by beetles
- released to keep beetles clean
- makes glues useless
- reason for “poncho” and “vest” attachment attempts
- Raised profile with transmitter
- burying beetles frequently burrow or crawl through and under vegetation, sticks, etc.
- raised profile prevents these activities

## Conclusions - Mark and Recapture

*N. americanus *are capable of long-distance movements
- Majority of movements (85%) less than 1.0 km, just 3 movements over 1.5 km
- Number of multiple recaptures, and recaptures up to 8 days after initial capture, suggest that trapping and marking methods are not harming beetles

## Conclusions - Mark and Recapture

- Study Area Population Estimates:
- Suggest large increase in population from 2004-2005
- Could be due to better conditions during trapping
- Could be due to change in management on study areas
- Regional Population Estimates
- 11,000 to 48,000 *N. americanus* in Loess Canyons?

## Conclusions - Radio Telemetry Study

- Close, but not there yet...
- Transmitters have decreased from 15-20 grams to 0.5 grams in last 10 years....
- Need to find ways to get the information on the daytime habitat usage, survival, movements, etc.

## Overall Conclusions

- Cedars may limit carrion detection or use by *N. americanus* and may have increased population of potential competitor, *N. orbicollis*.
- Cedars are providing microhabitat conditions that are favorable for *Nicrophorus* reproduction.
- Mark and recapture data continues to show that Loess Canyons’ population of *N. americanus* is among the largest remaining in the nation.

## Future Conservation Efforts?

- Results somewhat inconclusive - keep open areas open, at most, thin cedars in other areas
- Continued addition of State and/or Federally-owned land in the Loess Canyons region
- Continue to work with private landowners to improve conditions for *N. americanus*.
- Long Term Ecological Research (LTER) unit site in the Loess Canyons??

## Acknowledgements

- U. S. Fish and Wildlife Service - Section 6 Grant Funding
- Nebraska Game and Parks Commission - use of vehicle and equipment
- Gordon Gosnell and NGPC for access to research sites

## Acknowledgements

- My wife, Michelle, and children (Mikaela, Matthew and Marissa) for sticking with me through the last two years
- Trapping assistants - Jeffrey Hamik, Brian Sass, Betty Wieck, John Kilpatrick, Mark Staab, Lance Hastings, Mike Fritz, Joseph Harrin and Nathan Svitak
- Dr. Skinner, Dr. Albrecht and Gerry Steinauer - (Committee) - and Dr. Wyatt Hoback for continuous support and guidance
- Dan Rochford, my boss, for encouraging me to finish something I started too many years ago

## Questions??