The Impact of Management on the Movement and Home Range Size of Indiana’s Eastern Hellbender Salamanders
Emily B. McCallen, Bart T. Kraus, Nicholas G. Burgmeier, and Rod N. Williams
Department of Forestry and Natural Resources
GIS Processing
Hellbenders in Indiana
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Large, fully aquatic salamanders requiring cool, fastflowing lotic systems (Fig. 1)
• All points recorded on Garmin Rino 86 and imported into ESRI ArcGIS
10.2 (Fig. 3)
Once found in tributaries throughout the Ohio and
Wabash River watersheds
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Now restricted to a single river in southern Indiana
(Fig. 2)
Linear Home Range (LHR) Calculation
20 years of monitoring has revealed significant,
ongoing declines in the abundance of hellbenders in
the Blue River
No evidence of successful recruitment during this time
leading to an increasingly geriatric population
Movement and Management
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Results
Movement Probability
Distance between points calculated with R package “geosphere”
Variable
Intercept
Time Since Last Observation
Time Since Release
Site Density
Fall
Predicted movement
probability over time
• Points snapped to line representing river midpoint
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21 resident adult hellbenders tracked at 8 sites
P-value
<2e-16
0.0001
<2e-16
0.0119
0.0148
Estimate
2.94
0.115
-0.154
0.688
0.698
SE
0.106
0.038
0.070
0.083
0.187
P-value
<2e-16
0.0027
0.0286
<2e-16
0.0002
Variable
Estimate
SE
P-value
Intercept
Number of Observations
Status
5.1927
0.2055
0.599
0.1359
0.1137
0.2412
<2e-16
0.0707
0.0129
Estimate
9.562
-1.0266
SE
0.3901
0.4260
P-value
<2e-16
0.016
Variable
Intercept
Time Since Last Observation
Site Density
Fall
Status
• Points connected and distance (m) of line measured (Fig. 3)
Mean Convex Polygon (MCP) Home Range Calculation
Predicted movement
probability as a function of
site density
• Minimum bounding geometry tool with convex hull geometry type
Home Range-LHR
• Polygon area (m2) measured (Fig. 3)
Predicted movement
distance for resident and
translocated hellbenders
Pre-management
2008-2009
SE
0.197
0.048
0.034
0.082
0.090
Distance Moved
Movement tracked 3x weekly during field season
(May – November) via radio telemetry
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Estimate
-1.840
-0.184
0.338
-0.207
0.218
Home Range-MCP
Variable
Intercept
Age
Post-management
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2011-2012
42 individuals tracked at 2 sites where translocations
were undertaken to increase local densities
Site 1 contained resident adult hellbenders (11) and
translocated adult hellbenders (11) from isolated sites
across the river
Site 2 contained resident adult hellbenders (10) and
translocated captive-reared juvenile hellbenders (10)
Research Question
Figure 1. An eastern
hellbender on the banks of
the Blue River
Model Type
Random Effects
Error Distribution
Management
Financial support was provided by the Indiana Department of Natural
Resources, Division of Fish and Wildlife, Wildlife Diversity Section, State
Wildlife Improvement Grant T07R11 and the Department of Forestry and
Natural Resources at Purdue University. Eastern Hellbenders were collected,
handled, and processed following standard procedures approved by the
Purdue Animal Care and Use Committee (PACUC; 08-025-11) and in
accordance with Indiana Scientific Permit # 13-0087.
Figure 3. Location points,
LHR and MCP for an
individual hellbender in the
study
Predicted movement
distance as a function of site
density
Statistical Models
Are hellbender movement patterns or home range sizes in Response
the Blue River impacted by management actions,
temporal patterns, or individual hellbender
Covariates:
characteristics?
Acknowledgements
Figure 2. The location of the
Blue River in southern
Indiana
Predicted
LHR and MCP
home range sizes
for statistically
independent
groups
Covariates:
Temporal
Generalized Linear Mixed Model
Generalized Linear Model
Discussion
Management
Animal ID
Site ID
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Negative Binomial
Binomial
Movement Probability
Less movement (probability and distance) at higher site densities
Temporal
Movement Distance
Site Density (hellbenders/kilometer)
LHR Size
MCP Size
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Initial period of higher movement probability decreases over time
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More movement (probability and distance) in the fall which is when breeding
occurs
Management (pre or post)
Individual
Time Since Release
Season (summer or fall)
Covariates: Age (juvenile or adult)
Status
Sex (female or male)
Individual
(translocated or resident)
Covariates:
Number of Observations
Time Since Last Observation
Control
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Translocated hellbenders move more resulting in larger home ranges
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Effect more pronounced in juvenile age classes