Elsevier

Forest Ecology and Management

Volume 432, 15 January 2019, Pages 225-230
Forest Ecology and Management

A regional scale assessment of habitat selection and home range of the eastern rat snake in pine-dominated forests

https://doi.org/10.1016/j.foreco.2018.09.018Get rights and content

Highlights

  • Ichauway snakes’ home ranges were at least 2.6 times larger than other sites.

  • Snakes at all sites selected open edge and pine habitat at the landscape scale.

  • Snakes at all sites were most likely found in large, mature oak trees.

  • Hardwood removal activities may have limited suitable trees that rat snakes use.

Abstract

An animal’s spatial ecology may provide insight into how resources are distributed or potentially limiting across its home range. Some species with broad geographic distributions may exhibit intraspecific variation in space use among populations given the spectrum of available habitat across their range. Animals may need to move further in habitats with limited resources thereby lowering survival. Species, like the eastern rat snake (Pantherophis alleghaniensis), occur throughout the eastern USA and are thought to be strongly tied to hardwood forests. However, their occurrence in pine-dominated forests in the southeastern USA suggests they have broader habitat requirements than previously noted. Our objective was to investigate patterns of habitat use and spatial ecology for eastern rat snakes across multiple pine-dominated forests in Southern Georgia and Northern Florida to capture regional differences in eastern rat snake resource use. We examined home range and habitat use at multiple spatial scales for 30 radio-telemetered snakes from three sites; one in Georgia (Pebble Hill) and Florida (Tall Timbers) during 2004–2005 and one more northern site in Georgia (Ichauway) during 2010–2012. Snakes tracked on Ichauway had a mean home range size that was 3.9 times larger (95% Mean Convex Polygon [MCP], 13.6 ± 8.2 ha) than the estimate for Tall Timbers (3.5 ± 3.2 ha) and 2.6 times larger than the estimate for Pebble Hill (5.3 ± 3.2 ha). Snakes at all three sites selected primarily open edge and pine habitat at the landscape scale and were most likely to be found in large, mature oak trees (Quercus spp.). At Ichauway, hardwood removal activities associated with longleaf pine (Pinus palustris) restoration reduced the number of hardwood trees per hectare by 33% in hardwood removal areas from 1998 to 2014. This management approach included limiting suitable large oak trees that rat snakes use and may help explain the variation in home range size and the number of snakes captured at Ichauway (n = 14) compared to the other two sites (Tall Timbers, n = 154, Pebble Hill, n = 127).

Introduction

The breadth of an animal’s movements and spatial ecology can be influenced by many factors, including reproduction (Bertrand et al., 1996, Gibbons and Semlitsch, 2001), food availability (King and Duvall, 1990, Mares et al., 1982, Shine et al., 2003), environmental conditions (Blouin-Demers and Weatherhead, 2001a, Blouin-Demers and Weatherhead, 2001b, Lillywhite, 2001, Webb and Shine, 1998), and habitat structure/resource availability (Gregory et al., 2001, Kie et al., 2002, Pasinelli, 2000). Given similar diet preferences and reproductive ecology within a species, habitat type and availability may have the largest influence on plasticity of space use across a species’ geographic distribution. Animals may need to travel longer distances if particular resources are limiting, possibly impacting survival, due to increased energy expense and predation risk (Gregory et al., 2001).

The biologically diverse longleaf pine (Pinus palustris) ecosystem was once the dominant habitat type across the Coastal Plain of southeastern USA. Currently, it is one of the most globally endangered ecosystems in North America (<5% remains), mainly due to conversion to agriculture and industrial pine plantations, urban development, and fire suppression (Noss et al., 1985, U.S. Department of Agriculture [USDA], Forest Service., 2016, Ware et al., 1993). In the absence of frequent fire, longleaf pine forests become hardwood dominated systems (Gilliam and Platt, 1999, Heyward, 1939). Species that require open canopy pine forests and abundant herbaceous ground cover, including the red-cockaded woodpecker (Picoides borealis, Rudolph et al., 2002), gopher tortoise (Gopherus polyphemus, Yager et al., 2007), and snakes, like the eastern diamondback rattlesnake (Crotalus adamanteus), and the eastern indigo snake (Drymarchon couperi) (Hoss et al., 2010, Hyslop et al., 2014) are thought to have declined in fire-suppressed forests. But other species, within the former range of the longleaf pine ecosystem associated with hardwoods, e.g., certain songbirds (Conner et al., 2002), raccoon (Procyon lotor, Kirby et al., 2017) and rat snakes (Pantherophis spp., Blouin-Demers and Weatherhead, 2001a, Blouin-Demers and Weatherhead, 2002, Fitch, 1963, Reinert, 1993, Stickel et al., 1980), may have benefitted from increases in hardwoods in pine forests. Eastern rat snakes (P. alleghaniensis) are predators of eggs and chicks of the northern bobwhite (Colinus virginianus), a popular gamebird species in the southeastern U.S. (Staller et al., 2005) and the federally protected red-cockaded woodpecker (Jackson, 1978, Neal et al., 1993). Hence, there is considerable interest in whether fire suppression may, indirectly, have resulted in increased populations of eastern rat snakes, as well as in identifying habitat restoration methods to minimize impacts of this native predator (Sash, 2007, Stapleton, 2005). Although historic data on eastern rat snake abundance are lacking, we suspected that snakes may use habitat resources differently across their range, especially in areas where management and restoration practices select against preferred habitats. Therefore, our objective was to investigate patterns in habitat use for eastern rat snakes across multiple pine-dominated forests. We focused on three managed pine forests in South Georgia and North Florida to capture regional and management-specific differences in eastern rat snake resource use.

Section snippets

Study area

We collected data on three privately-owned pine-dominated properties in southwest Georgia and northern Florida that were managed for restoration and conservation of southeastern pine forest endemic species (e.g. red-cockaded woodpecker, gopher tortoise) and northern bobwhite quail hunting. All three sites were managed with prescribed fire (1–3 year rotation) and hardwood removal to restore fire corridors and promote an open canopy pine forest with species-rich ground cover (Edwards et al., 2013

Home range, macrohabitat, and refugia selection (all sites)

Our analyses included data from 30 adult eastern rat snakes (9 from Ichauway, 10 from Tall Timbers, and 11 from Pebble Hill) radio-tracked from 37 to 495 days (Table 3). We excluded 4 snakes from analyses that had <12 locations due to loss of transmitter signal or a mortality event. We observed an average of 52.6 ± 14.9 locations on Ichauway, 23.8 ± 11.2 mean locations on Tall Timbers and 28.9 ± 12.9 mean locations on Pebble Hill (Table 3). Snakes at all sites exhibited some degree of site

Discussion

Ichauway home range estimates (13.6 ha) were not only 3.9 times larger than Tall Timbers (3.5 ha) and 2.6 times larger than Pebble Hill (5.3 ha) but were also much larger than estimates reported for sites outside of Georgia and Florida: [5.6 ha, Arkansas (Mullin et al., 2000), 9.5 ha, Maryland (Durner and Gates, 1993), 7.6 ha, Ontario (Weatherhead and Hoysak, 1998), 9.7 ha, Illinois (Foster et al., 2006), 5.6 ha, Illinois (Carfagno and Weatherhead, 2008)], with one exception [35.1 ha, 95%

Management implications

Our findings suggest that hardwood removal as a land management activity in longleaf pine dominated systems may affect eastern rat snake populations. Snakes on Ichauway re-used individual oak trees more often than at the other two sites and moved further between individual trees. We also noted large differences in captures of eastern rat snakes at traps among the three sites over the study period [e.g., 14 snakes at Ichauway (n = 16 traps), 154 at Tall Timbers (n = 15 traps) and 127 at Pebble

Declaration of interest

None.

Acknowledgements

We thank B. Schlimm, M. Dziadzio, B. O’Hanlon, T. Baldvins, A. Vicente, C. Oliver, C. Faidley, S. Lillie, R. King, A. Ballou, N. Smith, J. Murdock, S. Ruane, J. Danielson, and P. Hill for field assistance. We thank B. Rutledge and S. Jack for providing hardwood removal data. We thank L. M. Conner for statistical support, J. Brock for GIS assistance, and B. Howze, B. Rutledge, and J. Jensen for reviewing an earlier draft of this manuscript. Funding provided by the J.W. Jones Ecological Research

References (56)

  • G.L.F. Carfagno et al.

    Does mammalian prey abundance explain forest-edge use by snakes?

    Ecoscience

    (2006)
  • G.L.F. Carfagno et al.

    Energetics and space use: intraspecific and interspecific comparisons of movements and home ranges of two colubrid snakes

    J. Anim. Ecol.

    (2008)
  • R.N. Conner et al.

    Avian community response to southern pine ecosystem restoration for red-cockaded woodpeckers

    Wilson Bull.

    (2002)
  • G.M. Durner et al.

    Spatial ecology of the black rat snakes on remington farms, maryland

    J. Wildl. Manag.

    (1993)
  • L. Edwards et al.

    The natural communities of Georgia

    (2013)
  • S.N. Ellis-Felege et al.

    Predator reduction results in compensatory shifts in losses of avian ground nests

    J. Appl. Ecol.

    (2012)
  • H.S. Fitch

    Natural history of the black rat snake (Elaphe o. obsoleta) in Kansas

    Copeia

    (1963)
  • C.D. Foster et al.

    Elaphe spiloides (central ratsnake) habitat use

    Herpetol. Rev.

    (2006)
  • Franz, R., 1995. Habitat use, movements, and home range in two species of ratsnakes (genus Elaphe) in a North Florida...
  • J.W. Gibbons et al.

    Activity patterns

  • F.S. Gilliam et al.

    Effects of long-term fire exclusion on tree species composition and stand structure in an old-growth Pinus palustris (Longleaf Pine) forest

    Plant Ecol.

    (1999)
  • P.T. Gregory et al.
  • F. Heyward

    The relation of fire to stand composition of longleaf pine forests

    Ecology

    (1939)
  • S.K. Hoss et al.

    Multiscale influences of landscape composition and configuration on the spatial ecology of Eastern diamond-backed rattlesnakes (Crotalus adamanteus)

    J. Herpetol.

    (2010)
  • N.L. Hyslop et al.

    Effects of body size and sex of Drymarchon couperi (Eastern Indigo Snake) on habitat use, movements, and home-range size in Georgia

    J. Wildl. Manage.

    (2014)
  • J.A. Jackson

    Competition for cavities and red-cockaded woodpecker management

  • D.H. Johnson

    The comparison of usage and availability measurements for evaluating resource preference

    Ecology

    (1980)
  • J.G. Kie et al.

    Landscape heterogeneity at differing scales: effects of spatial distribution of mule deer

    Ecology

    (2002)
  • Cited by (7)

    • The influence of prescribed fire on site selection in snakes in the longleaf pine ecosystem

      2021, Forest Ecology and Management
      Citation Excerpt :

      Burrowing species, like the gopher tortoise (Gopherus polyphemus), oldfield mouse (Peromyscus polionotus), and southeastern pocket gopher require open habitats maintained by fire (Davenport, 1964, Landers and Speake, 1980, Auffenberg and Franz, 1982, Diemer, 1986) and their burrows provide shelter for snakes, including eastern diamondbacks, eastern coachwhips, and Florida pine snakes (Means, 2007, Steen et al., 2010, Miller et al., 2012, Smith et al., 2017, Knapp et al., 2018, Murphy, 2019). Frequent fire also facilitates development of subterranean cavities by burning decomposing taproots and lateral roots of pine stumps (Means, 2007) used by eastern diamondbacks, eastern kingsnakes and gray ratsnakes (Means, 2007, Steen et al., 2010, Smith et al., 2017, Howze et al., 2019, Murphy, 2019). This study capitalized on existing upland snake data from previous habitat selection and spatial ecology studies conducted at our site.

    • The moss genus Didymodon as an indicator of climate change on the Tibetan Plateau

      2020, Ecological Indicators
      Citation Excerpt :

      Furthermore, the potential distribution pattern of Didymodon is more sensitive to Bio3 and Bio4, compared to that of Bryoerythrophyllum. Additionally, habitat preferences may have the largest influence on the plasticity of space use across a taxon’s geographical distribution (Howze et al., 2019). Didymodon prefers drought regions in contrast to Bryoerythrophyllum.

    • The longleaf pine forest: Long-term monitoring and restoration of a management dependent ecosystem

      2019, Journal for Nature Conservation
      Citation Excerpt :

      The reduction in hardwoods across the property may affect wildlife species more dependent on these habitat types. For example, eastern rat snakes have larger home ranges on Ichauway in comparison to other areas with more hardwood habitat (Howze, Sash, Carroll, & Smith, 2019). Effects of management, such as appropriate fire regime, will be used to inform an adaptive management program and allow us to be more efficient practitioners of longleaf restoration.

    View all citing articles on Scopus
    View full text