Response of soricid populations to repeated fire and fuel reduction treatments in the southern Appalachian Mountains
Section snippets
Study objectives
The National Fire and Fire Surrogate Study was initiated in 2000 in 13 different ecosystems across the United States to assess the effects of prescribed fire and fire surrogate treatments on vegetation, wildlife, pathogens, soil, and the forest floor and to evaluate such variables as fire behavior, fuel, smoke, economics, and wood product utilization. Management objectives at our study site were to restore the area to an open woodland structure, reduce potential wildfire severity, and increase
Study area
Our study was conducted on the 5481-ha Green River Game Land (GRGL) in the southern Appalachian Mountains of Polk County, North Carolina. The southern Appalachian Mountains harbor a high diversity of shrews and are an appropriate location to research their response to fuel reduction treatments (Ford et al., 2005). Elevation on the GRGL ranged from 366 to 793 m. Two of our sites (35°17′9″N, 82°19′42″W) were located approximately 2.9 km NW of our third site (35°15′42″N, 82°17′27″W). Forest stands
Methods
Our experimental design followed the National Fire and Fire Surrogate Study guidelines. Three blocks of 4 treatment areas were implemented in a randomized complete block design for a total of 12 treatment areas. The 4 treatments were randomly assigned to areas within each block. Treatments, representing different fuel reduction options, consisted of an untreated control, a twice-burned treatment, a mechanical understory cut, and a combined mechanical understory cut + twice-burned treatment. Each
Treatments
Mechanical understory cut treatments were conducted between December 2001 and February 2002, 1 year before the first prescribed burn. Trees ≥1.8 m tall and <10.2 cm diameter at breast height (dbh) and shrubs regardless of size were cut using chainsaws and left on site. The first burns were conducted in March 2003. Treatment areas within 2 blocks were ignited by helicopter using spot fires and within 1 block by hand using spot fires and strip-headfires (Greenberg et al., 2007a). Maximum
Soricid sampling
The 2 drift fence arrays per treatment area installed in 2001 were reopened from 17 May to 16 August 2006. We installed 1 additional array in each treatment area, ≥100 m from original arrays; these were opened concurrently on 11 July so that 3 arrays per treatment area were operational from 11 July to 16 August 2006. In 2007, all 3 drift fence arrays per treatment area were opened from 15 May to 13 August. The tri-arm (‘Y’ formation) arrays (Kirkland and Sheppard, 1994), constructed of 50-cm
Habitat data
Habitat variables were measured in all treatment areas during the summer of 2006, the first summer after the second burn. Variables recorded were density, volume, and percent cover of coarse woody debris, litter depth, duff depth, basal area of live and dead trees, percent herbaceous cover, and percent shrub cover. Shrubs were recorded in 2 height categories: < or ≥1.4 m.
We established permanent gridpoints spaced at 50-m intervals throughout each treatment area. Leaf litter and duff depth were
Analyses
We defined relative abundance as the number of shrews captured per 100 array nights. Live and dead shrews were combined in analyses. Shrew relative abundance was compared among treatments using a randomized complete block design ANOVA (SAS v.9.1.3, Cary, NC). We also compared relative abundance per 100 array nights for the most common species, the southeastern shrew (Sorex longirostris). Treatment means of relative abundance were compared using Tukey's Honestly Significant Different (HSD) test.
Results
Leaf litter depth was lower in twice-burned and mechanical + twice-burned treatment areas than in mechanical or control treatment areas; duff depth was lower in mechanical + twice-burned treatment areas than in all other treatment areas (Table 1). Live-tree basal area was 43% lower and basal area of snags was 245% greater in mechanical + twice-burned treatment areas than in mechanical treatment areas because of higher tree mortality (Table 1). Percent cover of shrubs ≥1.4 m was 96% lower in mechanical +
Soricids
We captured 5 species of shrews over both years: 13 least shrews (Cryptotis parva), 53 northern short-tailed shrews (Blarina brevicauda), 23 pygmy shrews, 51 smoky shrews (Sorex fumeus), and 130 southeastern shrews. Least shrews were not captured in twice-burned treatment areas in 2006. Pygmy shrews were not captured in mechanical + twice-burned treatment areas in 2006 or in twice-burned treatment areas in 2007. All other species were captured in all treatments both years. We captured 13 live
Discussion
Our results indicate that shrew response to fuel reduction treatments was minimal, even after 2 prescribed burns and 4–5 years after initial treatments. Shrew abundance differed only between mechanical and mechanical + twice-burned treatment areas. These longer-term results indicate that shrew response to these treatments was consistent with the shorter-term response that was documented soon after initial treatments in the previous study (Greenberg et al., 2007a). During the first 2 years after
Conclusion
Shrew abundance is not greatly affected by prescribed burning for fuel reduction in the southern Appalachian Mountains. However, hot fires that open the canopy may have a slight negative effect on some shrew species, at least immediately after disturbance. On the other hand, treatments that add to the leaf litter layer may benefit shrew populations. Longer-term studies of shrew response to different levels, combinations, and frequencies of fuel reduction treatments could improve our
Acknowledgments
This is Contribution Number 193 of the National Fire and Fire Surrogate Project, funded by the US Joint Fire Science Program, the US Forest Service, Southern Research Station (SRS-4156) through the National Fire Plan, and the North Carolina State University, Department of Forestry and Environmental Resources. A US Forest Service team, consisting of R. Phillips, H. Mohr, G. Chapman, C. Flint, and M. Smith assisted in the field and collected all habitat, fuel, and fire data. K. Pollock provided
References (45)
- et al.
Small mammals in young forests: implications for management for sustainability
Forest Ecology and Management
(2001) - et al.
Arthropod response to prescription burning at the soil–litter interface in oak–pine forests
Forest Ecology Management
(2006) - et al.
Effects of a community restoration fire on small mammals and herpetofauna in the southern Appalachians
Forest Ecology and Management
(1999) - et al.
Soricid abundance in partial overstory removal harvests and riparian areas in an industrial forest landscape of the central Appalachians
Forest Ecology and Management
(2001) - et al.
Short-term response of shrews to prescribed fire and mechanical fuel reduction in a Southern Appalachian upland hardwood forest
Forest Ecology and Management
(2007) Fire and the development of oak forests
Bioscience
(1992)- et al.
Litter decomposition, nitrogen dynamics and litter microarthropods in a southern Appalachian hardwood forest 8 years following clearcutting
The Journal of Applied Ecology
(1988) Niche relationships of two syntopic species of shrews, Sorex fumeus and Sorex cinereus, in the southern Appalachian Mountains
Journal of Mammalogy
(2000)- et al.
Bringing fire back: the changing regimes of Appalachian mixed-oak forests
Journal of Forestry
(2001) - Brose, P.H., Tainter, F., Waldrop, T.A., 2002. Regeneration history of three Table Mountain Pine/Pitch Pine stands in...
The role of vertebrate predations in the biological control of forest insects
Annual Review of Entomology
The water exchanges of some small mammals
Ecological Monographs
Pre-Columbian Native American use of fire on southern Appalachian landscapes
Conservation Biology
Body size, prey size, and community structure in insectivorous mammals
Ecology
Shrews in managed northern hardwood stands in the Allegheny Mountains of West Virginia
Influence of elevation and forest type on community assemblage and species distribution of shrews in the central and southern Appalachian Mountains
Contiguous allopatry of the masked shrew and southeastern shrew in the southern Appalachians: segregation along an elevational and habitat gradient
Journal of the Elisha Mitchell Scientific Society
Sorex longirostris
Mammalian Species
Blarina brevicauda
Mammalian Species
Factors influencing the local distribution of shrews
American Midland Naturalist
Seasonal abundance of ground-occurring macroarthropods in forest and canopy gaps in the southern Appalachians
Southeastern Naturalist
Cited by (9)
Shrew response to variable woody debris retention: Implications for sustainable forest bioenergy
2015, Forest Ecology and ManagementCitation Excerpt :Shrews are key components of forest food webs and have been used as indicators of the ecological effects of forestry practices (Hamilton, 1941; Van Zyll de Jong, 1983; Carey and Harrington, 2001; Ford and Rodrigue, 2001; Matthews et al., 2009). Shrews have high nutritional and moisture requirements; therefore shrews may be sensitive to forestry practices that change forest floor microhabitats and microclimate (Chew, 1951; Getz, 1961; Churchfield, 1990; Matthews et al., 2009). Specifically, shrew presence and abundance have been linked positively with canopy cover, leaf litter depth and cover, and available downed woody debris (Carey and Johnson, 1995; Lee, 1995; Butts and McComb, 2000; Hartling and Silva, 2004; Greenberg et al., 2007).
Short-term response of small mammals following oak regeneration silviculture treatments
2012, Forest Ecology and ManagementCitation Excerpt :Additionally, the combination of shelterwood harvests and prescribed fires could result in substantial changes to habitat conditions compared to either disturbance alone. For example, Matthews et al. (2009) caught 77% fewer southeastern shrews (S. longirostris) in fuel reduction treatments where the understory had been mechanically thinned followed by two prescribed burns (3 years apart) than in either mechanically thinned or twice burned treatments alone (Matthews et al., 2009). In the short-term, we detected no changes in mouse or shrew abundance or species richness following oak regeneration treatments.
Woodland salamander response to two prescribed fires in the central Appalachians
2010, Forest Ecology and ManagementNon-volant small mammals in landslides caused by the wenchuan earthquake in a fragmented forest of Sichuan, China
2015, Pakistan Journal of Zoology