Ronald E. Thill

Tree Roosting by Male and Female Eastern Pipistrelles in a Forested Landscape

Abstract Little information has been published on selection of tree roosts by eastern pipistrelles (Perimyotis subflavus) in forested environments, and no radiotelemetry-based studies have been conducted on males in forested settings. Therefore, we used radiotelemetry to characterize summer roost selection by 21 male (33 roosts) and 7 female (14 roosts) eastern pipistrelles during 6 years in a forested region of the Ouachita Mountains of Arkansas. All roosts were located in the vegetation of tree canopies; 50% of roosts of females and 91% of roosts of males were in dead leaves of deciduous trees. Three (43%) of 7 maternity colonies were in dead needles of large live pines (Pinus echinata); this is the 1st documented use of pines by this species for roosting. Males selected tree sizes randomly but females selected trees that were larger (P < 0.05) than random. For males, 87% of roosts were in oaks (Quercus), and males roosted at sites with more midstory hardwoods, more large pines in the overstory, less canopy cover, and farther from the nearest trees than random locations. In a landscape offering a diversity of forest habitats, eastern pipistrelles during summer roosted mostly in leaves of oaks in mature (≥50-year-old) forest with a relatively complex structure and a hardwood component.

Long-Term Research at the USDA Forest Service's Experimental Forests and Ranges

Abstract The network of experimental forests and ranges administered by the US Department of Agriculture Forest Service consists of 77 properties that are representative of most forest cover types and many ecological regions in the nation. Established as early as 1908, these sites maintain exceptional, long-term databases on environmental dynamics and biotic responses. Early research at these sites focused on silviculture, ecosystem restoration, and watershed management. Over time, many of the properties have evolved into a functional network of ecological observatories through common large-scale, long-term experiments and other approaches. Collaboration with other institutions and research programs fosters intersite research and common procedures for managing and sharing data. Much current research in this network focuses on global change and interdisciplinary ecosystem studies at local to global scales. With this experience in developing networks and compiling records of environmental history, the experimental forests and ranges network can contribute greatly to formation of new networks of environmental observatories.

Scale-Dependent Effects of Landscape Structure and Composition on Diurnal Roost Selection by Forest Bats

Abstract Forest management affects the quality and availability of roost sites for forest-dwelling bats, but information on roost selection beyond the scale of individual forest stands is limited. We evaluated effects of topography (elevation, slope, and proximity of roads and streams), forest habitat class, and landscape patch configuration on selection of summer diurnal roosts by 6 species of forest-dwelling bats in a diverse forested landscape of the Ouachita Mountains, Arkansas, USA. Our objectives were to identify landscape attributes that potentially affect roost placement, determine whether commonalities exist among species in their response to landscape attributes, and evaluate the effects of scale. We modeled roost selection at 2 spatial scales (250- and 1,000-m radius around each roost). For each species, parameters included in models differed between the 2 scales, and there were no shared parameters for 2 species. Average coefficients of determination (R2) for small-scale models were generally higher than for large-scale models. Abundance of certain forest habitat classes were included more often than patch configuration or topography in differentiating roost from random locations, regardless of scale, and most species were more likely to roost in areas containing abundant thinned forest. Among topographic metrics, big brown bats (Eptesicus fuscus) were more likely to roost at higher elevations; roosts of big brown bats, northern long-eared bats (Myotis septentrionalis), and Seminole bats (Lasiurus seminolus) were influenced by slope; and big brown bats, evening bats (Nycticeius humeralis), and Seminole bats were more likely to roost closer to water than random. Northern long-eared bats and red bats (Lasiurus borealis) were more likely to roost closer to roads, whereas eastern pipistrelles (Perimyotis subflavus) were more likely to roost further from roads than random. Common parameters in most models included 1) positive associations with group selection (5 of 6 species) and thinned mature forest (4 species) at the small scale; 2) negative associations with unmanaged mixed pine–hardwood forest 50–99 years old at the large scale (4 species); 3) negative association with stands of immature pine 15–29 years old at the small scale (3 species); and 4) a positive association with largest patch index at the large scale (3 species). Our results suggest that, in a completely forested landscape, a variety of stand types, seral stages, and management conditions, varying in size and topographic location throughout the landscape, would likely provide the landscape components for roosting required to maintain a diverse community of forest bats in the Ouachita Mountains.

Grazing and Burning Impacts on Deer Diets on Lousiana Pine-Bluestem Range

Diets of 3-5 tame white-tailed deer (Odocoileus virginianus) on adjacent ungrazed and continuously grazed (35% herbage removal by late Oct) forested pastures were compared for forage-class use, botanical similarities, foraging selectivity and efficiency, and diet quality. Both pastures were divided into 3 burning subunits and burned in late February on a 3-year rotation. Botanical composition of diets differed between and within pastures, but forage-class use was similar except during winter, when deer selected more browse on ungrazed subunits. Grazing had no effect on dietary protein, phosphorus (P), or calcium (Ca) levels, but diets from ungrazed subunits were higher in digestibility (except during summer) and contained more uncommon plant taxa. Deer foraged more efficiently on grazed than on ungrazed subunits but were less efficient on recent than on older burns. Diets from 1st-year burns were higher in protein during spring and summer and higher in P during spring. J. WILDL. MANAGE. 51(4):873-880 Forested rangelands dominated by longleaf (Pinus palustris) or slash (P. elliottii) pine and bluestem grasses (Schizachyrium spp. and Andropogon spp.) occupy about 2 million ha of the southern Coastal Plain. Cattle have grazed southern forests since the 16th Century, but public land managers increasingly are under pressure from wildlife and environmental groups to curtail grazing due to its perceived detrimental effects on wildlife, especially white-tailed deer. Research to resolve this controversy began only recently (Thill and Martin 1986). Prescribed burning is an integral part of forest, wildlife, and cattle management in the South, This content downloaded from 157.55.39.27 on Wed, 07 Sep 2016 05:11:13 UTC All use subject to http://about.jstor.org/terms 874 CATTLE, BURNING, AND DEER DIETS * Thill et al. J. Wildl. Manage. 51(4):1987 but its effects on deer and cattle interactions have only recently been investigated (Thill 1984a, Thill and Martin 1986). Burning usually increases forage availability and nutrient content, and deer and cattle prefer to graze recent burns (Duvall and Whitaker 1964, Lay 1967). Late winter burning on a 3-year rotation is a common management practice for cattle. The abundant rainfall, high temperatures, and heavily leached, acid soils of the southern Coastal Plain produce an abundance of native forage of limited nutritional value. Many native forages are deficient in P all year (Blair et al. 1977) and adequate in protein only during spring for optimum deer growth (Short 1969, Thill and Morris 1985). The objective of this study was to determine effects of burning and grazing on deer diets. Specifically, we compared deer diet composition and nutritional data over a 3-year period from 3 rotationally burned subunits of a pasture receiving moderate yearlong grazing to those obtained on 3 subunits of an adjacent, rotationally burned, ungrazed pasture. Comparisons included forage-class use, botanical similarities, foraging efficiency, diet selectivity, and diet qual-

Deer and Cattle Diets on Heavily Grazed Pine-Bluestem Range

We studied dietary overlap between captive white-tailed deer (n = 3) (Odocotleus tir@nlanus) and cattle (n = 4) for 3 years on 2 rotationally burned, 54-ha longleaf pine (Pinus paZustris)-bluestem (Andropogon spp.) pastures in central Louisiana. A third of each pasture was burned each year in late February. One pasture was grazed heavily (61-77% herbage use) yearlong; the other was grazed heavily (SO-67% use) from mid-April to 1 November. Deer diets were dominated yearlong by a mixture of browse (49.3~83.2%) and forbs (11.2-47.1%). Cattle consumed mostly grasses during spring and summer and 60 and 40% browse and herbage, during fall and winter, respectively. Cattle consumed more herbage on first-year burns. Dietary overlap under heavy yearlong grazing averaged 25.8, 11.8, 26.0, and 30.7% during spring, summer, fall, and winter, respectively. Overlap under heavy seasonal grazing averaged 18.5, 7.4, and 22.6% during spring, summer, and fall, respectively. Diets of both animals were diverse and overlap generally resulted from sharing small amounts of many plant taxa. Except on recent burns during summer, dietary overlap under heavy yearlong grazing was comparable to that observed under moderate yearlong grazing at half the cattle stocking rate. Moderate grazing (40-50% herbage removal) of similar range from late spring through early fall should have little negative impact on deer forage availability. Grazing during late fall and winter reduces an already limited supply of deer forage by reducing availability of evergreen browse and herbaceous winter rosettes. J. WILDL. MANAGE. 53(3):540-548 Most woodland grazing in the southern United States has been confined to the longleaf-slash pine (P. elliottid) type. Bluestem grasses dominate the herbaceous understory on about 2 million ha of this forest type in southern portions of Louisiana, Mississippi, and Alabama, and in northwest Florida. Substantial knowledge on integrated forestry and cattle management has been gathered, but questions of compatibility between catt le and wildlife, especial ly deer, have st i rred considerable debate but resul ted in l i t t le research until recently (Mitchell 1980, Thill 1984, Thill and Martin 1986). Early studies of cattle diets in the South perta in pr imari ly to the sparse ly forested bluestem and wiregrass (Aristidu stricta) ranges that developed fol lowing extensive c learcutt ing ear l ier this century. The heavy yearlong grazing and frequent (often annual) burning common earlier this century reduced availability of woody plants , which are general ly a major component of deer diets in southern states (Lay 1969). Consequently, it is not surprising that browse was generally a minor component of cattle diets in early studies (Thill 1985). Most of this cut-over range has been replanted with pines, and woody plants are now relat ively abundant as a result of less burning and grazing. Thus, early studies of cattle diets are generally not applicable to present conditions. Recent research in southern Mississippi showed that browse contributed from 2.5% of cattle diets during summer to 21.4% during winter (Mitchell 1980) . Catt le diets on rotat ional ly burned, moderately grazed pine-bluestem range in central Louisiana averaged 40.9% browse during winter, and dietary overlap between cattle and deer ranged from 8.6% during summer to 34.7% during winter (Thill and Martin 1986). Prescr ibed burning is an integral component of southern range management because it increases forage quality and production and aids in distributing cattle. Deer receive similar forage benefits and prefer recent burns (Lay 1967). Our study was conducted in 2 phases of 3 years each to evaluate dietary overlap between deer and cattle under prescribed rotational burning and several grazing treatments. In phase I, we studied deer and cattle diets in a pasture grazed moderately yearlong and deer diets only in an adjacent ungrazed pasture (Thill and Martin 1986). We also evaluated phase I treatment effects on deer nutrition (Thill et al. 1987). The object ive of this study was to quantify deer and cattle dietary overlap on pine-bluestem range under heavy seasonal and heavy yearlong grazing. We also compare phase I and phase II data. We thank W. R. Thacker and R. D. Herrick for their assistance with data collection. D. C. Guynn, Jr., R. J. Warren, J. G. Kie, and D. L.

Plant Response to Soils, Site Preparation, and Initial Pine Planting Density

This study described the effects of soils, site preparation, and initial pine regeneration spacings on tree growth and the associated understory woody and herbaceous plant succession. Although Sawyer soils appeared more productive than Ruston soils before the harvest and regeneration treatments, woody and herbaceous plant differences were not apparent between the soils after regeneration. During the first 3 years after treatment, the mechanical site preparation method (shear-windrow-burn) reduced woody plant heights more than the underplant-release method; however, these height differences disappeared by the 6th year of post-treatment. Woody plant densities decreased initially, increased by the 6th year after treatment, and decreased to pretreatment levels by the 10th year. Herbage yields increased significantly after site preparation and pine regeneration through the 3rd year, decreased by the 6th year, and declined to levels below pretreatment by the 10th year. initial pine planting densities did not significantly influence the understory herbage yields during the first 10 years as a result of the confounding effects of the other woody plant growth.

Deer and cattle diet overlap on Louisiana pine-bluestem range

Seasonal diets of 5 cattle and 3-5 tame white-tailed deer (Odocoileus virginianus) on 3 subunits of a rotationally burned, continuously grazed longleaf pine (Pinus palustris)-bluestem (Andropogon spp.) range in Louisiana are compared with diets of these same deer on 3 similarly managed ungrazed subunits. Forage-class use by deer was more affected by burning than grazing, except during winter. Winter diets were affected by grazing, with deer selecting more herbage and less browse on grazed than on ungrazed sites. February burning reduced diet overlap substantially during spring. Within the 1st year after burning, diet overlap averaged 21.5, 11.2, 19.6, and 30.9% during spring, summer, fall, and winter, respectively. J. WILDL. MANAGE. 50(4):707-713 Woodland ranges dominated by longleaf and slash pines (P. elliottii) and bluestem grasses occupy about 2 million ha of the southern Coastal Plain. Timber production has been the primary use of these forests, but integrated management for timber, range, and wildlife is increasing. Guidelines have been developed for integrated forestry and cattle management (Byrd et al. 1984), but deer and cattle interactions only recently have been examined (Mitchell 1980, Thill 1984a). Many woody plants eaten by cattle are preferred deer foods (Goodrum and Reid 1955). However, cattle subsist primarily on grasses on longleaf-slash pine sites (Thill 1985), whereas deer consume mostly browse, fruits, forbs, and fungi (Lay 1969). Prescribed burning is an integral part of southern range management, but its effects on deer and cattle interactions have not been determined. One burning system consists of subdividing a pasture by firelines into >3 burning units and burning a different unit each year. Because cattle prefer the most recent burn, each burning unit receives varying degrees of use annually, depending on how recently it was burned (Duvall and Whitaker 1964). Our objectives were: (1) to determine the extent of seasonal diet overlap between deer and cattle as influenced by rotational burning and (2) to compare diets of tame deer on areas subjected to moderate yearlong cattle grazing and no cattle grazing for 25 years. W. R. Thacker, R. D. Herrick, S. D. Thacker, and many temporary employees assisted in raising deer and collecting data. W. P. Clary, J. C. Huntley, C. E. Lewis, and H. A. Pearson reviewed earlier drafts of the manuscript. STUDY AREAS The study was conducted on adjacent pastures on the Longleaf Tract, Palustris Experimental Forest, Kisatchie National Forest, 3.2 km north of Glenmora, Louisiana. Both pastures were divided by firelines into 3 burning subu its, each about 18 ha. Subunits are design ted EA, EB, and EC in the east (grazed) pasture and WA, WB, and WC in the west (ungrazed) pasture. Both pastures had been control-burned at 2-5-year intervals just prior to spring greenup since 1959. All subunits were burned in 1975. Subunit EB was burned in 1979 and all west pasture units and EC were burned in 1980. EA and WA were burned in 1981, EB and WB in 1982, and EC and WC in 1983, all in late February. Grazing pressure in the east unit had declined in recent years. Yearlong stocking from April 1971 through March 1974 at 1 cow/6-8 ha resulted in 66% herbage use and 10% browse use (Pearson 1976). Cattle were removed for nearly 4 years and then restocked from fall 1977 through 1980 at about 1 cow/19 ha. From 1981 through 1983, stocking was reduced for this study to about 1 cow/29 ha to achieve 35% average herbage use over the subunits. Because cattle prefer recent burns, use there averaged 46%, compared to 29 and 26% on the 2and 3 year-old burns, respectively. The west unit had not been grazed by livestock since 1956. The overstory on both units is a natural stand of 2nd-growth longleaf pine averaging 13.4 m2/ ha basal area (Thill 1984a). Current-year growth of hardwoods, shrubs, and vines to a height of 1.5 m averaged 401 and 468 kg/ha on grazed and ungrazed units, respectively. The fall her-

Deer and Cattle Diets on Louisiana Pine-Hardwood Sites

Analyse du regime alimentaire saisonnier et du chevauchement des niches ecologiques chez Odocoileus virginianus et le betail dans des forets reboisees ou coupees de Louisiane. Les resultats peuvent donner des indications quant au developpement de pratiques de pâture minimisant la competition entre cervides et betail

Understory plant response to site preparation and fertilization of loblolly and shortleaf pine forests.

In developing an improved understanding of the dynamics of understory plant composition and productivity in Coastal Plain forest ecosystems, we examined the influence of site preparation and phosphorus fertilization on the successional trends of shrubs and herbaceous plants growing on lands of widely ranging subsoil texture in Arkansas, Louisiana, and Texas which are managed for southern pine production. Burn-inject, chop-burn, chop-burn-disk, double-chop, shear-burn, shear-windrow, and shear-windrow-disk site preparation methods were applied in a completely randomized split-plot design to sites with subsoil textures consisting of loam, gravelly-clay, silt, silty-clay, and clay, both fertilized with 73.4 kg P/ha and unfertilized. Site preparation method, subsoil texture, and fertilization influenced production of paspalums and other forbs the first growing season following treatment, but no treatment combination affected plant groups in subsequent years. Total herbaceous production increased 24 to 35-fold over pretreatment levels the first growing season after treatment. While site preparation methods had little influence on herbaceous biomass, subsoil texture affected herbaceous production the first year after treatment, with loam subsoils being most productive. Although annual composites were the most abundant herbaceous group the first year after treatment, they were largely replaced by perennial grasses by the third post-treatment growing season. By the seventh growing season following treatment, herbaceous production declined on all subsoil textures with composition and yield approximating pretreatment estimates. Subsoil texture influenced shrub density only in the first and third growing seasons after treatment. During the first few years after site preparation, herbaceous production appeared inversely related to shrub density. In the first and third post-treatment growing seasons, fertilization significantly increased total herbaceous production and biomass of composites and legumes. But 7 years after application, total herbaceous production and biomass of bluestems, other grasses, and sedges was greater on unfertilized areas. The absence of differences among treatments by the seventh post-treatment growing season indicates an overall long-term similarity in the degree of disturbance caused by application of each method in this ecosystem.

Response of competing vegetation to site preparation on West Gulf Coastal Plain commercial forest land

This study was initiated to determine: (1) the response of saplings, shrubs, and herbaceous vegetation to various mechanical, chemical, and burning treatments on soils common throughout the West Gulf Coastal Plain of Louisiana, Arkansas, and Texas and (2) how fertilization affects understory vegetation response to site preparation on these soils.