The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Title from PDF of title page (University of Missouri--Columbia, viewed on October 16, 2009). Thesis advisor: Dr. Richard P. Guyette. Includes bibliographical references.

The Yellow Rail (Coturnicops noveboracensis) is a migratory nongame bird of high conservation priority throughout its entire range. The objectives of this study were: (1) assess Yellow Rail occupancy in the context of prescribed fire regime in pine savanna habitats of Mississippi and Alabama and (2) assess Yellow Rail habitat use in pine savanna habitats of coastal Mississippi. Yellow Rail occupancy decreased significantly with time since fire and increased with grassland patch size. Throughout the study area Yellow Rail maintained small (mean = 3.37 ha) home ranges aggregated within study areas, indicating suitable habitat may be limited. Yellow Rail used areas dominated by Aristida stricta and Carex spp. They used locations with lower woody percent cover, greater herbaceous height structure and lower frequency of trees than locations outside their home range. This research highlights the continued need to prioritize conservation and management of open grasslands and pine savanna habitats.

Identifying species occurrence in ecosystems of high conservation concern is especially important in the context of modern landscapes. This study investigated how stand-scale and landscape-scale factors affect priority birds associated with longleaf pine (Pinus palutris) ecosystems. Herein, I compared priority bird occupancy among 12 stand types throughout the historic range of longleaf pine. I found open pine stands positively influenced red-cockaded woodpecker (Picoides borealis) and Bachman’s sparrow (Peucaea aestivalis) occupancy, but were not significantly linked to northern bobwhite (Colinus virginianus) and brown-headed nuthatch (Sitta pusilla) occurrence. Landscape- and stand-scale factors affected red-cockaded woodpecker, Bachman’s sparrow, and brown-headed nuthatch occupancy. Northern bobwhite occupancy was influenced solely by landscape-scale factors. Red-cockaded woodpecker and Bachman’s sparrow were positively influenced by metrics associated with longleaf pine ecosystems suggesting they are effective indicator species. My analysis indicates that using this multi-scale approach is valuable to identifying areas on the landscape of conservation and restoration priority.

From the end of Reconstruction to the beginning of World War II, no other ecological change affected as great a part of the southern landscape as the loss of the longleaf pine from the southeastern coastal plain. This dissertation examines the causes and consequences of the species’ disappearance. In the span of just decades, lumber operations and naval stores producers descended upon longleaf pine woodlands with a voracious appetite that greatly contributed to the demise of the pine. However, as this dissertation argues, exploitation by the hands of the timber and turpentine industries was not the only agent that transformed the ecoregion. The development of American conservation and forestry, ironically, played a significant role in this process and contributed to the rise of a new southern forest, now stocked with another pine – the loblolly. By looking at the biologists, chemists, and foresters who studied the longleaf for the United States Department of Agriculture and various state agencies from the late nineteenth to the early twentieth century, this dissertation traces how forest sciences in the Gilded Age and Progressive Era shaped the modern ecology of the South. These sciences, too, were entangled in the social and political realities of Jim Crow. Researchers had to ensure that their measures conformed to a segregated society if conservation was to take root in southern woodlands. The conservation practices that federal and state agents put into place as forestry developed into an important and profitable science had profound impacts on not only the land but also those at the bottom of a racial caste system.

Modern forestry research and management emphasize infusing management practices with an understanding of natural disturbance regimes -- often called ecological forestry. Forestry practices emulating aspects of natural disturbance regimes are considered an effective tool to balance silvicultural and ecological objectives. Size, shape, and spatial distribution of canopy gaps formed by Hurricane Michael were studied across multiple site factors in a longleaf pine (Pinus palustris Mill.) woodland in southwest Georgia. No significant differences were observed in gap size or shape among landscape factors, but spatial distribution of gaps differed among landscape factors. The results observed highlight the ecological importance of the event and provide some insight into interactions at the landscape level. The implementation of a large, rapid, single disturbance event as a model for ecological silviculture may be more practically applied than disturbances such as lightning or insects which occur over longer timeframes.

Little information is available to nonindustrial-private forest (NIPF) owners regarding economic tradeoffs between managing pine plantations for timber production or wildlife habitat. Loblolly (Pinus taeda) and longleaf (Pinus palustris) pine plantations were modeled to quantify economic tradeoffs for competing management scenarios utilizing densities aimed at wildlife habitat or timber production in Mississippi. Models contained a range of site indices, planting densities, and rotation lengths for timber maximization and white-tailed deer (Odocoileus virginianus) or northern bobwhite (Colinus virginianus) habitat production. All management scenarios in loblolly plantations produced positive Land Expectation Values (LEVs), while one fifth of the management scenarios in longleaf plantations produced positive LEVs. Comparison to the regional hunting lease rate the compensatory lease rates from the study could be realized, making wildlife management as valuable as timber management. The results of this study will help landowners be more informed about economic tradeoffs when making management decisions on their property.

Root-feeding insects can have top-down influence on vegetative composition and ecosystem processes; however, they may respond to bottom-up factors such as soil resources, site productivity, and disturbance.  My research addressed the following questions: (1) Do disturbance (fire), vegetative composition, soil resources, and fine root standing mass influence the structure of root-feeding insect assemblages? (2) What types of roots do root-feeding insects eat, and do they forage selectively?  (3) Do root-feeding insects influence fine root productivity?  To address these questions, I studied root-feeding insect assemblages in longleaf pine wiregrass (Pinus palustris-Aristida stricta) ecosystems of southwestern Georgia, U.S.A.  On a random basis, study sites were burned at least every other year (B), or left unburned (UB) for about 9 years.  Fine root productivity and root-feeding insect abundances were sampled repeatedly across 54 random plots in UB and B sites.  In Chapter 2, I characterized spatial and temporal patterns of root-feeding insect abundance, understory plant composition, soil resource availability, and fine root standing mass within each plot.  Insect population densities were low overall, but abundance, patchiness, and diversity were greater in UB sites.  Abundance patterns were significantly related to vegetative composition.  In Chapter 3, I quantified the diet of root-feeding insects by measuring the natural abundance of carbon (C) and nitrogen (N) stable isotopes in insects and fine roots.  Using 13C abundance, I examined the contribution of warm season grass roots to insect diet, relative to the proportion of warm season grass roots within adjacent root standing crop samples; 15N abundance was used to detect omnivory.  Overall, insects appeared to be non-selective herbivores and omnivores that may alter foraging behavior to maintain a mixed diet (i.e. reducing or increasing warm season grass consumption when its abundance was high or low, respectively).  The extent of omnivory varied within and among taxa.  In Chapter 4, I estimated the top-down influence of root-feeding insects on fine root productivity by comparison of ingrowth cores with or without an insecticide treatment.  I detected a weak positive effect of herbivores on the productivity of non-grass fine roots (< 10% of fine root productivity). / Ph. D.

This study was conducted as a second part in the shear damage research project at Virginia Tech. The objectives were to verify the results obtained by Gallagher (1984) in the first study under normal mill operations as well as develop a method to compare and evaluate the extent of shear damage in relation to other defects present in southern pine lumber. This was accomplished through two sawmill studies and two kiln cart surveys performed in different geographic locations. Visible indicators such as stump-pull that are used to determine shear damage extent are often misleading. Stump-pull, used as a scaling deduction for shear damage, does not fully determine the extent of shear damage present. Shatter is often present in greater amounts over the cross section of the butt of the log. The recommendation of six inches of butt trim that was determined to minimize value losses in the first study is supported by the results obtained in this research. A trim of six inches removed 94 to 99 percent of shear damage in this study. Defects other than shear damage were present on dried and surfaced lumber. Drying checks and splits along with shake were often observed on the lumber ends. These defects often extend further up on the lumber ends, past the seven inch simulated trim. Shake was determined to be the limiting defect. Shatter, in the absence of shake, was determined to be limiting. Kiln cart surveys conducted at mills that utilize a large percentage of sheared logs can be an inexpensive and effective tool to enable mill personnel to determine the extent of shear damage in relation to other defects present on lumber ends based on green trim already taken. / Master of Science

Effective conservation requires reliable knowledge of habitat selection and data describing the target species’ response to prominent management techniques. Herein, I describe northern bobwhite breeding season resource selection in an intensively managed longleaf pine ecosystem and investigate the influence of post-fire succession and days-since-fire on bobwhite use of recently burned areas. I recorded bobwhite locations three times per week and surveyed recently burned areas twice daily. I found that bobwhite prefer natural pine woodlands burned the current year and pine plantations, hardwood pine forest, and shrub/scrub communities burned 1-2 years ago. Bobwhite avoided natural pine woodlands burned 1-2 years ago, recently burned (<1 year) shrub/scrub and hardwood-pine communities, urban/mowed areas, and hardwood forests. Few bobwhite used burned areas immediately following fire, but use of burned areas increased as post-fire green-up progressed. Days-since-fire was the best competing model to explain bobwhite use of recently burned areas.

Understanding the ecology of invasive species is vital to curb the homogenizing of ecosystems, yet the pollination mechanisms of the Chinese tallow tree (Triadica sebifera) in its introduced habitat remain ambiguous. This study examines self-pollination, wind pollination, and flower-visiting insects of tallow in a bottomland hardwood forest and Longleaf pine savannah in the U.S. Gulf South. These data suggest that self-pollination and airborne pollination are possible, but likely rare occurrences, although the possibility of apoxisis was not investigated. Seed production in exclusion experiments was significantly less than in open-pollinated flowers, and wind dispersal of tallow pollen dropped to essentially zero 8 meters from the source. Results show that tallow is primarily bee pollinated, with external pollen loads of Apis, Melissodes, and halictids visiting at similar rates, and Xylocopa species visiting less frequently. The researchers believe that to date, this is the first study of the pollination mechanisms of T. sebifera in its introduced range and recommend further study to understand the ecology of this destructive invasive species.