Northwestern Arkansas Research Articles

Cultivar-To-Wild Population Introgression in Cucurbita pepo subsp. ovifera

Abstract Cultivar-to-wild population transgene flow occurs and can pose potential socio-ecological risks. In the USA, transgenic commercial squash cultivars [i.e., Cucurbita pepo subspecies ovifera var. ovifera] are cultivated in close proximity to cross-compatible wild squash taxa (i.e., vars. ozarkana and texana) that are native to the Americas. This association provides a unique opportunity for assessing cultivar-to-wild genetic introgression in this species. Thus, experiments were conducted using previously characterized random amplified polymorphic DNA (RAPD) to determine whether gene flow has occurred and whether alleles from putative introgression from cultivar-to-wild population exists in free-living populations. Free-living populations of C. pepo from the Ozark Plateau (southern Missouri, northwestern Arkansas, northeastern Oklahoma), Mississippi, Texas, Illinois, Kentucky, and Louisiana were examined using 21 RAPD primers (23 discriminatory bands). Banding morphotypes were useful for discriminat...

Potential value of operationally available and spatially distributed ensemble soil water estimates for agriculture

Summary The focus of this paper is to develop a methodology to answer the question: do the spatially distributed soil water estimates produced by operational distributed hydrologic models provide potential benefits for agriculture? The formulation quantifies the potential value through a cost–loss analysis, whereby cost for the farmer is associated with the decision to irrigate the field and loss is associated with the decision not to irrigate while damaging soil water deficits occur. Farmer decisions are made in view of the likelihood of damaging events as estimated by the ensemble distributed model simulations of soil water deficit. The ensemble simulations account for parametric and radar rainfall uncertainty. The application area for the economic value analysis is the farmland of the Illinois River watershed in northwestern Arkansas (mainly) and eastern Oklahoma, for which operational-quality distributed model input is available. The land is used to produce hay for feed. The analysis indicates that there is substantial potential economic value in using the ensemble soil water estimates to make decisions regarding irrigation within the watershed for the months of July, August and September, when severe soil water deficits may occur. The benefits are higher for lower cost–loss ratios and for higher yield plants. They exhibit considerable spatial variability within the watershed in agreement with the spatial variability of the incidence of soil water deficits and with the spatial variability of the ability of the ensemble model simulations to reproduce this variability. The results of this study warrant additional analysis of the economic value of distributed model simulations in other regions, different distributed models and for other types of crops. Consideration of forecasts in addition to simulations is also an important next step.

UNRAVELING THE EFFECTS OF SEX AND DISPERSAL: OZARK BIG-EARED BAT (CORYNORHINUS TOWNSENDII INGENS) CONSERVATION GENETICS

The Ozark big-eared bat (Corynorhinus townsendii ingens) is federally listed as endangered and is found in only a small number of caves in eastern Oklahoma and northwestern Arkansas. Previous studies suggested site fidelity of females to maternity caves; however, males are solitary most of the year, and thus specific information on their behavior and roosting patterns is lacking. Population genetic variation often provides the necessary data to make inferences about gene flow or mating behavior within that population. We used 2 types of molecular data: DNA sequences from the mitochondrial D loop and alleles at 5 microsatellite loci. Approximately 5% of the population, 24 males and 39 females (63 individuals), were sampled. No significant differentiation between 5 sites was present in nuclear microsatellite variation, but distribution of variation in maternally inherited markers differed among sites. This suggests limited dispersal of female Ozark big-eared bats and natal philopatry. Areas that experience local extinctions are unlikely to be recolonized by species that show strong site fidelity. These results provide a greater understanding of the population dynamics of Ozark big-eared bats and highlight the importance of cave protection relative to maintaining genetic integrity during recovery activities for this listed species.

INTEGRATED ECHO SOUNDER, GPS, AND GIS FOR RESERVOIR SEDIMENTATION STUDIES: EXAMPLES FROM TWO ARKANSAS LAKES1

ABSTRACT: Bathymetric and sedimentation surveys were conducted using a dual frequency (28/200 kHz) echo sounder system in two reservoirs (Lee Creek Reservoir and Lake Shepherd Springs) in the Ozark Plateau of northwestern Arkansas. Echo sounder survey data were merged within geographic information system (GIS) software to provide detailed visualization and analyses of current depths, pre‐impoundment topography, distribution, thickness, and volume estimates of lacustrine sediment, time averaged sediment accumulation rates, long term average annual sediment flux, and water storage capacity. Calculated long term average sediment accumulation rates were used to model sediment infilling and projected lifetimes of each reservoir. Results from echo sounder surveys and GIS analyses suggest that the Lee Creek Reservoir has a projected lifetime of approximately 500 years compared to a projected lifetime for Lake Shepherd Springs of approximately 3,000 years. Estimated differences in projected lifetimes of these reservoirs reflected differences in initial reservoir volume and long term average annual sediment flux from the respective watersheds related to watershed area, physiography, land cover, and land use. The universal soil loss equation (USLE) model generated sediment fluxes an order of magnitude larger from the watersheds of both reservoirs compared to the geophysical data estimates. This study demonstrated the utility of merging geophysical survey (echo sounder) data within a GIS as an aid to understanding patterns of reservoir sedimentation. These data and analyses also provide a baseline relevant to understanding sedimentation processes and are necessary for development of long term management plans for these reservoirs and their watersheds.

The Fayetteville Flora I: Upper Mississippian (middle Chesterian/lower Namurian A) plant assemblages of permineralized and compression remains from Arkansas, USA

The Fayetteville Formation of northwestern Arkansas contains a unique Upper Mississippian fossil flora with allochthonous permineralized plant remains recovered from offshore marine black shales and two coalified compression assemblages: one compression assemblage represents an autochthonous terrestrial/deltaic assemblage, and the other was recovered from near-shore strata. Fossil plants have been known from the Fayetteville Formation since at least 1937, and since that time, numerous individual taxa have been described, but no synopsis of the assemblages has been previously complied. This report summarizes previous reports and adds new data to produce a comprehensive floristic survey of this important fossil flora. The flora consists of 41 morphospecies: 19 permineralized species and 22 compression species that represent at least 15 whole plants. Lycopsid remains are the most numerous and pteridosperms are the most diverse. Sphenopsids are abundant but of low diversity (one genus) and ferns are rare. Lyginopteris royalii, Trivena arkansana, Megaloxylon wheelerae, Quaestora amplecta, Rhynchosperma quinnii, Chlamidostachys chesterianus, and Telangiopsis arkansanum are known only from these strata. The occurrence of Rhetinangium marks the first report of this genus in North America, and the occurrence of Medullosa is the oldest unequivocal evidence for this genus anywhere in the world.

Seasonal Occurrence and Distribution of Eggplant Flea Beetle, Epitrix fuscula Crocht (Coleoptera: Chrysomelidae) on Eggplant in Arkansas

The seasonal occurrence and distribution of the eggplant flea beetle (EFB), Epitrix fuscula Crotch, were monitored on eggplant in south central Arkansas during 1997, 1998, and 1999 and northwestern Arkansas during 1998 and 1999. In south central Arkansas, average numbers of EFB/plant were 11.9, 5.2 and 1.9 in 1997, 1998 and 1999, respectively. EFB numbers per plant decreased during the study in northwestern Arkansas from 13.3 in 1998 to 7.2 in 1999. This decline in numbers of EFB may be related to hot and dry weather during the spring and early summer months of the previous year and differences in transplant dates.Mapping the distribution of the foliar feeding by EFB indicated that the highest damage ratings (4 and 5) were recorded for eggplants on the north side of the south central field. Also, damage decreased rapidly on interior plants away from the north edge. First or edge plants in rows had damage ratings of 3.9; second and third plants averaged 2.6 and 2.1, respectively; and fourth to tenth plants had values less than 2.Additional insects encountered during eggplant sampling included the Colorado potato beetle, Leptinotarsa decemlineata (Say); the green tortoise beetle, Nuzonia pallidula (Boh.); the pepper weevil, Anthonomus eugenii Cano; Euphoria sepulcralis (Fabricius); the eggplant lace bug, Gargaphia solani Heidemann; and the corn earworm, Helicoverpa zea (Boddie). With the exception of sporadic damage by the Colorado potato beetle at the southern Arkansas location, damage from these insects was low.

Testosterone Cycles and Reproductive Energetics: Implications for Northern Range Limits of the Cottonmouth (Agkistrodon piscivorus leucostoma)

Abstract To assess the possibility of thermal effects on reproductive function as a range-limiting mechanism in cottonmouths, we investigated the effects of temperature/photoperiod regimes on monthly male testosterone levels in three groups. The first was a field group, the second was a lab control group that received natural temperature/photoperiod conditions, and the third was an experimental lab group that received temperature/photoperiod conditions of a region north of the current range limit. The field and lab control groups exhibited a single testosterone peak in August (34.4 and 14.1 ng ml−1, respectively) that coincided with observed reproductive activities in Northwestern Arkansas. The experimental group also exhibited a single peak (11.7 ng ml−1), but the peak was delayed by one month. We coupled energetic calculations with environmental temperature, the timing of reproductive events, and the time available for foraging to demonstrate how pre- and postcopulation reproductive failure may serve as...

STATUS OF ARKANSAS DARTER, ETHEOSTOMA CRAGINI, AND LEAST DARTER, E. MICROPERCA, IN ARKANSAS

In a 1983 survey of 50 spring-runs in northwestern Arkansas, Etheostoma cragini and E. microperca were each represented by only 5 populations. In summer and autumn 1997, we surveyed localities with historically documented populations and several additional spring-runs for presence of E. cragini and E. microperca to assess the current status of these species in Arkansas. Additionally, we documented local habitat attributes of each sample locality. We estimated population size of persistent populations in our surveys by mark-recapture method. Two populations of E. cragini had 546 (±214) and 79 (±60) individuals, and 2 populations of E. microperca had 1,341 (±349) and 129 (±56) individuals. Both darters inhabited small spring-run habitats with sand and silt substrate and some aquatic vegetation. These species are at risk of extirpation in Arkansas and should be considered for protection.

Hydraulic and Physical Properties of Stony Soils in a Small Watershed

The presence of rock fragments in soil layers can have a profound impact on measured hydraulic properties. Variation of surface soil hydraulic properties influences the amount, distribution, and routing of overland flow. The objective of this study was to assess the effect of rock fragments and soil texture on infiltration, hydraulic conductivity, and related physical properties in soils of a small watershed in northwestern Arkansas. Single‐ring and tension infiltrometer measurements at three pressure heads (h = −0.03, −0.06, and −0.12 m) were completed on the surface soil layer at 42 sites along three transects crossing the watershed. Upland (Nixa, loamy‐skeletal, siliceous, active, mesic Glossic Fragiudults) and side slope (Clarksville, loamy‐skeletal, siliceous, semiactive, mesic Typic Paleudults) soils had significantly less rock fragments, lower infiltration rates (i), and lower hydraulic conductivities (K) at and near saturation compared with the valley bottom soil (Razort, fine‐loamy, mixed, active, mesic Mollic Hapludalfs). Average infiltration rate at h = −0.03 m for all soils was only 9% of the ponded value suggesting that pores >1 mm in diameter dominated water flow under saturated conditions. At saturation, hydraulic properties tended to increase with rock fragment content while, at h = −0.12, the opposite was true. It is hypothesized that the source of rock fragments (weathering in place vs. colluvial and alluvial origin) and contact with the surrounding fine‐earth fraction influence water flow by affecting hydraulic continuity near fragment surfaces. These relatively subtle morphological factors may have a disproportionate impact on water flow under near‐saturation conditions in these soils.

Corporate Command Status in the Nonmetropolitan South, 1990-2001

Southeastern Geographer Vol. XXXXII, No. 2, November 2002, pp. 302-3 10 THE CHANGING SOUTH CORPORATE COMMAND STATUS IN THE NONMETROPOLITAN SOUTH, 1990-200 11 William W. Graves Few would argue that modern economic growth in the South has been centered in urban and suburban areas. The lack of a derelict industrial landscape, low labor costs and a rapid migration of human and financial capital into the region has allowed cities such as Dallas, Atlanta, Charlotte and Houston to rapidly rise to the top of the corporate urban hierarchy (Wheeler and Brown, 1985; Wheeler, 1992). This growth has bypassed the nonmetropolitan South, and job creation in this region has been driven by new branch-plant manufacturing facilities. The dependent (and mobile) nature ofthese jobs has acted to depress local wages and drain local capital; this branch-plant, corporate headquarters dichotomy has widened the divide between the prosperous-urban and peripheral-rural South (see Lyson,1989; Hartshorn and Walcott, 2000). Nearly all southern states have policies in place to encourage economic growth to diffuse into their nonmetropolitan peripheries. Until recently, the dominant policy tool used to encourage growth in the rural southern economy has been the idea of industrial succession; in other words, branch-plants attracted to the region's low costs would eventually attract service and technology employment and, given entrepreneurial good fortune, these facilities would eventually evolve into locally owned and controlled enterprises. Evidence supporting the validity of this process is widely available, and includes the following examples: Kanter's (1995) thorough examination of the Greenville-Spartanburg area's evolution from textile town to an internationally financed (and controlled) technology-oriented cluster ofmanufacturers , Charlotte's transformation from rail-hub and mill town into a national financial center (Graves, 2001), the transformation of rural northwestern Arkansas into a wealthy service industry enclave triggered by the growth of the Wal-Mart corporate headquarters (Hays, 2002), and the rapid migration ofcorporate headquarters which transformed much of the urban South into national command and control centers (Wheeler and Brown, 1985; Wheeler, 1992). In each case, development was said to be driven, in part, by a filtering down process or by local spillovers and entrepreneurial activity generated by existing branch-plants (see Erickson, 1976; Semple and Phipps 1982; Park and Wheeler, 1983). These transformations have stemmed the out-migration of financial and human capital from the South and, for the first Dr. Graves is an Assistant Professor ofGeography in the Department ofGeography and Earth Sciences, University ofNorth Carolina at Charlotte, Charlotte, NC 28223-0001. E-mail: bgraves@email.uncc.edu. CORPORATE COMMAND STATUS303 time, allowed for large-scale, local, profit accumulation (Borchert, 1978; Hartshorn and Walcott, 2000). Despite their successful application in the largest southern urban areas, the popularity ofdiffusionist growth theories, such as the industrial succession process discussed above, has waned. The near daily images of vacant textile mills (Lunan, 2002) are visual reminders of the relative absence ofjob growth and stagnant incomes in the rural South (Furuseth, 1992). This situation has led observers to suggest that the region faces structural impediments to this succession-driven process of development. One of these obstructions is the increased importance of local linkages and human capital caused by the transformation from a Fordist to a postFordist mode ofproduction (see Scott, 1988). Johnson (1997) posited that the isolation of the region which attracted branch-plants has prevented the development of the clusters necessary for modern industrial development. However, Johnson continued to note that the lack of clusters in the rural South does not impede the growth of all types of firms—not all businesses benefit equally from clustering; less innovative businesses such as retailers, natural resource firms and low-tech manufacturing are likely to reap greater benefits from the low wages associated with isolation. Other obstacles to economic development in the nonmetropolitan South include the lack of an innovation infrastructure (Feldman and Florida, 1994), primarily human and financial capital. The absence of these resources is a concern of all firms, but these disadvantages will have less impact on relatively "low-tech" firms such as retail and mass production. The obstacles to the development of high-tech firms in the South suggest that the most likely evolution of...

Use of Small Caves by Ozark Big-eared Bats(Corynorhinus townsendii ingens) in Arkansas

Abstract The Ozark big-eared bat (Corynorhinus townsendii ingens) is an endangered subspecies currently known only from small populations in Arkansas and Oklahoma. Between October 1998 and May 2000 we surveyed 93 small caves in northwestern Arkansas six times. During these surveys we encountered Ozark big-eared bats in 8–10 caves every season. During surveys in spring, summer and autumn, we encountered mainly lone individuals, while up to seven individuals were encountered together during winter surveys. Winter encounters were mainly in limestone caves, particularly those with vertical or near vertical sinkhole entrances, whereas caves with more varied characteristics were used in other seasons. Temperature may also have been a factor in choice of caves, with colder caves being preferred, especially in winter. Our data indicate that Ozark big-eared bats use many small caves in the study area. These caves should be protected, and other groups of small caves in the Ozarks should be surveyed for Ozark big-ea...

The Ozarks: Land and Life

The Ozarks: Land and Life. Second edition. By Milton D. Rafferty. (Fayetteville: University of Arkansas Press, 2001. Pp. xvi, 368. Illustrations, maps, notes, bibliography, index. $34.95, paper.) Sitting down with Milton Rafferty's The Ozarks: Land and Life is a little like visiting with an old friend after a few years' absence. It takes almost no time for the original admiration to return, and there are enough changes and new experiences to make a long visit worthwhile and enjoyable. Anyone who has delved into the field of Ozark studies (or anyone who has simply perused the shelves for informative reading on the region) during the past two decades already understands the impact and importance of Rafferty's work. Originally published in 1980 by the University of Oklahoma Press, The Ozarks: Land and Life was the first work to treat the geography, history, culture, and society of the region in a comprehensive manner. As such, it has served as an invaluable resource to countless students, scholars, and interested readers. Fortunately for those of us with an interest in the Ozarks, the University of Arkansas Press and Professor Rafferty decided to publish a revised second edition. The structure of the book is basically unchanged from the original, with chapters arranged thematically and with each divided by numerous subheadings. Most of the text from the original edition remains unchanged, though Rafferty has added updates or revisions of varying lengths in order to bring the story and analysis up to the end of the twentieth century. These updates and revisions are particularly useful when dealing with statistics (population, agricultural production, etc.) and when discussing crucial developments of the past twenty-odd years, such as the rise of Branson as a country music showcase and tourist magnet, intensified attention to environmental issues in the region, and the population and economic explosion of the northwestern Arkansas corridor from Fayetteville to Bella Vista. The original's unifying themes are still there, including Rafferty's smaller definition of the Ozark region that includes only territory west of the Mississippi. In cultural terms, Rafferty identifies traits that seem to best define the region: the Ozark region is rural (though obviously becoming less so all the time); its culture reflects the heritage of the upper South highland region (a heritage that persists in part due to the semi-arrested frontier nature of the Ozarks); its social system and relationships evince a stability rarely found in modern American society; and its residents manifest a strong sense of place as well as a conscious affiliation with the wider region. …

Seasonal water balance of an Ozark hillslope

Analysis of field water balance components provides information necessary to minimize the risk of offsite movement of contaminants from crop production practices or animal manure applications. The objective of this study was to determine the timing and amount of surface runoff and drainage from the root zone for a hillslope in the Ozark Highlands of US. A 0.4 ha watershed with slopes of 8–20% having tall fescue ( Festuca arundinacea Schreb.) cover was established in northwestern Arkansas (35°56′W, 93°51′N). Continuous measurements of water balance parameters were made from June 1997 to August 1998. Soil water drainage was estimated as the residual of weekly water balance calculations. Runoff occurred in response to three precipitation events in the winter of 1998 and totaled 30.6 mm of water or 2.6% of the 1185 mm of precipitation that fell at the site during the study period. Storms of comparable or greater intensity during other seasons failed to produce runoff, a result that was likely due to dry soil conditions and taller grass canopy. Drainage through the root zone totaled 117 mm and occurred primarily during an 83-day interval in the winter of 1998. The water balance was dominated by evaporation, which accounted for 91% (1080 mm) of the precipitation. Tall fescue was capable of sustaining relatively high evaporation rates between infrequent summer rains thereby dewatering the soil profile, which was not replenished until winter. Delaying spring animal manure applications in the Ozarks until evaporation has increased and the soil profile has begun to dry would decrease the risk of offsite transport of potential contaminants contained in the manure.

Lyginopteris royalii sp. nov. from the Upper Mississippian of North America

A new species of the seed fern Lyginopteris is described from a nodule in Upper Mississippian (middle Chesterian-Namurian A) shales of the Fayetteville Formation in northwestern Arkansas. The pyritized stem is 29 cm long and slightly compressed, with a diameter of about 11×5 mm, and shows seven diverging leaf bases. The primary xylem of the specimen is eustelic. Foliar bundles extend through five internodes before entering the rachis bases; they do not divide along their trajectory through the stem. Phyllotaxis of the specimen approaches 2/5. Longitudinally oriented sclerenchyma strands accompany the diverging foliar vascular bundles adaxially in the cortex, and are incorporated in the outer cortex above the level of foliar rachis divergence. In contrast to previously described Lyginopteris species, this species lacks capitate epidermal glands. A Lyginopteris type rachis with a paired vascular bundle is preserved in the same nodule. Coprolites probably produced by oribatid mites are present in different tissues of the stem. The study of the leaf trace divergence necessitated the use of a deformation model to help reconstruct the original position of the cauline bundles in the compressed stele. This occurrence of Lyginopteris confirms earlier reports of the genus from North America and emphasizes that it was not restricted to Western Europe.

Cats Surviving Natural Infection withCytauxzoon felis: 18 Cases (1997–1998)

Eighteen cats surviving natural infection withCytauxzoon feliswere identified. All cats came from a limited geographic area in northwestern Arkansas and northeastern Oklahoma. Clinical signs in most cats were similar to those described for cytauxzoonosis; however, 4 cats were asymptomatic. All cases were initially diagnosed by microscopic identification of signet ring‐shaped piroplasms in erythrocytes of peripheral blood smears. Four of 4 cats tested had detectable serum antibodies toC felis. Four different cats were positive by polymerase chain reaction (PCR). Partial sequencing of the PCR product from 1 cat revealed >99% homology with the reported sequence ofC felis. Repeated examination of blood smears from 12 cats revealed that the erythroparasitemia was generally persistent for the duration of follow‐up (3–154 days). Survival did not seem dependent on treatment, as only 1 cat was treated with a drug with potential antiprotozoal activity (imidocarb dipropionate), and 4 cats received no treatment. The findings of this study may indicate the existence of a less virulent strain ofC felis.

Microhabitat distribution of protostelids in temperate habitats in northwestern Arkansas

Protostelids are unicellular slime molds that belong in a monophyletic group, the Eumycetozoa. A standardized technique was developed for the study of protostelid communities from the leaf litter and aerial microhabitats of forests and grasslands in northwestern Arkansas. Protostelium mycophaga Olive and Stoian and Soliformovum irregularis (Olive and Stoian) Spiegel were more abundant in grasslands, while Schizoplasmodiopsis pseudoendospora Olive, Martin, and Stoian, Nematostelium ovatum (Olive and Stoian) Olive and Stoian, and Echinosteliopsis oligospora Reinhard and Olive were more abundant in forests. Some species of protostelids exhibited a preference for either the aerial microhabitat, e.g., P. mycophaga and Soliformovum irregularis, or the litter microhabitat, e.g., N. ovatum and Schizoplasmodiopsis pseudoendospora. Other species, including Cavostelium apophysatum Olive, Tychosporium arachisporum Spiegel, Moore, and Feldman, and Schizoplasmodium cavostelioides, were present in both microhabitats.Key words: ecology, mycetozoans, protoctists, slime molds.

Microhabitat distribution of protostelids in temperate habitats in northwestern Arkansas

Protostelids are unicellular slime molds that belong in a monophyletic group, the Eumycetozoa. A standardized technique was developed for the study of protostelid communities from the leaf litter and aerial microhabitats of forests and grasslands in northwestern Arkansas. Protostelium mycophaga Olive and Stoian and Soliformovum irregularis (Olive and Stoian) Spiegel were more abundant in grasslands, while Schizoplasmodiopsis pseudoendospora Olive, Martin, and Stoian, Nematostelium ovatum (Olive and Stoian) Olive and Stoian, and Echinosteliopsis oligospora Reinhard and Olive were more abundant in forests. Some species of protostelids exhibited a preference for either the aerial microhabitat, e.g., P. mycophaga and Soliformovum irregularis, or the litter microhabitat, e.g., N. ovatum and Schizoplasmodiopsis pseudoendospora. Other species, including Cavostelium apophysatum Olive, Tychosporium arachisporum Spiegel, Moore, and Feldman, and Schizoplasmodium cavostelioides, were present in both microhabitats.Key...

Cats surviving natural infection with Cytauxzoon felis: 18 cases (1997-1998).

Eighteen cats surviving natural infection with Cytauxzoon felis were identified. All cats came from a limited geographic area in northwestern Arkansas and northeastern Oklahoma. Clinical signs in most cats were similar to those described for cytauxzoonosis; however, 4 cats were asymptomatic. All cases were initially diagnosed by microscopic identification of signet ring-shaped piroplasms in erythrocytes of peripheral blood smears. Four of 4 cats tested had detectable serum antibodies to C felis. Four different cats were positive by polymerase chain reaction (PCR). Partial sequencing of the PCR product from 1 cat revealed >99% homology with the reported sequence of C felis. Repeated examination of blood smears from 12 cats revealed that the erythroparasitemia was generally persistent for the duration of follow-up (3-154 days). Survival did not seem dependent on treatment, as only 1 cat was treated with a drug with potential antiprotozoal activity (imidocarb dipropionate), and 4 cats received no treatment. The findings of this study may indicate the existence of a less virulent strain of C felis.

Short-Term Effects of Understory and Overstory Management on Breeding Birds in Arkansas Oak-Hickory Forests

Relatively little is known about the effects of uneven-aged forest management practices on eastern forest birds, despite the fact that such methods are now commonly practiced. In 1993-94, we studied the short-term effects of uneven-aged forest management on bird communities in oak-hickory forests of north-western Arkansas. We estimated bird abundance in mature forests and on managed plots receiving either a heavy cutting of understory vegetation (understory treatment) or a combination of both understory cutting and selective cutting in the forest overstory (full treatment). Two nesting guilds and 7 of 14 species with adequate sample size showed significant treatment effects. Ovenbirds (Seiurus aurocapillus), worm-eating warblers (Helmitheros vermivorus), Acadian flycatchers (Empidonax virescens), and the understory-nesting guild were most abundant in mature forest. Indigo buntings (Passerina cyanea), white-breasted nuthatches (Sitta carolinensis), and eastern wood-pewees (Contopus virens) were more abundant on full treatment plots. Tufted titmice (Baeolophus bicolor) were most abundant on mature forest and understory treatment plots. The canopy-nesting guild was most abundant on understory and full treatment plots. Our results suggest that if removal of understory vegetation was practiced widely in the Arkansas Ozarks as part of uneven-aged management, populations of some ground- and shrub-nesting forest interior species of birds could be negatively affected, whereas a few forest canopy and edge species may respond positively. Future research on this type of uneven-aged management should examine effects of removing varying amounts of understory vegetation on both forest interior bird populations and forest regeneration.

The earliest Gastrochaenolites (Early Pennsylvanian, Arkansas, USA): An upper Paleozoic bivalve boring?

Borings of the ichnogenus Gastrochaenolites have been found in limestone cobbles of the Morrowan (Early Pennsylvanian) Cane Hill Member of the Hale Formation in northwestern Arkansas. They were likely excavated by lithophagid bivalves, thus extending the earliest record of obligate bivalve boring back from the Triassic into the upper Paleozoic. These borings are herein referred to as G. anauchen n. ichnosp. Lithophagid borings may be rare in the upper Paleozoic because of the absence or scarcity of suitable substrates, such as scleractinian corals or carbonate hardgrounds. Additional upper Paleozoic bivalve borings will likely be discovered in other carbonate-rich rocky shore deposits.