Conference announcement (Blacksburg,Virginia)

Aquatic Ecosystem Health and Management Society

Conference announcement (Blacksburg, Virginia)     

A respiratory alert model for the Shenandoah Valley, Virginia, USA

Respiratory morbidity (particularly COPD and asthma) can be influenced by short-term weather fluctuations that affect air quality and lung function. We developed a model to evaluate meteorological conditions associated with respiratory hospital admissions in the Shenandoah Valley of Virginia, USA. We generated ensembles of classification trees based on six years of respiratory-related hospital admissions (64,620 cases) and a suite of 83 potential environmental predictor variables. As our goal was to identify short-term weather linkages to high admission periods, the dependent variable was formulated as a binary classification of five-day moving average respiratory admission departures from the seasonal mean value. Accounting for seasonality removed the long-term apparent inverse relationship between temperature and admissions. We generated eight total models specific to the northern and southern portions of the valley for each season. All eight models demonstrate predictive skill (mean odds ratio = 3.635) when evaluated using a randomization procedure. The predictor variables selected by the ensembling algorithm vary across models, and both meteorological and air quality variables are included. In general, the models indicate complex linkages between respiratory health and environmental conditions that may be difficult to identify using more traditional approaches.     

Macroinvertebrate Responses to Mitigative Liming of Dogway Fork, West Virginia

Dogway Fork, West Virginia, is a second–order stream affected by acid precipitation. One goal of the Acid Precipitation Mitigation Program was to determine if the composition or population levels of benthic macroinvertebrates were affected by limestone neutralization of the acidic waters (pH 4.5). Two techniques were used to determine any effects: seasonal Surber samples and in situ bioassays with selected genera. Prior to treatment, macroinvertebrate densities were low but represented a diverse group of acidtolerant taxa. During treatment, fewer macroinvertebrates were collected in the treated segment than in the untreated control. This appears to be a result of a number of factors, including substrate, flows, drift, fish predation, accumulation of limestone fines, and changes in water chemistry. Bioassays suggest that the limestone fines were not directly detrimental to the organisms but may have limited available habitat in the mixing zone. Limestone treatment affected the species composition of Dogway Fork. During four years of treatment, several new acid-sensitive taxa were collected in the treated segment. Data suggest that, with continued treatment, populations of these taxa can be expected to increase.     

Epidemiology of raccoon rabies in Virginia, 1984 to 1989.

Geographical and temporal trends in reports of rabid raccoons (Procyon lotor) in Virginia were summarized for 1984 to 1989; 3,256 raccoons were submitted for rabies testing, of which 1,053 (32.3%) had rabies. Both the absolute number of rabid raccoons and the percent of rabid raccoons (number rabid divided by number submitted) were examined for seasonal and yearly trends. Geographically, the epidemic moved eastward and southward in the state. The seasonal trend showed bimodal peaks in late winter and early fall and a seasonal low in summer. The percent of rabies positive raccoons peaked 1 mo earlier than the absolute number of rabies positive raccoons. The peak in the number of rabies positive raccoons occurred in 1987, while the percent of rabies positive raccoons peaked in 1986. These trends were used to recommend timing and placement of oral vaccine as one strategy to control raccoon rabies in wildlife.     

Dendrochronological dating of the Graves Mill grist mill,Madison County,Virginia, USA

Historical dendroarchaeology uses annual tree-ring widths varied by climate to crossdate structures of potential historical significance. In the Southeastern U.S. Piedmont specifically, crossdating these structures can lead to a broader historical interpretation during and after the colonial era. Our study used historical dendroarchaeology to date the Graves Mill grist mill located in Madison County along the western edge of the Virginia Piedmont. The mill and mill site reflect a regional trend in eighteenth century land use as agriculture transitioned from tobacco to wheat production in response to demand from international markets, as well as the adverse impact of tobacco cultivation on piedmont soils. Mills in this region have also been subject to flooding events from storms, with events recorded in the colonial era to a recent record flood in 1995, as well as re-building with changes in mill technologies through time. In an effort to date this structure as part of its restoration, and to verify the repeatability of this dating, ring widths from six timbers from the upper stories were analyzed independently at tree-ring laboratories at the University of Tennessee, Knoxville and Rider University. Both laboratories identified an 1816 cutting date for these samples, supporting documentary evidence that the mill likely underwent modifications over time after it was initially constructed in the eighteenth century. The consistent crossdating of these samples highlights the usefulness of dendrochronology as a research tool in the Southeastern U.S. for interpreting historical structures and their surrounding historical context.     

Nontroglobitic Fishes in Bruffey-Hills Creek Cave, West Virginia, and other Caves Worldwide

Six species of fishes were tagged and released in September and November 1995 and on five dates between November 1998 and October 1999 inside Bruffey-Hills Creek Cave. Most of the tagged fishes were creek chub, Semotilus atromaculatus, and green sunfish, Lepomis cyanellus. The overall recapture rate was 2.6% as only three of 117 fishes were recaptured. Forty-nine days was the longest time of residence by two L. cyanellus and one S. atromaculatus, and movement of 83.4 m was observed only for the creek chub. Tag loss was confirmed as one factor in the low recapture rate. Nine species of fishes were collected in the cave, including Phoxinus oreas and Pimephales promelas, two species never collected in a cave. Most of the fishes were pigmented normally, but many creek chubs were depigmented and appeared white or pigmentless when first observed in the cave stream. Four species, Phoxinus oreas, Pimephales promelas, Ameiurus nebulosus, and Lepomis macrochirus, were collected for the first time in Bruffey-Hills Creek Cave and in the Bruffey and Hills creeks drainage. Although data from this study did not shed light on residence time of fishes in the cave, the consistent occurrence of epigean fishes in this cave was shown. A list of epigean fishes from caves worldwide was included along with a discussion of aspects of the ecology of epigean fishes in caves and of evolution of troglobitic fishes.     

Survival,cause-specific mortality,and population growth of white-tailed deer in western Virginia

Understanding the role of recruitment in population dynamics of white-tailed deer (Odocoileus virginianus) is important for management. In the central Appalachian Mountains, deer are part of a largely forested ecosystem that supports 3 carnivore species thought to be capable of influencing white-tailed deer recruitment: black bears (Urus americanus), coyotes (Canis latrans), and bobcats (Lynx rufus). Yet little is known about predation, how other environmental factors influence recruitment, or the importance of neonate survival to white-tailed deer population performance in the region. Our objectives were to identify causes of mortality for neonates, analyze effects of landscape attributes on survival of neonates, estimate survival rates for neonates and adult female white-tailed deer, and to model population growth trends based on current vital rates and hypothetical harvest and neonate survival scenarios. During 2019–2020, we captured 57 neonate deer in Bath County, Virginia, USA, by monitoring 38 pregnant females equipped with global positioning system collars and vaginal implant transmitters and by conducting transect searches for recently born neonates. We observed 37 neonate mortalities and identified cause of death using field and genetic evidence. Mortalities included 28 predation events and 9 deaths from other causes (e.g., abandonment, malnutrition, disease). Black bears accounted for 48.6% of neonate mortalities, and 64.2% of predation events (n = 18), followed by bobcats (n = 5) and coyotes (n = 3). Annual survival for adult female deer was 0.871 and neonate survival to 12 weeks old was 0.310. Elevation was a significant predictor of neonate survival; mortality risk increased 20% for every 100-m increase in elevation. Models of annual population growth using observed vital rates predicted an increasing population (λ = 1.10). A 10% increase in female harvest would still result in a potential population increase of 2% (λ = 1.02), but a 20% increase in harvest rate would result in a potential 7% decline (λ = 0.93). Neonate survival was higher near fertile valley bottoms and lower along forested ridges characterized by shallow, infertile soils and limited edge or early successional forests. While predation, largely influenced by black bears, was the leading cause of neonate mortality and contributed to low neonate survival, we observed little evidence of population decline, and suggest there is opportunity for a modest increase in harvest of female deer.     

Species composition,distribution, and abundance of oligochaetes in the Kanawha River,West Virginia

Species composition, distribution, and abundance of oligochaetes in the Kanawha River, West Virginia, were investigated. Eighteen taxa of oligochaetes including 7 tubificids, 8 naidids, and representatives of the families Enchytraeidae, Lumbriculidae, and Aelosomatidae were collected. While most of the species collected are cosmopolitan, Pristina synclites and Stephensoniana sp. previously reported only from Asia and Africa were collected in the Kanawha. Other peculiarities of the Kanawha oligochaete fauna included the common occurrence of specimens of Limnodrilus cervix and Limnodrilus hoffmeisteri with atypical penis sheaths. The dominant and most widely distributed of the Kanawha River oligochaetes were immature tubificids lacking capilliform chaetae, Branchiura sowerbyi, Dero cf. obtusa, Limnodrilus hoffmeisteri, and Aulodrilus pigueti.Oligochaete densities ranged from 401–2403 individuals/m² in areas presumed to be nonpolluted, to 1–671 individual/m² at sites with suspected toxicity. The highest density of oligochaetes (2835 individuals/m²) occurred at a site of organic enrichment.