Effects of Harvesting on Herbaceous Layer Diversity of a Central Appalachian Hardwood Forest

Clearcutting is a common harvesting practice in many eastern hardwood forests. Among the vegetation strata of these forests, the herbaceous layer is potentially the most sensitive in its response to harvest-mediated disturbances and has the highest species diversity. Thus, it is important to understand the response of herbaceous layer diversity to forest harvesting. Previous work on clearcut and mature stands at the Fernow Experimental Forest (FEF), West Virginia, has shown that, although, harvesting did not alter appreciably herbaceous layer cover, it influenced the relationship of cover to biotic and abiotic factors, such as tree density and soil nutrients, respectively. The purpose of this study was to examine the response of species diversity of the herbaceous layer to harvesting at FEF. Fifteen circular, 0.04 ha sample plots were established in each of four watersheds (60 plots in total) representing two stand age categories: two watersheds with 20 years even-age stands following clearcutting and two watersheds with mature second growth stands. All woody stems ≥2.5 cm diameter at breast height were identified, tallied, and measured for diameter. The herbaceous layer was sampled by identifying all vascular plants ≤1 m in height and estimating cover for each species in each of 10 (1 m2) circular sub-plots per sample plot (600 sub-plots total). Species diversity for each plot was calculated from herbaceous layer data using the ln-based Shannon Index (H′) equation. Ten stand and soil variables also were measured on each plot. Mean herbaceous layer cover for clearcut versus mature stands was 27.2±14.3% versus 20.2±8.1% (P\u3e0.05), respectively and mean H′ was 1.67±0.42 versus 1.55±0.48 (P\u3e0.05), respectively. Herbaceous layer diversity was negatively correlated with cation exchange capacity and extractable Ca and Mg in the mineral soil in clearcut stands. In contrast, herbaceous layer diversity was positively correlated with soil organic matter and clay content. Although, 20 years of recovery after clearcutting did not have significant effects on the species diversity of the herbaceous layer when examining stand age means alone, harvesting did appear to influence the spatial relationships between herbaceous layer diversity and biotic factors (e.g. tree density) and abiotic factors (e.g. soil nutrients)

The Ecological Significance of the Herbaceous Layer in Temperate Forest Ecosystems

Despite a growing awareness that the herbaceous layer serves a special role in maintaining the structure and function of forests, this stratum remainsan underappreciated aspect of forest ecosystems. In this article I review and synthesize information concerning the herb layer’s structure,composition, and dynamics to emphasize its role as an integral component of forest ecosystems. Because species diversity is highest in the herb layeramong all forest strata, forest biodiversity is largely a function of the herb-layer community. Competitive interactions within the herb layer candetermine the initial success of plants occupying higher strata, including the regeneration of dominant overstory tree species. Furthermore, the herblayer and the overstory can become linked through parallel responses to similar environmental gradients. These relationships between strata varyboth spatially and temporally. Because the herb layer responds sensitively to disturbance across broad spatial and temporal scales, its dynamics canprovide important information regarding the site characteristics of forests, including patterns of past land-use practices. Thus, the herb layer has asignificance that belies its diminutive stature

Spatial Variability in Soil Microbial Communities in a Nitrogen-Saturated Hardwood Forest Watershed

The long-term reference watershed (WS4), at Fernow Experimental Forest, West Virginia, displays symptoms of N saturation despite considerable spatial heterogeneity in soil properties, such as texture, N pools, and cycling rates. We identified a weathering gradient of three sites within WS4 by assessing differences in clay content across a common geologic substrate. Across these sites (LN, MN, and HN), NO3 production rates vary significantly (low, medium, and high nitrification, respectively) and are negatively related to clay content. It is unknown whether microbial communities vary across these sites and contribute to variability in NO3 production. This study characterized soil microbial communities along this gradient and assessed factors potentially important in explaining microbial composition. We sampled mineral soil from each of the sites, analyzing for moisture, pH, organic matter, extractable N, and microbial biomass and community composition via phospholipid fatty acid (PLFA) analysis. Analysis of variance and canonical correspondence analysis indicated that microbial community composition varied among sites, with a predominance of fungal markers (18:2n6 and 18:1n9c) at the most weathered LN site and Gram negative bacteria (18:1n7c) at the less weathered MN and HN sites. Accordingly, the fungi/bacteria ratio increased in the direction of LN plots in ordination space. Correlations between measured environmental parameters and PLFA data suggest that acidic conditions and low NO3 abundance at the LN site have selected for fungal dominance, although other important factors known to exert an influence on soil microbial communities, such as differences in plant community and clay and organic matter content, may also be playing a role in determining the observed patterns

Vrijeme do prvog EEG napadaja tijekom kontinuirane Video/EEG telemetrije

Correlation between time to first scalp EEG seizure during video/EEG telemetry and self-reported seizure frequency was determined in refractory epilepsy patients. Eighty two consecutive epilepsy patients were preoperatively evaluated, as part of a larger study, during their video/EEG monitoring at the Adult Epilepsy Center at Washington University. Self-reported seizure frequency, time to first seizure in the monitoring unit, and clinical variables of age, sex and seizure focus localization were analyzed. Mean age of the patients was 35±11 years and 54.9% were women. In 51 patients with temporal and 19 patients with extra temporal epilepsy, the mean time to first scalp EEG seizure was 44±48 h. Self-reported seizure frequency did not predict the time to first scalp EEG seizure in the seizure monitoring unit. The majority of patients had their first scalp EEG seizure during the first two days of video/EEG telemetry. Self-reported seizure frequency was a poor predictor of time to first scalp EEG seizure. This finding suggests that patients with less frequent self-reported seizure rates should also be considered as good candidates for further evaluation, including scalp and intracranial video/EEG telemetry.Određivala se je korelacija između vremena do prvog napadaja kod EEG vlasišta tijekom Video/EEG telemetrije i učestalosti napadaja koju su navodili sami bolesnici s refraktornom epilepsijom. Prijeoperacijski su obrađena 82 uzastopna bolesnika s epilepsijom, kao dio veće studije, tijekom njihova Video/EEG praćenja u Centru za epilepsiju odraslih pri Sveučilištu u Washingtonu. Analizirana je učestalost napadaja koju su naveli sami bolesnici, vrijeme do prvog napadaja u kabinetu za praćenje, te kliničke varijable za dob, spol i žarišnu lokalizaciju napadaja. Srednja dob bolesnika bila je 35±11 godina, a 54,9% bile su žene. U 51 bolesnika s temporalnom i 19 bolesnika s ekstratemporalnom epilepsijom srednje vrijeme do prvog napadaja na EEG bilo je 44±48 h. Učestalost napadaja koju su navodili sami bolesnici nije predskazala vrijeme do prvog napadaja kod EEG telemetrije. U većine bolesnika prvi je napadaj na EEG nastupio tijekom prva dva dana Video/EEG telemetrije. Učestalost napadaja koju su navodili bolesnici bila je loš predskazatelj vremena do prvog napadaja na EEG. Ova studija ukazuje na to da bolesnike koji navode rjeđu učestalost napadaja treba također smatrati dobrim kandidatima za daljnju procjenu, uključujući Video/EEG telemetriju

Vrijeme do prvog EEG napadaja tijekom kontinuirane Video/EEG telemetrije

Correlation between time to first scalp EEG seizure during video/EEG telemetry and self-reported seizure frequency was determined in refractory epilepsy patients. Eighty two consecutive epilepsy patients were preoperatively evaluated, as part of a larger study, during their video/EEG monitoring at the Adult Epilepsy Center at Washington University. Self-reported seizure frequency, time to first seizure in the monitoring unit, and clinical variables of age, sex and seizure focus localization were analyzed. Mean age of the patients was 35±11 years and 54.9% were women. In 51 patients with temporal and 19 patients with extra temporal epilepsy, the mean time to first scalp EEG seizure was 44±48 h. Self-reported seizure frequency did not predict the time to first scalp EEG seizure in the seizure monitoring unit. The majority of patients had their first scalp EEG seizure during the first two days of video/EEG telemetry. Self-reported seizure frequency was a poor predictor of time to first scalp EEG seizure. This finding suggests that patients with less frequent self-reported seizure rates should also be considered as good candidates for further evaluation, including scalp and intracranial video/EEG telemetry.Određivala se je korelacija između vremena do prvog napadaja kod EEG vlasišta tijekom Video/EEG telemetrije i učestalosti napadaja koju su navodili sami bolesnici s refraktornom epilepsijom. Prijeoperacijski su obrađena 82 uzastopna bolesnika s epilepsijom, kao dio veće studije, tijekom njihova Video/EEG praćenja u Centru za epilepsiju odraslih pri Sveučilištu u Washingtonu. Analizirana je učestalost napadaja koju su naveli sami bolesnici, vrijeme do prvog napadaja u kabinetu za praćenje, te kliničke varijable za dob, spol i žarišnu lokalizaciju napadaja. Srednja dob bolesnika bila je 35±11 godina, a 54,9% bile su žene. U 51 bolesnika s temporalnom i 19 bolesnika s ekstratemporalnom epilepsijom srednje vrijeme do prvog napadaja na EEG bilo je 44±48 h. Učestalost napadaja koju su navodili sami bolesnici nije predskazala vrijeme do prvog napadaja kod EEG telemetrije. U većine bolesnika prvi je napadaj na EEG nastupio tijekom prva dva dana Video/EEG telemetrije. Učestalost napadaja koju su navodili bolesnici bila je loš predskazatelj vremena do prvog napadaja na EEG. Ova studija ukazuje na to da bolesnike koji navode rjeđu učestalost napadaja treba također smatrati dobrim kandidatima za daljnju procjenu, uključujući Video/EEG telemetriju

Clinical Predictors of Response to Depression Treatment in Persons with Epilepsy

Abstract: Background The literature on predictors of response to treatment of depression for persons with epilepsy is limited. This study examined predictors of response to treatment of major depression disorder (MDD) by cognitive behavioral therapy (CBT) or Sertraline in Epilepsy patients. Methods: In the original two-site comparative effectiveness trial, 140 adult outpatients with active epilepsy and current major depressive disorder were randomly assigned to either sertraline (at a dose starting at 50 mg per day, titrating as needed at two-week intervals up to 200 mg per day) or weekly cognitive behavior therapy (CBT) for 16 weeks1. The primary outcome measure was the depression module of the MINI-International Neuropsychiatric Interview (M.I.N.I.). Secondary outcomes included the Quality of Life in Epilepsy Inventory (QOLIE)-89, seizure rates, the Adverse Events Profile (AEP), the Beck Depression Inventory II, and the M.I.N.I. Suicide Risk Module. A logistic regression model analysis was performed on patient clinical, psychosocial, and demographic variables previously identified as significantly significant in an attempt to develop a predictive model for positive MDD treatment response in persons with Epilepsy. Results: The variable that was predictive of MDD treatment response was the severity of the depression at baseline according to the Centers for Epidemiological Studies- Depression (CES-D) with a more severe baseline depression showing a lower response rate. Conclusion: The more severe MDD at baseline in epilepsy patients was shown to be predictive of a lower response to depression treatment with Sertraline or CBT in persons with Epilepsy

Spatial heterogeneity of soil nutrients and plant species in herb-dominated communities of contrasting land use

Recent interest in spatial pattern in terrestrial ecosystems has come from an awareness of theintimate relationship between spatial heterogeneity of soil resources and maintenance of plant species diversity. Soil and vegetation can vary spatially inresponse to several state factors of the system. In this study, we examined fine-scale spatial variability of soil nutrients and vascular plant species in contrasting herb-dominated communities (a pasture and an oldfield) to determine degree of spatial dependenceamong soil variables and plant community characteristics within these communities by sampling at 1-m intervals. Each site was divided into 25 1-m 2 plots. Mineral soil was sampled (2-cm diameter, 5-cm depth) from each of four 0.25-m2 quarters and combined into a single composite sample per plot. Soil organic matter was measured as loss-on-ignition. Extractable NH4 and NO3 were determined before and after laboratory incubation to determine potential net N mineralization and nitrification. Cations were analyzed using inductively coupled plasma emission spectrometry. Vegetation was assessed using estimated percent cover. Most soiland plant variables exhibited sharp contrasts betweenpasture and old-field sites, with the old field having significantly higher net N mineralization/nitrification, pH, Ca, Mg, Al, plant cover, and species diversity, richness, and evenness. Multiple regressions revealedthat all plant variables (species diversity, richness,evenness, and cover) were significantly related to soil characteristics (available nitrogen, organic matter,moisture, pH, Ca, and Mg) in the pasture; in the old field only cover was significantly related to soil characteristics (organic matter and moisture). Both sites contrasted sharply with respect to spatial pattern of soil variables, with the old field exhibiting a higher degree of spatial dependence. These results demonstrate that land-use practices can exert profound influence on spatial heterogeneity of both soil properties and vegetation in herb-dominated communities

Conservation and restoration of the Pinus palustris ecosystem

The well-documented decline of the Pinus palustris ecosystem has resulted from several anthropogenic influences, such as forest clearing (e.g. pine plantation forestry, agriculture) and urban development, both of which are closely related to increases in human populations. Other impacts have arisen from alterations in disturbance regimes responsible for maintaining the structure and function of these ecosystems. Restoration and management of degraded pine savanna ecosystems is critical. Identification of ecological processes that determine the structure and function of the intact system are important because successful restoration efforts should be based on sound scientific understanding. In this paper, we introduce this special issue on the ecology, conservation, and restoration of the Pinus palustris ecosystem. Some global climate change scenarios have suggested that future changes may occur that alter frequency and severity of disturbances such as fires and hurricanes. Such changes may have large effects on pine stands, and ultimately entire Pinus palustris savanna ecosystems, thus presenting further challenges to their sustainable management

Spatial heterogeneity of soil nutrients and plant species in herb-dominated communities of contrasting land use

Recent interest in spatial pattern in terrestrial ecosystems has come from an awareness of theintimate relationship between spatial heterogeneity of soil resources and maintenance of plant species diversity. Soil and vegetation can vary spatially inresponse to several state factors of the system. In this study, we examined fine-scale spatial variability of soil nutrients and vascular plant species in contrasting herb-dominated communities (a pasture and an oldfield) to determine degree of spatial dependenceamong soil variables and plant community characteristics within these communities by sampling at 1-m intervals. Each site was divided into 25 1-m 2 plots. Mineral soil was sampled (2-cm diameter, 5-cm depth) from each of four 0.25-m2 quarters and combined into a single composite sample per plot. Soil organic matter was measured as loss-on-ignition. Extractable NH4 and NO3 were determined before and after laboratory incubation to determine potential net N mineralization and nitrification. Cations were analyzed using inductively coupled plasma emission spectrometry. Vegetation was assessed using estimated percent cover. Most soiland plant variables exhibited sharp contrasts betweenpasture and old-field sites, with the old field having significantly higher net N mineralization/nitrification, pH, Ca, Mg, Al, plant cover, and species diversity, richness, and evenness. Multiple regressions revealedthat all plant variables (species diversity, richness,evenness, and cover) were significantly related to soil characteristics (available nitrogen, organic matter,moisture, pH, Ca, and Mg) in the pasture; in the old field only cover was significantly related to soil characteristics (organic matter and moisture). Both sites contrasted sharply with respect to spatial pattern of soil variables, with the old field exhibiting a higher degree of spatial dependence. These results demonstrate that land-use practices can exert profound influence on spatial heterogeneity of both soil properties and vegetation in herb-dominated communities