The sensitivity of current and future forest managers to climate-induced changes in ecological processes

Climate vulnerability of managed forest ecosystems is not only determined by ecological processes but also influenced by the adaptive capacity of forest managers. To better understand adaptive behaviour, we conducted a questionnaire study among current and future forest managers (i.e. active managers and forestry students) in Austria. We found widespread belief in climate change (94.7 % of respondents), and no significant difference between current and future managers. Based on intended responses to climate-induced ecosystem changes, we distinguished four groups: highly sensitive managers (27.7 %), those mainly sensitive to changes in growth and regeneration processes (46.7 %), managers primarily sensitive to regeneration changes (11.2 %), and insensitive managers (14.4 %). Experiences and beliefs with regard to disturbance-related tree mortality were found to particularly influence a manager’s sensitivity to climate change. Our findings underline the importance of the social dimension of climate change adaptation, and suggest potentially strong adaptive feedbacks between ecosystems and their managers.

Electronic supplementary material

The online version of this article (doi:10.1007/s13280-015-0737-6) contains supplementary material, which is available to authorized users.     

Improved SWAT Model Performance With Time-Dynamic Voronoi Tessellation of Climatic Input Data in Southern Africa1

Andersson, Jafet C.M., Alexander J.B. Zehnder, Bernhard Wehrli, and Hong Yang, 2012. Improved SWAT Model Performance with Time-Dynamic Voronoi Tessellation of Climatic Input Data in Southern Africa. Journal of the American Water Resources Association (JAWRA) 48(3): 480-493. DOI: 10.1111/j.1752-1688.2011.00627.x Abstract: In this study, we compared two approaches to obtain climatic time series for the Soil and Water Assessment Tool (SWAT), namely the conventional centroid method and time-dynamic Voronoi tessellation, and assessed the performance of SWAT in simulating discharge and smallholder maize yields in Southern Africa. Climatic time series were estimated with each method. The Voronoi method utilized all available precipitation and temperature data, but the centroid method used only 14.5 and 82.5%, respectively. After centroid processing, sub-basin time series were on average 42 and 63% incomplete, respectively. After Voronoi processing, all time series were complete. SWAT was fed with each climate dataset. Each model setup was independently calibrated and validated against discharge and maize yield. Similar model performance was obtained with both methods for yield. The root mean squared error during calibration was 0.26 and 0.27 t ha⁻¹ for the centroid and Voronoi methods, respectively (p-value: 0.80). However, daily discharge simulations improved significantly with the Voronoi method. The coefficient of determination increased from 0.24 to 0.39 in the calibration period (p-value: 9.6 × 10⁻¹³) and from 0.41 to 0.48 in the validation period (p-value: 3.1 × 10⁻³). The Voronoi method improved the simulation of the river flow regime. The largest improvements were obtained in data scarce situations, at high spatial and temporal resolution, and where the centroid method performed the worst.     

Mineralization and Transfer Processes of <Superscript>14</Superscript>C-labeled Pesticides in Outdoor Lysimeters

A recently designed two-chamber-lysimeter-test-system allows the detailed investigation of degradation, transport and transfer processes of ¹⁴C-labeled substances in soil–plant–atmosphere-systems under outdoor conditions. With this test system it is feasible to distinguish between ¹⁴C-emissions from soil surfaces and ¹⁴C-emissions from plant surfaces in soil monoliths under real environmental conditions. Special soil humidity sensors allow the measurement of soil water content near to the soil surface, in 1 and 5 cm depth. The behavior of organic chemicals can be followed for a whole vegetation period and a mass balance for the applied chemical can be established. Some selected results of the herbicides isoproturon and glyphosate – using the two-chamber-lysimeter-test-system – are presented to demonstrate its applicability for the identification and quantification of the processes that govern pesticide behavior in soil–plant-systems. Mineralization of ¹⁴C-isoproturon was very different in four different soils; the mineralization capacity of the soils ranged from 2 to 60%. Leaching of isoproturon in general was very low, but depending on the soil type and environmental conditions isoproturon and its metabolites could be leached via preferential flow, especially shortly after application. For the herbicide ¹⁴C-glyphosate no accumulation of residues in the soil and no leaching of the residues to deeper soil layers could be observed after three applications. Glyphosate was rapidly degraded to AMPA in the soil. Glyphosate and AMPA were accumulated in soy bean nodules.     

Evaluating sustainable forest management strategies with the Analytic Network Process in a Pressure-State-Response framework

Nowadays forestry faces a complex management situation; the understanding of sustainable forest management (SFM) has gone far beyond the original meaning of sustainable yield of timber. SFM strategies should fulfil ecological, economic and social functions without causing damage to other ecosystems. In this understanding, forest management actions cannot be seen as isolated or mono-causal. In this case study, indicators for SFM are arranged in a Pressure-State-Response (PSR) framework at forest management unit level. This framework links pressures on the environment caused by human activities with changes of environmental state (condition) parameters. Forest management also responds to these changes by instituting environmental and economic measures to reduce pressures and restore natural resources. The Analytic Network Process (ANP) is utilized to evaluate the performance of four management strategies with regard to the PSR framework on SFM. Priorities of indicators and alternatives are modelled with the ANP resulting from the interconnections to other indicators and their respective cumulative importance. The approach allows for more detailed information on the network of human influences and their impacts on forest ecosystems and goes beyond the limitations of flat-dimensioned indicator sets.     

Impact of microcystin containing diets on physiological performance of Nile tilapia (Oreochromis niloticus) concerning detoxification

Nile tilapia (Oreochromis niloticus) were fed by diets supplemented with cyanobacteria containing in part the cyanotoxin microcystin-LR (MC-LR) to determine the potential impacts on detoxification. Four different diets were prepared based on a commercial diet: (1) control, (2) MC-5% (containing 5% dried Microcystis sp. biomass with 4.92 μg MC-LR g(-1) diet), (3) MC-20% (containing 20% dried Microcystis sp. biomass with 19.54 μg MC-LR g(-1) diet), and (4) Arthr-20% (containing 20% dried Arthrospira sp. biomass without MC-LR). Blood and liver samples were taken after one, 7, and 28 days and protein has been determined in plasma and liver. In the liver, impacts on detoxification were measured by glutathione-S-transferase (GST) activities and gene expression of multi drug resistance protein (MDRP). Plasma protein did not change between all four diets at any sampling time whereas liver protein was significantly elevated already after one day in Arthr-20% and after 28 days in both, MC-20% and Arthr-20%. Biochemical measurements of GST activities revealed no significant impact at any sampling time. In order to characterize the potential effect of MC-LR on MDRP, RT-qPCR method was established. However, as for GST activities no significant changes in MDRP gene expression have been observed. Thus, in summary, oral exposure of MC-LR containing cyanobacteria to Nile tilapia via feed ingestion did not impact significantly detoxification in liver concerning GST activities and MDRP expression despite biochemical composition concerning liver protein was significantly elevated by the diets containing 20% cyanobacteria biomass, regardless whether they contained MC-LR or not.     

Reproductive functions of wild fish as bioindicators of reproductive toxicants in the aquatic environment

Background, aim, and scope  

Impacts on the reproductive health of wild fish are thought to be suitable early-warning tools indicating contamination of surface waters with endocrine-disrupting compounds. Ecotoxicological assessment of these field observations depends on the availability of reliable biomarkers to enable a discrimination of natural variations of reproductive functions from anthropogenic impacts.     

Measurements of primary trace gases and NOY composition in Houston,Texas

Concentrations of CO, SO₂, NO, NO₂, and NO_Y were measured atop the University of Houston's Moody Tower supersite during the 2006 TexAQS-II Radical and Aerosol Measurement Project (TRAMP). The lowest concentrations of all primary and secondary species were observed in clean marine air in southerly flow. SO₂ concentrations were usually low, but increased dramatically in sporadic midday plumes advected from sources in the Houston Ship Channel (HSC), located NE of the site. Concentrations of CO and NO_x displayed large diurnal variations in keeping with their co-emission by mobile sources in the Houston Metropolitan Area (HMA). CO/NO_x emission ratios of 5.81 ± 0.94 were observed in the morning rush hour. Nighttime concentrations of NO_x (NO_x = NO + NO₂) and NO_Y (NO_Y = NO + NO₂ + NO₃ + HNO₃ + HONO + 21N₂O₅ + HO₂NO₂ + PANs + RONO₂ + p-NO₃^? + …) were highest in winds from the NNW-NE due to emission from mobile sources. Median ratios of NO_x/NO_Y were approximately 0.9 overnight, reflecting the persistence and/or generation of NO_Z (NO_Z = NO_Y ? NO_x) species in the nighttime Houston boundary layer, and approached unity in the morning rush hour. Daytime concentrations of NO_x and NO_Y were highest in winds from the HSC. NO_x/NO_Y ratios reached their minimum values (median ca 0.63) from 1300 to 1500 CST, near local solar noon, and air masses often retained enough NO_x to sustain additional O₃ formation farther downwind. HNO₃ and PANs comprised the dominant NO_Z species in the HMA, and on a median basis represented 17–20% and 12–15% of NO_Y, respectively, at midday. Concentrations of HNO₃, PANs, and NO_Z, and fractional contributions of these species to NO_Y, were at a maximum in NE flow, reflecting the source strength and reactivity of precursor emissions in the HSC. As a result, daytime O₃ concentrations were highest in air masses with HSC influence. Overall, our findings confirm the impact of the HSC as a dominant source region within the HMA. A comparison of total NO_Y measurements with the sum of measured NO_Y species (NO_Yi = NO_x + HNO₃ + PANs + HONO + p-NO₃^?) yielded excellent overall agreement during both day ([NO_Y](ppb) = ([NO_Yi](ppb)11.03 ± 0.16) ? 0.42; r² = 0.9933) and night ([NO_Y](ppb) = ([NO_Yi](ppb)11.01 ± 0.16) + 0.18; r² = 0.9975). A similar comparison between NO_Y–NO_x concentrations and the sum of NO_Zi (NO_Zi = HNO₃ + PANs + HONO + p-NO₃^?) yielded good overall agreement during the day ([NO_Z](ppb) = ([NO_Zi](ppb)11.01 ± 0.30) + 0.044 ppb; r² = 0.8527) and at night ([NO_Z](ppb) = ([NO_Zi](ppb)11.12 ± 0.69) + 0.16 ppb; r² = 0.6899). Median ratios of NO_Z/NO_Zi were near unity during daylight hours but increased to approximately 1.2 overnight, a difference of 0.15–0.50 ppb. Differences between NO_Z and NO_Zi rarely exceeded combined measurement uncertainties, and variations in NO_Z/NO_Zi ratios may have resulted solely from errors in conversion efficiencies of NO_Y species and changes in NO_Y composition. However, nighttime NO_Z/NO_Zi ratios and the magnitude of NO_Z ? NO_Zi differences were generally consistent with recent observations of ClNO₂ in the nocturnal Houston boundary layer.     

Half-lives of tetra-, penta-, hexa-, hepta-, and octachlorodibenzo-p-dioxin in rats,monkeys, and humans--a critical review

The elimination half-lives (t1/2) in Sprague-Dawley rats for 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), 1,2, 3,7,8-pentachlorodibenzo-p-dioxin (PeCDD), 1,2,3,4,7,8-hexachlorodibenzo-p-dioxin (HxCDD), 1,2,3,4,6,7,8-heptachlorodibenzo-p-dioxin (HpCDD) and 1,2,3,4,6,7,8,9-octachlorodibenzo-p-dioxin (OCDD) were estimated in long-term studies by Schlatter, Poiger and others. Furthermore, there are some published half-lives of TCDD in adult humans. The average half-life of TCDD in adult humans is approximately 2840 days, while in Sprague-Dawley rats the average t1/2 of TCDD is 19 days. The t1/2 of TCDD in humans is about 150 times that of rats. This factor was used to calculate the t1/2 values of the other polychlorinated dibenzo-p-dioxins (PCDDs) in humans from the rat data. Furthermore, the terminal t1/2 values of PCDDs in adult humans were calculated from the regression equation: logt1/2H = 1.34 logt1/2R + 1.25 which was recently established for 50 xenobiotics (t1/2H = terminal half-lives in days for humans, t1/2R = terminal half-lives in days for rats). The following terminal half-lives in adult humans were obtained: 12.6 years for 1,2,3,7,8-PeCDD, 26-45 years for 1,2,3,4,7,8-HxCDD, 80-102 years for 1,2,3,4,6,7,8-HpCDD and ca. 112-132 years for OCDD. These half-lives of PCDDs are critically compared with measured t1/2 values of PCDDs and other persistent organic pollutants in rats, monkeys and humans.     

The role of self-regulation in the context of driver distraction: A simulator study

Objective: There is considerable evidence for the negative effects of driver distraction on road safety. In many experimental studies, drivers have been primarily viewed as passive receivers of distraction. Thus, there is a lack of research on the mediating role of their self-regulatory behavior. The aim of the current study was to compare drivers' performance when engaged in a system-paced secondary task with a self-paced version of this task and how both differed from baseline driving performance without distraction.

Methods: Thirty-nine participants drove in a simulator while performing a secondary visual–manual task. One group of drivers had to work on this task in predefined situations under time pressure, whereas the other group was free to decide when to work on the secondary task (self-regulation group). Drivers' performance (e.g., lateral and longitudinal control, brake reaction times) was also compared with a baseline condition without any secondary task.

Results: For the system-paced secondary task, distraction was associated with high decrements in driving performance (especially in keeping the lateral position). No effects were found for the number of collisions, probably because of the lower driving speeds while distracted (compensatory behavior). For the self-regulation group, only small impairments in driving performance were found. Drivers engaged less in the secondary task during foreseeable demanding or critical driving situations.

Conclusions: Overall, drivers in the self-regulation group were able to anticipate the demands of different traffic situations and to adapt their engagement in the secondary task, so that only small impairments in driving performance occurred. Because in real traffic drivers are mostly free to decide when to engage in secondary tasks, it can be concluded that self-regulation should be considered in driver distraction research to ensure ecological validity.