A novel P106L mutation in EPSPS and an unknown mechanism(s) act additively to confer resistance to glyphosate in a South African Lolium rigidum population

Glyphosate resistance evolution in weeds is a growing problem in world agriculture. Here, we have investigated the mechanism(s) of glyphosate resistance in a Lolium rigidum population (DAG1) from South Africa. Nucleotide sequencing revealed the existence of at least three EPSPS homologues in the L. rigidum genome and identified a novel proline 106 to leucine substitution (P106L) in 52% DAG1 individuals. This mutation conferred a 1.7-fold resistance increase to glyphosate at the whole plant level. Additionally, a 3.1-fold resistance increase, not linked to metabolism or translocation, was estimated between wild-type P106-DAG1 and P106-STDS sensitive plants. Point accepted mutation analysis suggested that other amino acid substitutions at EPSPS position 106 are likely to be found in nature besides the P106/S/A/T/L point mutations reported to date. This study highlights the importance of minor mechanisms acting additively to confer significant levels of resistance to commercial field rates of glyphosate in weed populations subjected to high selection pressure.     

Social Heterogeneity and Community Forestry Processes: Reflections from Forest Users of Dhading District, Nepal

Community forestry has been characterized as a successful model of community-based forest governance in Nepal that shifts forest management and use rights to local users, often socially heterogeneous in caste, gender and wealth status. This heterogeneity forms the basis of social groups, which differ in their needs, priorities and perceptions regarding community forestry implementation processes. This paper explores the dynamics of three community forestry processes—users’ participation, institutional development, and decision-making and benefit-sharing—among forest user groups as perceived by three social groups of forest users—elite, women and disadvantaged—from eight community forests of Dhading district, Nepal, using qualitative and quantitative techniques. It is found that social groups have differing levels of perception about community forestry processes occurring in their user groups. In particular, social elites differ from women and disadvantaged members of the group in users’ participation in community forestry activities and institutional development of forest user groups. An important policy implication of the findings is that social inclusiveness is central to the effective implementation of community forestry processes, not only to safeguard its past successes but also to internalize the economic opportunities it poses through reducing deforestation and forest degradation in the future.     

The construction and evaluation of a device for mechanomyography in anaesthetized Göttingen minipigs

Objective To devise a method for assessing evoked muscle strength on nerve stimulation [mechanomyography (MMG)] in the anaesthetized minipig. Study design Prospective observational. Animals Sixty male Göttingen minipigs weighing 10.5–26.0 kg. Methods After cadaveric studies, a limb fixation device was constructed which allowed the twitch responses of the pelvic limb digital extensor muscles to be measured by force‐displacement transduction in response to supramaximal train‐of‐four (TOF) stimulation of the common peroneal nerve. The device was tested in 60 minipigs weighing 10.5–26.0 kg positioned in dorsal recumbency. Results The technique recorded the MMG of the common peroneal–pelvic limb digital extensor nerve‐muscle unit for up to 12 hours during which twitch height remained constant in 18 animals in which single twitch duration was <300–500 ms. In 42, in which twitch duration was >300–500 ms, 2 Hz nerve stimulation caused progressive baseline elevation (reverse fade) necessitating a modified signal capture method for TOF ratio (TOFR) computation. However, T1 was unaffected. The mean (range) of the TOFR in pigs with reverse fade was 1.2 (1.1–1.3). Conclusions and clinical relevance The technique allowed MMG recording in unparalysed pigs in response to TOF nerve stimulation and revealed a hitherto unreported complication of MMG monitoring using TOF in animals: reverse fade. This complicated TOFR calculation.     

Urbanization's impact on sustained yield management as perceived by forestry professionals in central New York

The urbanizing forested landscape in the United States is creating challenges for resource managers and land-use planners. Logistic regression models developed to assess urbanization's effect on forestland for the mid-Atlantic and southern states found that population density was the best predictor of reduced commercial harvest opportunity. We applied similar methodologies in central New York to assess urbanization's impact on sustained yield management. We surveyed professional foresters in a five-county area and asked them to rate the potential for sustained yield management by township. We utilized those expert opinions to develop a logistic regression model that predicted the probability of sustained yield management in central New York while exploring the factors that influence sustained yield management. We found that road density was the primary variable influencing the likelihood of sustained yield management in central New York. Population density, which is highly correlated with road density, also proved to be a strong determinant of sustained yield management. The results suggest that the potential for sustained yield management approaches 10% at a road density of 3 mi/mi², 50% at 2.5 mi/mi², and 90% at 2 mi/mi². The corresponding figures for population density were 150 people per square mile (ppsm), 75 ppsm and 25 ppsm, respectively. In addition, we determined that the probability of sustained yield management approaches 100% for a property that is approximately 30 acres and drops to 50% for a parcel that is between 15 and 20 acres. This study provides resource managers and land-use planners a guide in which to effectively gauge the cumulative effect of urbanization on the forest resource in central New York. Unlike other regions of the United States, central New York's growth pattern is characterized by stagnant population growth (declining in some places) combined with continued urbanization and low-density sprawl. Because growth patterns vary regionally, different indicators may be needed to accurately assess the urbanizing forested landscape across the United States.