Search results for "HM"
showing 10 items of 10594 documents
Evaluating field-scale sampling methods for the estimation of mean plant densities of weeds
2000
The weed flora (comprising seven species) of a field continuously grown with soyabean was simulated for 4 years, using semivariograms established from previous field observations. Various sampling methods were applied and compared for accurately estimating mean plant densities, for differing weed species and years. The tested methods were based on (a) random selection wherein samples were chosen either entirely randomly, randomly with at least 10 or 20 m between samples, or randomly after stratifying the field; (b) systematic selection where samples were placed along diagonals or along zig-zagged lines across the field; (c) predicted Setaria viridis (L.) P. Beaux seedling maps which were us…
Patterns of movement of released female brown bears in the Cantabrian Mountains, northwestern Spain
2017
Between 2008 and 2013, 3 female brown bears (Ursus arctos; 2 cubs-of-the-year and 1 2-yr-old) were rescued, rehabilitated in captivity, radiotagged, and released back to the Cantabrian Mountains, northwestern Spain. We characterized their daily and seasonal movements post-release to gain insights into their movement strategies and the viability of bears released in human-dominated environments. The bears exhibited marked diurnal activity and were active throughout winter. Two bears demonstrated behaviors similar to those reported for wild bears, whereas one cub-of-the-year was recaptured after 21 days because she developed signs of habituation to humans.
Modulation of copper deficiency responses by diurnal and circadian rhythms in Arabidopsis thaliana
2015
Highlight Cyclic expression of copper transport and the responses to copper deficiency are integrated into the light and circadian–oscillator signalling in plants.
Chromosome numbers for the Italian flora: 11
2021
In this contribution, new chromosome data obtained on material collected in Italy are presented. It includes counts for Centaurea aegusae, Hieracium racemosum subsp. lucanum, H. australe subsp. australe, Lysimachia arvensis subsp. arvensis, Micromeria graeca subsp. graeca, and M. graeca subsp. consentina.
Modelling binary mixtures of herbicides in populations resistant to one of the components: evaluation for resistance management
2008
BACKGROUND: Herbicide mixtures are commonly proposed to delay the selection of herbicide resistance in susceptible populations (called the SM strategy). However, in practice, herbicide mixtures are often used when resistance to one of the two active ingredients has already been detected in the targeted population (called the RM strategy). It is doubtful whether such a practice can select against resistance, as the corresponding selection pressure is still exerted. As a consequence, the effect of mixtures on the evolution of an already detected resistance to one of the herbicides in the combination remains largely unexplored. In the present work, a simple model was developed to explore furth…
The mechanistic basis of demographic Allee effects: The search for mates
2017
In Focus: Berec, L., Kremer, A.M., Bernhauverova, V., & Drake, J.M. (2017). Density-dependent selection on mate-finding Allee effects. Journal of Animal Ecology, 87, 24-35. https://doi.org/10.1111/1365-2656.12662 In Focus: Shaw, A.K., Kokko, H., & Neubert, M.G. (2017). Details of mate finding drive dynamics of sex structured invasions. Journal of Animal Ecology, 87, 36-46. https://doi.org/10.1111/1365-2656.12658 Lowered population growth ability at low abundances is called the demographic Allee effect. The difficulty of finding mates in a sparse population is the best documented pathway through which a demographic Allee effect might arise. The articles in focus here aim to establish the mec…
Individual level consistency and correlations of fish spatial behaviour assessed from aquatic animal telemetry
2017
The potential for populations to undergo adaptive evolution depends on individual variation in traits under selection and how multiple traits are correlated. While fitness relates to the performance of animals in the wild, most of the research on evolutionary potential of behavioural traits has used captive or mesocosm settings, especially with aquatic organisms. We investigated the individual level consistency (personalities) and correlations (behavioural syndromes) of fitness-related behavioural traits displayed by a harvested marine fish in the natural environment, and the potential of such individual level behaviour to constrain adaptive evolution. For this, we acoustically tracked 303 …
Faster acquisition of symbiotic partner by common mycorrhizal networks in early plant life stage
2016
Arbuscular mycorrhizal (AM) fungi usually improve plant performance yet our knowledge about their effects on seed germination and early plant establishment is very limited. We performed a factorial greenhouse experiment where the seeds from four low Arctic cooccurring mycorrhizal herbs (Antennaria dioica, Campanula rotundifolia, Sibbaldia procumbens, and Solidago virgaurea) were germinated alone or in the vicinity of an adult Sibbaldia plant with or without AM fungi; given either as spores or being present in a common mycorrhizal network (CMN). Three different AM fungal species were examined to assess species-specific differences in symbiont acquisition rate. Out of the four plant species i…
Mechanisms of shrub encroachment into Northern Chihuahuan Desert grasslands and impacts of climate change investigated using a cellular automata model
2016
Arid and semiarid grasslands of southwestern North America have changed dramatically over the last 150 years as a result of woody plant encroachment. Overgrazing, reduced fire frequency, and climate change are known drivers of woody plant encroachment into grasslands. In this study, relatively sim- ple algorithms for encroachment factors (i.e., grazing, grassland fires, and seed dispersal by grazers) are proposed and implemented in the ecohydrological Cellular-Automata Tree Grass Shrub Simulator (CAT- GraSS). CATGraSS is used in a 7.3 km 2 rectangular domain located in central New Mexico along a zone of grassland to shrubland transition, where shrub encroachment is currently active. CATGraS…
Regional and Supra-Regional Coherence in Limnological Variabler
2009
Limnologists and water resources managers have traditionally perceived lakes as discrete geographical entities. This has resulted in a tendency for scientific lake studies to concentrate on lakes as individuals, with little connection either to each other or to large-scale driving forces. Since the 1990s, however, a shift in the prevailing paradigm has occurred, with lakes increasingly being seen as responding to regional, rather than local, driving forces. The seminal work on regional coherence in lake behaviour was that of Magnuson et al. (1990), who showed that many features of lakes within the same region respond coherently to drivers such as climate forcing and catchment processes. Fro…