نتایج جستجو برای: phenological phases
تعداد نتایج: 112694 فیلتر نتایج به سال:
Information on quality characteristics of forage species help the range managers to select a suitable grazing program that minimizes the damages to vegetation. Water Soluble Carbohydrates (WSC) -the main photosynthetic products- are stored in various plant parts and are more likely to be consumed when plants require them. In order to investigate the changes of WSC in distinguishable organs in t...
Vegetation phenology is the chronology of periodic phases of development. It constitutes an efficient bio-indicator of impacts of climate changes and a key parameter for understanding and modelling vegetation-climate interactions and their implications on carbon cycling. Numerous studies were devoted to the remote sensing of vegetation phenology. Most of these were carried out using data acquir...
Climate influences geographic differences of vegetation phenology through both contemporary and historical variability. The latter effect is embodied in vegetation heterogeneity underlain by spatially varied genotype and species compositions tied to climatic adaptation. Such long-term climatic effects are difficult to map and therefore often neglected in evaluating spatially explicit phenologic...
The present study classified global Ecosystem Functional Types (EFTs) derived from seasonal vegetation dynamics of the GIMMS3g NDVI time-series. Rotated Principal Component Analysis (PCA) was run on the derived phenological and productivity variables, which selected the Standing Biomass (approximation of Net Primary Productivity), the Cyclic Fraction (seasonal vegetation productivity), the Perm...
Phenological synchrony influences many ecological processes. Recent climate change has altered the synchrony of phenology, but little is known about the underlying mechanisms. Here using in situ phenological records from Europe, we found that the standard deviation (SD, as a measure of synchrony) of first leafing day (FLD) and the SD of first flowering day (FFD) among local plants were signific...
Many alpine and subalpine plant species exhibit phenological advancements in association with earlier snowmelt. While the phenology of some plant species does not advance beyond a threshold snowmelt date, the prevalence of such threshold phenological responses within plant communities is largely unknown. We therefore examined the shape of flowering phenology responses (linear versus nonlinear) ...
Climate change has resulted in major changes in the phenology--i.e. the timing of seasonal activities, such as flowering and bird migration--of some species but not others. These differential responses have been shown to result in ecological mismatches that can have negative fitness consequences. However, the ways in which climate change has shaped changes in biodiversity within and across comm...
BACKGROUND Studies aimed at investigating the influence of habitat change on species phenology. Studies that investigate people's perceptions of the phenology of certain species still area few; yet this approach is important for effective decision-making for conservation. The aim of this study was to investigate the phenology of Spondias tuberosa Arruda (Anacardiaceae), a native species of econ...
In this paper, a Bayesian change-point model was used to examine the phenological changes in the predominant crop producing states of U.S over a 33-year period (1981–2013). Changes of phenological observation were categorized into a no-change model and two change models. The change point and intensity of shifts were subsequently estimated under the selected change model. The experiments were co...
Phenological trends provide important indicators of environmental change and population dynamics. However, the use of untested population-level measures can lead to incorrect conclusions about phenological trends, particularly when changes in population structure or density are ignored. We used individual-based estimates of birth date and lactation duration of harbour seals (Phoca vitulina) to ...
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