Search results for "PHENOLOGY"

Changes in vegetation spring dates in the second half of the twentieth century

2011

This study aims at estimating trends in spring phenology from vegetation index and air temperature at 2 m height. To this end, we have developed a methodology to infer spring phenological dates from Global Inventory Modeling and Mapping Studies GIMMS Normalized Difference Vegetation Index NDVI time-series, which are then extrapolated to the period 1948–2006 with the help of Reanalysis data, using its 2 m height air temperature parameter. First, yearly NDVI is fitted to a double-logistic function for the whole extent of the GIMMS database 1981–2003. This fitting procedure allows us to describe, on a yearly basis, the NDVI evolution for each pixel through the estimation of six parameters whic…

Impact of climate change on the timing of strawberry phenological processes in the Baltic States

2016

Climate change has been shown to impact aspects of agriculture and phenology. This study aims to quantify changes in the timing of garden strawberry blooms and harvests in the Baltic States using Regional Climate Models (RCMs). First, parameters for a strawberry phenology model based on the growing degree day (GDD) methodology were determined. Growing degree days were calculated using a modified sine wave method that estimates the diurnal temperature cycle from the daily maximum and minimum temperature. Model parameters include the base temperature and the required cumulative GDD sum, estimated from phenological and meteorological observations in Latvia for the years 2010–2013 via iterative…

Eco-physiological aspects of adaptation to seasonal environments : the latitudinal range expansion of the Colorado potato beetle across Europe

2013

Atmospheric brightening counteracts warming‐induced delays in autumn phenology of temperate trees in Europe

2021

Aim: Ongoing climate warming has been widely reported to delay autumn phenology, which in turn impacts carbon, water, energy and nutrient balances at regional and global scales. However, the underlying mechanisms of autumn phenology responses to climate change have not been fully elucidated. The aims of this study were to determine whether brightening that was defined as the increase of surface solar radiation and warming during recent decades affect autumn phenology in opposite directions and explore the underlying mechanisms. Location: Central Europe. Time period: 1950–2016. Major taxa studied: Four dominant European tree species in central Europe: Aesculus hippocastanum, Betula pendula, …

Microgastrinae (Hymenoptera: Braconidae) in the Forest State of Artikutza (Navarra: Spain): Diversity and Community Structure

2013

Microgastrinae is one of the largest subfamilies of the Braconidae with about 2,000 described species worldwide. These wasps are of enormous ecological interest due to their role in controlling the caterpillar populations. This study analyses diversity and community structure within the Microgastrinae in the Artikutza Forest, located in the Peñas de Aia Natural Park, western Pyrenees, Spain. The specimens were collected in two different habitats: mixed forest and beech forest. A total of 524 specimens, belonging to nine separate genera and 27 species were captured. Alpha, beta and gamma diversity were analyzed. Additionally, the relationship between Microgastrinae phenology and climatic con…

The Eurasian spoonbill Platalea leucorodia in Sicily between 1972 and 2018, distribution and ecology

2020

The observations of the Eurasian spoonbill made in Sicily between 1972 and 2018 were collected and analyzed. The presences, initially scarce and referred to a few sites, have consolidated over time, and gradually have affected an increasing number of sites. The observations were concentrated in the coastal salt pans and exsalt pans systems, secondarily in the mouths and in inland waters, below 100 m a.s.l.. The greatest number of Eurasian spoonbill was found in the migration period, both post and pre-reproductive; in the summer the lowest values. The average number of birds per flock, compared to subsequent years, from November to January did not vary significantly, while it was variable in…