Global climate change impacts can already be tracked in many physical and biological systems; in particular, terrestrial ecosystems provide a consistent picture of observed changes. One of the preferred indicators is phenology, the science of natural recurring events, as their recorded dates provide a high-temporal resolution of ongoing changes. Thus, numerous analyses have demonstrated an earlier onset of spring events for mid and higher latitudes and a lengthening of the growing season. However, published single-site or single-species studies are particularly open to suspicion of being biased towards predominantly reporting climate change-induced impacts. No comprehensive study or meta-analysis has so far examined the possible lack of evidence for changes or shifts at sites where no temperature change is observed. We used an enormous systematic phenological network data set of more than 125 000 observational series of 542 plant and 19 animal species in 21 European countries . Our results showed that 78% of all leafing, flowering and fruiting records advanced (30% significantly) and only 3% were significantly delayed, whereas the signal of leaf colouring/fall is ambiguous. We conclude that previously published results of phenological changes were not biased by reporting or publication predisposition: the average advance of spring/summer was 2.5 days decade À1 in Europe. Our analysis of 254 mean national time series undoubtedly demonstrates that species' phenology is responsive to temperature of the preceding

No abstract

ABSTRACT:The main objectives of the study are to analyse the mean precipitation pattern in the Baltic countries (Estonia, Latvia, Lithuania) and the influence of local landscape factors on it, to derive a regionalization, i.e. select regions having coherent fluctuations in precipitation, and to analyse relationships between precipitation and characteristics of the large-scale atmospheric circulation. Monthly precipitation data from 123 stations in the Baltic countries from 1966 to 2005 are analysed in relation to 52 landscape variables and 13 circulation variables. The landscape variables characterize landscape around the meteorological stations: land cover, land surface elevation, distance from the sea coast, the proportion of water bodies and of forested area. Circulation is described using several circulation indices and frequencies of the main circulation types according to the Vangengeim-Girs and the Grosswetterlagen classifications. Maps depicting the mean annual and seasonal precipitation are created and analysed in the aspect of spatial and temporal autocorrelation. The Baltic Sea proved to be the main factor determining precipitation pattern in the study region. The presence of different precipitation zones parallel to the coastline is typical for the windward lowland region, whereas the belt of maximum precipitation is located at 10-60 km from the coast. Surface elevation is the second important factor causing higher precipitation on uplands. Rotated principal component analysis enabled to compose a regionalization of precipitation pattern in the Baltic countries. Four main precipitation regions having coherent fluctuations (south-western, south-eastern, north-eastern and north-western) are defined. Correlations between the variables of atmospheric circulation and precipitation are analysed. The intensity of westerlies is significantly positively correlated with the amount of winter precipitation, especially in the belt of maximum precipitation located at a moderate distance from the sea. Precipitation in the Baltic countries is less related to the meridional circulation types.

The river ice regime is considered a sensitive indicator of climate change and within this study long term changes (in case of River Daugava starting from 1530, but for other studied rivers starting from first half of twentieth century) river ice regimes in the Baltic region have been studied. The ice cover duration on the rivers (17 rivers) in the Baltic countries and Belarus has decreased during the recent decades. In addition to this, long term observational records of ice break on the rivers of the studied region exhibit a pattern of periodic changes in the intensity of ice regime. Both the ice regime and the seasonal river discharge are shown to be strongly influenced by large-scale atmospheric circulation processes over North Atlantic that manifests through close correlation with North Atlantic Oscillation index.

No abstract