Key message: Winter aconite flowering starts earlier in the spring

Assessment: Winter aconite (Eranthis hyemalis) is a critically endangered and strictly protected species with only a few records in Serbia. It grows on humus-rich, moderately fertile, well-drained soils in full sun or part shade. The early flowering, before another spring species, short vegetation period and summer dormancy, reflects its sub-Mediterranean origin and accompanying climate with most favourable conditions for plant development during the humid winter. Its life cycle is typical for many other Mediterranean geophytes, and is a limiting factor of distribution in continental areas where this species grows in adequate edaphic and climatic conditions. Flowering cycle and distribution pattern of winter aconite were studied in the Nature Reserve “Bagremara“. Observations were carried out from 1996 to 2018. In the conditions of Bagremara, flowering of winter aconite plants started in the middle of January and lasted until the middle of March, which is not in contrast to average data in other countries. Start of flowering period depends on the air temperature values during the winter months and the average annual air temperatures. This data is compared with official weather and climate information from nearby weather station in Bač. The average annual temperature increase in Serbia for the period 1996-2015 compared to the period 1961-1980 was 1.2 °C, and for the winter and spring period by 1.3 °C and 0.9 °C, respectively (Vuković et al., 2018) . However, the last 7 years (2012-2018) represent 7 hottest years recorded, with a mean anomaly of about 2 °C compared to the reference period (Đurđević et al., 2018). This change in temperature caused favourable thermal conditions for the longer duration of the vegetation period, during the period 2008-2017 in the lowlands, even in about a month longer than in the middle of the 20th century. Observations of the start date of growing season show advancing toward earlier dates, and it is expected to advance more in the future (MEP, 2017).

The observations of the blooming of the winter aconite (Eranthis hyemalis) in the Bagremara forest near Bačka Palanka were carried out relatively regularly since 1996 (observations from 2000, 2001, 2002, 2004, 2011, 2012 are missing, while data on the date of beginning of blooming are available for 16 years). The data were analysed for the period 1996-2017. The average date of blooming of winter aconite, obtained from all available data, is the 50th day from the beginning of year (19 February). For the period 1996-2006, the average day of blooming is the 68th day (9 March), and for the period 2007-2017 is the 38th day (7 February).

Literature:

Djurdjevic, V., Vukovic, A., Vujadinovic, M. (2018): Osmotrene promene klime u Srbiji i projekcije buduće klime na osnovu različitih scenarija budućih emisija, Izveštaj, Program Ujedinjenih nacija za razvoj.

MEP (2017): The Second National Communication on Climate Change under the United Nations Framework Convention on Climate Change, Ministry of Environmental Protection, Belgrade, 2017.

Vukovic, A. et al. (2018): Global warming impact on climate change in Serbia for the period 1961-2100, Thermal Science, vol. 22, pp. 2267-2280.

Panjković, B., Perić, R., Milenić, B (2019): Eranthis hyemalis (L.) Salisb. –indicator species of climate change. 13th Symposium on the Flora of Southeastern Serbia and Neighboring Regions. Stara planina Mt. 20 to 23 June 2019. Abstracts, 105-106.

Anomaly of average monthly air temperatures for January, February and MarchAnomaly of the date of winter aconite flowering with respect to the mean value for the entire period

Indicator Name: Climate Changes and flowering phenology of winter aconite

Institution/Author: Faculty of agriculture, University of Belgrade/Dr Ana Vuković, Provincial Institute for Nature Conservation, Novi Sad/dr Biljana Panjković,  Environmental Protection Agency/Slaviša Popović

Use and interpretation:

Key question(s) which indicator helps to answer  climate change impact in natural habitats in northern Serbia

Use of indicator: flowering date

Scale of appropriate use: national and regional

Potential for aggregation:

Meaning of upward or downward trends (“good or bad”)

Trend of flowering date is downward, meaning it is shifting toward earlier dates; negative consequence is possible damage from late spring frost

Possible reasons for upward or downward trends: temperature increase

Implications for biodiversity management of change in the indicator: The observation of the flowering of the winter aconite (Eranthis hyemalis) in the Bagremara forest near Bačka Palanka city was carried out relatively regularly since 1996 (observations for the years 2000, 2001, 2002, 2004, 2011, 2012 are absent, while for 16 years there are data on the date of beginning of flowering). The data were analysed for the period 1996-2017. The average date of flowering of winter aconite, obtained from all available data, is the 50th day from the beginning of the year (19th February). For the period 1996-2006, the average day of flowering is the 68th day (9th March), and for the period 2007-2017 is the 38th day (7th February).

The results show that positive anomalies in temperature correspond, in most of the years studied, to negative anomalies in the date of flowering. This means those warmer periods January-March correspond to the earlier date of flowering.

Units in which it is expressed:

date of flowering

Description of source data:

date of flowering in Begremar forest for each year since 1996; interpolated temperature data from available RHMSS stations

Calculation procedure:

Anomaly of flowering date with respect to its average values compared with temperature anomaly:

Anomaly of the date of winter aconite flowering with respect to the mean value for the entire period (green colour, left scale, anomalies in the number of days) and average temperature anomalies for January-March in the mean to the mean for the whole period (orange, right scale, in °C); brighter colours indicate negative deviations anomalies in temperature and positive in flowering date, and darker to positive anomalies of temperature and negative in flowering date; The mean values for the entire period 1996-2017 are calculated from data for years when there are also observations of the flowering of maize.

Anomaly of average monthly air temperatures for January, February and March with respect to the average monthly values for the whole period; the mean values for the entire period 1996-2017 are calculated from data for years when there are also observations of the flowering of maize.

Most effective forms of presentation:

graphs, narrative, example:

Anomaly of flowering date with respect to its average value (green, left axis), and anomaly of average temperature for January-March (orange, right axis) with respect to its average values for the while period (1996-2017); light colours indicate colder periods with later flowering and darker indicate warmer conditions with earlier dates of flowering.

Limits to usefulness and accuracy:

Measurements of meteorological parameters (at least 2m air temperature) desired to be on site

Updating the indicator:

Continued observations 

Closely related indicators     Flowering of Prunus laurocerasus related to Climate Changes

Additional information and comments

Table: Climate Changes and flowering phenology of winter aconite

Serbia