Erigeron annuus (L.) Desf. 1804

Sennikov, Alexander N. & Lazkov, Georgy A., 2021, The first checklist of alien vascular plants of Kyrgyzstan, with new records and critical evaluation of earlier data. Contribution 1, Biodiversity Data Journal 9, pp. 75590-75590 : 75590

Erigeron annuus (L.) Desf. 1804

Erigeron annuus (L.) Desf., Tabl. École Bot.: 102 (1804) - Aster annuus L., Sp. Pl. 2: 875 (1753) - Phalacroloma annuum (L.) Dumort., Fl. Belg.: 67 (1827) - Stenactis annua (L.) Nees, Gen. Sp. Aster.: 273 (1832).

Erigeron annuus Erigeron ramosus var. septentrionalis Erigeron annuus subsp. septentrionalis Stenactis annua subsp. septentrionalis Stenactis septentrionalis Phalacroloma annuum subsp. septentrionale Phalacroloma septentrionale

Diagnosis

In the group of Erigeron annuus s.l., E. annuus s.str. can be distinguished by its narrower cauline leaves with less prominent teeth, white ray flowers and involucres with hairs 0.8-1.2(1.5) mm long ( Sennikov and Kurtto 2019).

Distribution

Native distribution

North America (Canada, USA, Mexico).

Secondary distribution

Neophyte in Europe and Asia. In Europe, this species belongs to the most widely distributed alien vascular plants ( Lambdon et al. 2008). It is also listed among the most dangerous invasive species in Russia ( Dgebuadze et al. 2018).

Distribution in Central Asia

Kyrgyzstan, Uzbekistan.

Tulaganova (1993) reported Erigeron annuus s.l. from Almaty City, Kazakhstan. This was the first record of this species complex published in Central Asia. A recent record from the same area, situated close to the Botanical Garden and the National University ( iNaturalist 2021), shows that this population belongs to E. lilacinus as defined by Sennikov and Kurtto (2019).

In Tajikistan, this species, broadly defined following Frey et al. (2003), was reported from Dushanbe City ( Nobis et al. 2017). The plants photographed in Dushanbe by Dzhamshed Sattarov ( Plantarium 2021) have broad and coarsely dentate leaves and lilac flowers and, therefore, correspond to E. lilacinus ( Sennikov and Kurtto 2019).

Our new reports of this species (as currently defined) provide its first reliable records from Central Asia and extend its known secondary distribution to Kyrgyzstan and Uzbekistan.

In Uzbekistan, the species was first recorded by Tulkin Tillaev in 2020 from meadows in Ulug'bek District of Tashkent City ( Plantarium 2021). It forms a large population, which is apparently established.

Distribution in Kyrgyzstan

Western Tian-Shan (Fig. 5 ).

We found large populations of this species along the Avletim River (downstream from Avletim Village) and the Kojo-Ata River (downstream from Arkyt Village up to the Avletim River), including the vicinities of Arkyt Village. The populations around Arkyt (Fig. 6 ) have been observed during multiple visits since 2009. In this area, the species is connected with managed meadows (used for hay-making) but occurs extensively also on natural meadows along river sides.

As observed in the Caucasus, the invasion of Erigeron annuus may be highly aggressive on hay meadows and pastures of mountainous areas up to high elevations ( Pshegusov et al. 2020), and its further spread in Kyrgyzstan is therefore expected.

In the Sary-Chelek Nature Reserve, the species was found at elevations between 1000 and 1300 m, which are optimal for grasslands and forb meadows. The upper altitudinal limit observed at 1000 a.s.l. in the Swiss Alps in Europe ( Trtikova et al. 2010) is not valid in the Tian-Shan Mountains.

Ecology

Prairies and meadows in the native distribution area; managed meadows and ruderal places in the secondary distribution area. In Europe, this species belongs to the three most invasive neophytes occurring in natural and semi-natural grasslands ( Axmanová et al. 2021).

Biology

Annual or biennial. The species is characterised by very high seed productivity ( Stratton 1991) and easily colonises bare or disturbed grounds ( Stratton 1992). The seeds of Erigeron annuus were found to inhibit the development of seedlings of some other species ( Oh et al. 2002, Kudryavtseva et al. 2020).

Notes

The taxonomy, nomenclature, native and secondary distributions of species-level taxa in the complex of Erigeron annuus s.l. were resolved by Sennikov and Kurtto (2019).

Introduction to Kyrgyzstan

Period of introduction

Neophyte.

The species was first recorded in the wild in 2009 and had apparently arrived during the period of the independence of Kyrgyzstan, in the 2000s.

Pathways of introduction

Transport - Contaminant: Contaminated bait.

Similarly to Bunias orientalis , this species was seemingly introduced to the Sary-Chelek Nature Reserve as a contaminant of imported fodder from Russia, where it is known as one of the most widely distributed invasive plants ( Vinogradova et al. 2018). This species is highly favoured by mowing, which promotes its local invasion ( Song et al. 2018); that was apparently the case in Kyrgyzstan, where it was unintentionally dispersed by the inhabitants of Arkyt Village, who used the territory intensely for hay-making (Sennikov & Lazkov, pers. obs.).

Further dispersal occurs by wind and human management.

Invasion status

Fully naturalised, highly invasive.

Evidence of impact

Agriculture - moderate impact (weed of pastures and hay-making meadows, with limited distribution; not recorded in crop production areas). Native ecosystems - moderate impact (invading riversides, grasslands and other meadows, with limited distribution). Urban areas - minor impact (very rare ruderal plant in populated places, including private gardens).

Trend

Increasing (observed).

Figures

Figure 5. Distribution of Erigeron annuus (dots) and E. lilacinus (triangles) in Kyrgyzstan.

Figure 6. Large stands of Erigeron annuus s. str. in the Sary-Chelek Nature Reserve (photo by A. Sennikov, 12 July 2016).