Bidens frondosa L. 1753

Sennikov, Alexander & Lazkov, Georgy, 2022, The first checklist of alien vascular plants of Kyrgyzstan, with new records and critical evaluation of earlier data. Contribution 2, Biodiversity Data Journal 10, pp. 80804-80804 : 80804

Bidens frondosa L. 1753

Bidens frondosa L., Sp. Pl. 2: 832 (1753).

Bidens frondosa Bidens melanocarpa

Diagnosis

The species differs from Bidens tripartita L., which is common in Central Asia ( Nabiev 1993) and Kyrgyzstan ( Gorbunova 1965), in narrow, long-attenuated and narrowly petiolate leaflets, and in two (vs. 3-4) setae on the achenes. In the beginning of its invasion, it has been commonly confused with the latter species, thus obscuring the data on its actual occurrence.

Distribution

Native distribution

North America.

Secondary distribution

Europe, Asia (southern Siberia, Central Asia, Eastern Asia), Australia and New Zealand; sporadically also elsewhere.

In Europe, this species belongs to the most widely distributed alien vascular plants ( Lambdon et al. 2008). It also belongs to the most invasive plants in Russia ( Morozova and Vinogradova 2018) and Belarus ( Dzhus 2020).

Distribution in Central Asia

Kazakhstan, Kyrgyzstan, Tajikistan, Uzbekistan.

In Central Asia, the species was first recorded in a single locality on the south-eastern margin of Tashkent City, Uzbekistan, in 1990 ( Alexeev 1991). The species was found naturalised on irrigated grassland in newly developed city districts. By the beginning of the 2010s, the species was found commonly naturalised and invasive in agricultural areas of Uzbekistan ( Maltsev 2013).

In Kazakhstan, the species was first recorded in 2001 near Jänıbek in West Kazakhstan Region. This locality is situated immediately next to the Russian border, and the species was known from the southern Volga Region of Russia by that time ( Sukhorukov and Berezutsky 2000). Its current distribution seems to be quite wide, especially in agricultural areas of the north ( Plantarium 2021).

The species was first recorded in Kyrgyzstan by Lazkov et al. (2011), based on a single observation in Bishkek dated 2008. More data are reported in the present Contribution.

In Tajikistan, the species was first recorded from Dushanbe City and its vicinities in 2009, along roadside ditches ( Nobis and Nowak 2011). It was also found on rice fields near Hissar ( Nowak et al. 2013).

At present the species is naturalised in all these four countries. It is widely naturalised and invasive in Kazakhstan and Uzbekistan, but sparsely occurring and not yet invasive in Kyrgyzstan and Tajikistan.

Distribution in Kyrgyzstan

Western Tian-Shan, Northern Tian-Shan, Alay-Turkestan (Fig. 4 ).

Bidens frondosa was recorded in Bishkek in 2008, for the first time in Kyrgyzstan. Since then, small groups of the species have been observed in the city centre (Fig. 5 ). These occurrences are mostly ephemerous, not lasting long, but their regular re-appearance suggests that the invasion is continuous. The species was also observed established in the Botanical Garden, where it has found a suitable agricultural habitat and experiences little pressure from the environment.

During 2011-2020, we also observed small groups of B. frondosa in a few localities in the Fergana Depression, along the border with Uzbekistan. These previously unpublished records suggest that the species may be found elsewhere in the Depression because of its common naturalisation in Uzbekistan ( Maltsev 2013).

So far, all the localities are from altitudes between 650 and 1000 m above sea level, and the species shows no tendency to spread to the mountains.

Ecology

Sides of water bodies and flood plains in the native distribution area; river sides, wetlands, fields and ruderal places in the secondary distribution area.

Biology

Annual.

Bidens frondosa can grow taller than B. tripartita , producing more seeds, and, therefore, can outcompete the latter in agricultural and even native environments ( Danuso et al. 2012). This process has been observed in many countries, for example, Uzbekistan ( Maltsev 2013) and Russia ( Glazkova 2005).

Taxon discussion

The species is highly variable in certain characters. Bidens frondosa var. anomala was distinguished by the achenes antrorsely barbate along the whole margin, whereas achenes of the type variety are antrorsely barbate along the body but retrorsely barbate along the awns ( Sherff 1937, Verloove 2021). Both varieties were recorded in Uzbekistan ( Maltsev 2013). Variants with shorter and longer outer phyllaries were also observed in herbarium collections. These observations indicate a high genetic diversity and multiple events of the species' introduction to Central Asia, contrary to the hypothesis of Vinogradova et al. (2009) about a single founder effect in the East European invasion.

Notes

Rice has been commercially grown in the USA already in the 19th century ( Barrett and Seaman 1980). In the early 20th century, Bidens frondosa was a common weed of rice fields in California ( Kennedy 1923), although later works do not list this genus at all ( Barrett and Seaman 1980). The preference of B. frondosa for damp places accounts for its adaptability to rice fields; when introduced to Eastern Asia, the species became a noxious weed of rice fields in Korea ( Oh et al. 2007) and north-eastern China ( Zhu et al. 2020). It is also capable of infesting other crops, like maize, soybean and sugarbeet, in Italy ( Danuso et al. 2012) but may be lacking on fields in other countries like in Germany ( de Mol et al. 2015).

The attachment of Bidens frondosa seed to agricultural commodities is indicated by its numerous records at mills and railway stations ( Suominen 1979, Gudžinskas 1989; references in Glazkova 2005). Introduction with North American grain (maize, wheat or oat) was suggested in Finland ( Suominen 1979). Besides railways, sea ports may act as entrance points for the species ( Vorobiev 1954 and references in Glazkova 2005).

In Eastern Europe, the species was commonly recorded in many regions during the 1980s and 1990s (review in Glazkova 2005). However, the persons who recorded the species often noted its possible presence in the territory already for some considerable period, thus indicating that there was a significant backlog due to the superficial similarity of B. frondosa to the common East European native species B. tripartita . First records indicate the appearance of B. frondosa in towns and at railway stations as early as in 1955-1970 ( Glazkova 2005). As the early species' records show a clear relationship with the transportation of grain and accompanying commodities, we assume that its original appearance in Eastern Europe was connected with the transportation of imported agricultural goods.

This import may have a long and complex history. The first record of B. frondosa on the railway in Brest was dated 1955 and can be linked with the transportation of grains from Poland, which was noticeable since 1953 ( Mackie 1968). Further on, the species was recorded in Kirov Town, far away from possible sources in Europe, along a small river streaming through an industrial area with many railways ( Glazkova 2005). This record may be connected with the import of American grain that followed the drought of 1963 ( Zelenin 2014).

Due to the lack of early records in agricultural communities (on fields and field margins), we conclude that contamination of seed material was not a major pathway of the species' introduction into Eastern Europe, and it was contamination of imported forage (animal feed) and, to some extent, food (grain) that was responsible for the mass invasion of B. frondosa in the USSR.

In 1965, the USSR gave up the notorious corn campaign and started to import feed grain (first of all, maize) from the USA; further on, a vast amount of American feed grain had been imported since 1973 as a response to the decision to increase national food consumption and to maintain extensive livestock ( Mackie 1968, Novotny and Shull 1985, Allen 1987). This event coincides with the rapid rise of B. frondosa in the European part of the USSR ( Glazkova 2005), indicating that feed grain was the most likely source of the species' invasion. The coinciding increase in the abundance of B. frondosa in the 1970s-1980s was recorded in Belarus ( Dzhus 2020). Corn was dominating in the global production and export of feed grain ( Novotny and Shull 1985), and seeds of B. frondosa may be found harvested and transported together with that crop ( James et al. 2015).

Besides Eastern Europe, the second major area of the species' invasion in Russia is the Far East ( Morozova and Vinogradova 2018). The species arrived in that territory very early, being naturalised already by the beginning of the 1950s ( Vorobiev 1954). Its invasion has likely started from the port areas, where the species was widespread in the 1990s ( Barkalov 1992). Its active and continuous import with grain is therefore assumed.

The primary further dispersal of Bidens frondosa seed in urban habitats may occur with the aid of Fringillidae birds, domesticated animals or humans.

The common occurrence of Bidens frondosa along water streams suggests its further dispersal with water flows and transport. This type of dispersal was inferred for the first species' expansion in Central Europe ( Hejný and Lhotská 1964, Lhotská 1966).

The fruits of Bidens frondosa have two barbate awns, and their lateral margins are also barbate. This accounts for their ability to attach to the animal fur and feather, which, in the case of water birds, allows for successful dispersal of the species along aquatic habitats ( Carlquist 1966). This pathway was seemingly a major factor in the recent species' expansion in Eastern Europe ( Gudžinskas 1989, Glazkova 2005). The first occurrence of this kind was found at the estuary of the Dnestr River (Ukraine) already in 1968 ( Glazkova 2005).

Besides exozoochory, another proven way of the species' dispersal by aquatic birds is endozoochorous; various duck species are known to eat its seed, thus aiding their further dispersal ( Green et al. 2016). Water birds are apparently responsible for bringing the species to new localities, which are often hidden from even minor pathways of dispersal of weeds and ruderal plants (e.g. Leostrin et al. 2018).

Introduction to Kyrgyzstan

Period of introduction

Neophyte.

The first record of the species in Kyrgyzstan, dated 2008 ( Lazkov et al. 2011), most likely does not reflect its first arrival in the territory. Taking into account its first observation in Uzbekistan, dated 1990 ( Alexeev 1991), with its extensive naturalisation subsequently revealed in the beginning of the 2010s ( Maltsev 2013), the introduction should have started from the late Soviet period, during the 1980s, if not earlier.

Pathways of introduction

Transport - Contaminant: Contaminated bait. Transport - Contaminant: Seed contaminant. Transport - Contaminant: Contaminant on animals.

The most likely pathway of introduction of Bidens frondosa in Kyrgyzstan was its arrival with contaminated forage, but we also cannot exclude its appearance on corn fields as a seed contaminant. The occurrences along irrigation ditches may be zoochorous.

Further dispersal may occur with water, humans, domestic animals and water birds.

Invasion status

Naturalised.

Although most of the occurrences observed so far have been represented by just a few plants, and some were proven to have disappeared, the species is apparently on the way to its naturalisation in the country. It can be considered naturalised at least in the Botanical Garden in Bishkek.

No large populations or founder localities have been noticed so far.

Evidence of impact

Agriculture - minor impact (rarely occurring along irrigation ditches, once recorded as a garden weed). Native ecosystems - no impact (restricted to agricultural and urbanised areas). Urban areas - minor impact (rarely occurs in ruderal places).

Trend

Increasing (observed).

Figures

Figure 4. Currently recorded distribution of Bidens frondosa in Kyrgyzstan.

Figure 5. Bidens frondosa in Bishkek, Kyrgyzstan (photo by G. Lazkov, 19 June 2018).