New records of exotic plants in Spain
The three following Poaceae have been found naturalized in the wild in Spain:
- Megathyrsus maximus var. vubiglumis (Poaceae, common name Guinea grass) (=;Urochloa maxima var. trichoglume = Panicum maximum var. pubiglume), a native of (sub)tropical Africa, was recorded in Spain in the provinces of Castellón and Valencia. This plant is a tall grass of about 2 m high, with a large branched panicle. The species is widely used in the tropics as a fodder plant and is therefore present in many countries (Australia, China, Ecuador, Indonesia, Japan, Malaysia, New Caledonia, Philippines, Puerto Rico, Republic of Korea, Taiwan, Thailand, United States, Vietnam, etc.). In Spain, the species is thought to have been planted for roadside vegetation and stabilization as it is present on a stretch of over 30 km along the road going from Torreblanca to Castelló de la Plana. This species seems to thrive in Spain and locally escapes. In its native area, this plant occurs from sea level to 1800 m. It can tolerate a wide range of habitats and colonizes agricultural areas, riparian zones and disturbed areas. This species has a strong allelopathic effect and reproduces profusely by seeds which are spread by wind, birds, flowing waters or as a contaminant of soil. It has been reported to suppress or displace local plants on fertile soils in pastures.
- Pennisetum clandestinum (Poaceae, common name Kikuyu grass) originates from Africa and is extensively cultivated as a forage or lawn grass in the sub-tropics. It is extensively sown in lawns in south-eastern Spain. Since 1992, P. clandestinum has been reported as established in mainland Spain, Islas Baleares and Greece. In Spain, it is reported as an escapee from cultivation in the provinces of Alicante and Valencia. In both areas, P. clandestinum forms dense, almost monospecific stands in or near riverbeds. As this species does not have conspicuous flowers, it might have been overlooked in other locations.
- Pennisetum setaceum (Poaceae) most probably originates in north-eastern Africa and Arabia, and is grown as an ornamental in the arid areas of southern Europe. The species is reported as established in Italy (including Sardinia), Spain (including Islas Canarias, and Islas Baleares). In Spain, the species has escaped in the wild in the provinces of Alicante, Granada, Malaga and Valencia. P. setaceum is considered one of the most aggressive alien invaders in Islas Canarias, especially in the coastal area. Its management there has proven very expensive and time-consuming. Since climatological and environmental conditions are rather similar in Islas Canarias and the south of Spain, P. setaceum is very likely to become invasive in mainland Spain as well.
Considering the invasive potential of these three alien species, a monitoring programme should be carried out to better understand their geographical distribution and impact.
Sources
Delivering Invasive Alien Species Inventories for Europe (DAISIE) Database. http://www.europe-aliens.org/
Global Invasive Species Database – Pennisetum clandestinum. http://www.invasivespecies.net/database/species/ecology.asp?si=183;fr=1;sts=sss;lang=EN
Global Invasive Species Database – Pennisetum setaceum. http://www.invasivespecies.net/database/species/ecology.asp?si=309;fr=1;sts=sss;lang=EN
Global Invasive Species Database – Urochloa maxima. http://www.invasivespecies.net/database/species/ecology.asp?si=398;fr=1;sts=;lang=EN
Verloove F (2006) Exotic grasses running wild: Megathyrsus maximus var. pubiglumis (Poaceae, Paniceae) – new to Spain. Bouteloua 1, 55-60.