Predicting the spatial distribution of Ageratina adenophora in China
Ageratina adenophora (= Eupatorium adenophorum = E. cannabinum) (Asteraceae) was first discovered in the Yunnan Province of China around the 1940s. It is an herb invading riparian habitats, forest edges and disturbed areas. The well-documented invasion history of this plant provided the opportunity to examine the spatiotemporal patterns of its biological invasion. Datasets documenting 441 known localities invaded by A. adenophora in China over the past 50 years, and 23 environmental variables generated by the genetic algorithm for rule-set production model (GARP) have been used to test the predictability of A. adenophora distribution.
Maximum mean annual air temperature, precipitation in the coldest quarter and extreme low air temperature were considered to have the most influence on the prediction. Results indicated that A. adenophora may establish and spread out in Yungui Plateau, Sichuan Basin, South-Western Coastlands, Hainan Island and Taiwan, although is it currently absent or has only recently been recorded in these regions.
Ageratina adenophora’s populations in China tended to be more recent towards the Northern and Southern limits of their distribution range. In the initial phase of the invasion, the range was limited to several isolated locations centered on the Yunnan region. Subsequently, the weed continued to expand and established clusters of invasion foci. Over the last 60 years, this weed has spanned 23.4° of latitude and 9.6° of longitude. Over the past 20 years, A. adenophora has spread from subtropical areas with higher annual mean temperature and lower climatic fluctuations to much cooler and dryer areas at higher altitudes. The localities where A. adenophora was present were all in areas with mean annual air temperature ranging from 4.4°C to 23.1°C and annual precipitation from 698 mm to 2254 m. Within the regions of predicted presence, the majority of habitats had mean annual air temperatures ranging from 10 to 22°C and annual precipitations from 800 to 2000 mm.
In the EPPO region, this species is widely distributed. It is established in Albania, Algeria, Austria, Azerbaijan, Belarus, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Georgia, Germany, Hungary, Israel, Italy, Latvia, Lithuania, Moldova, Montenegro, Morocco, the Netherlands, Norway, Poland, Portugal, Romania, Russia, Serbia, Spain, Sweden, Switzerland and Turkey. It is therefore present in a very wide range of climatic conditions. It showed invasive behaviour in riparian habitats in Spain, but it is too widespread and there is not enough evidence of its negative impacts to be considered to be included in the EPPO lists.
Global Invasive Species Database – Eupatorium cannabinum. http://www.issg.org/database/species/ecology.asp?si=802;fr=1;sts=sss
Zhu L, Sun OJ, Sang W, Li Z, Ma K (2007) Predicting the spatial distribution of an invasive plant species (Eupatorium adenophorum) in China. Landscape Ecology 22(8), 1143-1154. http://www.springerlink.com/content/0663075744u9748h/