Transcript Slajd 1
Invasive species „But the cardoon (Cynara cardunculus) has a far wider range.: it now occurs in these latitudes on both sides of the Cordillera across the continent. I saw it in unfrequented spots in Chile, Entre Rios, and Banda oriental. In the latter country alone, very many (probably several hundred) square miles are covered with one mass of these prickly plants, and are impenetrable by man or beast. Over the undulating plains, where these great beds occur, nothing else can live. Before their introduction, however, I apprehend the surface supported as in other parts a rank herbage. I doubt whether any case is on record of an invasion of so grand scale of one plant over the aborigines” Charles Darwin 1839: Voyage of the Beagle. What are invasive species? Invasive species are those that • were accidently introduced into new habitats by man (alien species) • were intentionally introduced into new habitats by man for commercial purposes • were intentionally introduced into new habitats by man for biological control • greatly extended their natural home ranges towards new areas for instance due to climate change or human activities (roads, tunnels) Some well known examples Colorado Potato beetle First introduced to Europe in 1877 First record in Poland 1960 Gipsy moth First introduced into North America in 1868 Has about 650 different host plants During outbreaks causes major damages in softwood forests Tiger mosquito Nil perch The Asian species was first reported from Houston texas in 1985 Introduced into the great Est African lakes during the 1950s and 1960s to improve fishering. Now established in Brazil, Europe, and New Zealand Vectors of yellow and dengue fever, as well as encephalitis Changing cimate will promote the spread towards northern countries First occurrence in mainland France in 2006. Now recorded from Belgium, Italy, France, Balkan region. First deadly infection of Chikungunya feaver in Italy 2007. Caused dramatic changes in faunal and floral composition Caused algal blooms and eutrophication Caused the extinction of more than 200 native fish species (2/3 of all species) Eichhornia crassipes Introduced into China from South America in the 1930s as an ornamental plant, to provide liestock food and to control air pollution Caused reduction of lake areas and let to the extinction of about 30 fish species Reduced lake areas caused climate changes and changes in water cycling Marenzelleria viridis The flatworm was introduced via ship ballast water (first records 1979) In the vistula lagoon it has become the dominant species constituting up to 97% of the total biomass of the bottom- living macrofauna Harmonia axyridis In the USA unsuccessfully used as aphid predator in biological control programs since 1916. Sudden spread in USA since 1980. Major impact on natural communities of aphid predators due to its high reproduction rate. First observations of the Asian Lady beetle 2001: Belgium 2002: Germany, Netherlands 2004: UK, France 2007: Scandinavia, Poland 2009: Whole of Poland Unknown harvestman (Opilionida) species First observed in the Netherlands (2007) In 2008 massive invasion along the Rhine river up to Switzerland Species are up to 18 cm in diameter. They occur in large colonize of up to several hundred individuals. They show colonial movements. How many species are invasive? Number of native species Number of invasive species New Zealand (plants) 1790 1570 Hawaii (plants) 956 861 17591 4465 Tristan de Cunha (plants) 70 97 Campbell Islands (plants) 128 81 South Georgia (plants) 26 54 Southern Africa (freshwater fish) 176 52 California (freshwater fish) 83 52 Berlin (plants) 839 593 Woody perennials (Southern Australia) 2230 188 Europe (spiders) 3500 80 35 1700 Hawaii (all species) Great Britain (trees) Data from McNeely J. A. (1999), Kobelt and Nentwig (2008), Caley et al. 2008, and Sukopp (1990) How do alien species come to Hawaii? Miscellaneous Mails 2% 3% Baggage 40% Air cargo 39% Ship cargo 16% 25% of all Hawaiian species are alien A conceptual model of invading species Human activities Disturbance Changing land use Changing environmental conditions Habitat fragmentation Invading species Changing of ecosystem functioning Changing land management Increasing opportunities for invaders What makes a species invasive? Marcel Rejmanek (1946- Charcteristics of invasie species • r-strategists • have high dispersal ability • have small genome sizes • are habitat or feeding generalists • self pollinators (plants) • have long flowering periods (plants) • have a high proportion of leaf area (grasses) • have small seed sizes (in woody plants) • occupy often disturbed sites DNA contents of 148 Californian angiosperms (from Knight et al. 2005) What habitats are susceptible to invasions? • Early to mid-successional habitats • Mesic environments and open water • Disturbed habitats • Fragmented habitats Phylogenetic distance from the resident species „...floras gain by naturalization, proportionally with the number of native genera and species, far more in new genera than in new species” Charles Darwin 1959: The Evolution of Species by Means of Natural Selection Poaceae shared genera European genera Asteraceae shared genera European genera Brassicaceae shared genera European genera Number of European species NOT naturalized in California 466 257 681 762 230 342 Number of European species naturalized in California 43 69 22 66 12 36 2 <0.0001 <0.0001 <0.05 The analysis of plant species introduced to California shows that significantly more species of European genera were naturalized than of shared genera. (from Rejmanek 1999) Time lags Time lag (years) Trees Shrubs Time lag (years) Robinia pseudoaacia 152 Mahonia acuifolium 38 Acer negundo 183 Syringa vulgans 124 Prunus serotina 29 Symphoricarpus albus 65 Aesculus hippocastanum 124 Philadelphus coronarius 183 Quercus rubra 114 Lycium barbarum 70 Ailanthus altissima 122 Cornus stolonifera 76 Populus canadensis 165 Lonicera tatarica 94 Prunus mahaleb 54 Ribes aureum 61 Laburnum anagryroides 198 Colutea arborescens 265 Salix intermedia 112 Cornus alba 84 From introduction to spreading might pass a long time. Observed time lags from intyroduction to sprading in various trees and shrubs in the area of Berlin and Brandenburg (Kowarik 1995) Today’s reading Invasive species: http://en.wikipedia.org/wiki/Invasive_species Invasive species database: http://www.issg.org/database/welcome/ A different opinion: http://www.nytimes.com/2008/09/09/science/09inva.html