The Alien Flora of Greece: Taxonomy, Life Traits and Habitat Preferences
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Biol Invasions DOI 10.1007/s10530-010-9749-0 ORIGINAL PAPER The alien flora of Greece: taxonomy, life traits and habitat preferences Margarita Arianoutsou • Ioannis Bazos • Pinelopi Delipetrou • Yannis Kokkoris Received: 13 May 2009 / Accepted: 29 March 2010 Ó Springer Science+Business Media B.V. 2010 Abstract The aim of the paper is the state-of-the-art the native flora. Regarding flowering traits, most of assessment of the alien flora of Greece and its traits. the aliens have a long flowering period (over The dataset consists of a total of 343 alien taxa, 1 month) and flower in late spring, summer and including 49 archaeophytes. The taxonomy, life traits autumn, when few of the native plants are in bloom. and habitat of the 294 neophytes are analysed vs their Vertebrate zoochory and anemochory are the two naturalisation status. Out of the 122 (41%) natura- dispersal modes mostly utilised by the alien plants lised neophytes, 50 are identified as exhibiting (43 and 28%, respectively), while more than one invasive behaviour. Poaceae, Asteraceae, Amaranth- dispersal mechanisms are functional for 56% of them. aceae, Solanaceae, Fabaceae, and Polygonaceae are Artificial habitats have the highest frequencies of the plant families richest in alien taxa. The majority alien plants. The natural habitats with the highest of them are of American origin, followed by those of numbers of aliens are the coastal ones and inland Asiatic and Mediterranean origin. The neophytes are surface waters. Opuntia ficus-barbarica, Ailanthus predominantly herbs, most of them annuals. Yet, the altissima, Oxalis pes-caprae, Erigeron bonariensis, perennial life cycle is equally frequent with the Amaranthus albus and Symphyotrichum squamatum annual one and the proportion of phanerophytes in are typical cases of plants characterised as invasive, the alien flora is increased compared to the one of having established in almost all the habitat groups identified. The diversity of the ecological character- istics of the plants suggests a potential of impacts that needs to be further assessed. & M. Arianoutsou ( ) Á Y. Kokkoris Keywords Plant invasions Á Species traits Á Department of Ecology and Systematics, Faculty of Biology, School of Sciences, Habitats Á Mediterranean basin University of Athens, 15784 Athens, Greece e-mail: [email protected] Introduction I. Bazos Botanical Garden, Department of Ecology and Systematics, Faculty of Biology, School of Sciences, Although the phenomenon of biological invasions has University of Athens, 15784 Athens, Greece been noted for some time (Elton 1958), it is only during the last two decades that the biological P. Delipetrou Department of Botany, Faculty of Biology, School of consequences of exotic invasions have been Sciences, University of Athens, 15784 Athens, Greece researched extensively. This is due to the realisation 123 M. Arianoutsou et al. of the significant losses of the biological diversity and Aegean Islands, e.g. Lesvos (Bazos 2005), Chios function of the ecosystems invaded and the economic (Snogerup et al. 2001), Kalymnos (Zervou and impacts caused (Mooney and Hobbs 2000; Mack Yannitsaros 2009). However, there had been no et al. 2000; Vila` et al. 2009). Vascular plants are checklist of the alien taxa of Greece. The current among the most ubiquitous invasive organisms. The paper is based on the data inventory carried out under majority of the plants have been introduced for the DAISIE project (http://www.europe-aliens.org/), agricultural, silvicultural, ornamental or medicinal which was complemented by information on plant purposes (Williamson 1996), while many have been traits and habitats. It provides for the first time a accidental introductions (Newsome and Noble 1986). complete catalogue of the alien plants of Greece Two basic questions have fascinated ecologists based on up-to-date information, and it aims to since biological invasions have become a focal issue address basic but essential questions such as the of the global change (Pysˇek and Richardson 2006). number and naturalisation status of the neophytes, The first question articulated was ‘‘which species their taxonomic identity and origin, and their bio- invade and under which conditions?’’ This question logical and ecological profile. has stimulated the search for traits that make plant species potential successful invaders (e.g. Lloret et al. 2004; Pysˇek et al. 1995, 2009). The second question Methods was ‘‘what features of ecosystems make them either prone or resistant to invasions?’’ This has lead to Area of study studies on community characteristics and environ- mental conditions under which an invasive event is Greece occupies the southernmost part of the Balkan realised (e.g. Davis et al. 2000; Vila` et al. 2007). It is Peninsula and has a total land territory of approx. only recently that these two questions have been 132,000 km2. By land it is bordered by Albania, considered in concert (Richardson and Pysˇek 2006; Former Yugoslav Republic of Macedonia and Bul- Weber et al. 2008). garia from the north, and the European part of Turkey Despite the fact that there are several independent from the northeast. The continental mainland is research efforts in the field of invasion ecology in surrounded by the Aegean Sea to the east, the Libyan Europe, it is only recently that a systematic and Sea to the south, and the Ionian Sea to the west. The synthetic approach has been adopted on investiga- insular part occupies more than one-fifth of its total tions into alien species in Europe (DAISIE 2009). area and includes more than 2000 islands (only 227 Prior to the DAISIE work only few European of which are inhabited) (Strid and Tan 1997). countries had sound information on the composition Although a small country, Greece, owing to its of their alien floras, available in specialised check- geomorphology and dissected landscape, has an lists, namely Austria (Essl and Rabitsch 2002), the extremely wide range of natural habitats ranging Czech Republic (Pysˇek et al. 2002), Germany (Klotz from alpine to almost xeric. Eighty percent of Greece et al. 2002;Ku¨hn and Klotz 2003), Ireland (Reynolds consists of mountains or hills which make it the third 2002), the United Kingdom (Clement and Foster most mountainous country in Europe (Dax and 1994; Preston et al. 2002, 2004) and recently Italy Hovorka 2005). The mountains, many of which (Celesti-Grapow et al. 2009). exceed 2,000 m in height, provide a wide range of The study of the alien vascular flora of Greece habitats, including a large variety of shrublands, started in the early 1970’s (Yannitsaros 1982). It forests, and meadows. The lowlands include lakes, became more intense and systematic during the last streams, river deltas and lagoons of international two decades and many new records were added. importance. In terms of ecosystem types Greece Some of the Greek regions for which there is possesses a great diversity, as a result of the complex sufficient knowledge of the alien flora are Attica relief and the relatively mild, until recently, human (Yannitsaros 1982), the island of Crete (Yannitsaros activities. The most extended ecosystems are the 1991; Turland et al. 1995), the urban areas of Mediterranean maquis, phrygana and forests covering Thessaloniki (Krigas and Kokkini 2004) and Patras 40% of the area (Arianoutsou and Diamantopoulos (Chronopoulos and Christodoulakis 2000) and some 1985). Greece has the tenth longest coastline in the 123 The alien flora of Greece World (15,000 km total, 7,300 continental and 7,700 intensification and shift of economic activities to in the islands), hence coastal, marine and island the secondary and tertiary sector has increased habitats comprise a priority for the country (Strid and environmental problems and threats to Greece’s Tan 1997). natural environment. The most serious human Greece, being part of the Mediterranean Basin was impacts are wetland reclamation, desertification due settled by humans very early. As a consequence to repeated fires, frequently coupled with grazing, Mediterranean landscapes have long ago experienced development of coastal housing and tourism infra- the human impact. Indigenous agriculture and animal structure. Increased emissions of various kinds of husbandry have been practiced here for more than pollutants and pollution of air, water, and soil have 10,000 years (Naveh 1998) in combination with also been recognised as significant problems. deforestation practices and fire management. Plant community structure and diversity patterns have Data sources-database therefore evolved under the influence of this interac- tion, as is also the case for the other Mediterranean The dataset analysed here originates from the data- type regions of the world (Cowling et al. 1996). base ‘‘Alien’’, an upgraded version of the one These patterns were kept at a dynamic equilibrium at compiled for the DAISIE project (Pysˇek et al. 2009; least until the Second World War (Caravello and http://www.europe-aliens.org/), complemented with Giacomin 1993). Since 1950, major changes have additional and updated information. The database occurred to the economies, the livelihood and hence includes tables with multiple records for the status, the landscapes of the country. Initially, there were distribution, introduction and ecological traits of each extensive rural migrations followed by agricultural plant. The data recorded were based on the investi- intensification from the introduction of new farm gation of 283 sources of which 234 were used for the machinery, new strains of cereals and tree crops and plants of ‘‘Appendix IV’’. The sources (‘‘Appendices extensive application of fertilisers. The invention of I and II’’) include mainly original articles and stan- new irrigation techniques made the use of hilly areas dard floras and checklists such as Flora Hellenica possible, so agriculture spread further. Land aban- (Strid and Tan 1997, 2002), Flora Europaea (Tutin donment, tourism development, population concen- et al. 1968–1980, 1993) and Med-Checklist (Greuter tration along the coast, and the building of extended et al. 1984–1989; Greuter and von Raab-Straube transportation networks characterized the last two 2008).