Plant invasions in Hungary

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Plant invasions in Hungary

• Zoltán Botta-Dukát
• Institute of Ecology and Botany
• Hungarian Academy of Sciences

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Outline of the lecture

• Basic terms
• Main habitats, their invasibility and their
  invasive species
• What kind of plants invasive in Hungary?
• Recent survey project

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Basic terms I.

• native species species that survive the Ice Age
  in the studied area or established after the Ice
  Age without any human activity
• alien (non-native) species species that appeared
  in the studied area due to (intentional or
  unintentional) human activity. In the case of all
  species that appeared after the neolith, we
  suppose the human activity. Hybrids of aliens
  are also alien species, even if they are evolved
  in the studied area (e.g. Fallopia x bohemica)

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Basic terms II.

• established species subgroup of aliens alien
  species that can survive without human activity
• invasive species subgroup of established
  species species that spread in considerable
  speed (or finished the spreading, because
  occupied all available habitat)

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Basic terms III.

• when we classify a species into the group of
  invasive species, we must not consider its effect
  the natural vegetation
• environmental weed (often, but not always
  invasive) plants that take considerable negative
  effect to the natural vegetation.
• transformer invasive species that can change the
  structure, composition or function of natural
  communities

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Main habitats

• Submersed vegetation
• Floodplains and other wet habitats
• Sandy grasslands
• Rock grasslands
• Other dry grasslands
• Alkaline vegetation
• Semi-natural forests
• Forest plantations (Robinia and Populus
  plantations)
• Ruderal areas and arable fields

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Submersed vegetation

• low invasibility
• in the end of 19th century and in the first part
  of 20th century Elodea canadensis was the main
  invasive plant, recently its population size
  decreases
• in thermal waters tropic plants (e.g. Cabomba
  caroliniana, Gymnocoronis spilanthoides)
  establish and spread

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Elodea canadensis
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Cabomba caroliniana
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Gymnocoronis spilanthoides
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Floodplains and other wet habitats

• the highest invasibility
• many different invasive species
• aliens often form monodominant stands
• invasion endangers the native flora and
  vegetation
• most successful life forms tall-herb perennials,
  trees, lianas, shrubs

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Aster spp.
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Fallopia spp. (Fallopia x bohemica)
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Helianthus tuberosus agg.
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Solidago gigantea
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Rudbeckia laciniata
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Impatiens glandulifera
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Xanthium italicum
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Why are tall herbs such successful?

• The observed pattern
• other groups of invasive plants do not change the
  life form spectra (e.g. invasive trees replace
  the native trees)
• tall herbs can occupy empty niches and can
  over-compete native species with other life forms
  (e.g. grasses)
• Supposed explanation
• Hungarian flora unsaturated in the point of this
  group

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Acer negundo
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Fraxinus pennsylvanica
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Amorpha fruticosa
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Echinocystis lobata
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Vitis riparia
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Parthenocissus inserta
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Sand grassland

• high invasibility
• most of the invasive species are annual, they do
  not change the structure of vegetation (the
  species richness and cover of native annual are
  high in this vegetation type)
• invasive perennials and trees destroy the native
  vegetation

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Conyza canadensis
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Ambrosia artemisiifolia
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Cenchrus incertus
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Asclepias syriaca
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Robinia pseudoacacia
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Ailanthus altissima
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Rock grasslands

• low invasibility
• Pinus nigra were planted by foresters and in some
  places (mainly in dolomite) it spreads

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Pinus nigra
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Semi-natural forests

• moderate invasibility
• some planted alien tree established and became
  invasive
• invasive species are rare in the herb layer

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Prunus serotina
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Celtis occidentalis
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Ailanthus altissima
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Impatiens parviflora
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Forest plantations

• high invasibility
• very low biodiversity, in the herb layer often
  only invasive plants occur

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Asclepias syriaca
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Phytolacca americana
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Ribes aureum
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Solidago gigantea
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Solidago canadensis
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Ruderal areas and arable fields

• high invasibility
• mainly thermophilous annuals

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Amaranthus spp.
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Ambrosia artemisiifolia
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Conyza canadensis
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Eleagnus angustifolia
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Eleusine indica
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Erigeron annuus agg.
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Galinsoga quadriradiata
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Heracleum mantegazzianum
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Oxybaphus nictagineus
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Senecio inequidens
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Solidago gigantea
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What kind of plants are invasive in Hungary?

• two groups of alien species were compared
• established but non-invasive in semi-natural
  habitats
• invasive in semi-natural habitats

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• Among the invasive species there are
• more species able to vegetative reproduction,
• less species spread by endozoochory,
• more species with North American, but less with
  Mediterranean origin,
• more species belong to Asteraceae,
• more geophytes and less biennial
• than in the non-invasive group.

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Invasive species

• prefer nutrient rich environment
• tolerate shade more than non-invasive established
  species

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Recent survey project

• in the framework of Hungarian Flora and
  Vegetation Mapping Project (supported by the
  Hungarian Government, done by more than 200
  botanists)
• the project started in September 2002, and it
  will finish August 2005
• units of data collection ca. 6x5 km squares and
  ca. 35 ha hexagons

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Data collected in 6x5 km quadrats

• presence of invasive species
• abundance (in 3-level scale) and habitat
  preference of the 25 most important alien species
  (the data collector can add new species to the
  list)
• in each habitat the strength of effect of the 10
  most important invasive species (the data
  collector can add new species to the list)

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Data collected in 35 ha hexagons

• cover of alien species (arable fields are
  excluded, because the cover of aliens change
  dramatically within year there)
• in each habitat it is endangered by invasion or
  not

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Literature

• Balogh L., Botta-Dukát Z., Dancza I. 2003. What
  kind of plants invasive in Hungary? In Child,
  L.E. et al. Plant Invasions Ecological Threats
  and Management Solutions. pp. 131-146, Backhuys
  Publishers, Leiden, The Netherlands
• Török K., Botta-Dukát Z., Dancza I., Németh I.,
  Kiss, J., Mihály B., Magyar D. 2003. Invasion
  Gateways and Corridors in the Carpathian Basin
  biological invasions in Hungary. Biological
  Invasions, in press
• Toth Cs., Botta-Dukát Z.in prep. Effect of
  invasion to the guild structure of riparian
  communities in the Carpathian Basin

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Thank you

• to my co-authors,
• to colleagues, whose photos were downloaded from
  the Internet and used in this presentation
• to Milan Chytry, for the invitation to give this
  lecture

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Thank you for your attention!