A blogban az európai orchideákról, látonyafélékről és más érdekes növényekről, kutatásainkról, publikációkról, valamint a Debreceni Egyetem TTK Növénytani Tanszékén végzett munkáról, aktuális eseményekről, rendezvényekről, érdekességekről igyekszem hírt adni.
1.The red swamp crayfish (Procambarus clarkii), originally from North America, is one of the world's worst aquatic
invaders. It is a favoured prey item for waterbirds, but the influence of this
novel predator–prey relationship on dispersal of other organisms has not
previously been considered. We investigated the potential for dispersal of
plants and invertebrates by migratory waterbirds feeding on alien P. clarkii in European ricefields
at harvest time.
2.In November–December of 2014–2015, we
collected propagules from the outside of 13 crayfish captured as they moved out
of ricefields during harvest in Doñana, south-west Spain. We also collected excreta (N = 76 faeces, 14 pellets) of
lesser-black backed gull (Larus fuscus).
3.We recorded diaspores from at least
11 plant species (161 seeds from 10 angiosperm taxa, and 14 charophyte oogonia)
on the outside of crayfish, together with 54 eggs from eight aquatic
invertebrate taxa. Adults and juveniles of at least nine microcrustaceans,
including the alien ostracods Hemicypris
reticulata and Ankylocythere
sinuosa, were also recovered from crayfish. No intact propagules
were present in the digestive system of the crayfish.
4.Contents of regurgitated pellets
confirmed P. clarkii as the
main food item for gulls. Diaspores from at least 12 plant species (154 seeds
from 11 angiosperm taxa, and 17 charophyte oogonia) were recovered from gull
excreta, together with 129 eggs of 12 aquatic invertebrate taxa. A statoblast
of the alien bryozoan Plumatella
vaihiriae was found in gull faeces. Seven of the plant species are
important agricultural weeds, and two are alien to Spain. Diaspores from six plant
taxa were germinated, confirming viability. These propagules were from a
similar set of plants and invertebrates to those found on the outside of
crayfish, suggesting that propagules in gull excreta were ingested
inadvertently with their crayfish prey.
5.Ricefields constitute a major
artificial aquatic habitat covering an increasing proportion of the world's
land surface and typically support native or alien crayfish. Crayfish invasion
can lead to novel secondary dispersal pathways for plants and invertebrates
through interactions with their predators, promoting the expansion of alien and
native species (including weeds) through long-distance dispersal via migratory
waterbirds and increasing connectivity of organisms between artificial and
natural ecosystems. This represents a previously overlooked impact of crayfish
invasion on ecosystem services.
M.I., Molnár V. A., Valls L.,
Armengol X., Mesquita-Joanes F. & Green A.J. (2018): Crayfish invasion facilitates dispersal of plants and invertebrates by
gulls. –Freshwater Biology 63 doi 10.1111/fwb.13080