CONTENT - International Society of Zoological Sciences

S22 ICZ2008 - Abstracts
Mammal invasions in Europe: overview of patterns, trends,
impacts and possible responses
Piero Genovesi
Istituto Nazionale per la Fauna Selvatica, Ozzano Emilia (BO),
Italy
The recently completed DAISIE program, co-funded by the
European Commission within the 6 th Research Programme, has
implemented the most updated and comprehensive inventory on
alien species, storing data on over 10,000 alien species and
45,000 introduction events recorded in Europe.
As far as mammals are regarded, we recorded the presence of
around 88 alien species introduced in the different areas of Europe
after 1500, and of 397 events of introductions.
Alien mammals account for about 15% of the total mammal fauna
of Europe, and this proportion arises to over 20% if we only
consider terrestrial species. Mammal invasions are increasing at
very high speed, and the rate of new arrivals per year has passed
from 0.03 estimated before 1800, to 1 new specie per year
recorded in recent years.
An analysis of the pathways and vectors of mammal introduction
shows the increasing role of intentional import when compared to
accidental transport of species. In recent years several
introductions regarded pet species, confirming an increasing
importance of pet trade as a vector of invasions.
Among alien species, mammals are probably the most harmful
taxonomic group; introduced mammals cause in fact severe
impacts to biological diversity, are responsible for many extinctions,
but also significantly affect agriculture, forestry and other economic
activities. It is therefore urgent to improve our ability to prevent and
respond to mammal invasions. On the basis of the reviewed
information I provide some priorities to address the threats posed
by alien mammals in Europe.
Parasitism and biotic interactions: the cost of infection goes
beyond the individual level
Vincent Médoc, Jean-Claude Moreteau anf Jean-Nicolas Beisel
Laboratoire des Interactions Ecotoxicologie, Biodiversité,
Ecosystèmes (LIEBE), UMR CNRS 7146, Université Paul
Verlaine-Metz, 57070 Metz-Borny, France
Complex-life cycle parasites rely on the trophic pathway to reach
the successive hosts. These so-called “manipulator” parasites are
assumed to acquire the ability to modify various phenotypic traits
in their intermediate hosts to make them vulnerable to the
predation by definitive ones. Infection also affects how
manipulated preys perceive the wide range of predators out of the
parasite’s life cycle, expanding the cost of infection over the single
host/parasite association.
The freshwater amphipod Gammarus roeseli serves as an
intermediate host for the bird parasite Polymorphus minutus. We
investigated the cost of infection by P. minutus on the biotic
interactions that occur between G. roeseli and two non-hosts, the
invasive amphipod Dikerogammarus villosus, and the native
stickleback Gasterosteus aculeatus. Infected amphipods
interacting with D. villosus showed a prompt escape and then
sheltered close to the water surface whereas uninfected
individuals remained benthic. In water scented by sticklebacks,
both prey types showed an increased refuge usage, but the
response was exacerbated in infected preys. Consequently, in
microcosm experiments, infected G. roeseli became out of reach,
or at least less attractive, to the two predatory species, and thus
were less preyed upon than uninfected specimens suffering from
an increased predation pressure. From the parasite’s perspective,
the induced alterations could be of selective importance in
preventing the dead-end inside non-hosts of P. minutus. Beyond
host/parasite association, these results suggest that infection can
affect community dynamic through a shift in energy allocation,
modifying the availability of certain prey types according to their
infection status.
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Invertebrate invasions in Europe: patterns and trends
Alain Roques
INRA UR0633, Zoologie Forestière, Orléans, France
Within the framework of the European project DAISIE (Delivering
Alien Invasive Species Inventory in Europe), a first continental
inventory of the terrestrial invertebrate species alien to Europe has
been realized. This compilation revealed that 1501 exotic species
at least have right now established on the continent, and for the
majority they arrived accidentally. A significant acceleration of the
establishment process was observed since the 1990s, probably
due to globalization, During this period, the contribution of Asia
became gradually prevalent compared to North America. About a
half of the alien species have phytophagous habits and the trade
of ornamental plants, in all its forms (cut flowers, plants for planting,
seeds, bonsais,…) appeared to be the dominant pathway of arrival
in Europe. However, more than 60% of these species remained for
the moment confined to man-made habitats such as gardens and
parks, urban areas and cultivated fields whilst natural and seminatural
habitats such as forests remain little colonized. Whether
this situation reflects a lower resistance of man-made habitats to
invasion or the alien populations arriving in these habitats need an
accumulation phase before spreading in natural habitats remains
still unclear. Insects largely dominate the invertebrate species alien
to Europe, with a majority of Coleoptera and Homoptera. A
comparison of the relative representation of the orders and families
of insects among the entomofauna native and alien to Europe
indicated that Homoptera, especially aphids and scales, are
significantly more represented in the alien entomofauna; By
contrats, Hymenoptera and Diptera are uner-represented. More
generally, small-sized alien insects with sucking habits or
developing in concealed habitats (seeds) established much more
in Europe than large-sized external defoliators. These results
suggest to define at taxa level and/or guild level groups at risk for
future invasion. Other patterns possibly facilitating the introduction
and establishment such as prolonged diapause, polyphagy,
fecundity, … will be discussed during the conference.
Widespread distribution of the invasive Artemia franciscana
(Crustacea, Anostraca) in France: morphological, genetic and
morphometric data
Romain Scalone 1 , Mounia Amarouayache 2 and Nicolas Rabet 3
1 Institut fur Spezielle Botanik und Botanischer Garten Johannes
Gutenberg, Universitat Mainz Bentzelweg 9A 55099 Mainz.
Germany. ; 2 Laboratoire Bioressources Marines, Université Badji
Mokhtar, Annaba, Algeria; 3 UPMC, UMR 7138 CNRS UPMC
MNHN IRD, Case 05, 7 quai St Bernard, F-75005 Paris, France
New parthenogenetic and sexual populations of Artemia were
found along the French Atlantic and Mediterranean coasts. In
order to determine the specific status of these populations, we
used referential populations of A. franciscana (from USA) and A.
salina (from Algeria, Tunisia and Egypt). We present a genetic
study using the variability of the developmental caudal gene in
these populations (see Copf et al., 2003). In addition, a
morphological investigations of the frontal knob and penis of the
male specimens using the scanning electronic microscopy (SEM)
was conducted to support the molecular data. The usefulness of a
third morphological trait (the ratio of spine clusters on the frontal
knob) for the Artemia systematics is discussed in the light of a
statistical analysis using morphometric traits.
This study reveals that all French sexual populations of Artemia
belong to the species A. franciscana (Kellog, 1906) and not to A.
salina (Linnaeus, 1758) accepted as the sexual native species in
Mediterranean area. Recent publications on south of Europe and
North of Africa (Amat et al., 2005; Mura et al., 2006) are congruent
with our conclusions. The progressive replacement of the
parthenogenetic and endemic Artemia species by a sexual and
introduced species coming from North America, is fast and
recently seems to be accelerated. The new French Artemia
distribution is an additional example of an American invasive
species probably introduced by human and decreasing the
European biodiversity.