(Hydrachnidia) from springs in Trentino
1.000 species are presently recorded from Europe. About one third
of them is found regularly in springs and about 20 % are strictly
bound to this habitat-type ("crenobionts"): such species
are unable to complete their life cycles e in streams, in groundwater,
or in stagnant waters.
Notwithstanding intense research, detection of species new to science
is possible also in the better studied parts of Europe. In the course
of the CRENODAT project, the presence of 45 species has been documented
so far in springs of the Trentino. Also here we discovered a species
never registrated before.
Obviously, the population of the genus Lebert a, characterized by
striking morphological features, is phylogenetically far distant
from all known representatives of the genus: The stout mouth parts
are flanked by a strange, nose-shaped extension of the anterior
coxae; of particular interest is the presence of six pairs of osmoregulatory
"acetabula" in the genital field.
As is evidenced by SEM photographs, the increased number of these
organs is reached by bipartition of the typically three pairs of
"acetabula" found in other species of the genus. So far,
this character state was known only in members of the family Torrenticolidae.
In the newly discovered species the doubling of acetabula was surely
reached by parallel evolution, phylogenetical relations between
the two clades are to be excluded. The new species obviously represents
also a subgenus new to science and will be described soon in a scientific
Larvae di Chironomidi (Orthocladiinae e Diamesinae)
Chironomid larvae of Orthocladiinae and Diamesinae
Capsula cefalica larvale di Diplocladius cultriger (sorgente
Larval head capsule of Diplocladius cultriger (spring
Chironomids are the most abundant components of the spring
macrobenthic fauna. These opportunistic insects inhabit a great
variety of aquatic habitats, from lentic to lotic ones, thanks
to their ability to tolerate wide chemico-physical gradients.
Therefore they can colonize almost every kind of ecological
niches in freshwater ecosystems. Some taxa developed special
physiological, morphological and behavioural adaptations to
survive extreme conditions, like freezing and droughts.
Thanks to their ubiquity and species richness (about 15000 species
recorded all over the world and more than 400 in Italy), Chironomids
are considered good bioindicators for habitat assessment. At
present, about 70 species are recorded from Alpine springs,
mainly belonging to Orthocladiinae and Diamesinae subfamily.
Many are rheophilic and cold stenothermal organisms, adapted
to live in mountain streams and reocrene springs. Some species
are rare and stenoecius, such as Diplocladius cultriger Kieffer
1908, an orthoclad found in the spring Antermont Bassa during
the CRENODAT survey: this is the first record of this taxon
in the Italian Alps.
and vascular plants in Trentino’s springs: preliminary results
By now the botanical working group, coordinated by Marcello
Tomaselli from the Parma University, performed a lot of vegetation
relevés (about 85 in 2005 and 50 in 2006). More than
120 species of bryophytes and about 90 of vascular plants have
been till now identified. Among bryophytes the most widespread
are several species belonging to the genera Palustriella, Plagiomnium,
Rhizomnium and Philonotis. The list of most common species includes
also Brachythecium rivulare, Bryum pseudotriquetrum, Cratoneuron
filicinum and Scapania undulata. A specimen very close to Palustriella
falcata was collected in the springs Rislà and Antermont:
the collected samples have a pluristratose lamina like to that
of Palustriella pluristratosa, a species recorded and described
for the first time in Switzerland. Presently, Prof J.P. Frahm
(University of Bonn) is performing a molecular analysis on this
interesting specimen. Among vascular plants Cardamine amara,
Saxifraga stellaris, S. rotundifolia, and Crepis palustris are
the most commons species. Also different species of the genus
Epilobium are very frequent.
Besides this mainstream of the work we’re performing
two field experiments: the first one deals with the growth rate
of Palustriella commutata artificially exposed to three different
treatments: submersion, sub-emersion and emersion. The second
one aims at investigating the relationships between the water
content of several species and their pigments investigated by
means of spectrophotometer.
Springs are an interesting ecotone to be studied and represent
a hard challenge for zoologists. Among the several taxa which
can be found living in a spring (dipteran, copepods, molluscs,
mites, diatoms etc...) nematodes (Fig.1) play an important ecological
role. Their diversity is high. At the moment more than 70 species
of nematodes had been found in springs sampled within the Crenodat
project. Nematodes we found are distributed all along the entire
trophic web since they can be bacteriovorous (Tobrilidae, Plectidae)
(Fig. 2 –3), herbivorous (Dorylamidae) (Fig. 4) and predators
(Monochidae). They can be used to assess environmental condition
through the application of indexes such as the Maturity Index
based on their reproductive strategy.
Springs has never been deeply studied and it is easy to find
new species adapted to this habitat. During the identification
of nematodes sampled in the Crenodat project we found a new
species of Eumonhytera.
In a couple of spring two nematodes belonging to species Tobrilus
zakopanensis (Stefanski, 1924) and Eumonhystera tatrica (Daday,
1896): at the moment these two species were known only from
a mountain region on the border of Poland and Slovakia (Tatry).
The presence in these spring suggests the hypothesis of a biogeographical
relict left behind since last glaciation.
pic 1: Habitus of Plectus parietinus.
Epitobrilus allophysis (Stephansky, 1924), bacterial feeder.
The arrows indicate the mouth cavity and a tooth beneath it.
Pic2: The connession between pharynx and the intestine.
pic3: The arrow indicates the odontostyle.
Oligochaetes (Beatrice Sambugar)
Three aquatic Oligochaete families are found in spring environments:
Tubificidae, Lumbriculidae and Haplotaxidae. Some Lumbricidae
can also be found, e.g. Eiseniella tetraedra, and Enchytraeidae,
which include terrestrial and aquatic species and have been
found to be very common in underground aquatic (Giani et al.,
2001) and ecotonal environments, such as springs (Sambugar et
In this last study, the fauna examination of several European
springs highlighted the important role, also in these environments,
of Oligochaetes, one of the most abundant and diversified groups
of invertebrates, following the Diptera Chironomidae. Over 70
species have been identified; the coenoses appear to be made
up by a great nucleus of ubiquitous species and by rare crenobitic
and stygobitic species. Enchytraeidae and Tubificidae are the
most abundant and species-rich families.
The importance of springs as ecotones between underground and
surface environments is underlined by the compositions of communities
made up by genera, e.g. Pristina, which are very frequent in
underground waters, other genera, e.g. Rhyacodrilus, Buchholzia
and Trichodrilus, which are often present in cave stygofauna,
and yet other genera, e.g. Cognettia, which are common in soils
and superficial water courses. Two environmental variables that
mostly affect the Oligochaetes coenosis composition are the
substrate and the geology of the spring area.
OLIGOCHAETES OF SPRINGS IN TRENTINO
Enchytraeidae are the most diversified family in the springs
of Trentino, followed by Tubificidae, Lumbriculidae and Haplotaxidae.
About one third of Enchytraeidae is represented by Cernosvitoviella,
the sole genus with only aquatic species. Cognettia cognettii,
C. cfr. glandulosa and Fridericia discifera, which were found
in some springs, are indicated for the first time for Italian
spring environments. Cognettia sphagnetorum and Mesenchytraeus
armatus, both holarctic and amphibious species, had already
been signaled for spring environments: the former for a spring
in France and for a spring in Italy, the latter for several
Italian springs (Sambugar et al., 2005). Enchytraeus, Fridericia,
Henlea, Marionina and Cernosvitoviella are found genera and
were already known for surface and underground waters.
The Tubificidae Nais alpina, N. communis, N. variabilis, N.
simplex and Tubifex tubifex are cosmopolitan and ubiquitous,
having already been found in spring environments. The presence
of T. tubifex in helocrene springs underlines its choice of
environments with a high content of organic detritus.
The tubificid Pristina bilobata, the lumbriculid Stylodrilus
heringianus and the haplotaxid Haplotaxis gordioides are stygophyles
and corroborate the ecotonal characteristics of spring environments
since these are points of contact between underground and surface
habitats. H. gordioides is signaled for ther first time for
Italian spring environments.
The studies on Italian springs carried out to date confirm,
even as regards oligochaete populations, the peculiarity and
complexity of such environments, points of high biodiversity
that must be protected and preserved.
Giani N., Sambugar B., Rodrìguez P., Martìnez-Ansemil
E., 2001. Oligochaetes in southern European groundwater: new
records and an overview. Hydrobiologia, 463: 65-74.
Sambugar B., Martìnez-Ansemil E., Giani N., 2005. Oligochaetes
from springs in southern Europe. Bollettino del Museo Civico
di Storia Naturale di Verona, 29, Botanica Zoologia: 93-106.
Altogether, 100 samples collected on different substrata from
64 alpine springs were analysed. In 9 samples no ostracods were
found, in 6 samples only immature stages were present, while
other 6 samples contained only empty valves. Both soft parts
(dissected in glycerine and stored in sealed slides) and valves
(stored dry in micropaleontological slides and used for scanning
microphotographs) were checked for species identification, using
CRENODAT – Freshwater
Juri Nascimbene - University of Trieste, Biology Department,
via Giorgieri 10 – 34100 Trieste
Lichens mostly colonise terrestrial habitats. However, a few
species are restricted to submerged or partially inundated habitats.
Freshwater lichens are widespread thorough Europe as typical
elements of vegetation of springs, rivers, and lakes. Freshwater
lichens belong to a few genera the most representative being
Verrucaria. Species distribution is affected by several ecological
parameters such as inundation, substrate and water pH, substrate
stability, light, silting, and eutrophycation. Since they are
sensitive to habitat modifications and threatened by water pollution,
they could be used in freshwater biomonitoring. For their conservation
a generalized habitat protection is a prudent approach that
can compensate for poor taxonomic knowledge, especially in protected
areas. Particular care should be devoted to springs, due to
their structural vulnerability. Springs are considered the optimal
habitat for several species of Verrucaria.
Forty-three freshwater lichens are known from the Italian Alps.
The species belong to 20 genera, the most species-rich being
Verrucaria (19% of the total), Aspicilia (10%), Dermatocarpon
(10%) and Staurothele (10%). Crustose lichens with sexual reproduction
comprise 80% of the total. The photobiont is mostly a coccoid
green alga (72%), while cyanobacteria and trentepohlioid algae
are less frequent (21% and 7%, respectively). The altitudinal
distribution of freshwater lichen richness has a maximum in
the subalpine belt near the treeline (93% of the total), followed
by the montane belt (77%), the alpine belt (63%) and the submediterranean
belt (9% only). The subalpine belt also hosts the highest share
of those species restricted to the Alps in Italy (91%), followed
by the alpine belt (78%) and the montane belt (60%). Most species
(80%) colonise acid or subacid rocks and have an ecological
optimum in well-lit habitats.
Among aquatic Verrucaria species found during CRENODAT project,
Verrucaria funckii can be considered the most representative,
since it is rather frequent in several springs on perennially
inundated siliceous substrates, in different altitudinal belts.
The material collected was submitted both to morphological and
molecular analysis for a correct identification. Verrucaria
funkii belongs to a rather critic group including V. hydrela
and V. elaeomelaena, both found in the spring of Trentino, mostly
on siliceous and calcareous rocks respectively. This group is
characterized by a gelatinous green, olive-green, brownish thallus
in which the algae are often typically arranged in columns.
Spores length normally ranges between 20-25µ.
Verrucaria sp. with a greenish gelatinous thallus in Val Borzago
(Adamello Natural Park)
Verrucaria sp., thin section of the thallus and a of a fruiting
body containing the spores. The gelatinous thallus covers the
fruiting body. Algae are arranged in columns.
Verrucaria margacea grows mainly on siliceous rocks in perennialy/periodically
inundated habitats. It normally has a dark coloured thallus
and it is characterized by large spores (at least 25µ
mites (Hydrachnidia) from springs in Trentino
studies have produced evidence that water mites play an
outstanding role within invertebrate communities of spring
habitats, not only in terms of species diversity and the
evolution of particular habitat preferences, but often also
with regard to their high population densities and particular
significance within the food web.
At the nymphal (more correctly: deutonymphal) and adult
stage they are predators of minute invertebrates or invertebrate
eggs, while larvae of most species have a parasitic-phoretic
life style and are bound to particular insect hosts. The
complex life cycle is completed by two pupa-like resting
stages (protonymph, between larva and deutonymph, and tritonymph,
between deutonymph and adult), which need protection in
microcavities of the sediment under stable environmental
conditions. Due to requirements of single stages, water
mites are particularly interrelated with the biotic and
abiotic components of their environment.
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