Journal of Mountain Ecology, 13 (2020): 41–50
The return of the Eurasian otter in
north- eastern Italy. New challenges for
biological conservation from Friuli Venezia
Luca Lapini, Renato Pontarini, Paolo Molinari, Giovanni Cantarutti,
Luca Dorigo, Stefano Pecorella, Nicola Cesco, Germano
Commessatti, Cristina Comuzzo, Juri Da Pieve, Elisa De Belli,
Angelo Leandro Dreon, Diego Giacomuzzi, Marco Luca, Alexandra
Mareschi, Gessica Picco and Anna Rossi
The Authors outline the present situation of the Eurasian otter Lutra lutra in Friuli Venezia
Giulia Region (north- eastern Italy). After about 50 years from its local extinction, the species
is surely coming back. The return probably dated back to 2006, but the ﬁrst proof was a
road kill on the Friulian Morainic Hills in 2011. Biomolecular data indicated an Austrian
origin of this ﬁrst specimen. Field researches did not conﬁrm this evidence until 2014,
when otter spraints were found near Fusine in Valromana (Tarvisio, Udine), close to the
Italian-Austrian border. Further ﬁeld work conﬁrmed that the whole Italian Danube
Catchment from Tarvisio Municipality is inhabited by a breeding nucleus of 4 to 7 otters.
Further bridge otter survey indicated that the distribution of the otters in the whole Friuli
Venezia Giulia Region was still increasing, both on the Carnic, Julian and Karavanke Alps,
up to the border with Veneto Region. The cohabitation with Neovison vison (Western
Carnic Alps) and the road mortality (8 road kills from 2011 to 2019) represent possible
threats to the establishment of a viable population in north- eastern Italy.
Keywords: Lutra lutra, distribution, north- eastern Italy, Friuli Venezia Giulia Region.
*Corresponding author: Luca Lapini
Published by the Gran Paradiso National Park.
OPEN ACCESS – Freely available on www.mountainecology.org
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42 Luca Lapini, Renato Pontarini, Paolo Molinari, et al.
Lutra lutra is strictly protected both in Italy (National Law 157/92) and in Europe
(Bern Convention and Habitat Directive EU 92/43 CEE). Being included in II and
IV Annexes of the Habitat Directive, the species requires constant monitoring and
six- yearly interval reporting to the EU. In Friuli Venezia Giulia monitoring is coor-
dinated by the public administration of the Autonomous Region Friuli Venezia
Giulia (Lapini et al., 2014).
The otter was historically quite common and widespread in northern Italy until
the middle of the 20th century, when it started to decline in many regions (Cassola,
1986). The species was relatively well distributed in large part of the Region Friuli
Venezia Giulia till the beginning of the 20th century, particularly in the wet
lowlands and hills of the Tagliamento River and Isonzo ﬂood plain (Figure 1)
(Lapini, 1985, 1986).
The extinction of the species in the Region probably dated back to 1967, when
the last specimen from the autochtonous reproductive population had been caught
on the Stella River, near Precenicco (Udine) (Lapini, 2012). The skull of this spec-
imen is still preserved in the Mammal Collection of Friulian Natural History
Museum (Lapini, 1988; De Marinis and Lapini, 1994).
In the subsequent years only sporadic records had been ascertained in the Region
(spraints in 1984 and 2008) (Lapini, 1985, 1986; Lapini and Bonesi, 2011), prob-
ably due to Austrian or Slovenian vagrant males.
In 2011 and 2012 two vagrant males were road killed in the same area of
Central Friuli Venezia Giulia Region (Municipality of Treppo Grande and
Trasaghis, Udine). The biomolecular investigations performed on the single
vagrant male road killed in 2011 in the Municipality of Treppo Grande (Udine:
Lapini and Bonesi, 2011) indicated strong afﬁnites with Austrian otters, thus
conﬁrming previous predictions of a possible expansion from Austria or Slovenia
(Lapini and Bonesi, 2011; Cianfrani et al., 2011; Loy et al., 2015)
The ﬁrst uncertain signs of its presence along the borders with Austria (Tarvisio
Municipality, Udine) dated back to 2006, when a single specimen entered in the
cooling pool of the snow chain Factory Weissenfels (today named Kito-Weissenfels
Chain Factory, Fusine in Valromana, Tarvisio, Udine). The animal was seen in
the pool and later running away from the pool by many factory- workers. This
sighting occurred along the mountain brook ‘Rio del Lago Inferiore di Fusine in
Valromana’. However, ﬁeld survey performed in July and in August of 2006 did
not allow to conﬁrm this interesting anecdotal datum (L. Lapini and L. Dorigo
Between 2013 and 2014, F. Iordan ran a survey of American mink (Neovison
vison) granted by University of Trieste (in the frame of the so- called Sharm Project).
During this survey otter spraints were found along the mountain brook ‘Rio del
Lago Inferiore di Fusine in Valromana’ (M. Pavanello obs., 18 March 2014:
Iordan, 2014). These were the ﬁrst conﬁrmations of otter presence in Danubian
waters from Italian Carnic and Karawanken Alps of Tarvisio Municipality (Lapini
et al., 2014; Pavanello et al., 2015) (Figure 2).
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The return of the Eurasian otter in north- eastern Italy 43
Figure 1 Otter- hunters from the Tagliamento River Catchment, Morainic Hills of Friuli
Venezia Giulia Region. Photo of the 1930–1940s of the 20th Century from Urbignacco Swamps,
Buja, Udine (Photo from archives Papinutto, Buja).
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44 Luca Lapini, Renato Pontarini, Paolo Molinari, et al.
In these zones the otter dwells in a 60-km drainage system of mountain brooks
tributaries of Danube trough the Rivers Slizza (in Austria via Gail and Drau) and
Sava Dolinka (in Slovenia), with a small reproductive population of at least 4–7
specimens (Lapini et al., 2014). This evidence stimulated additional extended
surveys, particularly aimed to check the status of the otter in the whole Friuli
Venezia Giulia Region.
Preliminary results are reported by Iordan (2014), Lapini et al. (2014), Pavanello
et al. (2015). First results were encouraging (Lapini, 2019), and ﬁeld work was
further implemented with the collaboration with ‘Progetto Lince Italia’ (Tarvisio,
Udine), the Carabinieri-Forestry Corps (Tarvisio Station); the Forestry Service of
the Region Friuli Venezia Giulia, and various volunteers.
This paper represents a provisional update of ﬁeld work results dated 23 June
We have chosen an extended bridge otter survey, ideally extended to all the 106
ETRS/LAEA Europe 10 × 10-km cells covering the whole Friuli Venezia Giulia
Region, including the Municipality of Sappada, only recently annected to Friuli
Venezia Giulia (Province of Udine) (National Law 182 of 15 December 2017).
Survey was performed at all available suitable bridges, which were systemati-
cally checked for otter spraints. A bridge was deﬁned suitable if characterized by
a structure able to stimulate the sprainting behaviour by otters (Pavanello et al.,
2015) and to preserve the otter spraints from rainfall (Figure 3).
Figure 2 The ﬁrst Eurasian otter Lutra lutra camera trapped in Friuli Venezia Giulia, near the
sprainting sites published by Iordan, 2014 (Piana di Fusine-Ratece, Tarvisio, Udine, 30 April
2014, Photo S. Pecorella).
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The return of the Eurasian otter in north- eastern Italy 45
Positive and negative sites were georeferenced and were reported on the ETRS
89 LAEA 10 × 10-km cartographic grid system. The overall data bank of this
survey will constitutes the base of further monitoring in the whole Region, in the
frame of the monitoring requested by the EU 92/43 Directive, partially granted by
the public Administration of the Autonomous Region Friuli Venezia Giulia (e.g.
Lapini et al., 2014).
PROVISIONAL RESULTS AND REMARKS
At present, we have surveyed only 38.68% (41 out of 106 10 × 10-km ETRS Cells)
of the whole Friuli Venezia Giulia Region, collecting various new records of otter
presence, both from sprainting sites and road kills or from other sure sources
(footprints, camera- trapping, alive recovered specimens, et so on) (Figure 4).
The presence of the otter is increasing on Julian and Carnic Alps, both to the
East (Tarvisio, Malborghetto Valbruna and Pontebba Municipalities) and to the
West (Forni Avoltri Municipality). An otter spraint collected on June, 15th, 2019
Figure 3 Physical characteristics of a bridge considered suitable for the present otter survey.
Bridge on the Geu-Acqualena brook (Forni Avoltri Municipality, Udine), 1025 m a.s.l., positive
for otter spraints on 15 June 2019. Foto L. Lapini/G. Cantarutti.
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46 Luca Lapini, Renato Pontarini, Paolo Molinari, et al.
Figure 4 Overall picture of the data about the Eurasian otter Lutra lutra in north- eastern Italy
(Friuli Venezia Giulia Region). Cartographic synthesis ETRS 89 LAEA 10 × 10 km. From Lapini,
1985, 1986, 1988; Lapini and Bonesi, 2011; Lapini, 2012; Iordan, 2014; Lapini et al., 2014;
Pavanello et al., 2015; Lapini, 2019; present survey (2014–2019). Neighbouring Slovenian terri-
tory has been only sporadically surveyed thanks to the cooperation with N. Krbis, G. Luznik and
Historic data before 1967 Uncertain data 1968–1983
Sure data (spraints and road kills) 1884–2013 Black circle: spraints, road kills, camera traps data
2014–2019; White circle: surveyed negative cells in
the same period
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The return of the Eurasian otter in north- eastern Italy 47
at the border between the Municipalities of Forni Avoltri (River Tagliamento
Catchment) and Sappada (R. Piave drainage system) suggests that the otter
could have also reached the Veneto Region, deserving further survey in this
We conﬁrmed the presence of the otter in the Municipality of Forni Avoltri. The
ﬁrst record of its occurrence in this area was dated 12 February 2017, when a
video made by S. Del Fabbro recorded a ﬁshing otter under the bridge of Forni
Avoltri village. The specimen, probably a 3–4 month- old cub, caught a big trout
under a boulder in the River watercourse.
In contrast, the lowlands of Friuli Venezia Giulia Region seem to be still avoided
The co- occurrence of the otter and the American mink was ascertained in the
Municipality of Forni Avoltri (Udine) (Iordan, 2014; Lapini, 2019), but at present
it doesn’t seems of particular concern. However, being an allochtonous invasive
predator (Bonesi and Palazon, 2007), the former should be eradicated from all
member states following recommendation by EU (Genovesi, 2000).
Road mortality surely represents the main threat for otters in north- eastern
Italy. During the period 2011–2019 at least eight otters were road killed in Friuli
Venezia Giulia Region (Table 1). Six were killed in the Municipality of Tarvisio,
one in the Municipality of Treppo Grande, and one in the Municipality of
Trasaghis (all in the Province of Udine).
Breeding seems to be quite frequent in the small otter population of Tarvisio,
with various newborns ascertained both by footprints, cub road kills, and puppies
rescued in the town of Tarvisio. Speciﬁcally, newborns have been ascertained in
2014 (footprints), 2015 (footprints), 2016 (footprints, camera trapping), 2017
(footprints, road kill of a three- month-old female cub, see Figure. 5), 2018 (foot-
prints, camera trapping) and 2019 (footprints, camera trapping, recovery of a
three- month-old live puppy in the centre of Tarvisio, this last recovered and
released on 24 May 2019).
To prevent road accidents in the Municipality of Tarvisio a speciﬁc EU Life
project has been planned aimed to mitigate otter road mortality.
We wish to thank U. Fattori and D. Colombi (Biodiversity Service of the
Autonomous Region Friuli Venezia Giulia) and D. De Martin and S. Costan
(Italian Carabinieri-Forestry Service from Tarvisio) for the constant cooperation
in the recovery of road kills from Tarvisio Municipality. A. Della Vedova and G.
Zufferli of the Regional Forestry Service (Wild Fauna Recovery Service) were also
always ready to cooperate with our group.
Many thanks also to M. Zanetti (ETPI-Service from ﬁsh community manage-
ment in Friuli Venezia Giulia), M. Colitti (Udine University) for their kind advices
in Public Awareness, and to G. Luznik, N. Krbis and B. Pellarini, which sent us
various information about the current Slovenian situation.
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48 Luca Lapini, Renato Pontarini, Paolo Molinari, et al.
Our preliminary ﬁeld bridge survey has been performed thanks to the Forestry
Service of the Autonomous Region Friuli Venezia Giulia, giving its support both
in the ﬁeld work and in various bureaucratic preliminary practices.
Special thanks to G. Muscio (Friulian Natural History Museum, Udine), A.
Altobelli and E. Pizzul (University of Trieste) for various practical advices. F.
Iordan and M. Pavanello also gathered important suggestions, particularly in the
years 2014 and 2015.
Table 1 Road kills of Lutra lutra from north- eastern Italy in the period 2011–2019 (Friuli
Venezia Giulia Region, Province of Udine).
Sex Locality Date Municipality Province Collector
Male Between the
Udine M. Lostuzzo obs.;
L. Lapini leg.
Male ? Highway bridge 10Aug2012 Trasaghis Udine L. Lapini and E.
Male Left bank of the
R. Slizza near
7Aug2016 Tarvisio Udine A. Chiavotti obs.;
M. De Bortoli, P.
Molinari and R.
Male Highway in loc.
21Aug2017 Tarvisio Udine P. Molinari leg.
Male Highway in loc.
9Sept2017 Tarvisio Udine P. Molinari leg.
Left bank of the
R. Slizza near the
sports ﬁeld of
28Nov2017 Tarvisio Udine F. Princi obs.; P.
Male? Highway near
13Apr2018 Tarvisio Udine P. Molinari leg.
Male Loc. Boscoverde,
15Mar2019 Tarvisio Udine R. Colloredo obs.;
R. Pontarini and
P. Molinari leg.
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The return of the Eurasian otter in north- eastern Italy 49
Figure 5 Above: right lateral vision of a two- three months old female cub road killed on 28
November 2017, in Tarvisio village (Udine). Photo D. De Martin.
Below: dentition of the same specimen, at the end of milk dentition. Photo L. Lapini.
36507.indb 49 26/02/2020 12:08
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