The Park » Projects » The Reintroduction of the Marmot

The re-introduction project

Motivations

The project of re-introducing the marmot in the Dolomiti Bellunesi National Park is based first of all on the great vocation of its territory. The study of feasibility which preceded the re-introduction in fact individuated a fauna capacity of about a thousand marmots. The main reasons for re-introducing the species are ecological:

• Conservationist motivations - The reintroduction allows contributing significantly to the conservation of the species, and expanding its distributional area in the southern part of the eastern Alpine arc.

• Fauna and ecosystem motivations - The project allows increasing the completeness and diversity of the Park's zoocoenosis, improving the balance between the various fauna components. The marmot is, in fact, a primary consumer typical of high altitude Alpine prairies, and whose role in utilizing the fixed energy of the high altitude vegetation and in making it "give fruit" through the trophic web of the Alpine ecosystem is of primary importance. The presence of good populations of marmots positively affects the populations of other species, in a direct or indirect way. In a direct way in the sense that it implies an increase in the quality of the Park's habitat for the golden eagle (Borgo & Mattedi, 2003b) and for the lynx. In an indirect way in that the availability of marmots should allow a decrease in the quantity of the summer predation of taxonomic groups with a higher conservationist importance, such as Galliformes and Lagomorphae.

Besides these ecological motivations, there are others of socio-economic and cultural nature. Thanks to its aspect and visibility, the marmot is, in fact, a species with a great impact on the public, and which therefore lends itself more than others to didactics and activities of environmental education.

Last, the social and cultural hunting component, since always sensitive, in a protected area as well, to the health of the typical Alpine fauna populations, looks favourably to the reintroduction of a species that can diminish the predation of Galliformes and Lagomorphae by the golden eagle.

Historic presence and causes of extinction

In the south-eastern portion of the Alpine chain (the southern Dolomites and the pre-Alpine Veneto-Carnic belt) the marmot got extinguished in pre-historic times, i.e. before written documents could be possible. The bone and fur remnants which came to light in those areas during palaeontology excavations (Dal Piaz, 1929; Bressan, 1988; Tonon, 1989; Bon et al., 1991; Cappato et al., 2006; Gurioli et al., 2006) testify how, locally too, the species had been actively hunted since as far as pre-history. It is probable that the extinction of the species from Veneto and Friuli prairies was in great part the consequence of such hunting activities, together with the low altitude post-glacial climate dynamics. Above all, since in these areas the high altitude prairie is fragmented and takes on an insular distribution, with small islands of prairie separated and isolated by deep, extensively forested valleys. All this prevented a spontaneous re-colonization, a fact which probably avoided a similar extinction in the central and western Alps, the latter being characterized by a greater and more continuous extension of high altitude prairies.

Added to this factor, the reduced size and greater isolation of the Eastern Alpine populations brought with them a progressive loss in genetic diversity (Kruckenhauser & Pinsker, 2004), which, might, at least in theory, have affected negatively the vitality of the populations.

Today we can consider one of the main reasons for marmot extinction, hunting, to have been removed, considering that the species is protected on the national territory by the Law 157/92. The problem of isolation and the reduced size of the populations in the south-eastern part of the Alpine arc is still open, with the consequent problem of greater inbreeding rates and the issue on the entity of their effects. A problem heightened in cases of re-introduction (Lapini & Borgo, 2004), in which a "founder's effect" takes place, i.e. a sort of initial genetic bottle neck. The loss of genetic diversity and its effect on the vitality of the new populations represents a stimulating research feature for the management and future preservation of the reintroduced populations in the Eastern Alpine area.

Methods

The project of reintroduction was preceded by a study of feasibility aimed at individuating eligible areas inside the Park, quantifying their actual environment suitability and the potential number of populations possibly to be reintroduced, at individuating the areas of origin, the capturing system and the number of marmots to be reintroduced, and finally at monitoring the dynamics of colonization and the success of the project. Borgo, 2007; Borgo et al., 2008).

For the capture of animals, the Stelvio National Park (Passo dello Stelvio, BZ) and the Northern Dolomites (Passo Pordoi and Cherz plateau, BL) were selected. These areas are 100 km distant from each other and host large sized populations (> 300 ind.), and were chosen in order to guarantee animals with low inbreeding rates. In order to increase the genetic diversity of the founders, in each reintroduction area the introduction of animals from both populations was scheduled.

At the time of capture, which was carried out by using string traps, each animal was labelled on its left ear with a coloured label identifying its family of origin, and on its right ear with a label identifying its gender.

Starting from the first releases, for the whole duration (three years) of the project, in collaboration with the C.T.A. of the Corps of Forest Rangers, a periodical monitoring was effected of the introduced animals' distribution, of their survival and the productivity of the new couples. All observations were mapped on the orthophotos (scale 1: 5.000) and successively reported on GIS.

Four areas resulted eligible for the Marmot inside the park: the Vette Feltrine territory (65-70 potential family nuclei), Cimonega-Erera-Agnelezze (55-60 potential nuclei), Gardesana-Pramper-Talvena (40-45 potential nuclei) and La Schiara-Serva (14-16 potential nuclei). In the last two areas, which have already been the object of a preceding reintroduction test conducted by the Belluno Province, the species was already present, although with non-quantified quotas. The project, therefore, started reintroduction in the first two areas, characterized by the absence of the species and by a greater eligibility.

The marmots necessary to the reintroduction project were captured in 2006 and 2007. For each of the two years the capture of twenty marmots in the Stelvio Park and of just as many at Pordoi and Cherz was planned. In the two-year course 2006-2007, 81 marmots were introduced into the Park. In 2006 the 20 marmots captured at Pordoi (22nd -23rd of May) were introduced in the area of Erera on the 23rd and24th of May, whereas the 21 coming from the Stelvio (24th -26th of May) were released in Busa Grande delle Vette on the 26th and 27th . In 2007, instead, the 20 marmots captured at Pordoi (28th -30th of May) were released on the Vette (29th -31st of May) while those captured at the Stelvio (22nd -24th of May) were released in the Cimonega-Erera area (23rd -24th of May).

The capturing operations in the Belluno area were conducted with the collaboration of officers of the Provincial Police (Hunting and Fishing Office), while those at the Stelvio were directly conducted by the researchers of the Dolomiti Bellunesi National Park and by the CTA officers of the Corps of Forest Rangers. All the captured animals were weighed , classified according to sex and age, and labelled with small sized coloured ear labels. Each animal was marked with a label for each ear, according to a five-coloured marking code suitable for recognizing each animal's sex and family of origin, in order to be able to follow the settling in dynamics more precisely, and define an optimal distribution for the animals released during the second year.

The releasing of captured animals was carried out as soon as possible, contemporarily to the capturing operations, in order to reduce the time of captivity to the minimum possible. The marmots, closed inside screened cages, were transferred to the Park by means of motor vehicles, and transported to the release sites with off-road vehicles belonging to the Park and the CTA, and on shoulder. In 2007, some animals for Cimonega and Agnelezze were transported to their destination by means of the helicopter of the CFS (Corps of Forest Rangers).

The release cages were always opened in front of excavations or natural cavities amidst rocks, so that the animals could find an immediate refuge in which to settle and recover from the detention stress, before venturing out in the open land. After releasing the animals, the operators always withdrew immediately, so as not to induce deleterious escape reactions in the animals. For the same reasons, territory explorations in search of the introduced animals always began only a few days after release.

During the first year, it was preferred to release all the animals in a single zone for each reintroduction area: the surroundings of Malga Erera and the Busa Grande delle Vette. This in order to minimize the risk that the initial spreading of animals might take to their reciprocal isolation.

During the second year releasing was carried out in several sites, according to what advised by the distribution of the animals released the previous year. In fact, the second introduction was finalized, on one side to facilitate the colonization of new areas, on the other to provide a partner for the marmots who had remained single during the previous year. The first objective was pursued by releasing the animals directly in the new areas to be colonized, where some artificially dug burrows had been purposely created in order to facilitate the animals' settling on the spot. The second objective was achieved by releasing the new potential partners directly into the burrows of animals which had remained single. This was possible thanks to the labelling of the marmots, which enabled us to recognize the gender of lone animals.

The marmots released in 2006 in Erera came from 12 families, with a consequent withdrawal of 1.7 individuals from each captured family. The animals released on the Vette Feltrine in 2006 came from 7 families, with a consequent average withdrawal of 3 individuals from each captured family. The animals belonging to a same family were released within the same site, in order to facilitate the persistence of existing cohesive forces as much as possible, and thus reduce the number of animals doomed to remain alone. Isolated animals, in fact, especially when females, have scanty probabilities of surviving.

The process of colonization

In the days immediately following the releases, the animals spread over the reintroduction areas, in search of sites where to settle. In 2006, when the reintroduction area was still uninhabited, the average distance of spreading from the point of release was greater in males (average= 1047 m, max = 3300 m) than in females (average = 665 m, max = 1295 m). The same distance was greater in Erera (average = 1330 m, max = 3300 m) than on the Vette (average = 622 m, max = 1070 m). In 2007, the different and more dot-like release strategy recommends us not to compare the data.

After a month from the 2006 release, the new-born population of Erera had colonized an area (minimum convex polygon over the burrows) of 651 ha, building up 11 active settlements. At the same time the population on the Vette occupied an area equal to 154 ha and consisted of 8 active settlements. At the end of summer, on the Vette one nucleus was missing, as it had been exterminated by a family of foxes (cf. § Mortality) which had usurped their burrow. In the spring of 2007, the extinction of two other nuclei on the Vette and one in Erera was registered. The successive releases allowed re-colonizing all vacant nuclei, emphasizing the importance of reintroducing animals through successive releases.

In June 2006, 61% of settlements were represented by couples of different sex, 33% by lone animals. In only one case (6%) a group of more than two animals (a couple and a young male) was formed, consisting of three individuals belonging to three different families of origin. All the animals which had settled by themselves were males of Erera: on the Vette at the end of June no animal resulted in being alone. It is interesting to observe how males settling alone moved away to a greater distance from the site of release (1619 m; ES 359) than did the males settling with a female (665 m; ES 105). Was their greater distancing the cause of their solitude, since females spread at lower distances, or was their distancing the consequence of not finding available females? The first hypothesis seems more probable, also keeping in mind that, as the distance from the spot of release increases, the probabilities of an encounter diminish, and that at release the ratio between the two genders was 1:1.

The labelling of animals allowed verifying whether there was a tendency by individuals of the same family to join together again. In the whole group of two populations, it was found that 77.6% of the homo-familiar couples that might potentially have formed did effectively settle together. After the 2007 releases an increase in the density of both populations was found, but not a significant increase in the settling area, rising to 180 ha on the Vette and even shrinking to 399 ha in the populations of Erera, on account of the disappearance of the settlement at Agnelezze.

Mortality

In a population of marmots, two are the main causes of mortality: predation during spring and summer, and freezing to death in winter. In a consolidated population the incidence of such factors normally does not exceed 15%, but may reach higher values, even 80%, in young animals (Da Silva et al., 2006), in spreading individuals (Frey-Ross, 2003), and in populations being reintroduced. Predation is in fact made easier by the lack of social organization, the scantiness of shelters, and the marmots' exploring activities. Winter mortality is increased by the scarce number of animals hibernating together (Arnold et al., 1991) and by the difficulties in digging and preparing an adequate winter burrow.

Among the animals released in 2006, the average summer mortality was 39%, greater on the Vette (42,8%) than in Erera (35%). While in the latter area mortality was wholly concentrated within the first two weeks after release, on the Vette it was protracted for the whole summer. The stream of disappearances is seemingly due to predation by a female fox with her three cubs. This fox had settled in a large marmot burrow, after devouring the burrow's owners (predation remnants were found). During all inspections the fox was observed ambushing near one, in turn, of the settlements of the Busa Grande delle Vette. In one occasion, an attack was deliberately foiled by the project responsible, who intervened in "defence" of a marmot.

During the first hibernation or in the days immediately following its end, a further mortality took place, summing up to 14.3% on the Vette and 15% in Erera. During the summer on the Vette no further losses took place, whereas in Erera a marmot was predated by a golden eagle and a second disappeared after being turned out by a marmot released in 2007. At the end of summer 2007 the overall mortality of the animals introduced in 2006 was 57% (9 individuals surviving) on the Vette and 50% (10 individuals surviving) in Erera.

The summer mortality of the animals introduced in 2007 was greater: 50% on the Vette and 60% in Erera. The increase appears to be seemingly due to a greater predation, allowed by the greater experience especially of the golden eagle, compared to the previous year. Confirming this, in 2006 no attack by the eagle was observed, while in 2007 3 attacks were observed, one of which crowned by success (for the eagle).

Reproduction

The monitoring of reproduction in the two populations gave exceptional and definitely encouraging results. Already in 2006 a female of the Erera population managed to nurse two babies, despite the fact that delivery took place in the first 10 days after introduction. An exceptional event, probably allowed by the good availability of natural (carsic) cavities, present in the site of release, and by the fact she could settle in with a male adult of the same family of origin (her partner?). At the end of summer 2006 only one of the two small ones was present.

GRAFICI (usare quelli del poster,grafici A e B)

Dynamics of the populations reintroduced in the districts of the Vette Feltrine (population A) and of Erera (population B).

During 2007, in Erera 21 babies were born and all the couples (4) formed in 2006 reproduced themselves (5.2 small ones /couple), including the one who had given birth in 2006: an exceptional event since normally in nature marmots give birth to babies every second year. On the Vette 11 babies were born (3.7 babies/couple) but only two of the three couples surviving intact gave birth to babies: the couple which had settled in with a sub-adult male did not reproduce themselves. In compensation, though, a female that had settled in by herself gave birth to a baby. Apparently, after hibernation she mated with a male of one of the two neighbouring nuclei. A case of extra pair copulation by a single. Another interesting fact: the male introduced in 2007 who formed a couple with this female, accepted her small ones without killing them, as , instead, quite frequently happens when a new male conquers a territory (Coulon et al., 1995). During 2007, in the two populations, therefore, 32 babies were born, with the average size of the brood being of 4.6 babies: a value higher than the average data reported in the Literature (Allainé, 2004), a thing which gives good hopes for a rapid growth of the population.

Communication activities

In parallel with the scientific reintroduction project, a communication campaign was carried out, to spread the results of the activities and create a personal and "affective" bond between residents and beneficiaries of the protected area (especially younger people) and the marmots.

The marmot was thus used as an instrument for spreading a greater environmental awareness.

Besides the traditional press bulletins on the local and national media, a "referendum" was carried out to give a name to the released animals and to the newly born.

The operation was successful, so much as to be taken up again by the radio programme "Il ruggito del coniglio" (The roar of the rabbit) by RAI Radio 2, which launched a poll among listeners on its website, in order to "baptize" the marmots.

With the collaboration of the local TV Telebelluno, a special 20 minutes report was made, illustrating the stages of capturing, labelling and releasing of the animals, and which was successfully broadcasted and replicated.

The TG2 also dedicated a report to the project, which was broadcasted on the 1st of June 2007.

An entire page of the Park's bulletin "Tracce", sent in 56,000 copies to the over 102,000 residents in the 15 townships of the Park (equal to 48.5 % of the residents in the province of Belluno), was dedicated to the reintroduction of the marmot.

The project was also inserted in the environmental education programmes "A scuola nel Parco",(At school in the Park), together with the laboratory "Anch'io sono una marmotta" (I, too, am a marmot), dedicated to nursery school children and to the children of the first two-year Primary school courses. The didactic activity envisages having children experiencing the typical day of a marmot, coping with the problem of finding food, recognizing the sentinels' alarm whistles, escaping in time inside the burrow, and correctly preparing for the long winter hibernation.

For the three-year Primary school courses and for Middle and High schools, the laboratory "Il Parco delle marmotte" (the Park of the marmots) was, instead, ideated. This laboratory, starting from the animals' ecology and behaviour, gives a deeper insight into the importance and reasons for the reintroduction project, extending the research into stories and legends having the marmots as protagonists.

Inside the Park's website www.dolomitipark.it this section is dedicated to the project.

Finally, besides the present technical report, the popular text "Marmotte alla riscossa" (Marmots at arms), illustrates the biology of the species and the reintroduction project to very young people, putting side by side very simple texts with large pictures, purposely ideated and created for this publication.