How much has the mammal fauna in Estonia changed?

 

The number of known mammal species in Estonia has increased by 30% since the end of World War II, from 46 to 66 species. There are many reasons for this change. Firstly, some species have probably lived here for a long time, but they have not been discovered before. Secondly, some species have arrived in Estonia quite recently, either independently or with the help of humans. Thirdly, the application of new methods is constantly changing perceptions of mammalian taxonomy and the composition of local fauna: the systematic belonging of species has been reassessed or several species have been identified instead of just one.

Humans have introduced alien and repopulated species into the fauna

The first muskrat (Ondatra zibethicus) of North American origin was introduced into a limited area of two small lakes in the Kolga forest district of Harju County in Estonia already in 1933. This attempt to raise fur animals failed and the animals were released into the wild [1]. Muskrats were later more successfully and much more widely populated in 1947. Then, with the purpose of enriching the hunting fauna, 195 muskrats caught from the shores of Lake Ladoga were released in six water bodies: Lakes Saadjärv, Soitsjärv, Raigastvere, and Elistvere as well as Ulila River and Emajõgi River [2]. These muskrats reproduced successfully and the emerging populations began to expand rapidly. In the early 1990s, the entire Eastern European muskrat population was hit by a sudden destruction, both in terms of numbers and range, for reasons that are still unclear.

 

A large number of raccoon dogs (Nyctereutes procyonoides) of Far Eastern origin were released into the Estonian wilderness in 1950. However, the first three raccoon dogs had been hunted in South-Eastern Estonia long before that: they were caught in 1938 on the island of Kamenka in Lake Pskov (behind the current line of control), in 1947 near Lasva at the Kaku mill, and in 1949 near Võru. They were the descendants of raccoon dogs previously populated in the Pskov region and Latvia [2]. In the autumn of 1950, 80 raccoon dogs from the Kalinin oblast were released into the Pikknurme and Põlula forest districts and the Puhtu peninsula.

 

In 1956, nine Caspian red deer (Cervus elaphus altaicus) were brought to the Vääna forest district in Harju County [3]. However, after the repopulation of the European subspecies of the red deer and their rapid spread, there was a risk that the specimens of the two subspecies could cross, so the decision was made to remove the last Caspian red deer from the wild. The last three Caspian red deer were hunted in 1984.

 

In 1957, 10 beavers (subspecies Castor fiber belorussicus) caught in Belarus were released into the Jägala basin, but they could not adapt to the local conditions and most likely perished. Around the same time, the beaver also crossed Lake Lämmijärv into the streams of South-Eastern Estonia. They belonged to the subspecies C. f. osteuropaes [3]. The population of South-Eastern Estonia began to expand its range, and more came across the Narva River and along the Koiva River. In addition, in the 1970s, beavers were also introduced into the wild within Estonia [4].

 

In the spring of 1965, 16 European red deer (Cervus elaphus elaphus) from the Voronezh oblast were introduced into the wild. Eight of them were placed in the Vigala deer garden, four animals were released on the island of Abruka, and three in the Loode oak forest in Saare County. In Vigala and Abruka, the number of deer increased rapidly, and in 1970, part of the Vigala red deer population was moved to Hiiu County [3]. The population of mainland Estonian red deer has evolved from the nine animals that escaped into the wild from the Mustjärve deer garden in Viru County in 1987 and later from the deer that came to us from Latvia. By now, red deer can be found in all counties.

 

The American mink (Neovison vison) has not been deliberately introduced into the wild, but it was kept in numerous fur farms across Estonia. The animals that escaped from the farms, but also those that came from neighbouring countries, have developed into a population of American mink living in the wild. The first literary reference on American mink living in the wild comes from Matsalu in 1979 [5], [6]. The authors note that the mink were common in Matsalu already in the early 1960s. At present, the American mink is widespread in mainland Estonia, but is absent from Saaremaa and Hiiumaa [7].

 

The spotted deer (Cervus nippon) and the fallow deer (Dama dama) have not been released into the wild in Estonia – they have arrived here from neighbouring areas. Spotted deer were seen for the first time in the first half of the 1980s in Virumaa [8]. The first fallow deer was registered in Estonia in 2012 in Põlva County [9].

 

Changes in the range as a cause of increase in mammalian fauna

The range of a species changes as ecological conditions and climate change. Due to changes in range limits, new species are moving to new areas, including Estonia.

 

After World War II, research on smaller mammals gained momentum. Thus, in 1947, the presence of the pond bat (Myotis dascyneme) in Estonia was confirmed. It was observed in large numbers during the winter in underground passages in Laagri near Tallinn [10].

 

In 1982, the first two masked shrew (Sorex caecutiens) were caught in Järvselja [11]. To date, data has been collected on the presence of the masked shrew throughout mainland Estonia in a scattered manner.

 

The European pine vole (Microtus subterraneus) was first detected in Estonia in 1986 [12]. However, after the publication of an article on the first finding of the pine vole, it became clear that three years earlier, two unidentified voles had been caught, which then turned out to be pine voles. In the course of further research, the pine vole has been found in many places in mainland Estonia.

 

The first sighting of the beech marten (Martes foina) dates back to 1989, when a specimen was found after being hit by a car in Viljandi [13]. A few years later, beech martens were also caught in Pärnu County. Today, the beech marten is widespread in much of mainland Estonia.

 

In the 1990s, ultrasound-converting detectors began to be used in bat research. This allowed bat species to be identified without catching them. Analysing the ultrasound recordings of 2000, in 2001, the presence of the common pipistrelle (Pipistrellus pipistrellus s.str.) in Estonia was confirmed. In 2006, the presence of its sibling species, the soprano pipistrelle (P. pygmaeus), was also confirmed [14]. The presence of the lesser noctule (Nyctalus leisleri) and the western barbastelle (Barbastella barbastellus) has also been identified only by ultrasound detector recordings.

 

In 2013, the jackal (Canis aureus) was added to the Estonian mammal fauna when the first specimen was caught in Ullaste, near Matsalu [15]. According to the locals, they had heard ‘strangely howling foxes’ there as early as since 2010. In 2013, another new species was discovered for Estonia – the Mediterranean water shrew (Neomys anomalus). However, the most recent finding is the wood lemming (Myopus schisticolor) from 2019.

 

One-off findings include the Eurasian least shrew (Sorex minutissimus) in 1971 [16], the edible dormouse (Glis glis) in 1979 [17], and the 1970 finding of the tundra vole (Microtus oeconomus) [18]. However, there is no verifiable evidence for the first two.

 

Over time, various changes have been made in the mammalian systematics. Changes in species identification methodologies have brought new knowledge. In several cases, it has become clear that two species, or sometimes more, that are very similar in appearance have been considered to be one species. If such species are distinguished, both scientific Latin and Estonian names must be specified. Thus, a distinction was made between the sibling species of the common vole (Microtus arvalis) and East European vole (M. levis) in 1972. Two species of bats – the whiskered bat (Myotis mystacinus) and the Brandt’s bat (M. brandtii) – have been considered separate species since 1969. In the 1980s, when the hedgehog genus system was specified, common European hedgehogs were divided into two species. Now, there are already three types of hedgehogs in Europe. In Estonia, the European hedgehog (Erinacus europaeus) and the northern white-breasted hedgehog (E. roumanicus) can be found. According to the collected observational data, the northern white-breasted hedgehog is predominant in South-Western and South-Eastern Estonia. From the late 1980s, a distinction is also made between the Apodemus sylvaticus s.str. and the A. microps.

 

Species have also disappeared from the list of Estonian mammal fauna

The only species, or rather a subspecies, that has become extinct in Estonia is the Caspian red deer, which was once populated here. For a long time, there have been no verifiable evidence of wolverines (Gulo gulo) and harbour porpoises (Phocoena phocoena) who have sometimes visited in the past. No evidence of the hazel dormouse (Muscardinus avellanarius) and garden dormouse (Eliomys quercinus) has been found for decades. The European mink (Mustela lutreola) is also retreating. The wild mink population became extinct in the mid-1990s. Since 2016, a natural mink population has emerged in Hiiu County due to the breeding of minks under artificial conditions in the Tallinn Zoo and their introduction into the wild in Hiiu County.

 

Full article in the March 2020 issue of Eesti Loodus, pages 12-21

 

By: Uudo Timm, Tiit Maran

Edited for Loodusveeb by: Reigo Roasto

 

 

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[15] Männil, Peep 2013. Šaakal – oma või võõras? Eesti Jahimees 5: 20–22.

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