Rákosi vipera (Vipera ursinii rakosiensis)

Description
Adults average 40−50 cm in length, although specimens of 63−80 cm have been reported.
The meadow viper is a small venomous snake with a beautiful and intricate zigzag pattern marking the length of its back. The basic body colour is a light grey to brown along the sides, usually with a paler band down the centre of the back, within which a dark zigzag with black edging appears. Occasionally, strongly yellow-coloured scales can occur around these markings. A dark ‘V’ shaped mark appears on the top of the head and there is a dark stripe behind the eye. The underside of the body ranges from black to dark grey or even reddish, often with grey-white speckles. Females grow larger than males, and the poisonous fangs of this species are relatively short.

Habitat

This subspecies was formerly widespread on the Great Hungarian Plain.  At least 30 populations were still in existence in the 1950s, but the distribution of this snake has since been reduced to 12 populations that are found in two main areas:Hanság.  Much of this region of northwest Hungary, close to the Austrian border, has been converted to agriculture and forestry on an enormous scale.  About 6,000 ha of mainly damp, low-lying peaty habitats have been protected, but the distribution of the meadow viper within this area is now confined to a single 9 ha site (Újvári et al 2000).  A tiny population of less than 50 snakes remains here and exhibits many signs of severe inbreeding depression (Újvári et al 2002);
Kiskunság.  Most of the remaining populations of Vipera ursinii rakosiensis survive in this area of highly fragmented meadow-steppe (puszta) habitats in central Hungary, between the Danube and Tisza rivers (Újvári et al 2000).
This region contains the once extensive ‘pusztapeszerdacs’ in the north and the Kiskunság National Park to the south.  The Park, the northernmost point of which lies about 30 km south of Budapest, protects a range of lowland habitats in six separate blocks, totalling 30,628 ha, including the Bugac region occupied by Vipera ursinii rakosiensis.  Meadow vipers, which often inhabit the remnants of post-glacial sand dune systems, survive in eleven isolated populations in this area.  The sites occupied range from 100-400 ha in extent (averaging 200 ha) but only support an estimated combined total of approximately 450-950 individual snakes (Báldi et al 2001; Halpern & Péchy 2002). Regular population and habitat assessment studies carried out in the Kiskunság National Park since 1993 by BirdLife Hungary have shown rapidly decreasing population sizes and the apparent disappearance of juvenile and subadult snakes suggests a recruitment rate of close to zero at some sites (Halpern & Péchy 2002).
In an assessment of 379 Hungarian vertebrate taxa carried out by Báldi et al (2001), the meadow viper was considered to be by far the most endangered.  With a total population of only a few hundred individuals restricted to just a dozen sites, many of which show signs of terminal decline, Vipera ursinii rakosiensis clearly has an Unfavourable Conservation Status in Hungary.

Biology
The meadow viper feeds upon a variety of animal species, most commonly orthopterans (grasshoppers, crickets, etc.), followed by rodents, lizards, birds, spiders and beetles. However, significant seasonal variations in the diet exist, with invertebrates predominating only between July and September, and vertebrates playing a more important role at other times of the year. One poisonous bite is usually enough to kill the prey.
Mating occurs from April to May and females give birth to four to eight (sometimes up to 12 or 15) live young from August to September. Clutch size appears to be positively correlated with female body size.

Threats
The precise threats facing the meadow viper across its range are unknown, but habitat destruction is likely to have played an important role in the species’ decline. Recent studies have been made of the Hungarian meadow viper (V. u. rakosiensis) subspecies, which has an estimated remaining population of as low as 500 individuals and is in imminent danger of extinction. The decline of this subspecies has been largely attributed to the growth in agricultural land, which has greatly reduced and fragmented the meadow viper’s habitat. Even small barriers of farmland are thought to reduce movement and outbreeding with other populations. The subspecies is also thought to have suffered from over-collection from the wild, both for the pet trade and scientific purposes. Small, isolated populations are not only more vulnerable to extinction through stochastic events such as disease epidemics, or storms, but they are also more likely to suffer from loss of genetic diversity through inbreeding, massively increasing the risk of extinction. Loss of genetic variation can result in a high percentage of stillbirths or deformities, which have been recorded for this subspecies, and low genetic diversity is currently considered the prime threat to the subspecies

Conservation
Meadow vipers appear in a number of protected areas, including the Danube Delta Biosphere Reserve in Romania (V. u. moldavica) and Bjelasica Mountain National Park (V. u. macrops) in eastern Montenegro. Attempts are being made to preserve the very small Hungarian population of Vipera Ursinii Rakosiensis, located in protected areas, through a four year programme co-funded by the Ministry of Environment and Water Affairs and the EU LIFE-Nature fund, which focuses on four major tasks: habitat reconstruction, monitoring and related studies, a publicity campaign and the establishment of the Viper Conservation and Breeding Centre. This Centre started operating in 2004 with 10 adult snakes collected from different populations and, as of August 2005, 4 females had produced a total of 69 offspring, 25 the first year and 44 the second. These vipers will hopefully be released into selected habitat in the future. Should the release of these snakes into the wild prove successful, captive breeding could be a viable option for the effective conservation of the other subspecies, including V. u. moldavica. The fact that the Hungarian meadow viper appears to breed well in captivity is therefore extremely encouraging and provides new hope for the meadow viper’s future survival.