The viviparous lizard is Ireland’s only native lizard. Individuals vary significantly in colour, but usually have a predominantly brownish-green upper body, with two dark lateral lines, commonly edged with white or yellow. The underside is brightly coloured, generally yellow-orange, often with black markings. Newborn lizards are black, fading as they grow to bronze-brown on their upper surface and grey beneath. Adult lizards grow to approximately 15cm, roughly 60% of which is tail. A proportion of newts will have shed part of their tails at some stage during adulthood.
Life-Cycle and Behaviour:
Viviparous lizards feed predominantly on invertebrates. They tend to hibernate from late-October - February emerging in late-February/early March. They are occasionally active during warm weather in winter. This species gives birth primarily in late-July/early-August and 4-10 live young are born.
Viviparous lizards are widespread and can be found in a range of habitats. Highest population densities have been recorded in bog, heath and coastal habitats and on the margins of coniferous woodlands. They also tend to be common in a range of grassland habitats, particularly those not subject to heavy grazing pressure. They also frequent gardens and other suitable areas in urban and post-industrial sites. Lizards need access to the following features: Basking sites: often on south-facing slopes and hedge banks or areas with micro-topographic variation, and with structurally-diverse mosaics of vegetation and exposed substrates. Refuges: places of shelter including patches of dense vegetation, rock and soil fissures, log piles and mammal burrows.
Foraging areas: features with a high concentration of prey.
Hibernacula (hibernating sites): free-draining structures, usually with a sunny aspect, including refuges as described above.
Surveys for viviparous lizards will be required where suitable habitat features have been identified during the multi-disciplinary walkover survey. In circumstances where there is likely to be viviparous lizards present and where the species is widely distributed in the locality, it may be appropriate to simply assume their presence and to subsequently design mitigation accordingly.
For viviparous lizards, the key items of information that need to be collected in order to inform an EIS and design appropriate mitigation are: (i) the presence or absence of the species within habitats that will be directly affected by the works; (ii) assuming they are present, the distribution of lizards within the survey corridor; (iii) the apparent ‘health’ and viability of the lizard population (e.g. evidence of breeding in current or recent seasons and the proportion of animals carrying wounds or with missing tails); (iv) identification of potentially important features (e.g. hibernation sites); and (v) an assessment of the likely value of the different habitats in the survey corridor for lizards.
Whilst it can be helpful to make use of artificial refuges, direct observation-based surveys tend to be most effective in detecting viviparous lizards. Surveys should therefore commence with direct observations, only making use of artificial refuges as an additional measure when required to provide the all the information listed above. In order to reliably infer absence from a site it is necessary to repeat the survey visits between 5 and 10 times during appropriate weather conditions (see Group-Specific Survey Techniques) and during the months viviparous lizards are active. Clearly if all of the data required is obtained during the first few visits, the survey can be curtailed.
Optimum Survey Period:
The best months in which to reliably find viviparous lizards are April to mid-/late-May, and mid- /late-August to mid-September, depending upon the weather conditions at the beginning and end of each period. Hazy or intermittent sunshine are the best conditions, however bright sunshine early in the day during cool weather is also suitable. Surveys are not appropriate during cold or wet periods.
Mitigation, compensation and enhancement:
Capture and relocation operations for this species can be extremely labour-intensive and in most cases, the most efficient approach is to cut and rake vegetation during warm weather. This is displaces the resident lizards prior to earthworks or other activities that could result in accidental mortalities. Whether or not reptile-proof fencing is subsequently required to exclude lizards depends on site-specific conditions.