SOIL ACIDIFICATION NEGATIVELY AFFECTS EMBRYONIC DEVELOPMENT OF FLEXIBLE-SHELLED LIZARD EGGS

Many reptile species dig underground nests where they deposit eggs with flexible and permeable shells that have physical contact with the soil and are highly permeable to soil water and gases. Iberian rock lizard eggs (Lacerta monticola cyrenni) incubated in acidic substrates suffered significant impairment to their development. Therefore, soil pollution could be affecting embryonic development. Low pH had a negative effect on egg water exchange, hatchling size and locomotor performance. In all cases, pH had no effect on incubation duration and embryo survival. At substrate pH of 4 and 10, eggs absorbed less water and final egg size and weight was lower than at neutral pH. Hatchlings from eggs incubated in acidic substrates had lower mass (up to 28 % of weight), SVL, and tail length than controls. Running speed - a good indicator of lizard fitness - was also affected by substrate pH. Embryos incubated at pH 4 ran slower than controls. The alteration of the water absorption process that low substrate pH had on eggs during incubation partially explained the observed effects on hatchling characteristics. These sublethal effects may influence the survival or success of juveniles during or after their first wintering.