Colonization of spoil benches of an opencast lignite mine in northwest Spain by amphibians and reptiles

Abstract

Colonization by reptiles and amphibians of the spoil benches of the Meirama opencast lignite mine in northwest Spain was studied over the 10 years following the start of the revegetation process. At Meirama, spoil benches are initially fertilized and hydroseeded with a pasture mix, but are subject to little subsequent management and are gradually colonized by scrub vegetation characteristic of the region. Herpetofauna censuses were carried out (1) yearly on a single 2 ha plot over the 6 years following hydroseeding, and (2) in a single year on ten 2 ha plots which had been hydroseeded between 0 and 10 years previously. In addition, censuses were carried out on three undisturbed ‘control’ plots close to the mine. Fifteen species (nine amphibians and six reptiles) were detected in one or more of the spoil-bench plots. Recolonization is particularly rapid after the first 2–3 years post-hydroseeding, and is clearly closely related to habitat development due to revegetation and natural succession. The first reptile species to colonize the study plots was Podarcis bocagei (first year), and the first amphibians Alytes obstetricans and Rana perezi (second year). Species composition was most similar to that in control plots in the oldest (ten-year-old) spoil plots.