Ecological modelling of habitat use and the annual activity patterns in an urban population of the tortoise, Testudo hermanni

Abstract

The Hermann's tortoise (Testudo hermanni) is increasingly threatened in Western Europe and in Italy because of habitat loss, pollution, and illegal removal of free‐ranging individuals for the pet trade. Hence, the conservation and appropriate management of the various populations is mandatory, and the few remnant, isolated populations inhabiting urban parks and heavily altered landscapes may be particularly important. An urban population of Hermann's tortoises was studied by capture–mark–recapture procedures in an ‘urban green area’ in Rome (‘Insugherata’ Natural Reserve), between March 2001 and October 2005. A spatial modelling approach (logistic regression, with forward stepwise addition model) was developed to investigate which proximate landscape factors influenced the presence/absence of the tortoises. Eight different variables were considered for this model. We found that a single variable (SHRUBS, i.e. Mediterranean dry macchia‐like vegetation) was positively correlated to the presence of tortoises, and one to their absence (ECOTONE, i.e. ecotone area constituted by different types of shrubs growing on a relatively wet substratum). The tortoise activity deviated significantly from the null hypothesis of an equal activity throughout the year, with the higher peaks of activity in May, June, and August, and reduced activity in March and April. The conservation implications of our study were also discussed.