Montado management effects on the abundance and conservation of reptiles in Alentejo, Southern Portugal

摘要

This study was carried out in the Iberian-Mediterranean region of Alentejo (Southern Portugal) to discover which ‘montado’ management practices significantly affected reptile variables (abundance, richness). Field surveys on 30 sampling plots allowed us to identify 370 individuals distributed among 12 terrestrial reptile species (six lizards, one amphisbaenid and five colubrid snakes). The lizard Psammodromus algirus was the dominant species (n = 297 individuals). The highest species richness was comprised of five species, whilst two or three species were recorded in two-thirds of the sampling plots. Principal component analysis over management variables accounted for 71.8% of the total variance and subsequently helped to reveal four agrosilvopastoral types. Among them, the highest reptile abundance largely overlapped the cork oak montado, while higher cattle stocking rates were estimated (trampling index) to occur in the holm oak areas, affecting significantly the reptiles. Regression models also showed that both reptile abundance and richness were significantly related to montado areas, where the shrub layer is well preserved and cattle are either absent or present at low stocking rates. Adequate management of montado, preserving the shrub patchwork, is crucial for the conservation of reptiles. Livestock stocking rates should also be maintained at a sustainable level of 0.2–0.4 cattle/ha.