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Providing evidence to improve practice

Individual study: Community composition and activity of insectivorous bats in Mediterranean olive farms

Published source details

Herrera J.M., Costa P., Medinas D., Marques J.T. & Mira A. (2015) Community composition and activity of insectivorous bats in Mediterranean olive farms. Animal Conservation, 18, 557-566


This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.

Reduce pesticide, herbicide or fertiliser use Bat Conservation

A replicated, site comparison study in 2010 of 36 Mediterranean olive farms in southwestern Portugal (Herrera et al. 2015) found that traditional farms using few or no chemicals had greater bat activity and different compositions of bat species than intensive farms using high chemical inputs, but they did not differ significantly from semi-intensive farms. Bat activity overall was higher in traditional farms (average 6 bat passes/night) than intensive farms (1 bat pass/night). Species composition also differed (data reported as Sørenson’s index). No significant differences in bat activity or species composition were found between traditional and semi-intensive farms (average 3 bat passes/night). At least eight bat species were recorded (see original paper for data for individual species). Thirty-six olive farms (13 traditional, 12 semi-intensive and 11 intensive) were surveyed. Traditional farms used few or no chemicals, semi-intensive farms used a moderate chemical input and intensive farms used high and frequent chemical inputs (dimethoate and deltamethrin). Tree density and the use of mechanical methods varied between farms. Three olive farms (one per management type) were simultaneously surveyed every night for one week between July and September 2010 with a bat detector deployed in the centre of each farm.

(Summarised by Anna Berthinussen)