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Providing evidence to improve practice

Individual study: Foraging by bats in cleared, thinned and unharvested boreal forest

Published source details

Patriquin K.J. & Barclay R.M.R. (2003) Foraging by bats in cleared, thinned and unharvested boreal forest. Journal of Applied Ecology, 40, 646-657


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

Retain residual tree patches in logged areas Bat Conservation

A replicated, controlled study in 1998–2000 of 18 deciduous, coniferous and mixed forest sites in Alberta, Canada (Patriquin & Barclay 2003) found that residual tree patches had similar activity of two bat species and lower activity of one bat species compared to forest patches that had been cleared. The activity (bat passes/hour) of little brown bats Myotis lucifugus and northern long-eared bats Myotis septentrionalis was similar within residual tree patches and clearcut patches in all three types of forest (data reported as statistical model results). The activity of silver-haired bats Lasionycteris noctivagans was lower within residual tree patches than clearcut patches in all three types of forest. In winter 1998–1999, three patches of forest were left intact (average 974–1,210 stems/ha) and three were cleared in each of three forest types (deciduous, coniferous, mixed). Each of the 18 x 10 ha patches was surrounded by a buffer of intact forest (59–471 m wide). At each of 18 sites, bat activity was recorded with bat detectors at the centre and edge of each patch in June–July 1999 and June–August 2000 for a total of 33–42 nights/site.

(Summarised by Anna Berthinussen)

Thin trees within forest and woodland Bat Conservation

A replicated, controlled, site comparison study in 1998–2000 of 36 deciduous, coniferous and mixed forest sites in Alberta, Canada (Patriquin & Barclay 2003) found that thinned tree stands had similar activity for three bat species to unthinned tree stands, but one bat species was recorded less often in thinned stands than in clearcut patches. The activity (bat passes/hour) of little brown bats Myotis lucifugus, northern long-eared bats Myotis septentrionalis and silver haired bats Lasionycteris noctivagans did not differ significantly between thinned and unthinned tree stands in any of the three types of forest (data reported as statistical model results). In all three types of forest, silver-haired bat activity was lower in thinned tree stands than in clearcut patches. Experimental forest patches (10 ha, average 974–1,210 stems/ha) were created in winter 1998–1999 with three replicates of four treatments (clearcut with no trees retained, thinned with 20% or 50% of trees retained, unthinned with 100% of trees retained) in each of the three forest types (all >50 years old). At each of 36 sites, bat activity was recorded with bat detectors at the centre and edge of each patch in June–July 1999 and June–August 2000 for a total of 33–42 nights/site.

(Summarised by Anna Berthinussen)