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Providing evidence to improve practice

Individual study: Managed forests in the western Cascades: the effects of seral stage on bat habitat use patterns

Published source details

Erickson J.L. & West S.D. (1996) Managed forests in the western Cascades: the effects of seral stage on bat habitat use patterns. Pages 215-227 in: R.M.R. Barclay & R.M. Brigham (eds.) Bats and Forests Symposium. British Columbia Ministry of Forests, Victoria.


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

Thin trees within forest and woodland Bat Conservation

A replicated, site comparison study in 1993–1994 of 24 forest sites in the Cascade mountains, USA (Erickson & West 1996) found that thinned tree stands of two different ages had higher bat activity than young unthinned tree stands, but lower bat activity than clearcut stands. Significantly more bat passes were recorded in 10–13 year old thinned stands (average 2 bat passes/night) and mature thinned stands (4 bat passes/night) than in young unthinned stands (no bat passes). However, fewer bat passes were recorded in both thinned stands than in clearcut stands (8 bat passes/night). At least five bat species were recorded (see original reference for data for individual species). Six replicates of tree stands in four post-harvest stages were sampled: thinned stands (10–13 year old Douglas fir Pseudotsuga menziesii), mature thinned stands (51–62 year old Douglas fir or western hemlock Tsuga heterophylla), young unthinned stands (30–40 years old, high tree density with varied tree diameter), clearcut stands (2–3 years post-harvest, 1–2 m high Douglas fir seedlings). At each of 24 sites, bat detectors recorded bat activity for six nights in July–September 1993 and 1994.

(Summarised by Anna Berthinussen)