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Providing evidence to improve practice

Action: Ensure connectivity between habitat patches Bird Conservation

Key messages

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  • A replicated, controlled study in Canada found significantly higher abundances of some birds, but not forest specialists, in forest patches connected to a continuous area of forest, than in isolated patches.
  • Another study of the same system found evidence that corridors were used by some bird species more than clearcuts between patches, although corridors near cut forest were not used more than those near uncut stands.

Supporting evidence from individual studies

1 

A replicated, controlled study in boreal forests in 1993-5 in Alberta, Canada (Machtans et al. 1996), found that significantly higher abundances of the ten most common understorey birds were found in three riparian corridors between forest patches than in three clearcuts between patches. Only two of the ten were found nesting or foraging in clearcuts. In addition, significantly more juveniles used corridors following logging, than before, but only in one site. No more birds used the buffer strips near logged forest than similar strips near un-logged forest, when controlling for local abundances. Corridors consisted of 1-5-m of riparian vegetation and 90-110 m of forest. Visual surveys were used in clearcuts and mist nets in corridors.

2 

A replicated, controlled study as part of the same study as Mactans et al. (1996) in mixed boreal forests in northern Alberta, Canada (Hannon et al. 2002), found significantly higher abundances of resident songbirds and woodpeckers, but not of forest specialists, in forest plots connected to a continuous block when compared to isolated fragments. Resident species were found at similar abundances in connected fragments and unfragmented forests, whilst habitat generalists were found at similar abundances across all forest types. None of the individual species analysed appeared to benefit from connectivity. Forest fragments were 10 or 40 ha, either in continuous forest, isolated by a 200 m strip of clearcut on all sides or isolated on three of four sides for connected fragments. Three replicates of each treatment were established in the winter of 1993-4 and monitored until 1998.

Referenced papers

Please cite as:

Williams, D.R., Child, M.F., Dicks, L.V., Ockendon, N., Pople, R.G., Showler, D.A., Walsh, J.C., zu Ermgassen, E.K.H.J. & Sutherland, W.J. (2019) Bird Conservation. Pages 141-290 in: W.J. Sutherland, L.V. Dicks, N. Ockendon, S.O. Petrovan & R.K. Smith (eds) What Works in Conservation 2019. Open Book Publishers, Cambridge, UK.