Bird guilds show different responses to tree retention levels: a meta-analysis

Abstract

Since the introduction of retention forestry in the 1990s, its practice has spread in the boreal and temperate regions. Its benefits for biodiversity are well recognised, and usually presented in the form of aggregated results for each taxonomic group. However, ameliorating effects of increased levels of retention on species with different ecological requirements is still not well studied. With this meta-analysis, we aim at disentangling the response of different bird guilds, considering the level of retention applied, as well as other confounding factors, such as the forest type or harvested area. We used a systematic review protocol and collected 30 studies which compared the response of birds to a gradient of retention levels against unharvested forests and/or clearcuts. Firstly, we compared the overall response of the full bird assemblage to retention, and found no differences in abundance and species richness between retention and unharvested forest, except for the abundance of some forest specialist species. Secondly, assessing the responses of various guilds showed that each bird guild can be affected very differently, according to their life history, biome, forest type and, most importantly, retention intensity. Results allow us to infer minimum retention levels needed to preserve each bird guild, admitting that other factors can play an important role in shaping the bird assemblage, often in interaction with retention. For example, canopy and cavity nesters showed a more positive response to lower levels of retention in mixed or broadleaved forests than in conifer forests. Our results indicate that minimum retention levels ranging between 40 and 60% of original habitat are needed, in order to maintain the same bird assemblage as in the autochthonous unharvested forest, with particular regard to the forest specialists. (C) 2019 The Authors. Published by Elsevier B.V.

Keywords

Forest birds; Forest management; Forest specialists; Selective harvest; Retention forestry

Published in

Global Ecology and Conservation
2019, Volume: 18, article number: e00615Publisher: ELSEVIER SCIENCE BV

SLU Authors

• Mikusinski, Grzegorz

  • Department of Ecology, Swedish University of Agricultural Sciences
    
  • University of Freiburg

UKÄ Subject classification

Ecology
Forest Science
Zoology


Publication identifier

DOI: https://doi.org/10.1016/j.gecco.2019.e00615

Permanent link to this page (URI)

https://res.slu.se/id/publ/100545