Variable retention forestry conserves habitat of bird species in Patagonian Nothofagus pumilio forests

MV LENCINAS; JM CELLINI; J BENITEZ; PL PERI; G MARTÍNEZ PASTUR

Annals of Forest Research

"Marin Drăcea" National Research-Development Institute in Forestry

Lugar: Bucharest; Año: 2018 vol. 61 p. 147 - 160

1844-8135

Variable retention is an alternative harvesting system that couldbe implemented instead the more traditional ones (e.g. shelterwood cut forN. pumilio forests in southern Patagonia), because it was designed not onlyfor timber purpose, but also for conservation. However, the impact of differentretention types on diversity is not clear, e.g. stenotopic and eurytopicbird species. The objective of this work was to analyse the habitats (inside,edge or outside of aggregated retention) and the use of strata (canopy, stem,debris and floor) for different bird species under two different variable retentionharvesting types (aggregated + dispersed retentions, or aggregatedretention + clear-cuts). We analysed four years of bird observation data invariable retention harvested and unharvested forest permanent plots locatedin Tierra del Fuego province (Argentina) belonging to PEBANPA (Parcelasde Ecología y Biodiversidad de Ambientes Naturales en Patagonia Austral)network, also with understory and crown cover data. Statistical analysisincluded uni- and multivariate tests, and comparisons with unharvested forests.We inventoried nine bird species, six of which showed significantlydifferent habitat preference in variable retention types (Carduelis barbata,Phrygilus patagonicus and Tachycineta leucopyga in aggregated + dispersedretentions, and Enicognathus ferrugineus, P. patagonicus, T. leucopyga,Troglodytes aedon and Zonotrichia capensis in aggregated retention + clearcuts).Likewise, all evaluated species presented differential use of strata,and some species changed comparing harvested and unharvested forests.DCA (Detrended Corresponded Analysis) highlighted association betweenspecies and habitats (e.g. P. patagonicus is more related to outside aggregatedretentions) as well as differences between variable retention types,showing that bird species move toward edges when clear-cuts were carriedout, among aggregated retention, instead of dispersed retention. These resultssupport the effectiveness of the variable retention to conserve habitatof bird species inside managed forests, which satisfy both stenotopic andeurytopic species requirements.