Variable retention forestry in Nothofagus pumilio Patagonian forests as a strategy to conserve native bird species

MARTÍNEZ PASTUR, G; CELLINI, JM; PERI, PL; LENCINAS, MV

Conferencia; International Scientific Conference INCDS; 2018

Biodiversity assemblage changed across landscape, especially birds (Martínez Pastur et al., 2015, 2016), being necessary developed land-sharing strategies. Variable retention was proposed as an alternative to achieve both timber and conservation purposes in the management of Nothofagus pumilio forests of southern Patagonia (Martínez Pastur et al., 2009). This system allowed to maintain biodiversity in managed stands (Soler et al., 2015; Lencinas et al., 2017), however is not clear which is the impact of different retention types over sensitive or generalist species that reach from open-lands (Lencinas et al., 2009; Soler et al., 2016). The objective was to analyse the use of retention (inside, edge or outside aggregates) and niches (canopy, stem, debris, and floor) within different management strategies (aggregates and dispersed retention or clear-cuts) by different bird species. We used five years observation data of a permanent plot belongs to PEBANPA network (Peri et al., 2016) located in Tierra del Fuego (Argentina). We also used understory plants variables of the same plots. Statistics included uni- and multivariate analyses (detrented correspondence analyses - DCA) and comparisons with primary unmanaged forest bird data. We analysed nine Passeriform bird species, where six of them presenting different use pattern of the retention (Carduelis barbata, Phrygilus patagonicus and Tachycineta leucopyga in aggregated and dispersed retention, and P. patagonicus, T. leucopyga, Zonotrichia capensis, Enicognathus ferrugineus and Troglodytes aedon in aggregated and clear-cuts). Beside this, all the species presenting special niche requirements, and some changes were observed when we compared the results with the primary unmanaged forests. DCA showed that the studied species differently used the retention types (e.g. Elaenia albiceps were it is more related to aggregates and P. patagonicus to harvested areas), and also showed that the behaviour changed according to the harvesting system employed. Birds used more the dispersed retention when it was present, and move to edges when clear-cuts were employed. These data support the effectiveness of the variable retention strategy to conserve bird species with different habitat requirement inside the managed stands.