Effectiveness of fencing and hunting to control Lama guanicoe browsing damage: Implications for Nothofagus pumilio regeneration in harvested forests

MARTÍNEZ PASTUR, G; SOLER, R; IVANCICH, H; LENCINAS, MV; BAHAMONDE, HA; PERI, P

JOURNAL OF ENVIRONMENTAL MANAGEMENT

ACADEMIC PRESS LTD-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2016 vol. 168 p. 165 - 174

0301-4797

Browsing damage bynative ungulates is often to be considered one of the reasons of regenerationfailure in Nothofagus pumilio silvicultural systems. Fencing and hunting inforests at regeneration phase have been proposed to mitigate browsing effects.This study aims to determine effectiveness of these control methods inharvested forests, evaluating browsing damage over regeneration, as well asclimate-related constraints (freezing or desiccation). Forest structure andregeneration plots were established in two exclosures against native ungulates(Lama guanicoe) by wire fences in the Chilean portion of Tierra del Fuegoisland, where tree regeneration density, growth, abiotic damage and quality(multi-stems and base/stem deformation) were assessed. Exclosures did notinfluence regeneration density (at the inicial stage with < 1.3 m high, and at theadvanced stage with >1.3 mhigh). However, sapling height at 10-years old was significantly lower outside(40e50 cm high) than inside exclosures (80e100 cm), and also increased theirannual height growth, probably as a hunting effect. Likewise, quality wasbetter incide exclosures. Alongside browsing, abiotic conditions negativelyinfluenced sapling quality in the regeneration phase (20%e28% of allseedlings), but greatly to taller plants (as those from inside exclosure). Thishighlights the importance of considering climatic factors when analysingbrowsing effects. For best results, control of guanaco in recently harvestedareas by fencing should be applied in combination with a reduction of guanacodensity through continuous hunting. The benefits of mitigation actions (fencingand hunting) on regeneration growth may shorten the regeneration phase periodin shelterwood cutting forests (30e50% less time), but incremental costs mustbe analysed in the framework of management planning by means of long-termstudies.