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G.M. Pastur et al. 2010. Indirect estimation of landscape uses by Lama guanicoe and domestic herbivorous
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Indirect estimation of landscape uses by Lama guanicoe and domestic
herbivorous through the study of diet composition in South Patagonia
Guillermo Martínez Pastur 1* , Rosina Soler Esteban 1 ,
María Vanessa Lencinas 1 & Laura Borrelli 2
1 Centro Austral de Investigaciones Científicas (CADIC CONICET), Argentina
2 Instituto Nacional de Tecnología Agropecuaria (INTA EEA-Bariloche), Argentina
Abstract
Herbivory is central in ecosystem function studies, and herbivores influence over regeneration
and vegetation composition through browsing. Understanding diet selection behavior along the
year is important to predict herbivore impacts on regeneration and vegetation dynamics under
different scenarios of forest and grazing management. The objective was to evaluate diet
composition of herbivorous, and correlates it to the use of different vegetation types along the
year. Study was conducted in 100 km² of Tierra del Fuego Island (Argentina) where 205
floristic surveys were obtained. Feces of native (Lama guanicoe) and domestic (Bos taurus and
Ovis aries) herbivorous were collected. Four laboratory samples per species and season were
analyzed, each one composed by five fecal collection. Samples were mixed, dried and ground in
a mill (1 mm) for micro-histological analysis. Browsing occurred all around year, where native
and domestic herbivorous alternate the uses of different environments. Native species preferred
Nothofagus pumilio forests, except in winter, where domestic species had major predominance.
Beside this, all herbivorous species included grasses in their diet, which were found in open
environments (grasslands and peatlands). The knowledge of diet and plant distribution at
landscape level allows us to propose management strategies for native and domestic
herbivorous.
Keywords: browsing, forest management, fecal micro-histological analysis, Nothofagus,
Argentina.
1. Introduction
Herbivory is central in ecosystem function studies, where large herbivores can produce
important floristic and structural changes in forested landscapes, influencing plant productivity
and species diversity (Augustine and McNaughton 1998; Skarpe and Hester 2007). In South
Patagonia, these forested landscapes are mosaics of different site types, where timber-quality
forests rarely constitute large, continuous masses since these are mixed with openlands and
associated non-timber-quality forest stands (Lencinas et al. 2008), e.g. grasslands, peat-lands,
Nothofagus antarctica forests and N. pumilio low quality forests. Beside this, the harvesting of
N. pumilio forests impacts over richness and cover of the understory (Martínez Pastur et al.
2002). For this, understanding diet selection behavior along the seasons is important to predict
herbivore impacts on regeneration and vegetation dynamics under different scenarios of forest
and grazing management. Lama guanicoe (guanaco) is the only one large native herbivore
(Bonino and Fernandez 1994), which compete with domestic herbivores across the landscape
(Bonino and Sbriller 1991). The objective was to evaluate diet composition of large herbivorous,
and correlate them to the use of different vegetation types along the year.
* Corresponding author. Tel.: +54-2901-422310 int 111- Fax.: +54+2901-430644
Email address: cadicforestal@cadic.gov.ar; cadicforestal@gmail.com
Forest Landscapes and Global Change-New Frontiers in Management, Conservation and Restoration. Proceedings of the IUFRO Landscape Ecology
Working Group International Conference, September 21-27, 2010, Bragança, Portugal. J.C. Azevedo, M. Feliciano, J. Castro & M.A. Pinto (eds.)
2010, Instituto Politécnico de Bragança, Bragança, Portugal.