Impacts of introduced large herbivores on Austrocedrus chilensis forests in northern Patagonia, Argentina

Relva, María Andrea; Veblen, Thomas T.

doi:10.1016/s0378-1127(97)00313-7

Cited by 76 publications

(74 citation statements)

References 13 publications

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“…Moreover, previous work has not considered how these effects change according to the major environmental and social factors that can influence use of forests at the landscape scale, namely forest successional stage and land tenure regime. For example, in South America, the few published studies have focused on analysing the impacts of introduced mammals on single forest species, such as Nothofagus dombeyi (Veblen et al 1989(Veblen et al , 1992, Austrocedrus chilensis (Veblen et al 1992, Relva and Veblen 1998, Relva and Sancholuz 2000, and Araucaria araucana (Zamorano-Elgueta et al 2012). Understanding the impacts of these disturbances on forest communities and how they vary according to forest successional stage and land tenure provides more comprehensive information to guide conservation efforts.…”

Section: Introductionmentioning

confidence: 99%

The differential influences of human‐induced disturbances on tree regeneration community: a landscape approach

et al. 2014

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Abstract. Understanding the processes shaping biological communities under interacting disturbances is a core challenge in ecology. Although the impacts of human-induced disturbances on forest ecosystems have been extensively studied, less attention has been paid to understanding how tree regeneration at the community level responds to such disturbances. Moreover, these previous studies have not considered how these effects change according to major social and environmental factors that can influence forest use at a landscape scale. In this study, we investigate the effects of cattle grazing and selective logging on the composition of tree regeneration communities in relation to forest successional stage and land tenure regime in Chilean temperate forests, a global biodiversity hotspot. We recorded seedlings, saplings and basal area of stumps of tree species (as a surrogate for selective logging), and number of cattle dung pats (as a surrogate for cattle pressure) in 129 25 3 20 m plots in small (,200 ha) and large properties in different successional stages (old-growth, intermediate, secondary forests). The regeneration of the ten more abundant species as predicted by human disturbance, land tenure, forest successional stage, and number of parent trees was modelled using generalised linear models. Predictions for each individual model were made under different scenarios of human disturbance. The predicted regeneration results were assembled and subjected to ordination analyses and permutation multivariate analyses of variance to determine differences in regeneration composition under each scenario. In most cases, best-fit models contained at least one of the explanatory variables accounting for human disturbance. The effects of selective logging on tree regeneration varied depending on land tenure regime, but cattle grazing always exhibited a negative effect. Our results revealed that cattle have a more negative effect on forest regeneration than selective logging, especially in old-growth forests and small properties. Our analytical approach contributes to the understanding of the differential influence of human-induced disturbances on the tree regeneration community at a landscape scale. It can inform conservation policies and actions, which should focus on addressing the main disturbance factors and on developing strategies to conserve the most sensitive species to such disturbances.

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Section: Introductionmentioning

confidence: 99%

The differential influences of human‐induced disturbances on tree regeneration community: a landscape approach

et al. 2014

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“…In each SU, feces and cattle trails were counted in order to estimate pasturing and trampling intensity by the cattle (Relva and Veblen, 1998). Stumps were counted in order to estimate logging intensity in the fragments.…”

Section: Methodsmentioning

confidence: 99%

Environmental variables and tree population structures in deciduous forests of central Brazil with different levels of logging

Vieira

Scariot

2008

Braz. arch. biol. technol.

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“…This is so because it forages on a highly diverse range of food sources (González et al, 2006a), having developed physiological and morphological adaptations for including in its diet a high proportion of woody species (Searle & Shipley, 2008). In continental Patagonia, the negative impacts of understory grazing by domestic and wild ungulates has been considered as one of the most important disturbances that affect Nothofagus forests regeneration (Veblen et al, 1992;Relva & Veblen, 1998;Raffaele et al, 2011;Barrios-Garcia et al, 2012). In this region, guanacos avoid grazing on Nothofagus forests.…”

Section: Guanaco Selectivity Of Forest Understory Speciesmentioning

confidence: 99%

Guanaco’s diet and forage preferences in Nothofagus forest environments of Tierra del Fuego, Argentina

et al. 2017

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Aim of study: Guanaco (Lama guanicoe Müller), is a South American native ungulate widely distributed in Patagonia, which in the island of Tierra del Fuego (TF), extends its habitat into Nothofagus spp. forests. Within these forests, guanacos consume lenga (Nothofagus pumilio) leaves and twigs, and other understory species. The aim of this work was to determine: 1) the spring and summer diet of free ranging guanacos, and 2) which plants, grown in the forest understory, guanacos do prefer, or avoid, in these seasons of great forage abundance.Area of study: Tierra del Fuego (Argentina), on three representative areas which combined Nothofagus forests and adjacent meadows (vegas).Material and Methods: Guanacos' diet was determined by comparing epidermal and non-epidermal plant fragments with microhistological analyses of feces. The analysis was made from composite samples of fresh feces, collected at the seasons of maximum forage productivity (spring and summer).Main results: During spring, 48% of guanacos' diet was composed of lenga leaves, 30% of grass-like species, 15% of grasses, and less than 7% of herbs, shrubs, and lichens. In summer, 40% of the diet was composed of grasses, 30% of lenga leaves, 25% of grasslike species and the rest corresponded to herbs, shrubs, and lichens. Within the forest understory, guanaco selected lenga leaves and twigs, grass species were consumed according to their availability (or sometimes rejected), while other herbs were not consumed at all.Research highlights: Guanacos' consumption preference for lenga, even considering the high availability of other forages, could adversely affect forest regeneration.

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Impacts of introduced large herbivores on Austrocedrus chilensis forests in northern Patagonia, Argentina

Cited by 76 publications

References 13 publications

The differential influences of human‐induced disturbances on tree regeneration community: a landscape approach

The differential influences of human‐induced disturbances on tree regeneration community: a landscape approach

Environmental variables and tree population structures in deciduous forests of central Brazil with different levels of logging

Guanaco’s diet and forage preferences in Nothofagus forest environments of Tierra del Fuego, Argentina

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