Papers by Maria Andrea (Puchi) Relva
Factors facilitating and hindering the invasion of exotic conifer in Isla Victoria:
Invasive spe... more Factors facilitating and hindering the invasion of exotic conifer in Isla Victoria:
Invasive species constitute a serious threat to biodiversity, producing wide-scale changes in native communities and altering
ecosystem processes. The Andean-Patagonian forests currently exhibit a wide diversity of terrestrial as well
as aquatic introduced species. Many of these introduced species possess a high invasive potential, while at the
same time have economical relevance to the region, such as sport fishing and hunting, and pine plantations.
The described situation for Patagonia offers an ideal scenario to test and generate new hypotheses about the
ecology of tree invasions. In a more practical domain, determining the impact and knowing the relationship
between native and exotic species will permit the establishment of priorities in management actions, as well as
also avoiding or mitigating the undesirable or unexpected effects that arise from eradication or control tasks.
Here, we present a synthesis of our own studies carried out to understand the factors driving the pattern of pine
invasion in the native Nothofagus/Austrocedrus forests on Isla Victoria, Nahuel Huapi National Park. Among
studied factors, we found that some of them facilitate the invasion (e.g., introduced herbivores), while others
can delay (e.g., low presence of mycorrhizae fungi, seed predation) or have neutral effects on the invasions (e.g.,
propagule pressure). These results and others currently available from this region and elsewhere allow us to
suggest management actions to prevent or hinder a major pine invasion, which should be focused on avoiding
new introductions, reducing the abundance of introduced large mammals and preserve native ecosystems with
low levels of anthropic disturbances. At the same time, we consider important to start well designed studies
to analyze the effects of these management actions.
[Keywords: biotic resistance, invasional meltdown, mycorrhizal, native forest, non-native, propagule pressure,
ungulates]
Litter and soil properties are not altered by invasive deer browsing in forests of NW Patagonia
It is largely accepted that large mammalian herbivores can indirectly influence ecosystem propert... more It is largely accepted that large mammalian herbivores can indirectly influence ecosystem properties by changing the quantity and quality of litter inputs to soil through selective browsing on plant communities. However, idiosyncratic effects (positive, neutral and negative) have been found for different vegetation types, herbivory and soil properties. In this study we tested whether browsing by exotic deer introduced into Patagonian forests 90 years ago alters physical, chemical and biological soil properties and litter quantity and quality. As in many terrestrial ecosystems, N is the main nutrient that limits plant growth in Patagonia. Consequently, any disturbance that alters the N cycle, such as changes in the type or intensity of herbivory, is expected to affect these forest ecosystems. We compared soil and total litter from inside and outside five 7-yr old exclosures located on Isla Victoria, Parque Nacional Nahuel Huapi, Argentina. Despite introduced deer has significantly affected the composition, abundance and structure of the understory vegetation, we found no differences between browsed and unbrowsed areas in the physical (bulk density, moisture), chemical (pH, base cations, organic C and total N) and biological (potential microbial respiration and net N mineralization) soil properties. This could be attributable to the high capacity of volcanic soils to stabilize organic matter, buffering disturbance-induced changes. However, the quantity and quality (C, N and C/N ratio) of total litter were also not different between browsed and unbrowsed areas. Although non-significant differences were found between treatments in both compartments, litter and soil, most variables showed a slight trend toward higher values in unbrowsed areas. This suggests that 7 years of browsing exclusion would be not enough to detect changes induced by browsing, particularly in highly stable volcanic soils.► The effect of introduced deer on soil and litter in forests of Patagonia were studied. ► Changes on soil and total litter after 7-yr old deer exclusion were not evident. ► Short periods of measurements in volcanic soils could explain these findings.
Introduced deer reduce native plant cover and facilitate invasion of non-native tree species: evidence for invasional meltdown
Patterns of use and damage by exotic deer on native plant communities in northwestern Patagonia
Habitat use by colonial tuco-tucos (Ctenomys sociabilis): specialization, variation, and sociality
Introduced conifer invasions in South America: an update
Effects of introduced ungulates on forest understory communities in northern Patagonia are modified by timing and severity of stand mortality
Enemy release or invasional meltdown? Deer preference for exotic and native trees on Isla Victoria, Argentina
Seed predation as a barrier to alien conifer invasions
Environmental management, Jan 1, 2003
Biological Invasions, Jan 1, 2002
Biological Invasions, Jan 1, 2008
Enemy release or invasional meltdown? Deer preference for exotic and native trees on Isla Victoria, Argentina
Effects of simulated browsing on the growth of Austrocedrus chilensis saplings
Uploads
Papers by Maria Andrea (Puchi) Relva
Invasive species constitute a serious threat to biodiversity, producing wide-scale changes in native communities and altering
ecosystem processes. The Andean-Patagonian forests currently exhibit a wide diversity of terrestrial as well
as aquatic introduced species. Many of these introduced species possess a high invasive potential, while at the
same time have economical relevance to the region, such as sport fishing and hunting, and pine plantations.
The described situation for Patagonia offers an ideal scenario to test and generate new hypotheses about the
ecology of tree invasions. In a more practical domain, determining the impact and knowing the relationship
between native and exotic species will permit the establishment of priorities in management actions, as well as
also avoiding or mitigating the undesirable or unexpected effects that arise from eradication or control tasks.
Here, we present a synthesis of our own studies carried out to understand the factors driving the pattern of pine
invasion in the native Nothofagus/Austrocedrus forests on Isla Victoria, Nahuel Huapi National Park. Among
studied factors, we found that some of them facilitate the invasion (e.g., introduced herbivores), while others
can delay (e.g., low presence of mycorrhizae fungi, seed predation) or have neutral effects on the invasions (e.g.,
propagule pressure). These results and others currently available from this region and elsewhere allow us to
suggest management actions to prevent or hinder a major pine invasion, which should be focused on avoiding
new introductions, reducing the abundance of introduced large mammals and preserve native ecosystems with
low levels of anthropic disturbances. At the same time, we consider important to start well designed studies
to analyze the effects of these management actions.
[Keywords: biotic resistance, invasional meltdown, mycorrhizal, native forest, non-native, propagule pressure,
ungulates]