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McDougall K.L.,Climate Change and Water | Alexander J.M.,ETH Zurich | Haider S.,TU Munich | Pauchard A.,University of Concepción | And 4 more authors.
Diversity and Distributions | Year: 2011

Aim We use data from 13 mountain regions and surrounding lowland areas to identify (1) the origins, traits and cultural uses of alien plant species that establish in mountains, (2) the alien species that are most likely to be a threat and (3) how managers might use this information to prevent further invasions.Location Australia, Canada, Chile, India, New Zealand, South Africa, Spain, Switzerland, USA. Methods Lists of alien species were compiled for mountains and their surrounding or nearby lowlands. Principal co-ordinates analysis was performed on a matrix of similarities created using presence/absence data for alien species. The significance of differences between means for (1) similarity metrics of lowland and mountain groups and (2) species traits of lowland and mountain alien floras was determined using t-tests. In seven of the 13 mountain regions, lists of alien species undergoing management were compiled. The significance of differences between proportions of traits for species requiring and not requiring management input was determined with chi-square tests.Results We found that the proximal lowland alien flora is the main determinant of a mountain region's alien species composition. The highest similarities between mountain floras were in the Americas/Pacific Region. The majority of alien species commonly found in mountains have agricultural origins and are of little concern to land managers. Woody species and those used for ornamental purposes will often pose the greatest threat. Main conclusions Given the documented potential threat of alien species invading mountains, we advise natural resource managers to take preventive measures against the risk of alien plant invasion in mountains. A strategy for prevention should extend to the surrounding lowland areas and in particular regulate the introduction of species that are already of management concern in other mountains as well as climatically pre-adapted alien mountain plants. These may well become more problematic than the majority of alien plants currently in mountains. © 2010 Blackwell Publishing Ltd.


Visser V.,Stellenbosch University | Langdon B.,University of Concepción | Langdon B.,Institute of Ecology and Biodiversity IEB | Langdon B.,Bioforest S.A. | And 3 more authors.
Biological Invasions | Year: 2014

Distribution data are central to many invasion science applications. The shortage of good information on the distribution of alien species and their spatial dynamics is largely attributable to the cost, effort and expertise required to monitor these species over large areas. Virtual globes, particularly Google Earth, are free and user-friendly software which provide high-resolution aerial imagery for the entire globe. We suggest this has enormous potential for invasion science. We provide suggestions and tools for gathering data on the distribution and abundance of invasive alien trees using visual interpretation of Google Earth imagery, and propose how these data may be used for a number of purposes, including calculating useful metrics of invasions, prioritising species or areas for management and predicting potential distributions of species. We also suggest various practical uses of Google Earth, such as providing a tool for early detection of emerging invasions, monitoring invasions over time, and to help researchers and managers identify suitable field study sites. Virtual globes such as Google Earth are not without limitations and we provide guidance on how some of these can be overcome, or when imagery from Google Earth may not be fit for invasion science purposes. Because of Google Earth's huge popularity and ease of use, we also highlight possibilities for awareness-raising and information sharing that it provides. Finally, we provide the foundations and guidelines for a virtual global network of sentinel sites for early detection, monitoring and data gathering of invasive alien trees, which we propose should be developed as part of a "citizen science" effort. There has been limited use of virtual globes by invasion scientists and managers; it is our hope that this paper will stimulate their greater use, both within the field of invasion science and within ecology generally. © 2013 Springer Science+Business Media Dordrecht.


Meserve P.L.,Northern Illinois University | Kelt D.A.,University of California at Davis | Previtali M.A.,Cary Institute of Ecosystem Studies | Milstead W.B.,U.S. Environmental Protection Agency | And 2 more authors.
Journal of Mammalogy | Year: 2011

Since 1989 we have monitored small mammal populations at a semiarid site in north-central Chile with a large-scale livetrapping grid complex. Selective exclusions of vertebrate predators or putative small mammal competitors, or both, have yielded relatively small or mostly transitory effects, or both, on small mammal population dynamics and plant community composition. During the study period 5 El Niohigh rainfall episodes have occurred lasting 13 years. Resident or core small mammals such as Abrothrix olivaceus, Phyllotis darwini, and Octodon degus experience dramatic fluctuations during and following rainfall pulses. Temporary resident or opportunistic species such as Oligoryzomys longicaudatus and A. longipilis disappear from the thorn scrub for varying periods of time. All species persist in more mesic nearby habitats near dry stream courses (aguadas). Since a 3-year high rainfall event in 20002002 mean annual rainfall has increased in this region, mainly due to a lack of prolonged droughts. Under these conditions, and building on a qualitative model proposed by Noy-Meir, long-lived species might become more abundant. Changes in the small mammal assemblage are consistent with these predictions; O. degus, a caviomorph rodent with a long life span, now comprises a more constant proportion of the small mammal biomass in the thorn scrub, and we have documented reduced variation in species diversity. Increased rainfall, a predicted consequence of global climate change in this region, might be leading to changes in small mammal assemblage structure and composition and ultimately will result in a more stable, less oscillatory assemblage in the thorn scrub. Additionally, invasive groups such as introduced lagomorphs and ephemeral plants might become more abundant in this community. The long-term consequences of changes in rainfall patterns due to El Nio Southern Oscillations (ENSOs), with important teleconnections to global-scale phenomena, will lead to diverse changes at the community level here. © 2011 American Society of Mammalogists.


Carcamo P.F.,Católica del Norte University | Carcamo P.F.,Institute Fomento Pesquero | Garay-Fluhmann R.,University of La Serena | Gaymer C.F.,Católica del Norte University | Gaymer C.F.,Institute of Ecology and Biodiversity IEB
Ocean and Coastal Management | Year: 2013

The implementation of ecosystem-based management usually develops from existing institutional and governance arrangements in a given area. Therefore, it is necessary to analyze the institutional framework of a region or country to assess whether this framework is compatible and whether it will promote or potentially hinder the implementation of new management strategies. This paper explores the possibilities and constraints of institutional frameworks (represented by legislation) concerning the possible implementation of ecosystem-based management of the Chilean coast. We evaluated the functional fit between a conceptual ecosystem defined by stakeholders (and based on ecosystem services, threats and uses/activities) and Chilean legislation related to coastal and marine resource planning and management. First, we measured the functional fit between the defined ecosystem and legislation through a quantitative analysis based on text revision and network analysis. Second, we evaluated different management, conservation and planning instruments existing in Chilean legislation, with respect to their suitability for the implementation of ecosystem-based management. We found that Chilean legislation rarely accounts for relationships defined between the different components of the ecosystem model. We observed low functional fit potential and many gaps in legislation. However, we found that certain existing instruments in the current legislation can be used as a foundation for implementing management based on the principles and criteria of ecosystem-based management (e.g., Multiple-Use Coastal Marine Protected Areas). © 2013 Elsevier Ltd.


Gonzalez A.L.,University of Santiago de Chile | Gonzalez A.L.,Institute of Ecology and Biodiversity IEB | Farina J.M.,University of Santiago de Chile | Farina J.M.,Brown University | And 4 more authors.
Oikos | Year: 2011

Key processes such as trophic interactions and nutrient cycling are often influenced by the element content of organisms. Previous analyses have led to some preliminary understanding of the relative importance of evolutionary and ecological factors determining animal stoichiometry. However, to date, the patterns and underlying mechanisms of consumer stoichiometry at interspecific and intraspecific levels within natural ecosystems remain poorly investigated. Here, we examine the association between phylogeny, trophic level, body size, and ontogeny and the elemental composition of 22 arthropod as well as two lizard species from the coastal zone of the Atacama Desert in Chile. We found that, in general, whole-body P content was more variable than body N content both among and within species. Body P content showed a significant phylogenetic signal; however, phylogeny explained only 4% of the variation in body P content across arthropod species. We also found a significant association between trophic level and the element content of arthropods, with carnivores having 15% greater N and 70% greater P contents than herbivores. Elemental scaling relationships across species were only significant for body P content, and even the P content scaling relationship was not significant after controlling for phylogeny. P content did decrease significantly with body size within most arthropod species, which may reflect the size dependence of RNA content in invertebrates. In contrast, larger lizards had higher P contents and lower N:P ratios than smaller lizards, which may be explained by size-associated differences in bone and scale investments. Our results suggests that structural differences in material allocation, trophic level and phylogeny can all contribute to variation in the stoichiometry of desert consumers, and they indicate that the elemental composition of animals can be useful information for identifying broad-scale linkages between nutrient cycling and trophic interactions in terrestrial food webs. © 2011 The Authors. Oikos © 2011 Nordic Society Oikos.


McCluney K.E.,Arizona State University | Belnap J.,U.S. Geological Survey | Collins S.L.,University of New Mexico | Gonzalez A.L.,University of Santiago de Chile | And 7 more authors.
Biological Reviews | Year: 2012

Species interactions play key roles in linking the responses of populations, communities, and ecosystems to environmental change. For instance, species interactions are an important determinant of the complexity of changes in trophic biomass with variation in resources. Water resources are a major driver of terrestrial ecology and climate change is expected to greatly alter the distribution of this critical resource. While previous studies have documented strong effects of global environmental change on species interactions in general, responses can vary from region to region. Dryland ecosystems occupy more than one-third of the Earth's land mass, are greatly affected by changes in water availability, and are predicted to be hotspots of climate change. Thus, it is imperative to understand the effects of environmental change on these globally significant ecosystems. Here, we review studies of the responses of population-level plant-plant, plant-herbivore, and predator-prey interactions to changes in water availability in dryland environments in order to develop new hypotheses and predictions to guide future research. To help explain patterns of interaction outcomes, we developed a conceptual model that views interaction outcomes as shifting between (1) competition and facilitation (plant-plant), (2) herbivory, neutralism, or mutualism (plant-herbivore), or (3) neutralism and predation (predator-prey), as water availability crosses physiological, behavioural, or population-density thresholds. We link our conceptual model to hypothetical scenarios of current and future water availability to make testable predictions about the influence of changes in water availability on species interactions. We also examine potential implications of our conceptual model for the relative importance of top-down effects and the linearity of patterns of change in trophic biomass with changes in water availability. Finally, we highlight key research needs and some possible broader impacts of our findings. Overall, we hope to stimulate and guide future research that links changes in water availability to patterns of species interactions and the dynamics of populations and communities in dryland ecosystems. © 2011 The Authors. Biological Reviews © 2011 Cambridge Philosophical Society.


Salinas F.,University of Santiago de Chile | Salinas F.,Institute of Ecology and Biodiversity IEB | Armesto J.J.,University of Santiago de Chile | Armesto J.J.,Institute of Ecology and Biodiversity IEB
Botanical Journal of the Linnean Society | Year: 2012

Ecological and evolutionary studies of the epiphytic growth habit in angiosperms are limited. In this article, we assess the relationship between growth habit and regeneration niche in Coronanthereae (Gesneriaceae) and discuss its implications for the evolution of epiphytism in this lineage. In the temperate rainforest of southern Chile, we quantified the vertical distribution and experimentally examined the regeneration niche of three endemic species of Coronanthereae. One species was a holoepiphyte, which was more frequent in the upper canopy, and two species were secondary hemiepiphytes, which decreased in abundance with tree height. Seed germination of the holoepiphyte was higher on tree bark substrates and under open canopy than on forest soil and in the shade. In contrast, seed germination of both secondary hemiepiphytes did not differ between substrates (bark vs. soil) or light conditions (light vs. shade). Seedling survival percentage of secondary hemiepiphytes was higher on forest soil and under a closed canopy, thus behaving as shade-tolerant species. In turn, the holoepiphyte behaved as a shade-intolerant species. The reconstruction of the ancestral growth habits and regeneration niches on the inferred phylogenetic tree of Coronanthereae revealed that the specialized regeneration niche of Sarmienta repens, characterized by requirements of shade intolerance and germination on tree bark, was coupled with the evolution of the holoepiphytic growth habit. We conclude that differentiation in the regeneration niche is a key process in the evolution of epiphytic growth habits in Coronanthereae. © 2012 The Linnean Society of London.


Reid S.,University of Santiago de Chile | Reid S.,Institute of Ecology and Biodiversity IEB | Armesto J.J.,University of Santiago de Chile | Armesto J.J.,Institute of Ecology and Biodiversity IEB
Plant Ecology | Year: 2011

Effects of avian gut-passage on seed germination are important to assess the effectiveness of frugivores in woodland regeneration, particularly in biodiversity hotspots that have a high incidence of avian frugivory. We examined the effect of avian gut-passage on seed germination in contrast to seeds that remain uneaten in five shrub species in Mediterranean central Chile and sought to determine the physiological mechanism(s) by which seed germinability is modified. Germination assays were conducted in a glasshouse for five common shrub species of the sub-Andean matorral: Azara dentata (Flacourtiaceae), Schinus polygamus and Schinus molle (Anacardiaceae), Cestrum parqui (Solanaceae), and Maytenus boaria (Celastraceae). We estimated germinability (final percent germination), dormancy length (time from sowing to first germination), mean length of dormancy of all germinated seeds, and contrasted germination rates of defecated versus manually extracted and pulp-enclosed seeds. Avian gut-passage increased seed germinability in four of the five shrub species studied-primarily through deinhibition via pulp removal. Minimum dormancy length was not modified by avian gut-passage for A. dentata, but was significantly shorter for S. molle and C. parqui. Mean dormancy length was significantly shorter in gut-passed seeds of A. dentata, S. molle and M. boaria. Avian gut-passage greatly enhanced the seed germination rates of three species, A. dentata, S. molle and C. parqui. We conclude that the positive effects of birds on seed germination facilitate the regeneration of sub-Andean shrublands, and that bird declines due to landscape change may impair recovery rates of successional or restored areas due to dispersal limitation. © 2010 Springer Science+Business Media B.V.


Bustamante-Sanchez M.A.,University of Santiago de Chile | Armesto J.J.,University of Santiago de Chile | Armesto J.J.,Institute of Ecology and Biodiversity IEB | Halpern C.B.,University of Washington
Journal of Ecology | Year: 2011

Most studies of tree regeneration are limited to particular environments and may not capture variation in the biotic or abiotic factors that regulate recruitment at larger spatial scales. Critical processes such as competition and facilitation can vary spatially, along gradients in resource availability and environmental stress, and temporally, with plant development. We examined patterns of natural tree recruitment and experimentally followed germination and seedling survival of five tree species (pioneer to late seral) in three early successional communities of contrasting bio-physical environments in a rural landscape on Chiloé Island, Chile. We quantified natural recruitment of juveniles and saplings and assessed relationships between tree density and local environment. We used a removal experiment to test the influence of early successional vegetation on seed germination and early survival of tree species. In each community, seeds and seedlings were placed in paired experimental plots from which vegetation was removed or left intact (control). To identify potential correlates of germination and seedling survival, we measured light transmittance and soil properties in each plot. In all communities, established vegetation had either a positive or neutral effect on germination and/or survival although responses varied among life stages and species. Germination and survival were correlated with the lower levels of light in controls, consistent with negative correlations between natural tree densities and light. Vegetation cover was not dense enough to facilitate survival of late successional species, but not too dense to inhibit survival of shade-intolerant or mid-tolerant species. Among communities, natural densities of juveniles were greatest under conditions where experimental germination rates were highest. Seedling height growth was lowest in the community characterized by waterlogged soils, consistent with the naturally low transition rate from juveniles to saplings and a negative correlation between density of shade-intolerant trees and soil moisture. Synthesis. Our experiments indicate strong, mostly positive controls (facilitation) on tree recruitment in early seral shrublands with differing bio-physical environments. Benefits of shading are manifested at different stages in the life history. However, community context is critical: variation in seasonal patterns of soil moisture may explain spatial variation in the density and size structure of natural tree recruitment. © 2010 The Authors. Journal of Ecology © 2010 British Ecological Society.


Bustamante-Sanchez M.A.,University of Concepción | Armesto J.J.,University of Santiago de Chile | Armesto J.J.,Institute of Ecology and Biodiversity IEB
Journal of Applied Ecology | Year: 2012

Re-establishment of native forest species in rural landscapes may be conditioned by the proximity of seed sources, the post-disturbance composition of successional patches and the seed dispersal patterns of frugivores. Knowledge of seed dispersal rates into early seral communities, and how these are influenced by the structural and compositional characteristics of these communities is still quite poor. We used an observational approach to quantify the seed rain and seed limitation (SL) (proportion of sites to which seeds were not dispersed) of woody species during two growing seasons in three early successional shrublands with contrasting species composition and attractiveness to frugivores on Chiloé Island, Chile. We compared species immigration based on dispersal types (bird- vs. wind dispersed) and life-form (shrubs vs. trees). Concomitantly, we used an experimental approach to test whether artificial perches would relieve SL and enhance seed dispersal and seedling establishment of fleshy-fruited species. Most seeds collected were of pioneer shrubs already present in the early successional sites. Few (5%) were from trees appearing only in the surrounding second-growth forest. Density of seeds from fleshy-fruited trees and shrubs was seven times higher in the seral community most attractive to frugivores, whereas density of seeds from wind-dispersed trees was similar among communities. Artificial perches significantly increased the density and species richness of seeds from fleshy-fruited trees in all communities, but the magnitude of the facilitation effect depended on the ecological context of each seral community. Seed rain enhancement was higher in the community less attractive to frugivores. Seedling recruitment, however, remained low even under perches, indicating that additional constraints act during seed germination and/or seedling survival and growth. Synthesis and applications. Forest succession in this rural landscape may be delayed or arrested by extremely low seed rain, despite the proximity (<100 m) of seed sources in older forest patches. Although artificial perches significantly enhance inputs of bird-dispersed tree seeds into shrublands, especially where fleshy-fruited pioneer species are absent from the seral community, they do not overcome other site-related barriers to establishment, as the lack of shaded places and limited soil drainage. Thus, in some ecological contexts, multiple approaches, such as direct seeding or planting, and the use of nurse plants, may be required to enhance seed rain and seedling establishment of fleshy-fruited species. © 2012 The Authors. Journal of Applied Ecology © 2012 British Ecological Society.

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