Browsing by Author "Lopez, Daniela N."

Now showing 1 - 7 of 7
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    A bug's tale: revealing the history, biogeography and ecological patterns of 500 years of insect invasions
    (2023) Lopez, Daniela N.; Fuentes-Contreras, Eduardo; Ruiz, Cecilia; Ide, Sandra; Estay, Sergio A.
    The arrival of Europeans to the Americas triggered a massive exchange of organisms on a continental scale. This exchange was accelerated by the rapid increase in the movement of people and goods during the 20th century. In Chile, scientific and technical literature contains hundreds of records of non-native insect spe-cies established in different parts of the territory, from the hyperarid Atacama Desert to the Magallanes Region. Here, we analyse temporal trends, taxonomic diversity, biogeographic origin and main impacts of these species on different sectors in Chile from the European arrival to the present. Our task includes a review of old records in museum catalogues, libraries, collections, expedition records and catalogues. Al-most 600 species of non-native insects have been reported to be established in Chile. Introductions started with the very arrival of Europeans to the central valley of Chile and underwent a huge acceleration in the second half of the 20th century. The order Hemiptera was the most prevalent amongst non-native insects. Most species are linked to agriculture and forestry. Species are of Palearctic origin in more than 50% of the records. In terms of temporal trends, the rate of established non-native species shows an abrupt increase at the beginning of the 1950s. This change may be associated with the strong development in agriculture and forestry in Chile after World War II and the increase in intercontinental air traffic. We believe that the understanding of past patterns of introductions is an important component in the design of current policies to minimise the impact of invasive insects.
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    A modeling approach to estimate the historical population size of the Patagonian Kawesqar people
    (2022) Estay, Sergio A.; Lopez, Daniela N.; Silva, Carmen P.; Gayo, Eugenia M.; McRostie, Virginia; Lima, Mauricio
    The study of human-gatherers societies' demography used to be a difficult task due to the lack of direct evidence to support the estimations. This is the case of several human groups from Pacific Patagonia whose historical population size estimations are controversial. This study estimated the historical population size for the Kawesqar people using direct and indirect evidence. Thus, we collated past estimations from experts and encounter rates distribution in time and space to generate a statistical approximation for population size. We used weights to include the reliability of such past estimations under three modeling scenarios. Our results indicate that the historical population ranged roughly between 3700 and 3900 individuals before the massive contact with Chileans and European people. The approach developed here for combining and integrating different evidence for estimating population in Kawesqar people, emerges as a promising and valuable tool to study the demography of other hunter-gatherer societies in South America.
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    Can suitability indices predict plant growth in the invaded range? The case of Acacias species
    (2023) Silva, Carmen P.; Lopez, Daniela N.; Naulin, Paulette I.; Estay, Sergio A.
    IntroductionForestry in many parts of the world depends on exotic species, making this industry a source of invasions in some countries. Among others, plantations of the genus Pinus, Eucalyptus, Acacia, Populus, and Pseudotsuga underpin the forestry industry and are a vital component of many countries economies. Among woody plants, the cosmopolitan genus Acacia includes some of the most commonly planted trees worldwide. In order to prevent, manage and control invasive plant species, one of the most used tools is species distribution models. The output of these models can also be used to obtain information about population characteristics, such as spatial abundance patterns or species performance. Although ecological theory suggests a direct link between fitness and suitability, this link is often absent. The reasons behind the lack of this relationship are multiple. Chile is one of the countries where Acacia species, in particular, A. dealbata and A. melanoxylon, have become invaders. MethodsHere, we used climatic and edaphic variables to predict thepotentially suitable habitats for A. dealbata and A. melanoxylon in continental Chile and evaluate if the suitability indices obtained from these models are associated with the observed performance of the trees along the country. ResultsOur models show that variable importance showed significant similarities between the variables that characterize each species' niche. However, despite the high accuracy of our models, we did not observe an association between suitability and tree growth. DiscussionThis disconnection between suitability and performance can result from multiple causes, from structural limitations, like the lack of biotic interactions in the models, to methodological issues, like the usefulness of the performance metric used. Whatever the scenario, our results suggest that plans to control invasive species should be cautious in assuming this relationship in their design and consider other indicators such as species establishment success.
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    Disentangling the spread dynamics of insect invasions using spatial networks
    (2023) Estay, Sergio A.; Silva, Carmen P.; Lopez, Daniela N.; Labra, Fabio A.
    Introduction: Describing and understanding spatiotemporal spread patterns in invasive species remains a long-standing interdisciplinary research goal. Here we show how a network-based top-down approach allows the efficient description of the ongoing invasion by Drosophila suzukii in Chile.
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    Integrating species and interactions into similarity metrics: a graph theory-based approach to understanding community similarity
    (2019) Lopez, Daniela N.; Camus, Patricio A.; Valdivia, Nelson; Estay, Sergio A.
    Community similarity is often assessed through similarities in species occurrences and abundances (i.e., compositional similarity) or through the distribution of species interactions (i.e., interaction similarity). Unfortunately, the joint empirical evaluation of both is still a challenge. Here, we analyze community similarity in ecological systems in order to evaluate the extent to which indices based exclusively on species composition differ from those that incorporate species interactions. Borrowing tools from graph theory, we compared the classic Jaccard index with the graph edit distance (GED), a metric that allowed us to combine species composition and interactions. We found that similarity measures computed using only taxonomic composition could differ strongly from those that include composition and interactions. We conclude that new indices that incorporate community features beyond composition will be more robust for assessing similitude between natural systems than those purely based on species occurrences. Our results have therefore important conceptual and practical consequences for the analysis of ecological communities.
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    Stability of rocky intertidal communities, in response to species removal, varies across spatial scales
    (2021) Valdivia, Nelson; Lopez, Daniela N.; Fica-Rojas, Eliseo; Catalan, Alexis M.; Aguilera, Moises A.; Araya, Marjorie; Betancourtt, Claudia; Burgos-Andrade, Katherine; Carvajal-Baldeon, Thais; Escares, Valentina; Gartenstein, Simon; Grossmann, Mariana; Gutierrez, Barbara; Kotta, Jonne; Morales-Torres, Diego F.; Riedemann-Saldivia, Barbara; Rodriguez, Sara M.; Velasco-Charpentier, Catalina; Villalobos, Vicente, I; Broitman, Bernardo R.
    Improving our understanding of stability across spatial scales is crucial in the current scenario of biodiversity loss. Still, most empirical studies of stability target small scales. We experimentally removed the local space-dominant species (macroalgae, barnacles, or mussels) at eight sites spanning more than 1000 km of coastline in north- and south-central Chile, and quantified the relationship between area (the number of aggregated sites) and stability in aggregate community variables (total cover) and taxonomic composition. Resistance, recovery, and invariability increased nonlinearly with area in both functional and compositional domains. Yet, the functioning of larger areas achieved a better, albeit still incomplete, recovery than composition. Compared with controls, smaller disturbed areas tended to overcompensate in terms of total cover. These effects were related to enhanced available space for recruitment (resulting from the removal of the dominant species), and to increasing beta diversity and decaying community-level spatial synchrony (resulting from increasing area). This study provides experimental evidence for the pivotal role of spatial scale in the ability of ecosystems to resist and recover from chronic disturbances. This knowledge can inform further ecosystem restoration and conservation policies.
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    Transient species driving ecosystem multifunctionality: Insights from competitive interactions between rocky intertidal mussels
    (2024) Betancourtt, Claudia; Catalan, Alexis M.; Morales-Torres, Diego F.; Lopez, Daniela N.; Escares-Aguilera, Valentina; Salas-Yanquin, Luis P.; Buchner-Miranda, Joseline A.; Chaparro, Oscar R.; Nimptsch, Jorge; Broitman, Bernardo R.; Valdivia, Nelson
    Anthropogenic biodiversity loss poses a significant threat to ecosystem functioning worldwide. Numerically dominant and locally rare (i.e., transient) species are key components of biodiversity, but their contribution to multiple ecosystem functions (i.e., multifunctionality) has been seldomly assessed in marine ecosystems. To fill this gap, here we analyze the effects of a dominant and a transient species on ecosystem multifunctionality. In an observational study conducted along ca. 200 km of the southeastern Pacific coast, the purple mussel Perumytilus purpuratus numerically dominated the mid -intertidal and the dwarf mussel Semimytilus patagonicus exhibited low abundances but higher recruitment rates. In laboratory experiments, the relative abundances of both species were manipulated to simulate the replacement of P. purpuratus by S. patagonicus and five proxies for ecosystem functions-rates of clearance, oxygen consumption, total biodeposit, organic biodeposit, and excretion-were analyzed. This replacement had a positive, linear, and significant effect on the combined ecosystem functions, particularly oxygen consumption and excretion rates. Accordingly, S. patagonicus could well drive ecosystem functioning given favorable environmental conditions for its recovery from rarity. Our study highlights therefore the key role of transient species for ecosystem performance. Improving our understanding of these dynamics is crucial for effective ecosystem conservation, especially in the current scenario of biological extinctions and invasions.