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Marta Susana Lizarralde - One of the best experts on this subject based on the ideXlab platform.
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invasive north american beaver Castor Canadensis the distribution of mitochondrial variation across the archipelago of tierra del fuego
Mastozoología neotropical, 2010Co-Authors: Mariana Fasanella, Sebastian Poljak, Marta Susana LizarraldeAbstract:In 1946 twenty-five pairs of Castor Canadensis were introduced into the Isla Grande of Tierra del Fuego (Argentina). Thanks both to environmental conditions favorable for colonization and an absence of effective control measures, today the estimated abun- dance is about 100 000 individuals. We have conducted molecular analysis of beavers from three areas of the Archipelago of Tierra del Fuego, in order to characterize the genetic structure of the invasive population. Our results from AMOVA (F st = 0.104, p < 0.001) suggest that geographical barriers and large distances could limit gene flow among the populations. In the Tierra del Fuego National Park subpopulation, we found a positive and significant autocorrelation out to 800 m (r = 0.193, p = 0.003) and the greatest haplotype diversity (= 0.83), which can probably be explained by the control plan used in this area or by natural selection combined with greater habitat diversity. We propose using the information about the demographic spatial dynamics and the spatial genetic structure in this invasive population to design an effective control strategy.
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assessing genetic variation and population structure of invasive north american beaver Castor Canadensis kuhl 1820 in tierra del fuego argentina
Biological Invasions, 2008Co-Authors: Marta Susana Lizarralde, Mariana Fasanella, Sebastian Poljak, Graciela Bailliet, Cecilia R GiuliviAbstract:The North American beaver (Castor Canadensis) was introduced into Isla Grande de Tierra del Fuego, Argentina in 1946 as a potential source of wild fur. The species showed high growth potential, reaching close to 100,000 individuals from an original founding stock of 25 females and 25 males. Beavers adapted rapidly to their new environment and became invasive, providing an excellent model of successful adaptation of introduced populations to a new habitat. In this study, we used polymorphic mitochondrial (mt) DNA to evaluate genetic variation in the introduced beaver population from Tierra del Fuego. Nucleotide variation in partial sequences of Cytochrome b (500 bp) and 12S rRNA (421 bp) genes and the main non-coding D-loop region (521 bp) were analyzed. Our study allowed to identify 10 different mtDNA lineages in the invasive population, none of them shared among the source populations. The pattern observed is a consequence of cessation of gene flow following expansion of the founding beaver population since the time of its introduction. This approach contributes to the understanding of effects of genetic changes on survival ability and reproductive success of invasive species. It also has important management implications to invasive species.
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understorey succession in nothofagus forests in tierra del fuego argentina affected by Castor Canadensis
Applied Vegetation Science, 2006Co-Authors: Guillermo Martinez Pastur, Vanessa M Lencinas, Julio Escobar, Paula Quiroga, Laura Margarita Elvira Malmierca, Marta Susana LizarraldeAbstract:Question: Does understorey richness, cover and biomass change during succession in abandoned Castor Canadensis impoundments of riparian Nothofagus forests? Location: Magellanic Nothofagus forests at Tierra del Fuego National Park (54°50'32.4'' S, 68°32'11.5'' W), Argentina. Methods: Five meadows of different time since abandonment (1, 5, 6, 9 and 20 years ago) and two controls (pure N. pumilio and mixed N. pumilio - N. betuloides forests) were sampled. Understorey variables (species richness, cover and biomass) in beaver meadows were measured at eight plots, as well as sapling and seedlings age and height. In control treatments, ten plots on each forest type characterized forest structure. Results: Beavers alter vegetation dynamics, modifying biomass and composition of the original forest communities. Richness, cover and biomass were significantly modified when compared to the original understorey. Ferns are the most affected group, while grasses became more abundant. Many species established in the impacted sectors, which did not grow in primary forests. Trees did not regenerate in impacted areas for long periods, and many understorey original species are missing. Nothofagus forests are not adapted to support a long-term beaver impact. Conclusions: Beavers modify the original ecosystem from closed forest to a grass- and sedge-dominated meadow, due to the lack of adaptive regeneration strategies in the Nothofagus forests. The maintenance of the present level of the beaver population is not sustainable over time, due to utilized and impacted tree biomass which could not be replaced by the natural dynamics of the forest ecosystem.
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invader species in argentina a review about the beaver Castor Canadensis population situation on tierra del fuego ecosystem
Interciencia, 2004Co-Authors: Marta Susana Lizarralde, Julio Martin Escobar, Guillermo DeferrariAbstract:Marta Susana Lizarralde. Ph.D., University of La Plata (UNLP), Argentina. Researcher, Consejo de Investigaciones Cientificas y Tecnicas (CONICET), Argentina. Director, Ecogenetics Laboratory, Centro Austral de Investigaciones Cientificas (CADIC), Argentina. Address: CADIC-CONICET, CC 92, 9410 Ushuaia, Tierra del Fuego, Argentina. e-mail: mlizarralde@cpsnet.com.ar Julio Martin Escobar. Technician, Ushuaia High School, Argentina. Research Assistant, Ecogenetics Laboratory, CADIC, Argentina. Guillermo Deferrari. M.Sc., UNLP, Argentina. Research Assistant, Ecogenetics Laboratory, CADIC, Argentina. INVADER SPECIES IN ARGENTINA: A REVIEW ABOUT THE BEAVER (Castor Canadensis) POPULATION SITUATION ON TIERRA DEL FUEGO ECOSYSTEM
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caracteristicas geomorfologicas de rios de montana colonizados por Castor Canadensis en tierra del fuego argentina
Ecología austral, 2003Co-Authors: Julio Martin Escobar, A Coronato, C Mallea, C Roig, Marta Susana LizarraldeAbstract:Geomorphological characteristics of mountain watershed rivers colonized by Castor Canadensis in Tierra del Fuego, Argentina. The geomorphology of a Fuegian Andes watershed colonized by the introduced species Castor Canadensis has been analyzed. The main objective was to distinguish the physical conditions of the occupied streams. Geomorphological analysis and mapping techniques were applied; also, colonization monitoring surveys in the entire watershed was made through terrestrial and aerophotogrametrical methods. Were made aerial surveys during the autumn. Streams of first and second order and low gradient (0-6o) were those chosen by Castor Canadensis for settlement. The higher-order streams were seasonally occupied, but restricted only to their secondary landforms. The northern part of the watershed is larger in size, drainage density and stream numbers; therefore, it offers more settlement possibilities. The rivers of the lateral hanging valleys were more densely occupied than those of the slope units. Several of the conditions of rivers for Castor Canadensis settlement observed in Tierra del Fuego were similar to those observed in the Northern Hemisphere. (Keywords: watershed, geomorphology, Tierra del Fuego.)
Sebastian Poljak - One of the best experts on this subject based on the ideXlab platform.
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invasive north american beaver Castor Canadensis the distribution of mitochondrial variation across the archipelago of tierra del fuego
Mastozoología neotropical, 2010Co-Authors: Mariana Fasanella, Sebastian Poljak, Marta Susana LizarraldeAbstract:In 1946 twenty-five pairs of Castor Canadensis were introduced into the Isla Grande of Tierra del Fuego (Argentina). Thanks both to environmental conditions favorable for colonization and an absence of effective control measures, today the estimated abun- dance is about 100 000 individuals. We have conducted molecular analysis of beavers from three areas of the Archipelago of Tierra del Fuego, in order to characterize the genetic structure of the invasive population. Our results from AMOVA (F st = 0.104, p < 0.001) suggest that geographical barriers and large distances could limit gene flow among the populations. In the Tierra del Fuego National Park subpopulation, we found a positive and significant autocorrelation out to 800 m (r = 0.193, p = 0.003) and the greatest haplotype diversity (= 0.83), which can probably be explained by the control plan used in this area or by natural selection combined with greater habitat diversity. We propose using the information about the demographic spatial dynamics and the spatial genetic structure in this invasive population to design an effective control strategy.
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assessing genetic variation and population structure of invasive north american beaver Castor Canadensis kuhl 1820 in tierra del fuego argentina
Biological Invasions, 2008Co-Authors: Marta Susana Lizarralde, Mariana Fasanella, Sebastian Poljak, Graciela Bailliet, Cecilia R GiuliviAbstract:The North American beaver (Castor Canadensis) was introduced into Isla Grande de Tierra del Fuego, Argentina in 1946 as a potential source of wild fur. The species showed high growth potential, reaching close to 100,000 individuals from an original founding stock of 25 females and 25 males. Beavers adapted rapidly to their new environment and became invasive, providing an excellent model of successful adaptation of introduced populations to a new habitat. In this study, we used polymorphic mitochondrial (mt) DNA to evaluate genetic variation in the introduced beaver population from Tierra del Fuego. Nucleotide variation in partial sequences of Cytochrome b (500 bp) and 12S rRNA (421 bp) genes and the main non-coding D-loop region (521 bp) were analyzed. Our study allowed to identify 10 different mtDNA lineages in the invasive population, none of them shared among the source populations. The pattern observed is a consequence of cessation of gene flow following expansion of the founding beaver population since the time of its introduction. This approach contributes to the understanding of effects of genetic changes on survival ability and reproductive success of invasive species. It also has important management implications to invasive species.
Cecilia R Giulivi - One of the best experts on this subject based on the ideXlab platform.
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assessing genetic variation and population structure of invasive north american beaver Castor Canadensis kuhl 1820 in tierra del fuego argentina
Biological Invasions, 2008Co-Authors: Marta Susana Lizarralde, Mariana Fasanella, Sebastian Poljak, Graciela Bailliet, Cecilia R GiuliviAbstract:The North American beaver (Castor Canadensis) was introduced into Isla Grande de Tierra del Fuego, Argentina in 1946 as a potential source of wild fur. The species showed high growth potential, reaching close to 100,000 individuals from an original founding stock of 25 females and 25 males. Beavers adapted rapidly to their new environment and became invasive, providing an excellent model of successful adaptation of introduced populations to a new habitat. In this study, we used polymorphic mitochondrial (mt) DNA to evaluate genetic variation in the introduced beaver population from Tierra del Fuego. Nucleotide variation in partial sequences of Cytochrome b (500 bp) and 12S rRNA (421 bp) genes and the main non-coding D-loop region (521 bp) were analyzed. Our study allowed to identify 10 different mtDNA lineages in the invasive population, none of them shared among the source populations. The pattern observed is a consequence of cessation of gene flow following expansion of the founding beaver population since the time of its introduction. This approach contributes to the understanding of effects of genetic changes on survival ability and reproductive success of invasive species. It also has important management implications to invasive species.
Mauricio Ramirez - One of the best experts on this subject based on the ideXlab platform.
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impacto del Castor Castor Canadensis rodentia en bosques de lenga nothofagus pumilio de tierra del fuego chile
Bosque, 2008Co-Authors: Aida Baldini U, Juan Oltremari A, Mauricio RamirezAbstract:Resumen es: Castor Canadensis es un roedor de Norteamerica introducido a la porcion argentina de Tierra del Fuego en el ano 1946, invadiendo territorios chilenos del...
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impacto del Castor Castor Canadensis rodentia en bosques de lenga nothofagus pumilio de tierra del fuego chile impact of american beaver Castor Canadensis rodentia in lenga nothofagus pumilio forests of tierra del fuego chile
2008Co-Authors: Aida Baldini U, Juan Oltremari A, Mauricio RamirezAbstract:SUMMARY Castor Canadensis is a North American rodent introduced in the Argentinean part of Tierra del Fuego in 1946, invading Chilean territories located in the same area. In this zone, not only do beavers build dikes, but they also feed on arboreal material, mainly from Nothofagus pumilio. This study tried to prove that damage on both biomass and volume in the N. pumilio forest is caused by beavers. The objectives of the study were: to identify the type of damage and to quantify the loss of wood biomass and gross volume of the most abundant forest species. Results indicated that more than half of measured trees presented some damage; the highest damage being presented by N. pumilio. Loss in biomass reaches almost 15 t ha –1 ; amount superior to results found in studies made on the endemic environment of beavers. In relation to wood volume, over half of the stocks of N. pumilio forests associated to water resources have been lost in Tierra del Fuego due to the effect of beaver. The most important volume loss of this species derives from the death of individuals in flooded zones as a result of dike construction.
Julio Escobar - One of the best experts on this subject based on the ideXlab platform.
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First test for eradication of beavers (Castor Canadensis) in Tierra del Fuego, Argentina
Biological Invasions, 2020Co-Authors: Pablo Jusim, Julio Escobar, Andrea P. Goijman, María Luisa Carranza, Adrián SchiaviniAbstract:The North American beaver ( Castor Canadensis ) was introduced in 1946 from Canada to Isla Grande de Tierra del Fuego to develop a fur industry. Their expansion to most of the habitats of Tierra del Fuego and their presence on the continent, moved Argentina and Chile to test their eradication. The objective of this paper is to analyse a pilot eradication test and determine which variables are associated with the capture success of beavers in a small area of the Fuegian forest. The pilot was conducted in the Corazón de la Isla reserve, Tierra del Fuego, Argentina, during April and May 2014, by three groups of trappers, using body-grip traps and snares. The capture success was modelled with different variables. A total of 115 individuals were captured after 590 and 265 body-grip and snare trapping-nights, respectively, with an overall efficiency of 13.5%. Using body-grip traps and placing traps in slides or burrows would increase trapping efficiency. This experience allowed us to evaluate techniques and generate recommendations for future beaver eradication trials on a larger scale: (a) the need to improve the data collection system through digital technology and georeferencing the location of operations, (b) the importance of the type of trap used according to the specific sites of the colony, (c) test alternative trapping strategies to reduce the eventual “learning” of animals, (d) drive the paradigm of hunters from yield oriented to eradication objectives and (e) ensure the political sustainability of the wider program.
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understorey succession in nothofagus forests in tierra del fuego argentina affected by Castor Canadensis
Applied Vegetation Science, 2006Co-Authors: Guillermo Martinez Pastur, Vanessa M Lencinas, Julio Escobar, Paula Quiroga, Laura Margarita Elvira Malmierca, Marta Susana LizarraldeAbstract:Question: Does understorey richness, cover and biomass change during succession in abandoned Castor Canadensis impoundments of riparian Nothofagus forests? Location: Magellanic Nothofagus forests at Tierra del Fuego National Park (54°50'32.4'' S, 68°32'11.5'' W), Argentina. Methods: Five meadows of different time since abandonment (1, 5, 6, 9 and 20 years ago) and two controls (pure N. pumilio and mixed N. pumilio - N. betuloides forests) were sampled. Understorey variables (species richness, cover and biomass) in beaver meadows were measured at eight plots, as well as sapling and seedlings age and height. In control treatments, ten plots on each forest type characterized forest structure. Results: Beavers alter vegetation dynamics, modifying biomass and composition of the original forest communities. Richness, cover and biomass were significantly modified when compared to the original understorey. Ferns are the most affected group, while grasses became more abundant. Many species established in the impacted sectors, which did not grow in primary forests. Trees did not regenerate in impacted areas for long periods, and many understorey original species are missing. Nothofagus forests are not adapted to support a long-term beaver impact. Conclusions: Beavers modify the original ecosystem from closed forest to a grass- and sedge-dominated meadow, due to the lack of adaptive regeneration strategies in the Nothofagus forests. The maintenance of the present level of the beaver population is not sustainable over time, due to utilized and impacted tree biomass which could not be replaced by the natural dynamics of the forest ecosystem.