50 research outputs found
Habitat-specific vegetation and seasonal drivers of bird community structure and function in southern Patagonian forests
Biodiversity conservation requires knowledge about the factors that influence the structure and function of biotic assemblages. In southern Patagonian Nothofagus forests, birds are the most abundant and diverse vertebrates and are known to have different requirements for nesting, breeding and feeding. Therefore, we chose this group to analyze key drivers of avian community dynamics; for conservation purposes, this information is requisite to manage Nothofagus forest landscapes and their associated biota. We first characterized forest structure and understory floristic composition in open and closed canopy broadleaved forests of mixed deciduous (MD) and mixed deciduous-evergreen (MDE) species on the southern coast of Tierra del Fuego National Park, Argentina. For each habitat, bird assemblages were assessed using point counts, checklists and mistnetting. We used ANOVAs and multivariate methods to analyze changes in bird species richness, density, and biomass as a function of habitat and seasonal characteristics. Forest structure and understory plant communities influenced avian assemblage and density; MDE forests had significantly greater species richness, but lower density than MD. Plus, particular species were associated with specific understory conditions, such as Anairetes parulus and Zonotrichia capensis whose presence was related to shrubs. Additionally, variations observed between seasons apparently were related to differential uses of each habitat type during certain times of year. Finally, it was not possible to define a single forest type with greater conservation value for birds; each had a specific bird species assemblage. Consequently, our results suggest the importance of a full representation of habitats to preserve the region’s bird diversity, which also has been described for forest invertebrates and understory plants
Variabilidad fenotípica de Berberis microphylla G. Forst. en poblaciones naturales de Tierra del Fuego, una especie frutal forestal no maderable con posibilidad de diversificar la producción agroforestal patagónica
Las especies nativas de la Patagonia como las del género Berberis L., llamadas «calafates» o «michay», han hecho una importante contribución a la alimentación y la salud de las culturas locales. En los últimos años, se ha incrementado la demanda de frutos de estos arbustos y en particular de B. microphylla, tanto para el consumo en fresco como para la elaboración de diversos productos como dulces y jaleas, pulpas para la elaboración de helados, bebidas sin alcohol, a su vez que se emplean en productos cosméticos.A esto debe sumarse el hecho que se ha incorporado al Código Alimentario Argentino por Resolución Conjunta 22/2006 y 409/2006. Estos hechos ponen de manifiesto la necesidad de estudiar la variabilidad fenotípica de esta especie en diferentes ambientes en donde crece naturalmente con el objetivo general de contribuir al conocimiento, la conservación, el mejoramiento y posterior uso sustentable de los recursos vegetales de la Patagonia para generar nuevas alternativas productivas para la región y a nivel internacional. Como objetivos específicos se propusierona) realizar una caracterización morfológica y bioquímica de flores y frutos, b) estudiar la fenología y eficiencia reproductiva y c) correlacionar todas las variables estudiadas para determinar la variabilidad fenotípica de B. microphylla intra e inter poblaciones en Tierra del Fuego y su relación con las condiciones ambientales. Se seleccionaron de 10 a 12 plantas adultas de B. microphylla que crecen naturalmente en 3 sitios con características ambientales diferentes en Tierra del Fuego, Argentina. Se ha encontrado plasticidad fenotípica en algunos caracteres morfológicosy bioquímicos de las flores y frutos entre poblaciones y plantas, a la vez que entre las estaciones de crecimiento analizadas. Además, se identificaron plantas con un comportamiento destacado para ser propagadas clonalmente y evaluadas ex situ para el inicio de un programa de mejoramiento
Diffraction In The Binary Encounter Electron Peak Observed In Collisions Of 0.6 MeV Amu⁻¹ I7+, I23+ And Au11+ Projectiles With He And Ar
Relative double differential cross sections for electron emission from collisions of 0.6 MeV amu-1I7+and I23+ projectiles with Ar and Au11+projectiles with He were measured for electron energies from 100 eV to 2000 eV and for angles from 0° to 50°. Experimentally observed sudden shifts of the position of the binary encounter peak were interpreted as resulting from quantum interference in the scattering of target electrons from the partially stripped projectile ion. To this end calculations for the elastic scattering of free electrons initially at rest in the laboratory reference frame from the screened projectile field as well as model calculations of binary encounter electron production taking into account the target Compton profile were performed and compared with the experimental results. Good agreement was obtained for the angular locations of these shifts as well as for the angular distribution of the binary encounter electron yield. © 1992 IOP Publishing Ltd
Exemplary Knowledge Transfer Between Germany and Patagonia as Contribution to the Regional Achievement of the UN Sustainable Development Goals 2030
Concerted efforts are required to achieve the UN Sustainable Development Goals (SDGs) of the 2030 Agenda. In our study, we intend to outline how valuable synergy effects can be obtained from bilateral cooperation between Germany and Patagonia in order to protect temperate forest ecosystems and to ensure long-term and sustainable use of terrestrial natural resources. The additional benefit of this transcontinental and transhemispherical cooperation is that there are analogies between the Northern and Southern hemispheres, but also distinct differences that complement each other perfectly. We show in an exemplary way, how the challenges of Global Warming and the associated increased vulnerability to forest fires and other natural risks can be tackled. Knowledge transfer and common strategies will provide sound solutions for SDG 13 (urgent action to combat climate change and its impacts), SDG 15 (sustainable use of terrestrial ecosystems, sustainably managed forests, combating desertification, and halting and reversing land degradation and halting biodiversity loss) and SDG 17 (strengthening the means of implementation and revitalizing the global partnership for sustainable development).Fil: Walentowski, H.. University of Applied Sciences and Arts; AlemaniaFil: Hohnwald, S.. University of Applied Sciences and Arts; AlemaniaFil: Thren, M.. University of Applied Sciences and Arts; AlemaniaFil: Kappas, M.. Universität Göttingen; AlemaniaFil: Leuschner, C.. Universität Göttingen; AlemaniaFil: Lencinas, José Daniel. Centro de Investigación y Extensión Forestal Andino Patagónico; Argentina. Centro de Investigación y Extensión Forestal Andino Patagónico; ArgentinaFil: Bava, J.. Centro de Investigación y Extensión Forestal Andino Patagónico; ArgentinaFil: Loguercio, Gabriel Angel. Centro de Investigación y Extensión Forestal Andino Patagónico; Argentina. Centro de Investigación y Extensión Forestal Andino Patagónico; ArgentinaFil: Urretavizcaya, María Florencia. Centro de Investigación y Extensión Forestal Andino Patagónico; Argentina. Centro de Investigación y Extensión Forestal Andino Patagónico; ArgentinaFil: Barrotaeveña, C.. Centro de Investigación y Extensión Forestal Andino Patagónico; ArgentinaFil: Martínez Pastur, Guillermo José. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Zerbe, S.. Free University of Bozen ; Itali
Compositional shifts of alpine plant communities across the high Andes.
Aim: Climate change is transforming mountain summit plant communities worldwide, but we know little about such changes in the High Andes. Understanding large-scale patterns of vegetation changes across the Andes, and the factors driving these changes,
is fundamental to predicting the effects of global warming. We assessed trends in vegetation cover, species richness (SR) and community-level thermal niches (CTN) and tested whether they are explained by summits' climatic conditions and soil temperature trends. Location: High Andes. Time period: Between 2011/2012 and 2017/2019. Major taxa studied: Vascular plants. Methods: Using permanent vegetation plots placed on 45 mountain summits and soil temperature loggers situated along a ~6800 km N-S gradient, we measured species and their relative percentage cover and estimated CTN in two surveys (intervals between 5 and 8 years). We then estimated the annual rate of changes for the three variables and used generalized linear models to assess their relationship with annual precipitation, the minimum air temperatures of each summit and rates of change in the locally recorded soil temperatures.
Results: Over time, there was an average loss of vegetation cover (mean = −0.26%/ yr), and a gain in SR across summits (mean = 0.38 species m2/yr), but most summits had significant increases in SR and vegetation cover. Changes in SR were positively related to minimum air temperature and soil temperature rate of change. Most plant communities experienced shifts in their composition by including greater abundances of species with broader thermal niches and higher optima. However, the measured changes in soil temperature did not explain the observed changes in CTN. Main conclusions: High Andean vegetation is changing in cover and SR and is shifting towards species with wider thermal niche breadths. The weak relationship with soil temperature trends could have resulted from the short study period that only marginally captures changes in vegetation through time.EEA Santa CruzFil: Cuesta, F. Universidad de las Américas. Grupo de Investigación en Biodiversidad Medio Ambiente y Salud – BIOMAS; Ecuador.Fil: Carilla, Julieta. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Carilla, Julieta. Universidad Nacional de Tucumán. Instituto de Ecología Regional; Argentina.Fil: Llambí, L.D. Universidad de Los Andes. Instituto de Ciencias Ambientales y Ecológicas; Venezuela.Fil: Llambí, L.D. Consorcio para el Desarrollo Sostenible de la Ecorregión Andina (CONDESAN); Perú.Fil: Muriel, P. Pontificia Universidad Católica del Ecuador. Escuela de Ciencias Biológicas Laboratorio de Ecofisiología; Ecuador.Fil: Lencinas, María Vanessa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas (CADIC); Argentina.Fil: Meneses, R. I. Universidad Católica del Norte. Instituto de Investigaciones Arqueológicas y Museo; Chile.Fil: Feeley, K. J. University of Miami. Biology Department. Coral Gables; Estados UnidosFil: Pauli, H. Austrian Academy of Sciences. Institute for Interdisciplinary Mountain Research; Austria.Fil: Pauli, H. University of Natural Resources and Life Sciences. Department of Integrative Biology and Biodiversity Research; Austria.Fil: Aguirre, N. Universidad Nacional de Loja. Carrera de Ingeniería Forestal. Centro de Investigaciones Tropicales del Ambiente y Biodiversidad (CITAB); Ecuador.Fil: Beck, S. Museo Nacional de Historia Natural - Instituto de Ecología (UMSA). Herbario Nacional de Bolivia; Bolivia.Fil: Peri, Pablo Luis. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Santa Cruz; Argentina.Fil: Peri, Pablo Luis. Universidad Nacional de la Patagonia Austral; Argentina.Fil: Peri, Pablo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Tovar, C. Royal Botanical Gardens Kew. Jodrell Laboratory; Reino Unid
Diversidad de plantas vasculares en bosques continuos y relictuales de Nothofagus antárctica (Nothofagaceae) en Patagonia austral
La historia de los bosques de Nothofagus antarctica (ñire, ñirre) está asociada a profundos disturbios geológicos y climáticos. A éstos se le suman los disturbios más recientes, que junto a los usos culturales de la tierra contribuyen a la fragmentación del hábitat. En el ecotono bosque- estepa, N. antarctica forma bosquetes insertos en una matriz de estepa llamados relictos. Éstos se encuentran separados de los bosques andinos que forman una masa boscosa continua. Con el fin de estudiar los patrones de diversidad de plantas vasculares comparativamente entre bosques relictuales (R) y sus bosques continuos aledaños (A), se relevaron cinco localidades de Santa Cruz. Éstas se ubican en un amplio gradiente latitudinal (47° 4’- 51° 5’ LS) y experimentan diferentes historias de uso. Los componentes alfa y beta de la diversidad fueron relacionados a otras variables ambientales mediante un análisis multivariado de redundancia (RDA). Un total de 152 especies fue registrado. La diversidad alfa se evaluó mediante el índice Shannon-Wiener (H’) y no hubo diferencias significativas (p = 0,585) entre los ambientes A y R. Sin embargo, el índice H’ varió significativamente entre localidades (p <0,0001). Los mayores valores de H’ se registraron en la localidad ubicada en el extremo latitudinal Norte, mientras que los menores valores de H’ se registraron en la localidad ubicada en el extremo latitudinal Sur. El análisis de diversidad beta global (p sor) muestra más similitud entre los ambientes de las localidades ubicadas en los extremos Norte y Sur. Además, mientras que en la localidad más austral predomina el componente de diferenciación de especies por anidamiento (fnJ, en las otras localidades predomina el componente de recambio de especies (fsiJ. El RDA demuestra que existe una estrecha relación entre las características ambientales (suelo y el clima) y la composición de especies. Asimismo, muestra que la temperatura media es el principal factor que relaciona a las localidades de los extremos Norte y Sur; localidades de baja similitud entre sí (1 y 5). Mientras que el mayor contenido de nutrientes en el suelo se relaciona a las localidades intermedias (2, 3 y 4). Se concluye que el gradiente latitudinal tiene fuertes influencias en la diversidad de la comunidad del sotobosque de N. antarctica. Además, la intensidad del uso histórico de los bosques estaría relacionada a una mayor disminución en la riqueza de plantas vasculares de relictos, con respecto a los bosques continuos aledaños. Esto último denota una mayor sensibilidad de relictos a los disturbios antrópicos y la necesidad de implementar medidas adecuadas de conservación de los ambientes naturales.The history of Nothofagus antarctica forests in Santa Cruz is associated with significant geological and climatic disturbances. More recently, anthropic disturbances contributed to habitat fragmentation process. In the forest-steppe ecotone N. antarctica forms small forests inserted in a steppe matrix and separated from the Andean forests that are found towards the West forming continuous forest mass. Five localities of Santa Cruz were surveyed in order to study the patterns of diversity of vascular plants comparatively between relictual forests (R) and their surrounding continuous forests (A). The localities are located in a wide latitudinal gradient (47° 4’- 51° 5’ S) and experience different histories of use. The alpha and beta components of the diversity were linked to other environmental variables through a multivariate redundancy analysis (RDA). A total of 152 species were registered. The alpha diversity was evaluated using the Shannon-Wiener Index (H’). There was no significant differences (p = 0.585) between environments A and R. However, when comparing the sites the differences were significant (p <0.0001). The highest H values were recorded in the northern site, while the lowest H’ values occurred in southern site. The components analysis of global beta diversity (B ) showed lower values in the northern and southern extreme locations. In addition, while in the most austral site the component of species differentiation by nesting (Bnes) was more relevant, in the other evaluated sites the turnover component (Bsim) was predominant. The RDA shows that there is a close relationship between environmental characteristics (soil and climate) and species composition. It also shows that mean temperature is the main factor that relates localities of low similarity to each other (1 and 5). While the higher nutrient content in the soil is related to the intermediate localities (2, 3 and 4). We concluded that the latitudinal gradient had strong influences on the diversity of the understory community of N. antarctica forests. Furthermore, the intensity of the historical use of the forests can be related to a greater decrease in the vascular plant richness in relicts compared to the surrounding continuous forests. This denotes a greater sensitivity of relicts to anthropogenic disturbances and the need of an adequate conservation action.EEA Santa CruzFil: Vettese, Evangelina S. Consejo Nacional de Investigaciones Científicas y Técnicas. CIT Santa Cruz; ArgentinaFil: Orellana Ibáñez, Ivonne A. Universidad Nacional de la Patagonia San Juan Bosco. Facultad de Ciencias Naturales y Ciencias de la Salud; ArgentinaFil: Lencinas, María Vanessa. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Centro Austral de Investigaciones Cientificas; ArgentinaFil: Martínez Pastur, Guillermo José. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Centro Austral de Investigaciones Cientificas; ArgentinaFil: Peri, Pablo Luis. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Santa Cruz; Argentina. Universidad Nacional de la Patagonia Austral; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin
State Selective Scattering Angle Dependent Capture Cross Sections Measured by Cold Target Recoil Ion Momentum Spectroscopy
We have developed a new kind of recoil ion momentum spectroscopy technique, using a precooled supersonic gas jet target, to determine state selective, scattering angle dependent cross sections for swift ion-atom collisions ( 0. 25 , ..., , 1 MeV He2+ on He), by measuring the transverse and longitudinal momentum of the recoil ion. A longitudinal momentum resolution of ± 0.13 a. u. was achieved, about a factor of 30 better than ever obtained before, which enables a clear separation of K and L shell capture. In the transverse direction a resolution corresponding to a projectile scattering angle uncertainty of Δ ϑ P = ±1 μ rad was obtained
MASTREE+ : time-series of plant reproductive effort from six continents
Significant gaps remain in understanding the response of plant reproduction to environmental change. This is partly because measuring reproduction in long-lived plants requires direct observation over many years and such datasets have rarely been made publicly available. Here we introduce MASTREE+, a data set that collates reproductive time-series data from across the globe and makes these data freely available to the community. MASTREE+ includes 73,828 georeferenced observations of annual reproduction (e.g. seed and fruit counts) in perennial plant populations worldwide. These observations consist of 5971 population-level time-series from 974 species in 66 countries. The mean and median time-series length is 12.4 and 10 years respectively, and the data set includes 1122 series that extend over at least two decades (≥20 years of observations). For a subset of well-studied species, MASTREE+ includes extensive replication of time-series across geographical and climatic gradients. Here we describe the open-access data set, available as a.csv file, and we introduce an associated web-based app for data exploration. MASTREE+ will provide the basis for improved understanding of the response of long-lived plant reproduction to environmental change. Additionally, MASTREE+ will enable investigation of the ecology and evolution of reproductive strategies in perennial plants, and the role of plant reproduction as a driver of ecosystem dynamics
MASTREE+: Time-series of plant reproductive effort from six continents.
Significant gaps remain in understanding the response of plant reproduction to environmental change. This is partly because measuring reproduction in long-lived plants requires direct observation over many years and such datasets have rarely been made publicly available. Here we introduce MASTREE+, a data set that collates reproductive time-series data from across the globe and makes these data freely available to the community. MASTREE+ includes 73,828 georeferenced observations of annual reproduction (e.g. seed and fruit counts) in perennial plant populations worldwide. These observations consist of 5971 population-level time-series from 974 species in 66 countries. The mean and median time-series length is 12.4 and 10 years respectively, and the data set includes 1122 series that extend over at least two decades (≥20 years of observations). For a subset of well-studied species, MASTREE+ includes extensive replication of time-series across geographical and climatic gradients. Here we describe the open-access data set, available as a.csv file, and we introduce an associated web-based app for data exploration. MASTREE+ will provide the basis for improved understanding of the response of long-lived plant reproduction to environmental change. Additionally, MASTREE+ will enable investigation of the ecology and evolution of reproductive strategies in perennial plants, and the role of plant reproduction as a driver of ecosystem dynamics