Diet of the reintroduced guanaco (Lama guanicoe) population into the Quebrada del Condorito National Park, Argentina

La reintroducción de especies silvestres es una herramienta recomendada cuando favorece la funcionalidad del ecosistema y se realiza en un proceso a largo plazo. Por ello es necesario evaluar científicamente los distintos aspectos ecológicos involucrados en el proceso de reintroducción. En el caso de los grandes herbívoros silvestres un aspecto importante es conocer los hábitos de forrajeo. En el presente estudio se determinó la dieta a nivel de especie de la población de guanacos (Lama guanicoe) reintroducida en el Parque Nacional Quebrada del Condorito (Córdoba, Argentina). Para ello entre febrero y agosto de 2009 se recolectaron muestras de heces frescas en del territorio ocupado por los grupos reproductivos dentro del Parque. La composición botánica de las muestras se determinó mediante análisis microhistológico. La dieta de los guanacos reintroducidos estuvo constituida principalmente por gramíneas y ciperáceas de bajo porte, características de los céspedes, y, a pesar de la alta diversidad de plantas vasculares presentes en el área de estudio, solo cinco especies representaron entre el 71 % (para los meses fríos y secos) y el 93 % (para los meses cálidos y húmedos) de la dieta consumida durante el período de estudio: Sorghastrum pellitum, Chascolytrum subaristatum, Carex fuscula, Eleocharis pseudoalbibracteata y Lachemilla pinnata. Asimismo, las cuatro primeras especies fueron consumidas en una proporción significativamente mayor a la abundancia en el campo, lo que estaría indicando que los guanacos reintroducidos se comportaron como consumidores selectivos. Por otra parte se detectó una variación estacional pequeña pero consistente en el consumo de las especies vegetales, incrementándose en los meses fríos y secos el consumo de las gramíneas de alto porte D. hieronymi y P. stuckertii, dominantes en los pajonales, y de especies leñosas. Esto se debe probablemente a la disminución de la productividad durante los meses fríos y secos en el área de estudio.Wild species reintroduction is a highly recommended tool when favors ecosystem functionality. It constitutes a long-term process and requires the evaluation of the different ecological aspects involved in the reintroduction process. In the case of large wild herbivores one important aspect that should be known is foraging habits. In the present study, diet at the species level was determined for the guanaco (Lama guanicoe) population reintroduced in the Quebrada del Condorito National Park (Córdoba, Argentina). Fresh faeces samples were collected within the territory occupied by reproductive groups in the Park, between February and August 2009. Diet botanic composition was determined by microhistological analysis. The diet of reintroduced guanacos was composed mainly by short grasses and sedges, characteristic plants of grazing lawns. Despite the high plant diversity in the study area, only five species represented 71% (for the cold and dry months) to 93% (for the warm and wet months) of the diet consumed during the study period in the Park: Sorghastrum pellitum, Chascolytrum subaristatum, Carex fuscula, Eleocharis pseudoalbibracteata y Lachemilla pinnata. The former four species were consumed in a proportion significantly higher than their abundance in the field, which is indicating that the reintroduced guanacos are behaving as selective consumers. Additionally, a small but consistent seasonal difference was detected in plant species consumption, with higher consumption of the tussock grasses D. hieronymi and P. stuckertii, dominant in tussock grasslands, and of woody plants, during the dry and cold season. Probably this was caused by the productivity decrease during cold and dry season months in the study area.Fil: Barri, Fernando Rafael. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Centro de Ecología y Recursos Naturales Renovables; Argentina. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Cordoba. Instituto de Diversidad y Ecologia Animal; ArgentinaFil: Falczuk, Valeria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto Multidisciplinario de Biología Vegetal (p); ArgentinaFil: Cingolani, Ana María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto Multidisciplinario de Biología Vegetal (p); Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; ArgentinaFil: Diaz, Sandra Myrna. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto Multidisciplinario de Biología Vegetal (p); Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentin

Foliar resistance to simulated extreme temperature events in contrasting plant functional and chorological types

We analysed leaf resistance of 41 Angiosperms belonging to a wide range of plant functional (PFTs) and chorological types (PCTs) to simulated frost and high-temperature extreme events (EE). Leaf resistance was estimated as percentage of membrane electrolyte leakage under heating and freezing treatments in the lab. Leaf resistance to heating or freezing was not significantly correlated with the main resource-use characteristics that defined PFTs, such as leaf specific area, toughness, N concentration or thickness. Leaf resistance to heating differed among PFTs (graminoids and bromeliads were the more resistant groups), but not among PCTs. In contrast, leaf resistance to freezing significantly differed among PCTs. Along a steep regional climatic gradient, climate variables (annual mean temperature, mean minimum temperature, mean maximum temperature and number of frost-free months) at the locations where the given species were most abundant were also significantly correlated with freezing resistance. Species from colder habitats both at the sub-continental and regional scales showed the highest leaf resistance to freezing. Our work indicates that leaf resistance to climatic EE and resource-use strategy (assessed in previous studies) represent two different, partially decoupled axes of plant specialisation. It also suggests that changes in the frequency of very low temperature events might have regional-scale impacts on vegetation, whereas changes in the frequency of very high temperature events might have more influence at the local scale.Fil: Gurvich, Diego Ezequiel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Díaz, Sandra Myrna. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Falczuk, Valeria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Pérez Harguindeguy, Natalia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Cabido, Marcelo Ruben. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Thorpe, P. Christopher. University of Sheffield; Reino Unid

Evidence of shift in C4 species range in central Argentina during the late Holocene.

Aim: Millennial-scale biogeographic changes are well understood in many parts of the world, but little is known about long-term vegetation dynamics in subtropical regions. Here we investigate shifts in C3/C4 plant abundance occurred in central Argentina during the past few millenniaMethods: We determined present day soil organic matter ??13C signatures of grasslands, shrublands and woodlands, containing different mixtures of C3 and C4 plants. We measured past changes in the relative cover of C3/C4 plants by comparing ??13C values in soil profiles with present day ??13C signatures. We analyzed 14C activity in soil depths that showed major changes in vegetation. Results: Present day relative cover of C3/C4 plants determines whole ecosystem ??13C signatures integrated as litter and superficial soil organic matter (R2 = 0. 78; p < 0. 01). Deeper soils show a consistent shift in ??13C, indicating a continuous replacement of C4 by C3 plants since 3,870 (??210) YBP. During this period, the relative abundance of C3 plants increased 32% (average across sites) with significant changes being observed in all studied ecosystems. Conclusions: Our results show that C4 species were more abundant in the past, but C3 species became dominant during the late Holocene. We identified increases in the relative C3/C4 cover in grasslands, shrublands and woodlands, suggesting a physiological basis for changes in vegetation. The replacement of C4 by C3 plants coincided with changes in climate towards colder and wetter conditions and could represent a climatically driven shift in the C4 species optimum range.Fil: Silva, Lucas C. R.. University of Guelph. Global Ecological Change Laboratory. School of Environmental Sciences; CanadáFil: Giorgis, Melisa Adriana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto Multidisciplinario de Biología Vegetal (p); Argentina. Universidad Nacional de Córdoba; ArgentinaFil: Anand, Madhur. University of Guelph. Global Ecological Change Laboratory. School of Environmental Sciences; CanadáFil: Enrico, Lucas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto Multidisciplinario de Biología Vegetal (p); Argentina. Universidad Nacional de Córdoba; ArgentinaFil: Perez Harguindeguy, Natalia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto Multidisciplinario de Biología Vegetal (p); Argentina. Universidad Nacional de Córdoba; ArgentinaFil: Falczuk, Valeria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto Multidisciplinario de Biología Vegetal (p); Argentina. Universidad Nacional de Córdoba; ArgentinaFil: Tieszen, Larry L.. US Geological Survey Earth Resources Observation and Science (EROS) Center; Estados UnidosFil: Cabido, Marcelo Ruben. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto Multidisciplinario de Biología Vegetal (p); Argentina. Universidad Nacional de Córdoba; Argentin

Plant responses to grazing: A global synthesis.

Herbivory by domestic and wild ungulates is a major driver of global vegetation dynamics. However, grazing is not considered in dynamic global vegetation models, or more generally in studies of the effects of environmental change on ecosystems at regional to global scale. An obstacle to this is a lack of empirical tests of several hypotheses linking plant traits with grazing. We, therefore, set out to test whether some widely recognized trait responses to grazing are consistent at the global level. We conducted a meta-analysis of plant trait responses to grazing, based on 197 studies from all major regions of the world, and using six major conceptual models of trait response to grazing as a framework. Data were available for seven plant traits: life history, canopy height, habit, architecture, growth form (forb, graminoid, herbaceous legume, woody), palatability, and geographic origin. Covariates were precipitation and evolutionary history of herbivory. Overall, grazing favoured annual over perennial plants, short plants over tall plants, prostrate over erect plants, and stoloniferous and rosette architecture over tussock architecture. There was no consistent effect of grazing on growth form. Some response patterns were modified by particular combinations of precipitation and history of herbivory. Climatic and historical contexts are therefore essential for understanding plant trait responses to grazing. Our study identifies some key traits to be incorporated into plant functional classifications for the explicit consideration of grazing into global vegetation models used in global change research. Importantly, our results suggest that plant functional type classifications and response rules need to be specific to regions with different climate and herbivory history.Fil: Díaz, Sandra Myrna. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Lavorel, Sandra. Universite Joseph Fourier; FranciaFil: McIntayre, Sue. CSIRO Sustainable Ecosystems; Nueva ZelandaFil: Falczuk, Valeria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Casanoves, Fernando. Universidad Nacional de Córdoba. Facultad de Ciencias Agropecuarias; ArgentinaFil: Milchunas, Daniel G.. CSIRO Sustainable Ecosystems; Nueva Zelanda. State University of Colorado - Fort Collins; Estados UnidosFil: Skarpe, Christina. Norwegian Institute for Nature Research; NoruegaFil: Rusch, Graciela. Norwegian Institute for Nature Research; NoruegaFil: Sternberg, Marcelo. CSIRO Sustainable Ecosystems; Nueva Zelanda. Tel Aviv University; IsraelFil: Noy-meir, Imanuel. The Hebrew University of Jerusalem; IsraelFil: Landsberg, Jill. CSIRO Sustainable Ecosystems; Nueva ZelandaFil: Zhang, Wei. University of British Columbia; CanadáFil: Clark, Harry. Grasslands Research Centre; Nueva ZelandaFil: Campbell, Bruce D.. Hort Research Mt Albert; Nueva Zeland

The global spectrum of plant form and function: enhanced species-level trait dataset.

Here we provide the 'Global Spectrum of Plant Form and Function Dataset', containing species mean values for six vascular plant traits. Together, these traits -plant height, stem specific density, leaf area, leaf mass per area, leaf nitrogen content per dry mass, and diaspore (seed or spore) mass - define the primary axes of variation in plant form and function. The dataset is based on ca. 1 million trait records received via the TRY database (representing ca. 2,500 original publications) and additional unpublished data. It provides 92,159 species mean values for the six traits, covering 46,047 species. The data are complemented by higher-level taxonomic classification and six categorical traits (woodiness, growth form, succulence, adaptation to terrestrial or aquatic habitats, nutrition type and leaf type). Data quality management is based on a probabilistic approach combined with comprehensive validation against expert knowledge and external information. Intense data acquisition and thorough quality control produced the largest and, to our knowledge, most accurate compilation of empirically observed vascular plant species mean traits to date

The global spectrum of plant form and function: enhanced species-level trait dataset.

Here we provide the 'Global Spectrum of Plant Form and Function Dataset', containing species mean values for six vascular plant traits. Together, these traits -plant height, stem specific density, leaf area, leaf mass per area, leaf nitrogen content per dry mass, and diaspore (seed or spore) mass - define the primary axes of variation in plant form and function. The dataset is based on ca. 1 million trait records received via the TRY database (representing ca. 2,500 original publications) and additional unpublished data. It provides 92,159 species mean values for the six traits, covering 46,047 species. The data are complemented by higher-level taxonomic classification and six categorical traits (woodiness, growth form, succulence, adaptation to terrestrial or aquatic habitats, nutrition type and leaf type). Data quality management is based on a probabilistic approach combined with comprehensive validation against expert knowledge and external information. Intense data acquisition and thorough quality control produced the largest and, to our knowledge, most accurate compilation of empirically observed vascular plant species mean traits to date