Modern and late quaternary palynological analysis in the campos region (Uruguay and Southern Brazil): status of investigations, difficulties and potentialities

Los campos constituyen una de las regiones de los pastizales del Río de la Plata que se extiende en Uruguay y en la porción meridional de Rio Grande do Sul (Brasil), cuya potencialidad para realizar estudios palinológicos aún está escasamente explorada. En este trabajo se revisa y analiza el estado actual de las investigaciones palinológicas actuales y fósiles en la región de los campos. Se discuten los modelos de la relación polen-vegetación actual como análogo moderno y se sintetiza la información proveniente de los registros polínicos fósiles. La integración de estos resultados y la utilización de los modelos actuales para interpretar las secuencias fósiles permitieron realizar una reconstrucción preliminar de la historia de la vegetación de la región de los campos durante el Pleistoceno Tardío y Holoceno. Los cambios de lavegetación fueron relacionados con forzantes abióticos (cambios en el nivel relativo del mar o en las condiciones climáticas) y bióticos (antrópicos),y se postulan posibles rutas de migración de distintos taxones y vinculaciones de los campos con otras regiones fitogeográficas. Finalmente se discuten las potencialidades de la región de los campos para los estudios palinológicos, las dificultades que frecuentemente se presentan para la integración de la información y se puntualizan aquellos aspectos que podrían considerarse en futuros trabajos para realizar interpretaciones más ajustadas de la información paleoecológica disponible.Fil: Mourelle Civano, Dominique. Universidad de la República. Facultad de Ciencias; UruguayFil: Macedo, Renato. Universidade Federal do Rio Grande do Sul; BrasilFil: Prieto, Aldo Raul. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentin

Floristic composition of Isla de las Gaviotas, Río de la Plata estuary, Uruguay

Isla de las Gaviotas is an island located in Río de la Plata estuary, Uruguay. The aim of this study is to determine and analyze plant species composition on this island and to identify vegetation zonation patterns. An angiosperm species list was generated using a qualitative sampling technique. We registered a total of 27 species, distributed among 18 families. According to species distribution patterns on the island, we propose four vegetation zones: North, Central, Southeast and West. Exotic species comprised 52% of the total number of species, reflecting a history of disturbance in the area. Nonetheless, this site also has a remarkable number of native species, in particular Heliotropium curassavicum, which is listed among Uruguayan species of conservation concern. Given that the loss of coastal plant species is a current problem, the proportion of native halophyte species recorded (37%) indicated the island’s importance as a relict of Uruguayan coastal vegetation

Relación polen-vegetación actual en Uruguay

Tribunal: Dr. Mauricio Bonifacino, Dra. Lina Bettucci, Dra. Silvina StutzOrientador: Dr. Aldo Priet

Pollen and spores from surface samples in the campos region of Uruguay and their paleoecological implications

ABSTRACT In this study we describe and illustrate pollen and spores that have been identified as significant in modern and fossil samples from the campos region of Uruguay. We provide new information about modern pollen assemblages and their relationship to the vegetation types of this region. We discuss the taxonomic limitations of pollen and spores and their representation in both modern and fossil samples. We highlight the importance of identifying both silent and key indicator taxa for making accurate paleoecological interpretations. We also emphasize the importance of knowing the pollination strategies of parental plants because many of them are zoophilous, and so small changes in the proportions of their pollen grains in fossil assemblages could reflect important changes in vegetation. This study presents a practical approach to paleoecological research, which not only produces robust results in studies of the campos region, but can be applied to other grassland ecosystems, including those in temperate regions

Modern pollen assemblages of surface samples and their relationships to vegetation in the campos region of Uruguay

This study documents the relationship between the modern pollen assemblages and the main vegetation types of the campos region of Uruguay. A total of 46 surface soil samples from grasslands, riparian forests, low mountain shrublands-forests, psammophilous forests and "Candela" coastal shrublands were studied. Cluster Analysis and Detrended Correspondence Analysis, performed on 23 selected pollen taxa, revealed five distinct pollen assemblages which correlate well with each vegetation type. Grasslands are characterized by Poaceae, Asteraceae subf. Asteroideae, Cyperaceae and Apiaceae. The limited taxonomic resolution of their main pollen grains did not make it possible to classify the grasslands in more detail. Riparian forests are characterized by exclusive hydrophilous trees, aquatic herbs and high values of Myrtaceae. Comparison of modern pollen and vegetation revealed that some important floristic elements from riparian forests were completely absent from the pollen assemblages or appeared in very low percentages. Low mountain shrublands-forests are co-dominated by herbaceous (Poaceae and Cyperaceae) and arboreal (Lithraea/Schinus and Myrtaceae) pollen, together with Asteraceae subf. Asteroideae. Psammophilous forests are also characterized by the co-dominance of herbaceous and arboreal pollen, but with higher values of Ephedra tweediana and Rhamnaceae, and minor of Asteraceae subf. Asteroideae. "Candela" coastal shrublands are characterized by maximum values of Dodonaea viscosa. The samples ordination in DCA on the first axis suggests a gradient related to the substrate water availability, reflecting major availability in riparian forests and minor availability in grasslands. Samples progressively separated along the second axis probably reflect the substrate-type and topography. Grasslands pollen assemblages, dominated by anemophilous pollen, represent the regional vegetation of the campos region. However, grasslands are masked in local forests and shrublands samples, where the zoophilous pollen of their characteristic species dominates, representing each local vegetation type. This pollen dataset completes the information available for the Río de la Plata grasslands, useful for the interpretation of the region's fossil pollen records and for similar environments in different geographical areas. © 2012 Elsevier B.V.Fil: Mourelle Civano, Dominique. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biología. Laboratorio de Paleoecología y Palinologia; ArgentinaFil: Prieto, Aldo Raul. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biología. Laboratorio de Paleoecología y Palinologia; Argentin

A synthesis of palynological data from the Lower Permian Cerro Pelado Formation (Paraná Basin, Uruguay): A record of warmer climate stages during Gondwana glaciations

This paper presents a synthesis of the palynological record in the Cerro Pelado Formation deposits (Lower Permian, Paraná basin, Cerro Largo Department, north eastern Uruguay) based on pre-existing data and new findings. The successions studied in this formation consist mainly of non-marine to glacial-marine mudstones and sandy mudstones. The palynological assemblages yielded by 32 samples collected from two outcrops and thirty borehole samples demonstrate that not significant floral changes took place through the considered stratigraphic range. The correlation of these assemblages with biostratigraphic palynozones, proposed previously for the Paraná/ Chacoparaná Basin of Brazil, Argentina and Uruguay point to their Early Permian age. The most widespread spore genera in these assemblages are Punctatisporites, Lundbladispora, Vallatisporites and Granulatisporites. Among pollen grains, Caheniasaccites, Vittatina, Potonieisporites, Protohaploxypinus and Plicatipollenites are the most representative. Palynomorphs assigned to Chlorophyta, Prasinophyta, and acritarchs indicate the development of brackish to fresh water lacustrine environments. The results from the facies and palynological analyses suggest that these deposits were formed during interglacial or postglacial warmer climatic episodes. This fact would agree well with the proposal that Gondwana glaciations were characterized by discrete glacial phases (with multiple glacial lobe advance-retreat phases) alternating with warmer climatic episodes. These episodes could be recognized thanks to sub-glacial and melt water related continental deposits that would bear characteristic palynological assemblages, like the recorded in the Cerro Pelado Fm. successions

Riparian woody vegetation history in the campos region, southeastern South America, during two time windows: late Pleistocene and late Holocene

A detailed palynological record from Laguna Formosa (northeastern campos region, 31°S; 54°W) documents the dynamic balance between grasslands and riparian forests during the late Pleistocene (14,570 to 13,500 cal yr BP) and late Holocene (3280 cal yr BP to the present). Modern pollen-vegetation relationships and the woody pollen dispersal capacity analyses were used to improve the vegetation reconstruction. Grasslands were regionally dominant throughout the record. However, at 14,570 cal yr BP hydrophilous taxa reflect the development of riparian hydrophilous shrublands along freshwater bodies, promoting the fixation of the riverbanks, maintaining shallow, calm and clear water conditions under a relatively wet and not so cool climate. This is the first evidence of woody riparian vegetation development along freshwater bodies for the lowlands of the northern campos during the late glacial period. At 3280 cal yr BP riparian forests consisted of both hydrophilous and mesophilous woody taxa. Since 2270 cal yr BP woody vegetation gradually increased, accompanied by the incorporation of other taxa by 940 cal yr BP, and achieving a composition similar to that of the contemporary time at ca. 540 cal yr BP. The increased woody vegetation since ca. 2270 cal yr BP, and the more frequent and intense flooding events between 1800 and 1200 cal yr BP, could be related to higher precipitation over La Plata Drainage Basin, related with the high ENSO amplitude. In addition, pollen from taxa that currently no longer develops in the study area suggests connections between southern Brazil and Uruguay, and between the campos and the Chaco phytogeographic province.Fil: Mourelle Civano, Dominique. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Centro Universitario Regional Este; UruguayFil: Prieto, Aldo Raul. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Garcia Rodriguez, Felipe. Centro Universitario Regional Este; Urugua

Vegetation changes of laguna merín basin, Uruguay, during the last CA. 2000 CAL. YR BP

A análise palinológica de uma sequência extraída de um banhado de água doce na localidade Paso BarrancaIndia Muerta da bacia da Lagoa Mirim (sequência RB1, 33°40’36“S-53°49’15”O), sudeste do Uruguai, permitiu reconstruir a história da vegetação durante os últimos ca. 2000 cal. anos AP. A relação entre o pólen e a vegetação atual na escala regional na bacia da Lagoa Mirim foi usada para interpretar a sequência fóssil RB1. Os resultados revelaram que durante o Holoceno tardio, os campos dominavam o Paso Barranca-India Muerta, acompanhados de matas ciliares, palmeiras e banhados de água doce, sugerindo uma vegetação diversa na área em condições úmidas ou em balanço hídrico positivo. No entanto, o banhado apresentou variações na profundidade e na extensão, provavelmente em resposta às mudanças locais no conteúdo de água no solo. A partir de ca. 2000 cal. anos AP, a disponibilidade de água foi variável, aumentando para ca. 700 cal. anos AP. Posteriormente, as condições mantiveram-se relativamente estáveis, até ca. 300 cal. anos AP, quando a quantidade de água do banhado aumentou progressivamente até atingir as condições atuais. Estas alterações locais na disponibilidade de água no solo poderiam responder à variabilidade climática do sudeste uruguaio no Holoceno tardio, mesmo sob condições climáticas úmidas, inferidas para toda a região dos campos das formações campestres da região do Río de la Plata. As mudanças na vegetação inferidas pelo registro palinológico não foram relacionadas com as alterações antrópicas realizadas pelas populações pré-hispânicas da região. Este trabalho melhora substancialmente o nosso conhecimento da vegetação e as condições climáticas do Holoceno tardio na bacia da Lagoa Mirim.The palynological analysis from a sedimentary sequence from the wetland Paso Barranca-India Muerta at Laguna Merín basin (RB1 core, 33°40´36"S - 53°49´15"W) of southeastern Uruguay, allowed to reconstruct the vegetation history during the last ca. 2000 cal. yr BP. The modern pollen-vegetation relationship from Laguna Merín basin at regional scale was used for the interpretation of RB1 fossil record. Results revealed that during the late Holocene grassland vegetation dominated at Paso Barranca-India Muerta, together with the development of riparian forests, palm grooves and freshwater marshes. This suggests a diverse vegetation on the area under either humid climatic conditions or a positive water balance. However, the freshwater marsh showed fluctuations in depth and extent, probably as a response to local soil water content changes. Since ca. 2000 cal. yr BP the marsh water level was variable, increasing at ca. 700 cal. yr BP. Thereafter, conditions remained relatively steady until ca. 300 cal. yr BP, when the marsh water level progressively increased until reaching the current conditions. The local soil water content changes would have responded to the late Holocene climate variability suggested for southeastern Uruguay, even under humid conditions proposed for the campos region of the Río de la Plata grasslands. The vegetation changes inferred from the palynological analysis could not be related to the anthropogenic changes introduced by the pre-Hispanic populations in the region. This work substantially improves our knowledge of the late Holocene vegetation and climate conditions in the Laguna Merín basin.Fil: Mourelle Civano, Dominique. Universidad de la República. Facultad de Ciencias; Uruguay. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Prieto, Aldo Raul. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Garcia Rodriguez, Felipe. Universidad de la República. Facultad de Ciencias; Urugua

Plantas Vasculares: Estudio de la sistemática, evolución y morfo-ecología de las traqueofitas

Este libro es la guía teórica y práctica de la asignatura Plantas Vasculares que forma parte del plan de estudio de la Licenciatura de Ciencias Biológicas de la Facultad de Ciencias Exactas y Naturales, UNMDP. Esta cursada ofrece un panorama de las plantas vasculares agrupadas en categorías sistemáticas. Abarca tres grandes entidades vegetales conocidas como pteridofitas, gimnospermas y angiospermas. Estos tres grupos incluyen a la mayor parte de la flora del mundo. Se presta especial atención a los grupos con representantes en el país, ubicándolos en el contexto fitogeográfico argentino. También son incluidas las especies cultivadas, destacándose las de mayor valor económico.Fil: Mancini, Maria Virginia. No especifíca;Fil: Mourelle Civano, Dominique. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Sottile, Gonzalo David. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Thevenon, Mario Alberto. No especifíca