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Díaz Rivas Plata, Eimy Tabatha - One of the best experts on this subject based on the ideXlab platform.
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Uso de líquenes como bioindicadores de presencia de metales pesados en áreas cercanas a empresas mineras de altura del Perú
Universidad Nacional de Ingeniería, 2006Co-Authors: Díaz Rivas Plata, Eimy TabathaAbstract:El presente trabajo de tesis demuestra la utilización de los líquenes como bioindicadores de contaminación por presencia de metales pesados en áreas andinas ubicadas en los alrededores de las unidades mineras. Por ser organismos simbiontes, se considera a los líquenes como bioindicadores por excelencia. El área de trabajo estudiada comprende dos áreas adyacentes, ubicadas en el distrito de Huay Huay, provincia de Yauli, Región Junín, entre 4700 - 4900 msnm, una de las cuales se encuentra aledaña a la Unidad Minera Andaychagua de “Volcan Compañía Minera” (sic). Se recolectó y determinó 41 especies de 14 familias, en su mayor parte líquenes crustosos, pretenecientes a la clase Lecanoromycetes, prevaleciendo Leprocaulon gracilis en el área minera y Xanthomendoza mendozae en el área de control. Treinta y cuatro de las 41 especies son nuevos registros para la colección de flora liquénica del Perú. El objetivo principal del estudio fue demostrar que el uso de bioindicadores para medir la contaminación ambiental brinda resultados más eficientes, ya que presentan ventajas comparativas con relación al monitoreo físico de metales pesados, principalmente por permitir el acceso a datos relativos a un organismo vivo. Se tomaron como referencia a los siguientes elementos: cobre, zinc, plomo, cadmio, plata, arsénico y manganeso. En una primera aproximación se logró identificar las especies de líquenes que pueden servir como principales bioindicadores. Los siguientes fueron los géneros y especies representativos en el área de control: Coccocarpia palmicola, Diploschistes scruposus, Lecanora garovaglii, Lecidea lithophila, Rhizocarpon obscuratum, Rh. petraeum, Rh. sublecanorinum, Rimelia sp, Tephromela atra, Umbilicaria calvescens y U. kraschenikowskii, mientras que los representativos del área minera fueron: Acarospora flava, Heterodermia sp y Leprocaulon gracilis. Lograda la primera aproximación, el estudio continuó con la determinación de la concentración de metales pesados de líquenes seleccionados y la determinación de la existencia de remoción de metales pesados en talos liquénicos al enjuagarlos con agua corriente (simulando la actividad de la lluvia), así como la determinación de la evidencia de remoción de metales pesados en agua contaminada al sumergir a los líquenes en ella, con el fin de utilizarlos como indicadores del nivel de contaminantes en el agua y como posibles agentes de "limpieza". La concentración de metales fue medida utilizando la espectrometría de masa con fuente acoplada de plasma inducida (ICP-MS), instalado en el laboratorio de análisis elemental del Field Museum de Chicago. El análisis estadístico de los experimentos de enriquecimiento y remoción de metales a través de agua, se realizó utilizando la prueba de Mann-Whitney y el análisis de distribución ecológica se realizó utilizando el análisis multidimensional de escala no paramétrica (NMS) y el índice de similitud o semejanza de Sørensen para establecer las diferencias a nivel de las comunidades liquénicas en las áreas analizadas. Los resultados muestran que definitivamente existe una carga de metales en el ambiente, específicamente en los cursos de agua aledaños a las zonas muestreadas. Del mismo modo, se demostró que los líquenes funcionan como bioacumuladores sumamente eficientes, especialmente los líquenes foliosos Xanthoparmelia sp y Paraparmelia sp. Finalmente, se probó que los líquenes no liberan los metales pesados que acumulan extracelularmente. En el Perú no se cuenta con reportes científicos completos al respecto, en consecuencia este trabajo contribuye en la provisión de información científica actual y debido a que nuestro país es eminentemente minero y nuestra geografía incluye regiones altoandinas, es posible replicar los experimentos y utilizar los datos obtenidos en beneficio de los pobladores.Tesi
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Uso de líquenes como bioindicadores de presencia de metales pesados en áreas cercanas a empresas mineras de altura en Perú
'Universidad Nacional de Ingenieria', 2006Co-Authors: Díaz Rivas Plata, Eimy TabathaAbstract:TesisEl presente trabajo de tesis demuestra la utilización de los líquenes como bioindicadores de contaminación por presencia de metales pesados en áreas andinas ubicadas en los alrededores de las unidades mineras. Por ser organismos simbiontes, se considera a los líquenes como bioindicadores por excelencia. El área de trabajo estudiada comprende dos áreas adyacentes, ubicadas en el distrito de Huay Huay, provincia de Yauli, Región Junín, entre 4700 - 4900 msnm, una de las cuales se encuentra aledaña a la Unidad Minera Andaychagua de “Volcan Compañía Minera” (sic). Se recolectó y determinó 41 especies de 14 familias, en su mayor parte líquenes crustosos, pretenecientes a la clase Lecanoromycetes, prevaleciendo Leprocaulon gracilis en el área minera y Xanthomendoza mendozae en el área de control. Treinta y cuatro de las 41 especies son nuevos registros para la colección de flora liquénica del Perú. El objetivo principal del estudio fue demostrar que el uso de bioindicadores para medir la contaminación ambiental brinda resultados más eficientes, ya que presentan ventajas comparativas con relación al monitoreo físico de metales pesados, principalmente por permitir el acceso a datos relativos a un organismo vivo. Se tomaron como referencia a los siguientes elementos: cobre, zinc, plomo, cadmio, plata, arsénico y manganeso. En una primera aproximación se logró identificar las especies de líquenes que pueden servir como principales bioindicadores. Los siguientes fueron los géneros y especies representativos en el área de control: Coccocarpia palmicola, Diploschistes scruposus, Lecanora garovaglii, Lecidea lithophila, Rhizocarpon obscuratum, Rh. petraeum, Rh. sublecanorinum, Rimelia sp, Tephromela atra, Umbilicaria calvescens y U. kraschenikowskii, mientras que los representativos del área minera fueron: Acarospora flava, Heterodermia sp y Leprocaulon gracilis. Lograda la primera aproximación, el estudio continuó con la determinación de la concentración de metales pesados de líquenes seleccionados y la determinación de la existencia de remoción de metales pesados en talos liquénicos al enjuagarlos con agua corriente (simulando la actividad de la lluvia), así como la determinación de la evidencia de remoción de metales pesados en agua contaminada al sumergir a los líquenes en ella, con el fin de utilizarlos como indicadores del nivel de contaminantes en el agua y como posibles agentes de "limpieza". La concentración de metales fue medida utilizando la espectrometría de masa con fuente acoplada de plasma inducida (ICP-MS), instalado en el laboratorio de análisis elemental del Field Museum de Chicago. El análisis estadístico de los experimentos de enriquecimiento y remoción de metales a través de agua, se realizó utilizando la prueba de Mann-Whitney y el análisis de distribución ecológica se realizó utilizando el análisis multidimensional de escala no paramétrica (NMS) y el índice de similitud o semejanza de Sørensen para establecer las diferencias a nivel de las comunidades liquénicas en las áreas analizadas. Los resultados muestran que definitivamente existe una carga de metales en el ambiente, específicamente en los cursos de agua aledaños a las zonas muestreadas. Del mismo modo, se demostró que los líquenes funcionan como bioacumuladores sumamente eficientes, especialmente los líquenes foliosos Xanthoparmelia sp y Paraparmelia sp. Finalmente, se probó que los líquenes no liberan los metales pesados que acumulan extracelularmente. En el Perú no se cuenta con reportes científicos completos al respecto, en consecuencia este trabajo contribuye en la provisión de información científica actual y debido a que nuestro país es eminentemente minero y nuestra geografía incluye regiones altoandinas, es posible replicar los experimentos y utilizar los datos obtenidos en beneficio de los pobladores
Roger Rosentreter - One of the best experts on this subject based on the ideXlab platform.
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biological soil crust diversity and composition in southwest idaho u s a
The Bryologist, 2019Co-Authors: Roger Rosentreter, Heather T RootAbstract:Biological soil crusts (BSCs) were sampled by habitat types within and adjacent to the Orchard Combat Training Center (OCTC) in southwest Idaho, U.S.A. Plots consisting of a 34.7 m radius circle, approximately equal to one acre or 0.38 hectares were sampled. We focused on five native vascular plant-dominated current habitat types within the OCTC, including: 1) Wyoming sagebrush, 2) saltbush, 3) rabbitbrush, 4) winterfat, and 5) Sandberg bluegrass. We describe how BSC cover and species richness varied with habitat types in the study area. We recorded the relative abundance of BSCs and vascular plant species and collected voucher specimens for each BSC. The biodiversity of each BSC in these arid habitat types was much greater than many ecologists have assumed. We found a total of 68 species of BSC across all 17 plots. BSC cover differed significantly across the different habitat types. BSC cover was significantly higher in sagebrush and saltbush as compared with Poa, rabbitbrush and winterfat habitat types. Overall, there was substantially more BSC richness (17–47 species) than vascular plant richness (4– 13 species), and BSC richness was positively related to vascular plant richness (R2=0.18, p=0.041). On average, each additional plant species was associated with 1.36 additional BSC species. BSC communities also varied across the habitat types with Buellia punctata as a significant indicator species for sagebrush, Toninia sedifolia for saltbush, and Cladonia pocillum for winterfat. Several BSC species were associated with 2 or 3 habitat types; for example, Cladonia fimbriata, Diploschistes muscorum, Leptogium lichenoides, Massalongia carnosa, Riccia sorocarpa and Trapeliopsis steppica were most common in the sagebrush, Poa, and rabbitbrush habitats. In contrast, Caloplaca tominii, Endocarpon loscosii, Placidium squamulosum and Psora tuckermanii were most common in winterfat and saltbush habitats.
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Bromus tectorum Litter Alters Photosynthetic Characteristics of Biological Soil Crusts from a Semiarid Shrubland
Soil Biology and Biochemistry, 2013Co-Authors: Marcelo D. Serpe, David J Eldridge, Eric Roberts, Roger RosentreterAbstract:Invasion by the exotic annual grass Bromus tectorum has increased the cover and connectivity of fine litter in the sagebrush steppes of western North America. This litter tends to cover biological soil crusts, which could affect their metabolism and growth. To investigate this possible phenomenon, biological soil crusts dominated by either the moss Bryum argenteum or the lichen Diploschistes muscorum were covered with B. tectorum litter (litter treatment) or left uncovered (control treatment) and exposed to natural field conditions. After periods of five and ten months, we removed the litter and compared the photosynthetic performance of biological soil crusts from the two treatments. Litter induced photosynthetic changes in our samples. In both B. argenteum and D. muscorum, biological soil crusts that had been covered with litter for ten months had lower rates of gross photosynthesis and lower chlorophyll content than control samples. Similarly in both biological soil crust types, litter reduced the rate of dark respiration. For D. muscorum, the reduction in dark respiration fully compensated for the decrease in gross photosynthesis, resulting in similar values of net photosynthesis in the two treatments. In contrast, for B. argenteum, net photosynthesis was four-times greater in the control than the litter treatment. Also under litter cover, D. muscorum showed three common adaptations to shade conditions: a decrease in the light compensation point, in the light intensity needed to achieve 95% of maximal net photosynthesis, and in the chlorophyll a/b ratio. None of these changes was apparent in B. argenteum. Overall, our results indicate that photosynthetic responses to the presence of litter varied among species of the crust biota and that the litter can reduce the photosynthetic capacity of biological soil crusts. These results help to explain field observations of decreases in biological soil crust cover and changes in biological soil crust composition with increases in litter cover, and suggest that the landscape-wide invasion by B. tectorum may have substantial effects on biological soil crust performance and therefore their capacity to function in semiarid shrublands.
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Seed water status and root tip characteristics of two annual grasses on lichen-dominated biological soil crusts
Plant and Soil, 2008Co-Authors: Marcelo D. Serpe, Shawna J. Zimmerman, Lynell Deines, Roger RosentreterAbstract:Biological soil crusts can affect seed germination and seedling establishment. We have investigated the effect of biological soil crusts on seed water status as a potential mechanism affecting seed germination. The seed water potential of two annual grasses, one exotic Bromus tectorum L. and another native Vulpia microstachys Nutt., were analyzed after placing the seeds on bare soil, on a crust that contains various lichens and mosses (mixed crust), or on a crust dominated by the crustose lichen Diploschistes muscorum (Scop.) R. Sant. ( Diploschistes crust). Seed water potential and germination were similar on the bare soil and the mixed crust, except for the initial germination of V. microstachys , which was higher on the mixed crust than on the bare soil. For the two grasses studied, seed water potential was significantly higher on the bare soil and mixed crust than on the Diploschistes crust. These differences in water potential correlated with differences in germination, which was much lower on the lichen crust. Experiments were conducted under two watering regimens. Increasing the frequency of watering amplified the differences in seed water potential and germination between the Diploschistes crust and the other two surfaces. For a particular watering regimen, the bare soil, mixed crust, and Diploschistes crust received the same amount of water, but they reached significantly different water potentials. Throughout the experiments, the water potential of the soil and mixed crust remained above −0.6 MPa, while there was a marked decline in the water potential of the Diploschistes surface to about −4 MPa. To ascertain that water was the major factor limiting germination on the Diploschistes crust, we conducted germination tests in an environment with 100% relative humidity. Under these conditions, germination on the Diploschistes crust was similar to that on the bare soil. However, the seeds that germinated on the Diploschistes crust did not penetrate this surface and approximately 60% of their root tips became necrotic. Our results indicate that the presence of D. muscorum can inhibit seedling establishment by two mechanisms: a reduction in seed water absorption and an increase in root tip mortality.
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Germination and seedling establishment of two annual grasses on lichen-dominated biological soil crusts
Plant and Soil, 2007Co-Authors: Lynell Deines, David J Eldridge, Roger Rosentreter, Marcelo D. SerpeAbstract:Biological soil crusts dominated by lichens are common components of shrub-steppe ecosystems in northwestern US. We conducted growth chamber experiments to investigate the effects of these crusts on seed germination and initial seedling establishment of two annual grasses; the highly invasive exotic Bromus tectorum L. and the native Vulpia microstachys Nutt. We recorded germination time courses on bare soil and two types of biological soil crusts; one composed predominantly of the lichen Diploschistes muscorum (Scop.) R. Sant. (lichen crust) and the other comprised of an assortment of lichens and mosses (mixed crust). Final germination on the lichen crust for both grass species was about a third of that on the bare soil surface. Mean germination time (MGT) was 3–4 days longer on the lichen crust compared with the bare soil. In contrast, there was no difference in germination percentage or MGT between the mixed crust and bare soil, and results were similar for both grass species. For both species, root penetration of germinating seeds on the lichen crust was lower than on the bare soil or mixed crust surfaces. The combined effects of the lichen crust on germination and root penetration resulted in an overall reduction in seedling establishment of 78% for V. microstachys and 85% for B. tectorum relative to the bare soil treatment. Our results clearly demonstrate that lichen-dominated biological soil crust can inhibit germination and root penetration, but the extent of these effects depends on the composition of the crust.
Fernández Brime Samantha - One of the best experts on this subject based on the ideXlab platform.
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Els líquens saxícoles i terrícoles del Parc Natural de Cap de Creus, amb un estudi filogenètic aplicat a la sistemàtica dels gèneres Diploschistes i Ingvariella
'Edicions de la Universitat de Barcelona', 2013Co-Authors: Fernández Brime SamanthaAbstract:[cat] Una de les línies de treball del Grup de Liquenologia del Departament de Biologia Vegetal (Unitat Botànica) de la Universitat de Barcelona ha tingut com a objectiu estudiar la diversitat dels líquens i fongs liquenícoles del territori català, així com la descripció de les comunitats liquèniques d’aquesta àrea. Malgrat la contribució d’aquests estudis al coneixement de la flora liquenològica de Catalunya, encara queden moltes àrees del territori que no s’han estudiat amb deteniment. Una d’aquestes àrees és la inclosa dins del Parc Natural de Cap de Creus, on els extensos afloraments de roques àcides estan ocupats, de forma parcial o total, per comunitats liquèniques. Vàrem endegar un estudi florístic que tenia com a objectius principals elaborar un catàleg dels líquens saxícoles i terrícoles del Parc, examinar les diferències morfològiques, anatòmiques o ecològiques dels tàxons estudiats respecte les dades bibliogràfiques per avaluar-ne la variabilitat i caracteritzar les preferències ecològiques de les espècies estudiades. Com a resultat d’aquest estudi, s’ha elaborat un catàleg florístic format per 263 espècies de líquens i 31 de fongs liquenícoles. Del total de tàxons citats, un és primera cita per Europa, vuit per la península Ibèrica i 34 per Catalunya. L’anàlisi fitogeogràfic determina que la flora liquènica està formada per tres grups de distribució principals: espècies mediterrànies, temperades-mediterrànies i d’àmplia distribució. Addicionalment, la flora es veu enriquida amb espècies de distribució atlàntica i de distribució centreuropea o àrtico-boreal. En el plantejament inicial d’aquesta tesi vam decidir incorporar un element addicional de caire més taxonòmic i filogenètic. Fent ús de les dades i espècimens recollits per al treball florístic, vam seleccionar aquells tàxons que resultessin conflictius i amb necessitat de ser revisats. Per aquest motiu, vam plantejar un examen exhaustiu centrat en els gèneres Diploschistes i Ingvariella. El gènere Diploschistes (Graphidaceae) presentava interessants qüestions no resoltes, com la delimitació del gènere, la validesa taxonòmica i sistemàtica dels tres grups d’espècies establerts en base a la morfologia dels apotecis, i la delimitació de diverses espècies. Per resoldre aquestes qüestions vam reconstruir diverses filogènies basades en caràcters emprats tradicionalment en taxonomia (morfològics, anatòmics, químics, ecològics), marcadors moleculars (nuITS, mtSSU i nu LSU) i la combinació d’ambdós tipus de caràcters. Els resultats confirmen que Diploschistes és monofilètic i demostren, per primera vegada, que els tres grups morfològics considerats dins del gènere són monofilètics, i se’n proposa una classificació infragenèrica. Les anàlisis filogenètiques revelen novetats en algunes espècies: l’existència d’un clade dins D. ocellatus, corresponent a espècimens sense apotecis que només tenen picnidis, i la presència d’un clade que agrupa tots els espècimens de la subespècie D. diacapsis subsp. neutrophilus, i que es proposa considerar al nivell de l’espècie. El gènere monotípic Ingvariella fou escindit de Diploschistes a partir de la morfologia de l’exciple, i mantingut dins de la família Thelotremataceae (= Graphidaceae) dins de l’ordre de les Ostropales. L’estudi detallat de la morfologia i anatomia d’Ingvariella ens va suggerir possibles afinitats amb altres famílies de l’ordre. Els objectius d’aquest estudi van ser avaluar la monofília d’Ingvariella i investigar la seva posició sistemàtica dins l’ordre. S’han inferit les relacions filogenètiques amb una matriu molecular (basada en els marcadors nuLSU i mtSSU), on s’ha inclòs una àmplia representació de membres de les Ostropales. Els resultats revelen que Ingvariella és monofilètic i pertany a la família de les Stictidaceae. Amb la inclusió del primer gènere de líquens saxícoles dins aquesta família, s’expandeix considerablement la diversitat ecològica de les Stictidaceae, dins les quals s’han inclòs fongs sapròfits, líquens corticícoles, i espècies que poden ésser facultativament liquenitzades. A més dels resultats esmentats, s’inclouen noves dades sobre les relacions entre altres famílies dins les Ostropales.[eng] This thesis is structured in two different parts. The first part, is an exhaustive floristic study of the saxicolous, epiphytic (only if sporadically growing on rocks), and terricolous lichens, and their lichenicolous fungi from the Cap de Creus Natural Park (NE Iberian Peninsula). The study reports 263 lichen taxa and 31 lichenicolous fungi from the study area, of which one is new for Europe, eight new for the Iberian Peninsula, and 34 for Catalonia. From a phytogeographical point of view, the flora is mainly composed of Mediterranean temperate species and Mediterranean lichens in a broad sense, enriched with a considerable number of Atlantic species in the most humid sites of the Park, and some species of boreal distribution. The large number of different microclimatic conditions in the area, combined with frequent extensions of rock outcrops, makes the Cap de Creus Natural Park an extraordinary region for the diversity of saxicolous and terricolous lichens. During the floristic study, we detected conflictive and unresolved taxonomic and systematic questions regarding the genera Diploschistes and Ingvariella. In the second part of the thesis, we have tried to clarify these questions within a phylogenetic framework. In the revision of Diploschistes, the reconstruction of the phylogenetic relationships of the genera within its family (Graphidaceae) confirmed that the genus is monophyletic. We also reconstructed the phylogenetic relationships within Diploschistes using a combined dataset of morphological, chemical, and molecular data. The results show that the three groups traditionally distinguished within the genus (based on ascomatal morphology) are monophyletic. Therefore, it is proposed a new subgeneric treatment for Diploschistes, and it is confirmed the taxonomical value of fruiting body types. In The monotypic genus Ingvariella was segregated from Diploschistes based on fruiting body anatomy, and placed within the Thelotremataceae (= Graphidaceae), in the order Ostropales. Our morphological observations, however, suggest affinities to other families within the order. We inferred the phylogenetic relationships of a broad array of ostropalean fungi based on mtSSU and nuLSU. The results demonstrate that Ingvariella is monophyletic and belongs to the Stictidaceae, expanding the broad ecological diversity of this family
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Els líquens saxícoles i terrícoles del Parc Natural de Cap de Creus, amb un estudi filogenètic aplicat a la sistemàtica dels gèneres Diploschistes i Ingvariella
'Edicions de la Universitat de Barcelona', 2012Co-Authors: Fernández Brime SamanthaAbstract:Una de les línies de treball del Grup de Liquenologia del Departament de Biologia Vegetal (Unitat Botànica) de la Universitat de Barcelona ha tingut com a objectiu estudiar la diversitat dels líquens i fongs liquenícoles del territori català, així com la descripció de les comunitats liquèniques d’aquesta àrea. Malgrat la contribució d’aquests estudis al coneixement de la flora liquenològica de Catalunya, encara queden moltes àrees del territori que no s’han estudiat amb deteniment. Una d’aquestes àrees és la inclosa dins del Parc Natural de Cap de Creus, on els extensos afloraments de roques àcides estan ocupats, de forma parcial o total, per comunitats liquèniques. Vàrem endegar un estudi florístic que tenia com a objectius principals elaborar un catàleg dels líquens saxícoles i terrícoles del Parc, examinar les diferències morfològiques, anatòmiques o ecològiques dels tàxons estudiats respecte les dades bibliogràfiques per avaluar-ne la variabilitat i caracteritzar les preferències ecològiques de les espècies estudiades. Com a resultat d’aquest estudi, s’ha elaborat un catàleg florístic format per 263 espècies de líquens i 31 de fongs liquenícoles. Del total de tàxons citats, un és primera cita per Europa, vuit per la península Ibèrica i 34 per Catalunya. L’anàlisi fitogeogràfic determina que la flora liquènica està formada per tres grups de distribució principals: espècies mediterrànies, temperades-mediterrànies i d’àmplia distribució. Addicionalment, la flora es veu enriquida amb espècies de distribució atlàntica i de distribució centreuropea o àrtico-boreal. En el plantejament inicial d’aquesta tesi vam decidir incorporar un element addicional de caire més taxonòmic i filogenètic. Fent ús de les dades i espècimens recollits per al treball florístic, vam seleccionar aquells tàxons que resultessin conflictius i amb necessitat de ser revisats. Per aquest motiu, vam plantejar un examen exhaustiu centrat en els gèneres Diploschistes i Ingvariella. El gènere Diploschistes (Graphidaceae) presentava interessants qüestions no resoltes, com la delimitació del gènere, la validesa taxonòmica i sistemàtica dels tres grups d’espècies establerts en base a la morfologia dels apotecis, i la delimitació de diverses espècies. Per resoldre aquestes qüestions vam reconstruir diverses filogènies basades en caràcters emprats tradicionalment en taxonomia (morfològics, anatòmics, químics, ecològics), marcadors moleculars (nuITS, mtSSU i nu LSU) i la combinació d’ambdós tipus de caràcters. Els resultats confirmen que Diploschistes és monofilètic i demostren, per primera vegada, que els tres grups morfològics considerats dins del gènere són monofilètics, i se’n proposa una classificació infragenèrica. Les anàlisis filogenètiques revelen novetats en algunes espècies: l’existència d’un clade dins D. ocellatus, corresponent a espècimens sense apotecis que només tenen picnidis, i la presència d’un clade que agrupa tots els espècimens de la subespècie D. diacapsis subsp. neutrophilus, i que es proposa considerar al nivell de l’espècie. El gènere monotípic Ingvariella fou escindit de Diploschistes a partir de la morfologia de l’exciple, i mantingut dins de la família Thelotremataceae (= Graphidaceae) dins de l’ordre de les Ostropales. L’estudi detallat de la morfologia i anatomia d’Ingvariella ens va suggerir possibles afinitats amb altres famílies de l’ordre. Els objectius d’aquest estudi van ser avaluar la monofília d’Ingvariella i investigar la seva posició sistemàtica dins l’ordre. S’han inferit les relacions filogenètiques amb una matriu molecular (basada en els marcadors nuLSU i mtSSU), on s’ha inclòs una àmplia representació de membres de les Ostropales. Els resultats revelen que Ingvariella és monofilètic i pertany a la família de les Stictidaceae. Amb la inclusió del primer gènere de líquens saxícoles dins aquesta família, s’expandeix considerablement la diversitat ecològica de les Stictidaceae, dins les quals s’han inclòs fongs sapròfits, líquens corticícoles, i espècies que poden ésser facultativament liquenitzades. A més dels resultats esmentats, s’inclouen noves dades sobre les relacions entre altres famílies dins les Ostropales.This thesis is structured in two different parts. The first part, is an exhaustive floristic study of the saxicolous, epiphytic (only if sporadically growing on rocks), and terricolous lichens, and their lichenicolous fungi from the Cap de Creus Natural Park (NE Iberian Peninsula). The study reports 263 lichen taxa and 31 lichenicolous fungi from the study area, of which one is new for Europe, eight new for the Iberian Peninsula, and 34 for Catalonia. From a phytogeographical point of view, the flora is mainly composed of Mediterranean temperate species and Mediterranean lichens in a broad sense, enriched with a considerable number of Atlantic species in the most humid sites of the Park, and some species of boreal distribution. The large number of different microclimatic conditions in the area, combined with frequent extensions of rock outcrops, makes the Cap de Creus Natural Park an extraordinary region for the diversity of saxicolous and terricolous lichens. During the floristic study, we detected conflictive and unresolved taxonomic and systematic questions regarding the genera Diploschistes and Ingvariella. In the second part of the thesis, we have tried to clarify these questions within a phylogenetic framework. In the revision of Diploschistes, the reconstruction of the phylogenetic relationships of the genera within its family (Graphidaceae) confirmed that the genus is monophyletic. We also reconstructed the phylogenetic relationships within Diploschistes using a combined dataset of morphological, chemical, and molecular data. The results show that the three groups traditionally distinguished within the genus (based on ascomatal morphology) are monophyletic. Therefore, it is proposed a new subgeneric treatment for Diploschistes, and it is confirmed the taxonomical value of fruiting body types. In The monotypic genus Ingvariella was segregated from Diploschistes based on fruiting body anatomy, and placed within the Thelotremataceae (= Graphidaceae), in the order Ostropales. Our morphological observations, however, suggest affinities to other families within the order. We inferred the phylogenetic relationships of a broad array of ostropalean fungi based on mtSSU and nuLSU. The results demonstrate that Ingvariella is monophyletic and belongs to the Stictidaceae, expanding the broad ecological diversity of this family
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First report of the pantropical species Diploschistes rampoddensis from Europe
'Mycotaxon Ltd.', 2026Co-Authors: Fernández Brime Samantha, Llimona Xavier, Hladun, Néstor L., Gaya Bellés I EsterAbstract:The lichen species Diploschistes rampoddensis, previously known only from a few localities in tropical and subtropical Asia and Oceania, is reported here for the first time in Europe. A detailed description, including macro- and microscopic characters, and comparisons with closely related taxa are also provided. Molecular analyses based on the nrITS were used to confirm this new record for the European lichen biota
Marcelo D. Serpe - One of the best experts on this subject based on the ideXlab platform.
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Bromus tectorum Litter Alters Photosynthetic Characteristics of Biological Soil Crusts from a Semiarid Shrubland
Soil Biology and Biochemistry, 2013Co-Authors: Marcelo D. Serpe, David J Eldridge, Eric Roberts, Roger RosentreterAbstract:Invasion by the exotic annual grass Bromus tectorum has increased the cover and connectivity of fine litter in the sagebrush steppes of western North America. This litter tends to cover biological soil crusts, which could affect their metabolism and growth. To investigate this possible phenomenon, biological soil crusts dominated by either the moss Bryum argenteum or the lichen Diploschistes muscorum were covered with B. tectorum litter (litter treatment) or left uncovered (control treatment) and exposed to natural field conditions. After periods of five and ten months, we removed the litter and compared the photosynthetic performance of biological soil crusts from the two treatments. Litter induced photosynthetic changes in our samples. In both B. argenteum and D. muscorum, biological soil crusts that had been covered with litter for ten months had lower rates of gross photosynthesis and lower chlorophyll content than control samples. Similarly in both biological soil crust types, litter reduced the rate of dark respiration. For D. muscorum, the reduction in dark respiration fully compensated for the decrease in gross photosynthesis, resulting in similar values of net photosynthesis in the two treatments. In contrast, for B. argenteum, net photosynthesis was four-times greater in the control than the litter treatment. Also under litter cover, D. muscorum showed three common adaptations to shade conditions: a decrease in the light compensation point, in the light intensity needed to achieve 95% of maximal net photosynthesis, and in the chlorophyll a/b ratio. None of these changes was apparent in B. argenteum. Overall, our results indicate that photosynthetic responses to the presence of litter varied among species of the crust biota and that the litter can reduce the photosynthetic capacity of biological soil crusts. These results help to explain field observations of decreases in biological soil crust cover and changes in biological soil crust composition with increases in litter cover, and suggest that the landscape-wide invasion by B. tectorum may have substantial effects on biological soil crust performance and therefore their capacity to function in semiarid shrublands.
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Seed water status and root tip characteristics of two annual grasses on lichen-dominated biological soil crusts
Plant and Soil, 2008Co-Authors: Marcelo D. Serpe, Shawna J. Zimmerman, Lynell Deines, Roger RosentreterAbstract:Biological soil crusts can affect seed germination and seedling establishment. We have investigated the effect of biological soil crusts on seed water status as a potential mechanism affecting seed germination. The seed water potential of two annual grasses, one exotic Bromus tectorum L. and another native Vulpia microstachys Nutt., were analyzed after placing the seeds on bare soil, on a crust that contains various lichens and mosses (mixed crust), or on a crust dominated by the crustose lichen Diploschistes muscorum (Scop.) R. Sant. ( Diploschistes crust). Seed water potential and germination were similar on the bare soil and the mixed crust, except for the initial germination of V. microstachys , which was higher on the mixed crust than on the bare soil. For the two grasses studied, seed water potential was significantly higher on the bare soil and mixed crust than on the Diploschistes crust. These differences in water potential correlated with differences in germination, which was much lower on the lichen crust. Experiments were conducted under two watering regimens. Increasing the frequency of watering amplified the differences in seed water potential and germination between the Diploschistes crust and the other two surfaces. For a particular watering regimen, the bare soil, mixed crust, and Diploschistes crust received the same amount of water, but they reached significantly different water potentials. Throughout the experiments, the water potential of the soil and mixed crust remained above −0.6 MPa, while there was a marked decline in the water potential of the Diploschistes surface to about −4 MPa. To ascertain that water was the major factor limiting germination on the Diploschistes crust, we conducted germination tests in an environment with 100% relative humidity. Under these conditions, germination on the Diploschistes crust was similar to that on the bare soil. However, the seeds that germinated on the Diploschistes crust did not penetrate this surface and approximately 60% of their root tips became necrotic. Our results indicate that the presence of D. muscorum can inhibit seedling establishment by two mechanisms: a reduction in seed water absorption and an increase in root tip mortality.
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Germination and seedling establishment of two annual grasses on lichen-dominated biological soil crusts
Plant and Soil, 2007Co-Authors: Lynell Deines, David J Eldridge, Roger Rosentreter, Marcelo D. SerpeAbstract:Biological soil crusts dominated by lichens are common components of shrub-steppe ecosystems in northwestern US. We conducted growth chamber experiments to investigate the effects of these crusts on seed germination and initial seedling establishment of two annual grasses; the highly invasive exotic Bromus tectorum L. and the native Vulpia microstachys Nutt. We recorded germination time courses on bare soil and two types of biological soil crusts; one composed predominantly of the lichen Diploschistes muscorum (Scop.) R. Sant. (lichen crust) and the other comprised of an assortment of lichens and mosses (mixed crust). Final germination on the lichen crust for both grass species was about a third of that on the bare soil surface. Mean germination time (MGT) was 3–4 days longer on the lichen crust compared with the bare soil. In contrast, there was no difference in germination percentage or MGT between the mixed crust and bare soil, and results were similar for both grass species. For both species, root penetration of germinating seeds on the lichen crust was lower than on the bare soil or mixed crust surfaces. The combined effects of the lichen crust on germination and root penetration resulted in an overall reduction in seedling establishment of 78% for V. microstachys and 85% for B. tectorum relative to the bare soil treatment. Our results clearly demonstrate that lichen-dominated biological soil crust can inhibit germination and root penetration, but the extent of these effects depends on the composition of the crust.
David J Eldridge - One of the best experts on this subject based on the ideXlab platform.
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Bromus tectorum Litter Alters Photosynthetic Characteristics of Biological Soil Crusts from a Semiarid Shrubland
Soil Biology and Biochemistry, 2013Co-Authors: Marcelo D. Serpe, David J Eldridge, Eric Roberts, Roger RosentreterAbstract:Invasion by the exotic annual grass Bromus tectorum has increased the cover and connectivity of fine litter in the sagebrush steppes of western North America. This litter tends to cover biological soil crusts, which could affect their metabolism and growth. To investigate this possible phenomenon, biological soil crusts dominated by either the moss Bryum argenteum or the lichen Diploschistes muscorum were covered with B. tectorum litter (litter treatment) or left uncovered (control treatment) and exposed to natural field conditions. After periods of five and ten months, we removed the litter and compared the photosynthetic performance of biological soil crusts from the two treatments. Litter induced photosynthetic changes in our samples. In both B. argenteum and D. muscorum, biological soil crusts that had been covered with litter for ten months had lower rates of gross photosynthesis and lower chlorophyll content than control samples. Similarly in both biological soil crust types, litter reduced the rate of dark respiration. For D. muscorum, the reduction in dark respiration fully compensated for the decrease in gross photosynthesis, resulting in similar values of net photosynthesis in the two treatments. In contrast, for B. argenteum, net photosynthesis was four-times greater in the control than the litter treatment. Also under litter cover, D. muscorum showed three common adaptations to shade conditions: a decrease in the light compensation point, in the light intensity needed to achieve 95% of maximal net photosynthesis, and in the chlorophyll a/b ratio. None of these changes was apparent in B. argenteum. Overall, our results indicate that photosynthetic responses to the presence of litter varied among species of the crust biota and that the litter can reduce the photosynthetic capacity of biological soil crusts. These results help to explain field observations of decreases in biological soil crust cover and changes in biological soil crust composition with increases in litter cover, and suggest that the landscape-wide invasion by B. tectorum may have substantial effects on biological soil crust performance and therefore their capacity to function in semiarid shrublands.
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Germination and seedling establishment of two annual grasses on lichen-dominated biological soil crusts
Plant and Soil, 2007Co-Authors: Lynell Deines, David J Eldridge, Roger Rosentreter, Marcelo D. SerpeAbstract:Biological soil crusts dominated by lichens are common components of shrub-steppe ecosystems in northwestern US. We conducted growth chamber experiments to investigate the effects of these crusts on seed germination and initial seedling establishment of two annual grasses; the highly invasive exotic Bromus tectorum L. and the native Vulpia microstachys Nutt. We recorded germination time courses on bare soil and two types of biological soil crusts; one composed predominantly of the lichen Diploschistes muscorum (Scop.) R. Sant. (lichen crust) and the other comprised of an assortment of lichens and mosses (mixed crust). Final germination on the lichen crust for both grass species was about a third of that on the bare soil surface. Mean germination time (MGT) was 3–4 days longer on the lichen crust compared with the bare soil. In contrast, there was no difference in germination percentage or MGT between the mixed crust and bare soil, and results were similar for both grass species. For both species, root penetration of germinating seeds on the lichen crust was lower than on the bare soil or mixed crust surfaces. The combined effects of the lichen crust on germination and root penetration resulted in an overall reduction in seedling establishment of 78% for V. microstachys and 85% for B. tectorum relative to the bare soil treatment. Our results clearly demonstrate that lichen-dominated biological soil crust can inhibit germination and root penetration, but the extent of these effects depends on the composition of the crust.
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distribution and floristics of terricolous lichens in soil crusts in arid and semi arid new south wales australia
Australian Journal of Botany, 1996Co-Authors: David J EldridgeAbstract:This paper examines the distribution of terricolous lichens at a regional scale across seven landscape types over 60 000 km2 in western New South Wales. Data are also presented on the distribution of lichens within a geomorphic sequence of runoff and runon zones on a red earth soil near Cobar. On a regional scale, 48 taxa from 23 genera were collected from 282 sites in semi-arid and arid eastern Australia, Of these, 74% were crustose or squamulose, and the remainder (26%) were foliose. Six genera (Acarospora, Endocarpon, Catapyrenium, Diploschistes, Peltula and Xanthoparmelia) accounted for 57% of species. Landscape type was a poor predictor of lichen floristics or crust cover. Instead, a core group of species comprising Collema coccophorum, Heppia despreauxii, Endocarpon rogersii, E. simplicatum var. bisporum, E. pallidum, Psora decipiens, Peltula patellata ssp. australiensis, Catapyrenium squamulosum and Synalissa symphorea, occurred in all landscape types. Plains with red earths had the greatest mean number of species per site (11.2) and the greatest mean crust cover (27.7%). Plains of calcareous earths yielded the greatest number of species (38). Across all sites, crust cover was a poor predictor of lichen species richness. However, on landscape types with non-calcareous soils, mean crust cover explained 88% of the variation in mean number of species. Whilst there was no difference in total number of species across a sequence of geomorphic zones, crust cover was significantly greater in the interception zones (79.0%) compared with either the run-on (6.6%) or run-off (24.0%) zones. These distributional data are compared with other published and unpublished studies from similar areas in Australia. The role of terricolous crusts as indicators of ecosystem health, and the influence of land management on crust cover and subsequent landscape stability are discussed.