Background and aims Understanding diaspore morphology and how much a species invests on dispersal... more Background and aims Understanding diaspore morphology and how much a species invests on dispersal appendages is key for improving our knowledge of dispersal in fragmented habitats. We investigate diaspore morphological traits in high-Andean Compositae, their main abiotic and biotic drivers and test whether they play a role in species distribution patterns across the naturally fragmented high-Andean grasslands. Methods We collected diaspore trait data for 125 Compositae species across 47 tropical high-Andean summits, focusing on achene length and pappus-to-achene length ratio, the latter as a proxy of dispersal investment. We analysed the role of abiotic (temperature, elevation and latitude) and biotic factors (phylogenetic signal and differences between tribes) on diaspore traits and whether they are related to distribution patterns across the Andes using phylogenomics, distribution modelling, and community ecology analyses. Key results Seventy-five percent of the studied species sh...
AimClimate change is transforming mountain summit plant communities worldwide, but we know little... more AimClimate 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.LocationHigh Andes.Time periodBetween 2011/2012 and 2017/2019.Major taxa studiedVascular plants.MethodsUsing 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 rel...
There is a great diversity of legume trees (Fabaceae) of ecologic and economic importance in the ... more There is a great diversity of legume trees (Fabaceae) of ecologic and economic importance in the city of Merida, Venezuela. Trees of this family are frequent and conspicuous in parks, gardens, squares and urban forest within the city. The present work includes descriptions and a general key to species, based on vegetative characters. As a result of the investigation, 25 genera and 42 species within 3 subfamilies are reported. Mimosoideae characterized by having bipinnate leaves, is the best represented subfamily (17 species); Caesalpinioideae is defined mainly having compound pinnately paripinnate leaves (except Bauhinia spp.) and Faboideae by having compound three-foliate and pinnately compound leaves.
Glaciers are receding at unprecedented rates in the alpine tropics, opening-up new areas for ecos... more Glaciers are receding at unprecedented rates in the alpine tropics, opening-up new areas for ecosystem assembly. However, little is known about the patterns/mechanisms of primary succession during the last stages of glacier retreat in tropical mountains. Our aim was to analyze soil development and vegetation assembly during primary succession, and the role of changing adaptive strategies and facilitative interactions on these processes at the forefront of the last Venezuelan glacier (Humboldt Peak, 4,940 m asl). We established a chronosequence of four sites where the glacier retreated between 1910 and 2009. We compared soil organic matter (SOM), nutrients and temperatures inside vs. outside biological soil crusts (BSCs) at each site, estimated the cover of lichen, bryophyte and vascular plant species present, and analyzed changes in their growth-form abundance and species/functional turnover. We also evaluated local spatial associations between lichens/bryophytes and the dominant ru...
Analyzing plant phenology and plant–animal interaction networks can provide sensitive mechanistic... more Analyzing plant phenology and plant–animal interaction networks can provide sensitive mechanistic indicators to understand the response of alpine plant communities to climate change. However, monitoring data to analyze these processes is scarce in alpine ecosystems, particularly in the highland tropics. The Andean páramos constitute the coldest biodiversity hotspot on Earth, and their species and ecosystems are among the most exposed and vulnerable to the effects of climate change. Here, we analyze for the first time baseline data for monitoring plant phenological dynamics and plant–pollinator networks along an elevation gradient between 4,200 and 4,600 m asl in three mountain summits of the Venezuelan Andes, which are part of the GLORIA monitoring network. We estimated the presence and density of plants with flowers in all the summits and in permanent plots, every month for 1 year. Additionally, we identified pollinators. We calculated a phenological overlap index between species. ...
Valeriana L. genus is represented in Venezuela by 16 species, 9 of these are endemic of Venezuela... more Valeriana L. genus is represented in Venezuela by 16 species, 9 of these are endemic of Venezuelan Andes growing in high mountains at 2 800 masl. In this investigation, four species were analyzed in order to determine the main secondary metabolites and antimicrobial activity of extracts obtained from aerial parts of Valeriana parviflora, V. rosaliana, V. triplinervis and V. phylicoides. Alkaloids, flavonoids, tannins, sterols, triterpenoids and saponins were qualitatively observed in all methanolic extracts tested. The color intensity or a precipitate formation was used as analytical response to these tests. Antimicrobial activity was evaluated against Gram positive, Gram negative bacterial strains and yeast, using disc diffusion method. N-hexane extracts of V. triplinervis and V. rosaliana showed the highest efficiency against Staphylococcus aureus, exhibiting inhibition zones of 16 mm and 15 mm; MIC (Minimal Inhibition Concentration) values were observed at 116 mg/mL and 150 mg/mL...
La familia Asteraceae es una de las más ricas en Venezuela. Pentacalia es el género con mayor can... more La familia Asteraceae es una de las más ricas en Venezuela. Pentacalia es el género con mayor cantidad de especies dentro de la misma y su principal área de distribución corresponde a los estados Mérida, Táchira y Trujillo. A pesar de su importancia, son pocos los estudios de anatomía xilemática para Pentacalia. El objetivo de este trabajo es la descripción anatómica de la madera de ocho especies de Pentacalia: P. cachacoensis, P. greenmaniana, P. imbricatifolia, P. mason-halei, P. pachypus, P. quirorana, P. reflexa y P. venezuelensis con el fin de encontrar caracteres útiles para su identificación. Las muestras fueron colectadas en los páramos de los estados Táchira y Mérida y en selva nublada de Mérida. La preparación del material se hizo utilizando los procedimientos de microtecnia xilemática y la descripción se realizó de acuerdo a lo estipulado por la asociación internacional de anatomistas de la madera. Las especies se pueden separar en dos grupos de acuerdo a la presencia o a...
This work deals with taxonomic and paleoecological aspects based on Quaternary fossil leaves from... more This work deals with taxonomic and paleoecological aspects based on Quaternary fossil leaves from Venezuela. It is the fi rst of its kind and therefore represents a novelty. The paleofl ora of the El Anís area, Mérida, presents itself as impressions/compressions of fossil angiosperm leaves, this association being very diverse, abundant, and well preserved, what allowed taxonomic treatment. Twentynine taxa were identifi ed belonging to the following families:
This study was conducted in the Facultad de Ciencias Forestales y Ambientales, Universidad de Los... more This study was conducted in the Facultad de Ciencias Forestales y Ambientales, Universidad de Los Andes (Merida-Venezuela), which has more than 60% of its area covered by green areas (natural and established), dominated by trees that serve different roles according to their place of establishment. In this regard, it were counted all tree and shrubs species, identifying each when possible in situ, in order to solve their botanical identity. 133 species were determined, on 46 families. The most abundant family was Fabaceae, with 14 genera and 21 species, followed by Euphorbiaceae and Myrtaceae, with nine species each. The found species were separated through vegetative characters, being the presence of latex, leaf type, size, shape, base, border and apex of the leaves, leaf arrangement, trichomes, venation, punctuations, nectaries, shape, length and width of the rachis the main ones. A key for the identification of the species was developed.
Valeriana L. genus is represented in Venezuela by 16 species, 9 of these are endemic of Venezuela... more Valeriana L. genus is represented in Venezuela by 16 species, 9 of these are endemic of Venezuelan Andes growing in high mountains at 2800 masl. In this investigation, four species were analyzed in order to determine the main secondary metabolites and antimicrobial activity of extracts obtained from aerial parts of Valeriana parviflora, V. rosaliana, V. triplinervis and V. phylicoides. Alkaloids, flavonoids, tannins, sterols, triterpenoids and saponins were qualitatively observed in all methanolic extracts tested. The color intensity or a precipitate formation was used as analytical response to these tests. Antimicrobial activity was evaluated against Gram positive, Gram negative bacterial strains and yeast, using disc diffusion method. N-hexane extracts of V. triplinervis and V. rosaliana showed the highest efficiency against Staphylococcus aureus, exhibiting inhibition zones of 16 mm and 15 mm; MIC (Minimal Inhibition Concentration) values were observed at 116 mg/mL and 150 mg/mL,...
Se realizo un estudio para la determinacion de especies arboreas a traves de caracteres vegetativ... more Se realizo un estudio para la determinacion de especies arboreas a traves de caracteres vegetativos en la Estacion Experimental Caparo, estado Barinas, Venezuela. Se establecieron dos transecciones y se hicieron recorridos en zonas aledanas a estas, a fin de colectar el mayor numero de individuos arboreos y elaborar una clave para la diferenciacion de las especies. Se encontraron 85 especies, pertenecientes a 35 familias y 72 generos, siendo Zanthoxylum setulosum y Allophylus amazonicus nuevos reportes para la flora de Venezuela. De las 35 familias reportadas, 33 estan ubicadas dentro del grupo de las Eudicotiledoneas, de estas, 26 pertenecen a las Rosidas (74%), siete a las Asteridas (20%) y dos a las familias basales (6%). La familia mas abundante fue Fabaceae con 19 especies, seguida de Malvaceae, Meliaceae y Moraceae, con siete especies cada una. Las especies estudiadas presentan caracteres vegetativos diagnostico conspicuos que permiten su determinacion, considerandose como pri...
Using data from 50 long-term permanent plots from across Venezuelan forests in northern South Ame... more Using data from 50 long-term permanent plots from across Venezuelan forests in northern South America, we explored large-scale patterns of stem turnover, aboveground biomass (AGB) and woody productivity (AGWP), and the relationships between them and with potential climatic drivers. We used principal component analysis coupled with generalized least squares models to analyze the relationship between climate, forest structure and stem dynamics. Two major axes associated with orthogonal temperature and moisture gradients effectively described more than 90% of the environmental variability in the dataset. Average turnover was 1.91 ± 0.10% year-1 with mortality and recruitment being almost identical, and close to average rates for other mature tropical forests. Turnover rates were significantly different among regions (p < 0.001), with the lowland forests in Western alluvial plains being the most dynamic, and Guiana Shield forests showing the lowest turnover rates. We found a weak pos...
Resumen En la ciudad de Mérida existe una gran variedad de leguminosas arbóreas, de importancia e... more Resumen En la ciudad de Mérida existe una gran variedad de leguminosas arbóreas, de importancia ecológica, medicinal, alimenticia y ornamental, siendo estas bastante comunes en parques, avenidas, plazas y áreas boscosas encontradas del casco urbano. En la presente investigación, se desarrolló una clave artificial para la identificación de las especies arbóreas de la familia Fabaceae presentes en la ciudad de Mérida, basadas en caracteres vegetativos. Se reportan 42 especies, distribuidas en 25 géneros y tres subfamilias, siendo la mejor representada la Mimosoideae con 17 especies; encontrando que existen caracteres vegetativos que determinan la diferenciación de cada una de estas subfamilias, en Faboideae se tienen como principales características las hojas compuestas trifolioladas y simplemente pinnadas; en Caesalpinioideae las hojas compuestas simplemente pinnadas, paripinnadas, exceptuando algunos géneros, con hojas compuestas bipinnadas y simples; mientras que en Mimosoideae casi todas los géneros presentan hojas compuestas bipinnadas.
Mecanografiado Informe de Pasantías (Tec. Sup. Forestal) -- Universidad de Los Andes, Facultad de... more Mecanografiado Informe de Pasantías (Tec. Sup. Forestal) -- Universidad de Los Andes, Facultad de Ciencias Forestales y Ambientales, Escuela Técnica Superior Forestal, Mérida, 2006 Incluye bibliografía
Mecanografiado Tesis (Magister Scientiae) -- Universidad de Los Andes, Centro de Estudios Foresta... more Mecanografiado Tesis (Magister Scientiae) -- Universidad de Los Andes, Centro de Estudios Forestales y Ambientales de Postgrado, Mérida, 2006 Incluye bibliografía e índice
Background and aims Understanding diaspore morphology and how much a species invests on dispersal... more Background and aims Understanding diaspore morphology and how much a species invests on dispersal appendages is key for improving our knowledge of dispersal in fragmented habitats. We investigate diaspore morphological traits in high-Andean Compositae, their main abiotic and biotic drivers and test whether they play a role in species distribution patterns across the naturally fragmented high-Andean grasslands. Methods We collected diaspore trait data for 125 Compositae species across 47 tropical high-Andean summits, focusing on achene length and pappus-to-achene length ratio, the latter as a proxy of dispersal investment. We analysed the role of abiotic (temperature, elevation and latitude) and biotic factors (phylogenetic signal and differences between tribes) on diaspore traits and whether they are related to distribution patterns across the Andes using phylogenomics, distribution modelling, and community ecology analyses. Key results Seventy-five percent of the studied species sh...
AimClimate change is transforming mountain summit plant communities worldwide, but we know little... more AimClimate 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.LocationHigh Andes.Time periodBetween 2011/2012 and 2017/2019.Major taxa studiedVascular plants.MethodsUsing 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 rel...
There is a great diversity of legume trees (Fabaceae) of ecologic and economic importance in the ... more There is a great diversity of legume trees (Fabaceae) of ecologic and economic importance in the city of Merida, Venezuela. Trees of this family are frequent and conspicuous in parks, gardens, squares and urban forest within the city. The present work includes descriptions and a general key to species, based on vegetative characters. As a result of the investigation, 25 genera and 42 species within 3 subfamilies are reported. Mimosoideae characterized by having bipinnate leaves, is the best represented subfamily (17 species); Caesalpinioideae is defined mainly having compound pinnately paripinnate leaves (except Bauhinia spp.) and Faboideae by having compound three-foliate and pinnately compound leaves.
Glaciers are receding at unprecedented rates in the alpine tropics, opening-up new areas for ecos... more Glaciers are receding at unprecedented rates in the alpine tropics, opening-up new areas for ecosystem assembly. However, little is known about the patterns/mechanisms of primary succession during the last stages of glacier retreat in tropical mountains. Our aim was to analyze soil development and vegetation assembly during primary succession, and the role of changing adaptive strategies and facilitative interactions on these processes at the forefront of the last Venezuelan glacier (Humboldt Peak, 4,940 m asl). We established a chronosequence of four sites where the glacier retreated between 1910 and 2009. We compared soil organic matter (SOM), nutrients and temperatures inside vs. outside biological soil crusts (BSCs) at each site, estimated the cover of lichen, bryophyte and vascular plant species present, and analyzed changes in their growth-form abundance and species/functional turnover. We also evaluated local spatial associations between lichens/bryophytes and the dominant ru...
Analyzing plant phenology and plant–animal interaction networks can provide sensitive mechanistic... more Analyzing plant phenology and plant–animal interaction networks can provide sensitive mechanistic indicators to understand the response of alpine plant communities to climate change. However, monitoring data to analyze these processes is scarce in alpine ecosystems, particularly in the highland tropics. The Andean páramos constitute the coldest biodiversity hotspot on Earth, and their species and ecosystems are among the most exposed and vulnerable to the effects of climate change. Here, we analyze for the first time baseline data for monitoring plant phenological dynamics and plant–pollinator networks along an elevation gradient between 4,200 and 4,600 m asl in three mountain summits of the Venezuelan Andes, which are part of the GLORIA monitoring network. We estimated the presence and density of plants with flowers in all the summits and in permanent plots, every month for 1 year. Additionally, we identified pollinators. We calculated a phenological overlap index between species. ...
Valeriana L. genus is represented in Venezuela by 16 species, 9 of these are endemic of Venezuela... more Valeriana L. genus is represented in Venezuela by 16 species, 9 of these are endemic of Venezuelan Andes growing in high mountains at 2 800 masl. In this investigation, four species were analyzed in order to determine the main secondary metabolites and antimicrobial activity of extracts obtained from aerial parts of Valeriana parviflora, V. rosaliana, V. triplinervis and V. phylicoides. Alkaloids, flavonoids, tannins, sterols, triterpenoids and saponins were qualitatively observed in all methanolic extracts tested. The color intensity or a precipitate formation was used as analytical response to these tests. Antimicrobial activity was evaluated against Gram positive, Gram negative bacterial strains and yeast, using disc diffusion method. N-hexane extracts of V. triplinervis and V. rosaliana showed the highest efficiency against Staphylococcus aureus, exhibiting inhibition zones of 16 mm and 15 mm; MIC (Minimal Inhibition Concentration) values were observed at 116 mg/mL and 150 mg/mL...
La familia Asteraceae es una de las más ricas en Venezuela. Pentacalia es el género con mayor can... more La familia Asteraceae es una de las más ricas en Venezuela. Pentacalia es el género con mayor cantidad de especies dentro de la misma y su principal área de distribución corresponde a los estados Mérida, Táchira y Trujillo. A pesar de su importancia, son pocos los estudios de anatomía xilemática para Pentacalia. El objetivo de este trabajo es la descripción anatómica de la madera de ocho especies de Pentacalia: P. cachacoensis, P. greenmaniana, P. imbricatifolia, P. mason-halei, P. pachypus, P. quirorana, P. reflexa y P. venezuelensis con el fin de encontrar caracteres útiles para su identificación. Las muestras fueron colectadas en los páramos de los estados Táchira y Mérida y en selva nublada de Mérida. La preparación del material se hizo utilizando los procedimientos de microtecnia xilemática y la descripción se realizó de acuerdo a lo estipulado por la asociación internacional de anatomistas de la madera. Las especies se pueden separar en dos grupos de acuerdo a la presencia o a...
This work deals with taxonomic and paleoecological aspects based on Quaternary fossil leaves from... more This work deals with taxonomic and paleoecological aspects based on Quaternary fossil leaves from Venezuela. It is the fi rst of its kind and therefore represents a novelty. The paleofl ora of the El Anís area, Mérida, presents itself as impressions/compressions of fossil angiosperm leaves, this association being very diverse, abundant, and well preserved, what allowed taxonomic treatment. Twentynine taxa were identifi ed belonging to the following families:
This study was conducted in the Facultad de Ciencias Forestales y Ambientales, Universidad de Los... more This study was conducted in the Facultad de Ciencias Forestales y Ambientales, Universidad de Los Andes (Merida-Venezuela), which has more than 60% of its area covered by green areas (natural and established), dominated by trees that serve different roles according to their place of establishment. In this regard, it were counted all tree and shrubs species, identifying each when possible in situ, in order to solve their botanical identity. 133 species were determined, on 46 families. The most abundant family was Fabaceae, with 14 genera and 21 species, followed by Euphorbiaceae and Myrtaceae, with nine species each. The found species were separated through vegetative characters, being the presence of latex, leaf type, size, shape, base, border and apex of the leaves, leaf arrangement, trichomes, venation, punctuations, nectaries, shape, length and width of the rachis the main ones. A key for the identification of the species was developed.
Valeriana L. genus is represented in Venezuela by 16 species, 9 of these are endemic of Venezuela... more Valeriana L. genus is represented in Venezuela by 16 species, 9 of these are endemic of Venezuelan Andes growing in high mountains at 2800 masl. In this investigation, four species were analyzed in order to determine the main secondary metabolites and antimicrobial activity of extracts obtained from aerial parts of Valeriana parviflora, V. rosaliana, V. triplinervis and V. phylicoides. Alkaloids, flavonoids, tannins, sterols, triterpenoids and saponins were qualitatively observed in all methanolic extracts tested. The color intensity or a precipitate formation was used as analytical response to these tests. Antimicrobial activity was evaluated against Gram positive, Gram negative bacterial strains and yeast, using disc diffusion method. N-hexane extracts of V. triplinervis and V. rosaliana showed the highest efficiency against Staphylococcus aureus, exhibiting inhibition zones of 16 mm and 15 mm; MIC (Minimal Inhibition Concentration) values were observed at 116 mg/mL and 150 mg/mL,...
Se realizo un estudio para la determinacion de especies arboreas a traves de caracteres vegetativ... more Se realizo un estudio para la determinacion de especies arboreas a traves de caracteres vegetativos en la Estacion Experimental Caparo, estado Barinas, Venezuela. Se establecieron dos transecciones y se hicieron recorridos en zonas aledanas a estas, a fin de colectar el mayor numero de individuos arboreos y elaborar una clave para la diferenciacion de las especies. Se encontraron 85 especies, pertenecientes a 35 familias y 72 generos, siendo Zanthoxylum setulosum y Allophylus amazonicus nuevos reportes para la flora de Venezuela. De las 35 familias reportadas, 33 estan ubicadas dentro del grupo de las Eudicotiledoneas, de estas, 26 pertenecen a las Rosidas (74%), siete a las Asteridas (20%) y dos a las familias basales (6%). La familia mas abundante fue Fabaceae con 19 especies, seguida de Malvaceae, Meliaceae y Moraceae, con siete especies cada una. Las especies estudiadas presentan caracteres vegetativos diagnostico conspicuos que permiten su determinacion, considerandose como pri...
Using data from 50 long-term permanent plots from across Venezuelan forests in northern South Ame... more Using data from 50 long-term permanent plots from across Venezuelan forests in northern South America, we explored large-scale patterns of stem turnover, aboveground biomass (AGB) and woody productivity (AGWP), and the relationships between them and with potential climatic drivers. We used principal component analysis coupled with generalized least squares models to analyze the relationship between climate, forest structure and stem dynamics. Two major axes associated with orthogonal temperature and moisture gradients effectively described more than 90% of the environmental variability in the dataset. Average turnover was 1.91 ± 0.10% year-1 with mortality and recruitment being almost identical, and close to average rates for other mature tropical forests. Turnover rates were significantly different among regions (p < 0.001), with the lowland forests in Western alluvial plains being the most dynamic, and Guiana Shield forests showing the lowest turnover rates. We found a weak pos...
Resumen En la ciudad de Mérida existe una gran variedad de leguminosas arbóreas, de importancia e... more Resumen En la ciudad de Mérida existe una gran variedad de leguminosas arbóreas, de importancia ecológica, medicinal, alimenticia y ornamental, siendo estas bastante comunes en parques, avenidas, plazas y áreas boscosas encontradas del casco urbano. En la presente investigación, se desarrolló una clave artificial para la identificación de las especies arbóreas de la familia Fabaceae presentes en la ciudad de Mérida, basadas en caracteres vegetativos. Se reportan 42 especies, distribuidas en 25 géneros y tres subfamilias, siendo la mejor representada la Mimosoideae con 17 especies; encontrando que existen caracteres vegetativos que determinan la diferenciación de cada una de estas subfamilias, en Faboideae se tienen como principales características las hojas compuestas trifolioladas y simplemente pinnadas; en Caesalpinioideae las hojas compuestas simplemente pinnadas, paripinnadas, exceptuando algunos géneros, con hojas compuestas bipinnadas y simples; mientras que en Mimosoideae casi todas los géneros presentan hojas compuestas bipinnadas.
Mecanografiado Informe de Pasantías (Tec. Sup. Forestal) -- Universidad de Los Andes, Facultad de... more Mecanografiado Informe de Pasantías (Tec. Sup. Forestal) -- Universidad de Los Andes, Facultad de Ciencias Forestales y Ambientales, Escuela Técnica Superior Forestal, Mérida, 2006 Incluye bibliografía
Mecanografiado Tesis (Magister Scientiae) -- Universidad de Los Andes, Centro de Estudios Foresta... more Mecanografiado Tesis (Magister Scientiae) -- Universidad de Los Andes, Centro de Estudios Forestales y Ambientales de Postgrado, Mérida, 2006 Incluye bibliografía e índice
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